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UNIVERSITY  OF  IOWA  STUDIES 

i- 

IN  NATURAL  HISTORY 


VOLUME  XI 
1925-1927 


University  of  Iowa 
1927 


irvci- 


CONTENTS 

No,  1  Fitzpatrick,  F.  L.  Ecology  and  economic  status  of 
citellus  tridecemlineatus 

No.  2  Horsfall,  J.  L.  Life  history  and  bionomics  of  aphis 
rumicis 

No.  3  De  Byke,  Willis.  The  development  of  the  renal  por- 
tal system  in  chrysemys  marginata  belli  (Gray) 

No.  4.  Mann,  W.  M.,  Viereck,  H.  L.,  Alexander,  C.  P., 
Wentworth,  C.  K.  Entomological  and  geological 
papers 

No.    5    Shimek,  Bohumil.    Papers  on  the  prairie 

No.    6    Byerly,  T.  C.    The  myology  of  sphenodon  punctattim 

No.  7  Mortensen,  Th.,  Deichmann,  Elisabeth,  Lindsey,  A. 
W.    Echinoderms  and  insects  from  the  Antilles 

No.  8  Thomas,  A.  O.,  Ladd,  H.  S.,  Lugn,  A.  L.  Papers  on 
geology 

No.  9  Jones,  D.  T.,  Potter,  G.  E.,  Marshall,  Ruth.  Fresh- 
water fauna  of  Iowa 

No.  10  Winters,  Grace  and  Lohman,  M.  L.  Papers  on  Iowa 
fungi 

No.  11  Wentworth,  Chester  K.  Methods  of  mechanical  an- 
alysis of  sediments 

No.  12  Larrabee,  Austin  P.  An  ecological  study  of  the  fishes 
of  the  Lake  Okoboji  region 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  1 


THE  ECOLOGY  AND  ECONOMIC  STATUS 
OF  CITELLUS  TRIDECEMLINEATUS 

by 
Fredrick  L.  Fitzpatrick 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


INTRODUCTION 

Citellus  tridecemlineatus  tridecemlineatus  was  first  described  by 
Dr.  S.  L.  Mitchill,  who  gave  it  the  common  names  c '  Thirteen-lined 
Ground  Squirrel"  and  " Federation  Ground  Squirrel."  The  lat- 
ter name  was  applied  because  of  a  fancied  resemblance  to  thirteen 
lines  of  stars  and  stripes.  (S.  F.  Baird,  1859,  p.  316).  The  sci- 
entific name  first  applied  by  Mitchill  in  1821  was  Sciurus  tridecem- 
lineatus. The  same  species  has  likewise  been  referred  to  as  Sper- 
mophilus  tridecemlineatus.  At  present  it  is  recognized  as  belong- 
ing to  the  genus  Citellus  and  the  species  is  divided  into  geographi- 
cal races. 

Various  common  names  for  this  animal  have  been  developed  lo- 
cally. Among  them  are  the  following:  "Striped  Prairie  Squir- 
rel," "Picket-pin,"  "Striped  Gopher/'  "Striped  Spermophile, " 
"Striped  Ground  Squirrel,"  "Thirteen-lined  Spermophile."  Only 
the  last  two  of  these  names  are  in  any  way  suitable,  for  the  rest 
tend  to  cause  confusion  with  other  species. 

This  rodent  was  selected  as  a  problem  for  study  because  very 
little  concrete  scientific  investigation  has  been  made  with  regard 
to  its  habits.  An  examination  of  the  bibliography  will  show  that 
while  a  number  of  authors  have  touched  upon  the  subject,  the  work 
has  been  universally  general  and  may  usually  be  summed  up  in  one 
or  two  pages.  In  fact  this  species  has  not  previously  been  the  sub- 
ject of  a  detailed  general  examination.  All  of  the  works  cited,  how- 
ever, have  some  bearing  on  the  problem  and  have  been  of  value  in 
its  development. 

Two  spermophiles  occur  commonly  in  Iowa:  Citellus  tridecem- 
lineatus tridecemlineatus  (Mitchill),  and  a  larger  species,  Citellus 
franklini  (Sabine).  They  vary  in  abundance  locally,  but  the  first 
named  form  usually  predominates  in  numbers  and  is  therefore  of 
most  interest  from  an  economic  standpoint. 

The  economic  status  of  Citellus  tridecemlineatus  tridecemlineatus 
has  been  a  subject  of  discussion  for  some  time.  Certain  counties 
have  even  gone  so  far  as  to  offer  a  bounty  for  this  species,  but  such 
plans  proved  impractical,  resulting  in  too  heavy  drains  on  county 
funds. 

Three  general  methods  were  employed  in  the  course  of  this  work. 

3 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

In  the  first  case  the  animals  were  observed  as  to  habits  and  general 
characteristics  both  in  the  field  and  in  captivity.  Then  specimens 
were  collected  at  different  times  of  the  year  and  studied  as  to  para- 
sites, stomach  contents,  and  embryonic  development.  Finally,  a 
large  number  of  burrows  were  excavated,  the  results  of  this  work 
being  chronicled  farther  on.  The  investigations  wTere  carried  on 
in  different  localities,  and  an  attempt  was  made  to  include  ex- 
tremes of  environment.  With  this  in  view  the  writer  has  made  a 
number  of  trips  to  different  parts  of  the  state. 

Some  difficulty  has  been  encountered  in  treating  this  subject 
coherently,  for  the  habits  are  in  every  case  dependent  upon  environ- 
ment. 

Before  closing  the  introduction  the  writer  wishes  to  express  his 
indebtedness  to  Professor  Henry  F.  Wickham  for  continuous  aid 
and  direction  in  the  pursuit  of  this  work.  And  also  to  Professors 
C.  C.  Nutting,  H.  R.  Dill,  and  Dayton  Stoner  for  encouragement 
and  helpful  suggestions. 

A  somewhat  different  acknowledgment  is  made  in  the  case  of  Mr. 
R.  A.  Brown  of  Des  Moines,  who  in  the  summer  of  1922  made  a 
collecting  tour  over  the  northern  part  of  Iowa  in  company  with  the 
writer,  and  who  proved  to  be  of  material  aid  in  the  securing  and 
preservation  of  stomach  contents. 


GENERAL  HABITS  AND  ENVIRONMENTAL 
CONDITIONS 

DISTRIBUTION 

Citellus  tridecemlineatus  tridecemlineatus  occurs  generally  in  the 
upper  Mississippi  valley  from  Ohio  west  to  the  plains,  and  from 
Missouri  and  Illinois  northward  into  Minnesota,  Wisconsin,  and 
Michigan.  To  the  westward  this  species  is  replaced  by  Citellus 
tridecemlineatus  pallidus,  which  form  is  very  similar  in  size  and 
habits  but  somewhat  lighter  in  coloration. 

Iowa  is  almost  in  the  center  of  the  range  covered  by  the  Thir- 
teen-lined  Spermophile.  Reports  from  all  parts  of  the  state  point 
to  a  practically  uniform  distribution,  the  animals  being  common 
residents  in  most  cases.  The  writer  has  selected  the  following  coun- 
ties as  examples  of  areas  in  which  this  species  is  particularly  abund 
ant:  Clay,  Dickinson,  Emmet,  Iowa,  Jones,  Louisa,  Pocahontas 
and  Polk.  It  must  be  remembered,  however,  that  abundance  in 
any  locality  is  variable,  being  dependent  on  an  ever  fluctuating  en- 
vironment. 

GENERAL  CHARACTERISTICS 

The  Thirteen-lined  Spermophile  has  a  number  of  well  defined 
habits.  One  of  these  is  the  characteristic  attitude  assumed  when 
listening  or  attracted  by  approaching  objects.  The  animals  sit  on 
their  hind  legs  in  an  erect  position  which  has  gained  for  them  the 
colloquial  term  ' '  Picket-Pins. ' '  Undeniably  curious  in  the  pres- 
ence of  man  these  spermophiles  will  assume  the  erect  attitude  and 
stare  at  the  intruder  for  an  indefinitely  long  period  of  time.  When 
crowded  too  closely  they  race  rapidly  to  their  holes  and  take  im- 
mediate refuge.  In  the  safety  of  their  retreats  they  will  often  stick 
their  heads  out  of  the  openings  for  brief  intervals  to  watch  the 
actions  of  their  enemy,  sometimes  uttering  their  familiar  call  mean- 
while, perhaps  as  a  warning  to  other  members  of  the  species.  They 
are  quick  and  seemingly  nervous  in  all  of  their  actions. 

The  Thirteen-lined  Spermophile  is  a  strictly  diurnal  species.  The 
animals  prefer  the  warmer  parts  of  the  day  for  their  activities  above 
ground,  particularly  when  the  sun  is  shining.  They  come  out  of 
their  retreats  for  successively  shorter  periods  each  day  as  the 
weather  becomes  colder. 

5 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  animals  have  a  tendency  toward  colonialism  and  live  in 
groups  as  a  rule.  Upland  or  lowland  valleys  with  few  or  no  trees 
are  habitually  inhabited  by  this  species.  Areas  where  the  grass  has 
been  closely  cut  down  by  stock  or  where  the  short  white  clover 
dominates  over  the  taller  blue-grass  are  preferred,  for,  as  will  ap- 
pear later,  the  animals  are  partially  dependent  upon  the  insects 
which  they  capture  for  food,  and  in  the  tall  vegetation  they  would 
be  at  a  great  disadvantage.  Heavy  timberlands  are  not  frequented 
although  in  open  wood-lots  there  may  be  occasional  burrows.  Sper- 
mophiles  are  apparently  independent  of  ponds  and  creeks  for  their 
water  supply  for  their  holes  are  often  found  on  the  crests  of  high 
broad  divides.  This  particular  subject,  however,  will  be  more  fully 
treated  in  the  succeeding  chapter. 

These  spermophiles  are  not  pugnacious  as  a  rule.  They  usually 
take  refuge  by  retreat  into  a  burrow  when  an  enemy  approaches. 
The  males  engage  in  minor  battles  among  themselves  during  the 
mating  season,  but  the  injuries  sustained  are  usually  negligible. 
(Stoner,  1918,  p.  131). 

SPRING  APPEARANCE  AND  MATING 
The  first  Thirteen-lined  Spermophiles  appear  above  ground  be- 
tween the  fifteenth  of  March  and  the  tenth  of  April,  depending  on 
the  season.  By  this  time  all  of  the  frost  has  been  thawed  out  and 
the  weather  is  reasonably  mild.  Their  advent  is  usually  preceded 
by  several  warm  sunny  days,  but  if  the  temperature  falls  the  sper- 
mophiles will  again  become  inactive  until  the  weather  moderates. 

Mating  does  not  take  place  immediately,  but  is  deferred  until 
about  the  second  or  third  week  in  April.  During  the  mating  season 
the  animals  are  unusually  active  and  spend  the  greater  part  of  the 
day  above  ground.  They  are  conspicuous  at  this  time  of  the  year, 
as  they  call  back  and  forth  continually.  The  males  engage  in  oc- 
casional fights  for  the  possession  of  mates. 

NESTS  AND  YOUNG 
During  the  first  week  in  May,  females  may  often  be  observed 
re-excavating  old  burrows.  If  killed  at  this  time  a  dissection  will 
generally  reveal  the  presence  of  well  developed  embryos.  Some  new 
burrows  are  constructed,  but  as  a  rule  tunnels  are  merely  hollowed 
out  and  new  nests  built.  Dead  grasses  of  the  preceding  year  are 
used  in  the  construction  of  these  nests.  Further  information  on 
this  subject  is  contained  in  Chapter  II.    Dissection  has  shown  that 


CITELLUS  TRIDECEMLINEATUS  7 

not  all  of  the  females  are  fertilized  and  in  one  instance  the  writer 
detected  a  diseased  condition  of  the  developing  embryos. 

There  is  great  variation  in  the  number  of  young  produced.  Adult 
females  of  the  preceding  year  show  a  general  tendency  toward  hav- 
ing fewer  offspring  than  the  older  females.  They  may  be  as  few 
as  four  or  as  many  as  ten  in  number.  Cory  (1912,  p.  141)  quotes 
Dr.  Hoy  to  the  effect  that  the  young  are  naked  at  birth,  blind  and 
remarkably  embryonic.  They  do  not  have  hair  until  they  are 
twenty  days  old  and  the  eyes  do  not  open  until  the  thirtieth  day. 
During  this  period  they  are  fed  and  otherwise  cared  for  by  the 
female.    Much  insect  food  is  carried  to  the  young. 

About  the  middle  of  July,  two-thirds  grown  young  appear  at 
the  surface  of  the  ground  and  begin  to  capture  or  otherwise  se- 
cure their  food.  Some  of  them  begin  to  dig  out  new  burrows,  some 
remain  in  the  parental  burrows,  and  still  others  wander  to  old  un- 
occupied burrows  or  retreats  in  the  near  vicinity.  The  relative 
quiet  of  the  reproductory  season  is  broken  now  and  the  members 
of  the  species  again  resume  their  former  habits. 

It  is  well  established  that  the  males  leave  the  females,  or  are 
driven  off  during  the  season  when  the  young  are  produced,  and 
assume  wandering  habits,  going  from  place  to  place  in  search  of 
food,  and  incidentally  constructing  many  new  retreats  in  the  pro- 
cess of  their  travels. 

LOCAL  MIGRATION  IN  SEARCH  OF  FOOD 
The  activities  of  mating  are  carried  on  for  the  most  part  in  the 
immediate  vicinity  of  the  place  where  the  animals  have  hibernated. 
After  mating,  however,  the  individuals  and  particularly  the  males, 
tend  to  spread  out  in  search  of  the  most  advantageous  feeding 
grounds.  Old  outlying  burrows  at  the  borders  of  fields  and  along 
roadsides  or  in  small  isolated  patches  of  grass  are  now  reoccupied. 
Early  in  the  summer  newly  planted  corn  may  be  attacked  to  some 
extent,  the  amount  of  actual  damage  depending  upon  the  number 
of  spermophiles  in  the  vicinity  and  the  presence  or  lack  of  other 
foods.  This  particular  topic  will  be  developed  under  "Food 
Habits. " 

The  writer  has  seen  these  spermophiles  leave  rather  large  areas 
entirely,  during  seasons  when  they  were  not  being  pastured  and 
the  grass  had  become  long.  For  as  previously  explained,  the  short 
grass  is  of  advantage  to  the  species,  and  if  it  becomes  tall  in  any 
locality  there  will  be  a  forced  migration  of  the  spermophiles.    This 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

is  a  general  rule  in  regard  to  local  distribution,  but  there  are  some 
few  cases  on  record  where  spermophiles  remained  far  out  in  hay- 
fields  during  the  early  part  of  the  summer  when  the  grass  averaged 
as  much  as  a  foot  in  height.  Here  they  were  no  doubt  practically 
dependent  on  vegetable  foods. 

Thirteen-lined  Spermophiles  will  immediately  encroach  upon 
newly-mown  fields  where  many  insects  are  easily  accessible  on  the 
fallen  hay  and  grain.  Here  they  will  remain  for  a  week  or  more, 
constructing  shallow  burrows  into  which  they  retreat  at  night  or 
when  threatened  by  any  of  their  various  natural  enemies. 

The  abundance  of  natural  enemies  tends  to  affect  distribution 
somewhat.  For  instance,  a  whole  pasture  may  be  depopulated  of 
spermophiles  by  the  attacks  of  a  single  Cooper's  Hawk. 

STORING  OF  FOOD 

Thirteen-lined  Spermophiles  seem  to  have  a  rather  moderately 
developed  instinct  to  store  food  materials  in  their  underground  re- 
treats. Such  a  practice  is  not  essential,  however,  and  is  not  re- 
sorted to  in  the  majority  of  cases.  The  writer  has  found  small 
caches  of  grain,  principally  corn,  on  several  occasions.  In  some 
cases  it  seems  that  the  food  was  stored  in  the  fall  and  remained 
untouched  until  the  following  spring  when  the  spermophiles  came 
out  of  hibernation. 

G.  E.  Johnson  (1917,  pp.  267-68)  reports  the  following  case  in 
regard  to  storage  of  food:  "The  burrow  occurred  in  a  pasture 
near  Canistota,  S.  Dak.,  fifteen  rods  from  an  oat  field.  The  first 
nest  was  about  two  feet  from  the  outside  opening,  the  entrance 
running  back  under  the  first  part  of  the  burrow.  This  nest  was 
filled  entirely  full  with  unshelled  oat  kernels  and  a  little  dry  grass, 
The  estimated  number  of  seeds  by  counting  one-sixteenth  of  them 
was  23,000  to  24,000.  This  nest  was  only  seven  inches  below  the 
surface  of  the  ground,  and  may  have  been  an  emergency  store- 
house. The  second  nest  was  about  sixteen  feet  from  the  first, 
measuring  along  the  burrow,  and  was  twelve  inches  below  the  sur- 
face of  the  ground.  It  was  seven  inches  in  diameter.  It  contained 
a  handful  of  dry  grass  and  about  4,000  oat  kernels  unshelled." 
Further  on  in  the  same  paper,  Johnson  records  the  storing  of  wheat 
kernels  in  a  similar  manner. 

It  is  the  opinion  of  the  writer  that  grain  is  sometimes  stored  when 
it  is  plentiful  and  easily  obtained.  Such  storages  are  used  in  case 
of  emergency  when  other  food  supplies  fail,  as  in  the  late  sum- 


CITBLLUS  TRIDECBMLINEATUS  9 

mer  and  fall  after  a  frost  when  the  insects  are  few  in  numbers.  The 
members  of  this  species  eat  insects  when  they  are  available,  but 
evidently  store  grain  during  the  harvest  season,  even  if  it  is  not 
the  principal  article  of  diet  at  the  time. 

PREPARATIONS  FOR  HIBERNATION 

The  first  indications  of  cold  weather  in  the  fall  result  in  a  marked 
diminishment  of  activities  on  the  part  of  Citellus  tridecemlineatus 
tridecemlineatus.  Some  warm  days  during  September  will  find 
these  spermophiles  above  ground.  There  is  some  excavation  going 
on,  as  old  burrows  are  deepened,  and  nests  are  lined  with  grass  in 
preparation  for  the  coming  winter.  No  doubt  the  great  majority 
of  the  species  simply  remain  in  the  deepest  burrows.  However, 
the  writer  has  noted  cases  where  this  species  took  over  much  larger 
abandoned  burrows  of  other  animals  in  the  fall.  In  one  case,  a 
spermophile  was  observed  carrying  nest  materials  into  the  former 
den  of  a  woodchuck,  at  Iowa  City,  September  14,  1922.  There  is 
no  doubt  that  in  some  cases  they  prefer  the  deeper  burrows  of  other 
animals  during  the  winter  season,  and  are  in  this  manner  enabled  to 
retreat  below  the  frost  line. 

All  existing  observations  seem  to  point  to  the  fact  that  each  in- 
dividual constructs  a  separate  hibernating  cell  or  nest.  Further, 
but  one  animal  hibernates  in  a  burrow  ordinarily.  In  one  case 
two  hibernating  nests  were  found  off  the  passages  of  a  common 
tunnel,  but  they  were  some  twenty  feet  apart. 

Just  before  hibernation  is  entered  upon,  all  the  openings  of  the 
burrow  are  plugged  with  dirt  for  a  distance  of  from  one  to  three 
feet.  If  there  is  a  succeeding  period  of  warm  weather,  the  plugs 
may  be  removed  temporarily,  but  they  usually  remain  until  the 
following  spring,  practically  obliterating  the  signs  of  the  burrow's 
presence. 

HIBERNATION 

As  has  been  inferred,  the  degree  of  activity  shown  by  Citellus 
iridecemlineatus  tridecemlineatus  is  directly  dependent  upon  tem- 
perature. Warm  sunny  days  find  the  spermophiles  above  ground 
and  extremely  active.  On  the  other  hand,  they  are  equally  inactive 
during  cool  rainy  weather,  even  in  mid-summer.  G.  E.  Johnson 
(1917,  p.  268)  reports  a  variation  of  4°  C.  in  the  temperature  of  an 
individual  during  a  single  day.  This  phenomenon  is  not  uncommon 
among  animals  which  ' '  hibernate ' '  in  the  true  sense  of  the  word. 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

After  closing  its  burrow  a  Thirteen-lined  Spermophile  curls  itself 
up  in  the  nest  previously  prepared  for  that  purpose  and  gradually 
passes  into  the  torpid  condition  known  as  hibernation  while  the 
surrounding  earth  is  becoming  cold.  If  the  spermophile  be  removed 
now  into  warmer  surroundings  it  will  gradually  revive,  but  will 
become  torpid  again  if  restored  to  the  colder  medium.  Experimen- 
tation has  shown  that  if  the  temperature  of  the  spermophile 's  body 
be  reduced  below  the  freezing  point  death  will  result  in  a  short 
time. 

The  life  processes  of  the  spermophile  must  be  sufficient  to  coun- 
teract the  cold  influence  of  the  walls  of  the  burrow,  for  the  animal 
hibernates  in  a  medium  which  is  often  well  below  the  freezing  point. 
On  the  other  hand,  the  vital  activities  must  be  reduced  sufficiently 
that  they  will  not  cause  too  heavy  a  drain  on  the  animal's  store  of 
fatty  tissue. 

Previous  investigations  as  to  the  actual  organic  conditions  of 
hibernation  have  been  successfully  conducted  by  Dr.  P.  R.  Hoy 
(1875,  pp.  148-50),  who  reports  the  following  interesting  facts: 
The  pulse  is  reduced  from  200  to  4  beats  per  minute.  Respiration 
is  reduced  from  50  to  practically  zero.  Temperature  falls  from 
105°  F.  to  58°  F.  Circulation  is  very  feeble  and  amputation  of  a 
limb  may  be  accomplished  with  very  little  loss  of  blood.  There  is  a 
prominent  congestion  of  blood  in  the  thoracic  region.  There  is  no 
muscular  response  to  stimuli,  not  even  if  a  nerve  be  severed. 


STRUCTURE  OF  BURROWS  AND  RETREATS 

FOREWORD 

The  examination  of  many  burrows  by  means  of  excavation  has 
made  clear  to  the  writer  that  their  construction  is  dependent  on  a 
large  number  of  varying  conditions.  The  different  kinds  of  bur- 
rows it  is  true,  fall  roughly  into  two  classes :  permanent  and  tem- 
porary, but  exceptions  to  even  the  most  general  types  are  met  with 
on  every  hand.  It  may  be  said  that  the  Thirteen-lined  Spermo- 
philes  show  a  certain  aptitude  to  take  advantage  of  favorable  con- 
ditions in  connection  with  the  construction  of  burrows.  This  fact 
alone  would  account  for  considerable  diversity  of  structure  since 
this  species  inhabits  a  variety  of  soils  under  many  changing  con- 
ditions of  agricultural  development. 

A  great  many  factors  must  be  taken  into  account  if  an  attempt 
is  made  to  correlate  the  structure  of  any  burrow  with  environ- 
mental circumstances.  The  kind  of  soil  may  be  considered  as  a 
determining  element.  Drainage,  elevation,  accessibility  of  food, 
character  of  vegetation  and  the  number  and  variety  of  natural 
enemies  serve  as  similar  influences.  In  many  cases  a  certain  type 
of  structure  may  be  traced  back  to  certain  combinations  of  these 
factors. 

In  Iowa,  Thirteen-lined  Spermophiles  are  found  both  in  the 
valleys  and  on  the  uplands.  They  migrate  back  and  forth  locally  in 
order  to  take  advantage  of  abundant  food  supplies.  As  an  example 
of  this  the  writer  has  often  noted  that  these  animals  are  particularly 
abundant  on  newly  raked  hay  fields.  The  reason  of  course  is 
obvious.  Many  of  the  insects  that  live  on  the  hay  in  the  early 
months  of  the  summer  are  now  left  on  the  short  stubble  where  they 
come  within  reach  of  the  spermophiles.  Accordingly  many  spermo- 
philes migrate  in  from  adjacent  pastures  to  take  advantage  of  this 
easily  obtained  food. 

The  Thirteen-lined  Spermophiles  never  venture  far  from  an 
underground  retreat  of  some  sort  and  this  habit  or  instinct  leads 
them  to  construct  new  burrows  or  renew  old  ones  whenever  they 
encroach  upon  new  territory.  Such  burrows  are  usually  of  a 
temporary  nature,  for  in  many  cases  the  vegetation  grows  up  later 
in  the  season  and  the  spermophiles  return  to  the  pasture  where 

11 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  grass  is  shorter.  This  general  example  is  cited  to  indicate  the 
multitude  of  conditions  which  may  directly  affect  the  habits  of 
this  species  and  indirectly  affect  the  construction  of  its  burrows. 

Local  migration  explains  many  things  in  connection  with  burrows 
that  would  otherwise  remain  a  mystery.  It  explains  the  fact  that 
the  number  of  burrows  is  relatively  large  in  proportion  to  the  num- 
ber of  individuals  living  in  the  vicinity.  As  a  rule  at  least  half  of 
the  burrows  in  a  given  region  will  be  unoccupied  although  at  any 
time  they  may  become  reinhabited.  In  this  connection  it  is  of  in- 
terest to  note  that  the  spermophiles  are  usually  found  singly  in 
separate  burrows  as  indicated  in  the  treatment  of  general  habits. 
This  habit  would  also  tend  toward  the  construction  of  a  compara- 
tively large  number  of  burrows  and  no  doubt  is  nearly  as  important 
a  factor  as  local  migration  itself. 

G.  E.  Johnson  (1917,  p.  264)  writes  with  reference  to  the  bur- 
rows of  Gitellus  tridecemlineatus  tndecemlineatus  as  follows :  "Ap- 
proximately fifteen  of  these  burrows  were  in  the  sandy  regions  of 
South  Chicago  (Nov.  11)  and  were  of  one  type,  about  two  feet  in 
length  and  eight  to  fourteen  inches  in  depth,  and  showing  no  evi- 
dence of  recent  occupancy.  .  .  .  The  remaining  burrows  were 
in  sod  (humus)  with  clay  subsoil.  These  ranged  from  four  to 
twenty  feet  in  length  and  from  four  to  forty-six  inches  in  depth. 
Of  the  seventy-eight  burrows  measured,  thirty-seven  per  cent  were 
two  feet  or  less  in  length  and  nine  inches  or  less  in  depth;  while 
sixty-seven  per  cent  were  four  feet  or  less  in  length  and  thirteen 
inches  or  less  in  depth ;  and  only  fourteen  per  cent  were  longer  than 
six  feet  or  deeper  than  seventeen  inches. ' ' 

The  first  burrows,  referred  to  as  being  in  the  sandy  region  about 
Chicago,  are  no  doubt  examples  of  temporary  structures  which  had 
been  in  use  during  the  summer  as  a  result  of  local  abundance  of 
food.  As  winter  approached  (remembering  that  there  is  little  ac- 
tivity among  the  members  of  this  species  after  the  first  of  Novem- 
ber) the  spermophiles  would  naturally  withdraw  to  older,  deeper 
burrows,  leaving  the  former  in  the  unoccupied  condition  that  they 
were  found  by  Mr.  Johnson.  The  last  part  of  the  quotation  is  in- 
cluded to  substantiate  a  point  brought  out  in  the  preceding  pages ; 
that  there  is  a  great  variety  of  burrow  structure  and  that  there 
are  many  small  temporary  burrows  in  proportion  to  the  number 
of  long  permanent  tunnels.  It  will  be  observed  that  Mr.  Johnson 
credits  only  fourteen  per  cent  of  the  burrows  as  being  longer  than 


CITELLUS  TRIDECEMLINBATUS  13 

six  feet.  He  divides  the  remaining  burrows  into  two  classes,  one 
group  about  two  feet  long,  the  other  group  about  four  feet  in 
length.  In  the  writer's  opinion  the  latter  two  classes  may  to  all  in- 
tents and  purposes  be  regarded  as  representing  the  same  thing; 
simply  refuges  or  places  for  temporary  shelter.  Mr.  Johnson's 
observations  likewise  indicate  at  least  a  fundamental  similarity 
between  the  conditions  of  construction  existing  in  the  region  he 
refers  to  (Illinois)  and  the  conditions  to  be  found  in  Iowa. 

Before  closing  the  introduction  it  seems  fitting  to  make  some  men- 
tion of  the  manner  in  which  these  animals  dig.  G.  E.  Johnson 
(ibid.,  p.  266)  reports  the  keeping  of  a  number  of  these  animals  in 
captivity  and  the  observance  of  their  digging  habits.  He  is  quoted 
in  part  as  follows :  ' i  In  digging,  the  ground  squirrel  makes  a  few, 
quick,  alternating  strokes  with  its  fore  legs  throwing  the  sand  about 
its  hind  legs.  This  is  followed  by  a  straightening  of  the  body  and 
quick  alternating  strokes  by  the  hind  legs  which  throw  the  soil 
back  with  great  force,  at  the  same  time  scattering  it." 

The  writer  has  observed  much  the  same  process  in  the  field, 
especially  during  the  breeding  season  when  the  old  males  were 
roaming  about  constructing  new  retreats.  In  some  cases  the  dirt 
seems  to  be  scattered  away  from  the  hole,  at  least  in  part,  but  in 
many  instances  no  apparent  attempt  is  made  to  conceal  the  open- 
ing. The  writer  is  of  the  opinion  that  the  spermophiles  do  not  try 
to  hide  their  excavations,  and  that  the  dirt  at  the  mouth  of  a  hole 
is  only  scattered  when  it  accumulates  in  such  quantity  that  it  in- 
terferes with  the  activities  of  the  animal.  Holes  are  eventually 
rendered  inconspicuous  by  the  washing  away  of  loose  dirt  and  re- 
growth  of  the  sod.  The  fact  that  the  animals  habitually  dig  their 
burrows  in  exposed  places,  when  in  many  cases  locations  under 
bushes  or  at  the  edges  of  hayfields  and  weed  patches  present  them- 
selves, argues  against  any  very  strong  instinctive  tendency  to  con- 
ceal the  burrows. 

As  previously  intimated,  the  concrete  discussion  of  the  subject 
will  be  divided  into  separate  considerations  of  the  temporary  and 
the  permanent  burrows.  As  the  separation  into  these  two  groups 
is  based  principally  on  length,  no  sharp  line  can  be  drawn  between 
the  two  classes  and  the  division  is  more  or  less  artificial.  Its  use 
is  justified,  however,  for  it  has  enabled  the  writer  to  bring  out  the 
correlation  of  the  animals'  life  habits  and  the  types  of  burrows  that 
are  utilized.    Specific  cases  and  diagrams  are  included  in  the  fol- 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

lowing  pages,  the  examples  being  selected  primarily  to  show  di- 
versity of  structure.  Habits  which  are  closely  dependent  on  bur- 
row structure  are  necessarily  included  although  they  come  more 
properly  within  the  field  of  general  habits.  In  order  to  treat  the 
subject  as  coherently  as  possible  the  insects  found  in  the  different 
burrows  are  simply  listed  in  this  chapter  as  they  form  the  subject 
matter  for  a  later  discussion. 

TEMPORARY  BURROWS 

The  structures  which  may  be  regarded  as  temporary  burrows  or 
retreats  are  usually  short  and  of  simple  construction.  For  all  prac- 
tical purposes  the  length  may  be  used  to  indicate  the  nature  of  any 
particular  burrow. 

The  great  majority  of  the  burrows  fall  into  this  class.  It  is 
likely  that  even  the  permanent  nesting  burrows  are  at  first  shallow 
retreats,  a  few  being  dug  out  and  developed  because  of  natural  ad- 
vantages, while  the  most  of  the  retreats  are  of  only  passing  value 
dependent  upon  circumstances,  and  eventually  fall  into  disuse. 

In  any  pasture  inhabited  by  the  Thirteen-lined  Spermophile  a 
careful  examination  and  some  excavation  will  reveal  the  fact  that 
there  are  many  short  burrows  within  a  few  yards  of  what  are  known 
to  be  old  established  dens.  Further  observation  will  show  that 
most  of  these  short  tunnels  or  pockets  (for  they  are  often  merely 
passage-ways  under  stumps,  which  require  little  effort  on  the  ani- 
mal's part  in  construction)  are  not  developed  during  the  summer 
but  are  used  casually,  nevertheless,  by  the  inhabitants  of  the  region. 
This  condition  varies  in  degree,  and  is  dependent  largely  on  the 
extent  to  which  the  animals  are  persecuted  by  natural  enemies. 
For  these  short  pockets  are  used  principally  as  refuges  into  which 
the  animals  retire  to  eat  the  various  food  materials  which  they 
obtain  above  ground.  Usually  the  walls  of  the  tunnel,  especially 
near  the  entrance,  will  show  the  presence  of  small  bits  of  clover, 
grass  or  insect  remains.  The  spermophiles  increase  their  feeding 
territory  and  yet  insure  themselves  against  surprise  attacks  by  con- 
structing a  number  of  these  small  refuges. 

If  stumps  are  present  in  the  infested  pasture,  many  holes  will 
be  found  about  their  roots.  Tunnels  from  the  holes  usually  lead 
directly  beneath  the  stumps,  where  natural  cavities  formed  by 
decay  are  taken  advantage  of.  There  may  be  one  or  more  than  one 
opening,  often  there  are  two,  and  more  rarely  three.    The  openings 


CITELLUS  TRIDBCEMLINEATUS  15 

may  be  at  the  very  edge  of  the  stump  or  occasionally  a  foot  or  more 
away.    Plate  I,  fig.  1,  shows  an  example  of  this  type. 

A  tunnel  passes  around  the  stump  to  join  two  holes  on  opposite 
sides.  Often  there  is  a  natural  central  cavity  beneath  the  stump, 
due  to  decay,  and  accessible  from  the  tunnel  at  various  points. 

Plate  I,  fig.  2,  shows  a  temporary  retreat  that  was  located  in  a 
pasture  region  among  several  permanent  burrows.  This  little  bur- 
row measured  some  three  and  a  half  feet  in  total  length  and  was 
not  more  than  ten  inches  deep  at  any  point.  At  the  time  of  in- 
vestigation both  openings  were  plugged.  This  is  often  found  to 
be  the  case  when  the  burrow  is  not  in  use  and  no  explanation  can 
be  given  in  most  instances. 

Occasionally  these  retreats  under  stumps  are  developed  in  an  in 
teresting  and  peculiar  manner.  As  the  stump  decays  it  gradually 
falls  apart  or  becomes  overturned  or  otherwise  broken  away  from 
the  roots.  This  leaves  the  former  retreat  exposed  or  partially  so 
at  least.  In  hard  soils,  clays  particularly,  the  roots  will  become 
partially  pulverized  while  the  soil  is  so  dry  and  hard  that  it  will 
not  immediately  fill  the  cavities  caused  by  the  decay.  The  sper- 
mophiles  take  advantage  of  this  fact,  and  the  writer  has  excavated 
many  passages  which  occupied  the  spaces  formerly  filled  by  roots. 
In  fact,  the  old  bark  was  often  found  lining  the  walls.  For  the 
bark  is  thin  and  resistant  and  does  not  decay  until  the  internal 
portion  of  the  root  has  long  been  gone. 

Plate  I,  fig.  3,  is  a  diagram  of  a  short  burrow  with  two  openings. 
It  is  included  because  the  distal  part  of  the  burrow  occupied  the 
former  position  of  a  branching  root  which  was  mainly  decayed 
away. 

The  writer  was  at  a  loss  for  some  time  in  trying  to  account  for 
some  long  burrows  which  took  a  fairly  straight  course  and  yet 
ended  blindly  after  gradually  becoming  smaller  in  diameter  up 
to  the  point  that  they  would  not  permit  the  passage  of  a  spermo- 
phile.  Johnson  (1917,  p.  268)  reports  the  discovery  of  some  long 
tunnels  that  ended  blindly  and  suggests  that  they  might  function 
as  drains.  No  mention  was  made  of  any  tapering  in  size  so  these 
burrows  may  not  have  been  similar  to  those  mentioned  above.  It 
is  the  opinion  of  the  writer,  however,  that  most  of  these  cases  can 
be  explained  by  the  fact  that  the  passages  occupy  the  positions  of 
former  roots. 

It  is  difficult  to  say  to  just  what  extent  the  spermophiles  utilize 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

old  root  passages.  Probably  they  remove  bits  of  decaying  wood 
and  otherwise  hollow  out  the  tunnels  so  formed  to  suit  their  con- 
veniences. Burrows  of  this  nature  are,  however,  temporary  re- 
treats only.  They  are  longer  than  the  ordinary  retreats  because 
their  construction  is  not  dependent  on  the  spermophile's  efforts 
alone.  Some  of  these  longer  retreats  are  no  doubt  remodeled  event- 
ually to  become  permanent  nesting  burrows  as  they  are  typically 
found  in  the  hard  soil  of  pastures  where  this  species  prefers  to  con- 
struct its  more  permanent  homes.  But  in  such  case  the  constant 
use  of  the  passages  obliterates  all  traces  of  former  relations  with 
regard  to  the  roots.  Hence  this  feature  is  usually  noticeable  only 
in  the  temporary  burrows. 

An  example  of  a  temporary  burrow  which  occupied  the  former 
position  of  a  root  is  shown  in  the  drawing  on  Plate  II,  fig.  1.  This 
burrow  had  been  in  active  use  the  entire  summer  until  a  few  days 
before  the  time  the  excavation  was  made.  (September  8).  A  short 
period  of  cold  weather  had  put  a  stop  to  activities  on  the  part  of 
the  spermophiles  and  the  burrow  was  abandoned.  It  was  located 
in  an  upland  pasture,  bare  stump  land  for  the  most  part. 

The  burrow  had  been  plugged  with  loose  dirt  for  a  distance  of 
a  foot  or  more  from  the  mouth.  In  one  pocket  about  three  feet 
from  the  external  opening,  a  toad  was  found  which  had  evidently 
selected  this  location  in  which  to  hibernate.  The  burrow  followed 
the  course  of  a  decayed  root.  In  fact,  there  were  three  holes  near 
the  one  diagrammed,  with  burrows  radiating  from  the  location  of  a 
former  stump.  The  walls  of  the  passageway  were  lined  with  old 
bark  and  in  some  cases  it  was  possible  to  remove  whole  cylinders 
of  the  latter  without  breaking  it.  As  would  be  expected  the  tun- 
nel became  progressively  smaller  toward  the  distal  end,  and  it  was 
obvious  that  this  portion  was  not  used  to  any  extent. 

A  somewhat  different  situation  is  shown  in  Plate  II,  fig.  2.  This 
burrow  was  observed  to  be  in  use  the  year  preceding  its  excavation, 
but  had  evidently  not  been  used  as  a  nesting  burrow.  At  the  time 
of  excavation  (August  14,  1922)  there  was  much  dirt  in  the  pas- 
sage from  B  to  C  and  it  was  evident  that  the  burrow  was  being 
lengthened.  As  in  the  previous  case  this  burrow  followed  the 
course  of  a  decayed  root.  There  were  two  openings  (A  and  B). 
The  burrow  was  located  in  an  upland  pasture. 

Cory  (1912,  p.  141)  quotes  Kennicott  as  saying  that  in  Illinois 
the  males  leave  the  females  during  the  season  when  the  young  are 


CITELLUS  TRIDECEMLINEATUS  17 

produced  and  wander  about  digging  temporary  burrows  or  living 
in  some  abandoned  ones  for  a  few  days  at  a  time.  He  says  that 
some  of  these  burrows  are  as  much  as  twenty  feet  in  length  and 
contain  nests  placed  in  side  chambers. 

The  writer  is  inclined  to  believe  that  these  longer  burrows  were 
not  constructed  for  strictly  temporary  use  but  has  noticed  their 
presence  if  a  summer  retreat  was  well  situated  with  reference  to 
the  food  supply  and  was  used  quite  regularly  accordingly.  How- 
ever, this  wandering  habits  of  the  males  no  doubt  accounts  for  many 
of  the  short,  abandoned  and  sometimes  isolated  burrows. 

G.  E.  Johnson  (1917,  p.  264)  mentions  the  discovery  of  short 
burrows  in  Illinois  and  says  that  they  are  evidently  refuges  used 
in  journeys  between  a  food  source  and  permanent  burrows  some 
distance  away.  In  the  same  article  Johnson  mentions  that  short 
burrows  were  found  associated  with  deeper  burrows  in  pastures. 

But  by  no  means  all  of  the  temporary  shelters  are  of  the  same 
nature  and  location  as  the  foregoing.  The  spermophiles  move  about 
locally  with  reference  to  the  food  supply.  Their  fondness  for 
grasshoppers  leads  them  into  newly  cut  fields.  Here  they  will  re- 
main until  the  conditions  which  facilitate  the  securing  of  food  are 
no  longer  operating. 

So  we  find  many  short  retreats  scattered  over  the  hay  and  grain 
fields  in  the  late  summer.  They  are  constructed  in  the  rather  loose 
soil  and  are  very  temporary,  being  obliterated  during  the  winter 
or  by  plowing  in  the  spring.  Some  of  these  burrows  command  a 
more  favorable  location,  being  preserved  by  the  proximity  of  a 
fence  or  some  other  obstacle.  In  such  cases  they  may  even  become 
permanent  eventually,  especially  if  they  are  near  a  pasture.  For 
this  sort  of  location  is  admirably  suited  to  the  animals'  needs  as 
they  can  feed  on  the  short  pasture  during  the  summer  and  retreat 
into  the  holes  in  the  grass  of  a  neighboring  field  when  threatened 
by  natural  enemies.  Similarly,  under  such  conditions  many  of 
their  movements  are  concealed  from  other  animals  that  prey  upon 
them. 

PERMANENT  BURROWS 

From  the  exterior  there  is  no  apparent  difference  between  a  per- 
manent burrow  and  one  of  a  temporary  nature.  The  only  indi- 
cation of  a  permanent  structure  may  be  the  fact  that  several  holes 
are  in  close  proximity,  for  there  are  almost  invariably  two  openings 
to  the  old  established  burrows.     Then,  too,  they  are  usually  situ- 


18  IOWA  STUDIES  IN  NATUEAL  HISTORY 

ated  in  hard  soil,  pastures  being  favored,  for  it  is  necessary  to 
have  the  permanent  home  in  ground  that  is  not  plowed  constantly 
and  is  firm  enough  to  prevent  collapse  of  the  passages  from  rains 
or  freezing  and  thawing. 

Plate  III  represents  an  upland  pasture  burrow  which  was  at 
least  three  years  old  and  perhaps  much  older.  It  was  located  on 
a  hillside  in  hard,  dry,  well  drained  soil.  The  passages  themselves 
indicated  considerable  age,  being  rather  wider  than  the  average 
and  showing  signs  of  wear. 

Two  interesting  facts  were  made  clear  in  the  course  of  excava- 
tion. The  pocket  A,  which  incidentally  marks  the  deep- 
est point  of  the  burrow,  was  used  only  for  the  dumping  of  wastes. 
This  was  found  to  be  duplicated  by  similar  conditions  in  previous 
excavations  and  in  this  instance  the  proof  was  conclusive.  The 
pocket  was  over  half  filled  with  coprolites,  many  of  them  being  of 
recent  deposition. 

The  passageway  B  is  of  interest  because  it  was  hollowed  out 
within  a  decayed  root  which  came  from  the  stump  E,  as  indicated 
by  the  dotted  lines. 

No  nests  were  present  although  this  was  an  old  burrow.  This  is 
explainable  in  that  old  nests  are  walled  in  during  the  summer  and 
especially  after  the  young  are  capable  of  caring  for  themselves. 
This  burrow  was  excavated  August  9,  1922,  at  which  date  the 
young  would  have  left  the  parental  home.  Without  doubt  the  en- 
largement at  D  marks  the  former  site  of  a  nest,  used  either  for 
hibernation  in  winter  or  for  the  raising  of  young.  It  is  notable 
that  this  is  practically  the  deepest  point  in  the  burrow.  The  en- 
largement at  C  is  no  doubt  due  to  constant  use  of  the  passage  at 
this  point.  It  is  habitual  with  the  spermophiles  to  carry  food 
within  the  mouth  of  the  burrow,  where  it  can  be  eaten  with  more 
safety. 

Plate  IV,  fig.  1,  represents  a  burrow  from  the  border  of  a  dry 
creek  bed  in  a  pasture  area.  It  was  entered  from  the  north  where 
two  openings  gave  access  to  the  exterior.  It  will  be  noted  that  a 
short  passage  about  four  feet  from  the  openings  leads  to  a  nest. 
This  nest  was  of  recent  construction  and  in  a  good  state  of  preser- 
vation. The  date,  July  27,  1923,  indicates  that  this  was  about  the 
end  of  the  season  that  the  young  are  in  the  nests. 

The  passage  continued  on  nearly  two  feet  from  the  nest,  and  was 
plugged  with  dirt  after  turning  slightly.     Coprolites  were  found 


CITELLUS  TRIDECBMLINBATUS  19 

scattered  on  the  floor  of  the  pocket  thus  formed,  which  bears  out 
the  testimony  of  Plate  III. 

The  plug  having  been  removed,  the  tunnel  was  found  to  lead 
to  another  rather  new  nest,  which  was  placed  directly  beneath  a 
stump,  between  the  spreading  and  decaying  roots.  A  passage  ex- 
tended to  the  surface  here,  while  a  deeper  tunnel  continued  through 
beneath  the  nest.  This  latter  tunnel  took  a  sharp  bend  to  the  left 
and  assumed  a  more  or  less  straight  course  for  over  six  feet.  This 
was  followed  by  an  elbow  bend  where  an  old  nest  was  walled  in. 
The  materials  of  the  nest  were  the  usual  grasses,  but  they  were 
old  and  were  mixed  with  bits  of  oak  leaves,  indicating  that  the 
nest  had  been  there  since  the  preceding  fall  and  may  have  served  as 
the  retreat  of  a  spermophile  during  the  winter  months.  Some  shells 
that  represented  corn  grains  were  found  mixed  with  the  nest  ma- 
terials, and  they  too  showed  signs  of  considerable  age.  It  is  notable 
again  that  this  nest  was  at  the  deepest  point  of  the  burrow,  being 
some  28  inches  below  the  surface. 

Plate  IV,  fig  2,  gives  an  example  of  a  rather  short  shallow  bur- 
row that  was  evidently  used  as  a  place  to  raise  young.  There  was 
one  inhabitant  at  the  time  of  excavation,  a  young  male  about 
two-thirds  grown. 

The  nest  was  situated  in  an  oval  chamber  about  six  inches  in 
depth.  This  pocket  had  been  partially  filled  with  dead  and  fresh 
grasses  mixed  with  loose  dirt.  This  rude  nest  was  covered  with 
insect  remains  and  bits  of  wilted  clover  which  no  doubt  represented 
food  that  had  been  brought  to  the  young.  Several  grubs  were 
found  in  or  about  the  nest.  This  burrow  was  excavated  June  26, 
1922.  It  was  located  in  an  upland  field  and  had  obviously  been  con- 
structed the  same  year.  It  was  of  course  much  shorter  than  the 
average  pasture  burrow. 


G.  E.  Johnson  (1917,  p.  264)  brings  out  the  relative  scarcity 
of  the  long  permanent  burrows  when  he  states  that  only  six  of 
nearly  eighty  burrows  which  he  examined  were  found  to  be 
branched.  He  likewise  states  that  the  animals  were  observed  to 
construct  nests  while  in  captivity,  in  which  they  slept  when  not 
active.  The  writer  observed  the  same  habit  when  experimenting 
with  captive  spermophiles.  It  must  be  remembered,  however,  that 
an  animal  does  not  necessarily  react  in  a  normal  way  when  taken 
out  of  its  natural  environment. 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

In  regard  to  nest  structure  the  following  is  quoted  from  John- 
son (ibid.,  p.  267)  : 

"It  is  in  the  nest  also  that  food  is  stored  as  was  proved  by  the 
presence  of  grain  in  the  nests  of  the  three  ground  squirrels  re- 
ferred to,  and  in  practically  every  nest  examined  in  the  field.  Oats, 
wheat,  corn,  and  weed  seeds  have  been  frequently  found  between 
the  excavated  space  in  the  ground  and  the  grassy  nest  that  filled 
it.  In  the  recently  occupied  burrows  this  food  varied  from  con- 
siderable in  the  late  summer  to  a  small  amount  in  the  late  autumn. 
The  nests  were  usually  found  in  the  longer  and  deeper  burrows. 
Of  the  seventy-eight  burrows  recorded  twenty-two  had  nests  con- 
nected with  them.     Two  of  these  had  two  nests/ ' 

"Some  of  the  nests  were  found  to  one  side  of  the  burrows, 
others  at  the  ends  of  the  burrows  and  still  others  in  the  direct  course 
or  at  an  angle  of  the  burrow.  .  .  .  This  nest  was  filled  entirely 
full  with  unshelled  oat  kernels  and  a  little  dry  grass.  The  esti- 
mated number  of  seeds  by  counting  one-sixteenth  of  them  was  23, 
000  to  24,000. " 

The  writer's  own  experience  with  nests  was  somewhat  similar 
to  the  above.  Possibly  there  seemed  to  be  less  of  a  tendency  to 
store  grain,  but  this  could  be  accounted  for  by  varying  local  condi- 
tions as  to  the  availability  of  food.  The  habit  of  storing  grain  is 
certainly  not  universal  among  the  spermophiles. 

Cory  (1912,  p.  141)  quotes  Kennicott  as  saying  that  the  nests 
were  sometimes  as  large  as  a  half  bushel,  the  interior  being  lined 
with  soft  material.  The  writer  found  no  case  of  a  nest  this  large. 
The  largest  were  about  ten  inches  in  diameter  and  these  were 
demonstrated  to  be  nests  used  in  rearing  the  young. 

One  phase  of  burrow  structure  remains  to  be  touched  upon ;  the 
type  of  retreat  used  during  hibernation.  Some  work  has  been  done 
on  this  subject  previously,  the  information  being  collected  by  ac- 
cidental discoveries  of  individuals  undergoing  hibernation.  The 
testimony  is  to  the  general  effect  that  the  animals  hibernate  in  nests 
in  the  deeper  burrows.    This  is  too  well  established  to  be  questioned. 

Interesting  exceptions  occur  however.  The  writer  observed  two 
cases  of  spermophiles  taking  over  abandoned  burrows  of  larger 
animals,  which  were  of  course  deeper  and  went  down  below  the 
frost  line.  But  the  great  majority  of  the  spermophiles  hibernate 
in  their  own  burrows. 


CITELLUS  TRIDECEMLINEATUS  21 

GENERAL  CONCLUSIONS  AND  ECONOMIC  BEARING 

From  the  standpoint  of  agriculture  the  burrows  themselves  are 
harmless  enough.  They  may  even  be  of  some  slight  benefit  in  al- 
lowing the  rainfall  to  soak  into  the  ground  more  completely.  On 
golf  links,  parade  grounds,  parks  and  similar  areas  the  holes  may 
often  become  a  serious  nuisance. 

If  control  measures  are  attempted  in  any  locality,  the  signifi- 
cance of  burrow  structure  has  a  direct  bearing  on  the  subject.  For 
if  poisoned  grain,  for  instance,  is  to  be  laid  in  the  burrows,  the 
time  to  do  it  is  obviously  in  the  early  spring  when  the  animals 
first  appear  and  may  be  found  almost  exclusively  in  pastures  or 
near  the  deeper  burrows.  A  little  observation  will  show  at  once 
where  the  ground  squirrels  are  to  be  found  at  this  time.  Later 
on  in  the  summer  the  problem  of  extermination  is  made  much  more 
complicated  by  the  scattering  out  of  the  individual  spermophiles 
and  the  occupancy  of  the  many  small  retreats.  But,  as  will  ap- 
pear later,  the  necessity  for  control  is  the  exception  rather  than 
the  rule.  And  almost  all  of  the  serious  damage  donS  by  this  species 
is  confined  to  the  planting  season. 

As  to  the  stage  of  grain  and  the  relations  of  food  to  burrows,  the 
subject  is  developed  in  a  succeeding  chapter  on  food  habits.  It 
is,  however,  of  economic  importance,  and  a  study  of  burrow  struc- 
ture is  necessary  in  order  to  fully  understand  it. 


FOOD  HABITS  AND  ECONOMIC  STATUS 

FOREWORD 

While  engaged  in  a  field  survey  and  study  of  Citellus  tridecem- 
lineatus  tridecemlineatus  some  one  hundred  and  twelve  stomachs 
were  preserved. 

The  writer  found  that  the  best  method  in  preservation  was  to 
empty  the  stomach  contents  into  a  small  wide-mouthed  bottle  of 
70%  alcohol.  This  was  preferable  to  placing  the  entire  stomach 
in  preservative  because  when  this  latter  method  was  employed  the 
alcohol  did  not  penetrate  the  rather  thick  stomach  wall  soon  enough 
to  prevent  the  beginning  of  decay. 

The  spermophiles  chew  their  food  well  before  swallowing  it  and 
the  materials  in  the  stomach  are  always  well  broken  up  even  before 
the  digestive  juices  have  acted  upon  them  to  any  considerable  ex- 
tent. Hence  the  stomach  contents  are  quick  to  decay  upon  the 
animal's  death. 

The  fact  that  these  stomach  contents  are  so  well  pulverized  has 
an  obvious  disadvantage  from  the  standpoint  of  the  investigator, 
for  in  almost  all  cases  it  is  impossible  or  at  least  impractical  to 
attempt  accurate  identification  of  the  insect  remains.  Occasionally, 
legs  of  grasshoppers  are  swallowed  without  being  completely  mutil- 
ated. Some  larval  segments  may  also  remain  more  or  less  intact. 
Hulls  of  the  common  grains  are  sometimes  swallowed  entire,  as  are 
many  weed  seeds. 

But  fortunately,  on  the  other  hand,  Citellus  tridecemlineatus 
tridecemlineatus  seems  to  prefer  many  of  the  common  and  well 
known  grains  as  well  as  some  of  the  common  and  conspicuous  in- 
sects. So  the  work  of  identification  was  not  entirely  hopeless.  It 
is  the  opinion  of  the  writer  that  the  results  obtained  are  entirely 
dependable  and  quite  characteristic  of  the  species. 

W.  L.  Burnett  (1914,  p.  11)  mentions  the  same  difficulties  in 
identifying  the  stomach  contents  of  Citellus  tridecemlineatus  palli- 
dus.  Furthermore  he  is  of  the  opinion  that  it  is  somewhat  easier 
to  identify  the  vegetable  materials  than  to  identify  the  insect  re- 
mains. 

22 


CITELLUS  TRIDECEMLINEATUS  23 

DATA  GAINED  FROM  FORMER  INVESTIGATIONS 
OF  FOOD 

C.  P.  Gillette  (1889)  examined  some  twenty-two  stomachs  of 
Citellus  tridecemlineatus  tridecemlineatus,  the  animals  being  killed 
between  April  19  and  August  2.  He  found  that  insects  made  up 
a  large  proportion  of  the  food,  and  further,  that  the  insects  eaten 
were  almost  exclusively  injurious.  He  stated  it  as  his  opinion  that 
this  animal  was  of  decided  benefit  to  gardens,  lawns,  meadows, 
and  pastures.  Similarly,  he  believed  that  this  spermophile  would 
be  advantageous  to  cornfields  if  it  could  be  prevented  from  digging 
up  the  newly  planted  grain,  for  it  would  destroy  large  numbers 
of  cutworms  before  planting  time. 

J.  M.  Aldrich  (1892)  in  summing  up  some  examinations  of  the 
food  of  Citellus  tridecemlineatus  tridecemlineatus  found  that  rel- 
atively large  numbers  of  cut- worms,  grasshoppers  and  crickets 
were  eaten.  Some  neutral  beetles  were  also  found  in  the  food  ma- 
terials. Aldrich  seemed  to  think  that  this  species  was  approxi- 
mately neutral  in  its  economic  importance. 

W.  L.  Burnett  (1914,  p.  10)  gives  some  very  interesting  data 
with  reference  to  Citellus  tridecemlineatus  pallidus.  He  states 
that  a  specimen  kept  in  captivity  would  leave  all  other  foods  un- 
touched when  grasshoppers  were  available.  The  legs  and  wings  of 
the  grasshoppers  were  not  eaten.  This  specimen  would  catch,  kill, 
and  eat  mice  as  well  as  grasshoppers,  when  these  animals  were 
placed  in  its  cage. 

W.  L.  Burnett  (ibid.,  p.  11)  gives  the  following  list  of  food  ma- 
terials eaten  by  Citellus  tridecemlineatus  pallidus  where  in  cap- 
tivity: sunflower  seed,  grass  seed,  dandelion  seed,  pumpkin  seed, 
sugar  beet  seed,  watermelon  seed,  muskmelon  seed,  young  chickens, 
squash  seed,  speltz,  beans,  grasshoppers,  crickets,  beetles,  alfalfa 
roots  and  leaves,  corn,  cane,  oats,  wheat,  kaffir  corn,  rye,  milo 
maize,  peas,  barley,  peanuts  and  field  mice. 

Some  forty-six  stomachs  of  Citellus  tridecemlineatus  pallidus 
were  examined  by  Burnett  (ibid.,  p.  15).  All  of  these  specimens 
were  taken  in  northern  Colorado  during  the  summers  of  1912,  1913 
and  1914.  He  found  the  stomachs  to  contain  a  rather  high  per- 
centage of  animal  matter.  Remains  of  grasshoppers,  beetles  and 
field  mice  predominated.  Corn,  alfalfa,  spiders,  caterpillars  and 
in  one  case  a  bird  feather,  were  found  in  the  various  stomachs. 


24  IOWA  STUDIES  IN  NATUEAL  HISTORY 

DAMAGE 

The  principal  charge  against  this  species  is  that  it  destroys  young 
crops.  Corn  crops  are  sometimes  damaged  to  the  extent  that  re- 
planting becomes  necessary. 

The  attacks  usually  occur  along  the  margins  of  cornfields  which 
are  bordered  by  meadows.  The  spermophiles  dig  down  at  the  base 
of  each  newly-sprouted  corn  stalk  and  in  this  manner  obtain  the 
planted  grain.     The  young  corn  dies  as  a  result. 

Such  depredations  are  quite  common  throughout  the  state  of 
Iowa.  Fortunately,  however,  the  damage  is  so  slight  that  it  usually 
passes  unnoticed.  It  is  seldom  that  the  corn  is  molested  beyond 
the  third  row  from  the  edge  of  the  field.  But  occasionally,  if  the 
spermophiles  are  present  in  Urge  numbers  the  actual  loss  to  the 
farmer  may  be  considerable. 

A  few  years  ago  when  this  species  was  somewhat  more  numerous 
in  individuals,  serious  losses  of  young  corn  were  not  uncommon. 
Stoner  (1918,  p.  32)  quotes  an  early  report  of  Vernon  Bailey  to  the 
effect  that  large  fields  of  corn  were  sometimes  destroyed  and  had 
to  be  planted  over  several  times.  Even  fields  of  small  grain  were 
at  times  seriously  damaged  by  spermophile  invasions  in  the  late 
eighties  of  the  past  century. 

But  according  to  all  available  reports  the  numbers  of  spermo- 
philes have  been  very  materially  reduced  in  the  last  decade.  It  is 
perhaps  safe  to  say  that  there  has  been  a  fifty  per  cent  reduction  in 
the  preceding  five  years.  Bounties  have  been  offered  for  this 
species,  and  literature  has  been  circulated  about  the  country  advis- 
ing the  people  as  to  the  different  methods  used  in  poisoning  rodents. 

With  this  loss  in  numbers  has  come  corresponding  reduction  in 
the  amount  of  damage  done.  Occasionally  one  hears  accounts  of 
attacks  upon  corn.  The  writer  has  recently  investigated  some  of 
these  claims  and  has  found  that  they  are  very  generally  grossly 
exaggerated. 

As  far  as  attacks  on  oats,  wheat,  barley,  rye,  and  similar  crops 
are  concerned,  the  damage  is  of  little  consequence.  These  grains 
may  be  attacked  just  after  sprouting.  But  the  destruction  is  never 
great  enough  to  necessitate  replanting.  Occasionally  the  ripe  grain 
is  eaten  or  stored  in  the  fall,  as  mentioned  in  preceding  discussions. 
However,  grasshoppers  are  easily  obtainable  at  this  season  of  the 
year,  and  Citellus  tridecemlineatus  tridecemlineatus  prefers  these 
insects  to  any  other  form  of  food. 


CITELLUS  TRIDECEMLINEATUS  25 

It  has  been  claimed  that  garden  crops  are  sometimes  injured  by 
this  species.  The  writer,  however,  has  been  unable  to  discover  any 
real  proof  of  this.  No  doubt  peas,  beans,  and  similar  vegetables  are 
sometimes  taken,  but  certainly  not  in  any  considerable  quantities 
Spermophiles  kept  in  captivity  would  only  eat  peas,  beans,  and  the 
seeds  of  other  garden  plants  when  no  other  foods  were  available: 

There  is  little  or  no  damage  to  pasture  land  because  of  the  pres- 
ence of  burrows.  No  obstructions,  such  as  piles  of  loose  dirt,  are 
thrown  up  by  this  species.  Similarly,  there  is  practically  no  in- 
jury to  the  grass  because  it  almost  always  grows  up  to  the  very 
edges  of  the  holes. 

There  is  no  doubt,  however,  that  the  burrows  are  somewhat  of  a 
nuisance  to  golf  links,  parade  grounds,  and  similar  areas  where 
a  smooth  unbroken  surface  is  desirable. 

BENEFITS  DERIVED 

At  the  beginning  of  this  consideration  we  are  confronted  by  the 
fact  that  we  cannot  hope  to  determine  the  identity  of  many  insect 
remains  found  in  the  stomachs  of  this  species.  For  not  only  does 
this  animal  chew  up  its  food  very  thoroughly,  but  it  bites  off  and 
discards  the  heads,  wings,  and  legs  of  the  insects  in  most  cases, 
and  these  rejected  parts  are  the  ones  that  lend  themselves  particu- 
larly well  to  identification.  But  the  task  is  by  no  means  hopeless, 
and  it  is  possible  to  make  some  fairly  accurate  estimates. 

Of  the  larvae  eaten  in  the  spring  it  is  safe  to  say  that  a  great 
many  are  detrimental  to  agricultural  pursuits.  For  they  are  of 
necessity  species  that  live  upon  the  cultivated  crops  and  grasses. 
It  has  previously  been  determined  that  cut-worms  constitute  a 
regular  article  of  diet  at  this  season. 

It  is  quite  true  that  Citellus  tridecemlineatus  tridecemlineatus 
exercises  little  or  no  choice  in  the  selection  of  insect  food  in  the 
spring,  probably  because  the  insects  are  none  too  numerous  at  this 
time.  But  in  the  fall  when  insect  life  is  abundant  and  diversified 
a  very  decided  choice  is  exercised. 

Perhaps  the  strongest  argument  in  favor  of  the  Thirteen-lined 
Spermophile  is  the  fact  that  it  consumes  large  quantities  of  grass- 
hoppers in  the  latter  part  of  the  season.  It  is  observable,  both  in 
the  field  and  in  the  cases  of  animals  kept  in  captivity,  that  the 
members  of  this  species  seem  to  prefer  grasshoppers  to  any  other 
food.  Grasshopper  remains  may  be  identified  among  the  stomach 
contents  because  in  this  case  the  enlarged  proximal  portions  of  the 


26  IOWA  STUDIES  IN  NATURAL  HISTOEY 

hind  legs  are  often  swallowed  entire.  The  heads,  wings,  and  re- 
maining leg  parts  are  discarded.  The  appended  chart  (Plate  V), 
shows  what  a  large  proportion  of  the  food  matter  is  made  up  of 
grasshoppers,  particularly  in  the  late  summer  and  early  fall.  Some 
weed  seeds  are  eaten  by  the  Thirteen-lined  Spermophile  at  every 
season  of  the  year.  Here,  however,  there  is  apparently  very  little 
choice  in  the  selection  of  food,  and  whatever  is  most  accessible  is 
utilized.  Seeds  of  rag  weed,  hemp,  fox-tail,  and  pig  weed  are  com- 
monly eaten.  But  on  the  other  hand  clover  seed  forms  a  staple 
article  of  diet,  whenever  available.  And  ordinarily  the  eating  of 
clover  seed  would  be  considered  as  disadvantageous  to  agricultural 
interests.  So  perhaps  the  good  done  in  the  destruction  of  weed 
seeds  is  counterbalanced  by  the  harm  done  in  consumption  of 
clover  seed. 

ECONOMIC  CONCLUSIONS  WITH  REGARD  TO 
THE  FOOD  HABITS 

C.  P.  Gillette  (1889)  believed  that  Citellus  tridecemlineatus 
tridecemlineatus  was  advantageous  to  agricultural  pursuits.  He 
examined  twenty-two  stomachs  and  based  his  conclusions  on  the  re- 
sults of  this  investigation. 

J.  M.  Aldrich  (1892)  investigated  Spermophilus  tridecemlinea- 
tus, and  seemed  inclined  to  consider  this  form  about  neutral  in 
economic  status.  This  work  was  done  in  the  Dakotas,  so  the  species 
referred  to  was  undoubtedly  what  is  known  as  Citellus  tridecem- 
lineatus pallidus. 

W.  L.  Burnett  (1914)  collected  forty-six  stomachs  of  the  western 
subspecies,  Citellus  tridecemlineatus  pallidus.  As  in  the  case  of 
the  present  investigation  a  large  proportion  of  the  food  was  found 
to  consist  of  insect  remains.  Burnett  probably  considered  this 
species  to  be  neutral  in  its  economic  importance.  It  is  interesting 
to  note  the  answers  he  received  to  letters  of  inquiry  that  were  sent 
out  to  some  of  the  farmers  of  northern  Colorado.  In  every  case  the 
farmers  were  quick  to  notice  any  depredations,  but  they  failed  to 
recognize  that  any  good  might  result  from  the  presence  of  this 
form.  A  parallel  could  be  pointed  out  in  the  former  public  atti- 
tude toward  many  of  our  useful  hawks  and  owls. 

Vernon  Bailey  (1893,  p.  42)  examined  stomach  contents  of  this 
species  and  its  geographical  races.  He  came  to  the  conclusion  that 
it  probably  did  more  harm  than  good.  Harm  by  virtue  of  the 
damage  to  young  crops,  and  good  because  of  the  numbers  and  kinds 


CITELLUS  TRIDECEMLINEATUS  27 

of  insects  eaten.  The  writer  is  inclined  to  think  this  was  a  very- 
fair  estimate.  But  as  before  intimated,  since  the  numbers  of 
spermophiles  have  been  greatly  reduced,  the  damage  to  young 
crops  is  negligible. 

It  is  even  likely  that  this  species  will  not  disturb  the  corn,  if 
represented  by  only  a  moderate  number  of  individuals.  For  when 
the  spermophiles  are  not  especially  numerous,  they  can  obtain 
enough  food  in  the  way  of  insect  larvae  without  leaving  their  nat- 
ural haunts  and  invading  the  cultivated  fields. 

A  glance  at  the  appended  chart  will  show  the  high  percentage  of 
insects  eaten  by  Citellus  tridecemlineatus  tridecemlineatus.  Further 
observations  will  show  that  the  majority  of  these  insects,  taking  an 
average  for  the  season,  are  grasshoppers.  It  is  safe  to  say  that 
grasshoppers  cause  a  five  per  cent  annual  loss  to  hay  crops  alone. 

Without  doubt,  this  species  acts  as  an  important  natural  check 
upon  the  increase  of  grasshoppers. 

Man's  attempts  to  disturb  the  balance  in  nature  have  quite  com- 
monly resulted  in  disaster  from  an  agricultural  standpoint,  par- 
ticularly when  he  has  destroyed  some  species  which  acted  as  a  nat- 
ural check  upon  a  noxious  form.  We  find  an  example  of  this  in 
the  destruction  of  the  Prairie  Chicken  and  the  succeeding  increase 
in  the  numbers  of  grasshoppers. 

It  is  the  opinion  of  the  writer  that  unless  some  very  serious  charge 
is  brought  against  a  species,  it  is  the  part  of  safety  to  leave  the 
balance  of  nature  undisturbed,  especially  in  cases  like  the  one  under 
consideration  where  the  animal  preys  upon  an  undesirable  form. 

As  intimated  in  the  preceding  pages,  these  spermophiles  are 
not  numerous  enough  in  most  localities  to  destroy  any  great  amount 
of  young  corn.  Should  they  become  too  populous  in  a  given  area 
it  is  a  simple  matter  to  reduce  their  numbers  practically  overnight. 
Some  effective  means  of  eliminating  these  animals  will  be  found 
in  the  following  chapter.  In  conclusion,  we  may  even  admit  that 
with  the  exception  of  grasshoppers,  no  discrimination  is  exercised 
in  the  choice  of  insect  foods.  Perhaps  equal  numbers  of  beneficial 
and  harmful  insects  are  destroyed.  But  in  any  event,  if  the  dam- 
age to  young  corn  is  not  serious,  it  is  most  emphatically  desirable 
to  retain  this  species  as  a  check  upon  grasshoppers.  For  even  a 
one  per  cent  increase  in  the  numbers  of  grasshoppers  would  mean 
a  very  large  total  loss  to  cultivated  crops  each  year. 

So  as  long  as  this  species  exists  in  moderate  numbers  it  may  be 


28  IOWA  STUDIES  IN  NATUBAL  HISTORY 

regarded  as  a  desirable  element  in  the  fauna  of  a  given  region. 
Certainly  active  measures  to  secure  its  elimination  should  not  be 
necessary. 

ANALYSIS  OF  STOMACH  CONTENTS 
In  the  following  pages  analyses  of  the  materials  found  in  eighty- 
two  stomachs  will  be  found.  As  previously  stated,  one  hundred  and 
twelve  stomachs  were  collected  in  1922  and  1923.  All  of  these 
were  examined,  but  a  number  of  them  proved  to  be  empty.  The 
latter  have  not  been  included  in  this  appendix  because  they  have  no 
particular  significance.  They  merely  represented  individuals  killed 
in  the  early  part  of  the  day,  probably  before  any  food  had  been 
eaten. 

Stomach  No.  1 — female;  Iowa  City,  Iowa;  May  14,  1922. 

85%  insect  larvae. 

10%  blue  grass  and  white  clover  tips. 
5%  weed  seeds. 
Stomach  No.  2 — female;  Iowa  City,  Iowa;  May  14,  1922. 

60%  insect  larvae. 

30%  blue  grass  and  white  clover. 
7%  weed  seeds. 

3%   unidentified  vegetable  materials. 
Stomach  No.  3 — male;   Iowa  City,  Iowa;   May  14,   1922. 

80%  insect  larvae,  at  least  one-half  of  them  cutworms. 

20%  vegetable  matter.     Chiefly  grass  and  white  clover. 
Stomach  No.  4 — male;  Iowa  City,  Iowa;  May  16,  1922. 

20%  insect  larvae. 

40%  corn. 

25%  grass  and  white  clover. 
5%  various  weed  seeds. 

10%    unidentified    vegetable    materials. 
Stomach  No.  5 — male;   Williamsburg,  Iowa;   May  20,  1922. 

40%  insect  remains.     Evidently  all  larvae. 

40%  corn. 

20%   grass,   clover,   and  unidentified   vegetable  matter. 
Stomach  No.  6 — female;  Victor,  Iowa;  May  21,  1922. 

45%  insect  remains. 

20%  corn. 

20%   clover  and  grass. 
5%  weed  seeds. 

10%  unidentified  vegetable  materials. 
Stomach  No.  7 — female;  Victor,  Iowa;  May  21,  1922. 

Stomach  nearly  empty.     Some  signs  of  insect  remains. 
Stomach  No.  8 — male;  Victor,  Iowa;  May  21,  1922. 

30%  insect  remains. 

60%  white  clover. 


CITELLUS  TRIDECEMLINBATUS  29 

10%  unidentified  vegetable  materials. 
Stomach  No.  9 — female;  Iowa  City,  Iowa;  May  28,  1922. 

20%  white  clover. 

10%  various  weed  seeds. 

60%  corn. 

10%   unidentified  materials. 
Stomach  No.  10 — male;  Iowa  City,  Iowa;  May  28,  1922. 

40%  white  clover  seed. 

20%  various  weed  seeds. 

20%   grass  and  clover. 

20%  unidentified  matter. 
Stomach  No.  11 — female;  Iowa  City,  Iowa;   May  28,  1922. 

40%  insect  remains. 

30%  wheat. 

15%  blue  grass  and  white  clover. 

15%  unidentified. 
Stomach  No.  12 — female;  Iowa  City,  Iowa;  May  28,  1922. 

This  stomach  was  practically  empty.    A  few  corn  hulls  were  found. 
Stomach  No.  13 — male;  Iowa  City,  Iowa;  May  29,  1922. 

20%  insect  matter. 

30%  wheat. 

40%  grass  and  white  clover. 

10%  unidentified. 
Stomach  No.  14 — female;  Iowa  City,  Iowa;  June  2,  1922. 

This  specimen  filled  with  the  remains  of  a  field  mouse. 
Stomach  No.  15 — female;  Iowa  City,  Iowa;  June  2,  1922. 

30%  insect  remains. 

10%  corn. 

20%  white  clover  seed. 

40%  grass  and  clover. 
Stomach  No.  16 — male;  Iowa  City,  Iowa;  June  3,  1922. 

30%  insect  remains. 

20%  corn. 

50%  blue  grass  and  clover. 
Stomach  No.  17 — male;  North  Liberty,  Iowa;  June  4,  1922. 

35%  insect  larvae. 

25%  corn. 

40%  blue  grass  and  clover. 
Stomach  No.   18 — female;    North  Liberty,   Iowa;    June  4,   1922. 

40%  insect  matter. 

55%  grass. 
5%  weed  seed. 
Stomach  No.  19 — female;  Eagle  Grove,  Iowa;  June  10,  1922. 

40%  insect  larvae. 

40%  grasses. 

10%  weed  seed. 

10%  unidentified. 


30  IOWA  STUDIES  IN  NATUKAL  HISTORY 

Stomach  No.  20 — male;  Iowa  City,  Iowa;  June  29,  1922. 

60%  remains  of  a  field  mouse. 

30%  insect  larvae. 

10%  grass,  clover,  and  clover  seed. 
Stomach  No.  21 — female;  Iowa  City,  Iowa;  June  29,  1922. 

60%  white  clover  seed. 

30%  blue  grass  and  white  clover. 

10%  unidentified. 
Stomach  No.  22 — female;  Iowa  City,  Iowa;  June  30,  1922. 

70%  white  clover  seed. 

20%  white  clover  tops. 

10%  grasses. 
Stomach  No.  23 — female;   Iowa  City,  Iowa;   June  30,  1922. 

30%  insects. 

40%  white  clover  seed. 

30%  grass  and  white  clover  tops. 
Stomach  No.  24 — male;  North  Liberty,  Iowa;  July  3,  1922. 

Contained  two  young  meadow  mice. 
Stomach  No.   25 — female;    North  Liberty,  Iowa;   July  3,   1922. 

35%  insect  matter. 

10%  white  clover  seed. 

50%  blue  grass  and  clover. 
5%  unidentified. 
Stomach  No.  26 — male;  North  Liberty,  Iowa;  July  3,  1922. 

Practically  empty.     A  few  white  clover  seeds  were  found. 
Stomach  No.   27 — male;    Iowa   City,   Iowa;    July   7,   1922. 

60%   unidentified  insect  materials. 

30%  grasshoppers. 

10%  blue  grass,  white  clover,  and  white  clover  seed. 
Stomach  No.  28 — male;  Midriver,  Iowa;  July  10,  1922. 

10%  grasshoppers. 

20%   other  insects. 

30%  white  clover  seed. 

30%  white  clover  and  blue  grass. 

10%   unidentified. 
Stomach  No.  29 — female;  Midriver,  Iowa;  July  10,  1922. 

90%  blue  grass. 

10%  white  closer  seed  and  some  weed  seed. 
Stomach  No.  30 — female;  Midriver,  Iowa;  July  10,  1922. 

75%  blue  grass. 

10%  white  clover  seed. 

15%  weed  seeds. 
Stomach  No.  31 — male;  Iowa  City,  Iowa;  July  24,  1922. 

20%  grasshoppers. 

30%  white  clover  seed. 

10%  various  seeds. 

30%  blue  grass. 

10%  unidentified  (some  insect  remains). 


CITELLUS  TRIDECEMLINBATUS  31 

Stomach  No.  32 — male;   Iowa  City,  Iowa;  July  24,  1922. 

10%   grasshoppers. 

20%   unidentified  insects. 

20%  various  weed  seeds. 

10%  oats. 

40%  blue  grass. 
Stomach  No.  33 — male;   Iowa  City,  Iowa;   August  6,   1922. 

95%  grasshoppers. 
5%  unidentified  materials. 
Stomach  No.  34 — female;   Iowa  City,  Iowa;  August  6,  1922. 

Entirely  filled  with  grasshoppers. 
Stomach  No.  35 — male;   Victor,  Iowa;   August  7,   1922. 

90%  grasshoppers. 

10%  grass  and  unidentified  materials. 
Stomach  No.  36 — male;  Victor,  Iowa;  August  7,  1922. 

90%   grass  and  white  clover. 
5%  white  clover  seed. 
5%  unidentified. 
Stomach  No.  37 — male;  Victor,  Iowa;  August  7,  1922. 

Contained  one  small  field  mouse. 
Stomach  No.  38 — female;   Iowa  City,  Iowa;   August  16,  1922. 

Entirely  filled  with  grasshoppers. 
Stomach  No.  39 — female;   Iowa  City,  Iowa;   August  16,  1922. 

60%  grasshoppers. 

40%  grass  and  clover  leaves. 
Stomach  No.  40 — male;  North  Liberty,  Iowa;  August  17,  1922. 

Entirely  filled  with  grasshoppers. 
Stomach  No.  41 — female;  North  Liberty,  Iowa;  August  17,  1922. 

Entirely  filled  with  grasshoppers. 
Stomach  No.  42 — male;   North  Liberty,  Iowa;   August  17,  1922. 

10%  grasshoppers. 

90%  young  oats. 
Stomach  No.  43 — male;  North  Liberty,  Iowa;  August  17,  1922. 

Practically  empty.     Some  traces  of  grass  were  found. 
Stomach  No.  44 — male;   Iowa  City,  Iowa;   August  18,  1922. 

90%  grasshoppers. 

10%  white  clover. 
Stomach  No.  45 — female;  Iowa  City,  Iowa;  August  18,  1922. 

Almost  empty.     A  few  grasshopper  remnants. 
Stomach  No.  46 — male;  Iowa  City,  Iowa;  August  19,  1922. 

60%  grasshoppers. 

40%  grass  and  clover. 
Stomach  No.  47 — male;  Lake  Okoboji,  Iowa;   September  4,  1922. 

40%  grasshoppers. 

20%  other  insects. 

30%  corn. 

10%  weed  seed. 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

Stomach  No.  48 — male;  Lake  Okoboji,  Iowa;   September  4,  1922. 

60%  grasshoppers. 
40%  grass  and  clover. 
Stomach  No.  49 — female;  Lake  Okoboji,  Iowa;  September  4,  1922. 

Practically  full  of  new  corn. 
Stomach  No.   50 — male;    Lake  Okoboji,   Iowa;    September   4,   1922. 

60%  grasshoppers. 

40%  new  corn. 
Stomach  No.  51 — female;  Lake  Okoboji,  Iowa;   September  4,  1922. 

Full  of  new  corn. 
Stomach  No.  52 — female;   Lake  Okoboji,  Iowa;   September  8,  1922. 

30%   grasshoppers. 

60%  corn. 

10%  unidentified. 
Stomach  No.  53 — male;  Lake  Okoboji,  Iowa;   September  8,  1922. 

Practically  full  of  grasshoppers. 
Stomach  No.  54 — female;   Lake  Okoboji,  Iowa;   September  8,  1922. 

Practically  full  of  grasshoppers. 
Stomach  No.  55 — male;   Milford,  Iowa;   September  10,  1922. 

90%   grasshoppers. 

10%  corn. 
Stomach  No.  56 — male;   Spencer,  Iowa;  September  10,  1922. 

A  few  grasshoppers. 
Stomach  No.  57 — male;   Iowa  City,  Iowa;   May  14,  1923. 

About  a  quarter  full  of  oats. 
Stomach  No.  58 — female;  Iowa  City,  Iowa;  May  14,  1923. 

A  few  hulls  of  corn  were  found  in  this  specimen. 
Stomach  No.  59 — female;   Iowa   City,  Iowa;    May  15,  1923. 

60%  insect  larvae. 

40%  grass. 
Stomach  No.  60 — male;   Iowa  City,  Iowa;   May  16,  1923. 

90%  grass. 

10%  weed  seeds. 
Stomach  No.  61 — male;  West  Branch,  Iowa;  May  20,  1923. 

10%  insect  remains. 

80%  weed  seeds. 

10%  unidentified. 
Stomach  No.  62 — female;   Iowa  City,  Iowa;   June  10,  1923. 

10%   insect   remains. 

40%  white  clover  stems. 

50%  weed  seeds. 
Stomach  No.   63 — male;    Iowa   City,  Iowa;   June   10,  1923. 

90%  grass  and  white  clover. 

10%  weed  seeds. 
Stomach  No.  64 — male;   Millersburg,  Iowa;   June  12,   1923. 

Half  full  of  unidentifiable  insect  remains. 
Stomach  No.  65 — female;   Millersburg,  Iowa;   June  12,  1923. 

Half  full  of  insect  remains. 


CITELLUS  TRIDECEMLINBATUS  33 

Stomach  No.  66 — male;  Columbus  Junction,  Iowa;  June  20,  1923. 

40%  insect  remains. 

10%  grass. 

30%  weed  seeds. 
Stomach  No.  67 — female;  Iowa  City,  Iowa;  June  26,  1923. 

70%  unidentified  insect  matter. 

20%   grass. 

10%  clover  seed. 
Stomach  No.  68 — male;  Iowa  City,  Iowa;  June  29,  1923. 

20%   unidentified  insects. 

10%  grasshoppers. 

40%   grass  and  clover. 

30%  white  clover  seed. 
Stomach  No.  69 — male;  Iowa  City,  Iowa;   June  29,  1923. 

20%  insects. 

60%  grass. 

20%  white  clover  seed. 
Stomach  No.  70 — female;  Hidriver,  Iowa;  July  3,  1923. 

Half  full  of  white  clover  seed. 
Stomach  No.   71 — female;   Midriver,  Iowa;   July  3,   1923. 

10%  insects. 

00%  white  clover  seed. 
Stomach  No.  72 — male;  Marengo,  Iowa;  July  12,  1923. 

40%   grasshoppers. 

40%   grass. 

20%  clover  seed. 
Stomach  No.  73 — male;  Marengo,  Iowa;  July  12,  1923. 

A   few   grasshoper   remnants. 
Stomach  No.  74— female;  Iowa  City,  Iowa;  July  30,  1923. 

90%  grasshoppers. 
5%  grass  and  clover. 
5%  unidentified. 
Stomach  No.  75 — male;  Iowa  City,  Iowa;  August  2,  1923. 

60%  grasshoppers. 

30%  seeds,  (mainly  white  clover). 

10%  unidentified  material. 
Stomach  No.  76 — male;  Iowa  City,  Iowa;  August,  1923. 

60%   grasshoppers. 

20%  new  corn. 

20%  clover  seed. 
Stomach  No.  77 — male;   Iowa  City,  Iowa;  August  9,  1923. 

20%  unidentified  insects. 

80%  grass  and  white  clover  stems. 
Stomach  No.   78 — female;    Brooklyn,  Iowa;   August  10,   1923. 

Half  full  of  small  grasshoppers. 
Stomach  No.   79 — male;    Brooklyn,  Iowa;   August   10,   1923. 

A  few  grasshopper  remains. 


34  IOWA  STUDIES  IN  NATURAL  HISTORY 

Stomach  No.  80 — male;   Colfax,  Iowa;   August  11,  1923. 

30%  grasshoppers. 

70%  oats. 
Stomach  No.  81 — female;  Iowa  City,  Iowa;   September  2,  1923. 

70%  grasshoppers. 

30%  grass  and  white  clover. 
Stomach   No.   82 — female;    Iowa   City,   Iowa;    September   2,    1923. 

A  few  grasshopper  remains. 


NATURAL  ENEMIES  AND  ARTIFICIAL  CONTROL 

NATURAL  ENEMIES 

As  natural  enemies  of  Citellus  tridecemlineatus  tridecemlineatus 
some  of  the  common  hawks  should  receive  special  mention.  The 
writer  observed  one  instance  where  a  Cooper's  Hawk  practically 
exterminated  the  ground  squirrels  of  an  upland  pasture.  The  Red- 
tailed  Hawk  and  its  varieties  are  persistent  enemies  of  the  sper- 
mophile.  Sharp-shinned  Hawks,  Marsh  Hawks  and  Sparrow 
Hawks  have  been  seen  to  attack  this  species. 

The  domestic  cat  should  probably  rank  second  as  an  agency  in 
control.  Certain  cats  seem  to  acquire  a  special  liking  for  ground 
squirrels  and  become  exceedingly  adept  at  catching  them. 

Snakes  kill  considerable  numbers  of  spermophiles.  Bull  snakes, 
blue-racers,  hog-nosed  snakes  and  occasionally  garter  snakes  figure 
in  this  capacity. 

Weasels  and  the  smaller  mink  are  effective  enemies  of  the  ground 
squirrel.  Although  they  hunt  principally  at  night,  their  slender 
forms  permit  them  to  enter  many  of  the  spermophile  burrows  with 
ease.  There  is  no  doubt  that  many  ground  squirrels  meet  death 
through  these  night  attacks. 

Wolves,  foxes  and  eagles  destroy  ground  squirrels,  but  in  Iowa, 
at  least,  these  animals  are  not  present  in  sufficient  numbers  to 
serve  as  potent  controlling  factors. 

Perhaps  skunks  and  owls  should  be  mentioned.  But  all  of  the 
species  belonging  to  these  groups  are  inclined  to  be  nocturnal  or 
crepuscular  and  do  not  come  in  contact  with  the  strictly  diurnal 
spermophiles  very  frequently. 

External  parasites  are  rather  uncommon  on  Citellus  tridecem- 
lineatus tridecemlineatus.  All  of  the  individuals  killed  or  trapped 
were  carefully  examined  and  in  only  a  few  cases  were  any  para- 
sites found.  All  of  these  were  discovered  during  the  latter  part 
of  April  or  early  in  May,  just  after  the  animals  came  out  of  hiber- 
nation. No  parasites  were  found  after  May  fifteenth,  indicating 
that  the  spermophiles  are  able  to  dispose  of  the  pests  when  they 
resume  active  life. 

Over  half  of  the  parasites  found  were  fleas.     All  of  them  be- 

35 


36  IOWA  STUDIES  IN  NATUEAL  HISTORY 

longed  to  the  family  Pulicidae.    F.  C.  Bishopp  (1915,  p.  12)  enum- 
erates the  fleas  found  on  American  ground  squirrels  as  follows : 

The  Indian  rat  flea — Xenopsylla  cheopis  Eoth. 

The  European  rat  flea — Ceratophyllus  fasciatus  Bosc. 

The  human  flea — Pulex  irritans  L. 

The  European  mouse  flea — Leptopsylla  musculi  Duges. 

The  dog  flea — Ctenocephalus  canis  Curtis. 

The    squirrel    fleas — Hoplopsyllus    anomalus     Baker     and     Ceratophyllus 
acutus  Baker. 

The  cat  flea — Ctenocephalus  felis  Bouche. 
All  of  these  fleas  are  parasitic  on  rats  and  other  animals,  in- 
cluding man.  Some  are  known  to  carry  the  bubonic  plague  if  there 
is  a  source  of  infection.  The  California  ground  squirrel  (Citellus 
beecheyi  beecheyi)  was  discovered  as  an  agent  in  the  transmissal  of 
this  disease,  through  the  medium  of  parasitic  fleas.  (Lantz,  1921, 
pp.  12-13).  It  has  been  found  necessary  in  the  interests  of  human 
health  to  destroy  large  numbers  of  California  Ground  Squirrels 
over  infected  areas. 

It  is  not  beyond  possibility  that  Citellus  tridecemlineatus  tride- 
cemhneatus  might  aid  indirectly  in  the  spreading  of  similar  in- 
fections, either  now  or  in  the  future.  But  the  inconsiderable  num- 
bers of  parasites  found  on  this  species  precludes  the  possibility  that 
it  will  ever  be  a  dangerous  factor  in  human  environment.  At  any 
rate,  the  same  potential  possibility  occurs  among  man's  domestic 
animals,  whose  infection-carrying  parasites  are  legion  compared 
with  those  of  the  spermophile. 

In  one  case  a  mosquito  was  found  upon  the  body  of  a  Thirteen- 
lined  Spermophile.  Two  small  flies  were  likewise  found. 
Several  arachnids  belonging  to  the  family  Ixodidae  were  found 
clinging  to  the  spermophiles.  These  ticks  were  the  only  parasites 
of  importance  noted,  excepting  of  course,  the  fleas.  Ticks,  like 
fleas,  are  concerned  in  transmitting  a  parasite  from  the  blood  of 
one  animal  to  that  of  another.  A  tick-borne  parasite  is  Piroplasma 
bigeminum,  responsible  for  the  stock  disease  known  as  Texas  fever. 
The  ticks  found  on  the  spermophiles  of  the  upper  Mississippi  Valley 
are  probably  non-injurious  in  this  connection,  although  the  po- 
tential possibility  of  spreading  disease  exists. 

CONTROL  MEASURES 
When  Thirteen-lined  Spermophiles  become  so  thick  in  a  given 
locality  as  to  actually  menace  young  crops,  active  control  measures 
are  of  course  desirable. 


CITELLUS  TRIDECEMLINE ATUS  37 

The  damage  is  only  noticeable  in  the  spring  and  this  is  the  most 
opportune  time  to  apply  the  remedy,  for  in  the  spring  the  range 
of  the  spermophile  is  more  restricted  than  later  in  the  season,  and 
killing  the  adults  at  this  time  forestalls  reproduction. 

The  use  of  poisoned  baits  is  a  quick  and  efficient  method  for  de- 
stroying these  animals.  The  baits  should  always  be  placed  in  the 
entrances  of  the  burrows.  Otherwise  they  would  undoubtedly  be 
eaten  by  useful  species,  both  wild  and  domestic. 

D.  E.  Lantz  (1921,  p.  15)  gives  the  following  formula  for  poi- 
soning the  smaller  ground  squirrels:  "Mix  1  tablespoonful  of 
laundry  starch  in  y2  teacup  of  cold  water,  and  stir  it  into  ^2  P*11* 
of  boiling  water  to  make  a  thin  clear  mucilage.  Mix  1  ounce  of 
powdered  strychnine  with  1  ounce  of  powdered  bicarbonate  of 
soda,  and  stir  the  mixture  into  the  hot  starch,  making  a  smooth, 
creamy  paste  free  from  lumps.  Stir  in  y±  pint  of  heavy  corn 
syrup  and  1  tablespoonful  of  glycerin,  and  finally,  1  scant  tea- 
spoonful  of  saccharin.  Apply  to  20  quarts  of  oats,  and  mix  thor- 
oughly to  coat  every  kernel.  Each  quart  of  the  poisoned  grain 
should  make  forty  to  sixty  baits/ ' 

A  similar  formula  is  given  by  W.  L.  Burnett  (1914,  p.  15)  : 

Whole   corn   16   quarts 

Powdered  strychnine 1  ounce 

Saccharine    1    teaspoonful 

Flour  %   pint 

Salt  1   quart 

Water 1  quart 

As  in  the  preceding  case,  the  poison  mixture  is  poured  over  the 
grain.  Burnett's  experiments  showed  that  one  or  two  poisoned  ker- 
nels would  kill  a  spermophile. 

A  slightly  different  but  very  effective  method  of  exterminating 
the  animals  is  carbon  bisulphid,  poured  on  balls  of  cotton,  which 
are  then  pushed  down  the  mouth  of  the  burrow.  The  openings  of 
the  burrow  are  then  closed.  The  carbon  bisulphid  will  evaporate 
rapidly,  and  the  spermophiles  will  be  killed  by  the  poisonous  fumes. 
This  method  has  the  advantage  that  there  is  no  chance  of  poisoning 
other  animals  unintentionally  through  its  practice.  It  must  be  re- 
membered that  carbon  disulphid  is  a  highly  explosive  liquid  and 
should  not  be  handled  near  a  fire  or  by  an  individual  who  is 
smoking. 

Often  considerable  numbers  of  spermophiles  may  be  killed  by 
shooting  them  with  a  small-bore  rifle.    This  requires  accurate  shoot- 


38  IOWA  STUDIES  IN  NATUEAL  HISTORY 

ing  and  considerable  effort  and  patience  on  the  part  of  the  hunter. 
Unless  the  ground  squirrels  are  shot  through  the  head  or  thorax 
they  will  crawl  into  their  holes  to  die  a  lingering  death. 

Trapping  is  a  still  more  unsatisfactory  method.  A  number  0 
or  number  1  steel  trap  may  be  used  to  catch  this  species.  Simply 
hollow  out  a  cavity  at  the  mouth  of  the  burrow  for  the  trap  to  rest 
in,  and  cover  the  set  lightly  with  dirt.  This  means  of  extermination 
is  not  recommended  because  so  many  spermophiles  escape  after 
having  their  feet  cut  off. 

On  the  whole,  poisoning  is  much  to  be  preferred.  It  is  simple, 
fairly  safe,  and  does  not  require  as  much  time  and  effort  as  the 
other  methods.    Besides,  the  results  are  immediate  and  pronounced. 


BIBLIOGEAPHY 

Aldrich,  J.  M.,  Food  Habits  of  the  Striped  Gopher,  So.  Dak.  Agr.  Coll.  and 
Exp.  Sta.,  Bull.  No.  30,  1892. 

Audubon,  J.  J.,  and  Baehman,  J.,  The  Quadrupeds  of  North  America,  Vol. 
I,  1894,  177. 

Bailey,  Vernon,  Article  on  Spermophilus  tridecemlineatus,  Ann.  Eept.  TJ.  S. 
Dept.  Agr.,  1887,  437. 

Bailey,  Vernon,  Article  on  Spermophilus  tridecemlineatus,  U.  S.  Dept.  Agr., 
Bull.  No.  4,  1893,  43. 

Baird,  S.  F.,  Mammals  of  North  America,  1859,  316-319. 

Bell,  Wm.  B.,  and  Piper,  S.  E.,  Extermination  of  Ground  Squirrels,  Gophers, 
and  Prairie  Dogs  in  North  Dakota,  No.  Dak.  Agr.  Sta.  Circ,  4,  1915. 

Bishopp,  F.  C,  Fleas,  U.  S.  Dept.  Agr.,  Bull.  No.  248,   1915,  11-15. 

Burnett,  W.  L.,  The  Striped  Ground  Squirrels  of  Colorado,  Offiee  State  En- 
tomologist, Circ.  14,  1914. 

Cory,  C.  B.,  Mammals  of  Illinois  and  Wisconsin,  Field  Mus.  Nat.  Hist.  Zool, 
Ser.,  Vol.  XI,  1912,  138. 

Coues,  E.,  and  Allen,  J.  A.,  Monograph  of  North  American  Bodentia,  Kept- 
U.  S.  Geol.  Surv.,  Vol.  XI,  1887,  871. 

Elliott,  D.  G.,  A  Synopsis  of  the  Mammals  of  North  America  and  the  Adja- 
cent Seas,  Field  Columbian  Mus.  Zool.  Ser.,  Vol.  II,  1901,  100. 

Elliott,  D.  G.,  A  Checklist  of  the  Mammals  of  the  North  American  Conti- 
nent, the  West  Indies  and  the  Neighboring  Seas,  Field  Columbian  Mus. 
Pub.   105,  1905,   104. 

Flower,  W.  H.,  and  Lydekker,  B.,  An  Introduction  to  the  Study  of  Mammals 
Living  and  Extinct,  1891,  156. 

Gillette,  C.  P.,  Food  Habits  of  the  Striped  Prairie  Squirrel,  la.  Agr.  Exp. 
Sta.,  Bull.  No.  6,  1889. 

Goodrich,  S.  A.,  Illustrated  History  of  the  Animal  Kingdom,  1859,  364. 

Herrick,  C.  L.,  The  Mammals  of  Minnesota,  Geol.  and  Nat.  Hist.  Surv.  Minn., 
Bull.  No.  7,  1892,  165. 

Hornaday,  W.  T.,  The  American  Natural  History,  1904,  94. 

Hornaday,  W.  T.,  The  American  Natural  History,  Vol.  I,  1914,  197. 

Hoy,  P.  R.,  Hibernation  of  Spermophilus  tridecemlineatus,  Proc.  Amer.  Assoc. 
Adv.  Sci.,  Aug.  1875,  148. 

Johnson,  G.  E.,  The  Habits  of  the  Thirteen-lined  Ground  Squirrel,  Quart. 
Journ.  Univ.   of  No.  Dak.,   Vol,  VII,  No.  3,  Apr.   1917,  261. 

Kingsley,  J.  S.,  The  Standard  Natural  History,  Vol.  V,  1886,  125. 

Lantz,  D.  E.,  Rodent  Pests  on  the  Farm,  Farmers  Bull.  932,  TJ.  S.  Dept.  Agr., 
1921,  11. 

Lee,  T.  G.,  Implantation  of  the  Ovum  in  Spermophilus  tridecemlineatus,  Mark 
Anniversary  Volume,  Seience,  1902,  417. 

39 


40  IOWA  STUDIES  IN  NATURAL  HISTORY 

Lee,   T.   G.,   On  the  Early  Development   of   Spermophilus   tridecemlineatus,  a 

New  Type  of  Mammalian  Placentation,  Science,  N.  Ser.,  Vol.  XV,  No. 

379,  1902a,  525. 
Kiehardson,   J.,    (Swainson   and    Kirby),    Fauna    Boreali   Americana    or    The 

Zoology  of  the  Northern  Parts  of  British  America,  1892,  177. 
Seton,  E.   T.,  Citellus  tridecemlineatus,  Life  Histories  of  Northern  Animals, 

Vol.  I,  394. 
Stone,  W.,  and  Cram,  W.   E.,  American  Animals,   1905,   161. 
Stoner,  Dayton,  The  Rodents  of  Iowa,  la.  Geol.  Surv.  Bull.  No.  5,  1918,  29. 
Tenney,  Sanborn,  A  Manual  of  Zoology,   1882,  91. 
U.  S.  Department  of  Agriculture,  Directions  for  Poisoning  Ground  Squirrels, 

Form  Bi-176,  1918. 
Warren,  E.  R.,  The  Mammals  of  Colorado,  1910,  159. 
Wood,   F.   E.,   Mammals   of   Champaign   County,   Illinois,   Bull.   111.   St.   Lab. 

Nat.  Hist.,  May,  1910,  524. 


PLATE  I 


6  in. 


10  in. 


It  tn.  12.  in. 


Temporary  burrows 


PLATE  II 


xo 


IS 


ZO 


19 


16 


8 


J4 


19 


Temporary  burrows 


PLATE  III 


Permanent  burrow 


PLATE  IV 


Permanent  burrows 


PLATE  V 


IA& 


June  J^y  *u<3-         Sept. 


Food  chart 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 

Henry  Frederick  Wickham,  Editor 
VOLUME  XI  NUMBER  2 

THE  LIFE  HISTORY  AND  BIONOMICS  OF 

APHIS  RUMICIS 

by 
John  Louis  Horsfall  j 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


J*-*«- 


INTBODUCTION 

The  identity  of  Aphis  rumicis  Linn,  has  been  of  interest  to 
aphidologists  in  various  countries  for  many  years.  The  early 
practice  of  naming  species  of  aphids  from  the  host  plants  upon 
which  they  commonly  occurred,  while  of  value  to  a  large  extent 
in  aiding  in  the  future  recognition  of  the  species,  resulted  in  some 
cases  in  the  making  of  synonyms.  With  the  advent  of  careful 
life  history  studies  and  the  recognition  of  the  fact  that  aphids 
may  select  plants  widely  removed  botanically  from  their  summer 
hosts  upon  which  to  hibernate,  the  synonymy  of  many  aphids 
has  been  worked  out  with  more  certainty.  In  the  case  of  Aphis 
rumicis  Linn.,  we  find  that  forms  occurring  on  different  host  plants 
were  described  as  separate  species  when,  in  many  instances,  the 
only  differentiating  character  given  by  the  author  was  the  general 
body  color,  a  character  which  is  of  little  specific  value,  in  the 
tribe  Aphidini  as  a  whole,  in  separating  closely  related  species. 

I  have  pursued  detailed  studies  on  the  biology  of  this  species 
during  four  seasons  and  from  these  data  have  secured  definite 
evidence  on  the  identity  of  forms  occurring  on  widely  dissociated 
species  of  host  plants  at  different  periods  during  the  year.  Al- 
though the  number  of  food  plants  reported  for  Aphis  rumicis  is 
extremely  large,  nine  additional  species  are  given  in  these  studies. 
Detailed  life  history  studies  and  generation  experiments  are  re- 
ported for  the  first  time.  Among  the  records  of  natural  enemies 
will  be  found  the  names  of  several  interesting  forms  not,  as  yet, 
connected  with  Aphis  rumicis  in  literature.  My  own  material  has 
been  collected  in  Iowa  and  Eastern  Pennsylvania.  The  English 
material  was  obtained  through  the  courtesy  of  Professor  F.  V. 
Theobald,  and  the  California  specimens,  representing  collections 
of  Swain  and  Davidson,  were  kindly  loaned  by  Professor  G.  F. 
Ferris  of  Stanford  University.  I  wish  to  express  my  appreciation 
to  Professor  H.  F.  Wiekham,  State  University  of  Iowa,  for  his 
valuable  criticism  in  the  preparation  of  these  studies,  to  Dr.  A. 
C.  Baker,  Bureau  of  Entomology,  United  States  Department  of 
Agriculture,  for  his  suggestions  while  I  was  examining  material  in 
the  collection  of  the  Bureau  and  the  notes  of  Dr.  Asa  Fitch  and 

3 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

Mr.  Theo.  Pergande,  and  to  Messrs.  A.  B.  Gahan  and  H.  E.  Ewing 
of  the  United  States  National  Museum  for  their  determinations  of 
parasitic  material. 

PEEVIOUS  WORK  ON  THE  PROBLEM 

For  a  century  and  a  half  after  publication  of  the  original  de- 
scription of  Aphis  rumicis  by  Linnaeus,  all  printed  references  re- 
lated to  its  occurrence  in  different  localities  on  various  host  plants 
with  occasional  descriptions  of  the  summer  forms.  The  first  record 
of  biological  observations  on  the  species,  which  has  come  to  my 
attention,  was  published  by  Walker  (97)  who  noted  the  fact  that 
this  aphid  hibernated  on  the  common  furze.  Buckton  (2)  made 
transfers  from  foxglove  to  common  broom  with  negative  results. 

Biological  observations  of  a  detailed  nature  were  published  by 
Theobald  (88),  in  1912,  and  were  based  on  collections  and  notes 
from  England  and  on  other  European  material.  He  outlined  two 
cycles:  one  starting  with  ova  and  fundatrices  on  Euonymus 
europceus  and  migrating  to  poppies,  mangolds,  dahlias,  etc.  for  the 
summer  generations;  the  other  starting  on  dock  and  migrating  to 
broad  beans  for  the  summer.  Theobald's  statements  indicate  that 
he  depended  mainly  upon  structural  characters  to  determine  the 
identity  of  the  forms  occurring  on  the  winter  and  summer  hosts. 
He  gave  the  specific  names  which  he  considered  to  be  definitely 
established  as  synonyms,  as  well  as  other  possible  synonyms,  a 
comprehensive  list  of  food  plants,  descriptions  of  the  apterous 
viviparous  female,  the  nymph,  and  the  winged  viviparous  female. 
He  also  called  attention  to  the  differences  in  color  of  similar  forms 
on  different  hosts  and  to  differences  in  number  of  antennal  sensoria 
in  the  winged  viviparous  female. 

In  America,  scarcely  any  biological  observations  of  Aphis 
rumicis  founded  upon  experimental  data  have  been  published. 
Osborn  and  Sirrine  (65)  by  means  of  transfer  tests  established 
the  cycle  from  Euonymus  to  some  of  the  summer  food  plants. 
Ohlendorff  (62)  in  an  unpublished  manuscript  outlined  the  first 
born  generation  series  on  Euonymus  europceus  and  Viburnum 
opulus  for  one  season,  a  description  of  forms,  and  a  limited  number 
of  transfer  tests  which  have  been  discussed  in  another  section  of 
this  paper. 

In  England,  Davidson  (15-20)  has  recently  published  a  series 
of  papers  dealing  with  several  phases  of  the  biology  of  Aphis 
rumicis.     His  studies  include   a  short  description  of  the  adult 


APHIS  RUMICIS  5 

forms,  a  generalized  life-cycle  with  Euonymus  as  the  winter  host, 
detailed  transfer  experiments  on  many  varieties  of  beans,  rearings 
to  determine  causal  factors  which  determine  the  appearance  of 
winged  forms  and  sexes,  and  a  study  of  the  sources  of  food  supply 
in  the  plant  tissues. 

Attention  is  called  to  the  fact  that  this  paper  presents  the  first 
published  record  of  detailed  life  history  data,  including  first-born 
series,  the  detailed  information  on  reproduction  derived  from  these 
records,  and  the  complete  life-cycle  on  herbaceous  plants.  Prac- 
tically all  of  the  transfers  presented  are  new  since  they  include 
the  common  hosts  of  Aphis  rumicis  in  the  Eastern  and  Central 
United  States. 

ECONOMIC  HISTORY  AND  DISTRIBUTION 

In  Foreign  Countries :  Evidently  the  first  mention  of  this  aphid 
as  an  insect  of  economic  importance  was  by  Scopoli  (79)  who,  in 
1763,  noted  the  fact  that  colonies  of  Aphis  fabce  rendered  the 
broad  bean,  Vicia  faba,  sterile.  Other  early  European  entomolo- 
gists included  it  under  the  name  of  Aphis  rumicis  or  one  of  the 
numerous  synonyms  in  their  lists,  but  made  no  particular  refer- 
ence to  it  as  a  pest  upon  plants  of  economic  importance.  In  1815, 
Kirby  and  Spence  (48)  called  attention  to  it,  under  the  name  of 
Aphis  fabce,  as  a  pest  on  beans.  Curtis  (13),  in  1860,  gave  an 
interesting  account  of  the  ravages  of  Aphis  rumicis  as  follows: 
"In  1833,  the  beans  were  almost  totally  destroyed  in  Yorkshire. 
In  1841,  they  (the  aphids)  were  abundant  in  my  garden  near  the 
Regents'  Park ;  but  in  1842  I  never  saw  one  on  the  spot,  yet  the 
beans  around  Sandgate  in  the  same  year  were  very  much  injured 
by  them.  On  the  5th  of  June,  1846,  I  could  only  find  apterous 
specimens  on  broad  bean  tops;  but  on  the  11th  I  detected  some 
winged  specimens  and  the  beans  in  the  potato  rows  were  smothered 
with  them,  whilst  those  in  a  separate  bed  were  free  and  by  topping 
them  the  crop  escaped." 

Buckton  (2)  spoke  of  the  common  names,  collier  and  black 
dolphin,  given  to  this  aphid  by  the  "rustics".  He  said,  "the 
stalks  of  the  broad  bean  also  are  very  liable  to  be  similarly  en- 
crusted by  them,  and  then  both  the  garden  and  the  field  crops  are 
totally  destroyed.  In  1854,  its  ravages  in  the  turnip  fields  of 
Yorkshire  were  very  marked,  many  hundred  acres  being  entirely 
ruined."  Theobald  (88)  said  that  in  England  Aphis  rumicis  is 
best  known  as  a  bean  and  mangold  pest.    He  spoke  of  the  fact  that 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  numerous  individuals  frequently  swarmed  over  the  young  pods 
of  the  broad  bean  and  destroyed  them.  He  recorded  the  fact  that 
he  had  seen  whole  beds  of  Shirley  poppies,  and  also  the  tops  of 
onions  and  leeks  killed  by  this  aphid. 

In  America :  Aphis  rumicis  is  generally  considered  to  be  indig- 
enous to  the  Old  World.  We  have  no  data  which  give  us  any 
hint  as  to  the  date  of  its  introduction  into  America.  Pitch  (32), 
in  1870,  included  Aphis  rumicis  among  the  injurious  insects  re- 
ported from  New  York.  An  unpublished  note  by  Dr.  Pitch  (33), 
telling  of  injury  to  Euonymus,  is  of  interest  in  this  connection: 
He  wrote  as  follows:  "Aphis  evonymi  Pab.  Trees  killed  by  it — 
July  9,  1873. — A  spindle  tree  in  my  front  yard  had  every  leaf 
upon  it  withered  and  the  tree  died  over  a  month  ago.  A  large 
spindle  tree  in  front  of  Judge  Allen's  house  in  Salem  village, 
some  12  feet  high  with  large  spreading  limbs,  has  its  leaves  mostly 
dropped  off  and  the  few  remaining  ones  rolled  up  and  wilted  past 
recovery,  and  the  tree  is  killed  beyond  hope  of  its  surviving  this 
disaster.' '  Thomas  (93)  gave  the  synonymy,  food  plants  then 
reported,  and  a  description  of  the  viviparous  forms  in  his  eighth 
Illinois  report  for  1878.  The  species  was  not  listed  by  Riley  and 
Monell  (73),  in  1879,  as  having  been  taken  by  them  in  the  terri- 
tory west  of  the  Mississippi  River.  Oestlund  (60)  recorded  it 
from  Minnesota  in  1887,  as  occurring  on  Chenopodium  album  and 
Eumex  crispus,  and  in  1893  Osborn  and  Sirrine  (65)  described  its 
occurrence  on  Euonymus,  Dock,  and  Chenopodium  album.  In 
1895,  Gillette  and  Baker  (38)  listed  it  from  Colorado  on  Eumex 
crispus.  In  1908,  Sanderson  (75)  said,  "The  bean  aphis  caused 
injury  to  beans  in  Massachusetts  and  Wisconsin;  to  celery,  horse- 
radish, and  strawberries  in  California;  and  to  rhubarb,  beets  and 
broad  beans  in  New  Jersey".  Gillette  (37),  in  1910,  published 
collection  records  of  Aphis  rumicis  from  Oregon,  Illinois,  New 
York  and  Washington,  D.  C,  taken  on  Eumex  crispus,  garden 
beets,  yellow  dock,  burdock,  and  Chenopodium  album.  He  did 
not  speak  of  the  aphid  as  of  particular  economic  importance. 
Britton  (8)  in  1916,  stated  that  this  insect  had  caused  some  injury 
in  a  field  of  seed  beets  in  Connecticut.  The  infestation  was  chiefly 
around  the  edges  of  the  field  and  plants  of  Chenopodium  album 
along  the  borders  of  the  field  were  also  found  to  be  infested. 

Headlee  (44)  called  attention  to  an  outbreak  of  this  aphid  on 
beans  in  New  Jersey  in  1916.     Cory  (11),  in  1918,  said  that  it 


APHIS  EUMICIS  7 

was  a  serious  pest  in  places  on  bush  Lima  beans  in  Maryland,  and 
made  the  statement  that  the  species  migrated  from  snowball  to 
dock  in  the  spring.  He  gave  no  experimental  data  to  substantiate 
this  statement.  Orton  and  Chittenden  (64),  in  1917,  listed  this 
insect  as  a  pest  of  beans  in  all  parts  of  the  United  States,  espec- 
ially on  early  beans  in  California.  Other  workers  who  have  re- 
ported it  as  a  pest  on  beans  in  the  United  States  include  Smith  (8) 
in  Virginia,  Talbert  (86)  in  Missouri,  Stewart  (83)  in  Utah, 
.DeOng  (24),  Essig  (25),  and  Gilbert  and  Popenoe  (36)  in 
California. 

In  1905,  Fletcher  (34)  noted  the  fact  that  Aphis  rumicis  was 
a  serious  pest  on  horse  beans  in  Europe,  but  that  it  was  only  oc- 
casionally serious  in  Canada  since  the  crop  was  little  grown  there. 
Reports  in  1909  and  1917  by  Bethune  (5,  6)  tell  of  the  difficulty 
in  obtaining  satisfactory  crops  of  Windsor  Beans  and  horse  beans 
in  Canada  due  to  the  attacks  of  this  black  aphis.  Sanderson  (76), 
O'Kane  (63),  and  Crosby  and  Leonard  (12)  listed  this  aphid  as 
a  pest  of  beans  in  their  texts. 

The  following  observations  may  be  drawn  from  these  represent- 
ative reports  of  the  occurrence  of  Aphis  rumicis  in  Europe  and 
in  North  America.  The  earliest  records  give  various  indigenous 
weeds  and  shrubs  as  the  hosts  of  this  aphis.  Reports  indicating 
that  the  species  was  of  economic  importance  are  found  first  in 
European  literature  and  only  in  comparatively  recent  years  in 
North  America.  The  reports  of  severe  infestations  of  an  economic 
nature  in  North  America  have  .come  from  sections  of  the  country 
where  some  variety  of  beans  is  grown  as  a  staple  crop,  with  oc- 
casional reports  on  Euonymus. 

Distribution  records  include  England,  Italy,  France,  Belgium, 
Germany,  Holland,  Sweden,  Russia,  Egypt,  India,  Japan,  Formosa, 
Canada,  and  practically  all  of  the  United  States. 

SYNONYMY 

Aphis  rumicis  Linnaeus 

1758.     Aphis  rumicis  Linnaeus,  Syst.  Nat.,  Ed.  X,  I,  451. 
1746.     Aphis  rumicis  Linnaeus,  Fn.  Suec,  217. 
1758.    Aphis  craccce  Linnaeus,  Syst.  Nat.,  Ed.  X,  I,  452. 
1763.     Aphis  viburni  Scopoli,  Ent.  Cam.,  136. 
1763.     Aphis  fabce  Scopoli,  Ent.  Cam.,  139. 
1775.     Aphis  aparines  Fabricius,  Syst.  Ent.,  735, 
(nee  aparines  Fab.  Oestlund). 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

1775.    Aphis  euonymi  Fabricius,  Syst.  Ent.,  736. 

1775.  Aphis  atripUcis  Fabricius,  Syst.  Ent.,  737, 

(nee  atripUcis  Linn.). 

1776.  Aphis  papaveris  Fabricius,  Gen.  Ins.,  303. 
1781.    Aphis  vicice  Fabricius,  Spec.  Ins.,  II,  390. 

1801.  Aphis  thlaspeos  Schrank,  Fn.  Boic,  II,  118. 

1802.  Aphis  armata  Hausmann,  111.  Mag.,  I,  439. 
1841.  Cinaria  rumicis  Mosley,  Gard.  Chron.,  I,  747. 
1847.  Vibumifex  Amyot,  Ann.  Soc.  Ent.  Fr.,  2me. 

Serie,  V,  478. 
1847.    Evonymaphis  Amyot,  Ann.  Soc.  Ent.  Fr.,  2me. 

Serie,  V,  478. 
1847.    Rumicifex  Amyot,  Ann.  Soc.  Ent.  Fr.,  2me. 

Serie,  V,  478. 
1847.    Meconaphis  Amyot,  Ann.  Soc.  Ent.  Fr.,  2me. 

Serie,  V,  478. 
1847.     Craccifex  Amyot,  Ann.  Soc.  Ent.  Fr.,  2me. 

Serie,  V,  478. 
1852.    Aphis  hortensis  (Fab.)  Walker,  List  Homop. 

Brit.  Mus.,  IV,  981. 
1879.    Aphis  atripUcis  (Linn.)  Buckton,  (in  part),  Mon. 

Brit.  Aphides,  II,  87. 
1919.    Aphis  euonomi  (Fab.)  Swain,  U.  Calif.  Publ. 
Ent.,  Ill,  No.  1,  101. 
Aphis  rumicis  was  originally  named  and  described  by  Linnaeus 
in  1746,  in  his  first  edition  of  the  Fauna  Suecica  (49).    The  de- 
scription from  page  217  is  as  follows : 
708.     Aphis  Rumicis 

Habitat  in  Rumicibus  293.  295. 

Descr.    Corpus   nigro-seneum.   Antennae   nigrae  vel   albae 

apicibus  nigris.     Pedes  albidi  geniculis  nigris.     Cauda 

acuminato-cornuta.    Alarum  basis  virescens ;  Appendiculi 

atri,  filiformes,  longitudine  caudae. 

Linnaeus  did  not  repeat  this  description  in  Systema  Naturae, 

Edition  X,  1758   (50),  but  referred  to  the  description  in  Fauna 

Suecica.    He  also  listed  Aphis  craccce  in  Systema  Naturae,  Edition 

X,  but  the  description  of  the  species  was  published  in  Fauna 

Suecica,  Editio  Altera  Auctior,  1761  (51).    Kaltenbach  redescribed 

craccce  under  the  same  name  in  1843  (46).    After  an  examination 

of  the  material  determined  as  craccce  at  Washington  and  a  con- 


APHIS  RUMICIS  9 

sideration  of  the  original  description  and  that  of  Kaltenbach,  I 
have  placed  craccce  as  a  synonym  of  rumicis. 

Scopoli  (79),  in  1763,  described  a  black  aphid  from  Viburnum 
under  the  name  of  Aphis  viburni.  This  has  been  accepted  as  a 
distinct  species  by  most  workers,  but  Hunter  (42)  considered  it 
to  be  a  synonym  of  rumicis.  Although  Theobald  wrote  me  that 
rumicis  did  not  occur  on  Viburnum  opulus  in  England,  Mordwilko 
recorded  it  (evonymi)  from  Russia,  and  Passerini  listed  it 
(papaveris)  from  Italy  on  this  host.  In  America,  Essig,  Patch, 
and  Wilson  have  recorded  rumicis  from  Viburnum.  Essig  (25) 
published  the  following  note  in  reference  to  rumicis: — "H.  P. 
Wilson  believes  this  species  to  be  A.  viburni  Scop."  Kaltenbach 
stated  that  the  character  which  separated  viburni  from  rumicis 
(evonymi)  was  the  presence  of  a  row  of  marginal  spines  or  tuber- 
cles on  the  abdomen  of  the  larva  of  viburni,  which  were  absent  on 
evonymi,  but  that  the  winged  forms  of  the  two  species  could 
scarcely  be  distinguished.  This  character  is  hardly  of  specific 
value  since  I  have  found  wide  variation  in  the  number  and  promi- 
nence of  these  tubercles  on  larvae  of  rumicis  from  Viburnum, 
Rumex,  Arctium,  and  Tropceolum.  The  tubercles  on  segments  one 
and  seven  are  fairly  constant,  but  there  is  considerable  variation 
in  the  size  of  the  tubercles  on  the  intervening  segments.  Theobald 
(89)  and  Haviland  (41)  have  suggested  that  Aphis  grossularice 
Kalt.  may  be  viburni  Schr.,  but  this  is  hardly  the  case  since 
Kaltenbach 's  description  of  grossularice  calls  for  an  aphid  with 
cornicles  and  cauda  greenish-yellow,  while  in  viburni  they  should 
be  black.  After  a  consideration  of  my  results  from  transfer  tests 
and  cross-copulation  experiments,  and  the  examination  of  my  own 
material,  I  have  reached  the  conclusion  that  Scopoli  described  the 
spring  generations  of  Aphis  rumicis  on  one  of  its  primary  hosts 
and  therefore  I  have  included  viburni  as  a  synonym.  Scopoli  (79) 
also  described  forms  from  Vicia  faba  under  the  name  of  Aphis 
fabce.  Kaltenbach  and  Passerini  listed  fabce  as  synonymous  with 
A.  papaveris  which  is  considered  in  this  paper  to  be  a  synonym 
of  rumicis.  Schouteden,  Theobald  and  others  have  placed  fabce 
as  a  synonym  of  rumicis.  My  own  material  and  some  received 
from  Theobald  taken  on  Vicia  faba  is  most  certainly  rumicis. 

In  1775,  Fabricius  (28)  described,  as  new,  three  species  which 
are  now  considered  to  be  synonymous  with  Aphis  rumicis  by  many 
workers ;  i.  e.  Aphis  aparines  from  Galium  aparine,  Aphis  euonymi 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

from  Euonymus  europceus,  and  Aphis  atriplicis  on  Atriplex  hort- 
ensis.  I  have  concluded  that  Fabricius  in  his  original  description 
of  aparines  and  Schrank  in  a  later  description  referred  to  rumicis. 
Kaltenbach  incorrectly  credited  the  authorship  of  aparines  to 
Schrank  in  listing  it  as  a  synonym  of  A.  papaveris.  Later 
authors  evidently  followed  Kaltenbach  in  designating  Schrank 
as  the  author.  Schouteden  and  Theobald  listed  aparines  as 
a  synonym  of  rumicis.  I  found  the  following  in  an  unpublished 
note  by  Dr.  Asa  Fitch  (33).  "Specimens  taken  on  Galium  vines, 
side  of  meadows  on  under  side  of  leaves.  Nov.  1870,  is  not  this 
the  Aphis  rumicis  Linn.,  the  A.  aparines  Fab.,  the  A.  galii 
Schrank?  Dec.  8,  1870,  This  I  have  scarcely  a  doubt  is  the 
Rumicis."  Aphis  aparines  Fab.  of  Oestlund  is  evidently  a  distinct 
species  distinguished  from  rumicis  by  absence  of  tubercles  on  the 
prothorax  and  smaller  number  of  sensoria  on  the  antennae. 

I  have  taken  forms  in  spring  and  fall  on  two  species  of  Euony- 
mus which  fit  the  descriptions  of  A.  euonymi  Fab.  as  given  by 
Fabricius,  Schrank,  Koch,  and  Kaltenbach.  I  have  not  been  able 
to  separate  these  specimens  on  the  basis  of  structural  characters 
or  biology  from  forms  taken  on  the  same  dates  from  Viburnum 
opulus,  Chenopodium  album,  Rumex  crispus  and  other  host  plants 
of  A.  rumicis.  I  have  also  proven  to  my  own  satisfaction,  by 
numerous  transfers  and  cross-copulation  tests,  the  identity  of  the 
form  from  Euonymus  with  that  from  numerous  other  host  plants 
and  thus  regard  euonymi  as  synonymous  with  rumicis.  Fabricius 
described  Aphis  atriplicis  as  a  black  aphid  infesting  Atriplex 
hortensis.  Linnaeus  had  previously  used  the  name  atriplicis  for 
a  green  aphid  which  caused  the  leaves  of  Atriplex  to  roll  longi- 
tudinally and  form  boat-shaped  galls.  The  description  of  A. 
atriplicis  Fab.  agrees  with  that  for  A.  rumicis  Linn,  and  since 
rumicis  is  found  on  species  of  Atriplex  at  the  present  time,  I  have 
considered  atriplicis  Fab.  to  be  a  synonym. 

In  1776,  Fabricius  (29)  described  forms  from  Papaver  somni- 
ferum  as  Aphis  papaveris.  This  name  has  been  considered  to  be 
synonymous  with  rumicis  by  Schouteden,  van  der  Goot,  Theobald, 
and  others.  I  have  compared  material  from  England  and  Cali- 
fornia from  the  poppy  with  my  own  collections  of  Aphis  rumicis 
made  in  Pennsylvania  and  can  distinguish  no  more  than  seasonal 
differences.  Aphis  vicice  was  first  used  by  Fabricius  (30)  in  1781, 
but  he  credited  Linnaeus  with  the  authorship,  citing  Fauna  Suecica, 


APHIS  KUMICIS  11 

species  number  986.  This  citation  is  Aphis  craccce  Linn,  as  indi- 
cated by  Linnaeus'  practice  of  designating  the  name  of  the  species 
described  in  the  margin  of  the  page.  As  I  have  previously  indi- 
cated, A.  craccce  is  considered  to  be  a  synonym  of  A.  rumicis  and 
thus  A.  vicice  Fab.  also  goes  into  synonymy. 

I  have  followed  Schouteden,  Theobald,  and  others  in  listing 
Aphis  thlaspeos  Schrank  as  a  synonym  of  A.  rumicis  on  the  basis 
of  the  original  description  and  the  fact  that  rumicis  is  known  to 
occur  on  shepherd's  purse,  the  host  from  which  Schrank 's  material 
was  collected.  Schrank  (77)  called  attention  to  the  similarity  in 
appearance  of  thlaspeos  with  the  species  on  dock,  A.  rumicis,  al- 
though he  considered  them  to  be  distinct. 

Several  workers  have  placed  Aphis  armata  Hausm.  as  a  synonym 
of  rumicis.  After  a  careful  consideration  of  Hausmann's  original 
description  (40)  it  seems  certain  that  he  referred  to  A.  rumicis 
and  I  have  consequently  listed  armata  as  a  synonym.  Cinaria 
rumicis  Mosley  has  been  correctly  listed  by  various  authors  as 
synonymous  with  Aphis  rumicis.  Mosley  (57)  adopted  the  sug- 
gestion of  Curtis  and  used  the  name  Cinaria  for  a  section  of  the 
genus  Aphis. 

In  1847,  Amyot  (1)  proposed  as  new  names  for  A.  rumicis  and 
other  names  which  I  have  listed  as  synonyms,  Rumicifex,  Vibur- 
nifex,  Evonymaphis,  Meconaphis  and  Craccifex.  As  there  seem 
to  be  no  reasonable  grounds  for  making  such  a  change,  I  have 
considered  these  as  synonyms  of  A.  rumicis. 

Walker  (98)  listed  Aphis  hortensis  Fab.  as  a  synonym  of  rumi- 
cis, but  his  citation  refers  to  atriplicis  Fab.  Although  Fabricius 
wrote  the  name  Aphis  atriplicis  hortensis  at  the  beginning  of  the 
description,  he  designated  atriplicis  as  the  specific  name  in  the 
margin  according  to  his  usual  practice.  Since  atriplicis  Fab.  is  a 
synonym  of  rumicis,  A.  hortensis  Fab.  of  Walker  also  becomes  a 
synonym. 

Aphis  atriplicis  Linn,  of  Buckton  (2)  is  in  part  synonymous 
with  Aphis  rumicis.  His  descriptions  of  varieties  1»  and  2  of  the 
apterous  viviparous  female  and  that  of  the  winged  viviparous 
female  certainly  refer  to  rumicis  on  Chenopodium. 

Swain  (84),  in  1919,  published  excellent  descriptions  of  forms 
of  Aphis  rumicis  from  various  host  plants.  He  raised  the  question 
as  to  the  identity  of  A.  rumicis  Linn,  and  proposed  that  rumicis 
Linn,  of  American  and  late  European  workers  should  be  considered 
as  synonymous  with  Aphis  euonomi  Fab.    He  gives,  as  the  basis 


12 


IOWA  STUDIES  IN  NATURAL  HISTORY 


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APHIS  RUMICIS  13 

for  this  proposal,  the  distinction  as  to  host  plants  and  color  of  the 
winged  form.  I  have  quoted  the  original  description  of  Linnaeus 
in  which  it  will  be  noted  that  the  color  given  for  the  winged  form 
is  "black-bronze".  I  have  oftfen  taken  specimens  of  rumicis  on 
Rumex  which  exhibited  this  blackish-brassy  tinge  to  the  body  due 
to  the  obscure  dark  olive  cast  from  the  body  contents.  Nor  can  it 
hardly  be  argued  that  rumicis  of  American  authors  is  not  rumicis 
Linn,  just  because  Rumex  is  the  only  host  mentioned  in  the  origi- 
nal description.  In  the  history  of  aphidology,  probably  the  ma- 
jority of  species  have  been  described  from  a  single  host  many  years 
before  the  complete  life  history  was  understood  or  the  alternate 
hosts,  if  any,  were  known.  I  have  examined  some  of  Swain's 
material  and  find  that  it  agrees  with  similar  forms  which  I  have 
taken  in  Iowa  and  Pennsylvania,  and  with  material  from  Theo- 
bald in  England.  Therefore,  I  feel  that  we  are  not  justified  in 
making  the  change  proposed  by  Swain,  and  since  his  specific  name, 
euonomi,  varies  in  spelling  from  the  original  euonymi,  it  must  be 
considered  as  a  synonym  of  Aphis  rumicis  Linn. 

Several  other  names  have  been  incorrectly  listed  by  various 
authors  as  synonyms  of  A.  rumicis.  Schrank's  Aphis  gallii  Scabri 
(77)  I  consider  to  be  distinct  from  rumicis  since  his  description  of 
the  wingless  viviparous  female  from  bristly  Galium  calls  for  an 
aphid  with  "cornicles  and  cauda  short  appearing  as  scarcely  more 
than  elevated  spots.' ' 

Aphis  dahlice  Mosley  has  been  incorrectly  cited  as  a  synonym 
since  Mosley  (57)  described  an  amber-colored  aphid  with  legs, 
tubercles  (cornicles)  and  antennae  of  the  same  color  as  the  body. 

TECHNICAL  DESCRIPTIONS 
Egg:   (Plate  VIII,  A)   Elongate,  cylindrical,  slightly  flattened 
along  one  side,  bluntly  rounded  at  the  ends.     Olive-green  when 
first  deposited,  soon  turning  to  shiny  black.    Average  length  0.5 
mm. 

Stem  Mother:  (Plate  V,  I).  Velvet  black  tinged  with  olive. 
Body  oval,  broadly  rounded  behind.  Head  without  ocelli,  with  a 
few  scattering  hairs.  Eyes  black,  with  prominent  accessory  tuber- 
cles. Antennae  with  five  segments.  Prothorax  distinct  with  pair 
of  lateral  tubercles.  Mesothorax  and  metathorax  merged  in  out- 
line with  the  abdomen  which  is  arched  and  swollen.  Lateral 
tubercles  on  first  and  seventh  abdominal  segments  and  sometimes 
on  intervening  segments.     Cornicles  black,  tubular,  imbricated, 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

flanged  at  the  mouth.  Cauda  black,  distinctly  conical,  not  tapering 
as  in  apterous  viviparae,  furnished  with  several  curved  hairs  on  the 
margin.  Legs  shorter  and  stouter  than  in  apterous  viviparae  but 
similarly  colored.  Described  from  specimens  taken  on  Viburnum 
opulus  in  April  and  transferred  to  Rumex  crispus  for  generation 
series.  Measurements:  Length  of  body,  vertex  to  tip  of  cauda, 
1.896  to  2.292  mm. ;  Antenna,  I,  0.068  mm. ;  II,  0.051  mm. ;  III, 
.310  to  0.379  mm.;  IV,  0.137  to  0.172  mm.;  V  base,  0.103  mm.; 
V  unguis,  0.103  to  0.137  mm. ;  Cornicle,  0.155  to  0.206  mm. ;  Cauda, 
0.172  mm. ;  Hind  tarsus,  0.103  to  0.120  mm. 

First  Instar:  (Plate  IV,  G).  (Approximately  7  hours  old). 
Head  dark  purplish  green  with  slight  longitudinal  median  carina 
and  narrow  lateral  light-green  bands  bordering  the  eyes,  about 
four  hairs  on  vertex;  Eyes  dark  red  each  with  lateral  tubercle  of 
five  or  six  facets.  Antennae  pale,  faintly  tinged  with  green,  four- 
segmented,  the  distal  end  of  III  and  all  of  IV  dusky.  Prothorax 
olive-black  with  a  lateral  tubercle  on  each  side.  Mesothorax, 
metathorax,  and  abdomen  olive-green  with  a  purplish  tinge,  en- 
tirely covered  with  faint,  whitish  bloom.  Abdomen  with  a  distinct 
submarginal  groove  on  each  side  extending  back  to  the  cornicles  in 
which  are  distinct  pits,  segmentally  arranged.  Sides  of  each  ab- 
dominal segment  bearing  a  small  hair.  First  and  seventh  segments 
with  a  small  lateral  tubercle  on  each  side.  Lateral  tubercles  often 
present  on  intervening  segments.  Cornicles  dusky-black,  short, 
tubular.  Cauda  black,  short,  triangular,  with  fringe  of  about  five 
hairs  on  each  side.  Legs  stout,  clumsy,  whitish,  faintly  tinged  with 
green,  the  distal  ends  of  femora  and  tibiae  and  all  of  tarsi  blackish. 
Femora  sparsely  hairy,  tibiae  distinctly  hairy.  Measurements  from 
specimens  freshly  mounted  in  balsam:  Body  length,  0.756  mm., 
width,  0.369  mm. ;  Cornicles,  length,  0.047  mm.,  width,  0.035  mm. ; 
Antennae,  I,  0.044  mm. ;  II,  0.035  mm.,  Ill,  0.140  mm.,  IV  base, 
0.061  mm.  VI  unguis,  0.140  mm. 

Second  Instar:  (60  to  70  hours  old).  Similar  to  first  instar,  but 
darker  with  five-segmented  antennae,  longer  cornicles,  and  lateral 
tubercles  on  abdomen  more  distinct.  Measurements  from  specimens 
freshly  mounted  in  balsam :  Body  length,  0.739  mm.,  width,  0.404 
mm. ;  Cornicles,  length,  0.052  mm.,  width,  0.035  mm. ;  Antennae,  I, 
0.052  mm.,  II,  0.035  mm.,  Ill,  0.088  mm.,  IV,  0.070  mm.,  V  base, 
0.052  mm.,  V  unguis,  0.158  mm. 

Third  Instar:  (170-173  hours  old).  Similar  to  first  instar  with 
five-segmented  antennae.     Measurements  from  specimens  freshly 


APHIS  RUMICIS  15 

mounted  in  balsam:  Body  length,  G.950  mm.,  width,  0.528  mm.; 
Cornicles,  length,  0.073  mm.,  width,  0.038  mm. ;  Antennae,  I,  0.051 
mm.,  II,  0.044  mm.,  Ill,  0.140  mm.,  IV,  0.082  mm.,  V  base,  0.070 
mm.,  V  unguis,  0.170  mm. 

Fourth  Instar,  Apterous  Form:  (208-216  hours  old).  Similar 
to  first  instar  with  six-segmented  antennae.  Measurements  from 
specimens  freshly  mounted  in  balsam:  Body  length,  1.443  mm., 
width,  0.862  mm. ;  Cornicles,  length,  0.114  mm.,  width,  0.070  mm. ; 
Antennae  I,  0.070  mm.,  II,  0.056  mm.,  Ill,  0.158  mm.,  IV,  0.132 
mm.,  V,  0.132  mm.,  VI  base,  0.088  mm.,  VI  unguis,  0.246  mm. 

Fourth  Instar,  Pupa:  (Plate  IV,  F) :  General  shape  elongate- 
oval.  Head  and  prothorax  black  with  greenish-brown  hue,  slightly 
powdered.  Pair  of  lateral  tubercles  on  prothorax.  Prominent 
lobes  of  mesothorax  and  the  entire  metathorax  grayish-green. 
Abdomen  black  shaded  with  olive,  with  prominent  white  pulveru- 
lent patches  as  follows:  a  pair  of  round  areas  on  the  first  segment, 
a  broad  band,  often  broken  into  paired  spots,  on  either  side  of  a 
median  line  on  each  of  the  next  three  segments,  pairs  of  spots  close 
together  on  the  sixth  and  seventh  segments  and  faintly  showing 
on  the  eighth  segment.  These  white  areas  are  absent  from  fifth 
segment.  Lateral  tubercles  present  on  the  first  and  seventh  ab- 
dominal segments.  Antennae,  wing-pads,  cornicles,  and  cauda  black. 
Legs  colored  as  in  winged  viviparous  female.  Measurements : 
Length  of  body,  2.103  mm.;  Antennae,  I,  0.046  mm.;  II,  0.046  mm., 
Ill,  0.241  mm. ;  IV,  0.172  mm. ;  V,  0.163  mm. ;  VI  base,  0.094  mm. ; 
VI  unguis,  0.258  mm. ;  Cornicles,  0.181  mm. ;  Cauda,  0.120  mm. ; 
Hind  tarsus,  0.137  mm.  Described  from  specimens  on  Cheno- 
podium  album  and  Rumex  crispus,  October  1923.  The  pupae  of 
the  males  are  comparatively  smaller  in  size  but  resemble  in  color 
the  pupae  of  the  winged  viviparae  as  given  above. 

Winged  Viviparous  Female,  (Plate  II,  F) :  Morphological  char- 
acters:— Antennae,  measurements  given  in  Table  II.;  Segments  III 
to  VI  inclusive  imbricated,  armed  with  scattering  hairs,  which  are 
about  equal  in  length  to  width  of  each  segment  on  which  they  are 
borne;  III  bearing  10  to  22  round  sensoria  unevenly  distributed  over 
the  segment,  the  distal  4  or  5  arranged  in'  a  row,  IV  with  0  to  7 
sensoria,  V  with  the  usual  prominent  sensorium  near  the  distal  end 
and  sometimes  bearing  an  additional  proximal  one,  base  of  VI  with 
the  usual  compound  sensorium.  The  numbers  of  sensoria  vary  on 
the  corresponding  segments  of  the  two  antennae  of  the  same  indi- 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

vidual.  There  is  also  a  consistent  variation  in  the  number  of 
antennal  sensoria  of  the  spring  and  summer  migrants  and  of  the 
fall  migrants  or  sexuparae  alatae,  III  of  the  fall  migrant  usually 
bearing  about  4  more  secondary  sensoria  than  III  of  the  spring  or 
summer  alatae  and  IV  of  the  spring  forms  usually  without  sensoria 
while  IV  of  the  fall  form  may  have  as  many  as  7  or  8,  and  V  of  the 
fall  form  may  also  bear  1  or  2  in  addition  to  the  usual  primary 
sensorium.  Eyes  large,  with  prominent  lateral  tubercle.  A  single 
ocellus  contiguous  to  inner  margin  of  each  eye  a  little  distance  be- 
hind base  of  antenna,  a  third  ocellus  at  center  of  vertex,  slightly 
protruding.  Extending  back  from  the  median  ocellus  is  a  slight 
carina.  Prothorax  distinct,  bearing  a  pair  of  prominent  lateral 
tubercles.  Praeseutum,  scutellar  lobes,  and  scutellum  distinct. 
Abdomen  ovate,  suddenly  tapering  behind,  lateral  tubercles  always 
present  on  segments  1  and  7  and  sometimes  on  the  other  segments. 
Cornicles  imbricate,  tubular,  tapering  slightly,  with  flange  at  the 
mouth,  length  0.224  to  0.310  mm.,  slightly  shorter  in  fall  migrants. 
Anal  plate  rounded,  beset  with  numerous  hairs  and  short  spines. 
Cauda  cylindrical,  with  bluntly  pointed  tip,  numerous  short  spines 
and  4  to  5  long  curved  hairs  on  each  side,  length  0.137  to  0.206 
mm.,  shorter  in  fall  migrant.  Legs  slender,  with  numerous  short 
hairs,  length  of  hind  tarsus  0.123  to  0.146  mm.  Length  of  body, 
vertex  to  tip  of  cauda,  1.534  to  2.068  mm.  The  fall  migrants  are 
slightly  longer,  as  will  be  seen  in  accompanying  table. 

Color  characters: — General  color  to  unaided  eye  jet  black  with 
legs  dirty  yellow.  Under  the  binocular,  head  and  thorax  shining 
black;  eyes  brownish-black,  ocelli  lighter;  antennae  dark  brown  to 
black  with  lighter  area  at  base  of  III ;  labium  yellow  with  black 
tip;  legs  dusky  yellow  with  middle  and  hind  femora,  distal  one- 
fourth  of  tibiae  and  tarsi  black.  Wings  transparent,  veins  brownish 
with  stigma  smoky.  Abdomen  varying  from  deep  olive-green  to 
blackish-brown  with  black  dorsal  markings  which  become  distinct 
in  balsam  mounts  as  follows:  median  black  bands  on  each  abdom- 
inal segment,  those  on  the  first  six  segments  separate  and  distinct, 
with  those  on  the  seventh,  eighth  and  ninth  confluent.  Black 
patches  on  the  lateral  edges  of  each  segment  separated  more  or 
less  from  the  median  bands,  those  on  the  sixth  segment  more  ex- 
tensive than  the  others  forming  distinct  black  areas  behind  the 
base  of  each  cornicle.  The  extent  of  these  black  markings  on  the 
abdomen  is  subject  to  considerable  variation  among  different  in- 


APHIS  RUMICIS 


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18  IOWA  STUDIES  IN  NATURAL  HISTORY 

dividuals  of  the  same  generation  on  the  same  host  plant,  some 
specimens  having  only  disconnected  black  areas  in  place  of  median 
dorsal  bands.  Cornicles  black;  cauda  green  at  base,  distal  half 
black.  General  body  color  of  fall  migrants  as  noted  from  un- 
mounted material  varied  with  the  host.  Specimens  from  Euony- 
mus,  Philadelphus,  and  Hydrangea  were  blackish-brown  while  those 
taken  on  Chenopodium  and  Rumex  at  the  same  date  were  of  a  deep 
olive  cast.  Described  from  specimens  taken  on  Rumex  crispus  and 
Euonymus  atropurpureus  at  Bustleton,  Pa.,  in  May.  Measurements 
from  balsam  mounts. 

Apterous  Viviparous  Female,  (Plate  III,  B) :  Morphological 
characters: — Antenna*  shorter  than  body;  segments  V  and  VI 
distinctly  imbricated,  III  and  IV  faintly  so ;  a  single  primary  distal 
sensorium  on  V,  the  usual  compound  sensorium  at  base  of  VI 
unguis.  Eyes  large  with  ocular  tubercle  at  the  outer  posterior 
angle.  Prothorax  with  a  pair  of  distinct  lateral  tubercles,  other 
two  thoracic  segments  more  or  less  merged  in  outline  with  the 
abdomen.  Abdomen  ovate,  swollen,  often  with  segmentation  ob- 
scure. Lateral  tubercles  present  on  the  first  and  seventh  abdominal 
segments,  sometimes  present  on  intervening  segments  but  not  as 
distinct,  a  submarginal  row  of  pits  on  each  side  of  abdomen  ar- 
ranged segmentally  in  front  of  the  cornicles.  Cornicles  imbricated, 
cylindrical,  tapering  slightly  toward  the  mouth  which  is  flanged, 
length  0.224  to  0.396  mm.  Anal  plate  hemispherical,  furnished 
with  hairs  and  short  spines  as  is  the  genital  plate.  Cauda  cylin- 
drical, tapering  to  a  blunt  point,  four  or  five  curved  hairs  on  each 
margin,  covered  with  small  spines,  length  0.172  to  0.275  mm.  Legs 
slender,  sparsely  hairy,  length  of  hind  tarsus  0.114  to  0.137  mm. 
Length  of  body,  vertex  to  tip  cauda,  1.758  to  2.465  mm.  In  the 
fall,  the  apterous  forms  (sexuparae)  are  relatively  larger  than  the 
summer  apterae  but  the  cornicles  and  cauda  are  shorter. 
Color  characters: — General  color  to  the  unaided  eye  dull  black, 
sometimes  with  white  pulverulent  patches  on  the  back.  Very  often, 
in  mid-summer,  individuals  have  a  distinct  olive  green  cast  to  the 
abdomen,  especially  when  reared  in  shaded  situations.  In  the  fall, 
individuals  of  a  shiny  bronze  color  are  to  be  found  in  colonies  on 
Rumex  crispus  and  Arctium  lappa.  Many  of  these  forms  when 
examined  under  the  microscope  are  found  to  be  intermediates. 
Specimens  of  the  summer  forms  on  balsam  mounts  usually  show  a 
row  of  small  black  submarginal  spots  marking  the  location  of  the 


APHIS  RUMICIS  19 

pits  on  either  side  of  the  body  and  a  black  streak  at  the  base  of  the 
cauda.  Antennae  dirty  yellow  with  I,  II,  distal  end  of  V,  and  all 
of  VI  blackish.  Eyes  brownish-black.  Legs  dirty  yellow  with 
distal  two-thirds  of  middle  and  hind  femora,  distal  one-fourth  of 
tibiae,  and  tarsi  black.  Individuals  which  had  three  to  five  pairs 
of  pulverulent  patches  on  the  abdomen  were  reared  and  collected 
in  the  fall.  Described  from  specimens  taken  on  Rumex  crispus  in 
June  and  Rumex  crispus  and  Arctium  lappa  in  October,  1923,  at 
Bustleton,  Pa. 

TABLE  III 
COMPARATIVE  MEASUREMENTS  OF  APTEROUS  FEMALE 


Spring  Forms 

Length 
Body 
mm. 

III 

mm. 

IV 

mm. 

V 

mm. 

VI 

base 
mm. 

VI 

unguis 
mm. 

Corn, 
mm. 

'Rumex,  June 

11                 11 

1.89 
1.75 

0.370 
.396 

0.284 
.293 

0.258 
.241 

0.137 
.120 

0.396 
.310 

0.310 
.344 

Chenopodium,  June 

ii               ii 

2.46 

2.06 

.448 
.413 

.249 
.275 

.224 
.241 

.129 
.120 

.327 
.379 

.344 
.396 

Fall  Forms 

llumex,  Nov. 

ii         ii 

ii         ii 

2.37 
2.56 
2.42 

.387 
.316 
.316 

.228 
.202 
.246 

.211 
.184 
.220 

.105 
.105 
.114 

.299 
.281 
.325 

.228 
.220 
.255 

Chenopodium,  Nov. 

ii              ii 

ii              ii 

2.46 

2.28 
2.62 

.316 
.352 
.348 

.228 
.228 
.228 

.211 

.228 
.193 

.114 
.114 
.114 

.325 
.255 
.272 

.264 
.211 

.228 

Oviparous  Female,  (Plate  V,  B) :  Morphological  characters:— 
Antennae:  I,  0.044  to  0.061  mm.;  II,  0.035  to  0.047  mm.;  Ill, 
0.184  to  0.220  mm. ;  IV,  0.096  to  0.158  mm. ;  V,  0.123  to  0.158  mm. ; 
VI  base,  0.096  to  0.105  mm.;  VI  unguis,  0.176  to  0.237  mm.;  Seg- 
ments V  and  VI  distinctly  imbricated,  IV  faintly  so.  A  very  few 
hairs  along  the  entire  length  of  the  antennae,  scarcely  as  long  as 
width  of  respective  segments,  a  single  circular  sensorium  at  distal 
end  of  V  and  the  usual  compound  sensorium  at  the  base  of  VI 
unguis.  Eyes  distinct  with  the  usual  lateral  accessory  eye  on  each. 
Prothorax  distinct  with  a  pair  of  distinct  lateral  tubercles.  Other 
thoracic  segments  somewhat  indistinct  and  merged  in  outline  with 
the  abdomen.  Abdomen  ovate,  more  tapering  caudad  than  the 
apterous  viviparous  female,  a  pair  of  lateral  tubercles  present  on 
first  and  third  abdominal  segments,  smaller  tubercles  sometimes 
found    on    other    segments.      Cornicles    cylindrical,    imbricated, 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

flanged  at  the  mouth,  length  0.105  to  0.158  mm.  Cauda  conical  with 
bluntly  rounded  tip,  armed  with  numerous  papillae  and  several  long 
curved  hairs,  length  0.096  to  0.123  mm.  Anal  plate  hemispherical, 
papillate,  with  several  distinct  hairs.  Genital  plates  papillate,  two 
in  number.  Legs  hairy,  the  hind  tibiae  flattened  and  bearing  num- 
erous small  round  sensoria.  Length  of  hind  tarsus  0.105  to  0.123 
mm.    Length  of  body,  vertex  to  tip  of  cauda,  1.408  to  1.988  mm. 

Color  Characters: — General  color  to  unaided  eye  dull  black, 
suffused  with  olive  green  or  reddish-brown,  depending  upon  the 
host  upon  which  they  are  feeding.  Those  from  Euonymus  and 
Philadelphus  had  the  reddish  cast  while  those  on  Viburnum, 
Madura  pomifera,  Chenopodium  album,  and  Rumex  crispus  had 
the  olive  green  cast.  Antennae  blackish  with  the  exception  of 
segments  III  and  IV  which  are  dirty  yellow  in  color.  Cornicles 
and  distal  half  of  cauda  black.  Anal  and  genital  plates  black. 
First  and  second  pair  of  legs  yellowish  with  tips  of  tibiae  and  tarsi 
black.  Hind  pair  of  legs  black.  Described  from  specimens  taken 
on  Euonymus  alatus  at  Bustleton,  Pa.,  in  November.  Measure- 
ments from  balsam  mounts. 

Winged  Male,  (Plate  II,  A):  Morphological  Characters: — 
Antenna ;  Segments  III  to  VI  inclusive  are  imbricated,  armed  with 
scattering  hairs  which  are  more  prominent  than  those  on  the  alate 
female;  III  bears  24  to  41  prominent  sensoria,  unevenly  distri- 
buted, IV  with  15  to  25  sensoria,  V  with  7  to  16  sensoria  in  addi- 
tion to  the  usual  prominent  sub-apical  sensorium,  base  of  VI  with 
the  usual  compound  sensorium  at  the  base  of  the  unguis,  the  num- 
bers of  sensoria  on  segments  III,  IV,  and  V  may  vary  considerably, 
as  shown  in  Table  IV.  Eyes  large,  each  with  prominent  lateral 
tubercle  of  several  facets.  A  single  ocellus  on  either  side  of  head, 
contiguous  to  inner  margin  of  eye  and  somewhat  removed  from 
base  of  antennae,  a  third  prominent  ocellus,  somewhat  protruding 
at  center  of  vertex.  Prothorax  distinct,  slightly  narrower  than 
width  of  head,  bearing  a  pair  of  prominent  lateral  tubercles. 
Praescutum,  the  two  scutellar  lobes,  and  the  scutellum  prominent 
and  distinct.  Abdomen  ovate,  relatively  shorter  antero-posteriorly 
than  in  alate  female,  lateral  tubercles  present  on  1st,  7th  and  some- 
times other  abdominal  segments.  Cornicles  distinctly  imbricated, 
tubular,  with  distinct  flange  at  mouth,  length  0.088  to  0.149  mm. 
Anal  plate  rounded,  with  numerous  fine  hairs.  Cauda  cylindrical, 
tapering  distally  to  a  blunt  point,  with  6  to  8  curved  hairs,  length 


APHIS  RUMICIS  21 

0.086  to  0.140  mm.  Legs  slender,  hairy.  Length  of  hind  tarsus 
0.103  to  0.137  mm.  Length  of  body,  vertex  to  tip  of  cauda,  1.137 
to  1.900  mm. 

Color  characters: — General  color  to  the  unaided  eye  is  shining 
black  with  legs  lighter.  Under  the  binocular  the  head  and  thoracic 
segments  are  seen  to  be  shining  black,  with  eyes  brownish-black. 
Labium  dusky  yellow  with  black  tip.  Antennae  deep  brown.  Legs 
dusky  yellow  with  femora  of  middle  and  hind  legs,  distal  tips  of 
front  femora,  one-fourth  of  all  tibiae,  and  all  tarsi  black.  Wings 
transparent  with  blackish  veins  and  smoky  stigma.  Abdomen 
almost  black  with  an  olive-green  tinge  through  which  the  jet:black 
markings  are  discernible.  Black  bands,  irregular  in  outline  and 
extent,  on  each  of  the  first  five  segments,  sometimes  reaching  the 
two  lateral  margins  but  often  broken  to  form  a  central  band  and 
lateral  spots.  Behind  the  cornicles,  the  entire  dorsum  of  each 
segment  is  black.  Cornicles  and  cauda  black.  Described  from 
specimens  taken  on  Chenopodium  album  and  Euonymus  alatus,  at 
Bustleton,  Pa.    Measurements  from  balsam  mounts. 

TABLE  IV— COMPARATIVE   MEASUREMENTS  OF  MALES 


Ill 

IV 

V 

VI 

VI 

Corn. 

Sensoria 

mm. 

mm. 

mm. 

base 

unguis 

mm. 

III 

IV 

V 

Chenopodium 

0.352 

0.193 

0.176 

0.105 

0.290 

0.088 

28 

16 

13 

>i 

.334 

.228 

.190 

.102 

.334 

.105 

31 

16 

12 

>y 

.334 

.211 

.176 

.096 

.272 

.088 

34 

17 

16 

99 

.334 

.193 

.158 

.096 

.264 

.088 

39 

22 

12 

99 

.334 

.246 

.220 

.114 

.343 

.132 

30 

18 

14 

Eumex 

.352 

.311 

.272 

.132 

.369 

.149 

26 

17 

7 

>  j 

.369 

.281 

.246 

.123 

.369 

.140 

30 

17 

7 

Madura 

.334 

.299 

.237 

.123 

.334 

.140 

34 

18 

10 

99 

.325 

.246 

.211 

.114 

.334 

.105 

36 

20 

10 

Calycanthus 

.396 

.313 

.241 

.137 

.310 

.103 

37 

25 

11 

99 

.343 

.284 

.189 

.094 

.241 

.103 

35 

21 

8 

?> 

.362 

.262 

.206 

.103 

.336 

.120 

31 

25 

6 

Euonymus 

.413 

.310 

.258 

.120 

.336 

.137 

31 

22 

12 

>> 

.343 

.241 

.206 

.103 

.275 

.137 

25 

17 

11 

>  > 

.396 

.275 

.241 

.120 

.379 

.103 

32 

17 

9 

99 

.379 

.275 

.215 

.103 

.120 

38 

19 

14 

?> 

.413 

.275 

.241 

.103 

.343 

.137 

41 

21 

12 

Intermediates  in  the  Aphidse  are  of  interest  because  of  their  pos- 
sible phylogenetic  significance.  Apterous  forms  with  traces  of 
alate  characters  seem  to  indicate  that  the  wingless  forms  evolved 
from  the  winged  individuals.  Baker  and  Turner  (3)  stated  that 
they  had  noted  an  intermediate  in  Aphis  rumicis,  but  they  gave 


22  IOWA  STUDIES  IN  NATURAL  HISTORY 

no  description  of  the  form.  In  my  studies,  intermediates  of  several 
forms  were  collected  or  reared. 

Intermediate  Male,  (Plate  III,  A) :  Color  and  appearance  very 
nearly  that  of  the  alate  male.  Measurements  of  one  individual  as 
follows:  Antennae,  III,  0.413  mm.  bearing  5  secondary  sensoria 
of  normal  size  and  many  microscopic  sensoria,  IV,  0.293  mm. 
bearing  about  10  tiny  sensoria,  V,  0.258  mm.  bearing  about  10  tiny 
sensoria  and  the  usual  primary  distal  sensorium,  VI  base,  0.137 
mm.,  unguis  0.344  mm.;  Cornicles  0.155  mm.,  Cauda,  0.155  mm., 
Hind  tarsus,  0.103  mm.  Ocelli  present  on  head  as  in  alate  form. 
Mesothorax  chitinized  but  with  only  a  slight  indication  of  lobes. 
The  wings  are  represented  on  both  thoracic  segments  by  small 
buds  which  are  visible  by  transmitted  light.  A  second  specimen 
has  the  normal  number  of  sensoria,  i.  e.  Ill,  32 ;  IV,  19 ;  V,  12 ;  and 
indication  of  thoracic  lobes,  and  wings  represented  by  four  small 
pads. 

Described  from  three  specimens  taken  with  winged  males  on 
Arctium  lappa,  October  11,  1922,  Bustleton,  Pa. 

Intermediate  Viviparous  Female,  (Plate  V,  G).  General  size  and 
form  of  body  approaching  that  of  the  apterous  sexupara.  Color 
of  antenna?,  cornicles,  cauda,  and  legs  similar  to  apterous  form. 
Abdomen  with  distinct  black  bands  segmentally  arranged  as  in 
alate  form,  black  patches  present  at  the  base  of  the  cornicles,  but 
absent  from  the  abdominal  margin.  Rows  of  small  black  spots 
marking  the  pits  same  as  in  apterous  form.  Thoracic  lobes  dis- 
tinct, praeseutum  and  scutellum  present,  but  reduced  in  size. 
Wings  represented  by  four  flaps  projecting  from  the  sides.  A 
second  specimen  on  the  same  slide  has  the  black  markings  on  the 
abdomen  similar  to  those  described  above  but  not  as  distinct. 
Alate  characters  of  the  thorax  exhibited  in  a  chitinized  surface 
and  a  faint  groove  showing  a  division  into  the  two  lobes.  Wings 
indicated  only  by  four  small  buds. 

Described  from  two  specimens  taken  on  Rumex  obtusifolius, 
November  3,  1923,  at  Bustleton,  Pa.  The  following  note  was  m#de 
at  time  of  collection,  "  shiny,  viviparous  female/ '  A  third  speci- 
men collected  on  Chenopodium  album,  November  1,  1923,  had 
markings  similar  to  the  first  specimen  described  above,  but  had  5 
secondary  sensoria  on  segment  III  of  antennae,  and  5  sensoria  on 
IV,  unguis  of  VI  was  aborted. 

Intermediate  Oviparous  Female,  (Plate  V,  H.)  :  General  form 
and   appearance   of   the   apterous   viviparous   female.     Antennae 


APHIS  RUMICIS  23 

shorter  than  the  viviparous  form  but  longer  than  the  true  oviparous 
form.  Segment  III,  0.275  mm.;  IV,  0.172  mm.;  V,  0.155  mm.; 
VI,  base,  0.103  mm. ;  VI  unguis,  0.224  mm.  All  of  IV,  V,  and  VI 
blackish,  distinctly  imbricated,  III  faintly  imbricated.  The  hind 
tibiae  are  slender  as  in  the  viviparous  female,  but  about  one-fifth 
shorter.  Three  full  sized  ova  are  clearly  seen  within  the  abdomen 
of  one  specimen. 

Described  from  three  specimens  reared  in  generation  series, 
October,  1922,  Bustleton,  Pa.  Two  of  these  females  mated  with 
males  taken  from  Arctium  lappa  in  the  field  and  the  third  with  a 
male  reared  on  Rumex  crispus.  Ova  were  deposited  by  these  fe- 
males on  Rumex  obtusifolius. 

LIFE  HISTORY  STUDIES 

METHODS  OF  STUDY 

The  rearing  experiments  were  carried  on  at  the  Pennsylvania 
State  College  Field  Laboratory,  Bustleton,  Pa.,  during  the  sum- 
mers of  1920-21-22  and  23  in  the  insectary  and  in  the  field  cages. 
A  series  was  also  reared  from  September  1921  to  June  1922  in  the 
greenhouse  of  the  Department  of  Botany,  State  University  of  Iowa, 
Iowa  City,  Iowa.  The  insectary  consisted  of  a  shelter  roof  with 
open  sides.  Protection  from  beating  rains  was  provided  by  using 
side  curtains  of  thin  muslin  (Plate  IX,  A).  Some  of  the  plants 
were  grown  in  a  dirt  bench  and  some  were  planted  in  seven  inch 
pots.  The  soil  used  was  a  fairly  rich  compost  of  sand,  clay  soil, 
and  manure.  Growing  potted  plants  were  used  for  all  generation 
and  transfer  experiments,  with  the  exception  of  the  generations 
on  woody  plants.  Cuttings  placed  in  water  or  damp  sand  were 
used  for  the  experiments  on  Euonymus,  Viburnum,  Hydrangea 
and  Madura. 

Two  types  of  cages  were  used  in  the  rearing  work.  One  type 
consisted  of  ordinary  glass  lantern  globes  over  the  top  of  which 
thin  covers  of  cheese  cloth  were  fastened.  The  second  type  or 
field  cage,  the  same  as  used  by  Smith  (81),  was  made  by  stretching 
muslin  over  wooden  frames  of  inch  material.  The  corner  strips 
extended  six  inches  below  the  bottom  level  of  the  cage  and,  when 
sunk  into  the  ground,  served  as  anchorages  (Plate  IX,  B).  The 
entrance  was  provided  by  running  a  width  of  cloth  around  one 
side  of  the  frame  which  had  been  left  uncovered.  When  this  was 
sewed  together  at  the  two  loose  ends,  it  formed  a  sleeve  enveloping 


24  IOWA  STUDIES  IN  NATUEAL  HISTORY 

the  body  while  examinations  were  being  made  and  prevented 
escape  of  winged  forms  or  entrance  of  parasites.  This  cloth  was 
gathered  to  the  center  and  tied  when  the  cage  was  closed.  The 
cages  were  of  two  sizes,  14"xl4"x30"  and  30"x30"x30".  Maximum 
and  minimum  temperatures  were  recorded  throughout  each  season. 

In  the  generation  experiments  the  usual  method  was  followed. 
The  viviparous  female  was  removed  by  means  of  a  small  brush  at 
the  end  of  her  first  day  of  reproduction.  She  was  then  placed  on 
a  growing  plant  free  from  aphids,  and  data  on  the  number  of 
young,  etc.  were  thus  obtained  each  day  of  her  life.  As  Davis  has 
suggested,  the  method  of  leaving  several  new-born  young  instead  of 
a  single  individual  insures,  almost  to  a  certainty,  the  continuation 
of  the  line.  These  first-born  young  were  checked  at  maturity  in 
order  to  determine  the  presence  or  absence  of  winged  individuals. 
The  series  for  1923  outlined  in  detail  in  Tables  VI  and  VIII  are 
representative  of  the  generation  experiments  of  the  previous  three 
years. 

FOOD  PLANTS 

ApMs  rumicis  Linn,  is  an  exceptionally  polyphagous  aphid. 
The  majority  of  the  species  of  the  Aphidae  are  restricted  in  their 
feeding  habits  to  a  small  number  of  plants,  but  this  insect  has 
adapted  itself  to  a  wide  range  of  hosts.  Wilson  and  Vickery  (99) 
have  listed,  under  Aphis  rumicis  or  the  synonyms  included  in  their 
paper,  189  species  of  host  plants.  Patch  (66,  67,  68,  70,  71)  has 
cited,  in  the  various  parts  of  her  Pood  Plant  List,  17  additional 
hosts  and  in  the  Hemiptera  of  Connecticut  (10)  3  other  species. 
Swain  (84)  records  8  species  of  plants  not  included  in  the  above 
lists  and  I  have  collection  records  for  9  additional  hosts.  This 
brings  the  total  number  of  recorded  hosts  for  Aphis  rumicis  to  226. 
A  few  of  these  may  be  incorrect  citations  since  they  may  refer  to 
species  of  aphids  which  have  been  erroneously  placed  as  synonyms 
of  Aphis  rumicis.  Only  one  other  aphid  approaches  rumicis  in 
its  wide  range  of  accepted  hosts,  i.e.  Myzus  persicce  Sulz.,  for  which 
Wilson  and  Vickery  list  175  food  plants. 

My  additional  records  are  as  follows:  Primary  hosts: — Caly- 
canthus  fertilis,  Euonymus  alatus,  Hydrangea  paniculata,  Madura 
pomifera,  and  Chenopodium  album;  Secondary  hosts: — Aster  sp., 
Chenopodium  ambrosioides,  Galinsoga  parviflora,  Polygonum 
scandens  var.  dumetorum,  and  Stellaria  media.  Other  plants  upon 
which  I  have  collected  or  reared  this  aphid  are  given  in  the 


APHIS  RUMICIS  25 

Seasonal  History  Chart  (Table  XII).  The  large  number  of  hosts 
upon  which  this  insect  is  able  to  exist  accounts  in  part  for  its 
abundance  and  cosmopolitan  distribution.  The  ultimate  result  of 
this  polyphagous  habit  may  be  that  several  physiological  species 
may  arise  which,  in  time  will  exhibit  distinctive  morphological 
characters. 

TRANSFER  TESTS 
During  the  four  seasons  in  which  life  history  studies  on  Aphis 
rumicis  were  being  conducted,  considerable  attention  was  devoted 
to  transfers  of  aphids  from  one  host  plant  to  another  at  various 
seasons  of  the  year.  It  was  desirable  to  obtain  these  data  for  two 
reasons:  first,  to  establish  more  certainly  the  specific  identity  of 
forms  collected  from  different  host  plants  but  having  no  distinct 
morphological  differences  of  apparent  specific  value;  second,  to 
verify  the  summer  and  winter  host  plants  upon  which  this  species 
lives  in  localities  covered  by  these  studies.  The  data  were  obtained 
in  the  following  manner.  The  desired  host  plants  were  grown  in 
6  and  7  inch  pots  in  an  out-of-doors  insectary.  These  plants  were 
covered  with  lantern  globes,  the  tops  of  which  were  covered  with 
a  single  thickness  of  cheese  cloth.  Specimens  were  reared  from  ova 
or  were  collected  from  colonies  breeding  in  the  field  or  at  the 
insectary  on  the  host  of  a  different  species  than  that  to  be  tested. 
In  most  cases  several  aphids  were  transferred  to  the  potted  plant 
by  means  of  a  soft  brush  and  observations  made  from  time  to  time. 
Whenever  possible  winged  females  were  used  in  making  the  test 
and  no  experiment  was  considered  successful  until  progeny  of  the 
transferred  form  matured  and  produced  young.  These  tests  nec- 
essitated the  use  of  twenty-two  species  of  host  plants  grouped  in 
forty-three  different  combinations.  In  addition,  notes  were  taken 
in  the  field  on  transfers  effected  by  the  insects  themselves,  under 
conditions  which  were  very  reliable.  These  transfers  included 
combinations  in  addition  to  those  used  under  controlled  conditions. 
These  records  will  be  indicated  as  such  in  table  V  so  that,  unless 
specifically  stated,  the  experiments  as  tabulated  were  under  con- 
trolled conditions.  It  might  be  well  to  explain  here  that  such  ex- 
periments are  of  peculiar  value  in  working  out  authentic  hosts, 
since  aphids  are  particularly  selective  in  their  feeding  habits.  In- 
dividuals, when  placed  upon  plants  which  are  not  the  normal  food 
of  the  species,  will  crawl  from  the  plants  to  the  sides  or  top  of  the 
cage  and  remain  there  until  they  die  rather  than  feed  upon  this 
foreign  plant. 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

TABLE  V— TRANSFER  EXPERIMENTS,  APHIS  BUMICIS 


Transfers  to 
Chenopodium  album 


Beta  vulgaris 
Bumex  crispus 


Bumex  obtusifolius 


Phaseolus   ?p. 
Papaver  sp. 
Mirabilis  jalapa 
Arctium  lappa 


Bheum  rhaponticum 


Spinacia  oleracea 
Amaranthus  retroflexus 
Asparagus  sp. 
Stellaria  media 
Viburnum  opulus 
Euonymus  atropurpureus 
Madura  pomifera 
Oenothera  biennis 
Galinsoga  parvi flora 
Bosa   sp. 
Gladiolus  sp. 
Dahlia  sp. 
Pisum  sp. 
Capsella  bursapastoris 


From  Remarks 

Viburnum   opulus 

Viburnum   opulus 

Daucus  carota  unsuccessful 

Dahlia  sp. 

Gladiolus  sp. 

Spinacia  oleracea 

Bumex  crispus 

Arctium  lappa 

>>  >> 

Chenopodium  album 

Bheum  rhaponticum 

Bumex  crispus  (Davidson,  B.  sanguineus) 

Chenopodium  album 

Bheum  rhaponticum 

Bumex  crispus  (Davidson,  B.  sanguineus) 

Begonia  sp. 

Arctium  lappa 

Dahlia  sp. 

Gladiolus  sp. 

Chenopodium  album 

Daucus  carota 

Viburnum  opulus  (Osborn  and  Sirrine) 


Euonymus  atropurpureus 

Madura  pomifera 
Amaranthus  retroflexus 
Pisum  sp. 

Chenopodium  album 
Bumex  crispus 
Chenopodium  album 
Tropceolum  minus 
Viburnum  opulus 
Tropceolum  minus 
Chenopodium  album 
Bumex  crispus 
Viburnum  opulus 
Bumex  crispus 
Arctium  lappa 
Chenopodium  album 
Viburnum  opulus 
Pisum  sp. 
Bumex  crispus 
Chenopodium  album 
Chenopodium  album 
Chenopodium,  album 
Chenopodium  album 
Chenopodium  album 
Chenopodium  album 
Chenopodium  album 
Tropceolum  minus 
Tropceolum  minus 
Tropwolum  minus 
Chenopodium  album 


(Davidson,  B. 
sanguineus) 


(Ohlendorf) 
unsuccessful 


colony  weak 


Ova 

field 
field 

field 
field 
field 
field 


APHIS  RUMICIS  27 

Osborn  and  Sirrine  (65)  made  successful  transfers  of  this  aphid 
from  Euonymus  atropurpureus  to  Viburnum  opulus  and  from  this 
stock  on  Viburnum  to  shepherd's  purse,  curled  dock  and  beans. 
They  failed  to  establish  aphids  from  Viburnum  on  Euonymus.  It 
may  be  that  in  making  this  latter  test  they  were  using  Aphis 
viburniphila  Patch,  another  dark  form  on  Viburnum.  Theobald 
(88)  reported  that  he  had  made  transfers  of  Aphis  rumicis  from 
Euonymus  europceus  to  broad  beans  (Vicia  sp.).  Swain  (84) 
failed  to  secure  colonies  of  this  aphid  on  Hedera  helix  or  Rumex 
sp.  when  material  was  transferred  from  Vicia  sp.  Ohlendorf  (62) 
made  successful  transfers  from  Philadelphus,  Euonymus,  and 
Viburnum  opulus  to  Euonymus  europceus  and  Viburnum  opulus. 
The  same  worker  failed  to  make  successful  transfers  from  nastur- 
tium to  Euonymus  or  from  Rumex  obtusifolius  to  apple,  lima  bean, 
or  turnip.  He  did  succeed  in  securing  colonies  upon  nasturtium, 
navy  bean,  and  pea  from  stock  on  Rumex  obtusifolius. 

Davidson  (15-20),  who  has  done  the  most  work  with  Aphis 
rumicis  along  this  line,  recorded  successful  transfers  from  Euony- 
mus to  broad  bean,  horse  bean,  dwarf  French  bean,  peas,  poppies, 
Rumex  sp.  and  Euonymus.  He  also  secured  colonies  on  Euonymus 
from  stock  on  broad  bean.  From  material  which  he  transferred  to 
Rumex  from  Euonymus,  he  secured  colonies  by  re-transfer  on  broad 
bean,  horse  bean,  dwarf  French  bean,  peas,  poppies,  Rumex  sp., 
mangolds,  red  beets,  and  sugar  beets. 

The  combinations  which  I  used  in  making  my  tests  were  largely 
determined  by  the  common  hosts  upon  which  I  had  taken  colonies 
of  Aphis  rumicis  in  the  field.  For  this  reason  there!  is  a  distinct 
departure  from  the  combinations  used  by  Davidson  in  the  experi- 
ments which  he  followed  in  England.  Three  combinations  of  hosts 
which  are  similar  to  those  used  by  Davidson  are  indicated  in  the 
table.  However,  he  used  Euonymus  europceus  and  Rumex  san- 
guineus. In  one  unsuccessful  case  which  I  have  listed,  transfers 
were  made  successfully  to  another  known  host.  Thus  aphids  from 
stock  on  Daucus  carota,  when  transferred  to  Chenopodium  album, 
did  not  colonize  the  second  host,  but  did  colonize  Rumex  crispus. 
Since  repeated  transfers  were  successfully  made  between  Rumex 
crispus  and  Chenopodium  album,  the  failure  mentioned  did  not 
throw  out  Daucus  carota  as  a  host  plant  of  Aphis  rumicis. 

Since  the  aphids  collected  in  the  field  from  the  various  host  plants 
and  those  used  in  these  tests  do  not  differ  from  each  other  by 


28 


IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  VI     Aphis  rumicis— 1923— Bustleton,  Pa. 


Date 

Temp. 

First-born  Generation  Series 

Max. 

Min. 

1 

1-1 

1-2 

1-3 

2 

2-1 

2-2 

April  4 

70 

54 

b* 

5 

74 

56 

X 

6 

66 

42 

X 

7 

69 

36 

X 

8 

62 

40 

X 

9 

50 

28 

X 

10 

56 

30 

X 

11 

64 

35 

X 

12 

61 

38 

X 

13 

56 

42 

X 

M 

14 

42 

34 

X 

X 

15 

43 

32 

X 

X 

16 

58 

34 

3 

b 

X 

17 

55 

35 

3 

X 

X 

18 

53 

31 

X 

X 

19 

59 

32 

X 

X 

20 

82 

34 

X 

X 

21 

84 

47 

X 

X 

22 

72 

58 

X 

X 

23 

68 

53 

X 

X 

24 

60 

37 

X 

X 

25 

66 

44 

X 

3 

b 

26 

68 

56 

X 

X 

27 

73 

63 

3 

b 

X 

28 

75 

47 

2 

X 

X 

29 

64 

53 

X 

X 

30 

61 

44 

X 

X 

May  1 

66 

36 

X 

X 

2 

70 

39 

X 

X 

3 

71 

41 

X 

X 

4 

81 

41 

X 

X 

5 

78 

43 

X 

X 

6 

74 

49 

X 

X 

7 

77 

48 

X 

X 

8 

75 

48 

X 

5 

b 

9 

66 

40 

X 

X 

10 

56 

36 

3 

b 

X 

11 

67 

32 

6 

X 

X 

12 

76 

55 

5 

X 

X 

13 

72 

55 

4 

X 

X 

14 

73 

45 

e 

X 

X 

b — born         d — died         e — incomplete  record         x — dev.  period 

*  Stem  mother  from  eggs  on  Chenopodium  album,  all  generations  reared  on 

Rumex  crispus. 
§  Stem  mother  from  eggs  on  Viburnum  opulus,  generations  2  to  15  reared  on 

Rumex  crispus,  18  to  20  on  Chenopodium  album. 


APHIS  RUMICIS 


29 


TABLE  VI  (Coat.)     Aphis  rumicia — 1983— B  jstleton,  Pa. 


Temp. 

First-born  Generation  Series 

Date 

Max. 

Min. 

1-3 

1-4 

1-5 

1-6 

1-7 

2-2 

2-3 

2-4 

2-5 

2-6 

May  15 

16 

45 

X 

X 

16 

77 

58 

X 

X 

17 

77 

53 

X 

X 

18 

71 

48 

X 

X 

19 

75 

54 

X 

X 

20 

76 

49 

X 

X 

21 

73 

54 

X 

X 

22 

70 

56 

X 

X 

23 

72 

54 

X 

X 

24 

72 

56 

X 

5 

b 

*  25 

80 

56 

2 

b 

6 

X 

26 

83 

62 

8 

X 

2 

X 

27 

85 

60 

8 

X 

11 

X 

28 

80 

54 

5 

X 

4 

X 

29 

88 

56 

2 

X 

10 

X 

SO 

80 

57 

3 

X 

5 

X 

31 

75 

56 

3 

X 

5 

X 

June  1 

80 

49 

2 

X 

6 

X 

2 

93 

59 

4 

X 

9 

6 

b 

3 

89 

62 

5 

11 

b 

8 

11 

X 

4 

87 

61 

9 

10 

X 

5 

6 

X 

5 

87 

70 

4 

8 

X 

10 

7 

X 

6 

88 

75 

0 

8 

X 

3 

e 

X 

7 

81 

68 

d 

11 

X 

6 

X 

8 

78 

60 

2 

X 

2 

X 

9 

69 

55 

2 

X 

2 

X 

10 

78 

51 

6 

X 

2 

4 

b 

11 

76 

57 

8 

2 

b 

0 

7 

X 

12 

80 

54 

1 

1 

X 

0 

2 

X 

13 

70 

56 

3 

3 

X 

0 

2 

X 

14 

86 

60 

2 

2 

X 

0 

4 

X 

15 

82 

59 

7 

6 

X 

1 

5 

X 

16 

81 

59 

3 

0 

X 

0 

2 

X 

17 

88 

60 

4 

9 

X 

d 

3 

X 

18 

91 

54 

2 

8 

X 

3 

a 

b 

19 

90 

57 

1 

1 

X 

Id 

2 

X 

20 

100 

66 

2 

5 

1 

b 

6 

X 

21 

98 

80 

0 

4 

2 

X 

6 

X 

22 

92 

69 

0 

4 

3 

X 

0 

X 

23 

87 

60 

0 

4 

2 

X 

7 

X 

24 

99 

80 

d 

4 

4 

X 

e 

X 

30 


IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  VI  (Cont.)     Aphis  rumicis— 1923— Bustleton,  Pa. 


Temp. 

First-born  Generation  Series 

Last-born 
Gen.  Series 

Date 

Max. 

Min.| 

1-5 

1-6 

1-7 

1-8 

1-9 

1-10 

l-ll 

1-12 

2-6 

2-7 

2-8 

2-9 

2-10 

2-11 

l-8a 

l-8b 

June  25 

96 

67 

2 

4 

X 

X 

26 

91 

79 

4 

5 

X 

X 

27 

87 

67 

0 

d 

X 

X 

28 

87 

64 

2 

X 

4 

b 

29 

75 

59 

3 

2 

b 

3 

X 

30 

81 

59 

0 

3 

X 

2 

X 

July  1 

84 

49 

0 

3 

X 

2 

X 

2 

83 

54 

0 

3 

X 

3 

X 

3 

76 

56 

0 

2 

X 

1 

X 

4 

85 

61 

0 

4 

X 

0 

X 

5 

92 

60 

0 

2 

X 

3 

X 

6 

86 

68 

0 

2 

X 

1 

X 

7 

85 

59 

0 

6 

4 

b 

1 

2 

b 

8 

84 

55 

d 

1 

1 

X 

le 

3 

X 

9 

83 

59 

3 

2 

X 

3 

X 

10 

91 

66 

3 

3 

X 

5 

X 

11 

88 

70 

3 

11 

X 

6 

X 

12 

87 

70 

d 

8 

X 

4 

X 

13 

89 

65 

3 

X 

8 

X 

14 

86 

60 

4d 

2 

b 

5 

X 

b 

15 

82 

67 

5 

X 

5 

2 

b 

X 

16 

88 

67 

2 

X 

6 

3 

X 

X 

17 

87 

62 

5 

X 

2 

2 

X 

X 

18 

90 

63 

0 

X 

4 

2 

X 

X 

19 

85 

57 

0 

X 

3 

3 

X 

X 

20 

90 

55 

1 

X 

1 

2 

X 

1 

21 

97 

67 

1 

X 

2d 

4 

X 

10 

22 

91 

67 

0 

2 

b 

5 

X 

5 

23 

81 

58 

d 

7 

X 

5 

X 

6 

24 

77 

57 

2 

X 

2 

X 

2 

25 

83 

65 

2 

X 

3 

X 

3 

26 

82 

58 

4 

X 

2 

1 

b 

4 

27 

82 

55 

3 

X 

2 

2 

X 

3 

28 

80 

65 

4 

X 

3 

4 

X 

3 

b 

29 

89 

68 

4 

X 

1 

2 

X 

3 

X 

30 

81 

67 

d 

1 

b 

Id 

1 

X 

d 

X 

31 

67 

62 

1 

X 

1 

X 

X 

Aug.  1 

70 

60 

3 

X 

2 

X 

X 

2 

84 

62 

2 

X 

0 

X 

X 

3 

89 

68 

1 

X 

2 

X 

X 

4 

90 

70 

2d 

X 

1 

2 

b 

X 

5 

88 

72 

X 

6 

4 

X 

1  x 

APHIS  RUMICIS 


31 


TABLE  VI  (Cont.)     Aphis  rumicis— 1923— Bustleton,  Pa. 


Temp. 

First-bt  rn 

Last-born 

Generation  Series 

Gen.  Series 

Date 

Max. 

Min. 

1-12 

1-13 

1-14 

1-15 

1-16 

2-9 

2-10 

2-11 

2-12 

2-13 

2-14 

2-15 

l-8b 

l-8c 

l-8d 

l-8e 

Aug.  6 

99 

65 

X 

6 

5 

X 

5 

7 

89 

67 

1 

b 

3 

5 

X 

5 

8 

89 

72 

1 

X 

1 

3 

X 

1 

b 

9 

84 

76 

2 

d 

d 

2 

X 

d 

X 

10 

84 

69 

1 

b 

3 

X 

X 

11 

81 

75 

d 

X 

0 

X 

X 

12 

84 

70 

X 

2 

3 

b 

X 

13 

81 

68 

X 

d 

2 

X 

X 

14 

80 

62 

X 

2 

X 

X 

15 

88 

66 

X 

4 

X 

X 

16 

77 

57 

X 

4 

X 

1 

17 

71 

59 

X 

2 

X 

2 

b 

18 

83 

62 

X 

3 

X 

d 

X 

19 

83 

53 

2 

b 

0 

X 

X 

20 

81 

62 

4 

d 

d 

X 

X 

21 

86 

52 

1 

3 

b 

X 

22 

82 

53 

1 

b 

2 

X 

X 

23 

72 

56 

d 

X 

2 

X 

X 

24 

78 

53 

X 

0 

X 

X 

25 

81 

60 

X 

1 

X 

X 

26 

82 

62 

X 

2 

X 

X 

27 

81 

54 

X 

2 

X 

X 

28 

84 

64 

X 

e 

X 

X 

29 

81 

64 

X 

X 

2 

30 

85 

61 

X 

X 

Id 

b 

31 

84 

56 

2 

b 

4 

b 

X 

Sept.  1 

83 

59 

4 

X 

3 

X 

X 

2 

87 

67 

3 

X 

3 

X 

X 

3 

85 

61 

5 

X 

3 

X 

X 

4 

91 

68 

1 

X 

4 

X 

X 

5 

80 

64 

1 

X 

4 

X 

X 

6 

81 

61 

2 

X 

3 

X 

X 

7 

83 

62 

2 

X 

3 

X 

5 

8 

82 

66 

1 

X 

1 

X 

2 

9 

80 

57 

0 

X 

3 

X 

4 

10 

75 

62 

0 

2 

b 

3 

2 

b 

4 

11 

77 

62 

0 

3 

X 

1 

3 

X 

2 

12 

79 

57 

0 

2 

X 

2 

2 

X 

2 

13 

77 

58 

0 

2 

X 

3 

0 

X 

2 

14 

69 

58 

d 

2 

X 

0 

1 

X 

3 

15 

68 

42 

2 

X 

1 

2 

X 

3 

16 

70 

50 

3 

X 

d 

1 

X 

2 

IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  VI  (Cont.)     Aphis  rumieis— 1923— Bustleton,  Pa. 


First-born 

Last-born 

lemp. 

Generation  Series 

Gen.  Series 

Date 

Max 

Mid. 

1-15 

1-16 

1-17 

1-18 

1-19 

2-14 

2-15 

2-16 

2-17 

2-18 

l-8e 

l-8f 

Sept.  17 

72 

40 

2 

X 

0 

X 

1 

18 

74 

38 

0 

X 

0 

X 

g 

19 

82 

60 

2 

X 

2 

X 

2 

20 

80 

64 

6 

X 

4 

X 

6 

b 

21 

73 

67 

3 

X 

1 

4 

b 

d 

X 

22 

73 

66 

2 

2 

b 

g 

4 

X 

X 

23 

80 

m 

3 

3 

X 

2 

4 

X 

X 

24 

83 

65 

5 

o 

X 

2 

5 

X 

X 

25 

85 

60 

4 

1 

X 

0 

1 

X 

X 

26 

79 

58 

1 

0 

X 

1 

d 

X 

X 

27 

78 

61 

3 

2 

X 

4 

X 

X 

28 

80 

58 

1 

1 

X 

3 

X 

X 

29 

81 

58 

4 

1 

X 

0 

1 

b 

4 

30 

68 

50 

0 

3 

X 

1 

2 

X 

2 

Oct.   1 

67 

44 

d 

0 

X 

d 

1 

X 

0 

2 

72 

52 

d 

X 

2 

X 

2 

3 

68 

45 

X 

1 

X 

1 

4 

73 

44 

X 

2 

X 

2 

5 

62 

37 

2 

b 

3 

X 

2 

0 

62 

40 

1 

X 

0 

X 

3 

7 

63 

32 

0 

X 

0 

X 

0 

8 

64 

34 

0 

X 

1 

X 

0 

9 

68 

40 

0 

X 

0 

X 

3 

10 

70 

38 

0 

X 

1 

X 

2 

11 

67 

45 

0 

X 

0 

X 

4 

12 

73 

43 

4 

X 

0 

X 

2 

13 

70 

50 

2 

X 

0 

X 

2 

14 

77 

55 

0 

X 

0 

2 

b 

3 

15 

72 

59 

3 

X 

0 

X 

6 

16 

73 

54 

2 

X 

0 

X 

4 

17 

70 

41 

1 

X 

0 

X 

3 

18 

74 

43 

1 

X 

0 

X 

2 

19 

66 

49 

2 

X 

2 

X 

2 

20 

66 

53 

0 

X 

2 

e 

X 

1 

21 

64 

50 

0 

3 

b 

1 

X 

5 

22 

60 

38 

2 

1 

X 

1 

X 

2 

23 

50 

43 

0 

0 

X 

0 

X 

0 

24 

58 

43 

2 

0 

X 

0 

X 

0 

25 

58 

40 

2 

1 

X 

0 

X 

2 

26 

54 

44 

0 

0 

X 

0 

X 

2 

27 

62 

37 

0 

1 

X 

1 

X 

0 

28 

60 

31 

0 

0 

X 

1 

X 

1 

APHIS  RUMICIS 


33 


TABLE  VI  (Cont.)     Aphis  rumwis— 1923— Bustleton,  Pa. 


Temp. 

First-born 

Last-born 

Generation  Series 

Gen.  Series 

Date 

Max 

Min. 

1-17 

1-18 

1-19 

2-16 

2-17 

2-18 

2-19 

l-8f 

l-8g 

Oct.   29 

67 

48 

0 

2 

X 

4 

X 

1 

30 

72 

46 

1 

3 

X 

3 

X 

4 

31 

65 

42 

0 

2 

X 

0 

X 

2 

b 

Nov.    1 

48 

30 

0 

0 

X 

d 

X 

0 

X 

2 

53 

27 

0 

0 

X 

X 

0 

X 

3 

60 

26 

0 

0 

X 

2 

b 

d 

X 

4 

63 

27 

1 

1 

X 

1 

X 

X 

5 

63 

53 

0 

0 

X 

1 

X 

X 

6 

57 

46 

1 

3 

X 

1 

X 

X 

7 

50 

43 

1 

d 

X 

1 

X 

X 

8 

47 

37 

0 

X 

1 

X 

X 

9 

44 

26 

0 

X 

0 

X 

X 

10 

51 

24 

0 

X 

0 

X 

X 

11 

58 

31 

1 

X 

1 

X 

X 

12 

51 

39 

1 

X 

1 

X 

X 

13 

53 

34 

0 

X 

1 

X 

X 

14 

60 

37 

0 

X 

0 

X 

X 

15 

49 

35 

0 

X 

1 

X 

X 

16 

48 

42 

0 

X 

0 

X 

X 

17 

49 

40 

0 

X 

1 

X 

X 

18 

51 

39 

0 

X 

0 

X 

X 

19 

41 

30 

1 

X 

1 

X 

X 

20 

48 

20 

1 

X 

0 

X 

X 

All  experiments  terminated  Nov.  20. 

On  Nov.  20: 

1-17    Apterous  viviparous  female  alive. 

1-19    PupSB  of  males  with  wing  pads. 

2-18    Apterous  viviparous  female  alive. 

2-19    Practically  mature  apterous  viviparous  female. 

l-8g    Nymphs  in  3rd  and  4th  instar. 

First  hard  frost  Nov.  6-10. 


34  IOWA  STUDIES  IN  NATURAL  HISTOEY 

variations  greater  than  those  found  in  a  collection  of  individuals 
reared  from  known  stock  on  one  host  such  as  Rumex  crispus,  I 
concluded  that  these  belong  to  the  one  species,  Aphis  rumicis  Linn. 
The  question  as  to  the  possibility  of  physiological  species  being 
present  on  different  hosts  has  been  suggested,  but  my  experiments 
seem  to  indicate,  as  did  Davidson's  that  such  is  not  the  case.* 
In  the  cage  experiments,  sexuparae  from  Chenopodium  migrated 
to  Euonymus  and  oviparse  developed  and  laid  eggs  on  the  Euony- 
mus while  eggs  were  also  secured  on  Chenopodium  album  from  the 
same  strain.  Strains  from  Chenopodium  album  laid  eggs  on 
Viburnum  opulus  and  those  from  Madura  pomifera  produced  eggs 
on  Rumex  crispus. 

NUMBER  OF  GENERATIONS 
During  the  seasons  of  1920-21-22-23,  eight  first-born  generation 
series  were  conducted.  The  data  obtained  from  two  series  of  1923 
are  presented  in  Table  VI.  Series  1  was  started  by  collecting  eggs 
on  Chenopodium  album  which  had  remained  out  of  doors  all  winter. 
These  eggs,  on  small  bits  of  the  dried  stems,  were  brought  into  the 
insectary  March  27  and  placed  on  the  soil  at  the  base  of  potted 
plants  of  Rumex  crispus.  The  first  eggs  hatched  on  April  4  and 
the  young  began  feeding  on  the  leaves  of  the  Rumex.  The  ex- 
periments were  transferred  to  the  insectary  on  April  27  and  all 
succeeding  generations  were  reared  out  of  doors.  All  generations 
of  Series  1  were  reared  on  Rumex  crispus  and  Rumex  obtusifolius. 
From  April  4  to  Nov.  20,  the  date  the  experiments  were  closed, 
twenty  first-born  generations  occurred  in  this  series.  The  series 
closed  with  a  male  in  the  last  nymphal  instar.  During  the  sum- 
mer, a  total  of  six  days  were  lost,  three  days  between  generations 
12  and  13  and  three  between  13  and  14. 

Series  2  was  started  with  a  mature  stem  mother  taken  from 
Viburnum  opulus  on  April  27.    It  is  probable  that  this  individual 


*  Additional  transfer  experiments  conducted  during  the  spring  of  1924, 
confirm  my  contention  that  physiological  strains,  confined  to  certain  host 
plants,  are  not  demonstrable.  Stem  mothers  in  the  first  instar  from  eggs  on 
Viburnum  opulus  were  transferred  to  Bumex  obtusifolius.  These  aphids  ma- 
tured normally  on  this  food  plant  and  individuals  of  the  third  viviparous 
generation  were  present  when  the  experiment  closed.  Stem  mothers  in  the 
first  instar  taken  on  Bumex  obtusifolius  in  the  field,  contemporaneous  with 
hatching  of  eggs  on  Viburnum,  matured  and  founded  colonies  on  Bumex  in 
the  insectary.  Progeny  from  this  stem  mother  on  Bumex  were  successfully 
transferred  to  Viburnum  opulus,  Euonymus  alatus,  Celastrus  scandens,  Madura 
pomifera,  and  Philadelphus  coronarius. 


APHIS  RUMICIS 


35 


hatched  from  the  egg  about  April  10  and  matured  April  25.  First- 
born young  which  were  two  days  old,  comprising  the  second  gen- 
eration, were  taken  with  the  stem  mother.    Series  2  closed  on  Nov. 

20  with  a  male  nymph  of  4th  instar.  This  aphid  was  an  individual 
of  the  twentieth  first-born  generation  of  an  unbroken  series.  The 
first  individual  in  Series  2  matured  on  Viburnum.  Generations 
2  to  15  inclusive  were  reared  on  Rumex  crispus.  Generations  16 
to  20  inclusive  were  reared  on  Chenopodium  album. 

The  remaining  six  series  of  the  total  of  eight  were  incomplete 
in  that  each  was  started  with  a  winged  migrant  taken  from  one 
of  the  summer  food  plants  in  the  field.  The  possible  number  of 
generations  which  might  obtain  in  the  case  of  each  series  has  been 
determined  by  combining  the  number  obtained  in  each  series  with 
the  probable  number  of  generations  occurring  before  the  date  the 
series  started.  The  probable  previous  number  of  generations  was 
obtained  by  a  comparison  of  the  date  of  starting  with  the  number 
of  the  generation  maturing  on  the  nearest  date  to  this  in  series 
2  for  1923.  The  summary  of  these  data  will  be  found  in  Table 
VII.  It  will  be  noted  that  from  the  eight  separate  series,  *me  had 
a  possible  17  first-born  generations,  two  had  18  first-born  genera- 
tions, two  19  generations,  two  had  20  generations,  and  one  had 

21  generations,  the  model  number  of  the  eight  series  being  19. 

A  last-born  of  last-born  series  was  started  on  July  14  from  the 
individual  born  in  generation  9  of  series  1.  The  series  was  closed 
on  Nov.  20  with  the  7  generations.    During  this  same  time  11  first- 


TABLE  VII 


Date  of  Experiment 

No.  Generations 

Possible  No. 
of  Generations 

1920 

August  19  to  November  12 

1921 

May  21  to  November  11 

1922 

May  30  Fo  November  10 
June  30  to  November  10 
July  14  to  November  10 

1923 

April  4  to  November  20 
April  10  to  November  20 
June  2  to  November  20 

8 

15 

13 
12 
10 

20 
20 
14 

21 

18 

17 
19 
19 

18 

36 


IOWA  STUDIES  IN  NATURAL  HISTORY 


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38  IOWA  STUDIES  IN  NATURAL  HISTORY 

born  generations  had  occurred  in  Series  1.  From  this  known  ratio 
between  the  number  of  first-born  and  last-born  generations,  we  may 
conclude  that  Aphis  rumicis  would  have  a  minimum  of  12  genera- 
tions for  the  entire  season. 

MOLTING 
Aphis  rumicis,  like  most  other  aphids,  molts  four  times  or  passes 
through  four  nymphal  instars  before  it  reaches  maturity.  My 
observations,  covering  four  consecutive  years,  indicate  that  the 
general  trend  is  for  the  individual  to  m,olt  between  daylight  and 
9 :00  A.  M.  This  is  not  invariable,  since  some  individuals  molted 
later  during  the  day,  but  never  at  night.  The  following  figures 
represent  data  obtained  from  experiments  covering  the  months  of 
June,  August  and  September.  The  length  of  the  first  instar  in  40 
eases  ranged  from  1  day  to  3  days  with  a  mean  period  of  2  days. 
The  period  between  the  first  molt  and  second  molt  varied  from  2 
days  to  4  days  with  a  mean  of  2  days  in  27  cases.  The  mean  period 
for  the  third  instar  was  2  days  for  27  cases  with  a  range  from  1  day 
to  6  days.  The  mean  length  of  time  spent  in  the  fourth  instar  was 
2  days  in  21  cases  with  a  range  of  1  day  to  6  days.  The  length  of 
time  elapsing  from  the  date  of  the  last  molt  to  the  birth  of  the  first 
young  varied  from  0  days  to  9  days  with  a  mean  for  14  cases  of 
1  day.  All  individuals  in  these  experiments  which  reached  ma- 
turity were  apterous  females.  The  mean  length  of  the  second, 
third  and  fourth  instars  for  September  was  3  days.  This  is  to  be 
correlated  with  the  data  in  Table  VIII  which  shows  that  the  gener- 
ations in  the  fall  required  a  greater  length  of  time  to  reach  ma- 
turity than  did  those  which  matured  in  mid-summer. 

AGE  AT  WHICH  FEMALES  REPRODUCE 
The  length  of  time  which  was  consumed  by  viviparous  females 
from  birth  until  they  gave  birth  to  their  first  progeny  varied  ac- 
cording to  the  time  of  year  in  which  they  appeared.  This  period 
ranged  from  seven  days  in  July  or  August,  to  twenty  days  in  late 
October  and  early  November.  The  mean  length  of  the  develop- 
mental period  was  10.5  days  for  all  seasons  of  the  year.  These 
figures  represent  119  individuals  reared  in  1920,  1921,  1922,  and 
1923.  It  will  be  noted  that  this  difference  in  the  length  of  the 
developmental  period  is  seasonal  by  referring  to  Table  IX.  In 
this  table  the  mean  length  of  the  developmental  period  has  been 
determined  for  individuals  grouped  according  to  date  of  birth. 


APHIS  RUMICIS  39 

The  limits  of  these  several  groupings  were  arbitrarily  selected  and 
all  individuals  born  or  developing  within  limits  of  any  one  group 
were  classed  together.  The  cases  represent  records  covering  the 
four  seasons  from  1920  to  1923. 

TABLE  IX 

Period  of  Birth  Dev.  Period  No.  of  Individuals 

April  4  to  June  15  11.(5  16  cases 

June  15  to  August  20  9.0  37  cases 

August  20  to  November  4  11.6  43  cases 

It  will  be  seen  that  the  individuals  born  from  April  4  to  June  15 
had  a  mean  developmental  period  of  11.6  days;  those  born  between 
June  15  and  August  20  had  a  mean  developmental  period  of  9.0 
days ;  those  born  between  August  20  and  November  4  had  a  mean 
developmental  period  of  11.6  days. 

The  data  which  are  given  above  for  Aphis  rumicis  agree  very 
closely  with  information  obtained  in  the  same  laboratory  on  Myzus 
persicce.  The  average  age  of  65  mothers  of  Myzus  persicce  was 
found  to  be  10.2  days  and  the  seasonal  range  was  practically  the 
same,  i.e.  11  days  in  spring  and  fall,  and  9  days  in  summer. 

This  variation  in  the  age  of  females  of  Aphis  rumicis  at  the 
birth  of  the  first  progeny  is  illustrated  in  digrammatic  form  by 
Plate  I,  B.  In  this  figure  the  lower  solid  line  shows  the  variation 
in  the  age  of  females  at  birth  of  first  young  for  first  born  genera- 
tions in  1923.  The  upper  dotted  line  represents  the  mean  tem- 
peratures which  obtain  for  each  of  these  developmental  periods 
for  the  several  generations.  In  general,  the  trend  shows  that  in 
the  spring  and  fall  when  temperatures  are  low  the  developmental 
period  is  fairly  long,  while  in  the  summer  when  mean  temperatures 
are  higher  the  insects  mature  in  much  shorter  time. 

REPRODUCTION 
The  shortest  period  of  reproduction,  for  a  single  female  under 
observation  in  any  one  of  the  four  seasons,  was  3  days.  Several 
cases  were  recorded  in  which  the  period  extended  over  4  days  in 
August  and  some  in  which  the  period  was  5  days  in  July.  One 
female,  born  on  Sept.  22,  1923,  was  bearing  young  on  Nov.  20 
when  the  experiment  closed.  The  reproduction  period  for  this 
individual  covered  47  days.  Other  individuals,  having  a  repro- 
duction period  of  25  to  32  days  were  common  in  late  September, 


40  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

October,  and  November.  The  average  length  of  reproductive 
period  for  79  females  was  12.6  days.  I  found  that  the  total  num- 
ber of  young  produced  by  a  female  during  her  lifetime  ranged 
from  2  to  105  aphids  with  an  average  of  24.6  young  per  mother 
for  76  individuals.  Only  those  individuals  were  considered  in 
securing  this  average  which  died  from  natural  causes  at  a  definitely 
determined  date.  The  maximum  number  of  young  borne  by  one 
mother  in  a  single  day  was  13..  This  mother  was  feeding  on 
spinach  during  May.  Four  other  individuals  each  produced  a 
maximum  of  11  young  in  one  day.  The  average  number  of  young 
born  to  one  female  in  a  day  was  2.1,  average  obtained  from  119 
cases. 

LONGEVITY 
The  length  of  life  of  females  after  the  birth  of  the  last  young 
varied  considerably  averaging  2.2  days  for  78  cases.  Six  females 
died  on  the  same  day  on  which  they  gave  birth  to  the  last  young. 
One  female  lived  12  days  after  the  birth  of  the  last  young  and  two 
individuals  lived  9  days.  The  total  length  of  life  of  individual 
females  in  the  generation  experiments  ranged  from  10  days  to  48 
days.  The  average  length  of  life  for  76  females  was  23.3  days. 
It  may  be  noted  that  the  average  length  of  life  of  Myzus  persicw 
was  found  to  be  23.5  days  in  work  done  on  that  species  at  the  same 
laboratory. 

THE  OCCUEEENCE  OF  ALATE  FOEMS 
In  general  the  winged  viviparous  females  of  Aphis  rumicis  may 
be  grouped  as  spring  migrants,  migrants  appearing  during  the 
summer  generations,  and  fall  migrants.  The  appearance  of  the 
spring  and  fall  migrants  is  fairly  constant  and  may  be  looked  for 
(within  a  certain  range)  at  about  the  same  time  each  year.  The 
appearance  of  summer  migrants,  on  the  other  hand,  does  not  seem 
to  be  so  definitely  defined  and  may  or  may  not  appear  in  any  given 
summer  generation.  In  my  rearing  cages  considerable  numbers  of 
the  daughters  of  stem  mothers  from  Viburnum  series  No.  2  became 
winged  adults  on  May  8  to  11,  1923.  On  May  8  of  the  same  year, 
the  first  winged  female  was  taken  on  the  flower  spikes  of  Rumex 
crispus  in  the  field.  In  the  same  experiment,  90%  of  all  grand- 
daughters of  stem  mothers  or  the  daughters  of  the  wingless  females 
of  the  second  generation  became  winged  viviparae  on  May  23.  The 
first  winged  forms  to  appear  in  the  series  No.  1  on  Rumex,  from 
stem  mothers  hatched  from  eggs  on  Chenopodium  stems  and  reared 


APHIS  EUMICIS  41 

for  the  first  two  generations  in  the  laboratory,  were  of  the  4th 
generation,  i.e.,  were  great  grand  daughters  of  the  stem  mothers. 
These  individuals  matured  May  24  on  Rumex  crispus  with  92% 
winged.  Thus,  winged  forms  from  the  Viburnum  strain  appeared 
in  predominating  numbers  in  the  3d  generation  and  in  the  Cheno- 
podium  strain  on  Rumex  in  the  4th  generation,  but  they  matured 
simultaneously  in  the  insectary.  The  field  collections  for  four  years 
also  indicate  that  the  predominating  spring  migration  takes  place 
about  the  third  week  in  May,  and  that  the  earlier  migrants  noted 
in  early  May,  were  comparatively  of  much  smaller  numbers.  Prac- 
tically all  individuals  which  were  taken  were  migrants  on  Viburnum 
on  May  21,  1920  and  again  on  May  21,  1922.  Migrants  were  noted 
as  leaving  Euonymus  atropurpureus  on  May  22,  1922.  The  first 
record  of  migrants  and  young  on  a  summer  host  plant,  Rumex 
crispus,  in  1922,  was  taken  on  May  21.  Infestation  by  migrants 
and  young  on  lima  beans  was  noted  at  Bustleton,  Penn.,  on  May 
31, 1920.  Light  infestation,  started  by  migrants  on  Arctium  lappa, 
was  noted  at  Iowa  City,  Iowa,  on  May  22,  1922.  First  infestations 
on  Chenopodium  album  in  the  spring  were  on  May  31, 1922  and  on 
June  6,  1923.  It  will  be  seen  that  these  typical  records,  and  many 
others  of  a  similar  nature,  in  my  files,  show  that  an  obvious  rela- 
tionship exists  between  the  aphids  migrating  from  Viburnum, 
Euonymus  and  other  plants  in  the  spring  and  the  migrants  ap- 
pearing at  the  same  time  on  Chenopodium,  Rumex  and  Arctium 
lappa. 

Neither  the  records  made  on  generation  experiments  nor  notes 
taken  at  time  field  collections  were  made,  serve  to  clarify  the 
problem  as  to  what  actually  induces  the  appearance  of  winged 
forms  during  the  summer.  In  my  rearing  experiments,  these 
winged  forms  appeared  from  time  to  time,  but  in  no  definite  gener- 
ation or  time  of  the  season.  No  correlation  was  found  between 
date  of  appearance  and  host  plant  or  possible  differences  in  ma- 
terials in  plant  sap.  I  found  that  in  Series  1  on  Rumex  crispus 
all  young  matured  into  apterous  viviparae  from  the  5th  generation 
to  the  12th  generation.  In  the  12th  generation,  maturing  on  July 
31,  1923,  3  out  of  9  individuals  or  33%  were  winged.  In  Series 
2  on  Rumex  crispus,  individuals  of  the  4th  and  5th  generations 
matured  into  wingless  females,  but  25%  of  the  adults  comprising 
generation  six  in  this  series  matured  into  winged  viviparae  on  June 
18,  1923.    In  Series  3,  generation  6  (10th  in  line),  on  Chenopodium 


42  IOWA  STUDIES  IN  NATURAL  HISTORY 

album,  4  out  of  8  individuals  became  winged  viviparae  on  July  24, 
1923.  In  this  same  series  on  Chenopodium  album,  winged  indi- 
viduals appeared  on  Sept.  14,  1923.  At  this  time,  all  forms  ma- 
turing in  Series  1  and  2  were  wingless.  In  this  grouping,  the 
winged  individuals  appearing  from  June  1  to  Sept.  15-20  have 
been  considered  as  summer  migrants.  By  referring  to  collection 
records  in  the  food  plant  list  it  will  be  noted  that  winged  viviparae 
were  taken  during  each  of  the  months  from  June  to  October  on  a 
wide  range  of  host  plants.  I  feel  that  the  appearance  of  the  fall 
migrants  or  winged  sexuparae  is  more  or  less  linked  up  in  some  way 
with  temperature  since  they  appear  consistently  in  regions  of  the 
United  States  with  decline  of  mean  temperature  in  the  fall  of  the 
year,  but  do  not  appear  in  California  where  fall  does  not  bring 
such  a  low  temperature.  It  may  be  as  Davidson  (18)  suggests, 
that  it  is  attributable  to  some  combination  of  internal  factors,  but 
the  direct  stimulus  would  seem  to  be  climatic  in  nature.  In  my 
experiments  winged  sexuparae  matured  Oct.  23,  1921,  on  Cheno- 
podium album,  on  Oct.  27, 1923,  in  Series  3  on  Chenopodium  album, 
in  the  18th  first  born  generation,  and  in  Series  1  on  Oct.  20-25, 
1923,  on  Rumex  crispus  all  but  8  out  of  9  became  winged  sexuparae. 
In  the  field,  collections  were  made  of  winged  sexuparae  maturing 
on  summer  hosts/  from  Oct.  6  to  Oct.  31  and  alighting  and  bearing 
young  on  winter  hosts  during  the  same  period. 

Recent  experimental  work  on  this  particular  problem  has  re- 
sulted in  evidence  which  is  largely  contradictory  in  nature.  Mason 
(55)  found  that  changes  of  environment  with  which  he  worked,  i.e., 
effect  of  injury  to  food  plants,  crowding,  and  the  addition  of 
chemical  solutions'  to  food  plants,  had  no  bearing  on  production  of 
winged  forms  in  the  first  generation.  He  concluded  that  the  young 
aphid,  when  born,  has  its  adult  condition  as  regards  presence  or 
absence  of  wings  already  determined  and  that  there  is  no  positive 
evidence  in  favor  of  such  influences  even  to  the  third  generation. 
Uichanco  (94)  failed  to  obtain  fall  migrants  of  Aphis  rumicis  when 
forms  were  reared  in  the  greenhouse  under  optimum  temperature 
conditions.  Wadley  (96)  concluded  that  the  factors  of  nutrition, 
parentage,  and  temperature  were  all  important  in  causing  appear- 
ance of  winged  forms,  but  that  these  factors  must  be  applied  before 
the  second  molt. 


APHIS  RUMICIS  43 

APPEARANCE  OF  SEXES 

It  is  only  within  recent  years  that  any  winter  hosts,  other  than 
Euonymus  europceus  and  Viburnum  opulus  have  been  known  to 
be  selected  by  Aphis  rumicis.  Theobald  (88)  reported  finding  the 
eggs  on  petioles  of  Rumex  crispus,  but,  so  far  as  I  can  learn,  did 
not  observe  the  hatching  of  these  eggs  and  founding  of  the  colony 
by  the  stem  mother  the  following  season.  Davidson  (17)  reported 
the  rearing  of  sexes  on  broad  beans  and  Euonymus  europceus  under 
controlled  conditions  and  cites  records  of  sexual  females  oviposit- 
ing on  sugar-beet  (Gaumont)  (1913)  and  on  haricot  beans  (Mala- 
guin  and  Moitre)  (1914).  Davidson  made  this  further  observa- 
tion: "The  spindle-tree  is  undoubtedly  a  winter  host  of  Aphis 
rumicis,  but  considering  the  local  distribution  of  Euonymus  in 
Britain  it  is  highly  probable  that  there  are  other  winter  hosts.' ' 
I  was  so  forcibly  impressed  by  the  same  idea  when  I  began  these 
studies  that  I  made  very  careful  collections  from  shrubs  and  sum- 
mer hosts  of  A.  rumici*  in  order  to  ascertain  these  other  possible 
hosts.  Conclusions  as  to  the  names,  which  should  be  included  as 
winter  hosts  are  based  on  careful  determinations  of  field  collections, 
transfer  tests,  and  copulation  experiments.  I  have  conducted  many 
tests  in  which  I  selected  a  male  taken  from  a  certain  host  plant  and 
placed  it  on  a  plant  upon  which  an  oviparous  female  was  feeding. 
In  many  cases  this  experiment  was  reversed  and  the  oviparous 
female  from  a  certain  host  was  crossed  with  a  male  from  a  different 
host.  Although  I  realize  that  results  of  such  copulation  experi- 
ments are  not  of  themselves  entirely  conclusive  it  seems  that  such 
information  is  not  only  interesting,  but  desirable  when  it  is  cor- 
related with  results  of  transfers  made  at  other  times  during  the 
year.  In  some  of  the  cases  the  individuals  which  were  paired  were 
taken  from  different  host  plants.  In  other  cases  these  pairings 
were  made  between  males  and  oviparous  females  from  the  same 
host  plant.  I  have  been  unable  to  find  in  literature  any  mention 
of  similar  experiments  with  this  species.  The  cases  in  which  suc- 
cessful copulation  was  effected  are  listed  in  Table  X.  In  some 
cases  the  male  was  transferred  to  the  plant  upon  which  the  ovi- 
parous female  was  feeding  by  means  of  a  small  brush,  and  the 
transfer  in  this  case  was  somewhat  aided.  In  other  cases  the  plant 
upon  which  the  male  was  feeding  was  placed  inside  a  large  cage 
together  with  the  plant  upon  which  oviparae  were  feeding.  In  this 
ease  the  males  migrated  to  the  host  of  the  oviparse  themselves.  Only 
cases  in  which  actual  copulation  was  effected  are  listed. 


44 


IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  X— COPULATION  TESTS 


No.  of 

Date 

Host  of  Male 

Host  of  Female 

cases 

Oct.  18 

Chenopodium  album 

Viburnum  opulus 

1 

Oct.  20 

a                 » 

19                     ?? 

2 

Oct.  25 

y  y                     >  y 

J>                     >> 

6 

Oct.  25 

yy                     ff 

?>                     ?? 

6 

Oct.  15 

>>                      y  y 

Euonymus  alatus 

1 

Oct.  23 

?;                      >  > 

Chenopodium  album 

6 

Oct.  28 

?  ?                      >  > 

99              yy 

4 

Oct.  23 

Arctium  lappa 

Bumex  crispus 

2 

Oct.  28 

^>            >  > 

99          >> 

1 

Oct.  28 

?>            ?  ? 

Arctium  lappa 

5 

Nov.  29 

Bumex  crispus 

Bumex  crispus 

several 

Oct.  23 

Viburnum  opulus 

Viburnum  opulus 

4 

Oct.  30 

j>            >> 

Euonymus  alatus 

2 

Oct.  29 

Euonymus   alatus 

yy              yy 

2 

Oct.  30 

19                      M 

Viburnum  opulus 

1 

Oct.  23 

Madura  pomifera 

Madura  pomifera 

several 

Oct.  24 

i  y             ?> 

Viburnum  opulus 

1 

In  the  field,  during  October,  I  have  taken  males  and  oviparous 
females  in  copulation  on  Arctium  lappa,  Chenopodium  album, 
Viburnum  opulus,  Euonymus  alatus,  Madura  pomifera,  Celastrus 
scandens,  and  Philadelphus  coronarius.  Sexes  were  also  taken  dur- 
ing October  from  Bumex  crispus,  Hydrangea  paniculata  and  Caly- 
canthus  fertilis  which  agreed  morphologically  with  the  same  forms 
taken  in  copulation  on  the  other  hosts.  It  thus  appears  as  David- 
son has  suggested  that  the  number  of  winter  hosts  of  Aphis  rumicis 
is  quite  numerous. 

In  America,  the  winter  hosts  which  have  been  recorded,  in  addi- 
tion to  Euonymus  and  Viburnum,  include  Celastrus  scandens  and 
Hedera  in  Conn.,  Patch  (10)  and  Philadelphus  coronarius  in  New 
York,  Ohlendorf  (62).  Ohlendorf  substantiated  records  of  Phila- 
delphus, Viburnum  and  Euonymus  by  transfers  between  these 
hosts. 

I  found  that  the  migrants,  which  are  the  progeny  of  apterous 
viviparae  on  summer  hosts,  were  the  winged  sexuparaa  which  give 
birth,  to  oviparous  females.  These  oviparse  are  born  and  develop 
either  on  some  of  the  herbaceous  hosts  such  as  Rumex  obtusifolius, 
Bumex  crispus,  Chenopodium  album  and  Arctium  lappa  or  on  the 
woody  shrubs  such  as  Euonymus  atropurpureus,  Viburnum 
opulus,  Philadelphus  coronarius,  Hydrangea  paniculata,  Celastrus 
scandens,  Maclura  pomifera,  etc.  The  males  are  the  progeny  of 
apterous  sexuparce  and  develop  on  the  so-called  summer  hosts.  The 
offspring  of  these  apterous  sexuparaa  are  not  always  males  exclu- 


APHIS  RUMICIS  45 

sively.  In  my  experiments,  males,  migrants  or  winged  sexuparae, 
and  apterous  sexuparae  were  born  by  the  same  mother.  The  sexu- 
parae, males,  and  oviparous  females  develop  during  October  and 
early  November  in  Iowa  and  Pennsylvania. 

It  should  be  noted  that  Swain  (84)  did  not  take  the  true  sexes 
of  Aphis  rumicis  in  California  but  found  it  developing  partheno- 
genetically  throughout  the  year  on  its  summer  hosts.  I  reared  this 
species  in  the  greenhouse  on  Rurnex  crispus  from  Sept.  1921  to 
June  1922.  At  no  time  did  true  sexes  appear  in  these  cages. 
Davidson,  (17)  under  similar  conditions  in  England,  obtained  a 
certain  proportion  of  sexual  forms  in  five  succeeding  generations. 

COPULATION  AND  EGG-LAYING 
A  male  may  copulate  with  more  than  one  female.  A  male  was 
observed  to  copulate  with  two  separate  females  on  the  same  plant. 
An  interval  of  fifteen  minutes  to  one-half  hour  elapsed  between 
the  times  of  copulation  in  three  different  cases  under  observation. 
When  the  male  approached,  the  female  elevated  the  tip  of  the 
abdomen  and  moved  the  hind  legs  vigorously  about  in  the  air.  In 
several  cases  after  mounting  the  female,  the  male  was  observed 
attempting  to  insert  the  penis  at  the  head  of  the  female.  Failing 
in  this,  the  male  turned  slowly  about  and  successfully  completed 
the  act. 

A"  series  of  experiments  was  conducted  to  secure  data  on  the 
number  of  eggs  laid  by  a  single  female.  At  the  time  the  experi- 
ments closed  on  November  21,  all  females  still  living  were  dissected 
and  the  number  of  ova  still  within  the  body  were  counted,  (Table 
X).  A  series  of  ten  grown  females  reared  on  CJienopodium  album 
was  dissected  on  Nov.  12  and  the  number  of  ova  was  counted.  The 
counts  were  as  follows:  1,  8  ova;  2,  7  ova;  3,  6  ova;  4,  6  ova;  5, 
5  ova ;  6,  8  ova ;  7,  7  ova ;  8,  5  ova ;  9,  5  ova ;  10,  6  ova.  The  mean 
in  this  case  is  6.3  ova  per  female. 

From  my  observations  of  cage  experiments,  the  oviparous  female 
does  not  deposit  all  of  her  eggs  at  one  time,  but  the  period  of  egg 
deposition  is  extended  over  a  period  of  one  to  two  weeks.  The 
eggs  when  first  laid  are  olive  green  in  color.  The  coat  hardens 
and  within  a  day  becomes  shiny-black.  Eggs  which  are  laid  upon 
the  woody  winter  hosts  such  as  Viburnum  opulus,  etc.,  are  usually 
placed  in  the  axils  between  the  bud  and  the  stem.  On  Rumex 
crispus  and  Rumex  obtusifolius  they  are  fastened  by  the  mucilag- 
inous secretion  to  the  underside  of  the  leaf,  usually  along  the 


46 


IOWA  STUDIES  IN  NATURAL  HISTORY 


petiole  or  mid  vein.  On  Chenopodium  album,  the  eggs  may  be 
found  tucked  into  old  scars  or  breaks  in  the  stem,  in  the  axils 
formed  by  the  side  branches  with  the  main  stem,  and  even  glued 
up  and  down  the  main  stem  unprotected. 


TABLE   XI 


Food  Plant  of 

Exp. 

Copulation 

No.  of  eggs 

Notes 

Ovip.  Female 

started 

with  male 

Nov.  21 

Rumex  obtusifolius 

Oct.   22 

Oct.   25 

5 

dead     $ 

Bnmex  obtusifolius 

Oct.   25 

Oct.   31 

1 

dead     $ 

Chenopodium  album 

Oct.   25 

Oct.   25 

2 

dead     $ 

Chenopodium  album 

Oct.   25 

Oct.   25 

8 

3  in     $ 

Bumex  crispus 

Oct.   25 

Oct.   25 

2 

0  in     $ 

Chenopodium  album 

Oct.   31 

Oct.   31 

3 

2  in     $ 

Chenopodium  album 

Oct.   31 

Nov.    2 

4 

1   in      $ 

Oviparous  females  taken  from  Madura  pomifera  while  in  the 
fourth  instar,  were  transferred  to  Rumex  obtusifolius  Oct.  22. 
These  matured  on  Rumex  and  deposited  eggs.  Oviparous  females 
taken  from  Chenopodium  album  Oct.  16,  when  transferred  to 
Euonymus  atropurpureus,  matured  and  oviposited  on  Euonymus. 

The  question  arises  as  to  whether  development  of  oviparae  on 
herbaceous  plants  and  consequent  egg  deposition  on  the  same  is 
accidental  in  some  cases,  the  chance  result  of  migrants  alighting 
on  these  plants.  Although  this  may  have  been  the  case  with  Aphis 
rumicis  at  some  previous  stage  in  its  development,  I  have  come  to 
believe  that  here  in  the  Eastern  and  Central  United  States,  at  least, 
it  is  an  adaptation  which  helps  to  insure  perpetuation  of  the  species. 
Rumex  crispus  and  Rumex  obtusifolius  are  perennials  and  some 
of  the  rosettes  of  leaves  never  entirely  die,  but  survive  the  winter. 
Other  new  leaves  are  shot  out  at  the  earliest  advent  of  spring. 
Aphids  hatching  in  April,  from  eggs  deposited  on  either  of  these 
plants,  find  the  food  necessary  for  development.  I  have  taken  stem 
mothers  on  Rumex  crispus  and  Rumex  obtusifolius  in  the  spring  at 
the  same  time  they  were  found  on  Euonymus  and  Viburnum.  In 
the  case  of  aphids  hatching  from  eggs  on  Chenopodium  album ,  it 
is  different  for  this  is  an  annual.  However,  it  must  be  remembered 
that  Chenopodium  album  is  invariably  found  in  the  same  habitat 
with  these  two  species  of  Rumex.  It  is  then  probable  that  the 
aphids  upon  hatching  from  eggs  on  Chenopodium  album  crawl 
down  the  dead  stem  and  seek  nearby  Rumex  plants.  Young  Cheno- 
podium album  plants  are  just  sprouting  at  the  time  the  eggs  hatch. 
This  supposition  is  strengthened  by  the  fact  that  this  very  pro- 


APHIS  RUMICIS  47 

cedurc  took  place  in  my  experiments,  not  in  one  case,  but  in  four- 
teen cases.  I  have  found  no  record  in  the  literature  of  observa- 
tions showing  the  hatching  of  eggs  deposited  on  herbaceous  plants. 
Dr.  Fitch  (32)  found  two  newly-deposited  eggs  on  pigweed 
{Cheno podium  f)  but  regarded  these  as  accidental.  His  notes  under 
heading  of  Aphis  rumicis  Linn.,  December,  1870  read:  " Where  the 
eggs  are  laid  and  how  the  insect  is  carried  through  the  winter,  has 
hitherto  been  a  mystery,  as  Mr.  Curtis  observes.  Upon  this  im- 
portant point  I  am  able  to  shed  some  light.  Upon  examining  a 
pigweed  infested  by  these  black  lice  the  latter  part  of  October  I 
discovered  an  eggy  slightly  adhering  to  the  surface  of  a  dry  and 
crinkled  and  dead  leaf,  and  another  crowded  into  a  crevice  in 
another  wrinkled  dead  leaf,  whereby  only  its  end  was  visible.  These 
no  doubt  had  been  newly  laid.  They  were  of  a  dull  green  color, 
smooth  and  shining.  Several  other  infested  weeds  were  examined 
later  in  the  season,  but  I  was  unable  to  detect  any  eggs  upon  them. 
In  November,  meeting  with  a  weed  that  was  thronged  with  pupae, 
I  transplanted  it  into  a  flower  pot  and  brought  it  in  doors  to  ob- 
serve whether  on  maturing,  having  no  other  place  to  lay  their  eggs, 
they  would  not  stock  this  plant  with  them.  But  on  obtaining 
wings,  they  all  flew  away,  without  making  any  deposit  of  eggs 
thereon.  It  was  thus  evident  that  the  two  eggs  I  found  were  only 
placed  on  the  dead  leaves  by  accident,  and  that  they  do  not  lay 
their  eggs  upon  the  plants  they  inhabit,  or  at  least  upon  those 
which  decay  at  the  close  of  the  season. ' ' 

SEASONAL  HISTORY 
I  have  outlined,  in  tabular  form,  the  host  plants  upon  which  I 
have  collected  Aphis  rumicis  at  different  periods  of  the  year.  This 
indicates  the  general,)  occurrence  of  this  aphid  as  I  have  found  it 
during  the  various  seasons  in  Pennsylvania.  I  found  that  the 
eggs  on  Viburnum  opulus  and  Chenopodium  album  hatched  about 
the  second  week  in  April.  The  young  stem  mothers  on  Viburnum 
opulus  developed  on  that  host  while  those  from  eggs  on  Cheno- 
podium album  migrated  of  necessity  to  Rumex.  Stem  mothers 
were  found  developing  on  Rumex  in  the  field  during  the  third  week 
in  April.  Migrant  daughters  of  stem  mothers  on  Viburnum  opulus 
preferred  Rumex  upon  which  to  establish  colonies.  The  migrant 
granddaughters  of  stem  mothers  from  Viburnum  reproduced  on 
Rumex  and  Arctium.  Migrants  from  the  other  winter  hosts  evi- 
dently selected  these  same  plants  since  colonies  were  limited  to 


48 


IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  XII— 

April 

May 

June 

July 

Bwmex  crispus 

Bumex  crispus 

Bumex  crispus 

Bumex  crispus 

Chenopodium 

Chenopodium 

Chenopodium 

album 

album 

album 

Euonymus 

Arctium  lappa 

Arctium  lappa 

Arctium  lappa 

atropurpureus 

Viburnum  opulus 

Viburnum  opulus 

Viburnum  opulus 

Euonymus 

Tropceolum 

Tropceolum 

atropurpureus 

minus 

minus 

Euonymus  alatus 

Beta  vulgaris 

Amaranthus 

Amaranthus 

retroflexus 

retroflexus 

Bheum 

Bheum 

rhaponticum 

rhaponticum 

Spinacia 

oleracea 

Phaseolus 

Dahlia  sp. 

limensis 

Bumex 

obtiisifolius 

Ova 

Eundatrices 

Larvcc 


Eundatrices 
Larvce 
Alate  vivip. 
Apter.  vivip. 


Larvce  Larvce 

Alate  vivip.  Alate  vivip. 

Apter.  vivip.  Apter.  vivip. 


APHIS  RUMICIS 


49 


SEASONAL  HISTORY  CHART 


August 

September 

October 

November 

Bumex  crispus 

Bumex  crispus 

Bumex  crispus 

Bumex  crispus 

Chenopodium 

Chenopodium 

Chenopodium 

Chenopodium 

album 

album 

album 

album 

Arctium  lappa 

Chenopodium 

ambrosioides 
Papaver  sp. 

Arctium  lappa 

Arctmm  lappa 

Lycopersicon 

Capsella 

Viburnum 

e8culentum 

bursapastoris 

opulus 

Tropasolum 

Tropceolum 

Stellaria  media 

Euonymus 

minus 

minus 

alatus 

Daucus  carota 

Galinsoga 

Galinsoga 

Madura 

parviflora 

parviflora 

pomifera 

Amaranthus 

Amaranthus 

Phaseolus 

Celastrus 

retroflexus 

retroflexus 

limensis 

scandens 

Bheum 

Gladiolus  sp. 

Viburnum  opulus 

Euonymus 

rhaponticum 

atropurpureus 

Spinacia 

Spinacia 

Euonymus 

Philadelphus 

oleraeea 

oleraeea 

atropurpureus 

coronarius 

Polygonum 

Pisum  sp. 

Euonymus  alatus 

Bumex 

scandens 

obtusifolius 

(dumetorum) 

Dahlia  sp. 

Madura  pomifera 

Phaseolus 

Celastrus  scandens 

vulgaris 

Mirabilis 

Philadelphus 

jalapa 

coronarius 

Aster  sp. 

Hydrangea 
paniculata 

Bumex 

Calycanthus 

obtusifolius 

Ova 


Ova 


Larva  Larvce 

Alate  vivip.  Alate  vivip. 

Apter.  vivip.  Apter.  vivip. 


Larva 

Alate  vivip. 

(sexuparm) 
Apter.  vivip. 

(sexuparos) 
Oviparce 


Larva 

Alate  vivip. 

(sexuparm) 
Apter.  vivip. 

(sexuparm) 
Oviparm 


Males 


Males 


50  IOWA  STUDIES  IN  NATURAL  HISTORY 

Rumex  and  Arctium  during  this  month.  During  June,  July, 
August  and  September,  as  will  be  noted,  a  great  variety  of  hosts 
may  be  infested.  I  was  unable  to  obtain  any  data  which  would 
lead  me  to  believe  that  migrants  from  any  particular  host  were 
selective  in  their  tastes,  or  in  other  words,  that  certain  strains  of 
Aphis  rumicis  depending  on  groups  of  food  plants  have  been 
evolved.  Theobald  (88)  hasi  diagrammed  a  possible  dual  strain  for 
this  species  in  England.  This  conclusion  was  based  on  his  col- 
lections and  observations  in  the  field. 

Fall  migrants  or  sexuparae,  which  are  the  progeny  of  apterous 
viviparous  females,  develop  on  the  summer  hosts  and  in  October 
and  early  November  return  to  winter  hosts  where  they  give  birth 
to  oviparous  females.  Many  of  the  migrants  which  develop  on 
Chenopodium  album  do  not  change  host  species,  but  may  migrate 
to  another  plant  of  the  same  kind.  They  take  up  a  position  on  the 
under  side  of  the  leaf  and  begin  feeding.  Here  the  young  oviparce 
are  born  and  developed  to  maturity.  At  the  same  time  the  apterous 
viviparous  females  on  Chenopodium  album,  feeding  along  the 
smaller  stems  and  flower  corymbs,  are  giving  birth  to  young  which 
develop  into  winged  males.  On  the  under  surface  of  leaves  of 
Rumex  and  Arctium  apterous  viviparse,  alatae,  males  and  oviparous 
females  may  be  taken  at  one  and  the  same  time.  It  is  from  these 
herbaceous  plants  that  some  of  the  males  migrate,  in  late  October 
and  November,  to  Viburnum  opulus,  Euonymus  atropurpureus, 
Hydrangea,  etc.,  and  mate  with  the  mature  oviparse  on  these  plants. 
Egg  deposition  takes  place  in  late  October  and  November.  It  will 
be  noticed  that  Chenopodium  album  appears  in  the  table  for  each 
month  but  May.  In  April,  it  is  only  as  dried  stems,  upon  which 
eggs  are  found,  that  the  plant  is  listed.  The  aphids  have  not  been 
taken  feeding  on  this  host  until  June.  In  October,  Capsella, 
Galinsoga,  and  Stellaria  serve  as  hosts  in  certain  locations  near 
heavily  infested  Chenopodium  plants.  With  the  killing  of  Cheno- 
podium album  by  frost  in  late  October  and  November,  the  apterous 
viviparae  and  young  males  migrate  to  these  plants  and  complete 
their  development.  At  other  times  during  the  summer  these  plants 
have  not  been  recorded  as  hosts  nor  have  I  found  oviparae  or  eggs 
upon  them. 

In  European  countries,  the  spindle-tree  Euonymus  europceus  is 
the  favored  host  but  with  the  absence  of  any  numbers  of  that  shrub 
in  some  sections  of  America,  Aphis  rumicis  has  evidently  adapted 


APHIS  RUMICIS  51 

itself  to  our  conditions  and  hence  the  choice  as  here  described,  of 
such  a  winter  host  as  Chenopodium  album.  Another  difference 
which  this  insect  encountered  in  its  food  plants  was  the  absence 
of  the  poppy  ( Papaver  sp.)  in  the  wild  state  in  Eastern  and  Cen- 
tral United  States. 

NATURAL  ENEMIES 

Aphis  rumicis  does  not  increase  without  check  throughout  the 
season  because  certain  parasitic  and  predaceous  enemies  reduce 
the  numbers,  in  some  instances  destroying  an  entire  colony  on  a 
plant.  The  parasites  are  particularly  common  in  July  and  August. 
I  reared  Asaphes  americana  Gir.  (det  Gahan)  from  parasitized 
aphids  in  August.  This  species  has  been  recorded  as  a  parasite  of 
ApJtis  rumicis  by  Girault  (39).  LysipMebus  testaceipes  Cress, 
(det.  Gahan)  was  bred  quite  frequently  from  Aphis  rumicis.  Al- 
though this  parasite  apparently  has  not  been  coupled  with  rumicis 
in  literature,  Mr.  Gahan  states  that  he  has  frequently  determined 
it  from  this  host.  I  reared  two  species  of  Hymenoptera  which  are 
probably  secondary  parasites:  Pachyneuron  siphonophorce  Ashm. 
(det.  Gahan)  perhaps  a  parasite  of  LysipMebus,  and  a  Cynipid 
of  which  Mr.  Weld  says,  "may  be  Charips,  Hemicrisis,  or  Phcenog- 
typhis."  Specimens  were  also  bred  of  Aphidencyrtus  sp.  (det. 
Gahan)  Mr.  Gahan  says  that  no  species  of  Aphidencyrtus  has  been 
recorded  from  Aphis  rumicis  and  that  it  may  or  may  not  be  a 
secondary  parasite. 

On  June  7, 1923,  many  individuals  of  Aphis  rumicis,  with  orange- 
colored  mites  clinging  to  them,  were  taken  on  Arctium  lappa.  Dr. 
Ewing  wrote  me  about  these  as  follows:  "The  mites  belong  to  a 
species  of  Bocharitia  of  the  family  Erythraeidae  and  are  probably 
the  young  of  one  of  our  common  species.  Mites  of  the  genus 
Bochartia  parasitize  aphids  in  their  larval  stage.  In  the  nymphal 
and  adult  stages  these  mites  are  predaceous. ' ' 

The  predaceous  beetles  which  were  taken  feeding  on  Aphis 
rumicis  were  Megilla  maculata  DeG.,  Adalia  bipunctata  Linn., 
Hippodamia  convergens  Guer.,  and  Coccinella  9-notata  Herbst. 
Larvae  of  syrphid  flies  and  lace-wing  flies  were  taken  devouring 
numbers  of  the  aphids. 

SUMMAEY 

Aphis  rumicis  Linn,  has  been  known  in  literature  under  a  large 
number  of  names  because  of  its  polyphagous  habits  and  because 
of  the  early  belief  that  species  of  aphids  were  largely  confined  to 


52  IOWA  STUDIES  IN  NATURAL  HISTORY 

single  species  of  hosts.  Nineteen  of  these  names  are  listed  here 
as  synonyms.  In  Europe,  the  species  has  been  known  as  a  serious 
pest  of  varieties  of  beans,  Vicia  faba,  Shirley  poppies,  mangolds, 
and  Euonymus.  In  America,  it  seriously  infests  Viburnum  opulus 
in  the  spring,  Euonymus,  nasturtiums,  seed  stalks  of  beets  and 
spinach,  and  horse  beans,  where  this  crop  has  been  introduced.  It 
also  lives  on  a  large  number  of  weeds. 

During  these  studies,  intermediates  of  viviparous  females,  ovi- 
parous females,  and  males  have  been  found  and  described.  The 
spring  and  fall  migrants  are  morphologically  distinct.  Data  from 
cage  experiments  correlated  with  field  notes  have  demonstrated 
the  presence  of  two  distinct  types  of  life  cycles :  one  having  woody 
shrubs  as  primary  hosts  upon  which  ova  are  deposited  and  the 
first  generations  develop  in  the  spring  with  herbaceous  plants  as 
secondary  hosts ;  the  other  having  herbaceous  plants  such  as  C~keno- 
podium  album  and  Rumex  as  primary  hosts  and  other  herbaceous 
plants  with  the  above  named  as  secondary  hosts.  Five  primary 
hosts  have  been  added  to  the  list  upon  which  this  insect  has  been 
known  to  winter  and  these  records  serve  to  clarify  the  reasons  for 
the  prevalence  of  this  insect  in  sections  where  the  primary  hosts, 
previously  reported,  are  scarce.  The  evidence  seems  to  indicate 
that  physiological  species  are  not  present. 

From  the  detailed  life  history  experiments  it  is  found  that  Aphis 
rumicis  Linn,  may  have  a  maximum  of  20  first-born  generations  in 
Pennsylvania  and  a  minimum  of  12  last-born  generations.  The 
model  number  of  first-born  generations  for  four  seasons  was  19. 
The  average  length  of  the  larval  periods  was  2  days  for  the  first 
instar,  2  days  for  the  second  instar,  2  days  for  the  third  instar, 
and  2  days  for  the  fourth  instar.  The  length  of  time  which  elapsed 
between  the  birth  of  viviparous  females  and  the  date  of  birth  of  the 
first  young  varied  according  to  the  time  of  year  in  which  they  ap- 
peared and  is  presented  in  graphical  form.  This  period  ranged 
from  7  days  in  July  and  August  to  20  days  in  late  October  and 
early  November,  with  a  mean  developmental  period  of  10.5  days 
for  all  seasons.  The  average  length  of  the  productive  period  was 
12.6  days.  The  total  number  of  young  produced  by  one  female 
ranged  from,  2  to  105  individuals  with  an  average  of  24.6  young 
per  mother.  The  maximum  number  of  young  borne  by  one  mother 
in  a  single  day  was  13  and  the  average  number  born  to  one  female 
in  a  day  was  2.1  young.  The  total  length  of  life  for  76  females 
averaged  23.3  days. 


APHIS  RUMICIS  53 

Neither  the  records  made  on  generation  experiments  nor  notes 
taken  in  the  field  serve  to  clarify  the  problem  as  to  what  factor 
or  combination  of  factors  actually  induces  the  appearance  of 
winged  forms  although  I  feel  that  the  appearance  of  the  spring 
and  fall  migrants  is  more  or  less  linked  up  in  some  way  with  tem- 
perature conditions.  The  copulation  experiments  between  males 
taken  from  one  host  with  females  from  a  different  host,  while  in- 
conclusive in  themselves,  are  of  interest  and  value  when  correlated 
with  the  results  of  transfers  of  the  viviparous  females.  Oviparae 
from  woody  shrubs,  when  transferred  to  herbaceous  plants,  con- 
tinued to  develop  and  deposit  ova  on  the  latter. 

The  following  parasitic  and  predaceous  enemies  of  Aphis  rumicis 
were  bred :  Asaphes  americana  Gir.,  Lysiphlebus  testaceipes  Cress., 
Pachyneuron  siphonopJiorw  Ashm.,  a  Cynipid,  Aphidencyrtus  sp., 
Bochartia  sp.,  Megilla  maculata  DeG.,  Adalia  bipunctata  Linn., 
Hippodamia  convergens  Guer.,  and  Coccinella  9-notata  Herbst. 

BIBLIOGRAPHY 

(1)  Amyot,  C.  J.  B. 

1847.     Ann.  Soc.  Ent.  Fr.,  2  me.  Series,  V,  478. 

(2)  Buckton,  G.  B. 

1879.     Monograph  of  British  Aphides,  II,  81. 

(3)  Baker,  A.  C.  &  Turner,  W.  F. 

1915.  Proe.  Ent.  Soc.  Wash.,  XVII,  42. 

(4)     

1919.     Journ.  Agr.  Res.,  XVIII,  6,  317. 

(5)  Bethune,  C.  J. 

1909.     Ont.  Dept.  Agr.  Bui.  171,  13. 

(6)     

1917.  Ont.  Dept.  Agr.  Bui.  251,  11. 

(7)  Bonnet,  C. 

1779.     D'Hist.  Nat.,  1,  6. 

(8)  Britton,  W.  E. 

1916.  Conn.  Bpt.  15,  191. 

(9)     

1917.  Conn.  Bpt.  16,  104. 

(10)     

1923.     Conn.  Geol.  &  Nat.  Hist.  Survey,  Bui.  34,  296  (Patch). 

(11)  Cory,  E.  N. 

1918.  Penins.  Hort.  Soc.  Trans.,  31,  75. 

(12)  Crosby,  C.  R.  &  Leonard,  M.  D. 

1918.  Man.  Veg.  Gard.  Ins.,  76. 

(13)  Curtis,  J. 

1860.     Farm  Insects,  355. 

(14)  Das,  Bashambar 

1918.    Aphid,  of  Lahore,  Mem.  Indian  Mus.,VI,203  (vanderGoot). 


54  IOWA  STUDIES  IN  NATURAL  HISTORY 

(15)     Davidson,  J. 

1914.     Ann.  Appl.  Biol.  I,  118. 


1921.     Ann.  Appl.  Biol.,  VIII,  No.  1,  51. 


1921.     Bui.  Ent.  Res.,  XII,  pt.  1,  81. 


1921.     Roy.  Bub.  Soc,  Sci.  Proc,  n.  ser.  16,  Nos.  25-29,  304. 


1921.     Ann.  Appl.  Biol.,  IX,  No.  2,  135. 


(16) 
(17) 
(18) 
(19) 

(20)     

1923.     Ann.  Appl.  Biol.,  X,  No.  1,  35. 

(21)  Davidson,  W.  M. 

1916.     Journ.  Ec.  Ent.,  IX,  454. 

(22)  Davis,  J.  J. 

1911.     Univ.  of  Neb.  Studies,  XI,  No.  3,  18. 

(23)  De  Geer,  Carl. 

1773.     L'Hist.  des.  Ins.  Ill,  58. 

(24)  De  Ong,  E.  R. 

1918.     Univ.  Calif.  Agric.  Exp.  Sta.  Bui.  294,  347. 

(25)  Essig,  E.  O. 

1915.     Calif.  Hort.  Bui.  IV,  No.  4,  Suppl.,  94. 


(26)     

1917.  Univ.  Calif.  Publ.  Ent.,  I,  No.  7,  341. 

(27)  Essig,  E.  O.  &  Kuwana,  S.  I. 

1918.  Proc.  Calif.  Acad.  Sci.,  4th  ser.,  VIII,  73. 

(28)  Fabricius,  J.  C. 

1775.     Syst.  Ent.,  735. 


1776.     Gen.  Ins.,  303. 


1781.     Spec.  Ins.,  II,  390. 


(29) 
(30) 

(31) 

1794.     Ent.  Syst.,  213. 
(32)     Fitch,  Asa. 

1870.     Thirteenth  Rpt.  Nox.  Ins.  N.  Y.  for  1869,  Trans.  N.  Y.  Sta. 
Agr.  Soc,  XXIX,  495. 


(33) 

Manuscript  notes,  Files  Bur.  Ent.,  U.  S.  D.  A. 

(34)  Fletcher,  J. 

1905.     Can.  Exp.  Farms  Bui.  52,  27. 

(35)  Fonscolombe,  B.  de 

1841.     Ann.  Soc.  Ent.  Fr.,  X,  162. 

(36)  Gilbert,  W.  W.  &  Popenoe,  C.  H. 

1919.     U.  S.  D.  A.  Dept.  Cir.  35,  7. 

(37)  Gillette*  C.  P. 

1910.     Journ.  Ec.  Ent.,  Ill,  406. 


APHIS  RUMICIS  55 

(38)  Gillette,  C.  P.  &  Baker,  C.  F. 

1895.    Colo.  Agr.  Exp.  Sta.  Bui.  31,  Tech.  Ser.  1,  121. 

(39)  Girault,  A.  A. 

1916.     Can.  Ent.,  XLVIII,  342. 

(40)  Hausmann,  F. 

1802.     Illig.  Mag.,  I,  439. 

(41)  Haviland,  Maud  D. 

1919.    Proc.  Chambr.  Phil.  Soc,  XIX,  pt.  V.  226. 

(42)  Hunter,  W.  D. 

1901.     la.  Agr.  Exp.  Sta.  Bui.  60,  104. 

(43)  Headlee,  T.  J. 

1919.    N.  J.  Exp.  Sta.  Cir.  107,  7. 

(44)     

1919.    N.  J.  Hort.  Soc.  Proc,  44,  79. 

(45)  Hayhurst,  P. 

1909.    Ann.  Ent.  Soc.  Am.,  II,  11,  97. 

(46)  Kaltenbach,  J.  H. 

1843.     Mon.  der  Fam.  der  Pflanzenlause,  81. 

(47)  Koch,  C.  L. 

1857.     Die  Pflan.  Aphid.,  50. 

(48)  Kirby,  W.  and  Spence,  W. 

1826.     Introd.  Ent.,  I,  175. 

(49)  Linnaeus,  C. 

1746.    Faun.  Suec.,  217. 

(50)     

1758.     Syst.  Nat.  Ed.  X,  451. 

(51)     

1761.    Faun.  Suec.  Ed.  Alt.  Auct.,  259. 

(52)     

1767.     Syst.  Nat.  Ed.  XII,  I,  734. 

(53)  Lefroy,  H.  M.  and  Howlett,  F.  M. 

1909.     Indian  Ins.  Life,  747. 

(54)  Matsumura,  S. 

1918.    Jour.  Coll.  Agr.  Sapporo,  VII,  pt.  6,  357. 

(55)  Mason,  A.  C. 

1922.  Fla.  Ent.,  VI,  No.  2,  25. 

(56)     

1923.  Fla.  Ent.,  VII,  No.  1,  1. 

(57)  Mosley,  O. 

1841.     Gard.  Chron.,  I,  628,  747. 

(58)  Mordwilko,  A. 

1899.     Horse  Buss.  Ent.  Obsch.,  XXXI,  271. 

(59)     

1907.     Biol  Centralb.,  XXVII,  807. 

(60)  Oestlund,  O.  W. 

1887.     Geol.  and  Nat.  Hist.  Surv.  Minn.,  Bui.  4,  61. 

(61)     

1922.     19th  Rpt.  Sta.  Ent.  Minn.,  129. 


56 

IOWA  STUDIES  IN  NATURAL  HIST 

(62) 

Ohlendorf,  W. 

1917.     Ms.  Library  Cornell  Univ. 

(63) 

O'Kane,  W.  C. 

1916.     Injurious  Insects,  201. 

(64) 

Orton,  W.  A.  and  Chittenden,  F.  H. 

1917.     IT.  S.  Farm.  Bui.  856,  29. 

(65) 

Osborn,  H.  and  Sirrine,  F.  A. 

1893.     la.  Agr.  Exp.  Sta.  Bui.  23,  901. 

(66) 

Patch,  Edith  M. 

1912.     Me.  Agr.  Exp.  Sta.  Bui.  202,  177. 

(67) 

1913.     Me.  Agr.  Exp.  Sta.  Bui.  220. 

(68) 

1914.     Me.  Agr.  Exp.  Sta.  Bui.  225. 

(69) 

1917.     Jour.  Ee.  Ent.,  X,  417. 

(70) 

1918.     Me.  Agr.  Exp.  Sta.  Bui.  270. 

(71) 

1919.     Me.  Agr.  Exp.  Sta.  Bui.  282. 

(72) 

Passerini,  J. 

1863.     Aphididse  Italicae,  37. 

(73) 

Riley,  C.  V.  and  Monell,  J. 

1879.     Bui.  U.  S.  Geol.  Surv.,  V,  No.  1. 

(74) 

Sanborn,  C.  E. 

1904.     Kan.  Univ.  Sci.  Bui.  Ill,  47. 

(75) 

Sanderson,  E.  D. 

1908.     U.  S.  Year  Book,  570. 

(76) 

1912.     Insect  Pests,  317. 

(77) 

Schrank,  F. 

1801.     Faun.  Boica,  II,  pt.  1,  111. 

(78) 

Schouteden,  H. 

1906.     Mem.  de  la  Soe.  Ent.  de  Belg.,  XII,  226. 

(79) 

Scopoli,  J.  A. 

1763.     Ent.  Cam.,  136. 

(80) 

Siebke,  H. 

1874.     Enum.  Ins.  Norveg.,  46. 

(81) 

Smith,  L.  B. 

1917.     Va.  Truck  Sta.  Bui.  23,  504. 

(82) 

Stephens,  J.  F. 

1829.     Syst.  Cat.  Brit.  Ins.  365. 

(83) 

Stewart,  George 

1919.     Utah  Agr.  Coll.  Cir.  37,  38. 

(84) 

Swain,  A.  F. 

1919.     Univ.  Calif.  Publ.  Ent.,  Ill,  1,  101. 

(85) 

Takahashi,  B. 

1921.     Aphid,  of  Formosa,  pt.  I,  47. 

APHIS  RUMICIS  57 


(86)  Talbert,  T.  J. 

1917.     Mo.  Ext.  Cir.  15,  8. 

(87)  Theobald,  F.  V. 

1911.     The  Entomologist,  XLIV,  19. 


1912.     Jour.  Bd.  Agr.,  XIX,  466. 


1912.     Jour.  Econ.  Biol.,  VII,  94. 


1914.     Bui.  Ent.  Res.,  IV,  329. 


1916.     Can.  Ent.,  XL VIII,  234. 


(89) 

(90) 

(91) 

(92) 

1923.     Bui.  Soc.  Roy.  Ent.  D'Egypte,  1922,  47. 

(93)  Thomas,  C. 

1879.     8th  Rpt.  111.  Sta.  Ent.,  88. 

(94)  Uichanco,  L.  B. 

1921.     Psyche,  XXVIII,  95. 

(95)  Van  der  Goot,  P. 

1915.     Kennt.  Holland  BlattL,  220. 

(96)  Wadley,  F.  M. 

1923.     Ann.  Ent.  Soe.  Am.,  XVI,  4,  279. 

(97)  Walker,  F. 

1850.     Ann.  and  Mag.  of  Nat.  Hist.,  V,  Ser.  2,  17. 


(98) 

1852.     Cat.  Homop.  Brit.  Mus.,  IV,  981. 
(99)     Wilson,  H.  F.  and  Vickery,  R.  A. 

1918.     Trans.  Wis.  Ac?td.  Sci.,  XIX,  150. 


PLATE  I 

Fig.  A.     Line   of   first-born   generations,   Aphis  rumicis,   Bustleton   Pa.,   1923. 

Fig.  B.     Relation  between  the  mean  temperature  and  the  developmental  period 
of  viviparous  females  of  succeeding  generations. 


PLATE  I 


Gen. 

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GENERATIONS 


-PEV.PER10P  EACH  GEM 
MEAN  PEV-  PERI OP. 


■  MEAN  TEMP.  EACH  GEM 
MEAN  TEMR  FOR  SEASON. 


PLATE  II 

Fig.  A.     Winged  Male,  Aphis  rumicis,  greatly  enlarged;  B,  Antenna  of  same; 
C,  Cornicle;  D,  Cauda;  E,  Hind  Tarsus. 

Fig.  F.     Winged    Viviparous    Female,    Aphis    rumicis,    greatly    enlarged;    H, 
Cornicle;   I,  Cauda;   J,  Hind  Tarsus. 


PLATE  II 


<  • ,-. . 


PLATE  III 

Fig.  A.  Intermediate  Male,  Aphis  rumicis,  greatly  enlarged.  Only  traces  of 
winged  characters  present  are  tiny  buds  and  a  slight  sign  of 
division  into  thoracic  lobes. 

Fig.  B.  Apterous  Viviparous  Female,  Aphis  rumicis,  greatly  enlarged;  C, 
Antenna  of  same;  D,  Cauda;  E,  Cornicle;  F,  Hind  Tarsus. 


PLATE  III 


PLATE  IV 

Figs.  A,  B,  C.     Antenna!   segment   III   of  winged   males   from   Chenopodium 
album  showing  variation  in  number  and  arrangement  of  sensoria. 

Fig.  J).     Antennal  segment  III  of  spring  migrant  from  Eumcx  erispvs. 

Fig.  E.     Antennal  segment  III  of  fall  migrant  from  Mumex  crispus. 

Fig.  F.     Pupa,  Aphis  rumicis,  greatly  enlarged.     Note  the  white  pulverulent 
patches  on  the  abdomen. 

Fig.  G.     First  Instar  Larva,  Aphis  rumicis,  greatly  enlarged. 


PLATE  IV 


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O 


O 


'0 


PLATE  V 

Fig.  A.  Intermediate  Male,  Aphis  rumicis.  Wings  represented  by  conspicuous 
pads. 

Fig.  B.  Oviparous  Female,  Aphis  rumicis.  Note  swollen  hind  tibiae.  C, 
Cornicle  of  same;  D,  Cauda;  E,  Hind  Tarsus;  F,  Antenna. 

Fig.  G.  Intermediate.  A  viviparous  female  with  characters  of  winged  form 
represented  in  thoracic  characters,  wing  pads,  and  markings  on 
abdomen. 

Fig.  H.  Intermediate.  Oviparous  female  with  eggs  present  in  abdomen. 
The  specimen  has  the  slender  hind  tibiae  characteristic  of  the  vivi- 
parous female. 

Fig.  I.  Stem  Mother,  Aphis  mmicis;  J,  Cornicle  of  same;  K,  Cauda;  L, 
Hind  Tarsus;  M,  Antenna. 


PLATE  V 


PLATE  VI 

Leaves  of  Tropceolum  minus  infested  with  colony  of  Aphis  rumicis.     Note  the 
pupae  with  white  pulverulent  spots  on  abdomen. 


PLATE  VI 


PLATE  VII 

Plants  of  Arctium  lappa  infested  with  colony  of  Aphis  rumicis. 


PLATE  VII 


.y^h- 


PLATE  VIII 

Tig.  A.     Eggs  of  Aphis   rumicis  on  stem  of  Chenopodium  album.     The  stem 
was  broken  and  healed  during  the  growing  period. 

Fig.  B.     Colony  of  Aphis  rumicis  on  stem  of  Chenopodium  album. 

Fig.  C.     Colony  of  Aphis  rumicis  on  the  flower-stems  of  Dahlia   attended  by 
ants. 


PLATE  VIII 


OF*' 


PLATE  IX 

Fig.  A.     Type  of  insect  cages  used  in  the  field  for  rearing  Aphis  rumicis. 

Fig.  B.     Insectary  used  for  life  history  experiments. 


PLATE  IX 


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UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henet  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  3 

THE  DEVELOPMENT  OF  THE  RENAL 

PORTAL  SYSTEM  IN  CHRYSEMYS 

MARGINATA  BELLI  (GRAY) 

by 
Willis  De  Ryke,  Ph.D. 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


THE  DEVELOPMENT  OF  THE  RENAL  PORTAL 

SYSTEM  IN  CHRYSEMYS  MARGINATA 

BELLI  (GRAY) 

I.     INTRODUCTION 
1.    Purpose  and  Scope 

During  the  progress  of  evolution  among  the  vertebrates,  for  some 
unknown  reason  the  renal  portal  system  has  been  discarded.  We 
find  it  present  in  a  typical  form  in  fishes,  Amphibia,  snakes,  lizards 
and  possibly  some  Chelonia.  In  birds  it  is  considerably  modified, 
if  present  at  all,  and  is  apparently  entirely  absent  in  mammals. 
Whatever  may  have  been  the  advantage  or  disadvantage  of  the 
renal  portal  system,  the  change  has  been  made  and  doubtless  the 
transition  lies  somewhere  in  the  Eeptilia,  probably  the  Chelonia. 
Its  presence  in  a  typical  form  in  turtles  has  been  doubted  although 
many  eminent  workers  in  the  fields  of  comparative  anatomy  and 
embryology  have  strongly  suspected  that  the  adult  Chelonia,  or 
at  least  some  species  of  them,  possess  a  true  renal  portal  system. 

The  study  of  the  veins  associated  with  the  kidneys  of  the  turtle 
Chrysemys  marginata  belli  (Gray)  and  their  development  was  un- 
dertaken to  ascertain  the  presence  or  absence  of  a  renal  portal  sys- 
tem in  the  adult  of  this  species,  to  trace  its  development  if  present 
and  the  development  of  certain  veins  closely  related  to  the  kidneys 
and  which  would  probably  be  involved  in  the  embryological  forma- 
tion of  such  a  system.  It  was  also  desirable  to  compare  to  some 
extent  the  development  in  this  form  with  that  of  certain  other  re- 
lated forms. 

The  solution  to  the  problem  of  presence  or  absence  of  the  renal 
portal  system  in  the  adult  lay  in  the  study  of  the  adult  system  of 
veins  related  to  the  kidney  and  a  determination  of  the  presence  or 
absence  of  a  capillary  network  within  the  adult  kidney  which  per- 
mits the  passage  of  blood  on  its  way  from  the  body  capillaries  to 
the  heart. 

The  embryological  study  involved  the  development  of  the  verte- 
bral veins,  posterior  cardinals,  renal  advehens  anterior,  renal  ad- 
vehens  posterior,  subcardinals,  extreme  posterior  region  of  the  post- 
cava  and  the  venous  network  of  the  kidney. 


4  IOWA  STUDIES  IN  NATUEAL  HISTORY 

I  wish  here  to  acknowledge  my  indebtedness  and  express  my 
thanks  to  Dr.  Frank  A.  Stromsten  for  his  constant  assistance,  ad- 
vice, and  criticism  and  to  Prof.  Gilbert  L.  Houser  for  his  many 
helpful  suggestions  and  provision  of  adequate  laboratory  facili- 
ties to  carry  on  this  work. 

2.    Historical 

A  comparatively  small  amount  of  work  has  been  done  in  tracing 
the  detailed  development  of  the  venous  system  of  the  turtle.  It  is 
especially  striking  that  such  an  important  and  interesting  question 
as  the  presence  or  absence  of  a  renal  portal  system  and  its  de- 
velopment as  found  in  Chelonia  should  have  remained  uninvesti- 
gated. The  most  noteworthy  attempts  by  the  early  workers  to 
trace  the  development  of  the  venous  system  of  Chelonia  were  those 
by  Agassiz,  ('57)  and  Eathke,  ('48).  Perhaps  the  reason  for  these 
early  workers  not  having  investigated  this  system  is  due  to  the 
scarcity  of  material  or  what  is  more  probable,  the  lack  of  the  mod- 
ern methods  of  technique. 

A  much  greater  amount  of  work  has  been  done  on  the  develop- 
ment of  the  venous  systems  of  Selachians,  Amphibians,  snakes  and 
lizards.  For  these  extensive  contributions  we  are  indebted  to 
Goette,  Hochstetter,  Hoffmann  and  Eathke.  The  condition  as 
found  in  cyclostomes  has  been  described  by  Eathke,  Eetzius  and 
Johannes  Muller.  The  presence  of  a  renal  portal  system  in  fishes 
was  first  discovered  by  Jacobsen,  one  of  the  pioneer  investigators. 
He  found  various  expressions  of  the  renal  portal  system  which  he 
could  classify  into  three  forms  as  follows:  (1)  The  veins  of  the 
skin  and  body  region  discharge  into  the  kidney  while  the  caudal 
vein  does  not  branch  into  the  kidney  but  discharges  into  the  right 
cardinal  vein.  (2)  Similar  to  the  first  except  that  the  caudal 
vein  branches  in  the  kidney.  (3)  A  modification  of  the  former 
two  in  that  the  caudal  vein  or  another  vein  unites  with  the  portal 
vein  of  the  liver.  Hyrtl  recorded  the  condition  as  found  in  bony 
fishes  and  especially  that  of  Lepidosiren  paradoxa. 

The  principal  work  on  the  development  of  the  veins  in  Selachians 
has  been  done  by  Balfour,  Hochstetter  and  Hoffmann.  Hoffmann 
in  his  work  "Zur  Entwicklungsgeschichte  des  Venensystems  bei  den 
Selaehiern"  gives  an  account  of  the  development  of  the  vena? 
omphalo-mesentericag,  vena  subintestinalis  and  venae  cardinales. 
He  finds  that  the  beginnings  of  the  posterior  cardinal  veins  are 
closely  bound  to  the  anlage  of  the  mesonephros  and  in  early  stages 


EENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  5 

are  comparatively  free  from  anastomoses  with  each  other  but  later 
freely  anastomose.  In  an  embryo  of  20  mm.  the  posterior  cardinals 
have  already  formed  and  begun  to  anastomose  with  the  vena  sub- 
intestinalis  caudalis  producing  a  renal  portal  system.  Balfour 
records  the  vena  subintestinalis  as  appearing  ventral  to  the  ali- 
mentary tract,  being  the  first  large  venous  trunk  to  form  in  Sela- 
chian embryos  and  terminating  shortly  before  the  end  of  the  tail. 
It  bifurcates  at  the  cloaca,  uniting  again  anteriorly.  The  anterior 
part  then  atrophies,  the  posterior  part  remaining  and  becoming  the 
caudal  vein.  As  soon  as  the  cardinal  veins  appear  the  caudal  vein 
unites  with  them.  This  is  accomplished  by  the  degeneration  of  the 
anterior  portion  of  the  anal  ring  and  the  union  of  the  two  posterior 
portions  with  the  posterior  cardinal  veins  on  either  side.  The  anas- 
tomosing branches  between  the  caudal  vein  and  the  posterior  cardi- 
nal veins  pass  through  the  mesonephros  and  eventually  break  up 
into  a  capillary  network  and  a  renal  portal  system  is  established. 
According  to  Hochstetter  the  development  of  the  renal  portal  sys- 
tem in  Selachians  is  as  described  by  Balfour. 

The  development  of  the  renal  portal  system  in  an  Amphibian 
has  been  traced  by  Goette  in  Bombinator  igneus.  According  to  his 
description  the  posterior  cardinal  veins  which  open  anteriorly  into 
the  duct  of  Cuvier  unite  posteriorly  with  the  caudal  vein.  At  this 
union  the  iliac  veins  join  the  system.  In  the  meantime  the  mesone- 
phros has  developed  in  the  region  of  the  union.  The  cardinal  veins 
fuse  close  to  the  mesonephros  and  the  posterior  portion  forms  a 
part  of  the  postcava.  The  anterior  part  of  the  postcava  develops 
independently.  This  is  followed  by  the  atrophy  of  the  anterior 
region  of  the  mesonephros  and  the  posterior  cardinals.  The  veins 
which  first  opened  into  the  posterior  cardinals  now  lose  their  con- 
nections and  form  the  renal  advehentes.  The  iliac  veins  become 
connected  with  a  newly  developed  vein,  the  abdominal,  and  in  this 
manner  have  connection  with  the  postcava  through  Jaeobsen's  vein 
and  with  the  anterior  abdominal  vein  through  the  epigastric  vein. 
In  this  manner  a  renal  portal  system  is  laid  down. 

Probably  the  most  valuable  work  touching  on  the  renal  portal 
system  of  reptiles  has  been  done  by  Bojanus,  Jourdain,  Nicolai, 
Hochstetter,  Hoffmann,  Rathke  and  Stromsten. 

Jourdain  ('59)  in  describing  the  renal  portal  system  of  the 
kidney  of  an  adult  Ophidian  details  its  arrangement  as  follows. 
After  picking  up  the  important  vessels,  mesenteric  vein  and  cloacal 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

veins  as  well  as  a  vein  from  the  tail,  the  renal  portal  vein  proceeds, 
accompanied  mediad  by  the  ureter  and  laterad  by  the  vas  deferens 
or  oviduct,  in  a  circuitous  manner  over  the  kidney.  In  its  course 
it  picks  up  small  veins  from  the  ureter  and  vas  deferens  (oviduct), 
a  vein  parietalis  anterior  and  a  varying  number  of  intercostal- 
spinalis  veins.  Each  of  these  veins  runs  along  the  edge  of  the  kid- 
ney accompanied  by  the  ureter  which  is  on  the  inside.  Their 
branches  are  numerous  and  disappear  for  the  most  part  in  the 
notches  between  the  small  lobes  branching  out  like  dendrites  be- 
tween the  canals  of  the  kidney.  The  advehent  veins  of  the  kidney 
branch  and  become  smaller  and  smaller  until  they  finally  lose 
themselves  in  the  forward  part  of  the  kidney.  From  the  anasto- 
mosis of  the  efferent  veins,  a  system,  the  renal  revehent  arises  which 
courses  anteriorly  from  the  kidney  along  with  the  one  from  the 
opposite  side  and  unites  with  the  postcava. 

Rathke  contributed  to  our  knowledge  of  the  venous  system  of 
Tropidonotus  natrix  ('39),  the  crocodile  ('66)  and  the  turtle  ('48). 
His  account  of  the  development  of  the  venous  system  of  the  natter 
contains  a  very  good  description  of  the  posterior  venous  system  de- 
velopment, a  resume  of  which  follows.  In  the  development  of  the 
natter  the  caudal  vein  is  divided  early  and  each  branch  unites  with 
the  posterior  cardinal.  The  postcava  is  developed  as  a  branch  of 
the  common  stem  of  the  right  omphalomesenteric  vein  and  the 
right  vertebral  vein  lying  in  the  caval  mesentery  and  proceeding 
along  the  dorsal  wall  on  the  median  side  of  the  mesonephros.  The 
mesonephroi  then  begin  to  separate  from  the  body  wall  and  de- 
generate from  anterior  to  posterior.  This  results  in  the  formation 
of  the  vertebral  veins  which  are  formed  from  the  anastomoses  be- 
tween the  segmental  veins  on  both  sides  of  the  vertebral  columns. 
These  vertebral  veins  later  atrophy  in  the  posterior  region  and 
practically  disappear  leaving  little  or  no  trace.  With  the  separa- 
tion of  the  mesonephroi  from  the  dorsal  body  wall  they  begin  to 
degenerate,  and  the  cardinal  veins  to  atrophy  anteriorly  losing 
their  connection  with  the  jugulars. 

The  caudal  vein  with  its  two  branches  and  the  posterior  cardinals 
with  their  tributaries  comprise  the  advehent  system.  The  vena 
cava  and  its  two  large  branches  comprise  the  revehent  system. 

Hochstetter  (?93)  studied  the  development  of  several  species  of 
lizards  giving  a  splendid  account  of  the  development  of  Lacerta 
agilis  and  Lacerta  viridis.     According  to  his  observations  on  the 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  7 

development  of  Lacerta  agilis,  in  a  stage  where  the  intestine  is 
closed  to  a  point  where  the  liver  is  well  developed,  the  posterior 
cardinals  are  already  well  developed,  being  clearly  marked 
in  the  posterior  region  of  the  mesonephros  but  broken  up 
into  blood  sinuses  which  lie  between  the  mesonephric  tubules  in  the 
anterior  region.  At  some  points  the  posterior  cardinals  appear  to 
be  ventral,  at  others  lateral  and  in  the  posterior  region  clearly  dor- 
sal to  the  mesonephroi.  These  veins  also  receive  blood  from  the  seg- 
mental veins.  With  the  increase  in  compactness  of  the  mesonephroi 
the  veins  change  their  relations. 

With  the  growth  of  the  tail  region  the  caudal  vein  becomes  of 
importance.  It  enlarges  and  bifurcates  dorsally  and  anteriorly  to 
the  blind  end  of  the  intestine,  the  two  branches  running  along  the 
median  sides  of  the  mesonephroi.  These  two  veins  anastomose  with 
each  other  anterior  to  the  omphalo-mesenteric  artery  and  connect 
freely  with  the  venous  network  of  the  mesonephroi. 

With  the  formation  of  the  postcava  by  the  union  of  the  omphalo- 
mesenteric veins  with  the  unpaired  portion  of  these  veins  the 
branches  of  the  caudal  vein  lose  their  connections  and  unite  with 
the  posterior  cardinals.  A  degeneration  of  the  anterior  end.  of 
the  mesonephroi  and  the  atrophy  of  the  anterior  portion  of  the 
posterior  cardinals  now  make  the  rest  of  the  posterior  cardinals 
and  the  caudal  vein  and  its  branches  the  afferent  veins  of  the 
mesonephroi. 

The  mesonephroi  now  begin  to  separate  anteriorly  from  the  dor- 
sal body  wall.  This  process  continues  posteriorly.  The  postcava 
bifurcates  and  runs  between  the  mesonephric  bodies  receiving  sev- 
eral branches.  The  postcava  and  its  branches  then  comprise  the 
revehent  system  of  the  mesonephroi. 

While  this  is  taking  place  the  venous  network  of  the  anterior  end 
of  the  mesonephros  becomes  disconnected  from  the  duct  of  Cuvier 
and  becomes  connected  to  a  row  of  segmental,  anastomosing  veins 
which  have  gradually  developed  as  a  result  of  the  separation  of 
the  mesonephroi  from  the  dorsal  body  wall.  The  chains  of  anas- 
tomosing vessels  become  larger  as  the  mesonephroi  degenerate  and 
lie  on  either  side  of  the  vertebral  column  ventral  to  the  rib  anlagen. 
With  the  degeneration  of  the  anterior  portion  of  the  mesonephroi 
the  number  of  connecting  veins  decreases  until  only  a  few  of  them 
at  the  posterior  end  of  the  mesonephroi  remain.  The  chains  of 
veins  form  longitudinal  anastomoses  and  also  anastomose  with  each 
other. 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  embryologieal  development  in  the  other  forms,  including 
Lacerta  viridis  on  which  Jourdain  had  worked,  was  found  in  gen- 
eral to  parallel  that  of  Lacerta  agilis,  the  difference  being  in  min- 
ute details  of  development. 

The  latest  work  of  consequence  on  the  development  of  the  pos- 
terior portion  of  the  venous  system  of  a  reptile  is  that  of  Stromsten 
('05).  He  traced  the  development  of  the  veins  in  the  posterior 
region  of  the  turtle  Kinosternon  pennsylvanicum.  His  studies  in- 
cluded the  development  of  the  hepatic  portal  system  and  to  a  con- 
siderable extent  the  development  of  the  umbilicals,  abdominals  and 
the  larger  veins  involved  in  the  development  of  the  renal  portal 
system. 

According  to  Stromsten,  the  posterior  cardinals  and  subcardinals 
are  already  formed  in  the  youngest  embryo  studied,  an  embryo  of 
7.4  mm.  crown  rump  measurement.  The  posterior  cardinals  extend 
from  the  caudal  termination  of  the  mesonephric  ducts  along  the 
entire  length  of  the  mesonephroi.  At  the  caudal  termination  of 
the  mesonephric  ducts  the  posterior  cardinals  receive  a  number  of 
small  branches  from  the  tail  region,  the  last  dorsal  intersegmental 
branch  and  a  stout  anastomosing  branch  from  the  subcardinal  of 
the  same  side.  The  portion  of  the  posterior  cardinals  between  the 
cranial  end  of  the  mesonephros  and  the  sinus  venosus  is  broken  up 
into  two  or  three  vessels. 

In  a  7.4  mm.  embryo  the  subcardinals  are  formed  and  connect 
with  the  posterior  cardinals  by  numerous  anastomoses  but  do  not 
connect  with  each  other.  With  growth  the  two  branches  of  the 
caudal  vein  unite  with  the  subcardinal  veins,  establishing  a  renal 
portal  system.  With  continued  development,  the  forking  caudal 
vein  loses  its  connection  with  the  subcardinals  and  unites  with  the 
posterior  cardinals.  The  postcava  develops  and  the  course  of  the 
blood  is  reversed  in  the  portal  system  of  the  mesonephroi. 

The  posterior  vertebral  veins  are  fused  dorso-segmental  branches 
of  the  posterior  cardinals  and  lie  dorsal  to  the  rib  anlage. 

The  anterior  and  posterior  renal  advehent  veins  of  the  kidneys 
represent  the  remains  of  the  posterior  cardinals. 

3.     Material  and  Methods 
Adults 
Ample  material  for  the  study  of  this  problem  was  found  in  the 
region  of  Lake  Okoboji  located  in  the  northwestern  part  of  the 
State  of  Iowa.    I  was  quite  fortunate  to  find  that  a  laying  ground 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  9 

for  Chrysemys  marginata  belli  (Gray)  was  conveniently  adjacent 
to  the  grounds  of  the  Lakeside  Laboratory  on  Miller's  Bay.  The 
turtles  swarmed  up  the  sloping  gravel  bank  usually  between  the 
hours  of  four  to  eight  of  an  evening  to  lay  their  eggs,  making  a 
splendid  opportunity  for  observations,  recording  the  time  of  lay- 
ing and  marking  the  nests. 

Before  proceeding  with  the  study  of  the  embryonic  changes  in- 
volved in  the  developing  venous  system  the  adult  venous  systems 
of  about  twenty-five  turtles  were  studied,  special  attention  being 
given  to  the  veins  related  to  the  kidneys.  That  the  blood  vessels 
might  be  in  as  expanded  condition  as  possible  and  better  injections 
assured  the  animals  were  killed  with  a  concentrated  solution  of 
chloral  hydrate. 

The  injection  media  used  most  successfully  were  a  yellow  starch 
paste  mass  and  a  colored  gelatin  mass.  The  yellow  starch  mass  was 
prepared  according  to  Guyer.1  A  carmine  gelatin  injection  mass 
was  prepared  according  to  Walker's  variation  as  given  by  Guyer,2 
and  also  a  blue  gelatin  injection  mass  as  given  by  Guyer.3  The 
setting  of  the  gelatin  during  the  process  of  injection  was  prevented 
by  adding  a  small  amount  of  potassium  iodide.  The  injection 
masses  were  forced  into  the  vessels  by  means  of  a  metal  syringe 
or  by  the  gravity  method,  both  of  which  were  quite  adequate.  Im- 
mediately after  injection  the  specimens  were  plunged  into  a  ten 
per  cent  formalin  solution,  thus  coagulating  the  gelatin. 

The  necessity  for  determining  the  arrangement  of  the  veins 
within  the  kidney  is  quite  obvious.  The  small  size  of  the  veins 
entering  or  leaving  the  kidney  makes  it  impossible  to  remove  the 
kidney  and  inject.  For  this  reason  it  was  necessary  to  inject  a  large 
portion  of  the  venous  system  at  sufficiently  high  pressure  to  guar- 
antee the  filling  of  the  vessels  of  the  kidney. 

Injections  of  yellow  starch  paste  were  made  and  dissection  car- 
ried out  as  far  as  possible  under  the  binocular  microscope.  This 
method  however  had  its  limits  in  that  the  relations  of  the  smaller 
and  more  numerous  vessels  were  lost  through  the  necessary  destruc- 
tion of  some  of  them  during  dissection. 

In  order  to  preserve  these  smaller  vessels  a  less  mechanical  method 
was  sought.     The  first  attempts  were  by  means  of  an  injection  of 


*Guyer — Animal  Micrology,  p.  92. 
2Guyer — Animal  Micrology,  p.  83. 
3Guyer — Animal  Micrology,  p.  84. 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

ozokerite  wax.  The  greatest  difficulty  encountered  here  was  that 
a  temperature  sufficiently  high  to  keep  the  wax  in  a  liquid  con- 
dition had  to  be  maintained.  The  metal  syringe,  the  wax,  and  the 
specimen  had  to  be  at  this  temperature  to  prevent  the  hardening 
before  complete  injection.  This  difficulty  was  overcome  by  placing 
the  specimen  and  apparatus  in  water  at  the  temperature  of  the  melt- 
ing point  of  the  wax.  With  rapid  operation  the  injection  could  be 
made  but  by  no  means  was  success  achieved  at  all  trials. 

These  injected  specimens  were  then  cooled  and  the  kidneys  with 
their  projecting  blood  vessels  removed  from  the  turtle.  Some  of 
them  were  then  placed  in  artificial  gastric  juice  and  kept  in  an  in- 
cubator until  the  digestion  of  the  tissue  was  complete.  Another 
method  used  for  eliminating  the  tissue  was  that  of  corrosion  to  be 
discussed  presently.  Wax  casts  resulted  which  were  very  good 
for  study  but  the  difficulty  of  their  preservation  and  their  delicacy 
made  it  desirable  to  have  a  method  whereby  permanency  might  be 
gained. 

In  seeking  a  permanent  injection  mass  celloidin  was  tried  and 
found  to  be  a  fairly  successful  method  but  somewhat  expensive  as 
many  failures  of  injection  were  unavoidable. 

The  method  finally  adopted  and  the  most  successful  one  was  that 
of  injecting  a  colored  liquid  celluloid.  This  injection  fluid  is  pre- 
pared as  follows.  Sheet  celluloid  secured  from  discarded  automo- 
bile curtains  is  thoroughly  washed  and  cut  into  small  pieces.  About 
twenty  grams  of  this  is  dissolved  in  100  cc.  of  acetone  and  allowed 
to  stand  for  twTenty-four  hours.  Fifteen  grams  of  camphor  is  then 
dissolved  in  this  solution.  This  is  then  used  as  a  stock  solution  and 
must  be  kept  air  tight.  Before  using  this  liquid  as  an  injection 
medium  it  is  thinned  by  the  addition  of  acetone  carrying  a  coloring 
agent.  The  size  of  the  vessels  to  be  injected  determines  the  viscosity 
of  the  injection  medium  to  be  employed.  The  liquid  was  thinned 
to  almost  a  watery  viscosity  when  it  was  desired  to  inject  capillaries. 
A  large  number  of  coloring  agents  were  tried,  the  most  satisfactory 
of  which  were  found  to  be  crystal  violet,  brilliant  green  and  alkanet, 
all  soluble  in  acetone. 

This  injection  fluid  on  coming  in  contact  with  water  forms  a 
hard  east  and  does  not  readily  break.  With  an  increase  in  the  per- 
centage of  camphor  it  may  be  made  to  take  on  the  nature  of  rub- 
ber. This  medium  then  produced  the  desirable  characteristics  since 
it  is  not  brittle  and  stands  considerable  rough  handling. 


EBNAL  PORTAL  SYSTEM  IN  CHKYSEMYS  11 

The  turtles  were  killed  by  chloral  hydrate  and  the  plastron  care- 
fully removed.  Injection  was  then  made  through  the  left  abdomi- 
nal vein  after  tying  off  the  right,  through  the  postcava,  or  through 
the  left  aortic  arch  after  tying  off  the  right.  Not  only  single  in- 
jections were  carried  out  but  double  and  triple  injections  of  the 
colors  were  resorted  to  in  all  possible  combinations. 

After  injection  the  specimens  were  immediately  placed  in  cold 
water  where  they  remained  for  twelve  hours.  This  permitted  the 
casts  to  become  hard.  The  kidneys  were  then  carefully  removed 
with  their  protruding  injected  vessels  and  placed  in  artificial  gas- 
tric or  pancreatic  juice  in  a  suitable  warming  oven,  or  more  com- 
monly and  with  equal  success  they  were  subjected  to  the  action  of 
concentrated  muriatic  acid  for  twelve  to  eighteen  hours.  It  was 
then  possible  to  wash  out  in  water  the  corroded  tissue.  This  was 
accomplished  by  admitting  a  gentle  flow  down  a  stirring  rod  from 
an  open  tap  or  by  carefully  using  a  pipette,  both  of  which  methods 
proved  satisfactory.  For  the  extremely  fine  structure  this  method 
was  slightly  altered.  After  a  large  portion  of  the  kidney  substance 
had  been  corroded  and  washed  out  the  kidneys  were  permitted  to 
remain  in  the  water  for  days  until  disintegration  had  taken  place 
and  the  tissue  practically  removed  itself  from  the  meshwork  of 
minute  blood  vessels.  This  method  produced  very  beautiful  casts, 
accurate  to  the  minutest  detail  and  of  such  a  permanent  nature  that 
they  could  be  studied  without  damage  to  them. 

In  addition  to  the  study  of  the  casts,  the  finer  vascular  structure 
of  the  kidney  was  studied  by  means  of  serial  sections.  These  serial 
sections  were  made  of  the  kidneys  of  fifteen  specimens  which  had 
been  injected  under  high  pressure  with  a  carmine  gelatin  mass  or 
an  aqueous  solution  of  Berlin  blue.  Also  a  specimen  just  hatched 
was  serially  sectioned  in  the  region  of  the  kidneys,  stained  in  borax 
carmine  and  mounted  for  study. 

Embryos 

Two  entire  summers  were  given  over  chiefly  to  securing  material 
for  the  embryological  study.  No  difficulty  was  encountered  in 
locating  the  nests  or  securing  eggs.  The  laying  season  was  found 
to  extend  from  the  middle  of  June  to  about  the  twenty-fifth  of 
July.  The  laying  usually  takes  place  between  the  hours  of  four 
to  eight  in  the  afternoon,  the  number  of  eggs  in  a  clutch  varying 
from  five  to  fifteen  and  averaging  about  eleven. 

During  the  summer  of  1923  ninety-six  nests  of  the  painted  turtle 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

Chrysemys  marginal  a  belli  were  located  and  during  the  summer 
of  1924  about  fifty  nests  of  the  same  species  were  located.  From 
these  eggs  I  was  able  to  secure  about  twelve  hundred  embryos. 

The  desire  for  embryos  of  as  many  gradations  in  size  as  possible 
led  to  two  plans  for  securing  them.  The  first  was  to  stake  and 
record  the  nest  at  the  time  of  laying  and  remove  the  entire  clutch 
when  embryos  of  this  particular  age  were  desired.  The  second  was 
to  stake  nests  through  fifteen  successive  days  of  laying  and  remove 
two  or  three  eggs  from  each  nest  every  fifteen  days.  However  no 
exact  method  for  securing  a  graded  series  is  possible  owing  to  the 
fact  that  different  conditions  such  as  kind  of  soil,  depth  eggs  were 
laid,  amount  of  sunshine  and  shade  alter  the  incubation  period. 
Not  only  is  this  true  of  each  nest  but  it  is  true  of  each  egg  in  the 
nest,  so  it  is  possible  to  find  a  single  clutch  having  embryos  at 
various  stages  of  development.  Three  pairs  of  twins  were  found 
during  this  period  and  it  was  quite  interesting  to  find  in  each 
case  that  one  of  the  twins  had  outgrown  the  other  and  in  one  ease 
the  larger  was  at  least  twelve  times  the  size  of  the  smaller. 

The  small  embryos  adhere  closely  to  the  shell  making  their  re- 
moval somewhat  difficult.  It  was  found  much  more  expedient  to 
locate  the  minute  embryo  with  a  hand  lens  and  cut  around  it 
through  the  shell,  placing  the  entire  piece,  shell  and  embryo,  in  the 
fixing  fluid.  The  embryo  could  then  be  easily  separated  from  the 
shell  after  reaching  the  alcohols.  The  larger  embryos  could  of 
course  be  easily  removed  from  the  shell  and  fixed. 

Fixation  wras  made  in  Bouin's  picro-formol  fluid  or  in  chrom- 
aceto-formalin  mixture.  The  length  of  time  of  fixation  ranged 
from  one  hour  to  four  hours,  depending  upon  the  size  of  the 
embryos.  Just  before  using,  two  volumes  of  this  mixture  are  added 
to  one  volume  of  formalin. 

BOUIN'S  PICRO-FORMOL 

Picric  acid,   saturated   aqueous   solution 75  parts 

Formalin    25  parts 

Acetic  acid  (glacial)   5  parts 

CHROM-ACETO-FORMALIN  MIXTURE 

Chromic   acid,    1   per   cent   solution 16  parts 

Glacial  acetic  acid  1  part 

These  two  fixing  fluids  were  found  to  have  a  double  advantage. 
They  were  excellent  in  fixing  the  tissues  and  in  addition,  the  glacial 
acetic  acid  attacked  and  destroyed  the  greater  part  of  the  eggshell. 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  13 

The  embryos  were  then  passed  through  the  graded  alcohols  until 
seventy  per  cent  was  reached  where  they  remained  until  they  could 
be  stained  and  sectioned. 

The  process  of  staining  and  sectioning  was  done  at  the  State 
University  of  Iowa.  A  series  of  embryos  was  selected  for  section- 
ing. Each  embryo  was  drawn  by  the  camera  lucida  and  the  mag- 
nification recorded  in  order  that  reference  might  be  obtained  and 
measurements  made.  Some  of  the  embryos  were  then  stained  in 
toto  with  borax  carmine,  passed  through  the  graded  alcohols,  cleared 
in  xylol,  embedded  in  paraffin,  sectioned  and  mounted.  The  ma- 
jority of  the  embryos  were  passed  through  the  graded  alcohols, 
cleared  in  xylol,  embedded  in  paraffin,  sectioned,  mounted,  stained 
in  Delafield's  hemotoxylin  and  eounterstained  with  Grubler's 
Orange  G.  acidulated  slightly  with  acetic  acid.  In  sectioning  the 
embryos  those  from  1.2  mm.  crown  rump  measurement  to  16  mm. 
crown  rump  measurement  were  cut  20  microns.  Those  from  8  mm. 
to  12  mm.  carapace  length  measurement  were  cut  20  microns.  Those 
from  12  mm.  to  14  mm.  carapace  length  measurement  were  cut  25 
microns  and  one  with  a  22  mm.  carapace  was  cut  50  microns. 

That  the  study  of  the  sections  might  be  supplemented  by  the 
study  of  injected  embryos  approximately  one  hundred  embryos 
ranging  in  size  from  the  earliest  stages  of  development  to  the  adult 
were  injected  with  various  fluids.  The  greatest  difficulty  en- 
countered in  this  technique  was  to  find  an  injection  fluid  whose 
viscosity  was  low  enough  to  permit  the  complete  injection  of  the 
finer  vessels  of  the  embryo  and  still  not  leave  the  vessels  and  pene- 
trate the  tissues.  Certainly  the  most  logical  form  of  an  injection 
fluid  for  this  purpose  would  be  some  colloid  solution  or  perhaps  a 
celluloid  injection.  The  latter  was  tried  numerous  times  and  in 
many  degrees  of  concentration,  but  the  fluid  invariably  hardened 
before  complete  injection  of  the  finer  capillaries.  Considerable 
time  was  spent  in  search  of  a  suitable  colloid  solution.  Among  the 
large  number  tried  it  was  found  the  best  results  could  be  obtained 
by  using  Higgin's  Black  India  Ink,  an  aqueous  solution  of  Berlin 
blue  or  alkanet. 

After  several  mechanical  devices  for  injection  of  the  embryos  had 
been  tried,  it  was  found  that  the  simplest  type  was  the  most  suc- 
cessful. This  consisted  of  a  small  rubber  tube  with  a  mouth-piece 
inserted  at  one  end  and  a  glass  canula  at  the  other.  In  the  con- 
struction of  this  apparatus  there  is  but  one  difficult  feature;  the 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

construction  of  the  canula.  This  is  done  by  drawing  out  a  small 
glass  tube  into  a  hairlike  capillary  three  or  four  inches  long.  By 
placing  this  under  a  microscope  the  point  at  which  the  space  ceases 
and  the  solid  glass  begins  may  be  determined.  With  a  pair  of 
scissors  the  tube  may  be  cut  at  this  point  leaving  a  very  fine  hairlike 
capillary  tube. 

In  using  this  mechanism  the  canula  is  carefully  inserted  in  the 
rubber  tube  and  the  end  dipped  into  the  injecting  fluid.  The  op- 
erator then  with  the  mouthpiece  in  his  mouth  draws  the  fluid  into 
the  canula.  Then  while  looking  through  a  binocular  the  canula  may 
be  inserted  in  the  heart,  the  sinus  marginalis,  the  jugular  vein, 
the  umbilical  vessels  or  any  other  clearly  discernible  vessel.  The 
operator  then  applies  pressure  to  the  fluid,  forcing  it  into  the  vas- 
cular system  of  the  embryo.  The  canula  after  once  being  used  must 
be  kept  in  water  to  prevent  the  closure  of  the  tube. 

From  the  injected  embryos  three  series  were  selected  duplicating 
as  nearly  as  possible  the  series  which  had  been  sectioned.  The  mem- 
bers of  the  first  series  were  serially  cross  sectioned  and  mounted. 
Those  of  the  second  series  were  cut  into  thick  longitudinal  sections 
and  mounted.  The  smaller  members  of  the  third  series  were  used 
in  whole  mounts.  By  this  means  it  was  then  possible  to  obtain  a 
check  on  the  study  of  the  stained  cross  sections. 

II.  ADULT  RENAL  PORTAL  SYSTEM 
The  right  and  left  abdominal  veins  issue  from  the  liver  substance 
and  lie  on  either  side  of  the  ventral  median  line.  They  run  ven- 
trally  for  a  short  distance  but  soon  make  a  sharp  turn  in  a  pos- 
terior direction,  lie  immediately  ventral  to  the  peritoneum  and 
course  toward  the  ventral  median  line.  They  receive  as  tributaries 
during  this  part  of  their  course,  a  small  gastric  vein,  a  vein  from 
the  pectoral  muscles  and  a  small  vein  from  the  tensor-pleuro-peri- 
toneal  muscle.  They  gradually  approach  each  other  in  their  course 
diverging  again  at  a  point  just  anterior  to  the  pubis.  Slightly  pos- 
terior and  ventral  to  this  they  are  placed  in  communication  by  a 
transverse  vessel  lying  ventral  to  the  pubis  and  receiving  branches 
from  the  obturator  externus  and  pubo-plastinalis.  Continuing  pos- 
teriorly and  diverging  they  angle  in  a  dorsal  direction  following 
the  curve  produced  by  the  pelvic  girdle  and  carapace  until  they 
join  the  external  iliac  vein  of  their  respective  sides.  In  the  latter 
part  of  their  course  they  receive  tributaries  from  the  obturator 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  15 

interims  muscle,  a  large  branch  which  anastomoses  with  the  mar- 
gino-costal  vein  of  the  carapace,  a  vein  from  the  pubo-plastinalis 
muscle,  a  branch  from  the  vastus  femoras  rectus  muscle  and  the 
femoral  vein.  The  abdominals  unite  with  the  circumflex  iliac  veins 
of  their  respective  sides  to  form  the  external  iliac  veins. 

The  ischiadic  vein  leaves  the  thigh,  passes  into  the  pelvis  and 
unites  with  the  common  coccygeal  vein  to  form  the  circumflex 
iliac  vein. 

The  circumflex  iliac  vein  courses  dorsally,  receives  the  epigastric 
vein  and  unites  with  the  abdominal  vein  of  its  side  to  form  the  ex- 
ternal iliac  vein. 

The  external  iliac  vein  makes  a  sharp  turn  and  courses  toward 
the  median  line.  Reaching  the  external  border  of  the  kidney  it 
passes  to  the  ventral  surface  where  it  unites  with  the  renal  ad- 
vehentes. 

The  posterior  renal  advehent  vein  is  formed  by  the  union  of  a 
number  of  small  branches  bringing  blood  from  the  muscles  of  the 
pelvis,  the  caudal  region  and  cloaca  with  its  closely  related  organs. 
This  vein  then  passes  dorsally  and  anteriorly  within  the  pelvis. 
Leaving  the  pelvis  and  reaching  the  posterior  edge  of  the  kidney 
it  passes  over  and  in  close  contact  with  the  ventral  surface  of  the 
kidney  where  it  gives  off  afferent  branches  to  the  kidney  and 
eventually  anastomoses  with  the  anterior  renal  advehent  vein  at  a 
point  where  these  two  unite  with  the  external  iliac  vein. 

The  anterior  renal  advehent  vein,  as  a  branch  of  the  vertebral 
vein  arises  between  the  fifth  and  sixth  ribs,  receives  the  fifth  inter- 
costal vein  and  immediately  passes  to  the  ventro-lateral  surface  of 
the  anterior  portion  of  the  kidney.  As  it  courses  along  the  surface 
of  the  kidney  it  gives  off  afferent  branches  and  unites  posteriorly 
with  the  renal  advehent  vein  at  a  point  where  both  are  joined  by 
the  iliac  vein. 

For  convenience  of  discussion  the  portions  of  the  anterior  and 
posterior  renal  advehent  veins  lying  adjacent  to  the  surface  of  the 
kidneys  will  hereafter  be  spoken  of  as  the  renal  portal  vein. 

The  vertebral  veins  arise  as  a  bifurcation  of  a  single  vein  in  the 
region  of  the  first  thoracic  vertebra  and  run  posteriorly  on  either 
side  of  the  spinal  column.  In  their  course  they  lie  dorsal  to  the 
ribs  and  receive  the  first  four  intercostal  veins  and  veins  from  the 
spinal  cord.  Between  the  fifth  and  sixth  ribs  the  vertebral  vein 
gives  off  a  large  branch,  the  anterior  renal  advehent  vein.     Pos- 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

terior  to  this  branch  they  diminish  considerably  in  size,  give  off 
numerous  small  branches  to  the  kidneys  and  continue  posteriorly 
gradually  becoming  smaller  in  diameter  and  eventually  ending  by 
receiving  a  number  of  minute  branches  from  the  extreme  caudal 
region. 

The  postcava  is  formed  between  the  kidneys  by  the  union  of  two 
short  thick  veins.  These  in  turn  result  from  an  anastomosis  of 
veins  leaving  the  kidney,  the  latter  veins  usually  numbering  three 
from  the  left  kidney  and  two  from  the  right,  but  frequently  the 
reverse  is  true.  The  veins  returning  blood  from  the  ovaries  or 
testes  unite  with  these  veins  in  the  region  of  their  entrance  into 
the  kidney  substance.  The  postcava  leads  anteriorly  coursing  away 
from  the  median  line  toward  the  duodenal  flexure  and  enters  the 
right  dorsal  lobe  of  the  liver.  Posterior  to  the  kidneys  there  is 
no  postcava. 

The  kidneys  are  a  pair  of  lozenge  shaped  organs  lying  in  the 
posterior  dorsal  curvature  of  the  carapace,  one  on  each  side  of  the 
spinal  column.  They  present  three  lobulated  surfaces,  a  curved 
dorsal  surface,  a  mesial  surface  and  a  latero-ventral  surface.  The 
surfaces  are  united  with  each  other  by  rounded  edges  of  consid- 
erable curvature. 

The  venous  tributaries  to  the  postcava  arise  from  the  mesial  ven- 
tral edge  of  each  kidney.  These  tributaries  branch  rapidly  into 
smaller  veins  which  enter  the  kidney  substance  and  embed  them- 
selves between  the  lobules. 

Closely  adhering  to  the  latero-ventral  surface  is  the  renal  portal 
vein  joined  about  midway  by  the  external  iliac  vein  which  is  par- 
tially buried  between  the  kidney  lobules.  On  the  side  in  contact 
with  the  kidney  the  renal  portal  vein  branches  profusely,  the  af- 
ferent vessels  entering  the  Jddney  substance  between  the  lobules. 

In  an  effort  to  determine  the  true  nature  of  the  connections  be- 
tween the  renal  portal  vein  and  the  postcava  a  heavy  yellow  starch 
paste  mass  under  a  constant  pressure  was  injected  into  the  post- 
cava of  a  large  number  of  specimens.  In  no  case  was  I  able  to  get 
the  injection  mass  to  pass  through  the  veins  of  the  kidney  and  ap- 
pear in  the  renal  portal  vein.  In  another  group  of  specimens  the 
injection  was  carried  out  in  the  opposite  direction  by  injecting,  into 
the  left  abdominal  vein  after  tying  off  the  right  and  here  again  I 
was  unable  to  get  the  injection  mass  to  pass  through  the  veins  of 
the  kidnej-  and  enter  the  postcava.     My  results  from  the  yellow 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  17 

starch  paste  injection  agree  with  those  obtained  by  Lewis  ( '16)  and 
disagree  with  those  obtained  by  Robinson  ('18)  both  of  whom  in- 
vestigated the  condition  in  the  adult  of  this  form. 

In  other  specimens  injections  of  a  gelatin  mass  were  carried  out 
in  the  same  manner  as  that  used  with  the  starch  paste.  The  gelatin 
was  colored  with  carmine  or  Berlin  blue.  These  fluids  never  failed 
to  pass  through  the  veins  of  the  kidneys  and  appear  in  the  oppo- 
site vessel. 

The  results  of  these  injections  indicated  that  the  vessels  of  the 
kidney  are  too  small  to  permit  the  passage  of  the  starch  but  that 
vessels  do  connect  the  renal  portal  vein  with  the  postcava  and  that 
they  are  of  capillary  size. 

By  means  of  the  celluloid  corrosion  method  celluloid  casts  were 
made  of  the  vessels  of  the  kidneys.  Some  of  these  were  made  from 
single  injections  while  others  were  made  from  double  injections. 
In  these  injections  a  thin  colored  celluloid  solution  was  used.  In 
the  single  injections  the  fluid  was  injected  into  either  the  renal 
portal  through  the  abdominal  and  external  iliac  or  into  the  post- 
cava. In  either  case,  after  corrosion  or  digestion  there  remained 
a  cast  of  the  vein  with  all  its  branches  ultimately  breaking  up  into 
capillary  vessels,  quite  clearly  demonstrating  that  no  connection 
between  the  postcava  and  renal  portal  vein  existed  other  than  of 
a  capillary  size.  The  double  injections  were  made  by  injecting  two 
colors  of  thin  celluloid,  one  color  through  the  postcava  and  the  other 
through  the  abdominal  and  external  iliac  into  the  renal  portal  vein. 
These  casts  were  then  carefully  examined  and  dissected  beneath  the 
binocular  microscope  and  invariably  I  was  unable  to  find  a  single 
connection  larger  than  capillary  size. 

For  microscopical  examination  of  the  internal  vascular  structure 
a  number  of  kidneys  were  injected  with  carmine  gelatin  through 
the  left  abdominal  vein  and  an  aqueous  solution  of  Berlin  blue 
through  the  aorta.  A  study  of  the  serial  sections  of  these  injected 
specimens  revealed  the  fact  that  no  connections  larger  than  capil- 
laries were  present  between  the  branches  of  the  renal  portal  vein 
and  those  of  the  postcava  but  that  a  capillary  network  with  its 
glomeruli  connections  existed  in  which  the  branches  of  the  post- 
cava and  renal  portal  vein  ended,  thus  making  a  capillary  system 
the  only  passage  for  blood  between  these  two  large  trunks. 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

III.     EMBRYOLOGY 

The  development  of  the  renal  portal  system  has  been  followed 
through  a  series  of  serially  sectioned  embryos  of  Chrysemys  mar- 
ginata  belli  and  this  supplemented  by  a  study  of  injected  embryos 
of  the  same  species.  The  youngest  embryo  of  the  sectioned  series 
measures  1.2  mm.  in  length  and  the  oldest  has  a  carapace  length 
of  22  mm.  The  measurements  of  the  younger  embryos  are  crown 
rump  measurements  while  those  of  the  older  embryos  are  measure- 
ments of  the  length  of  the  carapace.  In  the  present  work  the  meas- 
urements referred  to  will  be  crown  rump  measurements  unless 
carapace  measurement  is  specified. 

The  outlines  as  shown  in  Figs.  1  to  6,  Plate  I,  are  outlines  of  the 
embryos  whose  reconstructed  blood  vessels  are  used  for  explanation 
in  this  work.  The  following  table  indicates  the  outline  drawing, 
the  length  of  the  embryo  and  the  reconstructions  of  its  venous 
system. 

OUTLINE  FIGURE     LENGTH  IN  MM.     RECONSTRUCTION  FIGURES 

1  7  Plate  II 

2  10  Plate  III 

3  13  Plate  IV 

4  8  (carapace)         Plate  Y 

5  12  (carapace)         Plate  YI 

6  22  (carapace)         Plate  YII 

The  posterior  cardinal  veins  first  appear  in  an  embryo  of  4  mm. 
length.  At  this  early  stage  these  vessels  open  into  the  duct  of 
Cuvier,  continue  posteriorly  and  gradually  diminish  in  diameter. 
In  the  anterior  portion  they  lie  lateral  to  the  mesonephric  duct  but 
shortly  swing  to  a  dorso-lateral  position.  At  this  time  there  are 
also  noticeable  disconnected  venous  islands  formed  ventral  and 
mesial  to  the  mesonephric  duct.  These  islands  are  to  be  connected 
in  the  future  to  form  the  subeardinal  veins. 

An  embryo  of  7  mm.  length  (Plate  II)  has  the  posterior  cardinal 
veins  well  developed  anteriorly  but  posteriorly  the  vessels  gradu- 
ally reduce  their  diameter  and  are  entirely  wanting  as  a  continuous 
vein  in  the  extreme  posterior  region  of  the  mesonephroi.  However, 
the  evidence  of  their  future  development  in  this  region  is  indicated 
by  several  blood  sinuses  of  considerable  size.  The  posterior  limb 
bud  has  at  this  time  made  its  appearance,  its  drainage  being  cared 
for  by  the  external  iliac  vein  (V.  E.  I.  D.  and  S.)  which  empties 
its  blood  into  the  posterior  cardinal. 

The  future  vertebral  veins  are  also  foreshadowed  at  this  early 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  19 

period  by  the  development  along  their  future  path  of  a  number  of 
small  blood  sinuses. 

The  subcardinal  veins  follow  rather  closely  the  development  of 
the  posterior  cardinal  veins.  Through  anastomoses  of  the  blood 
sinuses  of  the  preceding  stage  a  pair  of  venous  channels  or  veins 
has  been  established.  These  vessels  lie  on  the  median  ventral  sur- 
face and  in  close  relation  to  the  mesonephroi.  They  eventually 
unite  with  each  other  and  with  the  posterior  cardinal  veins.  Even 
at  this  early  stage  there  has  been  formed  a  few  prominent  unions 
between  the  posterior  cardinals  and  the  subcardinals  (Plate  II, 
Pc.Sc.A.).  Not  only  has  a  connection  been  established  between  the 
larger  portions  of  the  veins,  but  at  least  one  has  been  formed  be- 
tween two  of  the  small  portions  which  are  as  yet  little  more  than 
blood  sinuses.  These  anastomoses  do  not  at  this  time  penetrate  the 
mesonephric  substance  but  lie  close  upon  the  surface  of  that  organ. 

Anteriorly  the  posterior  cardinals  are  beginning  to  show  dorsal 
branches  which  later  pass  dorsal  to  the  rib  anlagen  and  usually  bi- 
furcate at  this  point,  later  becoming  connected  with  each  other 
through  intermediate  blood  sinuses. 

An  embryo  of  10  mm.  length  shows  conditions  as  represented  in 
Plate  III.  With  the  growth  of  the  mesonephroi  the  posterior  cardi- 
nal veins  have  reached  a  stage  of  completeness.  Their  position  is 
dorsal  and  slightly  lateral  to  the  mesonephroi.  The  dorsal  segmen- 
tal branches  of  the  posterior  cardinals  are  fairly  well  established. 
The  blood  sinuses  in  the  path  of  the  future  vertebral  veins  have  by 
this  time  increased  considerably  in  size  and  become  more  numer- 
ous. The  subcardinal  veins  have  rapidly  developed  into  a  pair  of 
definite  blood  vessels  lying  ventral  along  the  mesial  edge  of  the 
mesonephroi,  the  right  subcardinal  vein  being  continued  somewhat 
more  anteriorly  than  the  left. 

A  complete  union  of  the  subcardinal  vessels  has  occurred  just 
posterior  to  the  omphalo-mesenteric  artery  by  three  large  connec- 
tions. There  has  also  developed  a  free  anastomosis  between  the 
posterior  cardinal  and  the  subcardinal  vein  of  its  respective  side. 
These  connections  are  for  the  most  part  situated  on  the  periphery 
of  the  mesonephros,  either  on  the  dorso-median  surface  or  the 
latero-ventral  surface  but  appear  to  be  in  closer  relation  to  the 
mesonephric  tubules  than  in  the  previous  stage.  However,  many 
of  them  do  find  their  way  between  the  tubules  of  that  body. 

At  this  stage  in  the  development  we  find  the  caudal  vein  def i- 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

nitely  laid  down.  It  bifurcates  and  each  branch  unites  with  the 
posterior  portion  of  the  subcardinal  vein  of  its  side.  This  arrange- 
ment establishes  an  embryonic  renal  portal  system,  the  subclavian 
veins  and  caudal  branches  being  the  advehent  veins  while  the  pos- 
terior cardinal  veins  function  as  the  revehent  veins. 

With  the  further  development  of  the  mesonephroi,  changes  take 
place  rapidly.  The  mesonephroi  present  a  condensed  appearance 
in  the  posterior  region  while  the  anterior  portion  is  apparently  be- 
ginning to  atrophy.  The  posterior  cardinals  take  up  a  more  lat- 
eral position  to  the  mesonephroi  and  greatly  increase  in  size.  The 
anastomoses  between  the  posterior  cardinal  veins  and  the  subcar- 
dinal veins,  and  between  the  two  subcardinal  veins  increase  ex- 
tensively. 

When  the  stage  in  development  as  represented  by  an  embryo  of 
13  mm.  length  (Plate  IV)  is  reached,  the  majority  of  the  anasto- 
mosing connections  no  longer  lie  near  the  surface  but  dip  deep  into 
the  mesonephric  body  sending  venous  pockets  between  the  tubules. 
One  of  the  most  important  developing  structures  during  this  period 
is  the  postcaval  vein.  The  posterior  portion  of  this  vein  develops 
from  the  subcardinal  veins,  chiefly  the  right.  The  development  as 
found  in  this  species  duplicates  that  as  found  by  Stromsten  ('05) 
in  Kinosternon  pennsylvanicum. 

The  formation  of  the  postcava  which  opens  a  new  channel  for 
the  blood  to  reach  the  heart  is  accompanied  by  an  important  change 
in  the  embryonic  renal  portal  system  previously  established.  This 
change  is  completed  by  the  change  in  position  of  the  two  branches 
of  the  caudal  vein.  These  branches  were  previously  connected  with 
the  posterior  ends  of  the  subcardinal  veins.  Through  a  shifting 
of  the  anastomosing  connections  between  the  subcardinals,  post- 
cardinals  and  caudal  branches,  the  connection  between  the  caudal 
branches  and  the  subcardinal  veins  is  lost  and  there  is  a  connection 
established  between  the  caudal  branches  and  the  posterior  cardinal 
veins.  With  this  new  arrangement  the  blood  is  routed  differently, 
the  posterior  cardinals  and  the  caudal  branches  becoming  the  adve- 
hent veins  while  the  subcardinal  veins  and  the  postcava  become  the 
revehent  veins. 

The  anterior  portion  of  the  vertebral  vein  has  been  completed  at 
this  age,  being  connected  to  the  posterior  cardinal  vein  by  the  dor- 
sal segmental  veins.  The  posterior  region  has  not  yet  been  formed 
but  the  process  of  development  is  under  way  as  shown  in  Plate  IV. 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  21 

Following  this  stage  in  development  there  is  a  gradual  approach 
toward  the  condition  as  found  in  the  adult.  The  mesonephroi  in 
the  anterior  region  become  more  and  more  separated  from  the  dor- 
sal body  wall.  As  development  progresses  they  continue  to  de- 
generate in  the  anterior  region  while  posteriorly  they  are  large 
and  compact. 

This  anterior  degeneration  of  the  mesonephroi  is  accompanied 
by  the  degeneration  of  the  anterior  region  of  the  posterior  cardi- 
nal veins  and  their  dorsal  segmental  branches.  A  typical  condi- 
tion at  this  time  is  represented  by  reconstruction  figures  of  Plate 
V  made  from  an  embryo  measuring  8  mm.  carapace  length.  The 
posterior  cardinal  veins  still  show  the  connections  anteriorly  in 
the  regions  of  the  subclavian  vein  but  instead  of  a  single  large 
connection  there  are  several  small  ones  producing  a  network  be- 
tween the  anterior  end  of  the  posterior  cardinal  vein  and  the  duct 
of  Cuvier.     The  degeneration  process  is  quite  apparent. 

The  degeneration  of  the  anterior  dorsal  segmental  branches  is 
almost  complete  at  this  time,  severing  entirely  the  anterior  portion 
of  the  vertebral  vein  and  the  anterior  portion  of  the  degenerating 
posterior  cardinal  vein.  Posteriorly,  the  dorsal  segmental  branches, 
which  have  in  the  meantime  developed,  still  persist,  uniting  the 
vertebral  veins  to  the  posterior  portions  of  the  posterior  cardinals. 

The  posterior  cardinals  in  the  region  of  the  mesonephroi  are 
large  and  lie  laterally  within  the  periphery  of  these  organs  sending 
into  the  substance  of  the  mesonephroi  numerous  small  branches 
which  anastomose  freely  with  the  remainder  of  the  subcardinals 
or  the  posterior  region  of  the  postcava.  This  network  at  this  stage 
is  quite  complex  and  represented  in  Plate  V  semidiagrammatically. 
Its  character  has  been  determined  by  a  careful  study  of  cross  sec- 
tions and  longitudinal  sections  of  injected  embryos. 

The  mesonephros  continues  to  become  shorter  and  thicker  due 
to  the  degeneration  proceeding  in  the  anterior  portion.  The  split- 
ting away  from  the  dorsal  body  wall  proceeds  from  anterior  to 
posterior.  At  about  this  stage  the  metanephros  appears  as  a  dor- 
sal outgrowth  from  the  mesonephric  duct,  growing  anteriorly  and 
maintaining  its  position  dorsally. 

A  general  shortening  of  the  renal  portal  system  is  in  progress. 
The  posterior  cardinal  veins  lose  their  slight  connection  with  the 
duct  of  Cuvier  anteriorly  and  rapidly  undergo  degeneration  in 
the  anterior  region  (Plate  VI).     In  the  region  of  the  largest  por- 


22  IOWA  STUDIES  IN  NATUEAL  HISTORY 

tion  of  the  mesonephros  and  metanephros  the  posterior  cardinal 
veins  lie  lateral  to  these  organs  and  are  quite  large.  Posteriorly 
these  vessels  diminish  in  size  forming  the  posterior  renal  advehent 
veins.  The  posteava  has  increased  in  size  and  the  subcardinal 
anastomosis  has  not  entirely  disappeared.  The  mesonephric  plexus 
has  become  still  more  complex  and  consists  of  much  smaller  blood 
passages  than  those  in  the  previous  stage.  The  dorsal  segmental 
branches  anterior  to  the  fifth  rib  have  all  degenerated.  Those  pos- 
terior to  the  seventh  rib  have  likewise  degenerated  leaving  but  two, 
one  between  the  fifth  and  sixth  ribs  and  one  between  the  sixth  and 
seventh  ribs.  The  anterior  portion  of  the  vertebral  vein  is  now 
entirely  free  from  the  posterior  cardinal  vein  and  is  considerably 
larger  than  that  lying  posterior  to  the  sixth  rib. 

The  mesonephroi  continue  to  degenerate  from  anterior  to  pos- 
terior and  the  metanephroi  continue  to  develop  from  posterior  to 
anterior,  the  twTo  becoming  about  the  same  size  in  an  embryo  of  22 
mm.  carapace  length  (Plate  VII). 

The  vertebral  veins  are  completely  formed  at  this  time  and  re- 
ceive the  intercostal  veins.  The  connection  between  the  vertebral 
veins  and  the  posterior  cardinal  veins  lying  between  the  sixth  and 
seventh  ribs  as  described  in  the  embryo  of  a  twelve  millimeter  cara- 
pace has  now  disappeared,  leaving  one  large  prominent  connection 
between  the  fifth  and  sixth  ribs. 

The  posterior  cardinal  veins  have  completely  degenerated  an- 
terior to  the  mesonephroi  and  metanephroi.  That  portion  of  the 
posterior  cardinal  vein  lying  along  the  mesonephros  becomes  em- 
bedded between  the  mesonephros  and  the  metanephros,  giving 
branches  to  each  of  them.  This  is  brought  about  by  the  fact  that 
the  vein  lies  along  the  dorsal  surface  of  the  mesonephros.  The 
metanephros  developing  dorsal  to  the  mesonephros  gradually  as- 
sumes a  position  dorsal  to  the  vein  so  that  the  vein  lies  between  the 
two.  In  addition  to  this  vein  as  a  blood  supply  there  has  resulted 
at  this  stage  during  the  process  of  degeneration  of  the  mesonephros 
a  second  and  smaller  vein,  a  branch  of  the  embedded  vein,  which 
lies  posteriorly  along  the  lateral  surface  of  the  degenerating  mesone- 
phros. This  vein  I  have  termed  the  lateral  mesonephric  vein.  With 
further  development  this  vein  disappears  with  the  mesonephros. 

The  venous  plexus  of  the  metanephroi  during  this  later  period  of 
growth  is  constantly  becoming  one  of  finer  vessels  as  is  shown  by 
both  stained  and  injected  embryos. 


KENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  23 

Except  for  the  portions  of  the  subcardinal  veins  which  enter  into 
the  formation  of  the  posterior  portion  of  the  postcaval  vein  and 
metanephrie  venous  plexus  they  entirely  disappear.  The  changes 
taking  place  in  the  further  development  are  not  of  great  conse- 
quence. The  mesonephros  continues  to  degenerate  until  it  disap- 
pears and  the  metanephros  continues  to  develop  until  it  reaches 
full  size.  The  renal  portal  vein  maintains  its  position  and  appears 
in  the  adult  on  the  ventral  surface  of  this  organ.  The  larger  veins 
of  the  venous  plexus  of  the  metanephros  continue  to  be  broken  up 
into  finer  vessels  until  a  complete  capillary  network  exists  between 
the  renal  portal  vein  and  the  posterior  terminal  branches  of  the 
postcaval  vein.  Thus  there  is  established  a  true  renal  portal  sys- 
tem, the  advehent  veins  of  which  are  the  vertebrals,  iliaes,  renal  por- 
tals and  posterior  advehentes,  while  the  revehent  vein  is  the  post- 
cava  and  its  posterior  terminal  branches. 

IV.    DISCUSSION 

In  the  embryology  of  the  renal  portal  system  of  Chrysemys  mar- 
ginaia  belli  there  occurs  the  usual  three  important  periods  in  struc- 
tural development.  There  is  a  constructive  period  during  which 
various  structures  are  developed,  a  period  of  degeneration  equally 
as  important  in  respect  to  the  final  result,  and  a  period  of  rear- 
rangement and  development  of  the  organs  functioning  in  the  adult. 
These  periods  are  not  distinctly  marked  off  from  each  other  but 
one  gradually  merges  into  the  other  as  the  necessity  for  the  change 
arises. 

Due  to  the  polarity  of  the  embryo  the  anterior  region  develops 
first  and  remains  in  advance  of  the  posterior  region.  Likewise  any 
degeneration  occurring  originates  in  the  anterior  region  and  pro- 
ceeds posteriorly. 

The  early  formation  of  the  anterior  portion  of  the  posterior  car- 
dinal veins  seems  to  be  shrouded  in  considerable  doubt.  The  dif- 
ficulty of  following  them  during  the  earliest  period  of  develop- 
ment has  led  to  various  ideas  as  to  their  origin.  The  prevailing 
idea  of  their  origin  is  that  advanced  by  Hoffmann,  that  they  arise 
as  longitudinal  anastomoses  between  the  intersegmental  arteries. 
In  view  of  the  fact  that  I  wish  to  deal  with  their  later  development 
and  its  influence  in  the  establishment  of  a  renal  portal  system  I 
shall  pass  by  this  early  stage  of  the  formation  of  the  anterior  por- 
tion of  these  veins. 

The  studies  of  the  posterior  cardinal  veins  in  Elasmobranch 


24  IOWA  STUDIES  IN  NATURAL  HISTORY 

embryos  by  Hoffmann,  Balfour  and  Hochstetter  agree  quite  closely, 
in  so  far  as  my  observations  go,  with  this  form  of  Chelonia.  In  the 
Selachians  these  veins  are  found  in  early  embryos  to  be  two  short 
veins  lying  closely  beside  the  mesonephric  duct  and  gradually  grow- 
ing posteriorly  until  they  reach  the  full  length  of  the  mesonephroi. 
It  is  in  much  the  same  manner  that  they  behave  in  the  turtle.  How- 
ever, here  I  may  add  that  the  term  "growth  posteriorly"  would 
be  a  general  term  since  in  reality  a  series  of  blood  sinuses  unites  to 
form  the  posterior  cardinal  veins,  the  progress  of  the  unions  being 
from  anterior  to  posterior.  In  an  embryo  of  7  mm.  length  these 
vessels  have  not  yet  been  laid  down  the  full  length  of  the  mesone- 
phroi, but  this  condition  is  attained  in  an  embryo  of  10  mm.  length. 

According  to  Hochstetter  ('88)  in  Selachians  the  subintestinal 
vein  plays  a  conspicuous  part  in  the  formation  of  the  renal  portal 
system.  In  Chelonia  another  group  of  vessels  is  concerned  in 
serving  the  same  purpose  as  the  subintestinal  vein  in  Selachians. 
The  shifting  of  the  caudal  vein  branches  and  the  posterior  cardinal 
veins  establishes  a  renal  portal  system  in  the  adult  Selachian. 
While  this  shifting  of  the  caudal  vein  branches  does  occur 
in  the  turtles  Chrysemys  marginata  helix  and  Kinosternon 
pennsylvanicum,  the  same  structures  are  not  affected  in  the 
Selachians  as  in  the  Chelonia.  This  is  due  to  the  fact  that 
in  the  higher  type  of  vertebrate,  a  new  vessel,  the  post- 
cava,  has  arisen  and  functions  in  place  of  the  anterior  portions  of 
the  posterior  cardinal  veins  which  atrophy. 

In  Chrysemys  marginata  belli  we  find  the  Selachian  stage  of 
development  of  the  renal  portal  system  at  its  height  when  the 
mesonephroi,  posterior  cardinal  veins,  subcardinal  veins  and  the 
caudal  vein  with  its  branches  are  functioning  most  efficiently.  At 
this  time  the  fact  that  a  great  change  is  imminent  may  be  discerned 
by  the  presence  of  conspicuous  vertebral  blood  sinuses  and  the 
initial  formation  of  the  dorsal  segmental  veins  which  appear  to 
grow  dorsally  from  the  posterior  cardinal  veins. 

For  a  comparison  of  the  development  of  the  veins  of  the  renal 
portal  system  of  this  species  of  turtle  with  those  of  other  Amniota 
we  may  turn  our  attention  to  the  work  of  Rathke  on  snakes,  Hoff- 
mann and  Hochstetter  on  lizards  and  Stromsten  on  turtles. 

The  posterior  cardinal  veins  in  Chrysemys  marginata  lying  on 
the  surface  of  the  mesonephroi  in  early  embryonic  stages  are  ap- 
parently in  sufficiently  close  relation  to  the  mesonephric  tissues 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  25 

so  that  they  can  efficiently  take  care  of  these  organs  but  with  an 
increase  in  the  volume  of  these  bodies  the  veins  must  necessarily 
maintain  their  close  association  with  the  tubules.  The  surface  of 
the  growing  mesonephros  becomes  somewhat  rough  due  to  the  in- 
crease in  number  and  size  of  the  tubules.  As  a  result,  the  posterior 
cardinal  veins  and  subcardinal  veins  closely  adhering  to  the  sur- 
face become  somewhat  pocketed  and  these  pockets  extend  inwardly 
between  the  mesonephric  tubules.  With  continued  growth  of  the 
mesonephroi  the  pockets  increase  in  size  and  number  and  eventually 
those  from  the  subcardinal  unite  with  those  from  the  posterior 
cardinal.  The  earliest  unions  of  the  pockets  are  formed  on  the  dor- 
sal and  ventral  surfaces  of  the  mesonephroi  so  that  a  circulation  is 
established  between  these  two  groups  of  veins.  This  arrangement 
is  almost  identical  with  that  found  by  Lewis  ('02)  in  the  rabbit 
and  probably  corresponds  with  the  intertubular  vascular  spaces  of 
Minot.  Later  these  connections  penetrate  the  organs  making  a 
coarse  network  which  with  development  is  broken  up  into  a  finer 
network  of  capillaries  (or  sinusoids).  The  anterior  portions  of  the 
posterior  cardinals,  in  the  region  of  their  union  with  the  duct  of 
Cuvier,  while  originally  large  single  vessels,  break  up  later  into 
several  small  venous  connections  (Plate  V).  This  condition  is 
due  to  the  process  of  degeneration  in  this  region. 

The  formation  of  the  vertebral  veins  in  Chrysemys  marginata 
begins  quite  early.  In  fact  there  is  indication  of  their  formation 
as  early  as  the  7  mm.  stage.  This  is  previous  to  the  complete  forma- 
tion of  either  the  posterior  cardinal  veins  or  the  subcardinal  veins 
and  before  a  fusion  exists  between  the  subcardinals.  There  is  al- 
ready a  chain  of  blood  sinuses  laid  down  in  the  position  to  be  oc- 
cupied by  the  vertebral  vein.  This  early  development  of  venous 
sinuses  in  turtles  as  anlagen  for  veins  corresponds  to  the  develop- 
ment of  the  posterior  cardinals  and  subcardinals  in  birds  as  re- 
corded by  Miller  ('03).  In  the  early  stages  of  the  development  of 
Chrysemys  marginata  the  posterior  cardinal  veins,  the  subcardinal 
veins  and  the  vertebral  veins  all  show  this  primitive  type  of  de- 
velopment. The  vertebral  vein  originates  as  has  been  described,  by 
the  dorsal  segmental  branches  passing  dorsal  to  the  anlagen  of  the 
ribs  and  through  anastomoses  with  intervening  blood  sinuses.  The 
formation  of  this  vein  is  a  progressive  process  beginning  at  the  an- 
terior end  and  proceeding  posteriorly.  This  same  method  of  origin, 
other  than  the  inclusion  of  the  blood  sinuses,  has  been  described 
by  Stromsten  ('05)  in  Kinostemon  pennsylvanicum  and  by  Kim- 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

ball  ('23)  for  Chrysemys  marginata  belli.  As  has  already  been 
pointed  out  by  Stromsten,  the  development  of  the  vertebral  veins 
in  turtles  differs  from  the  development  in  the  lizards,  as  recorded 
by  Hochstetter,  in  that  they  develop  dorsal  to  the  rib  anlagen  in 
the  former  and  ventral  to  them  in  the  latter. 

The  subcardinals  originally  laid  down  as  a  series  of  anastomos- 
ing venous  sinuses  are  well  established  in  an  embryo  of  10  mm. 
length  with  a  strong  interanastomosis  posterior  to  the  omphalo- 
mesenteric artery  (Plate  III).  These  continue  to  develop  and 
establish  intimate  connections  between  themselves  and  the  pos- 
terior cardinal  veins  so  that  at  the  stage  of  13  mm.  length  there 
exists  a  very  extensive  network  of  connections  posterior  to  the 
omphalo-mesenteric  artery,  not  only  between  the  posterior  cardi- 
nal veins  and  the  subcardinal  veins,  but  also  between  the  two  sub- 
cardinals.  Since  these  connections  are  posterior  to  the  omphalo- 
mesenteric artery  there  is  no  venous  ring  formed  as  described  by 
Hochstetter  in  the  development  of  Lacerta  agilis.  In  regard  to  the 
dense  network  formed  here,  this  agrees  favorably  with  the  lizards 
and  with  Kinosternon  pennsylvanicum. 

While  the  previous  changes  have  been  taking  place,  the  branches 
of  the  caudal  vein,  through  sinusoidal  changes  have  had  their  con- 
nections with  the  subcardinal  veins  shifted  to  the  postcardinal  veins. 

During  these  developmental  stages  the  postcava  has  also  begun 
to  appear  and  has  assumed  a  highly  developed  condition  at  the  time 
the  branches  of  the  caudal  vein  shift  from  the  subcardinal  veins 
to  the  posterior  cardinal  veins.  Among  the  animals  possessing  this 
vessel  there  is  considerable  variation  in  the  method  of  its  formation. 
This  accounts  for  the  various  types  of  its  expression  in  the  adults, 
Goette  in  his  work  on  Bombinator  igneus  describes  the  develop- 
ment of  the  posterior  portion  of  the  postcava  as  being  formed  by 
the  union  of  the  posterior  cardinal  veins  which  approach  each  other 
and  fuse  in  this  region.  Balfour  believes  this  to  be  incorrect  since 
the  Amniota  as  described  by  Rathke  and  others  show  no  such  pro- 
cess. In  the  lizard,  Lacerta  viridis,  as  described  by  Hochstetter, 
the  extreme  posterior  portion  of  the  postcava  is  formed  from  the 
two  branches  of  the  caudal  vein  and  exists  in  the  adult  as  a  bifur- 
cated vessel  posteriorly.  In  Chrysemys  marginata  belli  I  find  the 
development  of  its  posterior  region  to  wholly  corroborate  that  as 
given  by  Stromsten  for  Kinosternon  pennsylvanicum,  that  is,  in 
this  region  it  is  formed  by  the  "  right  subcardinal  craniad  of  the 


EENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  27 

origin  of  the  omphalo-mesenteric  artery  and  the  fused  subcardinals 
caudad  of  this  point/' 

When  the  development  has  reached  this  stage  the  degenerative 
factor  assumes  prominence.  Previous  to  the  formation  of  the 
postcava,  the  vertebral  vein  and  the  shifting  of  the  caudal  veins, 
the  blood  was  carried  from  the  caudal  region  by  the  caudal  vein 
and  through  its  branches  was  poured  into  the  subcardinal  veins. 
It  then  passed  through  the  venous  plexus  of  the  mesonephros  into 
the  posterior  cardinal  veins  which  carried  it  anteriorly  and  dis- 
charged it  into  the  ducts  of  Cuvier. 

Now  a  new  condition  arises.  The  functioning  of  the  postcava 
allows  the  blood  to  make  a  short  cut  to  the  heart.  As  a  result  of 
this,  the  posterior  cardinal  veins  lose  their  connections  with  the 
ducts  of  Cuvier  and  degenerate.  As  found  in  lizards  by  Hoch- 
stetter  this  condition  is  accompanied  by  the  separation  of  the  an- 
terior region  of  the  mesonephroi  from  the  dorsal  body  wall  and  the 
progressive  degeneration  of  the  mesonephroi  and  dorsal  segmental 
veins.  The  posterior  progressive  degeneration  of  the  mesonephros 
is  probably  aided  by  the  development  of  the  metanephros  which 
appears  at  about  this  time  (Plate  VI).  A  rapid  growth  of  the 
limb  buds  and  the  consequent  relative  reduction  of  the  caudal  re- 
gion causes  an  increase  in  the  size  of  the  iliac  vein  and  a  reduction 
in  importance  of  the  posterior  vertebral  veins.  This  results  in  an 
enlargement  of  the  iliac  veins  and  a  reduction  in  the  size  of  the 
vertebral  veins  posterior  to  the  kidneys.  This  progressive  degen- 
eration continues  until  the  only  connection  remaining  between  the 
vertebral  vein  and  the  posterior  region  of  the  posterior  cardinal 
vein  is  that  as  previously  described  lying  between  the  fifth  and 
sixth  ribs.  The  portion  of  the  posterior  cardinal  vein  which  fails 
to  atrophy  is  that  lying  along  the  latero- ventral  surface  of  the  kid- 
ney and  dorsal  to  the  degenerating  mesonephros.  The  lateral 
mesonephric  vein  is  still  present.  The  vein  connecting  the  undegen- 
erated  portion  of  the  posterior  cardinal  vein  with  the  vertebral 
vein  becomes  the  anterior  renal  advehent  vein. 

"With  this  arrangement  the  blood  flow  is  reversed.  The  blood 
now  passes  from  the  vertebral  vein,  the  iliac  vein  and  the  caudal 
veins  into  the  renal  portal  vein  and  from  here  through  the  venous 
network  of  the  mesonephros  and  kidney  into  the  postcava. 

Degeneration  of  the  mesonephros  continues  simultaneously  with 
the  growth  of  the  kidneys.    With  the  degeneration  of  the  remain- 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

ing  portion  of  the  mesonephros  the  lateral  mesonephric  vein  dis- 
appears leaving  the  vein  tying  ventro-lateral  to  the  kidney  as  the 
only  persisting  part  of  the  posterior  cardinal  vein.  The  kidney 
now  takes  the  place  of  the  mesonephros. 

As  the  foregoing  changes  take  place  the  venous  network  of  the 
kidney  becomes  broken  into  more  minute  vessels  until  only  a  fine 
network  exists.  This  network  of  capillaries  (or  sinusoids)  has 
been  tested  as  previously  stated,  by  injections,  by  casts  and  by 
serial  sections  and  in  every  case  I  find  definite  capillary  connec- 
tions (or  sinusoids)  which  may  be  traced  between  the  renal  por- 
tal vein  and  branches  of  the  postcava  but  in  no  case  have  I  found 
a  connection  larger  than  capillary  size. 

This  arrangement  then  produces  a  renal  portal  system  in  this 
form,  the  blood  entering  the  kidney  through  the  renal  portal  vein, 
traversing  the  capillary  plexus  of  the  kidney  and  leaving  by  the 
postcava. 

Y.     SUMMARY 

Previous  workers  have  found  a  true  renal  portal  system  present 
in  adult  forms  of  fishes,  Amphibians,  lizards  and  snakes,  but  absent 
in  birds  and  mammals.  Occasionally  suggestions  have  been  made  of 
the  possibility  of  the  transitional  stages  being  found  in  the  Chelon- 
ian  group. 

Selachians 

The  early  development  of  the  renal  portal  system  in  Chrysemys 
marginata  belli  is  fundamentally  the  same  as  the  development  of 
the  renal  portal  system  in  the  Selachians.  The  chief  differences  are 
that  in  Chelonia  the  postcava  is  substituted  for  the  anterior  por- 
tions of  the  posterior  cardinal  veins  of  the  Selachians  and  the  sub- 
cardinal  veins  in  Chelonia  are  substituted  for  the  subintestinal  vein 
in  Selachians. 

The  later  development  in  Chelonia  carries  it  far  beyond  the 
Selachian  stage  and  agrees  to  a  considerable  extent  with  that  as 
found  in  other  reptiles  and  Amphibia,  although  several  important 
differences  in  development  appear. 

Amphibia 
In  Amphibia  as  described  by  Goette  the  posterior  portion  of  the 
postcava  is  formed  from  the  fused  portions  of  the  posterior  cardi- 
nal veins  while  in   Chelonia  it  is  formed  from  the  subcardinal 
veins. 


EENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  29 

Lizards 

In  lizards,  the  records  of  the  earliest  stages  of  development  of 
the  posterior  cardinal  veins  and  the  subcardinal  veins  describe 
them  as  continuous  connected  blood  vessels.  The  earliest  stages 
of  these  vessels  as  observed  in  Chrysemys  marginata  belli  show 
them  to  be  discontinuous  vessels  with  no  connections. 

The  formation  of  venous  pockets  by  the  posterior  cardinal  and 
subcardinal  veins  is  not  described  for  lizards.  These  venous  pockets 
are  quite  definite  and  distinct  in  this  form  of  Chelonia  and  enter 
into  the  formation  of  the  venous  network  of  the  mesonephros  and 
metanephros. 

The  vertebral  veins  of  the  lizards  develop  ventral  to  the  rib 
anlagen  by  anastomosing  dorso-segmental  branches. 

The  posterior  portion  of  the  postcava  in  lizards  develops  through 
anastomosis  with  the  omphalo-mesenteric  ring.  In  Chelonia,  since 
there  is  no  complete  omphalo-mesenteric  ring  present  it  develops 
from  a  portion  of  the  right  subcardinal  vein  and  the  anterior  re- 
gion of  the  fused  subcardinal  veins. 

Snakes 

In  snakes  the  posterior  portion  of  the  postcava  is  developed  as  a 
bifurcated  vessel  while  in  Chelonia  it  is  a  single  vessel  in  this  region. 

The  posterior  vertebral  veins  are  prominent  in  the  snake  embryo 
and  develop  ventral  to  the  rib  anlagen.  They  finally  disappear, 
leaving  little  or  no  trace  in  the  adult  while  in  Chelonia  they  remain 
as  definite  veins. 

Chrysemys  marginata  belli  (Gray) 

1.  The  posterior  portions  of  the  posterior  cardinal  and  subcardi- 
nal veins  are  formed  by  anastomosing  blood  sinuses. 

2.  The  posterior  cardinal  and  subcardinal  veins  become  pock- 
eted, these  pockets  lying  between  the  mesonephric  tubules. 

3.  The  venous  pockets  unite  to  form  venous  connections  be- 
tween the  posterior  cardinal  and  subcardinal  veins. 

4.  The  subcardinal  veins  fuse  posterior  to  the  omphalo-mesen- 
teric artery  only. 

5.  The  renal  portal  vein  is  the  persisting  portion  of  the  pos- 
terior cardinal  which  lies  between  the  mesonephros  and  metane- 
phros. 

6.  The  anterior  renal  advehent  vein  is  the  persisting  dorso-seg- 
mental branch  of  the  posterior  cardinal  which  lies  between  the  fifth 
and  sixth  ribs. 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

7.  The  vertebral  vein  develops  from  anastomosing  branches  of 
the  dorso-segmental  veins  and  intervening  blood  sinuses. 

8.  The  connections  formed  by  the  union  of  the  venous  pockets 
of  the  posterior  cardinal  and  subcardinal  veins  become  broken  up 
into  a  network  of  capillaries  (or  sinusoids)  which  persist  and  form 
an  intra-renal  network  in  the  adult. 

9.  A  true  renal  portal  system  is  present  in  the  adult  form. 

LITERATURE 

Agassiz,  Louis,  57.    Contributions  to  the  Natural  History  of  the  United  States, 

Vol.  II,  Part  III.     Embryology  of  the  Turtle;   with  thirty-four  plate3. 

Boston. 
Balfour,    F.    M.,    78.     A   Monograph   on   the   Development   of   Elasmobraneh 

Fishes. 

81.     A   Treatise  on  Comparative  Embryology,  Vol.   11. 
Gegenbauer,  Carl.     Elements  of  Comparative  Anatomy.     Trans.     F.  Jeffrey 

Bell. 
Goette,  Alexander,   75.     Die  Entwicklungsgeschichte  der  Unke. 
Hertwig,   O.,   06.     Handbueh   der   Vergleiehenden   und   Experimentellen   Ent- 

wicklungslehre  der  Wirbeltiere,  Vol.  III. 
Hochstetter,    F.,    88.      Beitrage   zur   vergleiehenden    Anatomie   und   Entwick- 
lungsgeschichte  des   Venensy stems   der   Amphibien   und   Fische.     Morph. 

Jahrb.,  B.  XIII. 

88.     Ueber    den   Einfluss    der    Entwickelung    der    bleibenden 

Meren  auf  die  Lage  des  Urnierenabschnittes  der  hinteren  Cardinalvenen. 

Anat.  Anz.,  B.  III. 

93.     Beitrage   zur   Entwicklungsgeschichte   des  Venensystems 

der  Amnioten.     II.     Beptilien.     Morph.     Jahrb.,  B.  XIX. 
Hoffman,    C.    K.,    84.      Beitrage    zur    Entwicklungsgeschichte    der    Beptilien. 

Zeitsch.  f.  Wiss.     Zoologie,  B.  40. 

90.     Bronn's  Klassen  und  Ordnungen  des  Thierreichs,  B.  VI, 

Abth.    Ill,   Beptilien.      Leipzig. 
Hoffman,  C.  K.,  93.     Zur  Entwicklungsgeschichte  des  Venensystems  bei  den 

Selaehiern.     Morph.  Jahrb.,  B.  XX. 
Jourdain,  S.,  59.     Sur  le  Systeme  V.  porte  renale.     Ann.  des  Sc.  Nat.,  4  Ser., 

T.  XII. 
Kimball,  Pauline,  23.     A  Contribution  to  the  Anatomy  and  the  Development 

of  the  Arterial  and  Venous  Systems  in  Turtles.     The  Anatomical  Kecord, 

Vol.   XXV. 
Lewis,  F.  T.,  02.     The  Development  of  the  Vena  Cava  Inferior.     American 

Journal  of  Anatomy,  Vol.  I. 

04.     The   Question    of   Sinusoids.        Anatomischer    Anzeigerr 

Vol.  XXV. 
Miller,  A.  M.,  03.     The  Development  of  the  Postcava  Vein  in  Birds.     Ameri- 
can Journal  of  Anatomy,  Vol.  II. 


RENAL  PORTAL  SYSTEM  IN  CHRYSEMYS  31 

Minot,   Charles   S.,  98.     On  the  Veins  of  the  Wolffian  Bodies  in  the  Pig. 

Proc.  Bost.  Soc.  of  Nat.  Hist.,  Vol.  XXVIII. 

00.     On   a   hitherto   unrecognized   form  of  blood   circulation 

without  capillaries  in  the  organs  of  Vertebrata.    Proc.  Bost.  Soc.  of  Nat, 

Hist.,  Vol.  XXXIX. 
Owen,  Bichard,  66.     Anatomy  of  Vertebrates,  Vol.  I. 
Bathke,  H.,  39.     Entwicklungsgeschichte  der  Natter.     Konigsberg. 

48.     Ueber  die  Entwicklung  der  Schildkroten.    Braunschweig. 
66.     Untersuchungen  uber  die  Entwicklung  und  den  Korper- 

bau  der  Krokodile. 
Kobinson  Byron  L.,  18.     Concerning  the  renal  portal  system  in  Chrysemys 

marginata.     Anatomical  Becord,  Vol.  XIV. 
Schreiner,   K.  E.,  Ueber   die  Entwicklung   der  Amniotenniere.     Zeitsch.     f. 

Wiss.     Zool.,  Bd.  71. 
Stromsten,  F.  A.,   '05.     A  Contribution  to  the  Anatomy  and  Development  of 

the  Venous   System  of  Chelonia.     The  American  Journal  of  Anatomy, 

Vol.  IV,  No.  4. 


PLATES 


EXPLANATION  OF  PLATES 

Plate        I.     Outline   drawings   of   embryos   whose   reconstructed   veins   appear 

in  plates  II-VII. 
Plate      II.     Frontal    and    right    lateral    reconstructions    of    the    veins    of    an 

embryo   7  mm.  long.      (See  PI.  I,   Fig.   1). 
Plate    III.     Frontal    and    right    lateral    reconstructions    of    the    veins    of    an 

embryo   10  mm.  long.      (See  PI.  I,  Fig.  2). 
Plate     IV.     Frontal  and  right  lateral  reconstruction  of  the  veins  of  an  embryo 

13  mm.  long.      (See  PI.  I,  Fig.  3). 
Plate       V.     Frontal  and  right  lateral  reconstruction  of  the  veins  of  an  em- 
bryo 8  mm.  carapace  length.      (See  PI.  I,  Fig.  4). 
Plate     VI.     Frontal  and  right  lateral  reconstruction  of  the  veins  of  an  em- 
bryo  12  mm.  carapace  length.      (See  PI.  I,  Fig.  5). 
Plate  VII.     Frontal  and  right  lateral  reconstruction  of  the  veins  of  an  embryo 
22   mm.  carapace  length.      (See  PI.   I,  Fig.   6). 

Outline   of  mesonephros. 

Outline   of  metanephros. 

Heavy  horizontal  lines  indicate  the  level  of  the  spinal  ganglia. 

Ao.  Aorta. 

Bl.S.Pc.      Posterior  cardinal  blood  sinuses. 

Bl.S.Sc.      Subcardinal   blood   sinuses. 

Bl.S.V.       Vertebral  blood  sinuses. 

D.C.D.        Ductus  Cuvier  Dextra. 

D.C.S.         Ductus  Cuvier   Sinistra. 

D.Seg.Br.  Dorso-segmental  branches. 

L.A.  Longitudinal   anastomosis. 

M.P.  Mesonephric  plexus.  ' 

Pc.Sc.A.     Posterior   cardinal  and  subcardinal   anastomosis. 

Sc.Sc.A.      Subcardinal    and    subcardinal    anastomosis. 

V.Ac.D.      Vein   anterior   cardinal   dextra. 

V.Ac.S.       Vein  anterior  cardinal  sinistra 

V.C.  Postcava. 

V.C.A.        Postcava  anastomosis. 

V.Ca.D.      Vein   caudalis   dextra. 

V.Ca.S.       Vein   caudalis   sinistra. 

V.D.Seg.    Vein  dorso  segmental. 

V.Ext.J.     Vein  external  jugular.  " "   f 

V.I.E.D.     Vein   iliac   externa    dextra. 

V.I.E.S.      Vein  iliac  externa   sinistra. 

V.Int.J.      Vein  internal  jugular. 

V.L.B.D.    Vein  limb  bud  dextra. 

V.L.B.S.     Vein  limb  bud  sinistra. 

V.Pc.D.       Vein   posterior   cardinal   dextra. 

V.Pc.S.       Vein  posterior  cardinal  sinistra. 

V.E.A.D.    Vein  revehens  anterior  dextra. 

V.E.A.S.    Vein   revehens   anterior   sinistra. 

V.E.P.D.    Vein   renal   portal   dextra. 

V.E.P.S.     Vein  renal  portal  sinistra. 

V.Sc.D.       Vein  subcardinal  dextra. 

V.Sc.S.       Vein    subcardinal   sinistra. 

V.Sbc.D.    Vein   subclavian  dextra. 

V.V.D.        Vein  vertebral  dextra. 

V.V.S.         Vein  vertebral  sinistra. 


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UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  4 


ENTOMOLOGICAL  AND  GEOLOGICAL 

PAPERS 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


CONTENTS 


Ants  Collected  by  the  University  of  Iowa  Fiji- 
New  Zealand  Expedition  W.  M.  Mann 

The  Wasp-like  Insects  or  Hymenoptera,  Exclusive  of  Ants, 
Collected  by  the  Barbados-Antigua  Expedition 
from  the  University  of  Iowa  in  1918         Henry  Lorenz  Viereck 

Tipulidce  Collected  by  the  University  of  Iowa 
Fiji-New  Zealand  Expedition  Charles  P.  Alexander 

Photographic  Practice  for  Field  Geologists 

Chester  K.  Wentworth 

The  Desert  Strip  of  West  Molokai  Chester  K.  Wentworth 


ANTS  COLLECTED  BY  THE  UNIVERSITY  OF 
IOWA  FIJI-NEW  ZEALAND  EXPEDITION 

W.  M.  Mann 

Bureau  of  Entomology,  Department  of  Agriculture 

Through  the  kindness  of  Professor  Dayton  Stoner,  I  have  been 
able  to  examine  the  ants  which  he  collected  in  New  Zealand  and 
in  Fiji.  In  addition  to  new  locality  records  for  a  number  of  the 
endemic  Fijian  forms,  there  is  a  new  variety  of  Bogeria  (Irogera) 
tortuosa,  a  description  of  which  is  included  with  the  list  of  species. 

NEW  ZEALAND 

Ponera  antipodum  Forel 
Helensville. 

Euponera  (Mesoponera)  castanea  Mayr. 
Auckland. 

Monomorkim   (Notomyrmex)   antarcticum  F.  Smith 
Auckland ;  Helensville ;  Rotorua ;  Mt.  Rangitoto. 

FIJI 

Odontomachus  hcematodes  (Linne) 
Suva ;  Viria ;  Walu  Bay ;  Nukulau ;  Tamavua. 
Cardiocondyla  nuda  (Mayr.) 
Suva ;  Walu  Bay. 

Pheidole  megacephala  Fabr. 
Suva.  Several  workers  are  among  Professor  Stoner 's  material. 
In  my  paper  on  the  ants  of  Fiji  (Bull.  Mus.  Comp.  Zool.  Cam- 
bridge, Vol.  LXIV,  No.  5,  p.  403)  I  stated  that  I  had  not  taken 
megacephala  in  Lau  and  omitted  to  list  it  among  the  species  of 
Pheidole.  But  on  the  larger  islands,  especially  in  the  cultivated 
districts,  it  is  one  of  the  commonest  ants. 

Pheidole  oceanica  Mayr. 
Circular  Road,  Suva.     One  worker. 
Bogeria  (Irogera)   tortuosa  Mann  susbp.  stoneri,  new  subspecies 
Worker.     Length  3.50  mm. 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

Differing  from  typical  tortuosa  in  the  absence  of  striiB  on  sides  of  occiput, 
in  which  character  it  resembles  the  subspecies  levifrons  and  polita  but  is 
distinct  from  these  as  well  as  typical  tortuosa  in  the  structure  of  the  epinotum, 
the  base  of  which  is  longer  and  less  covex  and'  the  superior  spines  broader, 
widely  divergent  and  curved  forward  rather  strongly  instead  of  being  straight 
as  in  the  other  forms  of  the  species. 

Type  locality.  —  Tamavua,  Suva. 

Type.  —  In  the  museum  of  the  State  University  of  Iowa. 

Cotypes.  —  Cat.  No.  26487.    U.S.N.M. 

Described  from  two  workers. 

Tetramorium  (Tetrogmus)  simillimum  (Mayr.) 
Makaluva. 

Tetramorium    (Tetramorium)    pacificum  Mayr. 
Suva ;  Walu  Bay. 
Tetramorium   (Tetramorium)   pacificum  Mayr  var.  wilsoni  Mann 
Nukulau. 

Tapinoma  melanocephalum  (Fabr.) 
Nukulau. 

Technomyrmex  albipes  F.  Smith  var.  vitiensis  Mann 
Nukulau. 

Plagiolepis  longipes  (Jerd.) 
Suva ;  Makaluva ;  Nukulau. 

Camponotus   (Myrmogonia)   laminatus  Mayr. 
Tamavua. 

Camponotus  (Myrmogonia)   schmeltzii  Mayr. 
Suva. 
Camponotus  (Myrmoturba)  maculatus  (Fabr.)  subsp.  pallidus 

F.  Smith  var. 
Suva;  Viria. 

Camponotus   (Colobopsis)   dentata  Mayr. 
Makaluva. 

Camponotus  (Colobopsis?)  vitiensis  Mann 
Tamavua.     In  Professor  Stoner's  material  are  five  wrorkers  of 
this  species,  described  originally  from  the  mountains  at  Nadarivatu, 
and  placed,  with  doubt,  in  the  subgenus  Colobopsis. 


THE    WASP-LIKE    INSECTS    OR    HYMENOP- 
TERA,  EXCLUSIVE  OF  ANTS,  COLLECTED 
BY  THE  BARBADOS-ANTIGUA  EXPE- 
DITION FROM  THE  UNIVERSITY 
OF  IOWA  IN  1918 

Henry  Lorenz  Viereck 
Ottawa,  Ontario 

Of  the  thirty-eight  species  of  wasp-like  insects,  ants  excepted, 
brought  home  from  Barbados  and  Antigua  by  Dr.  Dayton  Stoner 
and  submitted  to  me  for  study,  I  find  that  eleven  are  either  new 
to  subdivision  4  of  the  Neotropical  Region  or  new  to  science. 

LIST  OF  SPECIES 

ICHNEUMONOIDEA 

Vipionidae 

Apanteles  (Apanteles)  sp. 
A  single  female  that  may  represent  a  new  species  related  to 
A.  (A.)  Icevicoxis  Muesebeck,  described  from  Utica,  Mississippi. 
Antigua,  July  (Stoner). 

Apanteles  (Apanteles)  sp. 
A  female  and  male  presumably  related  to  A.  (A.)  ensiger  Say. 
Antigua,  July  15-18  (D.  &  L.  Stoner). 

Apanteles  {Trot apanteles)  sp. 
One  female  that  may  prove  to  be  the  same  as  A.  (P.)  floridanus 
Muesebeck. 

Antigua,  July  (Stoner). 

Microbracon  quintilis  new  species 
Female.  —  Length  2.5  mm. ;  head  above  and  thorax  throughout  as  if  covered 
with  a  brownish-yellow  lacquer,  face  and  mouth  parts  yellowish,  excepting 
the  blackish  tips  of  the  mandibles,  antenme  23-jointed,  black  or  blackish, 
except  for  the  apical  and  basal  edges  of  the  scape  and  pedicel  which  are 
more  or  less  pale ;  tegulae  transparent,  yellowish,  wings  inf usoated,  their 
veins  blackish  and  yellowish,  the  costa  between  wing-base  and  stigma  mostly 
yellowish,  stigma  yellowish  with  a  blackish  edge,  legs,  mostly,  more  or  less 

7 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

concolorous  with  the  thorax,  end  joint  of  fore-tarsi  and  all  joints  of  mid  and 
hind-tarsi  more  or  less  brownish  to  blackish,  hind  tibiae  yellowish  except  for  the 
apical  third  which  is  more  or  less  blackish;  propodeum  polished  with  a 
rudimentary  median  carina  at  apex;  abdomen  yellowish  throughout,  finely 
shagreened,  almost  sculptureless,  first  tergite  with  an  inconspicuous  apical 
carina,  second  tergite  with  an  elongate  impression  on  each  side  of  the  middle 
elevated  area  and  with  a  sublateral  impression  nearer  to  the  lateral  margin 
than  to  the  median  impressions,  apical  margin  of  second  tergite  emarginate, 
sheaths  of  the  ovipositor  longer  than  the  abdomen  but  shorter  than  the  latter 
and  the  thorax  combined,  end  sternite  pointed  and  extending  beyond  the 
corresponding  tergite. 

Allotype  —  Essentially  like  the  type  but  with  the  stigma  darker  and  with 
the  fourth,  fifth  and  sixth  tergites  brownish  black. 

Related  to  M.  dorsator  var.  mellitor  Say. 

Type  and  Allotype  —  Collection  University  of  Iowa. 

Type  locality  —  Antigua,  July  (Stoner). 

Microbracon  sp. 
One  female  related  to  the  preceding  and  probably  new  to  science. 
Antigua,  July  (Stoner). 

Braconidae 

BasstiSy  n.  sp. 
Two  female  specimens,  one  broken. 
Barbados,  June  7  (D.  Stoner)  ;  Antigua,  July  (Stoner). 

Chelonus  insularis  Cress. 
Many  specimens.     Antigua,  July  (Stoner). 

Chelonus  insularis  Cress. 
Variety  with  entirely  black  carapace.     Six  specimens.    Antigua, 
July  (Stoner). 

Ichneumonidae 

Neopristomerus  stoneri  new  species 
Female.  —  Length  7  mm. ;  head  and  thorax  mostly  reddish ;  antennae  appar- 
ently a  little  longer  than  head  and  thorax  combined,  transfacial  line  :  facial 
line  : :  26  :  21,  face  and  frons  virtually  equal  in  width,  shining,  closely  punctured, 
clypeus  yellowish,  polished,  sparsely  punctured  compared  with  the  face,  malar 
line  apparently  as  long  as  the  mandibles  are  wide  at  base,  greatest  diameter 
of  lateral  ocelli  a  little  shorter  than  the  ocelloeular  line  but  apparently  equal 
to  the  lateral  ocellar  line,  temples  shining,  convex,  apparently  impunctate, 
vertex  distinctly  punctured,  but  sparsely;  praescutum  paler  and  more  closely 
punctured  than  the  parapsides,  pronotum  along  the  upper  edge  polished  and 
sparsely  punctured,  elsewhere  mostly  shining  and  closely  punctured,  meso- 
pleura  and  metapleura  mostly  densely  punctured,  veins  and  stigma  mostly 
blackish,  the  latter  apparently  a  little  less  than  half  as  wide  as  long,  legs 
yellowish  to  reddish  except  for  the  end  joint  of  mid-tarsi,  hind  tibiffi  and 


HYMENOPTERA  OF  BARBADOS  AND  ANTIGUA        9 

hind  tarsi  all  of  which  are  more  or  less  brownish  to  blackish,  denticles 
rudimentary  between  tooth  and  apex  of  hind  femora,  longer  spur  of  hind 
tibiae  apparently  more  than  one-third  but  less  than  one-half  as  long  as  hind 
basitarsus;  propodeum  sculptured  much  like  metapleura,  areola  apparently 
twice  as  long  as  its  greatest  width,  costulaB  joining  the  longitudinal  carina 
almost  at  the  junction  of  the  basal  third  of  the  areola  with  the  apical  two- 
thirds;  abdomen  polished  or  nearly  so,  mostly  yellowish  to  brownish  yellow, 
second  tergite  a  little  shorter  than  the  first  and  together  with  the  apical  half 
of  the  first  and  the  basal  half  of  the  third  mostly  black  or  blackish,  basal 
half  of  the  first  tergite  mostly  stramineous,  second  tergite  two  and  one-half 
times  as  long  as  wide  at  base,  indefinitely  longitudinally  striate. 

Presumably  related  to  N.  melleus  Cushman. 
Type  —  Collection  University  of  Iowa. 
Type  locality  —  Antigua,  July  (Stoner). 

Enicospihis  purgatus  Say. 
Many  specimens. 

Antigua,  June  (Stoner).  One  S  specimen  from  the  above  lot 
and  that  may  be  a  variety  of  purgatus  goes  to  neotropicus  Hooker 
in  Hooker 's  key  because  it  has  only  one  corneous  area  in  each  wing. 

Chalcidoidea 
Elachertidae 

Euplectrus  sp. 
Two  females  of  what  may  prove  to  be  a  new  species.     Antigua, 
July  (Stoner). 

Pteromalidae 
Aplastomorphaf  sp. 
Determined  by  A.  B.  Oahan. 
One  male,  Antigua,  July  (Stoner). 

Cleonymidae 
Euchrysia  buscki  Ashm. 
One  female.    Antigua,  July   (Stoner).     Determined  by  A.  B. 
Gahan. 

Eurytomidae 
Decatomidea  pMidicornis  Ashm. 
Two  males  that  presumably  belong  to  this  species. 
Antigua,  July  (Stoner). 

Eucharidae 
Kapala  sp. 
One  male  that  appears  to  be  a  new  species  was  taken  on  Barba- 
dos, May  (Stoner). 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

Chalcididae 

Brachymeria  ovata  Say- 
Three  females.     Antigua,  July  (Stoner). 

Brachymeria  robusta  Cress. 
One  male  and  one  female.     Barbados,  May,  June  (Stoner). 

Spilochalcis  flavopicta  Cress. 
Three  females.     Antigua,  July  (Stoner). 

Spilochalcis  femorata  F. 
Two  females.     Barbados,  May  (Stoner). 

Vespoidea 
Scoliidas 

Compsomeris  dorsata  F. 
Six  females  and  ten  males.     Barbados,  Apr.  1914  (H.  A.  Bal- 
lou) ;  May,  June,  July  (Stoner) ;  St.  Kitts,  Aug.  15,  1913   (Agr. 
Supt.). 

Tiphia  nitida  Sm. 
One  female,  two  males.     Spencers,  Barbados,  July  1911,  June 
1913,  (Evely). 

Psammocharidae 
Psammochares  (Pompiloides)  coruscus  var.  juxtus  Cress. 
Female,  Antigua,  July  14-18. 

Psammochares  (Pompiloides)  subargenteus  Cress. 
Antigua,  July  (Stoner). 

Psammochares  (Pycnopompilus)  mundiformis  Roh. 
Male,  Antigua,  July  8,  (L.  Stoner). 

Pepsis  sanguigutta  Christ. 
Male,  Antigua,  June  (D.  Stoner). 

Eumenidae 

Odynerus  (Ancistrocerus)  n.  sp. 
Female.     Sandhurst,  Nov.  22,  1905. 

Odynerus  (Pachodynerus)  grenadensis  Ashm. 
Female.     Sandhurst,  Nov.  20,  1905. 

Vespidae 

Polistes  crinitus  Felton. 
Females,  Antigua,  July  1,  8,  1918  (L.  Stoner,  Stoner).     Deter- 
mined by  S.  A.  Rohwer. 


HYMENOPTERA  OF  BARBADOS  AND  ANTIGUA      11 

Polistes  cincta  Le  P. 
Females,  Barbados,  May  16-18  (D.  &  L.  Stoner).     Determined 
by  S.  A.  Rohwer. 

Sphecoibea 
Sphecidae 
Chlorion  (Ammobia)  ichneumoneum  L. 
Male,  Antigua,  July  (L.  Stoner). 

Notogonidea  ignipennis  Sm. 
Male,  Barbados,  June  (L.  Stoner). 

Apoidea 
Halictidae 
Halictiis  (Chloralhtus)  sp. 
Female  and  two  males,  Antigua,  July  (L.  Stoner). 

Megachilidae 
Megaokile  flavitarsata  Sm.  var. 
Male,  Antigua,  July  15-18  (D.  Stoner).    Appears  to  be  a  variety 
characterized  by  having  black  mid  and  hind-femora  and  tibiae 
instead  of  having  those  parts  rufotestaceous. 
MegachUe  concinna  Sm.  ? 
Male,  Barbados,  May  15-18  (D.  Stoner). 

Xylocopidae 

Xylocopa  fimbriata  L. 
Female,  Barbados,  June  (L.  Stoner). 

Euglossidae 
Centris  versicolor  F.  race  or  var. 
Female  and  male,  Barbados,  June  (L.  Stoner). 

Apidae 
Apis  mellifera  L. 
Workers,  Antigua  and  Barbados  (Stoner). 


TIPULIDiE  COLLECTED  BY  THE  UNIVERSITY 

OF  IOWA  FIJI-NEW  ZEALAND 

EXPEDITION 

Charles  P.  Alexander 

Amherst,  Massachusetts 

The  crane-flies  collected  by  the  1922  Expedition  of  the  University 
of  Iowa  to  Fiji  and  New  Zealand  have  been  submitted  to  the  writer 
for  determination  through  the  kindness  of  Professor  Dayton  Stoner. 
The  specimens,  including  the  type  of  Limonia  stoneri,  have  been 
returned  to  the  University  of  Iowa.  For  convenience  of  treatment, 
the  fauna  of  Fiji  is  considered  separately  from  that  of  New 
Zealand,  since  there  is  no  relation  between  the  two. 

FIJI 

The  crane-flies  of  the  Fiji  Islands  are  still  imperfectly  known, 
the  only  published  papers  upon  them  being  two  by  the  writer.1 
The  fauna  shows  a  marked  endemieism  though  clearly  derived  from 
the  larger  land  masses  lying  directly  to  the  eastward. 

The  present  collection  included  three  species  of  the  tribe  Limon- 
iini,  a  group  which  is  extremely  abundant  in  number  of  species 
throughout  the  Oriental  and  Australasian  Regions. 

Genus  Dicranomyia  Stephens 
1829.     Dicranomyia  Stephens;  Cat.  Brit.  Ins.,  2:  243. 

Dicranomyia  illingworthi  Alexander 
1914.     Dicranomyia  illingworthi  Alexander,  Ann.  Ent.  Soc.  Amer.,  7:  239- 
240. 

This  species  was  described  from  material  taken  at  Nadi  by  Dr. 
James  F.  Illingworth.  The  present  collection  includes  three  spec- 
imens (1  $ ,  2  $  $  )  labelled  ''Fiji,  June  1922."  The  species  has 
more  recently  2  been  recorded  from  North  Queensland. 

i  Alexander,  Charles  P.  On  a  collection  of  crane-flies  (Tipulidae  Diptera) 
from  the  Fiji  Islands.  Ann.  Ent.  Soc.  America,  7:  239-246,  pis.  34-35;  1914; 
New  or  little  known  Tipulidae  (Diptera).  — VII.  Australasian  Species.  Ann. 
Mag.  Nat.  Hist.,  (9)   8:546-563;   1921. 

2  Alexander,  Charles  P.  New  or  little-known  Australian  Crane-flies  (Tip- 
ulidae, Diptera).     Proc.  Roy.  Soc.  Queensland,  32:  92-109;  1920. 

12 


TIPULIDJE  OF  FIJI  AND  NEW  ZEALAND  13 

Subgenus  Thrypticomyia  Skuse 

1889.     Thrypticomyia  Skuse;  Proe.  Linn.  Soc.  N.S.W.   (2)  4:  774. 

Dicranomyia   (Thrypticomyia)  subsaltens  Alexander 
1922.     Dicranomyia    (Thrypticomyia)    subsaltens    Alexander;    Ann.    Mag. 
Nat.  Hist.,  (9)  10: 

This  is  the  species  that  was  earlier  recorded  as  Dicranomyia 
salt  ens  (Doleschall),  from  material  taken  by  Dr.  Illingworth  at 
Nadi.  Later  material  was  received  from  Lautoka,  collected  by 
Messrs.  Greenwood  and  Veitch.  A  study  of  this  material  revealed 
the  specific  distinctness  of  the  species  from  2>.  (T.)  apicalis 
(Wiedemann)  which  is  now  known  to  be  distinct  from  D.  (Euglo- 
china)  saltens  (Doleschall)  of  the  East  Indian  Islands.  The  pres- 
ent collection  includes  a  $ ,  Walu  Bay,  Suva,  Viti  Levu,  June  13, 
1922. 

Genus  Limonia  Meigen 

1803.     Limonia  Meigen;  Illiger's  Mag.,  2:  262. 

The  center  of  distribution  of  the  great  genus  Limonia  appears 
to  be  the  palaeotropical  region,  from  whence  it  has  spread  to 
almost  all  of  the  major  land  masses  of  the  world.  In  the  present 
collection,  a  single  species  was  included  which  is  herein  considered 
as  being  undescribed. 

Limonia  stoneri,  sp.n. 

General  coloration  light  yellow;  pronotum  darkened  medially;  head  brown- 
ish black;  legs  yellow,  the  tips  of  the  femora  conspicuously  blackened;  ab- 
dominal tergites  obscure  brownish  yellow,  each  with  a  transverse  central  band 
of  dark  brown,  sternites  dark  brown. 

F&male.  —  Length   about   10  mm.     Described  from  an  alcoholic  specimen. 

Eostrum  brown;  palpi  dark  brown.  Antennae  with  the  scape  dark  brown; 
flagellum  paler  brown,  the  basal  segments  with  the  proximal  portion  yellowish. 
Head  brownish  black. 

Pronotum  yellow,  dark  brownish  medially.  Mesonotal  praeecutum  and 
scutum  yellowish,  the  former  very  narrowly  and  indistinctly  darkened  anter- 
iorly; scutellum  light  yellow  with  a  small  brown  spot  on  either  side  of  the 
median  line  at  the  base;  postnotum  yellow,  the  basal  median  region  more  or 
less  darkened.  Pleura  yellow.  Halteres  yellow,  the  knobs  dark  brown.  Legs; 
with  the  coxae  and  trochanters  yellow;  femora  yellow,  the  tips  rather  broadly 
and  conspicuously  blackened;  tibiae  obscure  yellow,  the  tips  very  narrowly 
darkened ;  tarsi  obscure  yellow.  Wings  badly  injured  and  their  characters 
can  be  defined  in  general  terms  only;  general  coloration  pale  brown,  the  costal 
region  more  yellowish ;  stigma  relatively  small,  oval,  dark  brown ;  veins  dark 
brown,  those  in  the  costal  region  more  yellowish.  Venation:  Sc  long,  Sci 
alone  a  little  longer  than  the  distance  between  the  tip  of  Sci  and  the  proximal 
end  of  Bs. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

Abdominal  tergites  obscure  brownish  yellow,  with  a  transverse  central 
band  of  dark  brown  across  each  segment;  the  pale  apex  of  each  segment  is 
a  little  broader  than  the  similarly  colored  apex;  subterminal  segments  light 
yellow;  sternites  dark  brown,  the  subterminal  segments  yellow.  Ovipositor 
with  the  tergal  valves  relatively  short  and  slender,  the  longer,  straight  sternal 
valves  blackened  at  base. 

Habitat.  —  Fiji  (Viti  Levu). 

Holotype,   9  ,  Walu  Bay,  Suva,  June  13,  1922  (Dayton  Stoner). 
The  type  of  this  interesting  species  is  in  the  University  of  Iowa. 
It  is  named  in  honor  of  the  collector,  Professor  Dayton  Stoner. 

NEW  ZEALAND 

The  crane-fly  fauna  of  New  Zealand  is  now  known  to  be  an 
extremely  rich  and  varied  one.  At  the  time  of  the  signing  of  the 
armistice  in  1918,  the  total  number  of  species  of  Tipuloidea 
described  from  New  Zealand  was  less  than  fifty.  Since  that  time 
there  has  been  great  activity  among  collectors  and  a  very  con- 
siderable number  of  additional  species  have  been  described,  chiefly 
by  Edwards  and  the  writer.  The  number  of  species  now  known 
from  New  Zealand  is  not  less  than  350  and  the  number  will  be  still 
further  augmented  with  additional  collections.  The  present  col- 
lection includes  only  9  species  but  this  must  be  considered  as  being 
a  fair  representation  of  the  fauna  on  the  wing  at  the  time  the 
collections  were  made.  The  published  records  for  Auckland  are 
very  poor  and  the  present  list  adds  several  species  to  the  list  from 
this  Province. 

Genus  Dicranomyia  Stephens 

Dicranomyia  wgrotans  Edwards 
1923.     Dicranomyia  wgrotans  Edwards;   Trans.  N.Z.  Inst.,  for  1921,  54: 
Two    S  $    from  Kauri  Gully,  Auckland,  July  18,  1922.     The 

species  has  a  very  wide  range  throughout  both  islands  of  New 

Zealand. 

Dicranomyia  vicarians  (Schiner) 
1868.     dLimnobia  vicarians  Schiner;  Novara  Reise,  Dipt.,  p.  46. 
This  is  one  of  the  commonest  and  best-known  crane-flies  in  New 

Zealand,  ranging  over  most  of  both  islands.     The  present  collection 

includes  a  specimen  from  * '  The  Domain, ' '  Auckland,  July  14,  1922. 

Dicranomyia  nephelodes  Alexander 
1922.     Dicranomyia  nephelodes  Alexander;  Ann.  Mag.  Nat.  Hist.,   (9)   10: 

84-85. 


TIPVhIDM  OF  FIJI  AND  NEW  ZEALAND  15 

This  recently  described  crane-fly  has  been  known  only  from  the 
vicinity  of  Ohakune,  at  the  foot  of  Mount  Ruapehu,  where  the 
types  were  taken  by  Mr.  Harris.  The  present  collection  includes 
material  from  Kauri  Gully,  Auckland,  taken  July  15-18,  1922. 

Dicranomyia  cubitalis  Edwards 
1923.    Dicranomyia  cubitalis  Edwards;  Trans.  N.Z.  Inst.,  for  1921;  54: 
This  is  another  widely  distributed  species,  occurring  in  both 

islands.    The   present   collection   includes  material   from   Kauri 

Gully,  Auckland,  July  15,  1922. 

Genus  Molophilus  Curtis 

1833.     MolophUus  Curtis;  Brit.  Ent.,  p.  444. 

The  genus  Molophilus  is  one  of  the  largest  genera  in  New  Zeal- 
and, where  the  number  of  known  species  is  not  far  from  fifty. 

Molophilus  multicinctus  Edwards 
1923.    Molophilus  multicinctus  Edwards;  Trans.,  N.Z.  Inst.,  for  1921;  54: 
A  specimen  from  Helensville,  Auckland,  July  17,  1922.    The 
fly  has  a  wide  range  in  both  islands. 

Molophilus  aucklandicus  Alexander 
1923.    Molophilus  aucMandicus  Alexander;  Ann.  Mag.  Nat.  Hist.,  (9)  10: 
This  species  was  described  from  Auckland,  based  upon  material 

taken  by  Mr.  Harris.    The  present  collection  includes  a   $   from 

Kauri  Gully,  Auckland,  July  18,  1922. 

Genus  Amphineurus  Skuse 
1889.    Amphineurus  Skuse;  Proc.  Linn.  Soe.  N.S.W.,  (2)  4:  802. 
This  large  and  important  genus  reaches  its  maximum  of  specific 

development  in  New  Zealand.       It  is  unquestionably   allied  to 

Ormosia  of  the  Northern  Hemisphere  but  must  be  considered  as 

being  distinct. 

Amphineurus  perdecorus  Edwards 
1923.    Amphineurus  perdecorus  Edwards;  Trans.  N.Z.  Inst.,  for  1921,  54: 
One  #  from  Kauri  Gully,  Auckland,  July  18,  1922.     This  rather 

uncommon  crane-fly  occurs  in  the  North  Island. 

Amphineurus,  sp.,  near  gracilisentis  Alexander 
1922.    Amphineurus  gracilisentis  Alexander;   Ann.   Mag.   Nat.   Hist.,    (9) 
10:  563. 

A  large  female  specimen  from  Kauri  Gully,  Auckland,  taken 


16  IOWA  STUDIES  IN  NATUEAL  HISTORY 

July  15,  1922,  may  belong  here.     It  is  not  possible  to  determine 
isolated  females  in  many  of  the  larger  genera  of  Tipulidas. 

Genus  Trimicra  Osten  Sacken 
1861.  Trimicra  Osten  Sacken;  Proe.  Acad.  Nat.  Sci.  Phila.,  p.  290. 
The  genus  Trimicra  occurs  on  virtually  all  of  the  continents  and 
many  of  the  oceanic  islands.  There  is  still  much  doubt  as  to  how 
many  species  are  involved  but  the  present  evidence  seems  to  indi- 
cate that  virtually  all  of  the  many  described  species  are  synony- 
mous with  the  first-described  T.  pilipes  (Fabricius).  Considerable 
variation  in  the  length  of  the  2nd  anal  vein  in  these  various  so- 
called  species  makes  it  necessary  to  investigate  certain  of  them 
more  closely,  since  this  character  of  length  of  the  2nd  anal  vein 
has  been  used  as  a  generic  and  subgeneric  criterion  in  other  groups 
of  the  Eriopterini. 

Trimicra  inconstans  Alexander 

1922.  Trimicra  inconstans  Alexander;  Ann.  Mag.  Nat.  Hist.,  (9)  9:  148, 
149. 

Several  specimens  from  Helensville,  July  17,  1922;  one  $  from 
Kotorua,  vicinity  of  hot  springs,  July  31,  1922.  This  latter  has 
been  recorded  by  Professor  Stoner  3  as  feeding  on  the  algae  grow- 
ing on  the  hot  sand  in  the  near  vicinity  of  the  hot,  bubbling  springs. 

3  Stoner,  Dayton.  Insects  taken  at  Hot  Springs,  New  Zealand.  Ent.  News, 
34:  88-90;  1923. 


PHOTOGRAPHIC  PRACTICE  FOR  FIELD 
GEOLOGISTS 

Chester  K.  Wentworth 

University  of  Iowa 

INTRODUCTION 

Foreword 

In  preparing  the  following  paper  the  writer  has  received  sug- 
gestions and  criticism  from  a  number  of  geologists  and  students  of 
photography.  Considerable  difference  of  opinion  existed  among 
those  who  read  the  preliminary  manuscript  in  regard  to  the  desired 
emphasis  on  different  points  and  on  the  length  of  treatment  but  in 
general  suggestions  made  were  followed  in  revising  the  paper. 
Especial  thanks  are  due  to  R.  B.  Wylie,  J.  J.  Runner,  and  B.  T. 
Apfel  of  the  University  of  Iowa,  to  F.  E.  Wright  of  the  Geophysical 
Laboratory  at  Washington,  and  to  E.  A.  Shuster  of  the  Photograph- 
ic Laboratory  of  the  U.  S.  Geological  Survey  for  helpful  comments 
and  criticism. 

Purpose  of  Geological  Photography 

There  are  two  general  classes  of  photography :  the  one,  which  may 
be  designated  as  artistic  photography,  being  practiced  primarily  for 
esthetic  purposes;  the  other,  known  as  record  photography,  being 
devoted  to  practical  ends  in  the  pure  and  applied  sciences.  Photo- 
graphy as  practiced  by  geologists  belongs  essentially  to  the  latter 
class  and  it  is  in  the  main  from  the  practical  standpoint  that  it  is 
considered  here.  Photographs  are  used  in  the  presentation  of  the 
facts  and  principles  of  geology.  These  may  be  presented  as  a  part 
of  an  original  contribution  to  the  science  or  they  may  be  presented 
as  parts  of  a  treatise  representing  current  knowledge  in  one  or  all 
branches  of  the  subject.  In  either  case  the  photographs  may  ac- 
company a  printed  book  or  paper  or  may  be  copied  in  the  form  of 
lantern-slides  or  prints  to  illustrate  an  oral  discourse.  More  fre- 
quently than  otherwise  the  use  of  photographs  renders  the  pre- 
sentation not  only  more  pleasing  but  also  effects  a  considerable 

17 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

economy  of  time  and  space.  In  the  case  of  most  sorts  of  bare  facts 
the  effectiveness  of  presentation  is  probably  greatest  when  the 
phenomena  are  actually  seen  by  the  person  who  is  to  be  informed. 
Next  in  order  is  the  viewing  of  a  good  picture  and  third  and  least 
effective  as  a  single  means  is  the  text  description.  A  combination 
of  the  latter  two  is  probably  more  effective  than  either  alone  and 
next  best  to  the  combination  of  observation  and  discussion  of  the 
phenomena  at  first  hand.  In  addition  to  their  use  as  single  per- 
manent records  photographs  are  sometimes  of  great  value  to  show 
progressive  changes  such  as  those  which  take  place  in  vegetation, 
processes  of  erosion  or  deposition  and  the  like  and  are  then  taken  in 
series. 

Importance  to  Field  Geologists 

The  importance  of  a  knowledge  of  photography  to  field  geologists 
is  apparent  when  it  is  recognized  that,  except  for  the  most  general 
views  of  topographic  features  and  for  photographs  of  common 
features  which  may  be  recognized  by  inspection,  the  great  bulk  of 
photographs  of  value  in  geologic  investigations  or  teaching  must 
be  taken  by  the  geologist  most  familiar  with  the  phenomena  to  be 
illustrated.  It  is  the  exception  rather  than  the  rule  when  it  is 
possible  for  the  geologist  to  designate  the  features  of  importance 
and  have  them  photographed  by  a  professional  photographer. 
Not  only  must  the  field  investigator  himself  determine  the  features 
of  which  pictures  are  to  be  made  but  he  must  decide  upon  the  point 
of  view,  the  arrangement  if  they  are  movable,  and  the  other  condi- 
tions so  far  as  they  may  be  controlled  and  he  alone  is  able  satis- 
factorily to  decide  upon  the  fitness  of  the  resulting  pictures.  It  is 
true  that  that  part  of  the  picture  making  which  may  be  called  the 
dark-room  technique  may  be  advantageously  turned  over  to  others. 
It  is  very  desirable,  however,  that  the  geologist  be  versed  in  the 
general  principles  of  developing  and  fixing  of  negatives  and  of 
making  prints  for  he  can  then  most  intelligently  recognize  the 
sources  of  imperfection  in  resulting  pictures  and  improve  his  own 
technique  or  criticise  that  of  the  dark-room  as  the  ease  may  be. 
Consideration  of  the  dark-room  technique  is  beyond  the  scope  of 
this  paper  and  moreover  is  adequately  treated  in  an  extensive 
literature  since  that  of  use  to  geologists  is  no  different  from  that  of 
other  branches  of  record  photography. 

In  the  case  of  field  procedures,  however,  there  seems  to  be  room 


PHOTOGRAPHIC  PRACTICE  19 

for  description  of  the  methods  and  equipment  which  have  been 
found  most  useful.  Much  that  appears  below  is  applicable  to 
other  branches  of  out-of-door  record  work  such  as  that  done  by 
students  of  botany,  zoology  and  other  branches  of  natural  science. 

Diversity  of  Photographic  Conditions  in  the  Field 

If  field  photography  may  be  said  to  have  any  essential  peculiarity 
it  is  the  extreme  diversity  of  conditions  which  are  confronted. 
These  include  variations  of  sunlight  due  to  differences  of  time  of 
day  and  condition  of  the  atmosphere  as  well  as  those  due  to  differ- 
ences in  latitude  and  season  of  the  year.  Subjects  vary  enormously 
in  their  colors,  inherent  contrasts  and  brightness.  Many  of  these 
are  quite  fixed  and  immovable  and  are  in  positions  none  too  favor- 
able for  successful  photography.  Even  in  those  cases  where  the 
subjects  might  more  advantageously  be  photographed  under  better 
conditions  of  light  or  at  another  time  of  day  it  is  not  commonly 
practicable  for  the  field  geologist  to  wait  for  the  improved  condi- 
tions. The  observation,  note-taking,  collecting  and  other  oper- 
ations of  field  investigation  are  so  onerous  that  most  commonly  the 
geologist  will  not  have  occasion  to  return  to  the  exact  spot  and 
should  be  prepared  to  secure  the  best  possible  results  in  photo- 
graphy at  the  time  he  first  studies  any  given  feature. 

Limitations  in  Equipment  1 

The  geologist's  task  is  made  more  exacting  by  the  fact  that  he  can 
usually  carry  but  a  limited  amount  of  equipment,  a  considerable 
part  of  which  is  for  other  than  photographic  purposes.  With  the 
very  restricted  amount  of  photographic  equipment  at  hand  he 
must  photograph  a  wide  range  of  subjects  under  conditions  far 
more  diverse  than  those  met  by  most  commercial  photographers. 
It  is  clear  that  success  in  this  work  demands  considerable  know- 
ledge of  ^photographic  principles  and  careful  choice  of  equipment 
as  well  as  painstaking  attention  at  all  times  to  the  technical  de- 
tails. 

EQUIPMENT  FOR  FIELD  USE 
The  Camera 

The  writer  does  not  propose  to  discuss  the  relative  merits  of 

many  different  models  of  domestic  and  foreign  hand  cameras  which 

1 1t  has  seemed  best  in  the  present  paper  to  treat  the   subject  of   field 


20  IOWA  STUDIES  IN  NATUKAL  HISTORY 

are  available.  It  will  be  sufficient  to  point  out  the  inherent  ad- 
vantages and  disadvantages  of  a  few  types  as  related  to  different 
sorts  of  field  photography.  Cameras  of  interest  to  field  geologists 
may  be  grouped  in  four  classes.     These  are 

1.  Eoll  film  folding"  cameras 

2.  Plate  back  folding  cameras 

3.  View  cameras  with  long  extension 

4.  Reflecting  cameras 

Perhaps  the  first  choice  to  be  made  is  that  between  roll  film 
cameras  and  plate-film  pack  cameras.  The  former  are  unquestion- 
ably more  convenient  to  manipulate  and  carry  and  the  roll  films 
are  more  readily  obtained  in  small  towns  than  plates,  cut  films  or 
film  packs.  The  roll  films  are  far  lighter  per  exposure  than  plates 
or  cut  films  and  the  roll  film  camera  is  somewhat  less  bulky  than 
the  plate  camera  of  the  same  nominal  size.  For  the  geologist  who 
wishes  to  do  critical  work  in  both  detail  and  distant  views  the  plate 
camera  has  certain  distinct  advantages  among  which  are  the  use 
of  the  ground  glass  for  focusing  and  composition,  the  use  of  various 
grades  of  films  or  plates  such  as  those  of  varying  speed,  contrast 
or  color  sensitivity. 

The  ultimate  choice  between  the  roll  film  and  plate  cameras 
depends  on  the  personal  attitude  of  the  user  toward  photography. 
Not  all  aspects  of  field  technique  will  be  accorded  equal  attention 
by  different  persons  and  by  some  photography  will  be  treated  as 
a  necessary  part  of  the  field  work  but  not  as  an  avocation  as  it 
will  by  others.  For  the  geologist  who  wishes  to  cope  with  the 
unusual  and  difficult  subjects  and  to  use  different  grades  of  cut 
films  and  a  convertible  lens  the  plate  camera  is  essential.  On  the 
other  hand,  using  the  same  care  on  the  details,  negatives  of  equal 
quality  can  probably  be  made  from  four  out  of  five  subjects  with 
the  roll  film  type  of  folding  camera.  The  scope  of  this  sort  may 
be  greatly  increased  by  the  use  of  auxiliary  lenses  as  previously 
described  by  the  writer.1 

There  are  opportunities  for  a  considerable  range  of  choice  in 
selecting  a  roll  film  camera  and  it  is  sufficient  to  point  out  that 
a  brilliant  view  finder,  rising  and  falling  front,  substantial  bed 

photography  from  the  standpoint  of  travel  on  foot.  Travel  by  automobile 
where  it  is  practicable  permits  transportation  of  more  elaborate  equipment 
but  the  same  principles  hold  in  the  field  practice. 

i  Wentworth,  C.  K.  (Adapting  a  Short  Bellows,  Roll  Film  Camera  for 
Detail  Work.)     Journal  of  Geology,  Vol.  XXX,  pp.  158-161,  1922. 


PHOTOGRAPHIC  PRACTICE  21 

and  focusing  mechanism  and  a  dependable  shutter  are  the  impor- 
tant features.  There  is  an  even  greater  diversity  of  type  in  plate 
cameras.  Box  cameras  of  the  Corona  type  are  very  useful  for  all 
kinds  of  out  of  door  work  close  to  headquarters  or  when  working 
by  automobile  but  are,  even  size  for  size,  rather  bulkier  than  other 
types  and  are  not  so  convenient  for  foot  travel.  There  are  a 
number  of  small  plate-back  folding  cameras,  especially  in  the 
foreign  makes,  which  have  longer  bellows  extension  to  facilitate 
short  range  focusing  and  the  use  of  single  components  of  con- 
vertible lenses.  These  are  very  useful  in  combining  portability 
with  the  advantages  of  ground  glass  composition  and  use  of  various 
grades  of  plates  or  films. 

Reflecting  cameras  of  which  the  Graflex  may  be  taken  as  a  type 
are  unexcelled  for  photographing  moving  objects  or  those  that 
must  be  caught  in  certain  transitory  positions.  Some  of  them  are 
fitted  with  long  bellows  extension  and  other  adjustments  and  when 
used  with  a  tripod  are  equally  satisfactory  for  still  pictures.  The 
mechanism  throughout  is  usually  high  grade  and  for  general 
purposes  they  must  rank  high.  At  the  same  time  they  are  nec- 
essarily heavy  and  bulky  and  will  hardly  be  chosen  by  the  geologist 
who  must  carry  his  equipment  on  foot.  For  most  geologic  pictures 
speed  is  not  essential  and  the  shallowness  of  definition  forced  by 
the  use  of  wide  apertures  is  so  objectionable  as  to  be  justified  only 
where  the  speed  is  absolutely  necessary.  In  all  other  cases  the 
extra  weight  of  the  Graflex  which  is  aimed  mainly  at  this  one 
object  serves  no  purpose. 

In  choosing  a  camera  for  every  day  field  use  perhaps  the  first 
question  to  be  considered  is  size.  Probably  the  bulk  of  pictures 
taken  for  geologic  illustration  are  made  with  cameras  of  the 
34"x4;£"  or  3i"x5£"  sizes.  The  writer  believes  that  one  or  the 
other  of  these  sizes  will  be  found  more  satisfactory  than  any  larger 
or  smaller  sizes.  Much  has  been  written  on  the  general  plan  of 
making  sharply  defined  small  negatives  with  a  high  grade  anastig- 
mat  lens  and  enlarging  the  image  in  printing.  Theoretically  the 
plan  has  much  to  commend  it.  Equipment  is  much  lighter  and 
less  bulky,  the  short  focus  lens  has  greater  relative  depth,  film 
is  less  expensive  and  easier  to  store  than  in  the  larger  sizes. 
Satisfactory  enlargements  for  ordinary  pictorial  purposes  can 
undoubtedly  be  made  from  small  negatives  for  purposes  of  scien- 
tific record.     However  there   are  so   many   sources   of   defective 


22  IOWA  STUDIES  IN  NATUKAL  HISTORY 

definition  or  of  other  flaws  in  the  negative  that  the  writer  believes 
in  the  long  run  the  average  negative  is  none  too  good  and  should 
be  large  enough  to  give  by  contact  printing  an  image  of  sufficient 
size  to  serve  as  a  moderate  sized  illustration  in  a  published  paper 
or  large  enough  to  serve  as  a  lantern  slide  for  projection.  The 
labor  and  expense  of  printing  by  enlargement  is  considerably 
greater  than  that  by  contact  and  the  writer  does  not  know  of  a 
single  geologist  who  possesses  an  extended  series  of  good  field 
pictures  made  wholly  by  enlargement  from  the  negatives. 

The  Lens 

There  is  a  wide  range  of  choice  in  lenses.  A  lens  at  least  as  good 
as  the  widely  known  Rapid  Rectilinear  is  essential.  For  a  few 
geologic  subjects  greater  speed  than  is  given  by  the  f/8  aperture 
is  needed.  It  is  a  source  of  much  satisfaction  to  have  a  high  grade 
anastigmat  lens  for  these  occasional  needs  but  the  writer  believes 
the  desirability  of  a  fast  lens  can  be  greatly  exaggerated.  It 
seems  to  him  profoundly  true  that  a  fine  series  of  photographs 
illustrating  geologic  features  reflects  patience  and  skill  on  the 
part  of  the  photographer  to  an  enormously  greater  degree  than 
it  does  the  quality  of  the  lens  he  used.  From  inspection  of  most 
such  pictures  it  is  quite  impossible  for  anyone  to  tell  with  what 
sort  of  lens  they  were  taken  and  compliments  on  ones  lens  based 
on  admiration  of  good  photographs  of  the  features  ordinarily  taken 
by  geologists  commonly  indicate  only  ignorance  of  the  most  ele- 
mentary photographic  principles.  By  the  foregoing  statement  the 
writer  has  no  intention  of  appearing  scornful  toward  high  grade 
lenses  but  merely  wishes  to  emphasize  the  view  that  understanding 
of  the  equipment  the  operator  has  in  hand  is  of  vastly  more  im- 
portance than  the  price  he  paid  for  it. 

There  is  so  much  popular  misunderstanding  on  the  subject  of 
lenses  that  a  few  words  on  elementary  principles  will  not  be  amiss 
at  this  point.  A  simple  meniscus  lens  such  as  that  of  a  small 
pocket  magnifier  has  six  principal  types  of  defect  or  departure 
from  perfect  definition.  There  are  spherical  aberration,  chromatic 
aberration,  distortion,  curvature  of  field,  astigmatism  and  coma. 
These  may  be  briefly  defined  as  follows: 

Spherical  aberration  —  Caused  by  the  convergence  of  rays  pass- 
ing through  the  outer  parts  of  the  lens  at  different  distances  from 
those  passing  through  the  central  parts. 


PHOTOGRAPHIC  PRACTICE  23 

Chromatic  aberration  —  Caused  by  the  convergence  at  different 
distances  of  rays  of  different  colors,  hence  of  different  wave 
lengths. 

Distortion  —  Caused  by  convergence  of  rays  from  objects  not  on 
the  lens  axis  at  distances  from  the  axis  not  strictly  proportional 
to  the  distances  of  the  objects  from  the  axis.  Straight  lines  not 
passing  through  the  center  of  the  field  become  slightly  curved  in 
the  image. 

Curvature  of  field  —  Consists  in  the  convergence  of  rays  from 
outer  points  of  a  plane  field  at  different  distances  from  those  from 
the  central  parts,  thus  making  the  focal  locus  a  curved  surface 
symmetrical  to  the  lens  axis  rather  than  a  plane. 

Astigmatism  —  Consists  in  the  establishment  at  different  dis- 
tances of  images  of  lines  radial  to  the  lens  and  those  tangential 
to  the  lens. 

Coma  —  Consists  of  a  blur  produced  by  lateral  spherical  aber- 
ration of  rays  passing  obliquely  to  the  axis  of  the  lens. 

In  high  grade  lenses  these  defects  are  greatly  reduced  in  amount 
by  the  combination  of  simple  lenses  of  different  forms  and  made 
of  glass  of  different  refractive  and  dispersive  qualities  but  they 
are  never  completely  eliminated.  All  these  defects  are  much 
reduced  in  actual  practice  by  using  small  apertures. 

The  six  defects  mentioned  above  are  so  interrelated  that  an 
attempt  to  achieve  partial  perfection  by  the  elimination  of  any 
one  usually  results  in  increasing  one  or  more  of  the  others.  For 
any  lens  the  so-called  speed  (a  most  misleading  term)  or  relative 
aperture  is  the  ratio  between  the  largest  aperture  at  which  the 
lens  will  give  satisfactory  definition  and  its  focal  length.  Satis- 
factory definition  is  commonly  considered  to  exist  when  the  image 
of  no  point  is  dispersed  by  the  combined  defects  over  a  circle 
of  greater  than  1/200  inch  in  diameter.  Most  lenses  are  so 
mounted  that  no  larger  apertures  may  be  used  and  the  "speed" 
is  thus  a  statement  of  the  largest  working  aperture,  There  is 
no  practical  difference  in  the  rate  at  which  light  passes  through 
the  glass  of  different  lenses  nor  in  the  amount  of  light  transmitted 
by  an  aperture  of  unit  size. 

Depth  of  definition  is  not  an  inherent  quality  of  a  lens.  It  is 
a  variable  condition  controlled  by  the  aperture  in  use  and  the 
focus  of  the  lens  and  is  the  same  for  all  lenses  of  the  same  focus 
and  at  the  same  aperture.     The  very  great  and  very  useful  depth 


24  IOWA  STUDIES  IN  NATURAL  HISTORY 

of  definition  of  fixed  focus  cameras  of  the  Brownie  type  is  a  nec- 
essary consequence  of  their  small  maximum  apertures  and  relatively 
short  focus  and  may  be  duplicated  by  using  proper  adjustments 
on  any  small  hand  camera. 

A  convertible  lens  is  one  so  designed  that  one  of  the  two  com- 
ponents may  be  used  alone.  In  some  lenses  the  two  components 
are  identical  and  either  may  be  used  with  the  same  result ;  in  others 
known  as  triple  convertible  the  two  components  are  of  different 
focal  lengths  and  thus  by  using  either  alone  or  the  two  together 
offer  three  focal  lengths.  The  advantage  of  the  choice  of  focal 
lengths  is  very  great  in  controlling  the  size  of  the  image  when  the 
viewpoint  is  fixed  by  topographic  or  other  conditions.  The  longer 
focal  lengths  give  larger  images  from  a  fixed  viewpoint  and  have 
the  quality  of  giving  less  pronounced  perspective  than  the  shorter 
focal  lengths. 

Very  short  exposures  are  not  essential  for  most  geologic  sub- 
jects since  these  are  stationary  and  excessively  large  apertures  are 
undesirable  because  of  the  shallowness  of  definition.  The  writer 
feels  that  a  lens  of  f/6.3  aperture  and  possessed  of  low  distortion 
and  curvature  of  field  is  as  good  as  any  for  field  use. 

An  excellent  description  of  many  of  the  well  known  types  of 
lenses  is  contained  in  the  article  on  Photography  in  the  Encyclo- 
pedia Britannica,  11th  Edition. 

Closely  related  to  the  question  of  lenses  is  that  of  shutters. 
Lenses  of  larger  apertures  than  f/8  are  commonly  fitted  with 
shutters  in  which  a  spring  previously  set  is  released  by  the  trigger 
whereas  those  of  f/8  and  less,  commonly  have  the  energy  furnished 
and  release  effected  by  the  same  movement  of  the  hand.  When 
the  former  type  is  used  in  the  field  the  writer  believes  quite  as 
much  benefit  is  derived  from  the  advantage  of  the  compound  shut- 
ter as  from  the  superior  lens.  The  latter  type  of  shutter  rarely 
has  actually  the  speeds  nor  the  range  indicated,  the  high  speeds 
being  slower  and  the  lower  speeds  faster  than  those  shown.  The 
former  type,  if  in  good  condition,  is  far  more  likely  to  show  close 
agreement  between  indicated  and  actual  speeds  and  furthermore 
is  susceptible  of  more  accurate  adjustment.  The  focal  plane  shutter 
is  indispensible  for  cameras  of  the  Graflex  type  but  as  mentioned 
above  these  are  not  considered  to  be  so  convenient  for  general 
geologic  work. 

There  are  various  accessory  devices  which  have  been  developed 


PHOTOGRAPHIC  PRACTICE  25 

by  various  makers,  some  of  which  are  essential  and  others  of  less 
value.  The  rising  and  sliding  front  is  valuable  and  will  be  found 
on  most  cameras  having  other  necessary  features.  The  writer  has 
made  little  personal  use  of  the  autographic  features  since  he  prefers 
to  add  photographic  notes  to  others  constantly  made  in  the  field 
note  books  but  other  geologists  prize  the  feature  highly.  The 
range  finder  with  which  some  cameras  are  equipped  is  probably 
of  less  value  to  the  geologist  than  to  the  general  public  since  he 
probably  estimates  distances  with  considerable  accuracy  by  inspec- 
tion. The  same  may  be  said  of  a  level.  The  writer  finds  that 
sighting  on  the  horizon  or  comparison  with  the  vertical  lines  of 
trees  insures  reasonable  alignment  of  the  pictures  for  ordinary 
purposes.  The  use  of  a  precise  level  for  phototopographic  work  of 
any  sort  is  of  course  quite  another  matter. 

Plates  and  Films 

There  is  a  wide  variety  of  plates  and  films  of  various  makes 
available  at  the  present  time,  of  which  practically  all  may  be  re- 
garded as  of  excellent  quality.  Roll  films  and  film  packs  are  com- 
monly of  one  speed  and  orthochromatic  to  a  moderate  degree. 
Some  of  the  film  of  film  packs  appears  to  carry  a  slightly  thinner 
emulsion  than  the  roll  film  but  this  difference  is  of  relatively  small 
importance  on  most  subjects.  Glass  plates  in  all  the  standard 
sizes  may  be  had  in  a  number  of  speeds  and  degrees  of  contrast 
and  with  orthochromatic  and  panchromatic  color-sensitive  emul- 
sions. A  similar  variety  is  available  in  the  newer  cut  films  which 
are  extensively  used  by  many  commercial  and  amateur  photo- 
graphers. The  principal  advantage  of  the  cut  film  over  the  plates 
aside  from  the  obvious  reduction  of  weight  and  danger  of  break- 
ing is  that  in  the  film  halation  is  practically  negligible  due  to  the 
lesser  thickness  and  reduced  reflections. 

A  few  general  principles  may  be  noted  here.  Very  rapid  plates 
or  films  commonly  have  somewhat  coarser  grain  in  the  emulsion 
and  also  have  considerably  less  latitude.  The  slow  process  plates 
have  likewise  much  less  latitude.  Where  special  purpose  films  or 
plates  are  needed  they  serve  admirably  but  it  must  be  remembered 
that  in  many  instances  their  special  properties  have  been  secured 
at  the  sacrifice  of  some  other  feature.  Color-sensitive  plates  and 
films  have  revolutionized  the  photography  of  certain  objects  and 
will  undoubtedly  increase  in  use  in  the  future.     In  conjunction 


26  IOWA  STUDIES  IN  NATUBAL  HISTOKY 

with  the  proper  filters  they  permit  the  portrayal  of  any  object 
in  terms  of  a  small  part  of  the  total  light  reflected  from  it  and  that 
of  a  relatively  narrow  range  in  wave  length.  To  see  the  possibili- 
ties in  this  field  one  has  but  to  make  visual  examination  of  various 
natural  and  artificial  colored  objects  through  various  photographic 
filters.  Photography  in  natural  colors  is  made  possible  by  a 
number  of  processes  but  it  will  not  be  considered  in  the  present 
paper  for  two  reasons;  first,  because  the  writer  has  had  no  per- 
sonal experience  with  these  processes  and  second,  because  it  appears 
unlikely  that  it  will  be  used  to  any  considerable  extent  by  geologists 
in  their  professional  work  in  the  near  future. 

The  materials  to  be  used  will  have  been  in  part  determined  by 
the  choice  of  a  camera.  If  this  was  of  the  roll  film  type  there  is 
relatively  little  choice  to  be  made  in  the  matter  of  films.  In  many, 
one  might  say  most,  cases  it  is  desirable  for  the  geologist  to  secure 
a  goodly  supply  of  film  before  going  to  the  field  and  in  such 
instances  this  is  best  packed  in  foil  or  other  airtight  "tropical" 
container. 

If  a  plate  camera  is  used  and  many  photographs  are  to  be  taken 
incidental  to  long  daily  trips  the  film  pack  will  be  desirable  since 
the  weight  is  slight  in  comparison  to  that  of  either  plates  or  films 
in  separate  holders.  If  not  over  six  or  eight  exposures  are  made 
in  a  day  separate  holders  containing  cut  film  can  well  be  carried. 
In  this  case  some  may  be  of  ordinary  portrait  or  commercial  grade 
and  a  few  orthochromatic  or  panchromatic.  Orthochromatic  film 
is  being  increasingly  used  for  general  purpose  work  as  well  as  for 
special  subjects  and  the  writer  feels  that  it  might  profitably  be 
substituted  for  most  routine  field  work  with  plate  cameras.  The 
same  is,  of  course,  true  of  plates  with  similar  emulsion  but  it  is  un- 
likely that  many  geologists  will  prefer  the  plates  to  the  lighter  cut 
films.  Panchromatic  films  aside  from  being  slightly  slower  than 
other  grades  are  equally  useful  on  all  subjects  and  are  essential  if 
the  deeper  filters  such  as  red,  orange  and  green  are  to  be  used. 

Tripods  and  Supports 

Some  sort  of  tripod  is  essential  as  is  urged  by  the  writer  at  great 
length  elsewhere.  On  the  score  of  weight  the  tripod  is  always 
something  of  a  burden  and  there  seems  to  be  little  escape  from  this 
difficulty.  Many  different  sorts  of  tripods  have  been  devised  in 
America  and  abroad  with  object  of  securing  the  greatest  rigidity 


PHOTOGRAPHIC  PRACTICE  27 

with  the  least  weight.  From  this  standpoint  the  folding  wooden 
tripod  is  probably  the  best  but  it  is  less  convenient  and  more  bulky 
than  the  tubular  telescopic  metal  tripods.  The  latter  deteriorate 
in  stiffness  more  rapidly  than  the  wooden  tripods  in  the  course  of 
the  neccessarily  rather  rough  usage  attending  field  work  but  appear 
to  be  about  as  good  as  any  available  for  the  lighter  cameras.  For 
the  larger  view  cameras  wooden  tripods  of  ample  size  are  very 
satisfactory. 

A  number  of  types  of  clamps  and  universal  joints  are  obtainable 
for  the  smaller  cameras.  Of  these  the  writer  has  found  the  form 
designated  as  the  Optipod  by  the  Eastman  Kodak  Company  to  be 
very  convenient  both  as  a  universal  joint  for  use  with  the  tripod 
and  also  as  a  substitute  for  the  latter  in  connection  with  some  other 
support.  By  modifying  the  shape  of  the  jaws  to  a  slight  extent 
this  instrument  can  be  made  to  take  a  tighter  grip  on  objects  not 
injured  by  marring  and  has  been  used  extensively  by  the  writer 
in  conjunction  with  his  geologic  hammer.  The  latter  can  be  driven 
into  a  slight  rise  on  the  ground,  or  into  a  fence  post  or  tree  and  the 
optipod  then  attached  to  the  handle.  Another  method  is  to  build 
a  rude  tripod  or  lean-to  pile  of  any  available  sticks  and  clamp  to 
some  part  of  this.  By  such  methods  the  writer  has  found  that  in 
some  types  of  country  it  was  possible  to  get  on  without  carrying 
the  tripod  and  still  to  support  the  camera  for  time  exposures  for 
nearly  all  pictures.  Some  sort  of  universal  joint  is  worth  its 
weight  in  places  where  it  is  difficult  to  find  footing  for  the  tripod 
and  at  the  same  time  direct  the  camera  with  accuracy  toward  the 
desired  subject.  With  the  joint  one  can  use  the  available  footing 
even  though  it  be  very  unsymmetrical  and  then  do  the  aiming  as 
another  operation  with  the  adjustment  afforded  by  the  ball  and 
socket.  If  many  detailed  pictures  of  small  objects  lying  on  the 
ground  or  in  out  of  the  way  places  are  to  be  attempted  the  uni- 
versal joint  is  indispensable  since  by  its  use  the  camera  may  be 
pointed  directly  down  or  in  any  other  direction  with  equal  ease. 

The  writer  has  not  seen  an  equally  satisfactory  universal  joint 
for  larger  cameras  on  the  market  but  has  used  a  simple  one  of  his 
own  construction  for  a  number  of  years.  This  consists  of  a  simple 
right  angle  of  i"  x  1  \"  band  iron  with  arms  of  2"  and  6"  respective- 
ly. Each  arm  has  toward  the  end  both  a  clear  J"  hole  and  a  hole 
tapped  with  ^"-20  thread  (approximately  the  standard  socket 
thread) .    With  the  angle  is  an  extra  tripod  screw  which  is  kept  in 


28  IOWA  STUDIES  IN  NATUEAL  HISTORY 

one  of  the  tapped  holes  when  not  in  use.  The  angle  is  clamped  at 
the  top  of  the  wooden  tripod  by  means  of  the  tapped  hole  in  either 
arm  and  the  camera  then  clamped  sideways  to  the  other  arm  by 
means  of  the  extra  screw  and  clear  hole.  The  angle  is  thus  rotat- 
able  on  the  tripod  and  with  the  motion  of  the  camera  on  the  other 
arm  provides  for  it  a  full  alti-azimuth  mounting  which  is  far  more 
rigid  then  would  be  a  clamp  with  movable  parts.  The  device  weighs 
nearly  a  pound  but  is  still  proportionately  light  compared  to  the 
camera  it  supports. 

Some  tripods  may  be  fitted  with  tilting  heads  which  serve  the 
same  purpose  as  universal  heads.  As  in  the  case  of  tripods  them- 
selves these  are  difficult  to  construct  of  the  requisite  strength  com- 
bined with  lightness  and  are  worth  examining  with  care  or  trial  in 
actual  use  before  purchasing. 

Stereo  photography  is  becoming  more  popular  among  amateur 
photographers  and  is  of  great  value  to  geologists  in  certain  in- 
stances. It  is  doubtful  if  stereo  cameras  with  their  necessary 
extra  bulk  will  be  carried  for  routine  work  but  occasional  stereo 
pictures  may  be  taken  by  moving  the  camera  between  two  succes- 
sive exposures.  A  light,  flat  metal  link  of  a  length  half  the  de- 
sired shift  has  been  used  by  the  writer  and  makes  the  shift  more 
easily  achieved  than  if  the  whole  tripod  were  to  be  moved.  Dr. 
F.  E.  Wright x  suggests  a  shift  of  from  one  to  five  percent  of  the 
distance  to  the  principal  object  to  be  photographed. 

Exposure  Meters,  Tables  and  Computing  Devices 

There  are  many  mechanical  devices  for  determining  the  ex- 
posure to  be  given  under  any  set  of  conditions.  There  are  many 
very  successful  photographers  who  estimate  exposure  as  the  result 
of  experience  without  reference  to  any  sort  of  artificial  aid.  The 
writer  has  used  a  few  of  the  devices  which  are  available  and  has 
also  done  considerable  satisfactory  photography  without  any  of 
them.  He  feels  that  the  best  procedure  for  the  average  person  is 
to  use  some  one  of  the  many  good  calculating  devices  and  at  the 
same  time  for  each  picture  estimate  previously  to  using  the  calcu- 
lator the  exposure  he  would  give.  He  can  then  compromise  be- 
tween his  own  estimate  and  the  reading  of  the  calculator  and  let 
the  finished  picture  be  the  proof.  On  the  one  hand  the  constant 
effort  on  the  part  of  the  operator  to  forecast  the  result  of  the  ealcu- 

i  Wright,  F.  E.     Private  communication. 


PHOTOGRAPHIC  PRACTICE  29 

lation,  which  may  be  considered  in  most  cases  reasonably  correct, 
and  on  the  other  hand  his  observation  of  just  how  his  estimates 
differ  justifiably  from  the  calculated  ones  prove  to  be  very  effective 
in  building  up  a  vivid  exposure  instinct  or  judgment. 

The  various  exposure  determining  devices  may  be  divided  into 
four  classes.  The  first  class  consists  of  meters  proper  or  actino- 
meters  which  make  a  direct  measurement  of  the  light  at  the  time 
the  picture  is  taken  by  means  of  sensitized  paper.  These  are  useful 
in  connection  with  landscape  or  architectural  photography  but  are 
less  satisfactory  in  detail  photography  where  one  is  concerned 
with  the  light  reflected  by  a  small  object.  The  second  class  includes 
the  type  of  meter  in  which  the  light  is  judged  by  viewing  through 
a  wedge  or  series  of  screens  of  variable  density.  These  have  the 
advantage  that  one  can  deal  with  the  light  directly  and  exclusively 
from  the  subject.  They  are  subject  however  to  the  disadvantage 
that  the  human  eye  varies  greatly  in  its  susceptibility  to  light 
under  varying  conditions.  Even  with  the  precaution  of  allowing 
the  eye  to  come  to  rest  by  closing  it  for  a  time  there  is  doubtless 
much  variation  in  the  readings  obtained  from  identical  lightings 
of  the  same  subject  wih  variations  in  the  condition  of  the  eye  of 
the  observer.  In  spite  of  this  drawback  this  type  of  meter  is 
probably  among  the  most  useful.  The  third  type  consists  of  the 
numerous  calculators,  circular  and  linear.  These  are  all  similar 
in  that  they  take  account  of  condition  of  the  sun,  time  of  day, 
season  of  year,  nature  of  the  subject,  speed  of  the  film  and  aperture 
of  the  lens.  They  also  employ  in  common  the  logarithmic  slide 
rule  principle  in  the  computing.  They  differ  in  the  arrangement 
of  the  various  factors  and  movable  parts  and  in  the  range  and 
manner  of  statement  of  the  various  factors.  They  are  the  most 
convenient  and  portable  of  the  four  types  and  illustrate  most 
vividly  the  effect  of  the  various  factors  in  controlling  the  tre- 
mendous range  in  practical  exposure  times  under  various  con- 
ditions. The  fourth  type  is  the  exposure  table  such  as  that  issued 
by  American  Photography.  These  tables  are  more  complete  than 
any  of  the  calculators  and  handle  a  wider  range  of  conditions. 
They  consist  essentially  of  a  series  of  logarithms  (to  the  base  2 
or  4)  of  the  values  of  the  several  factors  which  may  conveniently 
be  added  mentally  to  secure  the  logarithm  of  the  exposure. 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

Miscellaneous  Accessories 

For  work  with  the  larger  view  cameras  a  focusing  cloth  will 
be  needed.  Rubber  backed  bellows  cloth  is  more  completely  opaque 
but  plain  black  cloth  is  less  warm  to  work  under  and  will  do  for 
most  conditions.  With  some  ground  glass  cameras  a  small  col- 
lapsible hood  is  attached  and  in  these  a  sufficient  view  of  the 
image  is  available  without  the  focusing  cloth. 

A  changing  bag  permits  loading  and  unloading  of  films  in  the 
daytime  and  will  be  needed  where  many  pictures  are  to  be  taken 
in  one  day  on  cut  films  or  plates.  At  night  away  from  bright 
artificial  light  one  may  find  many  places  where  plates,  even  of 
panchromatic  grades,  may  be  changed  safely,  if  one  works  quickly 
and  with  due  care. 

A  self  timer  is  useful  in  some  instances.  For  example  if  one 
wishes  in  the  picture  to  point  to  a  certain  contact  and  is  working 
alone  he  may  by  means  of  the  self  timer  be  able  to  appear  in  the 
picture.  In  other  cases  where  brush  has  to  be  held  aside  the  self 
timer  may  be  used  to  advantage. 

The  choice  of  ray-filters  will  depend  on  the  films  which  are  to 
be  used.  If  one  or  two  only  are  carried  those  in  slip-on  mounts  are 
most  convenient.  For  using  a  larger  number  interchangeably  the 
writer  has  a  small  cell  which  slips  on  the  lens  cell  and  holds  in 
turn  the  filter  by  means  of  a  light  spring  ring.  The  filters  used 
are  unmounted  but  cemented  in  glass.  He  has  carried  six  of  these 
filters  in  chamois  pockets  in  a  metal  pill  box  daily  for  nearly 
twelve  months  in  the  tropics  without  breakage  and  without  serious 
deterioration. 

For  most  subjects  a  yellow  filter  (K*  of  Eastman  Co.)  is  best, 
next  to  this  the  orange  (G),  red  (A),  deep  red  (F),  and  green 
(B)  are  useful  in  the  order  named.  All  of  the  last  named  can 
be  used  only  with  panchromatic  films  or  plates.  Exposure  factors 
and  other  data  for  the  use  of  these  filters  can  be  obtained  from 
the  makers. 

Lenses  should  be  kept  clean,  preferably  by  good  protection 
rather  than  by  wiping.  A  small  and  thin  lens  cap  is  useful  for  this 
purpose  especially  in  the  tropics  and  in  damp  situations.  If  ab- 
solutely necessary  to  wipe  a  lens,  the  dust  should  first  be  dislodged 
by  holding  the  lens  inverted,  and  brushing  or  flicking  the  dust  from 
the  surface  as  it  may  contain  hard  particles  which  would  scratch 


PHOTOGRAPHIC  PRACTICE  31 

the  glass.  A  clean  piece  of  soft  cloth  may  be  used  to  wipe  the 
surface  gently  but  tissue  paper  or  special  lens  paper  is  best  of  all 
and  if  protected  will  always  be  clean. 

Methods  of  carrying  the  camera  and  accessories  will  differ  ac- 
cording to  personal  choice.  To  some  a  carrying  bag  seems  most 
convenient  and  others  prefer  a  sling  case  or  some  sort  of  belt  at- 
tachment. The  writer  cannot  refrain  from  urging  the  adoption 
of  some  systematic  plan  for  the  transportation  of  the  camera  and 
other  photographic  equipment  and  the  provision  of  small  cloth 
or  leather  bags  or  cases  to  exclude  dust  and  afford  reasonable  pro- 
tection to  the  instruments.  At  best  field  work  is  hard  on  instru- 
ments of  all  sorts  but  the  condition  of  some  cameras,  compasses, 
barometers  and  handlevels  the  writer  has  seen  in  the  hands  of 
geologists  was  due  to  lack  of  even  ordinary  care  and  attention  in 
the  matter  of  drying  and  cleaning.  Several  of  the  instruments 
mentioned  above  cost  as  much  and  are  worthy  of  the  same  care  as  a 
good  watch. 

FIELD  PRACTICE 
Pre-Field  Testing 

Unless  one  takes  into  the  field  only  equipment  of  which  he  has 
made  frequent  and  recent  use  it  is  desirable  to  make  a  few  tests 
to  make  sure  that  it  is  in  working  order  and  to  become  accustomed 
to  any  pecularities  it  may  possess.  There  are  a  number  of  defects 
not  readily  noticed  which  might  easily  cause  the  entire  loss  of  many 
pictures  if  not  detected.  Leaks  which  admit  light  may  occur  in 
the  bellows  or  in  other  parts  of  the  camera  or  the  slides  or  backs 
of  plate  holders  and  film  pack  adapters  may  be  similarly  defective. 
Lenses  sometimes  become  loosened  or  uncemented  and  cause  poor 
definition  or  flare.  The  focusing  scale  may  not  be  properly 
placed  or  may  not  be  accurately  graduated.  The  upright  yoke 
which  carries  the  lens  not  uncommonly  becomes  bent  and  changes 
the  focus  relation,  especially  in  cameras  with  short  bellows.  The 
focus  may  readily  be  tested  on  a  roll  film  camera  by  removing 
the  back  and  laying  a  ground  glass  strip  with  its  ground  side  in 
contact  with  the  rollers.  If  the  ground  glass  is  not  convenient  a 
strip  of  tracing  cloth  or  paper  stretched  taut  may  be  used. 

One  of  the  features  most  in  need  of  testing  is  the  shutter.  This 
should  work  decisively  and  if  not  with  times  as  marked  the  actual 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

times  should  be  known.  There  are  various  methods  of  testing  the 
speed  of  shutters  of  which  a  few  will  be  mentioned.  A  bicycle 
wheel  carrying  a  single  bright  object  on  its  outer  edge  can  easily 
be  rotated  at  a  speed  which  is  known  within  5  percent  or  less. 
This  should  be  photographed  from  a  point  near  the  extended  axis 
of  the  wheel  using  the  several  speeds  to  be  tested.  The  aperture 
and  lighting  should  be  such  as  to  give  a  fairly  strong  image  for  the 
bright  spot.  After  developing  the  film  or  plate  the  amount  of 
angular  motion  can  easily  be  measured  and  the  speed  computed. 
With  a  little  planning  all  the  speeds  marked  can  be  tested  on  one 
or  two  films  if  the  general  lighting  is  dull  enough  so  that  most 
of  the  view  is  much  underexposed  and  the  camera  is  pointed 
differently  for  successive  views.  Any  piece  of  machinery  rotating 
at  known  speed  and  carrying  a  bright  spot  (such  as  a  thumb 
tack  illuminated  from  behind  with  a  strong  light)  can  be  similarly 
used  if  the  speed  be  of  about  the  right  value.  From  one-fourth 
to  a  full  revolution  during  the  exposure  is  best  for  accurate 
measurement. 

A  very  simple  method  is  to  arrange  two  carbons  to  give  a 
small  arc  light  on  an  alternating  current  circuit.  If  this  light  be 
photographed  in  a  dark  room  while  swinging  the  camera  about 
slowly  the  image  will  be  a  line  of  dots.  In  the  case  of  a  60  cycle 
circuit  there  will  be  120  flashes  per  second  and  exposures  from 
1/50  up  to  two  or  three  seconds  can  be  measured  with  reasonable 
accuracy. 

A  falling  body  or  a  pendulum  may  be  used  but  the  computation 
would  be  somewhat  more  difficult  than  in  the  foregoing  examples. 
Various  other  methods  will  occur  to  anyone  needing  to  test  a 
shutter,  according  to  the  facilities  he  has  at  hand.  The  writer  has 
never  attempted  it  but  a  satisfactory  test  could  probably  be  made 
by  photographing  at  short  range  an  automobile  traveling  at  known 
speed. 

Placing  the  Camera 

In  placing  the  camera  the  first  and  prime  consideration  is 
visibility  of  the  feature  it  is  desired  to  portray.  In  open  country 
this  matter  offers  little  difficulty  but  in  a  wooded  region  the  veg- 
etation sometimes  interferes  either  with  getting  a  view  out  from  the 
camera  stand  to  a  distant  object  or  with  getting  a  view  in  toward  a 
shaded  rock  feature.     Another  factor  which  has  to  be  considered 


PHOTOGRAPHIC  PRACTICE  33 

at  the  same  time  is  the  support  for  the  camera.  If  the  picture 
is  to  be  taken  as  a  snapshot  this  part  is  easy  but  for  a  time  exposure 
one  has  to  have  suitable  footing  for  the  tripod  or  some  object 
to  which  to  clamp  the  camera.  If  a  tree  or  other  solid  object  is  at 
hand  the  camera  may  be  blocked  upon  it  or  held  against  it  with  or 
without  blocking  in  almost  any  position.  Such  a  position  may 
prove  a  little  awkward  for  focusing  on  the  ground  glass  but  in  most 
cases  this  may  be  done  "free-hand"  and  such  slight  errors  as  are 
present  in  the  focus  are  more  than  taken  care  of  with  the  increased 
depth  resulting  from  using  a  small  stop.  If  one  uses  a  tripod 
a  universal  joint,  will  be  found  extremely  convenient  in  orienting 
the  camera  in  difficult  situations  after  some  sort  of  footing  for  the 
tripod  has  been  found. 

A  third  factor  which  should  be  taken  into  account  so  far  as  pos- 
sible under  the  limitations  imposed  by  those  of  visibility  and  sup- 
port is  that  of  most  favorable  viewpoint  and  lighting.  Features 
which  can  be  conveniently  visited  at  any  time  of  the  day  enroute 
to  more  distant  places  or  which  are  of  sufficient  importance  should 
be  studied  in  order  to  choose  the  most  effective  light  conditions. 
Practically  all  the  features  which  geologists  have  occasion  to 
photograph  will  be  found  to  be  more  clearly  outlined  in  the  oblique 
rays  of  the  mid-morning  or  mid-afternoon  sun  than  in  that  of 
noonday  and  with  a  reasonable  amount  of  intelligent  practice  in 
estimating  exposure  good  pictures  may  be  taken  from  sunrise  to' 
sunset.  Low  terraces  and  similar  features  are  frequently  uni- 
formly grass  covered  and  hardly  distinguishable  except  in  early 
morning  or  late  afternoon  light.  In  the  case  of  detail  views  of 
rock  surfaces  the  choice  of  time  depends  on  the  attitude  of  the 
surf  ace  in  relation  to  the  sun.  Such  subjects  as  glacial  striae  or 
slicken-sides  which  depend  on  very  sharp  oblique  light  for  their 
proper  illumination  are  not  always  situated  in  such  a  position  that 
the  sun  ever  strikes  them  properly.  (Figure  1).  These  may 
sometimes  advantageously  be  illuminated  with  an  artificial  light 
at  night  or  by  means  of  a  mirror  after  shading  them  from  the 
direct  natural  light. 

In  photographing  objects  directly  toward  the  sun,  which  is 
sometimes  necessary  or  even  desirable,  care  must  be  taken  to 
shade  the  lens,  especially  if  a  wide  aperture  is  used.  Many  sub- 
jects will  appear  best  when  entirely  in  the  shade.  This  is  particu- 
larly true  of  such  features  as  bedding,  schistosity  or  other  struc- 


34  IOWA  STUDIES  IN  NATURAL  HISTORY 

tures  in  which  the  chief  distinction  between  different  parts  is  a 
color  difference  rather  than  a  difference  in  relief  or  configuration. 
If  such  a  surface  has  any  considerable  irregularity  and  is  photo- 
graphed in  bright  sunlight  there  is  danger  that  the  essential  color 
differences  will  be  entirely  subordinated  to  the  incidental  light 
and  shade  distinctions. 

In  addition  to  the  problems  of  placing  the  camera  under 
normal  conditions  there  are  those  of  keeping  it  placed  in  a  high 
wind  or  keeping  it  dry  in  rainy  weather.  If  camera  or  holders 
become  wet  superficially  they  should  be  wiped  at  the  first  oppor- 
tunity and  laid  where  they  can  become  thoroughly  dry.  Salt 
water  and  spray  are  particularly  insidious  because  the  deliques- 
cent salts  maintain  a  condition  of  stickiness  and  are  rust  breeders 
in  addition  to  the  damage  to  films.  Camera  and  film  cases  of 
rubber  coated  cloth  are  very  useful  in  wet  regions. 

Focusing 

Objects  100  feet  or  more  away  offer  no  problem  in  focusing 
but  for  nearer  objects  the  camera  must  either  be  focused  on  a 
ground  glass  or  by  means  of  a  scale  set  to  the  estimated  distance. 
If  the  view  involves  a  considerable  range  of  distances  for  near 
objects  one  should  focus  or  set  to  some  feature  which  is  about 
midway  on  the  focal  scale  of  the  whole  field  of  view  and  use  a 
very  small  stop.  If  it  is  desired  to  include  distant  objects  and 
foreground  in  the  picture  the  focus  should  be  set  midway  (on  the 
focus  scale)  of  the  two  distances  and  the  lens  stopped  down  to 
the  necessary  small  aperture.  (Figures  2  and  3.  See  table  of 
depths  of  definition). 

It  is  desirable  in  many  detail  pictures  to  place  some  object  of 
known  size  in  the  field  of  view  to  serve  as  a  scale.  In  such  a  case 
the  object,  such  as  the  geologist's  hammer,  his  pencil  or  some 
other  convenient  object  should  be  placed  as  unobtrusively  as 
possible  toward  the  bottom  or  one  side  and  objects  of  unusual 
character  or  of  temporary  interest  avoided  as  much  as  possible. 
In  views  of  large  rock  exposures  a  human  figure  makes  a  good 
scale  but  should  not  be  so  placed  as  to  divert  interest  from  the 
geologic  features.     (Figure  4). 

Choice  of  Plates  or  Films 
If  one  is  operating  a  roll  film  camera  the  choice  may  be  con- 


PHOTOGRAPHIC  PRACTICE  35 

sidered  to  have  already  been  made.  With  a  plate  camera  there 
are  a  number  of  grades  of  film  or  plate  which  may  be  used  ac- 
cording to  the  nature  of  the  subject.  Probably  the  best  for 
standard  use  is  some  good  make  of  orthochromatic  cut  film.  For 
a  few  subjects  such  as  rock  exposures  which  are  wholly  in  sunlight 
or  similar  objects  with  little  color  variation  there  is  little  purpose 
in  using  a  color  filter  but  most  pictures  will  be  considerably 
improved  by  the  use  of  a  medium  filter  such  as  K2.  Clouds  will 
be  made  more  distinct  and  visibility  through  nearby  haze  increased 
by  such  a  filter.  Views  which  unavoidably  combine  brilliant  sun- 
light and  rather  deep  shadows  can  usually  be  taken  more  success- 
fully with  a  filter  than  without.  Very  distant  haze-obscured 
skylines  require  a  deeper  filter  such  as  the  red  F  and  a  panchro- 
matic film  for  their  successful  delineation.  (Figures  5  and  6). 
The  lighter  red  A  and  the  orange  G  are  occasionally  useful  in 
taking  geologic  subjects  and  more  rarely  the  green  JB  filter. 
(Figure  7). 

For  the  photography  of  bright  colored  objects,  such  as  flowers, 
animals  or  other  natural  objects  filters  and  orthochromatic  or  in 
some  cases  panchromatic  films  are  essential.  It  is  rarely  that  the 
geologist  will  have  occasion  to  seek  exceptional  rapidity  in  the 
films  he  uses  and  it  is  well  to  remember  that  the  medium  speeds 
of  film  have  greater  latitude  and  finer  grain  than  the  faster  ones. 
In  a  very  few  instances  the  use  of  process  films  with  their  very 
great  contrast  is  desirable  but  it  should  not  be  undertaken  unless 
other  methods  have  failed  to  secure  pictures  of  very  flat  subjects 
and  one  can  check  upon  the  films  by  having  them  developed  at 
once.  The  latitude  of  these  films  is  so  slight  that  the  exposure  must 
be  estimated  with  much  greater  care  and  the  contrast  is  so  great 
that  objects  with  any  range  of  light  and  shade  are  likely  to  produce 
disappointing  results. 

Determination  op  Exposure 

The  factors  involved  in  determining  the  length  of  exposure  for 
a  given  picture  are  as  follows : 

1.  Latitude 

2.  Season  of  year 

3.  Time  of  day 

4.  Condition  of  sky  and  atmosphere 

5.  Distance  of  object 

6.  Illumination  of  object 


36  IOWA  STUDIES  IN  NATUEAL  HISTORY 

7.  Color  and  lustre  of  object 

8.  Speed  of  film 

9.  Filter 

10.    Aperture  of  lens 

Fortunately  the  calculation  of  exposures  from  these  ten  factors 
does  not  need  to  be  carried  out  with  great  numerical  accuracy. 
In  fact  in  practice  several  of  the  factors  can  be  ignored  most  of 
the  time  if  the  operator  is  alive  to  the  relative  importance  of  all 
the  factors  and  knows  when  a  given  factor  becomes  of  large 
importance.  For  operations  from  day  to  day,  the  latitude  and 
season  of  the  year  are  constant  and  need  be  taken  into  account  but 
once.  The  speed  of  the  film  is  another  factor  which  need  be  con- 
sidered only  as  one  changes  to  another  grade.  Other  factors  may 
be  combined  in  making  rough  mental  calculations.  For  example 
the  distance,  illumination  and  color  of  objects  may  all  be  combined 
under  the  general  head  of  subject.  For  a  number  of  years  the 
writer  has  used  a  scheme  for  simplifying  the  calculation  of  ex- 
posure which  has  proved  to  be  very  useful.  It  is  based  on  the 
principle  that  the  exposure  time  and  the  area  of  the  aperture  are 
inversely  proportional  for  a  given  set  of  conditions.  In  other 
words  for  a  given  subject  and  lighting  a  definite  amount  of  light 
must  be  admitted  and  it  is  immaterial  from  the  standpoint  of 
exposure  whether  this  be  accomplished  quickly  through  a  large 
aperture  or  more  slowly  through  a  correspondingly  smaller  aper- 
ture. In  computing  exposure  we  can  therefore  concern  ourselves 
first  with  the  amount  of  light  to  be  admitted  as  the  main  problem 
and  then  solve  at  our  convenience  the  subordinate  problem  of  the 
aperture  and  dependent  time  of  exposure  with  reference  to  the 
needed  depth  of  focus,  stopping  of  motion  or  other  considerations. 
The  practical  application  of  this  method  consists  in  the  establish- 
ment of  a  series  of  numbers  which  are  proportional  to  the  net 
brilliancy  or  photographic  powers  of  a  series  of  subjects  and 
which  are  obtained  by  dividing  the  appropriate  U.S.  stop  number 
by  the  proper  exposure  time  in  seconds.  By  temporarily  elimi- 
ating  factors  one,  two,  eight,  nine  and  ten  from  consideration  and 
combining  the  other  factors  it  is  possible  for  one  gradually  to 
build  up  in  memory  the  results  of  accumulated  experience  in  some 
such  fashion  as  shown  by  the  table  below.  The  values  given  are 
those  indicated  roughly  by  the  writer's  experience;  each  worker 
will  do  best  with  a  scale  of  his  own  making. 


PHOTOGRAPHIC  PRACTICE 


37 


CONDITIONS 

BEILLIANCY 
NUMBER 

STOP-TIME 
COMBINATIONS 

Bright  sun 
Average  landscape 

200 

U.S.     4-1/50 

U.S.     8-1/25 

U.S.  40-1/5 

etc. 

Bright  sun 
Distant  marine 
view,  clouds 

800 

U.S.  16-1/50 
etc. 

Bright  sun 
Near  view  of 
quarry  face, 
50  feet 

50 

U.S.      4-1/12  about 
U.S.  128  -  2  1/2  about 

Dull  light 
Shade,  near 
view  of  outcrop, 
J    10  feet 

5 

etc. 

It  will  be  apparent  that  it  is  vastly  easier  to  remember  a  series 
of  numbers  such  as  200,  50,  25,  10,  etc.,  than  to  keep  in  mind  the 
numerous  combinations  of  stop  and  time  which  have  been  used 
in  various  equivalent  situations.  In  the  use  of  this  system  the 
results  obtained  in  the  fundamental  scale  can  easily  be  modified 
for  effects  of  latitude,  film  speed  and  filter  according  to  theory 
or  the  operator's  experience. 

The  use  of  exposure  computors  or  meters  along  with  such  a 
mnemonic  system  will  enable  one  to  build  up  a  memory  scale  more 
rapidly,  to  observe  more  closely  the  various  values  of  the  different 
factors  and  suggest  modifications  to  the  results  given  by  the  various 
devices  under  special  conditions  and  interpretations  peculiar  to 
the  operator.  More  complete  data  are  contained  in  the  American 
Photography  Exposure  tables  which  are  of  great  value  for  occas- 
ional reference  even  if  not  used  for  every  exposure. 

At  the  outset  it  is  very  desirable  to  have  an  idea  of  the  total 
arithmetical  range  represented  by  the  various  factors  which  affect 


38 


IOWA  STUDIES  IN  NATURAL  HISTORY 


exposure  and  the  writer  has  attempted  to  indicate  some  of  these 
in  the   table   below.     (Figure   9).     The   numbers   given  may  be 


TABLE  SHOWING  RANGE  OF  NOON  ILLUMINATION 
FOE  LATITUDE 


Latitude 

Relative 

Brilliancy 

Summer 

Winter 

0-20 

1 

3/4 

30 

1 

3/8 

40 

1/2 

1/4 

50 

1/2 

1/10 

60 

1/2 

1/12 

TABLE  SHOWING  RANGE  OF  BRIGHT  SUN 

ILLUMINATION  FOR  TIME  OF  DAY 

LATITUDE    40° 

Hour                                              Relative  Brilliancy 

12 

Summer                                   Winter 

1 

1/2 

11     1 

1 

V2 

10     2 

1 

3/8 

9     3 

3/4 

1/4 

8     4 

1/2 

1/16 

7     5 

1/2 

1/32 

6     6 

1/4 

5     7 

1/32 

PHOTOGRAPHIC  PRACTICE  39 

advantageously  used  to  modify  the  brilliancy  numbers  in  expand- 
ing the  table  given  above. 

Filters  vary  in  their  required  exposures  from  2  to  30  times  the 
normal  according  to  the  color  and  density.  If  we  take  the  range 
of  basic  subject  exposures  as  from  1  to  2000,  that  of  the  season  and 
latitude  factors  as  1  to  12,  of  the  time  of  day  1  to  32,  of  the  filters 
1  to  15,  and  of  film  speeds  it  will  be  apparent  that  the  range  in 
exposure  required  is  very  close  to  1  to  12,000,000.  If  to  this  enor- 
mous range  we  add  the  effect  of  variation  of  apertures  we  find 
the  possible  theoretical  range  in  exposure  times  is  of  the  order 
of  a  billion  fold. 

When  the  amount  of  exposure  needed  has  been  estimated  there 
remains  the  single  problem  of  choosing  a  stop  and  thus  determining 
the  time  of  exposure.  There  are  several  possible  governing  con- 
siderations. If  the  exposure  is  to  be  made  while  holding  the 
camera  in  the  hand  the  exposure  cannot  safely  be  made  longer 
than  1/25  second  by  most  people.  A  few  can,  by  standing  very 
rigidly  and  holding  the  breath,  make  exposures  of  1/10  second  or 
more  without  blurring  the  picture  but  this  should  not  be  attempted 
until  the  operator  has  made  a  number  of  tests  near  to  the  laboratory 
to  learn  his  individual  limitations.  The  speed  of  moving  objects, 
such  as  that  of  a  breaking  wave  or  of  a  tree  swaying  in  the  wind 
may  determine  the  greatest  permissible  exposure  time.  If  con- 
siderable depth  of  focus  is  needed  for  details  of  close  objects  or 
to  bring  a  foreground  in  sharp  focus  it  will  be  necessary  to  stop 
down  to  a  small  aperture.  (Figure  2).  The  depth  of  focus  ob- 
tained for  different  apertures  and  focal  lengths  is  given  in  the 
table  below.  So  many  possible  errors,  some  inherent  in  lenses 
and  others  inherent  in  the  adjustments  and  nature  of  the  subject, 
are  eliminated  or  reduced  by  using  time  exposures  and  small  aper- 
tures that  the  writer  in  common  with  many  other  geologists  has 
found  it  advantageous  to  follow  this  practice  with  a  large  pro- 
portion of  the  pictures  taken,  including  landscapes.  To  those  who 
take  great  pride  in  the  performance  of  a  high  grade  anastigmat 
lens  such  advice  may  seem  not  to  leave  room  for  individual  skill 
and  craftmanship  but  it  is  the  writer's  belief  that  other  aspects  of 
photographic  technique  offer  abundant  opportunities  for  exercise  of 
skill  and  that  in  the  tremendously  practical  and  necessarily  sec- 
ondary business  of  taking  geologic  photographs  the  chance  of  cor- 
recting many  difficulties  in  one  operation  should  not  be  ignored. 


40 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Among  these  are  faulty  estimates  of  distance,  poor  adjustments 
of  camera  parts,  lenses  inferior  to  the  best,  and  depth  in  the 
subject.     (Figure  8). 

Making  the  Record 

A  record  should  be  made  at  the  time  the  picture  is  taken.  This 
should  include  the  approximate  date,  the  location  of  the  subject 
by  state,  by  section  or  project  and  specifically  on  a  map  like  any 
other  geologic  observation.  A  full  title  and  statement  of  the 
import  of  the  picture  should  be  recorded.  The  photographic  data 
such  as  time  of  exposure,  aperture,  time  of  day,  conditions  of 
lighting,  etc.  are  not  needed  for  the  geologic  record  but  are  in- 
valuable to  one  who  is  attempting  to  improve  his  percentage  of 
good  pictures.  By  inspecting  and  criticising  the  negatives  when 
they  are  returned  from  the  laboratory  with  the  record  of  conditions 
in  hand  one's  technique  is  improved  more  rapidly  than  by  any 
method  except  that  of  developing  the  pictures  immediately  after 
they  are  taken. 

Film  should  be  developed  as  soon  after  exposure  as  possible 
since  films  deteriorate  much  more  quickly  after  exposure  than 
before.  Under  favorable  climatic  conditions  films  may  be  kept 
for  several  weeks  without  marked  change  but  the  practice  is  not 
good  where  other  arrangements  can  be  made,  not  only  because  of 
chance  of  spoiling  but  because  of  the  desirability  of  knowing  the 
quality  of  results  while  still  in  the  field. 

Tables 
Many  useful  tables  are  contained  in  booklets  of  the  Eastman 
and  other  camera  makers  and  in  photographic  magazines.     The 
following  are   presented  as  those   most  frequently  used  in  the 
field. 


TABIxE   OF   HYPEBFOCAL   DISTANCES  1 


Focal  Length 

f/4.5 

f/8 

f/16 

f/32 

f/64 

8" 

250 
142 

99.5 

64 

37.5 

17.2 

141 
80 
56 
36 
21.1 

70.4 

40 

28 

18 

10.6 

35.2 

20 

14 

17.6 

6" 
5" 

10.0 
7.0 

4" 
3" 

9 
5.3 

2.4 

4.5 
2.6 

2" 

1          9.7 

4.8 

1.2 

i  The  hyperfocal  distance  for  a  given  aperture  and  focal  length  is  that 


DEPTH    OF    DEFINITION    TABLE 


Lenses  com- 
monly used 
on    size 

Distance 

focused 

on 

f/4.5 

f/16 

f/64 

3%"x5%" 

100 

25 

6 

60'-inf. 

22'-28' 

32'-inf. 
17'-52' 
5%'-6%' 

lO'-inf. 
8'-inf. 
4y2'-10' 

3%"x4%" 

100 

25 

6 

48'-inf. 
20'-33' 

21'-inf. 
13y2'-inf. 

5'-7y2' 

7y2'-inf. 

6'-inf. 

3%'-20' 

2%"x4%" 

100 

25 

6 

35'-inf. 
18'-30' 
5%'-6V2' 

17'-inf. 
liy2'-inf. 
4%'-8%' 

6'-inf. 
5'-inf. 
3y2'-inf. 

beyond  which  all  objects  are  in  focus  when  the  lens  is  focused  at  infinity. 
This  table  is  computed  on  the  basis  of  a  circle  of  diffusion  of  1/200  inch. 
Below  the  heavy  line  are  allowable  aperture  —  focal  length  combinations  for 
sharp  foreground  with  a  camera  levelled  on  level  ground. 


Fig.  1.  Eipple  marks  on  several  bedding  planes  in  Proterozoic  quartzite. 
Baraboo  Region,  Wisconsin.  An  example  of  a  photograph  to  be  taken  suc- 
cessfully with  the  sun  in  one  limited  position  at  a  definite  time  of  day. 


Fig.   2.      View  near   Washington,  D.  C. 
aperture  to  give  depth  of  definition. 


Showing  result   of  using   small 


\\m> 


Fig.  3.  View  of  channel  of  Mapulehu  Stream,  interior  of  East  Molokai, 
Hawaii.  A  view  requiring  a  small  aperture  for  depth  of  definition  even  at 
the  expense  of  sharpness  in  the  moving  water. 


Fig.  4.     Outcrop  of  Pennsylvanian  coal  measures  near  Dante,  Virginia. 
An  example  of  the  unobtrusive  use  of  the  human  figure  as  a  scale. 


Fig.  5.  View  across  Monocacy  Valley  in  Maryland.  Taken  with  portrait 
film  and  no  filter.  Detail  is  missing  in  the  distant  portions  of  the  view. 
See  Fig.  6. 


Fig.  6.  Same  view  as  Fig.  5.  Taken  with  panchromatic  film  and  deep 
red  filter  (F).  The  improvement  in  detail  in  the  middle  and  distant  parts 
of  the  view  is  apparent. 


Fig.  7.  View  of  liana uma  Bay,  Koko  Head  region,  Oahu,  Hawaii. 
Taken  with  panchromatic  fiJm  and  orange  (G)  filter.  The  delineation  of 
underwater  reef  detail  over  the  entire  area  of  the  bay  would  be  far  less 
satisfactory  without  the  filter  and  appropriate  film. 


^J^^^^^W/^^f^S^PS^^ 

i^^^t^^sst^'^  ^" *  ^y. 

ma,'  -%**>,>     '            ^  ■       "    i  '               f     ^       ^      M  i.        ''      m 

Fig.  8.  Detail  of  weathering  of  shale,  near  Norton,  Virginia.  Taken 
with  auxiliary  lens  of  portrait  type.  Example  of  satisfactory  definition 
wrought  over  oblique  field  with  a  very  imperfect  optical  system  by  means 
of  very  small  aperture. 


Fig.  9.  View  of  fall  in  glen  at  Pictured  Rocks,  northeast  Iowa.  Taken 
at  about  7:30  P.M.  in  late  April  in  dark,  shaded  glen  under  trees.  Ex- 
posure about  ten  minutes  with  f/32  aperture.  Showing  large  increase  in 
necessary  exposure  at  late  afternoon  hours  and  satisfactory  results  if  this 
condition  is  met. 


THE  DESERT  STRIP  OP  WEST  MOLOKAI1 

Chester  K.  Wentworth 

University  of  Iowa- 

INTEODUCTION 

Location 

The  west  end  of  the  island  of  Molokai  is  crossed  by  a  strip  of 

barren  windswept  country  in  which  eolian  features  are  developed 

with  exceptional  clarity  and  vigor.    From  a  point  on  the  north 

coast  about  seven  miles  east  of  the  northwest  cape  this  desert  area 

extends  in  a  southwesterly  direction  nearly  to  the  west  coast  and 

has  a  length  of  about  five  miles  and  a  width  of  about  a  half  mile. 

Its  location  as  well  as  other  salient  features  of  the  island  are  shown 

in  Figure  1. 

General  Description 

The  desert  strip  is  due  to  persistent  drifting  of  calcareous  sand 
over  the  northwest  upland  by  strong  northeast  trade  winds.  The 
sand  is  derived  from  two  or  three  miles  of  sea  beach  at  Moomomi 
on  the  north  coast.  Landward  of  this  beach  is  a  dune  belt  a  half 
mile  or  more  in  width.  The  sand  from  the  eastern  end  of  this  strip 
is  not  blown  far  inland  but  that  from  the  western  end  is  carried 
up  a  slope  which  averages  about  10  percent  or  nearly  6  degrees 
to  an  elevation  of  over  600  feet  and  thence  over  the  gradually 
declining  upland  for  nearly  three  miles  farther.  (Figure  2). 
The  writer  visited  the  region  at  a  time  when  the  trade  winds 
though  persistent  were  of  moderate  strength  and  were  moving  a 
relatively  small  amount  of  sand.  The  testimony  of  observers 
wjio  have  crossed  the  strip  during  periods  of  strong  wind  em- 
phasizes its  activity  as  a  transporting  agent  and  the  painfulness 
of  attempting  to  face  the  flying  particles  of  sand. 

There  is  a  nearly  continuous  cover  of  calcareous  sand  on  that 
part  of  the  strip  which  lies  nearest  the  beach  source  and  extending 
up  well  toward  the  highest  part.  Continuing  in  the  direction  of 
the  wind  the  sand  becomes  less  abundant  and  is  confined  to  small 


i  Published  by  permission  of  the  director  of  Bishop  Museum. 

41 


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DESERT  STRIP  OP  MOLOKAI  43 

dunes  and  linear  ridges  and  to  very  subordinate  quantities  which 
lodge  against  and  around  occasional  obstructions.  At  the  south- 
west end  of  the  strip  there  are  extensive  deposits  of  sand  filling 
the  heads  of  some  of  the  smaller  gulches  and  banked  over  the 
windward  wall  of  Kakaako  Gulch.  At  present  this  deep  gulch 
constitutes  an  obstacle  which  the  sand  does  not  pass  in  appreciable 
amounts  and  no  evidence  was  seen  by  the  writer  that  it  has  been 
extensively  blown  to  the  far  side  at  any  time  in  the  past. 


/ooo- 


Fig.  2.    Longitudinal  section  of  the  desert  strip.    Vertical  scale  exagger- 
ated four  times.    See  Fig.  1  for  location. 

Downstream  from  the  end  of  the  desert  strip  Kakaako  Gulch  is 
notable  for  the  amount  of  fine  sand  which  is  incorporated  in  its 
alluvium  and  large  quantities  of  the  sand  no  doubt  reach  the  sea 
at  the  mouth  of  this  gulch.  At  the  leeward  end  of  the  strip  the 
sand  is  buff  to  brown  in  color  and  contains  many  grains  of 
weathered  basalt  from  the  upland  in  addition  to  the  fundamental 
organic  constituents,  but  on  the  steep  slope  at  the  windward  end 
the  sand  is  whiter  and  more  largely  consists  of  debris  from  corals, 
algae,  molluscan  shells  and  foraminifera. 

In  those  parts  of  the  desert  which  are  not  wholly  covered  with 
sand  the  surface  is  commonly  abraded  to  a  level  from  one  to  five 
or  rarely  ten  feet  below  the  original  soil  layer  which  is  preserved 
in  a  few  small  boat-shaped  remnants  which  are  capped  with  sand 
mounds  and  rise  to  eight  or  ten  feet  above  the  eroded  surface. 
Immediately  below  the  old  soil  level  the  basaltic  geest  is  deep  red 
in  color  but  becomes  increasingly  lighter  colored  with  depth  and 
at  eight  or  ten  feet  is  commonly  a  mottled  yellow  or  orange  and 
gray.  Apparently  wind  abrasion  becomes  increasingly  slow  as  it 
reaches  the  more  resistent  gray  geest  and  it  has  at  no  place  un- 
covered sound  basalt  in  place.  In  a  few  places  near  the  west  end 
of  the  desert  the  surface  consists  largely  of  gray  basaltic  spheroids 
which  have  been  uncovered  by  the  wind  and  a  few  of  these  are 
isolated  at  other  points. 


44  IOWA  STUDIES  IN  NATURAL  HISTORY 

Climate  and  Vegetation 

The  climate  of  Hawaii  as  a  whole  is  characterized  by  low  annual 
and  daily  temperature  ranges,  by  the  persistence  of  trade  winds 
from  the  northeast  and  by  the  dependence  of  variations  of  rainfall 
on  the  local  geographic  factors  of  elevation  and  exposure  to  the 
prevailing  winds.  For  the  most  part  the  southwestern  and  lower 
parts  of  the  various  islands  are  dry  whereas  the  higher  parts  and 
especially  those  with  northeast  exposure  have  heavy  rainfall. 

No  climatological  data  are  available  for  the  section  of  Molokai 
in  which  the  desert  strip  is  located  but  certain  general  estimates 
can  be  made.  The  northeast  part  of  the  desert  is  exposed  to  trade 
winds  blowing  from  over  the  ocean  and  rises  fairly  steeply  to  more 
than  six  hundred  feet.  It  is  probable  from  what  is  known  of  rain- 
fall at  stations  on  the  higher,  eastern  part  of  Molokai  that  the 
rainfall  on  the  eastern  end  of  the  strip  may  be  as  great  as  20 
inches.  The  western  end,  which  is  lower  and  farther  from  the  sea 
receives  less  rainfall,  perhaps  less  than  10  inches. 

The  average  hourly  wind  velocity  is  probably  about  10  miles 
an  hour.  At  times  the  velocity  is  very  much  greater  than  this, 
probably  occasionally  reaching  40  or  50  miles  an  hour.  It  is 
probably  very  rarely  that  the  wind  departs  from  the  northeasterly 
direction  indicated  by  the  linear,  parallel-sided  form  of  the  desert 
strip.  Monthly  mean  temperatures  of  other  localities  on  Molokai 
not  far  from  the  desert  range  from  68  in  winter  to  79  in  summer 
and  the  mean  annual  temperature  for  the  desert  is  believed  to  be 
about  72  degrees. 

Practically  no  vegetation  grows  on  the  bare  surface  of  the 
basaltic  geest.  Such  plants  as  are  present  in  the  desert  are  those 
which  grow  on  the  overlying  dunes  and  sand  patches.  None  of 
these  plants  were  collected  but  a  few  have  been  tentatively  identified 
from  sketches  in  the  writer's  notebook  by  Dr.  Forest  Brown  of 
the  Bishop  Museum.  These,  the  most  abundant  elements  of  a 
somewhat  limited  flora,  were  as  follows: 

Socevola  lobelia 
Lepturus  repens 
Ipomoea  pes-caprce 
Beliotropiwm  curassavicum 
Boerhaavia  tetrandra 
Xanthium  strwmarium 

No  materal  was  obtained  which  permitted  the  identification  of 


DESERT  STRIP  OF  MOLOKAI  45 

the  shrubs  imperfectly  preserved  in  the  form  of  calcareous  casts 
of  roots  and  stems  in  some  parts  of  the  desert  strip. 

Acknowledgements 
The  writer  is  indebted  to  Mr.  Fred  Ohrt,  to  officers  of  Libby, 
McNeill  and  Libby,  and  to  Mr.  and  Mrs.  George  Cooke  for  much 
assistance  and  many  courtesies  extended  to  him  in  the  course  of 
his  studies  of  west  and  central  Molokai.  Without  the  hospitality 
with  which  he  was  met  on  all  parts  of  Molokai  it  would  have  been 
impossible  for  him  to  have  covered  a  considerable  part  of  the 
island  in  the  time  available. 

DESCRIPTION  OF  EOLIAN  FEATURES 

Larger  Features  of  the  Desert 

Sand  Formations.  Three  formations  are  to  be  distinguished  by 
their  physical  condition.  The  oldest  of  these  is  a  compactly 
cemented  eolian  sandstone  which  is  found  at  a  number  of  places 
along  the  margins  of  the  present  desert  strip  on  both  sides  and 
extending  the  width  of  the  eolian  formations  to  at  least  a  mile. 
This  sandstone  is  buff  colored  on  fresh  surfaces  and  gray  white  on 
the  weathered  surfaces.  It  shows  typical  eolian  bedding  with 
curved  planes  mostly  tangent  below  and  truncated  above.  The 
surface  of  the  formation  is  deeply  weathered  into  pits  and  channels 
forming  a  deep  euspate  profile  with  the  sharp  points  and  ridges 
pointing  upward.  This  sandstone  is  considerably  more  abundant 
on  the  north  side  of  the  strip  and  forms  together  with  some  marine 
sandstones  a  great  headland  just  west  of  the  sandy  beach  on  the 
coast. 

The  next  younger  formation  is  yellow  to  buff  dune  sand  which 
is  slightly  cemented  in  places  but  is  hardly  to  be  called  sandstone. 
This,  likewise,  is  of  typical  eolian  structure  and  lies  in  long  oval 
mounds  in  close  association  with  the  modern  sand  dunes.  These 
and  the  modern  uncemented  sand  which  is  drifted  and  lodged  here 
and  there  on  the  desert  area  constitute  the  third  formation. 

Dunes  and  Remnantal  Sand  Mounds.  The  commonest  form  of 
sand  accumulation  is  that  of  an  elongate  mound  of  which  the  wind- 
ward slope  is  somewhat  less  steep  than  that  of  the  leeward  side. 
The  mounds  are  of  all  sizes  from  a  few  yards  in  length  and  ten 
feet  high  to  several  hundred  yards  long  and  50  feet  high.     No 


46  IOWA  STUDIES  IN  NATURAL  HISTORY 

well-marked  crescentic  dunes  were  seen.  After  accumulation  has 
ceased  the  mounds,  together  with  the  underlying  pedestal  of  geest, 
are  subject  to  erosion  and  the  windward  slope  then  becomes  steep- 
est, the  side  slopes  slightly  less  steep  and  the  leeward  slope  most 
gentle  of  all.  The  relations  of  these  sand  mounds  to  the  under- 
lying surface  are  shown  in  Figure  3. 


Fig.  3.  Sketch  showing  erosion  remnants  of  geest  surmounted  by  sand 
mounds.  Note  the  distinct  line  of  the  old  surface  between  the  two.  View 
looking  northwest,  wind  moves  from  right  to  left. 

Leeward  Crowding  of  Channels.  At  several  points  where  the 
sand  from  the  desert  strip  is  drifting  into  gulches  and  small 
channels  the  windward  side  of  the  channels  is  almost  completely 
covered  with  sand  lying  at  the  angle  of  rest  of  about  30  to  31 
degrees.  The  leeward  side,  on  the  contrary,  shows  bare  basalt 
walls  and  evidence  that  the  ephemeral  streams  which  flow  in  it 
are  forced  to  the  leeward  side  by  the  continuous  infall  of  sand 
on  the  other  side.  There  can  be  little  doubt  that  over  a  period  of 
many  years  this  process  results  in  a  considerable  shifting  of  the 
channel  since  the  windward  wall  is  largely  protected  both  from 
abrasion  and  from  surface  weathering,  while  the  leeward  wall  which 
faces  to  windward  is  subject  both  to  stream  and  wind  abrasion. 

Dune  Structures.  The  two  most  prominent  types  of  structures 
in  both  the  modern  sand  and  the  older  eolian  sandstones  are  talus 
bedding  in  which  the  beds  dip  at  the  angle  of  rest  of  about  31 
degrees  and  what  may  be  called  whaleback  structure.  The  latter 
consists  of  curving  beds  which  lie  parallel  to  the  surfaces  of  the 
elongate  oval  mounds,  being  nearly  horizontal  at  the  crest  and 
dipping  increasingly  outward  toward  the  sides  and  similarly  but 
less  markedly  toward  the  ends.     This  type  of  structure  is  seen 


DESERT  STRIP  OP  MOLOKAI  47 

in  many  of  the  old  masses  of  eolian  sandstone  and  constitutes 
conclusive  proof  of  eolian  origin. 

Desert  Profiles.  In  looking  transversely  across  the  desert  strip 
from  either  side  one  is  impressed  with  the  strong  vector  character 
of  the  profiles.  This  is  especially  true  if  the  horizon  itself  is  a 
part  of  the  desert  surface.  The  windward  slopes  of  the  elevations 
are  steep  or  even  eaten  back  so  as  to  be  overhanging.  The  leeward 
slopes  are  much  more  gentle  and  in  general  continue  at  a  uniform 
angle  down  to  the  general  level.  It  is  to  be  noted  that  this  relation- 
ship between  steeper  and  gentler  slopes  is  the  reverse  of  that  shown 
by  most  sand  dunes  in  which  the  leeward  slope  of  30  to  33  degrees 
is  the  steeper.  This  difference  is  probably  due  to  the  presence  of 
a  slight  vegetal  cover  or  to  a  moderate  amount  of  cementing  in 
the  mass  which  makes  the  windward  part  more  resistant  to  the 
eroding  wind  than  is  the  case  with  freshly  deposited  material. 

Not  infrequently  the  desert  profiles  are  made  more  complicated 
by  the  presence  of  a  distinct  stratum  of  more  resistant  material, 
which  is  swept  clean  by  the  wind  and  caps  the  underlying  mush- 
room-shaped pillars.  These  usually  show  clearly  by  their  form  the 
direction  of  the  wind. 

Striated  Surfaces.  Much  of  the  desert  surface  is  strongly 
striated  and  grooved.  Except  in  a  broad  sense  it  cannot  be  said 
to  be  planed  because  there  are  many  sharp  irregularities  on  it 
and  it  thus  differs  somewhat  from  a  striated  glacial  pavement. 
There  are  slight  local  variations  in  the  direction  of  the  striaB  but 
they  fall  almost  wholly  between  S  65  W  and  S  70  W.  The  char- 
acter of  the  striated  surface  is  well  shown  in  Figure  4. 

Tilted  Blocks.  None  of  the  features  of  the  desert  is  more  strik- 
ing than  the  tilted  blocks  which  lie  on  its  surface.  These  are  most 
commonly  discoid  residuals  of  basalt  which  have  been  unearthed 
by  the  wind.  As  they  lie  on  the  surface  they  afford  considerable 
protection  to  the  underlying  geest  and  come  to  stand  on  low 
elongate  mounds  of  which  the  major  portion  extends  to  the  leeward 
in  the  form  of  a  lee  prismoid  as  described  below.  During  the  long 
period  of  erosion  from  the  time  the  upper  surface  is  exposed  until 
the  blocks  come  to  stand  above  the  surrounding  surface  they  are 
modified  by  the  formation  of  a  rain-pitted  surface  which  is  some- 
what more  nearly  plane  than  the  under  surface  and  rather  well 
separated  from  it  around  the  annular  rim  of  the  discoid.  As 
erosion  continues  the  windward  side  of  the  elongate  pillar  is  con- 


48  IOWA  STUDIES  IN  NATUKAL  HISTORY 

stantly  undermined  and  in  time  the  discoid  becomes  tilted  forward 
toward  the  wind.  In  some  instances  the  fall  is  violent  enough  so 
that  the  residual  is  displaced  and  rolls  to  some  random  position 
on  one  side  but  a  large  enough  proportion  of  them  assume  a 
definitely  oriented  and  tilted  position  to  form  a  conspicuous  element 
in  the  desert  landscape. 

After  the  discoid  has  fallen  forward  somewhat  and  lies  with  its 
pitted  surface  toward  the  wind  it  lies  enough  lower  than  it  did 
before  so  that  a  small  amount  of  material  is  deposited  a  little 
distance  ahead  of  it  and  scour  takes  place  immediately  in  front 
of,  and  behind  it.     See  Figures  5  and  6. 

Lee  Prismoids.  Closely  related  to  the  tilted  blocks  are  the 
prismoidal  pedestals  which  lie  to  the  leeward.  These  taper  to  a 
point  both  in  vertical  and  horizontal  section  and  represent  the 
form  of  least  resistance  to  a  moving  fluid  just  as  does  the  shape 
of  most  fishes  or  of  properly  constructed  boats.  The  length  is 
commonly  three  to  four  times  the  width  and  height,  the  latter  two 
being  commonly  about  equal.  Similar  prismoids  which  are  usually 
much  more  closely  controlled  by  the  shape  of  the  protecting  stone 
are  formed  of  sand  behind  small  stones  that  lie  on  the  surface. 

Lag  Materials.  All  over  the  surface  of  the  desert  one  sees  the 
effect  of  constant  sorting  by  the  wind  and  the  resulting  accumula- 
tion of  lag  materials  which  represent  for  the  time  and  place  too 
great  a  load  for  effective  removal  by  the  wind.  Some  of  these 
fragments  are  large  like  the  tilted  blocks.  Others  consist  of  small 
angular  and  sub-rounded  fragments  of  the  weathered  rock  which 
accumulate  in  low  or  protected  places  on  the  surface.  (Figure  7). 
These  range  from  a  centimeter  or  two  in  diameter  down  to  those 
of  sand  sizes. 

Chemical  Deposits 

Secondary  Calcium  Carbonate.  In  those  parts  of  the  desert 
which  are  scoured  bare  by  the  wind  there  are  seen  in  the  weathered 
basalt  many  calcareous  joint  fillings  and  nodular  masses  of  calcium 
carbonate  which  have  been  deposited  secondarily  in  the  inter- 
stices of  the  basalt  mass.  The  latter  appear  in  some  places  to 
fill  the  spaces  in  old  masses  of  basalt.  Commonly  these  are  some- 
what more  resistant  to  the  wind  than  the  basalt  geest  and  stand 
above  the  surrounding  surface  as  slight  mounds. 

Plant  Moulds.     It  is  impossible  to  tell  how  much  of  the  lime  in 


DESERT  STRIP  OF  MOLOKAI  49 

the  above-mentioned  joint  fillings  has  come  from  the  basalt  in  the 
process  of  weathering  and  how  much  from  overlying  masses  of 
calcareous  dune  sand  which  have  at  one  time  or  another  occupied 
every  part  of  the  desert  strip.  At  any  rate  in  places  which  have 
been  recently  abandoned  by  the  sand  formations  there  are  abund- 
ant moulds  of  plant  stems  and  roots.  These  are  commonly  still 
standing  with  additional  broken  parts  strewn  over  the  surface. 
Not  uncommonly  the  stem  moulds  stand  above  an  old  geest  surface 
with  parts  of  the  sand  formations  still  lying  on  it  and  the  root 
moulds  eroded  at  the  margin  of  the  geest  surface  and  lying  below 
it.  In  these  places  a  few  prostrate  branches  lie  in  place  close  to 
the  geest  surface  and  the  moulds  of  what  appear  to  have  been 
extensive  vine  systems  cover  the  same  surface.  These  are  merely 
rough  external  moulds  of  the  plant  parts  and  show  no  structure. 
The  more  compact,  travertine-like  part  lies  next  the  inner  wall  and 
the  outer  parts  are  more  porous  and  carry  loosely-cemented  layers 
of  the  sand  which  formerly  surrounded  them.  It  appears  that 
the  cementing  was  achieved  by  waters  carrying  calcium  bicarbon- 
ate which  passed  downward  through  the  sand  formations  as  they 
became  stabilized  and  found  the  most  favorable  routes  along  the 
stems  of  plants.  It  is  possible  also  that  some  chemical  reaction 
between  the  decaying  stems  and  the  groundwater  solutions  favored 
deposition  of  the  calcium  carbonate.  In  places  at  least  the  calcium 
carbonate  which  appears  in  the  superficial  layers  of  the  geest  must 
have  come  from  the  leaching  of  the  overlying  sand  formations. 

Abrasion  Features 

Rock  Striation.  The  striation  of  the  geest  surface  has  been 
described.  In  addition  at  various  places  in  the  desert  strip  but 
particularly  toward  the  west  end  where  rock  fragments  which 
retain  a  fixed  position  are  more  abundant  the  rock  surfaces  are 
distinctly  striated  by  the  action  of  the  wind-drifted  sand.  The 
striation  is  best  shown  on  the  somewhat  weathered  surfaces  of 
basaltic  spheroids  which  are  partly  uncovered  by  the  wind  but 
are  still  in  place  and  subject  to  persistent  abrasion  in  one  position. 
In  such  favorable  situations  a  few  rocks  appear  to  have  been  cut 
away  by  abrasion  to  the  extent  of  several  millimeters  or  perhaps  a 
centimeter  or  two.  The  resulting  surfaces  are  rounded  in  a 
direction  transverse  to  the  wind  but  tend  to  be  composed  of 
straight  line  elements  parallel  to  the  wind  and  rising  at  angles 


50  IOWA  STUDIES  IN  NATURAL  HISTORY 

of  ten  to  twenty  degrees  toward  the  leeward.  The  striate  char- 
acter of  the  surfaces  is  fairly  clear  but  differs  from  a  glacially 
striated  surface  in  that  the  whole  surface  is  made  up  of  fine 
groovings  rather  than  of  a  planed  surface  marked  with  scratches. 
The  direction  of  the  individual  striae  is  subject  to  slight  variation 
particularly  where  harder  nodules  or  olivine  crystals  in  the  basalt 
project  and  deflect  the  wind  currents.  Similar  results  are  pro- 
duced by  small  pits  and  vesicles  in  the  surface,  from  which  the 
striae  radiate  in  a  narrow  spray  or  fan-shaped  pattern.     (Figure  8.) 

Etching.  Comparatively  little  differential  abrasion  or  etching 
takes  place  in  the  basalt  under  the  action  of  the  wind  because  the 
rock  for  the  most  part  is  relatively  uniform  in  hardness.  In  a 
few  places  olivine  crystals  are  left  protruding  as  the  surrounding 
rock  is  worn  away. 

Polishing.  A  few  of  the  pieces  of  dike  rock  which  have  been 
dropped  by  the  Hawaiians  are  well  smoothed  and  slightly  polished 
but  by  far  the  largest  part  of  the  abraded  surfaces  are  dull.  It 
is  probable  that  the  minerals  in  the  basalt  are  not  favorable  to 
receiving  and  retaining  a  bright  polish.  The  fragments  of  sec- 
ondary calcium  carbonate  which  are  found  on  some  parts  of  the 
desert  strip  are  moderately  well  polished  and  the  sand  itself  is 
commonly  composed  of  bright,  smooth  grains. 

Windward  Frosting.  Some  of  the  blocks  of  rock  which  are 
striated  on  the  top  and  lateral  sides  show  on  their  windward  sides 
a  rougher,  lighter-colored  and  unstriated  surface  which  may  be 
described  as  frosted.  This  surface  appears  to  be  due  to  the 
impingement  of  grains  of  sand  where  the  wind  blows  so  directly 
against  it  that  the  sand  is  not  deflected  wholly  around  the  sides 
or  over  the  top  to  produce  the  striated  type  of  surface. 

Sand  Blasted  Pebbles.  In  a  situation  such  as  that  being 
described  one  expects  to  find  sand  blasted  pebbles  but  actually 
they  are  surprisingly  rare.  A  few  are  found  which  bear  the  marks 
of  considerable  abrasion  and  have  forms  approaching  to  the  two 
or  three-angled  sharp-crested  einkanter,  dreikanter,  etc.,  which  are 
found  elsewhere.  None  of  these  has  strongly  carved  facets  or 
strikingly  sharp  edges. 

Inferiority  of  Abrasion  by  Calcareous  Sand.  The  abundance  of 
features  attributable  to  the  blowing  of  the  wind  combined  with  the 
restriction  of  the  marked  effects  to  the  weathered  geest  and  to 
the  superficial  layers  of  harder  parts  of  the  basalt  leads  to  the 


DESERT  STRIP  OF  MOLOKAI  51 

conclusion  that  the  calcareous  sand  must  be  vastly  inferior  as  an 
abrasive  agent  to  the  quartz  sand  which  is  common  in  most  regions 
where  wind  abrasion  is  impressive.  There  would  perhaps  be  little 
difference  in  the  work  of  quartz  and  calcareous  grains  of  the  same 
shape  on  such  material  as  the  softer  layers  of  the  geest.  On  the 
harder  rock  fragments  which  lie  on  the  desert  there  is  little  doubt 
that  the  calcareous  sand  is  confined  in  its  effects  to  moderate 
abrasion  and  slow  polishing  where  quartz  under  similar  vigorous 
wind  action  would  achieve  a  much  more  vigorous  carving  of  the 
rocks. 

Discoid  Shapes.  Many  of  the  larger  basalt  fragments  which 
lie  on  the  surface  of  the  desert  strip  are  the  cores  of  units  of 
spheroidal  weathering.  Some  of  these  are  nearly  spherical  but 
the  bulk  of  them  are  oblately  spheroidal  or  lenticular  in  form  and 
show  a  considerable  differentiation  between  the  top  and  bottom 
surfaces.  It  is  not  to  be  understood  that  the  cross  section  of  these 
as  viewed  in  the  direction  of  the  short  axis  is  always  circular. 
There  is  considerable  variation  but  a  strong  tendency  toward  the 
typical  form  which  is  here  described.  The  upper  surface  of  the 
two  is  the  least  convex  and  is  commonly  pitted  from  the  weathering 
which  is  favored  by  retention  of  rain  water  in  initial  hollows  of 
the  surface.  In  the  most  marked  examples  this  pitting  covers  the 
entire  upper  surface,  the  pits  being  separated  by  relatively  sharp 
crested  rims.  The  lower  surface  is  a  convex  one  more  nearly  of 
the  curvature  of  the  annular  profile  and  is  developed  on  more 
deeply  weathered  basalt.  On  the  upper  surface  the  weathering 
is  cleaner  and  the  basalt  more  nearly  fresh.  Between  the  two  sur- 
faces is  a  more  or  less  distinct  annular  rim  which  represents  the 
surface  of  the  ground  at  the  time  when  the  distinctive  form  was 
developed  with  the  discoid  block  in  a  half -buried  position.  See 
Figure  5. 

Surface  Markings  on  Sand 

Ripple  Marks.  Ripple  marks  are  common  on  the  tops  and  sides 
of  the  dunes  and  on  the  sand  of  the  beach.  Changes  in  the  direc- 
tion or  strength  of  the  wind  commonly  lead  to  alteration  of  the 
ripple  marks,  which  as  a  consequence  show  the  relics  of  one  series 
being  replaced  by  another.  At  one  place  were  some  large  ripple 
marks  of  about  a  foot  across,  the  crests  of  which  had  been  planed 
off  by  the  wind  and  made  the  site  of  a  smaller  series  of  marks. 


52 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Swing  Marks.  These  are  common  in  the  sandy  parts  of  the 
desert  as  they  probably  are  in  sandy  regions  in  all  parts  of  the 
world.  So  far  as  the  writer  knows  no  name  has  been  applied  to 
them  and  the  name  swing  mark  appears  to  be  as  good  as  any. 
They  are  formed  by  the  swinging  to  and  fro  or  round  and  round 
of  stems  or  roots  of  plants  which  are  anchored  at  one  or  both  ends. 
The  commonest  form  is  produced  by  a  grass  stem  which  is  broken 
over  at  the  surface  of  the  sand  but  not  quite  broken  off.  As  this 
lies  on  the  sand  the  wind  sweeps  it  back  and  forth  around  the 
attachment  pivot  making  marks  on  the  sand  in  the  form  of  a  sector 
of  a  circle.  If  it  swings  through  the  full  circle  a  target-like  series 
of  marks  is  the  result.  A  more  unusual  form  is  produced  when  a 
slender,  flexible  root  which  is  anchored  at  both  ends  is  set  in 
motion.  This  produces  a  shaded  double  convex  lenticular  pattern. 
See  Figure  10. 


Fig.  10.  Sketch  of  different  forms  of  swing  marks 
developed  on  sand  by  wind-swung  stems  and  roots  of 
vegetation. 


Pebble  Roll  Marks.  These  are  irregular  discontinuous  marks 
similar  to  those  made  by  rolling  a  large  snowball  and  are  produced 
by  the  rolling  of  any  small  objects  down  steep  slopes  of  the  dunes. 

Columnar  Cliffs  in  Sand.  These  are  produced  by  gravity  sap- 
ping wherever  the  wind  or  any  other  agent  has  produced  a  vertical 
wall  of  a  few  inches  or  feet  in  sand  which  is  wet  or  slightly 
cemented.  The  columnar  configuration  is  produced  by  the  faith- 
ful reproduction  vertically  of  every  irregularity  in  the  lower  part 
of  the  bank.  At  the  bottom  of  such  a  columnar  bank  is  commonly 
a  series  of  merging  talus  cones  made  up  of  the  material  derived 
from  the  bank. 


DESERT  STRIP  OF  MOLOKAI  53 

Tracks  of  Animals.  Among  the  ephemeral  features  of  the  desert 
strip  are  the  tracks  of  various  animals.  All  those  which  are  plain 
are  in  the  sand  since  only  the  cattle  and  horses  are  heavy  enough 
to  make  a  recognizable  track  in  the  geest  surface.  The  tracks  of 
cattle  wfere  most  abundant  but  those  of  horses,  goats,  cats,  mice, 
birds,  and  various  insects  were  noted. 

Human  Relics 

Stone  Implements.  The  ancient  Hawaiians  were  skillful  work- 
ers of  stone  and  many  evidences  of  their  work  may  be  found  in 
the  desert  strip  at  the  present  time.  The  stone  implements  are 
not  now  so  abundant  as  they  once  were  but  a  few  may  still  be 
collected.  The  most  common  implement  is  the  adze  which  was 
made  of  very  compact,  fine-grained  dike  rock  by  chipping  and 
rubbing.  The  bulk  of  those  seen  by  the  writer  were  blanks  on 
which  the  larger  part  of  the  necessary  chipping  had  been  done 
but  none  of  the  rubbing.  There  is  a  close  association  between 
the  adze  blanks  and  all  the  other  relics  described  in  this  section. 
They  are  found  strewn  over  small  areas  of  fifty  or  a  hundred  feet 
in  diameter.  Commonly  they  are  close  to  the  base  of  one  of  the 
low  sand  mounds  which  stand  on  remnants  of  the  original  geest 
surface.  In  a  few  places  the  relics  lie  on  a  geest  surface  and 
appear  to  have  been  covered  with  sand  and  then  re-excavated  by 
the  wind.  There  is  no  convincing  evidence  however  that  the  bulk 
of  the  Hawaiian  relics  were  left  on  the  desert  strip  at  a  time  prior 
to  the  formation  of  the  greater  part  of  the  modern  sand  dunes. 
It  may  well  be  that  some  were  but  the  most  of  the  material  which 
lies  about  is  probably  not  more  than  two  or  three  hundred  years 
old. 

Far  more  abundant  than  the  adzes  and  rough  blanks  axe  the 
chips  and  spalls  which  were  produced  in  working  them.  These  are 
identifiable  both  by  their  lithologic  characters  and  the  artificial 
shapes  and  freshness  of  some  of  their  surfaces.  It  is  possible  that 
a  few  of  the  chips  are  from  local  rock  of  the  discoid  residuals  but 
the  majority  come  from  a  series  of  dikes  near  the  coast  north  of 
the  desert.  There  is  a  fairly  distinct  train  of  this  material  by 
which  it  may  be  traced  back  from  the  desert  to  the  quarry  from 
which  the  Hawaiians  took  it. 

It  is  probable  that  the  activity  of  the  Hawaiian  stone  workers 
in  this  area  extended  over  a  period  of  many  generations  for  some 


54  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

of  the  chips  show  at  least  two  generations  of  etched  surfaces.  The 
first  appears  to  have  been  developed  on  fragments  of  the  adze  rock 
which  were  dropped  by  the  earlier  carriers.  Chips  were  then 
broken  off  these  pieces  as  they  were  utilized  by  later  generations 
for  adzes.  These  chips  are  in  turn  etched  by  the  wind-driven  sand 
on  the  fresher  faces.  There  is  a  distinct  difference  between  the 
older  and  newer  etched  faces. 

Marine  Shells.  Shells  of  pelecypods  of  various  species  and  of 
several  species  of  gastropod  are  scattered  near  the  artifact  ma- 
terials. Most  of  these  probably  were  used  for  food  but  there  is  one 
exception  which  furnishes  clear  evidence  of  human  agency  in 
transporting  them  from  the  sea  coast.  These  are  the  cowrie  shells 
(Cyprcea  tigrina)  which  are  used  as  bait  in  squid  fishing.  These 
invariably  have  one  side  of  the  opening  chipped  out  as  is  necessary 
to  admit  the  straight  stick  which  is  inserted  between  the  sinker 
proper  and  the  shell. 

Smoothing  Pebbles.  Small,  very  smooth  pebbles,  probably  of 
beach  origin  in  the  first  place,  are  used  as  smoothing  stones  in 
rubbing  and  polishing  articles  of  wood  and  others  were  probably 
used  in  cooking  small  birds.  All  these  are  abundant  round  the 
artifact  sites.  In  addition  to  these  small  pebbles  there  are  a  num- 
ber of  large  beach  cobbles  of  a  somewhat  elongate  form  and  20  to 
40  centimeters  in  their  longest  diameter.  These  are  rather  symmet- 
rical and  were  probably  used  for  hammering  and  as  anvdls. 
(Figure  9). 

Coral  Files.  A  few  fragments  of  rough  coral  which  are  shaped 
to  a  triangular  wedge  form  are  the  files  used  in  sharpening  fish- 
hooks and  in  cutting  away  other  materials.  Near  the  various 
relics  mentioned  in  a  few  places  were  found  the  remains  of  small 
fire  places  in  which  a  few  fragments  of  charcoal  are  still  to  be 
found. 

HISTOEY  OF  THE  DESEET  STEIP 

Origin 

The  desert  strip  owes  its  existence  to  the  action  of  the  wind- 
driven  sand  in  killing  vegetation  by  abrasion  and  by  burial. 
Though  the  west  end  of  Molokai  is  dry  and  shows  at  various  other 
localities  the  evidence  of  much  work  by  the  wind,  the  extreme 
development  of  strongly  oriented  eolian  features  is  confined  to 
the  strip  which  extends  in  a  straight  line  with  well  defined  parallel 


DESERT  STRIP  OF  MOLOKAI  55 

sides  across  the  upland.  The  sand  is  derived  from  the  beach  at 
Moomomi  and  is  being  formed  today  by  wave  action  on  the  small 
living  reef  which  lies  off  shore  at  this  point.  At  the  present  time 
very  little  sand  serves  to  keep  vegetation  down  for  the  strip  is 
now  so  deeply  abraded  that  the  exposed  deeper  geest  is  relatively 
unfavorable  for  plant  growth. 

History 

Little  is  known  which  enables  one  to  make  an  estimate  of  the 
age  of  the  desert  strip.  The  great  mass  of  eolian  sandstone  which 
forms  a  headland  just  west  of  Moomomi  beach  was  probably 
formed  when  the  coast  was  less  eroded  and  the  land  extended 
several  hundred  yards  farther  north  than  now  since  it  could  hardly 
have  been  formed  by  the  blowing  of  sand  from  a  beach  having 
the  location  of  the  present  one.  The  larger  part  of  the  old  well- 
cemented  sandstone  on  the  upland  lies  to  the  north  of  the  present 
strip  and  likewise  suggests  that  sand  had  at  an  earlier  time  better 
access  to  the  northern  upland  than  now.  Considering  the  amount 
of  coastal  abrasion  which  appears  to  have  taken  place  and  the 
cementing  and  weathering  of  the  sandstone  the  origin  of  the 
desert  strip  may  well  be  dated  some  tens  of  thousands  of  years  ago. 

At  any  rate  it  is  clear  that  during  the  earlier  part  of  its  history 
it  extended  farther  both  to  the  north  and  also  to  lesser  extent 
farther  to  the  south  than  it  does  at  present.  Whether  both  of  these 
greateT  extensions  took  place  at  the  same  time  so  that  the  desert 
was  appreciably  wider  than  now  is  not  known  but  is  thought  to  be 
probable.  It  is  difficult  to  tell  whether  the  desert  strip  was  so 
long  and  continuous  toward  the  southwest  in  the  earlier  part  of 
its  history  as  it  now  is  because  the  southwest  end  of  the  desert 
once  reclaimed  would  not  carry  as  permanent  marks  of  its  old 
desert  character  because  of  the  lesser  quantity  of  sand  which  lies 
on  it.  Evidence  of  a  broader  desert  strip  are  confined  to  the 
northeast  slope  and  the  summit  portion  and  do  not  continue  far 
to  the  southwest.  With  the  abandonment  of  active  sand  drifting 
in  the  sections  marginal  to  the  present  strip  the  desert  assumed 
a  regimen  which  was  essentially  that  of  today.  Probably  the 
earlier  part  of  the  history  including  the  cementing,  weathering  and 
erosion  of  the  oldest  of  the  sand  formations  was  very  much  longer 
than  the  later  part  during  which  the  sand  has  been  confined 
essentially  to  the  present  strip. 


56  IOWA  STUDIES  IN  NATUEAL  HISTORY 

During  this  later  period  two  fairly  distinct  formations  of  sand 
have  been  formed.  So  far  as  known  only  the  latter  is  contem- 
poraneous with  Hawaiian  occupation  of  the  island.  The  locations 
of  the  fire  places  and  other  groups  of  relics  are  such  as  to  suggest 
that  the  topography,  even  to  the  details  of  the  sand  mound  rem- 
nants and  tilted  blocks,  was  substantially  the  same  when  the 
Hawaiians  left  them.  The  more  recent  activities  of  stone  working 
Hawaiians  are  no  more  than  100  years  in  the  past  but  the  testimony 
of  different  stages  in  the  etching  of  artifact  chips  is  to  the  effect 
that  the  earlier  Hawaiian  work  here  may  be  several  hundred  or 
a  thousand  years  old. 

Importance  of  Wind  Erosion 

We  may  therefore  conclude  that  the  formation  of  some  of  the 
smaller  features  of  the  desert  such  as  the  sand-covered  geest  rem- 
nants or  even  the  excavation  and  tilting  of  the  tilted  blocks  may 
represent  the  work  of  several  hundred  years.  The  average  amount 
of  material  removed  by  wind  erosion  in  the  desert  was  not  ascer- 
tained with  any  degree  of  precision  but  by  way  of  illustration  we 
may  take  five  feet  as  a  reasonable  figure.  If  the  total  age  of  the 
desert  strip  is  estimated  at  50,000  years  this  will  amount  to  an 
average  removal  of  one  foot  in  10,000  years.  The  principal  value 
which  attaches  to  a  rough  estimate  of  this  sort  which  may  well 
vary  two  or  three  fold  either  way  from  the  truth  is  to  indicate 
the  relation  of  wind  erosion  under  local  and  very  favorable  con- 
ditions to  the  rate  of  stream  erosion.  The  figure  given  indicates 
that  the  rate  of  wind  erosion  may  locally  and  under  very  favorable 
conditions  approach  the  average  rate  of  reduction  of  large  con- 
tinental masses  by  streams.  The  special  conditions  here  with  the 
continuous  supply  of  sand  which  enters  in  no  way  into  the  com- 
putation of  quantities  removed  must  indicate  the  very  slight 
quantitative  importance  of  wind  erosion  in  general  as  compared 
to  stream  erosion. 

At  the  same  time  where  conditions  are  relatively  unfavorable 
to  stream  erosion  wind  erosion  is  capable  of  producing  a  large 
series  of  striking  and  typical  topographic  forms  and  details  which 
quite  dominate  the  landscape.  At  no  place  is  this  more  strikingly 
shown  than  in  one  such  as  described  above  where  strong  trade 
winds  blow  persistently  from  one  direction  throughout  the  year. 


1 

§§11 

:--"'  ^,    ^''■w;'*-!.^,::':-'''.?-i,^«iiir"Aif 

S^sl*;.:  ;;:;■ 

;«S 

■■--.'■■■■■■■..■    ,,„.,„„■        <■■■              ■;'■:...<:      -^      >i;  «^s:-i;:*f^,«:,^£s:^l^^.^»:' 

it^HS 

•igj^*^ 

'^fcl^-5 

p!^^&*^» 

j^feff 

^sV^- 1. 

SESSK4.  JE^VBBW^vi^fiu 1^ 

Fig.  4.    Detail  of  striated  horizontal  surface  of  the  desert.     Part  shown 
i  about  two  feet  long.    Direction  of  wind  is  from  left  to  right. 


i 

8llpllpli 

^^t*, 

'.■-.■:' 

1 

illiiM 

llpiill 

fe;:::.:::::Z::MSi^' 

:  #«ir wm 

y:Mmm:m 

w^::,0m 

felK 

•-* 

iiiifP^ 

Fig.  5.     View  of  tilted  block  showing  discoid  form  and  pronounced  annu- 
lar rim  between  upper  and  lower  surfaces. 


Fig.  6.     View  of  tilted  blocks  showing  rude  discoid  forms,  pitted  upper 
surfaces  and  elongate  pedestals. 


Fig.  7.  Detail  of  desert  surface  showing  cross  section  of  spheroidal  struc- 
ture of  basaltic  geest  which  lies  beneath.  Loose  fragments  on  the  surface 
are  loosened  by  plucking  and  uncovering  by  the  wind  and  then  become 
abraded  and  worn  down  to  the  harder  stone. 


Fig.  8.     Detail  of  abraded  and  striated  rock  surfaces.     Pencil  points  in 
direction  wind  moves. 


Fig,  9.     Detail  of  desert  surface  showing  large  rounded  beach  pebble  and 
artifact  chips  left  by  Hawaiian  natives. 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  5 


PAPERS  ON  THE  PRAIRIE 


by 

B.  Shimek 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


THE  PERSISTENCE  OF  THE  PRAIRIE 

B.  Shimek 

The  belief  that  the  prairie  flora  will  not  return  if  the  prairie  is 
broken  is  widely  prevalent.  With  it  is  linked  the  further  belief 
that  the  prairie  flora  is  not  a  climax  flora,  but  that  it  represents 
a  transition  stage  which  would  culminate  in  a  forest  with  the  cessa- 
tion of  prairie  fires,  were  it  not  for  the  disturbance  of  the  prairie 
surface  by  cultivation. 

It  is  true  that  the  prairie  yields  readily  to  cultivation.  The 
breaking  of  the  prairie  turf  is  sufficient  to  cause  most  of  the  prairie 
plants  to  disappear  from  the  broken  surface,  but  there  is  abundant 
evidence  to  show  that  it  requires  continued  cultivation  to  keep 
them  out.  Their  return  is  rather  slow  and  is  preceded  by  a  transi- 
tional mixture  of  species,  but  it  is  quite  certain,  provided  man  does 
not  interfere. 

Comparatively  little  of  the  native  prairie  remains  in  Iowa.  A 
few  unbroken  tracts  are  still  scattered  about  over  the  state,  espe- 
cially in  the  northwestern  quarter,  but  even  these  have  been  dis- 
turbed more  or  less  by  pasturing  and  cutting.  The  purest  rem- 
nants of  the  prairie  are  often  found  along  the  right  of  way  of  the 
older  railways  which  entered  the  territory  before  the  original 
prairie  was  broken,  and  they  give  the  most  striking  illustration  of 
the  persistence  of  prairie  where  it  remains  undisturbed,  even  in 
such  narrow  strips  as  those  here  noted. 

In  this  state  the  prairie  flora  survives  in  these  unbroken  areas, 
and  also  in  neglected  corners,  along  fence-rows,  in  partially  pas- 
tured areas,  and  on  more  or  less  undisturbed  open  grounds  gen- 
erally. Much  of  this  native  flora  was  also  formerly  preserved  along 
the  public  highways,  but  this  is  rapidly  disappearing  with  the  wid- 
ening of  the  driveways  on  the  primary  roads  and  the  enforcement 
of  the  unwise  undiscriminating  weed-laws  of  the  state  along  sec- 
ondary roads. 

These  various  remnants  of  the  prairie  flora  are  widely  scattered, 
and  they  are  amply  sufficient  to  re-seed  all  suitable  areas.  No 
native  prairie  species  has  entirely  disappeared,  though  all  have 
been  much  reduced,  and  in  a  few  cases  almost  exterminated.  Per- 
haps the  most  striking  of  the  latter  kind  is  that  of  one  of  the  blaz- 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

ing  stars,  Liatris  squarrosa,  once  abundant  on  the  prairies  of  Iowa, 
but  now  very  rare.  The  buffalo  grass,  Buchloe  dactyloides,  never 
common  in  Iowa,  is  now  almost,  if  not  entirely,  extinct.  Other 
species  have  become  very  rare,  but  on  the  whole  the  original  prairie 
flora  is  practically  preserved,  and  if  given  an  opportunity  it  would 
no  doubt  again  spread  over  a  large  part  of  the  state.  It  has  even 
advanced  into  many  places  which  were  formerly  covered  with  forest, 
but  in  such  cases  the  prairie  flora  persists  only  when  the  return  of 
the  forest  is  artificially  prevented.  Numerous  illustrations  of  this 
fact  are  found  where  the  railway  right  of  way  has  been  kept  cleared 
through  the  groves  which  broke  the  monotony  of  the  prairies  in 
Iowa.  In  such  cases  the  prairie  usually  invades  the  denuded  areas, 
in  which  it  will  probably  persist  so  long  as  the  right-of-way  is  kept 
clear.  Some  years  ago  the  writer  reported1  a  similar  case,  where 
prairie  took  possession  of  the  borders  of  a  road  cut  through  the 
forest  north  of  Homestead,  Iowa,  and  periodically  cleared  for  many 
years.  The  borders  of  this  road  have  not  been  cleared  since,  except- 
ing as  the  driveway  has  been  widened  and  graded,  and  most  of  the 
prairie  flora  is  being  crowded  out  by  the  rapidly  returning  forest 
flora. 

For  many  years  the  writer  has  been  engaged  in  making  field-ob- 
servations on  the  development  and  disappearance  of  prairie  floras, 
and  this  paper  contains  an  account  of  such  changes  in  twro  widely 
separated  areas,  the  result  in  each  case  being  the  return  of  the 
prairie  flora  to  a  disturbed  surface. 

The  first  of  these  areas  extends  along  the  Chicago,  Rock  Island 
and  Pacific  Railway  between  Wilton  and  Summit,  in  Muscatine 
County,  Iowra,  and  illustrates  both  the  persistence  of  the  prairie 
flora  on  undisturbed  surfaces,  even  when  narrow,  and  the  possi- 
bility of  the  return  of  this  flora  to  disturbed  areas. 

The  second  is  a  more  limited  area  adjoining  Mason  City,  Iowa, 
and  illustrates  a  result  of  the  invasion  of  a  formerly  cultivated  area 
by  the  prairie  in  apparent  competition  with  a  forest  flora  on  the 
opposite  side. 

I.     THE  WILTON-SUMMIT  AREA 

This  area  embraces  the  right  of  wTay,  averaging  less  than  one 

hundred  feet  in  total  width,  along  the  Wilton  and  Muscatine  branch 

of  the  Chicago,  Rock  Island  and  Pacific  Railway,  beginning  at  a 

point  nearly  half  a  mile  south  of  Summit  and  extending  to  the  for-. 


*An  artificial  prairie. — This  Bulletin,  vol.  VI,  no.  4;   1913. 


PERSISTENCE  OP  THE  PRAIRIE  5 

est  border  south  of  Wilton,  a  total  distance  of  about  five  miles. 
The  area  is  shown  within  the  three  two-mile  stretches  represented 
in  Plate  I. 

This  line  was  constructed  in  the  year  1854,  when  most  of  the 
surrounding  region  was  uncultivated,  and  strips  of  the  original 
prairie  still  remain  within  the  right  of  way.  The  portion  of  the 
line  here  considered  traverses  a  high  prairie,  lying  entirely  within 
a  gently  undulating  Illinoian  drift  plain  (Plate  II,  fig.  1).  In  the 
report  on  Muscatine  County,  Udden2  represents  this  area  as  loess- 
covered,  but  there  is  no  loess  in  the  part  of  the  plain  under  con- 
sideration. Most  of  the  area  is  covered  with  a  fertile  prairie  loam, 
but  the  ridges  often  show  some  sand, — evidently  small  outliers  of 
the  old  sand-dune  area  bordering  the  Cedar  River  valley  to  the 
west. 

The  undulating  character  of  the  surface  is  well  shown  along  the 
railway,  necessitating  a  succession  of  rather  low  cuts  and  fills,  as 
shown  in  Plate  I.  The  depressions  are  more  or  less  swampy,  and  are 
covered  with  a  hydrophytic  flora,  while  the  better  drained  areas  are 
occupied  by  a  more  or  less  xerophytic  prairie  flora. 

The  road-bed  and  the  ditches  on  either  side  occupy  about  25  feet 
of  the  width  of  the  right  of  way,  but  in  some  places  there  has  been 
a  further  disturbance  of  the  surface  by  the  deeper  cuts  (which  ex- 
tend to  the  edge  of  the  right  of  way  in  several  places),  by  the  heap- 
ing up  of  ridges  of  earth  excavated  from  the  cuts,  or  by  additional 
grading  to  secure  earth  for  the  fills.  Excepting  for  these  interrup- 
tions, and  those  caused  by  the  intersecting  public  highways  at  in- 
tervals of  a  mile,  the  outlying  strips  on  both  sides  of  the  right  of 
way  form  continuous  belt  transects  of  the  original  prairie  about 
five  miles  in  length  and  reaching  a  width  of  more  than  thirty  feet 
in  the  widest  place. 

The  entire  right  of  way  therefore  presents  three  more  or  less 
distinct  surface  types:  1.  The  outlying  original  prairie  belts  on 
either  side,  with  the  native  prairie  flora  well  preserved.  2.  The 
areas  disturbed  early  in  the  history  of  the  road  by  cuts,  or  ridges 
thrown  up  from  the  cuts,  but  subsequently  practically  undisturbed 
for  many  years,  to  which  the  prairie  flora  has  fully  returned. 
3.  The  road-bed  proper  with  its  ballast  and  the  bordering  ditches, 
all  of  which  are  subjected  to  frequent  disturbances  in  connection 
with  the  repair  and  maintenance  of  the  railway.  The  flora  of  this 
section  is  mixed,  and  contains  a  large  element  of  introduced  weeds. 


2Iowa  Geological  Survey,  vol.  IX;  1899. 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

1.     The  Original  Prairie 

The  remarkable  tenacity  of  the  prairie  flora  is  well  illustrated  in 
these  belt  transects  of  unbroken  prairie.  For  many  years  the  ad- 
joining fields  have  been  under  cultivation,  and  both  fields  and 
fence-rows  have  produced  weeds  abundantly.  On  the  inner  side 
each  belt  transect  has  been  in  contact  with  the  middle  roadbed 
belt,  with  its  numerous  weeds  and  other  introduced  plants.  (See 
more  detailed  discussion  of  the  flora  of  this  belt  under  section  3, 
following.)  Yet  few  introduced  plants  have  been  able  to  estab- 
lish themselves  in  the  belts  of  unbroken  prairie,  and  most  of  these 
in  very  small  numbers.  The  blue  grass,  Poa  pratensis,  seems  to 
make  the  most  successful  invasions,  but  does  not  establish  a  sod  to 
the  exclusion  of  the  native  prairie  plants,  and  it  is  probable  that 
its  success  is  due  in  large  part  to  the  frequent  introduction  of  new 
seed.  Poa  compressa  is  less  frequent,  and  usually  occurs  in  areas 
which  have  been  somewhat  disturbed.  It  is  possible  that  this  was 
a  native  of  the  drier  prairies.  Two  other  introduced  plants  oc- 
casionally gain  a  foothold,  but  usually  in  very  small  numbers. 
They  are  timothy,  Phleum  pratense,  which  is  also  extensively  cul- 
tivated on  the  farms,  and  asparagus,  Asparagus  officinalis,  which 
is  also  commonly  cultivated.  In  the  latter  case  birds  which  feed  on 
the  berries  are  evidently  responsible  for  the  wide  dispersal  of  the 
seeds. 

Aside  from  these  four  by  no  means  conspicuous  invaders  these 
belts  contain  a  typical  prairie  flora  where  the  surface  has  not  been 
disturbed,  or  where  it  does  not  become  very  wet  during  the  early 
part  of  the  season. 

Where  there  have  been  minor  local  disturbances  of  the  prairie 
turf  by  gophers,  groundhogs,  slight  excavations  for  earth  needed 
for  ballasting  the  track,  etc.,  the  disturbed  surface  is  usually 
promptly  invaded  by  a  mixed  group  of  plants  consisting  in  part 
of  introduced  foreign  weeds  and  in  part  (or  originally,  and  some- 
times even  now  entirely)  of  certain  native  prairie  plants  which 
now  also  invade  cultivated  grounds  and  pastures,  and  which  were 
evidently  the  "weeds"  of  the  original  prairie  which  took  posses- 
sion of  all  disturbed  surfaces.  These  weeds  are  usually  soon  fol- 
lowed by  the  climax  flora  of  the  prairie.  They  are  discussed  in 
section  2,  Restored  Prairie. 

The  continuity  of  the  prairie  belts  is  also  interrupted  by  the  low 
areas  which  alternate  with  the  higher  places  indicated  in  Plate  I 


PEESISTENCE  OF  THE  PRAIRIE 


by  railway  cuts.  Some  of  these  depressions  are  creek-beds,  but  most 
of  them  are  undrained.  Their  flora  is  that  which  usually  char- 
acterizes low  areas  in  the  prairie  region  which  are  wet  during  at 
least  a  part  of  the  year.  There  is  no  larger  body  of  water  in  this 
area,  and  none  of  the  depressions  retain  water  during  the  average 
season,  hence  the  flora  is  marsh  rather  than  aquatic.  The  follow- 
ing plants  of  this  type  were  noted : 

Typha  latifolia 
Panicum  dichotomiflorum 
Leersia  oryzoides 


Agrostis  alba 
Calamagrostis  canadensis 
Glyceria  nervata 
Elymus   virginieus 
Eleocharis  palustris 
Seirpus  fluviatilis 
Seirpus  atrovirens 
Seirpus  cyperinus 
Carex  vulpinoidea 
Carex  Sartwellii 
Carex  lanuginosa 
Acorus  calamus 
Juncus  interior 
Iris   versicolor 
Habenaria  leucopheea 
Salix  longif  olia 
Salix  cordata 


Polygonum  Muhlenbergii 
Rumex   brittanica 
Rumex  mexicanus 
Radicula  palustris 
Penthorum   sedoides 
Saxifraga  pennsylvanica 
Lythrum  alatum 
Ludwigia   polycarpa 
(Enothera    pratensis 
Cicuta   maeulata 
Steironema   ciliatum 
Asclepias    incarnata 
Verbena  hastata 
Stachys  palustris 
Galium  asprellum 
Aster   salicifolius 
Silphium   perfoliatum 
Bidens  frondosa 
Bidens  aristosa 
Helenium    autumnale 


Of  this  list,  Agrostis  alba,  Habenaria  leucophaea,  Rumex  mexi- 
canus, Oenothera  pratensis,  Steironema  ciliatum,  Verbena  hastata, 
Stachys  palustris,  Aster  salicifolius  and  Silphium  perfoliatum,  also 
sometimes  appear  on  drier  prairie,  but  they  seem  to  prefer  low 
grounds. 

Where  the  prairie  merges  into  these  lower  areas  there  is  usually  a 
mixture  of  the  two  floras  consisting  of  the  above-noted  less  hydro- 
phytic  forms  of  the  low  grounds  and  the  less  xerophytic  species 
of  the  prairie.  The  latter  includes  species  which  are  commonly 
found  on  the  richer,  less-exposed  parts  of  the  prairie,  but  also  occur 
not  infrequently  in  wet  places.  In  this  region  the  following  species, 
listed  in  the  table  of  prairie  plants,  are  of  this  type : 


Carex  gravida 
Hypoxis  hirsuta 
Thalictrum  dasycarpum 
Anemone  canadensis 
Spiraea  salicifolia 
Polygala  sanguinea 
Gentiana  Andrewsii 
Apocynum    cannabinum 

hypericifolium 
Gerardia  auriculata 


Gerardia   purpurea 
Lobelia  spicata 
Liatris  pycnostachya 
Aster  novae-anglise 
Aster  paniculatus 
Ambrosia  trifida 
Rudbeckia  subtomentosa 
Helianthus  grosseserratus 
Helianthus  tuberosus 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  following  species  in  the  prairie  table  are  restricted  in  the 
native  prairie  transect  to  the  sandy  areas  on  the  outliers  of  old 
dunes : 

Eragrostis   pectinacea    spectabilis  Ambrosia  psilostachya 

Cyperus  filiculmis  Helianthus  occidentalis 

To  them  should  be  added  Lechea  stricta,  Viola  pedata,  Asclepias 
amplexicaulis  and  Lithospermnm  Gmclini,  which  occur  in  similar 
situations  but  are  less  common. 

The  table  of  prairie  plants  contains  16  species  which  are  not  rep- 
resented in  the  prairie  transect.  All  of  these  species  occur  on  the 
prairie  of  the  general  region,  but  they  were  not  found  within  the 
limits  of  the  transect.  It  will  be  observed  that  one-half  of  them  are 
prairie  "weeds"  (see  2,  Restored  Prairie),  and  also  include  Phleum 
pratense,  an  introduced  species  which  occurs  sparingly  on  undis- 
turbed prairie. 

The  entire  native  prairie  transect  presents  a  very  characteristic 
prairie  flora,  comparable  in  its  composition  and  variations  to  that 
of  any  larger  prairie  area  in  this  part  of  the  state. 

2.     Restored  Prairie 

The  restored  prairie  appears  upon  two  types  of  surfaces, — the 
larger  fills  and  the  sides  of  the  cuts.  (For  location  of  these  see 
map,  Plate  I). 

The  prairie  flora  has  extended  quite  generally  over  the  sides  of 
the  larger  fills,  but  the  proximity  of  the  road-bed  with  its  num- 
erous weeds,  and  the  more  frequent  local  disturbances  of  the  sur- 
face caused  by  section  hands  working  along  the  road-bed,  have  re- 
sulted in  a  frequent  admixture  of  foreign  invaders. 

A  much  purer  prairie  flora  has  taken  possession  of  the  slopes  of 
the  deeper  cuts.  When  the  road  was  constructed  these  surfaces 
were,  of  course,  bare.  No  record  of  the  invasion  and  succession  of 
floras  in  these  areas  has  been  preserved,  but,  judging  from  the  his- 
tory of  more  recent  exposures  of  the  same  kind,  as  noted  by  the 
writer  in  many  cases,  the  first  plants  to  enter  were  undoubtedly 
those  enumerated  herein  as  prairie  weeds  with  some  admixture  of 
imported  weeds.  Because  of  the  newness  of  the  territory  the  lat- 
ter were  probably  not  very  numerous.  This  flora  was  gradually 
replaced  until  today  it  is  indistinguishable  from  that  of  the  ad- 
joining native  prairie. 

Several  of  these  cuts  are  found  along  the  railway  between  Wilton 
and  Summit,  and  they  are  noted  in  Plate  I. 


PERSISTENCE  OF  THE  PRAIRIE  9 

Those  within  the  first  mile  are  located  chiefly  in  the  southern 
half,  and  do  not  exceed  5  feet  in  depth. 

The  second  mile  contains  two  cuts.  Cut  a  begins  about  200  yards 
south  of  the  north  end  of  the  mile  and  extends  southward  for  about 
one-half  mile.  It  reaches  a  maximum  depth  of  11  feet,  and  its  slopes 
present  a  fine  example  of  restored  prairie.  This  also  extends  over 
the  ridges  which  were  heaped  up  above  the  sides  of  a  portion  of  the 
cut  at  the  time  the  excavation  was  made.  A  portion  of  this  cut  is 
shown  in  Plate  II,  fig.  2. 

Another  cut,  b,  is  located  near  the  south  end  of  the  mile.  This  is 
about  100  yards  long  and  reaches  a  depth  of  8  feet.  The  ridge 
here  cut  is  quite  sandy  and  the  flora  of  both  the  original  prairie 
transect  and  the  restored  slopes  show  a  scattering  of  the  species 
listed  as  characteristic  of  sandy  prairie  among  the  ordinary  species 
of  the  drier  prairie. 

The  third  mile  is  almost  flat  and  shows  but  one  small  cut  about 
3  feet  in  depth. 

The  fourth  mile  contains  another  fine  cut,  c,  which  is  more  than 
450  yards  long  and  reaches  a  depth  of  14  feet.  Ridges  heaped  up 
above  portions  of  this  also  show  restored  prairie. 

The  fifth  mile  contains  several  cuts.  Cut  d  is  more  than  500 
yards  long  and  reaches  a  maximum  depth  of  11  feet.  Cut  c  is 
about  90  yards  long  and  5  feet  deep.  A  ridge  on  either  side  above 
the  cut,  about  5  feet  wide  and  two  feet  high,  is  now  covered 
with  a  prairie  flora.  Cut  f  is  about  180  yards  long  and  8  feet 
deep.  Its  slopes  are  almost  entirely  covered  with  Robinia  pseudo- 
acacia  which  had  been  planted  nearby  and  has  extended  to  this  and 
portions  of  other  cuts.  The  Robinia  is  distinctly  a  tree-weed  and 
does  not  establish  forest  conditions. 

The  cut  which  is  located  in  the  south  half  of  the  sixth  mile  is  not 
included  in  this  discussion.  It  is  located  at  the  edge  of  the  rough, 
timbered  area  bordering  the  Mississippi  River,  and  the  railway  be- 
gins here  to  drop  rapidly  into  the  valley  of  Mad  Creek.  Its  flora 
is  mixed. 

The  faces  of  the  cuts  a  to  e,  as  well  as  the  ridges  above  the  cuts, 
have  remained  undisturbed  for  many  years,  excepting  where  goph- 
ers or  ground-hogs  have  burrowed,  or  where  limited  areas  were 
disturbed  by  man.  They  are  now  covered  with  a  typical  prairie 
flora,  which  is  recorded  in  the  second  column  of  the  prairie  table. 
It  will  be  observed  that  112  species  are  common  to  these  areas  and 
the  native  prairie  transect. 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

So  complete  is  the  extension  of  the  prairie  flora  over  the  once 
disturbed  surfaces  that  there  is  no  way  of  determining  their  limits 
on  the  prairie  side  excepting  by  the  upper  edges  of  the  cuts  and  the 
bases  of  the  ridges  which  had  been  piled  up  on  the  prairie  border- 
ing the  cuts. 

The  39  species  which  were  found  on  the  native  prairie  (recorded 
in  the  first  column)  but  not  on  the  restored  areas,  are  rare  or  local 
on  the  prairie  of  this  region.  Several,  like  Agropyron  Smithii, 
Hordeum  jubatum,  Oxybaphus  nyctagineus,  Silene  antirrhina,  Hy- 
pericum cistifolium,  Ellisia  nyctelea  and  Phy salts  prninosa,  are 
prairie  weeds  which  occur  upon  the  disturbed  spots  within  the  re- 
stored prairie,  but  have  not  been  observed  on  the  older  portions. 
Several  others,  like  Carex  scoparia,  Lilium  philadelphiciim  andi- 
nnm,  Thalictrum  dasycarpum,  Anemone  canadensis,  Poly  gala  san- 
guinea,  Geniiana  Andrewsii,  Gerardia  auriculata,  G.  purpurea, 
Rndbeckia  subtomentosa  and  Helianthus  tuberosus,  are  ordinarily 
found  only  upon  rather  moist  prairie,  and  these  drier  restored  areas 
would  not  offer  a  congenial  habitat.  The  remaining  22  species  are 
quite  rare  even  in  the  larger  native  prairie  areas  of  this  tract,  and 
their  absence  in  the  more  restricted  restored  areas  is  not  surprising. 

The  great  bulk  of  the  flora  is  the  same  on  both  types  of  areas, 
and  there  is  practically  no  admixture  of  weeds  or  other  foreign 
plants  in  either,  excepting  where  there  have  been  local  disturbances 
of  the  surface,  as  noted. 

These  disturbed  places  in  either  area  are  promptly  occupied  by 
a  mixture  of  prairie  weeds,  imported  weeds,  and  later  the  plants 
of  the  permanent  prairie.  The  plants  here  designated  as  prairie 
weeds  play  an  important  part  in  this  succession,  as  they  are  among 
the  first  to  take  possession  of  surfaces  which  have  been  disturbed 
sufficiently  to  break  up  the  prairie  turf.  Since  the  invasion  of 
our  territory  by  a  large  number  of  foreign  weeds  the  latter  join 
with  the  prairie  weeds  in  covering  new  surfaces,  but  on  the  original 
prairie  the  prairie  weeds  evidently  formed  the  first  transitional 
flora,  later  to  be  replaced  gradually  by  the  climax  prairie  flora. 
The  prairie  weeds  also  appear  on  native  prairie,  but  they  are  usually 
the  first  to  enter  broken  areas. 

Since  the  breaking  of  the  prairies  these  prairie  weeds  have  en- 
tered the  cultivated  fields  and  most  of  them  have  become  noxious 
weeds.  They  are  also  likely  to  invade  waste  places,  especially  if 
sandy  or  rather  barren.     Thirty  such  species  were  found  on  the 


PEESISTENCE  OF  THE  PRAIRIE  11 

disturbed   portions  of   the  prairie  under   discussion.     They   are 
marked  with  the  letter  x  in  the  prairie  table. 

3.    The  Roadbed 

The  middle  strip  includes  the  roadbed  and  the  lateral  drainage 
ditches,  and  is  subject  to  frequent  disturbances  by  the  section-hands 
whose  duty  it  is  to  keep  the  roadbed  in  repair.  The  ditches  fre- 
quently contain  marsh  plants  of  the  species  already  noted,  and 
need  no  further  attention  here. 

The  roadbed  includes  the  area  between  the  rails,  and  a  strip 
on  either  side  from  3  to  5  feet  in  width.  A  portion  of  it  is  well 
shown  in  Plate  II,  fig.  2.  Its  flora  is  a  mixture  and  is  derived  from 
the  following  sources : 

From  prairie. — A  large  part  is  derived  from  the  prairie  and  is 
recorded  in  the  third  column  of  the  prairie  table.  It  includes  the 
four  introduced  species  and  the  thirty  prairie  weeds,  most  of  the 
latter  being  rather  common.  Many  of  the  remaining  prairie  species 
are  represented  only  by  scattered  individuals.  The  low  form  of 
Rhus  Toxicodendron,  elsewhere  occuring  on  the  prairie,  is  also 
found  here.  This  makes  a  total  of  130  species  of  prairie  plants 
observed  on  the  roadbed. 

From  dry  open  places,  etc. — The  following  roadbed  species  were 

evidently  introduced  from  dry  borders  of  thickets  and  open  places : 

Bromus  purgans  Aster    sagittifolius 

Rubus  villosus  Gnaphalium   polycephalum 

Hypericum    Aseyron  Erigeron   animus 
Apocynum  androssemifolium 

From  sand-oallast. — The  roadbed  is  ballasted  in  part  with  sand 
brought  from  the  Cedar  River  valley.  The  following  species  oc- 
curring on  the  roadbed  were  evidently  introduced  with  the  sand : 

Paspalum    ciliatifolium  Tephrosia  virginiana 

Cenehrus    carolinianus  Astragalus  distortus 

Aristida  gracilis  Strophostyles  helvola 

Sporobolus   cryptandrus  Strophostyles  pauciflora 

Eragrostis  pectinacea  spectabile  Oxalis  filipes 

Eragrostis  Frankii  Croton  glandulosa  septentrionalis 

Festuca  oetoflora  (Enothera  rhombipetala 

Hordeum  pusiUum  Asclepias  amplexieaulis 

Cyperus  Schweinitzii  Verbena  angustifolia 

Carex  setacea  ambigua  Plantago  aristata 

Polygonum  tenue  Plantago  Purshii 

Froeliehia  floridana  Pentstemon  hirsutus 

Mollugo  vertieillata  Antennaria  neglecta 

Draba   caroliniana  Xanthium  commune 

Polanisia  trachysperma  Helianthus  petiolaris 

Crotalaria   sagittalis 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

It  is  also  probable  that  most  or  all  of  the  plants  of  Aristida 
basiramea,  Cy  perns  filwulmis  and  Helianthus  occidentalis,  noted 
in  the  prairie  table,  were  introduced  with  the  sand  ballast  rather 
than  from  proximate  sandy  prairie. 

From  wet  pkwes. — The  following  species  of  swamp  plants  were 
represented  on  the  roadbed  chiefly  by  scattered  individuals.  They 
were  probably  derived  from  the  adjoining  ditches. 

Panieum  dichotomiflorum  Polygonum  Muhlenbergii 

Agrostis  alba  Apios  tuberosa 

Muhlenbergia  mexicana  Eotala  ramosior 

Spartina  Miehauxiana  Cornus  stolonifera 

Carex  lanuginosa  Steironema   cilia  turn 

Carex    tetanica    Meadii  Verbena   liastata 

Salix  longifolia    (juv.)  Stachys   palustris 

Eumex  brittanica  Aster   salicifolius 

Eumex   mexicanus  Silphium    perfoliatuni 

From  the  forest. — The  forest  has  contributed  several  species  to 
the  roadbed,  but  chiefly  near  the  northern  end  where  the  grove 
along  the  creek  probably  constitutes  the  chief  source.  This  grove 
is  composed  of  such  species  as  Acer  saccharinum,  A.  Negundo,  Salix 
amygdaloides  and  Betula  nigra  in  the  lower  parts,  and  Ulmus 
americana,  Celt  is  occidentalis,  Juglans  nigra,  Gleditsia  triacanthos, 
Fraxinus  pennsylvanica  lanceolata,  Gary  a  cordiformis,  Crataegus 
mollis,  Prunus  serotina,  Tilia  americana,  Populus  tremuloides, 
Quereus  velutina,  Q.  macrocarpa,  etc.,  and  contains  the  usual  ac- 
companying smaller  species  of  our  alluvial  woods  and  banks. 

The  following  forest  species  were  found  on  the  roadbed,  mostly 
in  very  small  numbers  and  not  far  from  the  grove : 

Smilax   herbacea  Geranium   maculatum 

Polygonum   scandens  Psedera    quinquefolia 

Physocarpus   opulifolius  Cornus   paniculata 

Eubus  allegheniensis  Sambucus  canadensis 

Eubus    occidentalis  Erigeron  annuus 

Prunus  virginiana  Cacalia    suaveolens 

These  species  do  not  appear  constantly,  but  form  a  fluctuating 
and  inconspicuous  element  of  the  flora.  It  will  be  noted  that  most 
of  them  produce  fleshy  fruits,  and  birds  are  probably  responsible 
for  their  appearance  on  the  roadbed.  The  remaining  species  could 
easily  be  distributed  by  wind  or  moving  trains. 

The  seedlings  of  the  following  trees  have  also  been  found  from 
time  to  time: 

Populus    deltoides  Pvrus   ioensis 

Ulmus  fulva  Eobinia    pseudoacacia 

Celtis   occidentalis  Gleditsia   triacanthos 

Quereus   macrocarpa  Acer  Negundo 

Prunus   serotina  Acer   saccharinum 

Prunus   americana  Fraxinus    pennsylvanica   lanceolata 


PERSISTENCE  OF  THE  PRAIRIE  13 

None  of  these  seedlings  occur  in  large  numbers,  and  though  they 
have  been  observed  for  a  number  of  years,  none  seem  to  become  es- 
tablished. Wind  and  birds  are  probably  responsible  for  their  re- 
currence. 

It  is  possible  that  some  of  the  seedlings  of  the  species  of  Populus, 
Ulmus,  Acer  and  Fraxinus  are  derived  from  trees  cultivated  near 
the  farm-houses.  It  is  quite  certain  that  this  is  the  source  of  the 
thickets  of  Bobinia  which  occupy  parts  of  the  disturbed  surfaces 
near  Summit,  and  seedlings  of  which  sometimes  appear  on  the 
roadbed.    This  species  is  not  a  native  of  the  region. 

Introduced  weeds. — Mingled  with  the  plants  of  the  preceding 
lists  are  numerous  species  of  weeds  which  are  not  native  to  this  part 
of  the  state,  or  have  become  so  thoroughly  established  as  weeds  that 
their  source  cannot  be  determined  definitely.  They  have  been  in- 
troduced chiefly  by  gradual  diffusion  or  by  the  railway  with  stock 
and  produce,  though  wind,  birds  and  other  agencies  may  have 
assisted.  It  is  noticeable  that  the  most  persistent  of  these  weeds 
ars  usually  most  abundant  near  the  railway  stations,  this  being 
true  of  this  area  as  well  as  of  the  state  at  large. 

The  introduced  weeds  may  be  considered  in  two  groups:  those 
which  are  native  to  our  country,  and  those  which  are  of  foreign 
origin. 

The  group  of  American  weeds  includes  a  number  of  species  which 
may  be  native  to  this  part  of  Iowa,  but  they  are  now  so  generally 
distributed  as  weeds  that  they  are  included  here.  With  one  pos- 
sible exception  they  cannot  be  regarded  as  members  of  the  prairie 
flora,  though  most  of  them  occasionally  appear  upon  slightly  dis- 
turbed portions  of  the  prairie.    The  list  follows: 

Panicum   capillar e  Euphorbia   maculata 

Humulus  lupulus  Verbena  bracteosa 

Polygonum  erectum  Tencrium   canadense 

Polygonum   pennsylvanicum  Bolanum   carolinense 

Amaranthus  blitoides  Solanum   nigrum 

Lepidium  virginicum  Solanum    rostra  turn 

Sisymbrium  canescens  Physalis  subglabrata 

Oxalis  eorniculata  Veronica  peregrina 

Acalypha  virginica  Plantago    Rugelii 

Perhaps  Sisymbrium  canescens  and  Plantago  Rugelii  should  be 
included  in  the  prairie  weeds  list,  as  both  are  natives  of  the  prairies 
of  Iowa.  The  former,  however,  seems  to  be  restricted  to  waste  and 
disturbed  places  in  this  region,  and  the  latter  has  become  so  thor- 
oughly established  as  a  weed  that  it  is  often  much  more  abundant 
than  the  introduced  P.  major. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  foreign  weeds  of  the  roadbed  are  mostly  of  common  and 

widely  distributed  species,  of  which  two,  Bromus  tectorum  and 

Melilotus  alba,  are  increasing  rapidly.    The  list  follows : 

Digitaria    sanguinalis  Sisymbrium    officinale 

Echinochloa  erus-galli  Sisymbrium  altissimum 

Setaria   viridis  Sedum  purpureum   (rare) 

Setaria   glauca  Trifolium  procumbens 

Bromus  tectorum  Melilotus  alba 

Lolium  italieum  Melilotus   officinalis 

Cannabis  sativa  Pastinaca   sativa 

Eumex  crispus  Nepeta   cataria 

Eumex  acetosella  Verbascum  thapsus 

Polygonum  aviculare  Anthemis  cotula 

Polygonum  convolvulus  Arctium  minus 

Chenopodium  album  Taraxacum  erythrospermum 

Amaranthus  retroflexus  Taraxacum  officinale 

Capsella    bursa-pastoris  Lactuca   scariola 

Brassica  arvensis  Lactuca  scariola  integrata 

To  this  list  may  be  added  the  following  small  group  of  species 
which  have  escaped  from  cultivation  and  some  of  which  have  be- 
come weeds,  particularly  those  in  the  second  column : 

Triticum  sativum  Trifolium    pratense 

Zea  mays  Trifolium  hybridum 

Raphanus  sativus  Medicago   sativa 

This  interesting  mixture  of  prairie,  swamp,  forest,  and  intro- 
duced plants  represents  a  condition  which  is  common  where  new 
surfaces  have  been  created,  and  where  competition  is  possible  be- 
tween the  floras  of  the  several  types.  The  bars  and  borders  of 
most  of  our  streams  present  essentially  the  same  combination  of 
floras,  though  the  percentage  of  each  will  vary  with  the  character 
of  the  contiguous  territory  from  which  they  are  derived. 

The  struggle  between  these  floras  continues  until  that  one  which 
is  best  adapted  to  the  region  becomes  dominant.  In  the  Wilton- 
Summit  region  the  prairie  flora  would  undoubtedly  dominate  on 
the  roadbed  if  left  undisturbed,  as  it  has  done  on  the  restored 
prairie  surfaces;  along  the  streams  the  forest  would  more  fre- 
quently become  dominant;  but  in  either  case  the  earlier  mixed 
character  of  the  flora  represents  a  transition  stage  which  soon  yields 
to  the  flora  best  fitted  to  survive. 

The  presence  of  this  belt  of  mixed  floras  on  the  roadbed  is  espe- 
cially worthy  of  note  because  it  shows  that  despite  exposure  to  pos- 
sible encroachment  by  the  several  floral  elements  here  combined, 
the  prairie  flora  has  been  able  to  re-establish  itself  on  the  adjacent 
strips  of  restored  prairie  and  is  holding  its  own  against  this  varied 
competition. 


PERSISTENCE  OP  THE  PRAIRIE  15 

An  additional  interest  attaches  to  the  list  of  native  prairie  plants 
in  column  I  because  it  is  the  first  definite  published  list  of  prairie 
plants  from  the  Illinoian  drift  of  Iowa.  Previous  lists,  published 
by  the  writer3  covered  portions  of  the  prairies  on  Kansan,  Iowan 
and  Wisconsin  drifts. 

It  is  sufficient  here  to  note  that  the  prairie  flora  of  these  several 
drift  areas,  as  of  other  surface  areas  in  the  state  whether  loess  or 
alluvium,  shows  no  differentiation  which  would  indicate  or  sug- 
gest that  surface  formation  has  anything  to  do  with  the  distribution 
of  the  prairies.  On  the  contrary,  true  prairie,  with  its  characteris- 
tic flora,  occurs  on  every  type  of  soil  or  formation  which  comes  to 
the  surface  in  Iowa, .  excepting  the  muck  of  swamps,  and  even  that 
will  usually  produce  prairie  if  thoroughly  drained  and  left  un- 
disturbed. 

II.     THE  MASON  CITY  TRACT 

Another  area  illustrating  the  ability  of  the  prairie  to  return  has 
been  studied  by  the  writer  near  Mason  City  for  a  number  of  years. 
This  case  is  even  more  remarkable  than  that  discussed  in  the  first 
part  of  this  article  because  of  the  possibility  of  sharper  competition 
between  forest  and  prairie. 

This  area  is  located  between  the  north  line  of  Highlands  Addi- 
tion to  the  city  and  Buffalo  Slough,  a  swampy  abandoned  channel 
of  Lime  Creek.  The  Slough  is  bordered  by  limestone  ledges  which 
rise  to  a  height  of  35  or  40  feet,  and  have  a  prominent  rocky  forested 
talus  at  the  base.  The  forest  also  enters  the  gulleys  and  ravines 
which  cut  the  line  of  ledges.     (See  Plate  IV,  fig.  1). 

The  upland  above  the  edges  of  the  ledges  rises  to  a  height  of  50 
feet,  or  more,  above  the  bed  of  the  Slough.  It  was  formerly  cov- 
ered partly  with  native  prairie,  and  partly  with  scattered  or  in- 
terrupted groves  which  connected  more  or  less  with  the  groves  and 
thickets  of  the  talus  and  ravines.  The  area  here  considered  lies  on 
this  upland  west  of  the  line  extending  north  from  the  north  end  of 
Kentucky  Avenue  to  the  Slough.  Along  this  line  a  strip  of  native 
prairie  about  40  feet  wide  and  nearly  500  feet  long  was  broken  and 
planted  in  corn.  Along  the  west  side  of  this  strip  lies  a  piece 
of  unbroken  prairie,  while  just  east  of  it  is  a  small  upland  grove 
which  is  a  part  of  the  bluffs  forest  belt. 

The  cultivation  of  this  strip  was  soon  abandoned,  and  for  about 


'Report  on  Harrison  and  Monona  Counties,  Iowa  Geological  Survey,  vol.  XX, 
1910;  The  Prairies,  this  Bulletin,  vol.  VI,  No.  2,  1911;  The  Plant  Geography 
of  the  Lake  Okoboji  Region,  this  Bulletin,  vol.  VII,  No.  2,  1915. 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

5  years  the  writer  gave  it  only  passing  notice,  since  it  appeared 
merely  as  a  neglected  weed  patch.  Unfortunately  no  record  of  the 
plants  was  kept  during  this  period,  but  at  its  close  more  systematic 
observations  were  begun  and  continued  for  5  years.  At  the  begin- 
ning of  this  second  5  year  period  the  ridges  marking  the  old  corn- 
rows  were  still  plainly  visible,  but  the  tract  was  covered  late  in  the 
summer  with  a  mass  of  Aster  multiflorus,  A.  azureus  and  Solidago 
rigida,  with  a  scattering  of  prairie  weeds  such  as  Agropyron 
Smithii,  Hordeum  jubatum,  Potentilla  monspcliensis,  Rosa  pra- 
tincola,  Hedeoma  liispida,  Erigeron  ramosus,  Ambrosia  artemisii- 
folia  and  Achillea  millefolium;  and  of  introduced  weeds  such  as 
Phleum  pratense,  Poa  compressa,  P.  pratensis,  Tri  folium  pratense, 
T.  procumbens,  Melilotus  alba  and  Taraxacum  crythrospermum. 
The  general  appearance  of  this  strip  was  quite  different  from  that 
of  the  adjoining  undisturbed  prairie  along  the  west  side.  While 
the  two  species  of  Aster  and  the  Solidago  dominated  the  restored 
strip,  their  flowers  producing  a  distinct  belt  of  color,  the  native 
prairie  presented  a  much  larger  number  of  species,  with  none  so 
prominent  as  the  three  noted  in  the  restored  strip,  and  these  three, 
while  present,  were  scattered  and  comparatively  few  in  number. 

These  observations  have  been  continued  for  5  years,  and  in  1924 
the  number  of  prairie  species  had  been  increased,  the  species  were 
more  equally  mixed,  the  introduced  weeds  had  almost  disappeared, 
and  the  striking  distinction  between  the  restored  and  native  prairie 
had  disappeared.  The  number  of  species  is  still  distinctly  less  in 
the  restored  strip,  but  its  flora  is  clearly  of  the  prairie  type  and 
most  of  the  species  of  the  native  prairie  will  no  doubt  return  to  it 
if  it  is  not  again  disturbed. 

A  comparative  view  of  the  floras  of  the  restored  and  contiguous 
native  prairie  may  be  obtained  by  scanning  columns  V  and  IV  of 
the  Table  of  Prairie  Plants,  and,  in  addition,  the  supplementary 
lists  which  follow. 

The  following  prairie  species  should  be  added  to  both  the  native 
and  restored  prairie  lists  given  in  the  table  : 

Agropyron  Eichardsonii  Anteinjaria    plantaginifolia 

Lathy  rus   venosus  Bravmeria  pallida 

Galium    boreale 

The  following  border  plants  (also  found  in  open  woods)  were 
also  sparingly  represented  in  both  areas : 

Bromus    purgans  Apocymun    an<lrosa?mifolium 


PERSISTENCE  OF  THE  PRAIRIE  17 

The  following  species  should  be  added  to  the  native  prairie  list 

in  column  IV: 

Vicia   americana  Tarnidia  integer rima 

Khus  Toxicodendron  Aster  oblongifolius 

The  Taenidia  often  occurs  in  borders  and  open  woods ;  the  Aster 
is  often  found  in  rocky  and  barren  places ;  and  the  Rhus  is  the  low 
form  characteristic  of  the  prairies. 

The  following  species  were  sparingly  represented  on  the  restored 

prairie,  and  should  be  added  to  the  list  in  column  V  of  the  Table : 

Draba   earoliniana  Symphoricarpos    occidentalis 

Trifolium    stoloniferum  Lactuea  ludoviciana 

All  of  these  additional  species  are  found  in  the  general  region 
on  prairie  or  in  open  places.     The  Draba  usually  prefers  sand. 

Four  introduced  species,  which  now  occur  quite  rarely,  should  be 

added  to  these  lists.     Trifolium  pratense  is  found  in  disturbed 

spots  on  both  areas,  and  the  following  species  still  persist  on  the 

restored  prairie: 

Trifolium  procumbens  Taraxacum  erythrospermum 

Melilotus  alba 

The  invasion  of  the  restored  prairie  strip  took  place  almost  en- 
tirely from  the  prairie  side.  There  are  probably  two  reasons  for 
this :  Most  of  these  prairie  species  have  their  seeds  distributed  by 
wind,  and  the  prevailing  westerly  and  northwesterly  winds  of  the 
summer  and  fall  would  bring  seed  mostly  from  the  native  prairie 
lying  to  the  west;  and  the  exposure  of  this  open  area  to  drying 
agencies  would  make  it  easier  for  the  more  xerophytic  prairie  flora 
to  become  established. 

But  for  these  circumstances  the  invasion  might  have  taken  place 
quite  as  readily  from  the  contiguous  forested  tract  on  the  east  and 
north.  The  former  lies  on  the  upland  and  the  latter  along  the 
bluffs, — both  immediately  adjacent  to  the  restored  tract. 

It  is  interesting  in  this  connection  to  note  how  entirely  different 
the  flora  of  these  timbered  tracts  is  from  that  of  the  nearby  prairie. 
The  following  24  species  were  found  in  both  the  upland  woods  and 
those  of  the  banks  and  bluffs  along  Buffalo  Slough  in  the  vicinity 
of  the  restored  prairie  tracts: 

Quercus   maerocarpa  Smilax   ecirrhata 

Quercus   ellipsoidalis  Sanguinaria    canadensis 

Pyrus  ioensis  Anemone   virginiana 

Prunus  serotina  Desmodium    grandiflorum 

Prunus    virginiana  Geranium  maculatum 

Psedera   quinquefolia  Aralia  nudicaulis 

Lonicera    sempervirens  Thaspium  aureum 

Botrychium   virginianum  Polemonium  reptans 


18 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Carex  rosea 
Uvularia  grandiflora 
Allium  tricoccum 
Smilacina   racemosa 


Hydrophyllum  virginianum 
Galium  triflorum 
Solidago  latifolia 
Prenanthes   alba 


The  following  additional  30  species  were  found  only  on  the  up- 
lands : 


Quercus  alba 
Quercus  rubra 
Celtis    occidentalis 
Ribes  gracile 
Crataegus  punctata 
Zanthoxylum  americanum 
Celastrus  scandens 
Cornus  panieulata 
Asplenium   filix-femina 
Hystrix  patula 
Carex 

Polygonatum  commutatum 
Cypripedium  pubescens 
Thalictrum   dasycarpum 
Agrimonia  gryposepala 
Geum  canadense 


Geum  strictum 
Amphicarpa  monoiea 
Desmodium  bracteosum 

longifolium 
Circaea  lutetiana 
Cryptotaenia  canadensis 
Osmorrhiza  brevistylis 
Sanicula  marilandica 
Lappula  virginiana 
Monarda  fistulosa 
Serophularia  marilandica 
Phryma  leptostachya 
Triosteum  perfoliatum 
Campanula   americana 
Eupatorium  urticaefolium 


The  following  additional  45   species  were   found   only  on  the 
wooded  bluffs  and  talus : 


Juniperus   virginiana 

Populus  tremuloides 

Juglans   cinerea 

Juglans  nigra 

Carya  cordiformis 

Ostrya  virginiana 

Ulmus  fulva 

Menispermum  canadense 

Ribes  cynosbati 

Ribes  floridum 

Amelanehier  oblongifolia 

Amelanchier   spicata 

Rubus  idaeus  aculeatissimus 

Rosa  blanda 

Prunus  pennsylvanica 

Prunus  americana 

Staphylea  trifolia 

Tilia  americana 

Cornus  alternifolia 

Fraxinus  pennsylvanica  lanceolata 

Fraxinus  nigra 

Lonieera  Sullivantii 

Lonicera  dioica 


Viburnum  pubescens 
Viburnum  Lentago 
Adiantum  pedatum 
Cystopteris   bulbifera 
Cystopteris    fragilis 
Arisaema   triphyllum 
Smilacina   stellata 
Trillium   erectum 
Smilax  herbacea 
Asarum   acuminatum 
Ranunculus  abortivus 
Ranunculus  septentrionalis 
Thalictrum  dioicum 
Aquilegia  canadensis 
Actaea  rubra 
Actaea  alba 

Fragaria  vesca  americana 
Lathyrus  ochroleucus 
Viola   sororia 
Viola   scabriiiseula 
Aralia    racemosa 
Phlox   divaricata 


It  will  be  observed  that  only  7  species  of  woody  plants  (the 
woody  plants  head  each  list)  are  common  to  the  uplands  and  the 
bluffs,  and  that  8  additional  species  are  represented  in  the  upland 
woods  while  the  bluffs  woods  present  25  more.  Of  the  8  species 
from  the  upland  woods,  one,  Quercus  alba,  is  quite  rare  in  this 
vicinity,  and  the  remaining  species  are  found  on  more  remote  por- 


PERSISTENCE  OF  THE  PRAIRIE  19 

tions  of  the  bluff  area.  It  seems  evident  that  the  bluff  area  is  the 
center  of  distribution  for  the  more  lasting  woody  plants,  and  that 
the  upland  forest  has  been  produced  by  the  gradual  and  limited 
advance  of  the  forest  flora  under  the  protection  of  the  plants  of 
the  forest  border.  This  forest  border  here,  as  elsewhere  in  the  state, 
is  a  fluctuating  line  or  belt,  which  advances  more  or  less  during 
cycles  of  favorable  seasons  and  retreats  during  the  dry  cycles. 
There  is,  however,  no  general  advance  or  retreat. 

The  southern  and  western  border  of  the  upland  woods  is  here 
formed  by  rather  low,  more  or  less  scrubby  oaks,  Q.  ellipsoidalis 
and  Q.  macrocarpa,  and  in  its  more  open  portions  it  frequently 
contains  stray  individuals  or  clumps  of  species  which  belong  to  the 
prairie  of  the  region.  The  deeper  woods,  however,  present  a  pure 
forest  flora,  which  is  also  characteristic  of  the  greater  part  of  the 
sheltered  bluffs  belt  which  forms  the  northeastern  part  of  this  for- 
est area,  and  which  is  itself  limited  by  the  swamp  of  Buffalo  Slough. 

Since  the  restored  prairie  is  in  direct  contact  with  the  forested 
area  on  the  north  and  east  sides  it  would  not  be  surprising  if  the 
latter  should  invade  it  during  some  future  cycle  of  moist  seasons, 
but  such  advance  would  be  a  mere  fluctuation  such  as  has  been 
noted.  It  is  evident  that  in  this  case,  with  seemingly  equal  oppor 
tunities  for  the  forest  and  prairie  floras,  the  latter  has  taken  pos- 
session of  the  restored  tract  to  the  exclusion  of  the  former.  When 
the  prairie  turf  is  once  established  it  will  probably  hold  its  own 
against  the  encroachments  of  the  forest  if  left  undisturbed. 

Conclusions 

1. — It  is  evident  that  prairie  areas  may  be  restored  after  having 
been  cultivated  or  otherwse  disturbed.  The  prairie  flora  does  not 
represent  a  transition  state,  but  is  a  climax  flora  in  its  own  right. 

2. — The  remnants  of  the  prairie  still  persisting  in  the  state  are 
sufficient  to  furnish  seed  for  the  restoration  of  disturbed  prairie 
areas,  and  this  can  be  accomplished  if  the  latter  are  simply  left  to 
themselves. 

3. — The  restoration  of  the  prairie  flora  will  occur  gradually,  the 
earlier  transition  stages  representing  various  mixtures  of  floras  de- 
termined by  the  character  of  the  adjacent  areas. 

4. — An  important  part  in  this  transformation  is  played  by  a  cer- 
tain group  of  native  prairie  plants,  herein  designated  as  prairie 
weeds,  which  quickly  take  possession  of  new  surfaces.    They  form 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  advance  guard  of  the  prairie  flora,  and  have  become  weeds  in 
cultivated  areas. 

5. — More  recently  certain  introduced  weeds  assist  the  prairie 
weeds  in  this  process  of  restoration. 

6. — When  the  prairie  is  finally  restored  the  prairie  weeds  may 
be  incorporated  in  the  renewed  flora,  probably  usually  in  dimin- 
ished numbers,  but  the  introduced  weeds  practically  disappear. 

7. — It  is  evident  that  restoration  of  prairie  tracts  for  incorpora- 
tion with  our  state  parks  system  here  in  Iowa  is  entirely  feasible 
and  can  be  accomplished  at  little  additional  expense. 

8. — The  views  that  prairie  will  disappear  for  all  time  if  broken, 
and  that  with  the  cessation  of  prairie  fires  the  forest  will  take  pos- 
session of  the  prairie,  are  untenable  in  the  light  of  the  behavior  of 
these  and  similar  prairie  tracts. 

TABLE  OF  PRAIRIE  PLANTS 
The  following  table  contains  a  list  of  all  the  plants  found  on  the 
native  prairie  transects  between  Wilton  and  Summit,  Iowa,  and  a 
corresponding  partial  record  of  the  same  (and  a  few  additional) 
species  for  other  areas  indicated  in  the  several  columns  by  the 
letter  x.    The  columns  are  numbered  at  the  head  as  follows : 
I.     Represents  the  native  prairie  south  of  Wilton,  as  noted. 
II.     Includes  the  corresponding  flora  of  the  restored  prairie  in 
the  same  region. 

III.  Includes  the  corresponding  species  of  the  roadbed  in  the 

same  area. 

IV.  Marks  the  corresponding  species  on  the  restored  prairie  at 

Mason  City,  Iowa. 
V.     Contains  the  corresponding  species  on  the  restored  prairie 

at  Mason  City. 
Supplementary  lists  are  given  in  the  text  in  connection  with  the 
discussion  of  each  of  the  localities. 

Plants  marked  with  an  asterisk  (*)  have  been  introduced,  but 
are  sparingly  established  on  the  prairie. 

Plants  marked  with  an  x  before  the  name  belong  to  the  group 
herein  designated  as  "prairie  weeds. " 

The  nomenclature  of  Gray's  Manual,  7th  edition,  is  employed  for 
native  or  established  plants,  and  that  of  Gray's  School  and  Field 
Botany  for  other  introduced  plants.  Hence  authors'  names  are 
omitted  throughout  the  paper. 


PERSISTENCE  OF  THE  PRAIRIE 


21 


TABLE  OF  PEAIRIE  PLANTS 


I 

II 

III 

IV 

V 

Family  Equisetaceae 

xEquisetum    arvense 

+ 

+ 

+ 

Equisetum  hyemale  intermedium 

+ 

+ 

+ 

Family  Gramineae 

Andropogon    scoparius 

+ 

+ 

+ 

'      + 

+ 

Andropogon  furcatus 

+ 

+ 

+ 

+ 

Sorghastrum  nutans 

+ 

+ 

+ 

+ 

+ 

Panicum    virgatum 

+ 

+ 

+ 

Panicum  huachuchse 

+ 

+ 

+ 

Panicum  Scribnerianum 

+ 

+ 

+ 

+ 

Stipa  spartea 

+ 

+ 

+ 

+ 

Aristida  basiramea 

+ 

+ 

Muhlenbergia  racemosa 

+ 

+ 

+ 

+ 

+ 

*Phleum  pratense 

+ 

+ 

+ 

+ 

Sporobolus   heterolepis 

+ 

+ 

+ 

Agrostis  hyemalis 

+ 

+ 

+ 

Agrostis  alba  vulgaris 

+ 

+ 

+ 

Sphenopholis  obtusata 

+ 

Koeleria  eristata 

+ 

+ 

+ 

+ 

Bouteloua  curtipendula 

+ 

+ 

+ 

*Poa  eompressa 

+ 

+ 

+ 

+ 

+ 

*Poa   pratensis 

+ 

+ 

+ 

+ 

+ 

xAgropyron    Smithii 

+ 

+ 

+ 

+ 

xHordeum  jubatum 

+ 

+ 

+ 

Elymus  canadensis 

+ 

+ 

.+ 

+ 

+ 

Family  Cyperaceae 

Cyperus   filiculmis 

+ 

+ 

+ 

Carex  seoparia 

+ 

Carex  festucacea 

+ 

+ 

+ 

+ 

Carex  gravida 

+ 

Carex   pennsylvanica 

+ 

+ 

Family  Commelinaceae 

Tradescantia  reflexa 

+ 

+ 

+ 

Family  Liliaceae 

Allium  canadense 

+ 

Lilium  philadelphicum 

+ 

+ 

Lilium   philadelphicum  andinum 

+ 

*Asparagus  officinalis 

+ 

+ 

+ 

Smilacina  stellata 

+ 

+ 

+ 

Family  Amaryllidaceae 

Hypoxis  hirsuta 

+ 

Family  Iridaceae 

Sisyrinehium  campestre 

+ 

+ 

+ 

+ 

Family  Orehidaceae 

Spiranthes  gracilis 

+ 

+ 

Family  Salicaceae 

Salix  humilis 

+ 

+ 

-  + 

+ 

+ 

Family  Betulaceae 

Corylus  americana 

+ 

+ 

+ 

+ 

Family  Santalaceae 

Comandra    umbellata 

+ 

+ 

+ 

Family  Polygonaceae 

Eumex   altissimus 

+ 

+ 

+ 

Polygonum  ramosissimum 

+ 

Family  Chenopodiaceae 

Chenopodium    leptophyllum 

+ 

22 


IOWA  STUDIES  IN  NATURAL  HISTORY 


I 

II 

III 

IV 

V 

Family  Nyctaginaceae 

xOxybaphus  nyetagineus 

+ 

1 

Family  Caryophyttaceae 

xSilene  antirrhina 

+ 

+ 

+ 

Silene  stellata 

+ 

+ 

Family  Eanunculaceae 

Ranunculus   fascieularis 

+ 

+ 

+ 

Thalictrum  dasyearpum 

+ 

+ 

Anemone   eylindriea 

+ 

+ 

4- 

+ 

+ 

Anemone  canadensis 

+ 

+ 

Family  Cruciferae 

xLepidium  apetalum 

+ 

+ 

+ 

+ 

Family  Saxifragaceae 

Heuchera  hispida 

+ 

+ 

+ 

+ 

Family  Rosaceae 

Spiraea  salicifolia 

+ 

+ 

+ 

Fragaria  virginiana 

+ 

+ 

-f" 

+ 

+ 

Potentilla  arguta 

+ 

+ 

i 

+ 

xPotentilla  monspeliensis 

+ 

+ 

+ 

Potentilla  canadensis 

+ 

+ 

+ 

Rosa  pratincola 

+ 

+ 

-f 

+ 

+ 

Family  Leguminosae 

xCassia  chamaecrista 

+ 

+ 

+ 

Baptisia  bracteata 

+ 

+ 

Baptisia  leucantha 

+ 

Amorpha   canescens 

_i_ 

+ 

+ 

I 

+ 

Petalostemum    purpureum 

t 

+ 

+ 

+ 

+ 

Petalostemum  candidum 

_L 

4- 

-i— 

+ 

+ 

Astragalus  canadensis 

+ 

+ 

4" 

Desmodium  illinoense 

+ 

+ 

+ 

Desmodium   canadense 

+ 

+ 

+ 

+ 

+ 

Lespedeza    capitata 

+ 

+ 

4- 

+ 

+ 

Amphicarpa  Pitcheri 

+ 

+ 

+ 

xTrifolium   repens 

+ 

! 

+ 

Family  Linaceae 

Linum  sulcatum 

+ 

+ 

+ 

+ 

Family  Oxalidaceae 

Oxalis    violacea 

+ 

+ 

+ 

xOxalis   stricta 

+ 

+ 

Family  Polygalaceae 

Polygala  sanguinea 

+ 

+ 

Polygala  Senega 

+ 

+ 

+ 

Polygala   vertieillata 

+ 

Family  Euphorbiaceae 

xEuphorbia  Preslii 

4~ 

Euphorbia  corollata 

+ 

+ 

+ 

Family  Anacardiaceae 

Rhus   glabra 

+ 

+ 

i 

+ 

Family  Mhamnaceae 

Ceanothus   americanus 

+ 

+ 

+ 

+ 

+ 

Family  Vitaceae 

Vitis    vulpina 

+ 

+ 

+ 

+ 

Family  Hypericaceae 

xHypericum   cistifolium 

+ 

+ 

Family  Cistaceae 

Helianthemum  ma  jus 

+ 

+ 

Helianthemum    canadense 

+ 

+ 

Family  Yiolaceae 

xViola  cucullata 

+ 

4- 
i 

PERSISTENCE  OP  THE  PRAIRIE 


23 


I 

II 

III 

IV 

V 

Viola  fimbriatula 

+ 

+ 

+ 

"Viola    pedatifida 

+ 

+ 

+ 

+ 

+ 

Family  Onagraceae 

xOEnothera  biennis 

+ 

+ 

+ 

+ 

Gaura  biennis 

+ 

+ 

+ 

Family  Umbelliferae 

Eryngium  yuccifolium 

+ 

+ 

+ 

+ 

Zizia  aurea 

+ 

+ 

+ 

Family  Primulaceae 

Dodeeatheon  Meadia 

+ 

Family  Gentianaceae 

Gentiana    puberula 

+ 

+ 

+ 

Gentiana  Andrewsii 

+ 

Gentiana  flavida 

+ 

+ 

+ 

+ 

Family  Apocynaceae 

xApocynum  cannabinum 

+ 

+ 

+ 

Apocynum  cannabinum  hypericifolium  + 

Family  Asclepiadaceae 

Asclepias  tuberosa 

+ 

+ 

+ 

+ 

+ 

xAsclepias   syriaea 

+ 

+ 

+ 

Asclepias  verticillata 

+ 

+ 

+ 

Acerat.es  floridana 

+ 

+ 

Acerates  viridiflora 

+ 

+ 

+ 

Acerates  viridiflora  lanceolata 

+ 

+ 

+ 

Family  Convolvulaceae 

xConvolvulus   sepium 

+ 

+ 

+ 

Family  Polemoniaceae 

Phlox  pilosa 

+ 

+ 

+ 

+ 

+ 

Family  Bydrophyllaeeae 

xEllisia  nyctelea 

+ 

+ 

Family  Boraginaceae 

Lithospermum  canescens 

+ 

+ 

+ 

4- 

Family  Verbenaceae 

xVerbena  stricta 

+ 

+ 

+ 

Family  Labiatae 

Scutellaria  parvula 

-f 

+ 

Monarda   mollis 

+ 

+ 

+ 

+ 

+ 

xHedeoma  hispida 

+ 

+ 

+ 

+ 

Pycnanthcmum  flexuosum 

+ 

+ 

+ 

Pycnanthemum  pilosum 

+ 

+ 

Family  Solanaceae 

xPhygalis  pruinosa 

+ 

+ 

+ 

Physalis   virginiana 

+ 

+ 

+ 

+ 

Family  Serophvlariaeeae 

Scrophularia   leporella 

+ 

+ 

+ 

Veronica  virginica 

+ 

+ 

+ 

Gerardia   auriculata 

+ 

Gerardia  aspera 

+ 

Gerardia  purpurea 

+ 

Gerardia   Skinneriana 

+ 

Pedicularis  canadensis 

+ 

+ 

+ 

Family  Acanthaceae 

Ruellia    ciliosa 

+ 

Family  Campanulaceae 

xSpecularia   perfoliata 

+ 

+ 

Family  Lobeliaceae 

Lobelia  spicata 

+ 

+ 

+ 

+ 

+ 

24 


IOWA  STUDIES  IN  NATURAL  HISTORY 


I 

ii 

III 

IV 

V 

family   Compositae 

Kuhnia    eupatoroides    eorymbuloaggP- 

+ 

_i_ 

+ 

+ 

Liatris    cylindracea 

+ 

Liatris   scariosa 

+ 

+ 

+ 

+ 

+ 

Liatris    pycnostaehya 

+ 

+ 

+ 

Solidago   speciosa   angustata 

+ 

_L 

4- 

+ 

J 

Solidago   missouriensis 

+ 

+ 

4_ 

Solidago  nemoralis 

+ 

+ 

4- 

+ 

+ 

Solidago  canadensis 

+ 

+ 

— 

+ 

+ 

xSolidago  rigida 

i 

+ 

+ 

+ 

+ 

Solidago   graminifolia 

+ 

+ 

+ 

Aster    novse-anglise 

~r 

4- 

+ 

+ 

Aster  sericeus 

+ 

+ 

+ 

Aster  azureus 

+ 

+ 

4- 

+ 

Aster   laevis 

+ 

+ 

+ 

+ 

Aster  multiflorus 

+ 

+ 

+ 

+ 

+ 

Aster   paniculatus 

+ 

4- 

+ 

xErigeron  ramosus 

+ 

+ 

i 

-r 

4_ 
i 

4- 

xErigeron  canadensis 

+ 

+ 

+ 

+ 

Antennaria   neglecta 

a. 

+ 

+ 

+ 

Silphium  laciniatum 

+ 

4- 

4- 

Silphium  integrif olium 

+ 

+ 

_L 

Parthenium  integrifolium 

+ 

+ 

+ 

x Ambrosia   trifida 

+ 

+ 

+ 

x Ambrosia   artemisiifolia 

_i_ 

1 

+ 

+ 

xAmbrosia  psilostachya 

+ 

+ 

4- 

+ 

Heliopsis    scabra 

+ 

+ 

4. 

+ 

4- 

Eudbeckia  subtomentosa 

+ 

Eudbeckia   hirta 

+ 

+ 

+ 

+ 

_i_ 

Brauneria   pallida 

+ 

+ 

+ 

Lepachys    pinnata 

+ 

+ 

+ 

+ 

_u 

Helianthus    scaberrimus 

+ 

+ 

+ 

+ 

4- 

Helianthus  occidentalis 

+ 

+ 

+ 

+ 

xHelianthus  grosseserratus 

+ 

4. 

l 

+ 

+ 

Helianthus  tuberosus 

+ 

+ 

Coreopis  palmata 

+ 

+ 

+ 

+ 

+ 

Coreopis  tripteris 

+ 

+ 

+ 

xAchillea  millefolium 

+ 

+ 

+ 

+ 

+ 

Artemisia   caudata 

+ 

+ 

+ 

+ 

Artemisia   serrata 

+ 

Artemisia  ludoviciana 

+ 

+ 

+ 

+ 

+ 

Cacalia  tuberosa 

+ 

Senecio    plattensis 

+ 

4- 

+ 

+ 

Cirsium   discolor 

+ 

+ 

-i- 

+ 

+ 

Cirsium  iowense 

+ 

Cirsium   Hillii 

+ 

+ 

+ 

Krigia   amplexicaulis 

+ 

Lactuca   canadensis 

+ 

+ 

+ 

+ 

Prenanthes  racemosa 

+ 

+ 

+ 

PLATE  I 


W.{LJON ._._,r.T__ 


3£. 


oO 


<r> 


Summit 


•£", 


rJEL 


z» a 


■I 


Wilt  on- Summit  tract 
(For  explanation  see  next  page) 


EXPLANATION  OF  PLAT  OF  WILTON-SUMMIT  TRACT 

Each   of  the  three  sections  represents  2   miles. 

Miles  are  numbered  from  north  to  south  with  Roman  numerals. 

The  horizontal  dotted  lines  mark  quarter  miles. 

The  section  lines  are  marked  with  heavy  broken  lines. 

The  railway   runs   on  section  lines  to   near   Summit. 

Its  right  of  way  and  the  intersecting  roads  are  marked  with  full  lines.     Both 

are  exaggerated  in  width. 
The  cross-lines  mark  the  fills,  the  largest  about  9  feet  high. 
The  dotted  areas  are  low  and  wet. 

The  black  areas  represent  cuts.     They  are  distributed  as  follows: 
Mile  I. — Three  cuts  3  to  5  feet  deep. 
Mile  II. — Cut  a  is  about  one-half  mile  long  and  reaches  11  feet  in  depth. 

Cut  b  is  about  100  yards  long  and  8  feet  deep. 
Mile  III.— One  cut  3  feet  deep. 

Mile  IV. — Cut  c,  more  than  450  yards  long  and  reaching  14  feet  in  depth. 
Mile  V. — Cut  d,  nearly   500   yards  long  and   14  feet   deep. 
Cut  e,  less  than  200  yards  long  and  5  feet  deep. 
Cut  i,  about  180  yards  long  and  8  feet  deep. 
Mile  VI. — The  large  cut  .is  just  outside  of  our  area. 


PLATE   II 


Fig.  1.     Illinoian  drift  prairie  south  of  Wilton. 


Fig.  2.     Cut  a,  looking  south.     Shows  restored  prairie.     South  of  Wilton. 


PLATE  III 


Fig.  1.     Native  prairie  along  railway.     Looking  north  from  cut  b. 
Partlv  low.      South   of  Wilton. 


■'-1 


*■■-*  --a 


ti  *■  w*>>  v  -  ■  ■•   > ,  I  * ..  - . "   -v.  *  -  - .'-  v-Nifii  -  -Si 


ftMJt  S  ~**  M  «H**, If 


$:.*,i 


S«£ 


,-*Vs 


Fig.  2.     Native  prairie  at  cut  a.     Looking  south. 


PLATE   IV 


«» 

®* 

.'■* 

*& 

>'n 

r--- 

^ . 

**• 

. 

"T^^i. 

«*-^   '-  4JL  s 

I%; 

^^&fcfci^fe^^^  'U,^.%i*'x^'%i*^4^L%^& 

WlM 

^^V'^te 

Epif*.. 

Rfc 

"**^-        •                         -  '^^^^^SW 

H  o»|''w^        f^siMM 

-  ''^'~'  "  '                        ^^^^^^^^ 

'wKiira^  '^l^^K 

$r   ;  = 'JKOM 

wF^lt 

& 

W*3$$t?' 

Fig.    1.     Looking  nearly    south    across   Buffalo    Slough   towards   the 
wooded   bluffs  just  east  of  restored  prairie.     Mason  City. 


Fig.   2.     A  bit   of  native  prairie  with  forest  'border.      Near  restored 
prairie  at  Mason  City. 


THE  PRAIRIE  FLORA  OF  MANITOBA 

B.  Shimek 

The  prairies  originally  occupied  a  large  part  of  the  Mississippi 
Valley  and  the  region  to  the  north.  They  extended  southward  to 
Oklahoma  and  Texas ;  eastward  through  Illinois,  Indiana  and  Ohio, 
including  also  the  barrens  of  Kentucky  and  Tennessee ;  and  west- 
ward and  northwestward,  including  seven-eighths  of  the  area  of 
Iowa,  the  southern  and  western  parts  of  Minnesota,  eastern  Kan- 
sas, Nebraska  and  the  Dakotas,  and  thence  into  the  southern  por- 
tions of  the  provinces  of  Canada  east  of  the  Rocky  Mountains. 

They  extended  over  almost  every  type  of  topography  and  soil 
found  within  that  area,  and  there  is  nothing  in  either  which  defi- 
nitely marks  or  determines  the  character  of  the  prairie.  There  is 
substantial  agreement  in  but  one  character, — the  flora.  The 
prairies  are  treeless,  or  practically  so,  and  the  greater  part  of  the 
flora  consists  of  perennial  herbs  of  a  distinctly  xerophytic  type, 
the  Gramineas  being  most  numerous  in  individuals  though  exceed- 
ed by  the  Composite  in  number  of  species,  with  the  Leguminosae 
following  as  third  in  order. 

The  prairies  were  continuous  over  large  areas,  or  were  inter- 
rupted by  groves,  swamps  and  sand-dune  areas,  or  were  limited  to 
small  areas  hemmed  in  by  forest  or  swamp.  Whatever  their  extent, 
however,  they  agreed  in  the  character  of  their  original  flora,  now 
reduced  over  most  of  the  area  to  mere  remnants.  The  typical 
prairie  flora,  as  represented  in  Iowa,  extended  over  the  entire  area, 
but  at  its  western  margins  it  blended  more  or  less  with  the  still 
more  xerophytic  flora  of  the  great  plains. 

The  present  paper  presents  a  brief  discussion  of  this  flora  as  it 
appears  in  a  portion  of  southern  Manitoba,  still  well  within  the 
prairie  area,  but  near  its  northern  border.  The  vicinity  of  Car- 
berry,  about  100  miles  west  of  Winnipeg,  was  chosen  for  study  be- 
cause an  earlier  list  of  the  flora  of  the  region  had  been  published 
by  Christy.1  This  list  was  prepared  on  the  basis  of  observations 
made  in  1883  and  1884,  when  the  region  was  just  being  settled  and 


*Christy,  E.  Miller,  Notes  on  the  Botany  of  Manitoba.    Journal  of  Botany,, 
vol.  XXV,  1887. 

25 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

presented  much  of  the  prairie  in  its  primitive  condition.  In  1920 
the  writer  found  the  prairie  of  the  region  mostly  under  cultivation, 
but  few  tracts  remaining  unbroken.  The  best  illustrations  of  the 
prairie  flora  were  preserved  in  the  unbroken  strips  along  the  rail- 
way right  of  way,  and  on  limited  tracts  west  and  northwest  of  Car- 
berry.    For  an  illustration  of  the  latter  see  Plate  VI,  fig.  1. 

The  Canadian  Pacific  Railway  was  constructed  when  the  region 
was  still  practically  unsettled,  and  its  right  of  way  has  preserved  a 
transect  of  the  native  prairie  along  both  sides  of  the  roadbed  for 
about  three  miles  on  either  side  of  Carberry.  A  portion  of  it  is  il- 
lustrated in  Plate  VI,  fig.  2.  The  Canadian  Northern  Railway  has 
little  prairie  on  its  right  of  way  north  and  south  of  the  station  as 
it  was  built  after  most  of  the  surface  was  broken.  Some  attention 
was  also  given  to  the  strips  of  prairie  along  the  Canadian  Pacific 
right  of  way  both  east  and  west  of  MacGregor, — about  thirty  miles 
east  of  Carberry. 

Carberry  lies  in  a  lobe  of  the  prairie  plain  which  is  bounded  by 
the  northern  margin  of  the  great  sand-dune  area  which  extends 
along  the  Assiniboine  River  for  about  150  miles.  The  location  of 
the  lobe  is  shown  in  the  map,  Plate  V.  Its  surface  is  quite  level, 
being  somewhat  broken  only  by  a  few  very  shallow  kettleholes  (now 
mostly  dry),  and  near  the  margins  by  low  outliers  of  the  dune  area. 
Its  marginal  portions  and  irregular  areas  scattered  over  its  sur- 
face are  quite  sandy,  but  most  of  it  is  fertile  and  was  originally 
covered  with  a  prairie  flora,  w^hich  was  interrupted  only  by  the 
kettleholes.  The  latter  were  bordered  by  a  marsh  flora,  of  which 
little  remains,  in  some  cases,  and  by  thickets  consisting  largely  of 
Popuhts  tremuloides,  some  of  which  still  persist. 

The  sand-dune  area,  which  extends  for  many  miles  along  the 
southern  border  of  the  prairie  of  which  the  Carberry  lobe  is  a 
part,  was  studied  only  in  the  region  including  the  lobe.  Much  of 
its  border  is  quite  abrupt,  but  occasionally  it  shades  off  gradu- 
ally into  sandy  prairie,  as  at  Brandon  Junction.  Its  surface  pre- 
sents a  variety  of  features.  Much  of  it  is  of  the  usual  dune  type 
(see  Plate  VIII,  fig.  2),  but  there  are  large  gently  sloping  or  flat 
areas,  which,  though  very  sandy,  are  largely  covered  with  a  prairie 
flora.    Such  areas  are  shown  in  Plate  VII,  fig.  2,  and  Plate  VIII, 

fig.  1. 

One  of  the  finest  areas  of  this  type  is  known  as  Spruce  Plain. 
It  is  located  southwest  of  Carberry,  and  a  little  of  the  eastern  mar- 


PRAIRIE  FLORA  OF  MANITOBA  27 

gin  is  shown  on  the  map,  Plate  V.  It  lies  in  the  heart  of  the  dune 
area,  but  its  surface  is  flat,  or  but  gently  rolling.  A  portion  of  it 
is  shown  in  Plate  VII,  fig.  2.  While  a  large  part  of  it  is  treeless, 
thickets  and  clumps  of  white  spruce,  Picea  canadensis,  are  scat- 
tered over  its  surface,  giving  it  its  name.  The  treeless  surfaces  are 
covered  with  an  almost  pure  prairie  flora. 

The  rougher  portions  of  the  dune  area  are  more  or  less  covered 
with  thickets,  particularly  in  the  depressions  and  around  the  ponds 
or  bogs  which  occupy  them.  The  largest  of  these  swamps  lies  a 
little  to  the  west  of  the  area  mapped,  and  is  an  extensive  tamarack 
muskeg  which  surrounds  a  small  lake. 

The  dune  area  crosses  the  Canadian  Pacific  about  four  miles  west 
of  Carberry,  and  a  narrow  lobe  extends  northward  about  three 
miles  to  the  east,  as  shown  on  the  map.  Another  lobe  crosses  the 
line  of  the  railway  near  Sidney,  east  of  the  area  mapped;  but 
beyond  that,  eastward,  the  border  of  the  sandhills  sweeps  well  to 
the  south. 

The  MacGregor  area  is  typical,  nearly  level  fertile  prairie,  and 
practically  all  excepting  the  right  of  way  is  under  cultivation.  The 
latter  shows  good  transects  of  native  prairie,  varied  occasionally 
by  slight  depressions  which  contain  a  marsh  flora.  Some  of  the 
depressions  in  this  region  are  also  bordered  by  thickets. 

THE  FLORA 

No  detailed  study  of  the  flora  of  the  swamp  areas  and  thickets 
was  attempted,  but  incidental  observations  were  made  in  connec- 
tion with  the  closer  study  of  the  xerophytic  flora  of  the  prairies 
and  the  dunes.  Some  notes  on  these  observations  will  be  of  in- 
terest because  they  reveal  the  floral  types  which  occupy  modified 
portions  of  these  xerophytic  areas. 

The  Swamp  Flora. — The  finest  display  of  this  flora  was  pre- 
sented by  the  great  muskeg  in  the  Spruce  Plain  region.    The  follow- 
ing list  of  plants  will  suggest  the  general  floral  character  of  the 
area,  the  tamarack  being  dominant  over  its  greater  part: 
Larix  laricina  Salix  Candida 

Equisetum   fluviatile  Salix   petiolaris 

Triglochin   maritima  Sarracenia    purpurea 

Calamagrostis   canadensis  Parnassia   palustris 

Eriophorum  angustifolium  majus  Menyanthes  trifoliata 

Carex   hystricina  Galium  Claytoni 

Tofieldia  glutinosa  Lobelia  Kalmii 

Smilacina  trifolia  Aster    junceus 

Habenaria   hyperborea 


28 


IOWA  STUDIES  IN  NATURAL  HISTORY 


In  the  smaller  more  or  less  marshy  tracts  on  the  prairie  and  dune 
areas  the  following  additional  species  were  observed: 


Equisetum  hyemale  robustum 

Typha  latifolia 

Alisma  plantago-aquatiea 

Phalaris   arundinacea 

*Agrostis  alba 

Calamovilfa  longifolia 

Spartina  Michauxiana 

Spartina  gracilis 

Phragmites  communis 

Eragrostis   Frankii 

Poa  triflora 

Elymus  virginicus 

Seirpus   validus 

Eriophorum  angustifolium  ma  jus 

Carex  filif ormis 

Carex  Sartwellii 

Carex  Bebbii 

Spirodela  polyrhiza 

Juneus  bufonius 

Juncus  balticus  littoralis 

Lilium  canadense 

Cypripedium  parviflorum 

Salix   longifolia 

Salix  discolor 

*  Salix  rostra ta 

Betula   pumila   glandulifera 

Urtica  gracilis 

Eumex  mexicanus 

*Anemone  canadensis 


Caltha   palustris 

Ribes  floridum 

*  Spiraea    salicifolia 

Potentilla  fruticosa 

Rubus    triflorus 

Lathyrus  palustris 

Lathyrus   palustris   myrtifolius 

*Epilobium  angustifolium 

Hippuris   vulgaris 

Cicuta  maeulata 

Sium  cicutaefolium 

Cornus   stolonifera 

Steironema   ciliatum 

Apocynum    cannabinum 

hypericifolium 
Gentiana    Andrewsii 
Asclepias    incarnata 
*Stachys  palustris 
Mentha  arvensis  canadensis 
Castilleja  pallida  septentrionalis 
Pedicularis  lanceolata 
Plantago  eriopoda 
Campanula  aparinoides 
Aster  umbellatus 
Erigeron  philadephicus 
Artemisia  biennis 
Petasites  sagittatus 
Cirsium  muticum 


Several  of  the  species  in  this  list  also  appear  in  the  prairie  list. 
They  are  marked  with  an  asterisk.  These  species  usually  grow  in 
moist  places,  but  sometimes  they  extend  to  drier  prairies.  Bibes 
floridum  also  appears  in  moist  woods. 

The  Forest  Flora. — Two  groups  of  forest  plants  are  more  or  less 
distinguishable  in  this  region, — those  of  the  more  xerophytic  dunes, 
and  those  of  the  sheltered  ravines  and  borders  of  swamps  or  ponds. 

The  following  list  includes  the  species  observed  on  the  dry  dunes, 

— often  in  thickets: 

Amelanchier  spicata 
Crataegus,  sp. 
Agrimonia    striata 
Prunus  virginiana 
Prunus  pennsylvanica 
*Rhus  Toxicodendron 
*Elaeagnus   argentea 
Monarda  fistulosa 
Lonicera  glaucescens 

The  species  marked  with  an  asterisk  are  also  found  in  the  prairie 

list. 


Picea  canadensis 

Bromus  ciliatus 

*Bromus  purgans 

Smilax  herbacea  pulverulenta 

Populus  tremuloides 

*Quereus  macrocarpa 

Thalietrum  dioicum 

Actaea  rubra 

Arabis  canadensis 


PRAIRIE  FLORA  OP  MANITOBA  29 

The  following  species  are  usually  found  near  the  borders  of 

thickets,  and  may  extend  out  on  the  prairie : 

Bromus  ciliatus  Prunus  virginianus 

Smilax  herbacea  pulverulenta  Rubus  idseus 

*Corylus  americana  Rubus  occidentalis 

Polygonum  scandens  Sanicula  marilandica 
Erysimum  cheiranthoides 

The  Corylus  is  also  frequent  on  the  prairie,  and  the  species  of 
Prunus  and  Eubus  have  probably  been  carried  out  upon  the  prairie 
by  birds,  as  they  are  usually  found  along  fences  or  telegraph  wires, 
which  serve  as  perches  for  birds. 

The  following  species  were  found  in  the  more  moist  and  better 
sheltered  thicket : 

Equisetum  pratense  Thaspium  aureum 

Equisetum  sylvaticum  Cornus  canadensis 

Agrostis  perennans  Pyrola  elliptica 

Populus  balsamifera  Pyrola  americana 

Populus   acuminata  *Steironema  cilia  turn 

Betula  alba  Castilleja  miniata 

Alnus  incana  Viburnum  opulus  americanum 

Anemone  virginiana  Eupatorium  purpureum 

Actaea  alba  Solidago  ulmif  olia 

Ribes  floridum  *Solidago  serotina 

Rubus   triflorus  Rudbeckia  laciniata 

Rosa  blanda  Cacalia  suaveolens 

Acer  Negundo  Lactuea  spicata 

*Epilobium  angustifolium  Prenanthes  alba 

Aralia  nudicaulis 

The  species  marked  with  an  asterisk  also  appear  upon  richer 
prairie. 

A  few  prairie  plants  may  also  be  found  in  the  more  open  por- 
tions of  the  groves.    The  following  were  noted : 

Equisetum  hyemale  intermedium  Convolvulus  sepium 

Elymus  canadensis  Agastaehe  Fceniculum 

Thalictrum   dasycarpum  Galium  boreale 

Heuchera  hispida  Symphoricarpos    occidentalis 

Fragaria   virginiana  Rudbeckia   hirta 

The  Dune  Flora. — The  Manitoba  prairie  list  shows  96  species  of 

prairie  plants  which  are  also  found  upon  the  dunes  bordering  the 

Carberry  prairie  lobe.     They  were  collected  east,  west  and  south 

of  Carberry.     In  addition  to  these  prairie  species  the  dunes  and 

sandy  areas  yielded  the  following  distinctively  sand  species: 

Selaginella   rupestris  Androsace   occidentalis 

Juniperus  horizontals  Opuntia   polyacantha 

Cyperus   Schweinitzii  Arctostaphylos  Uva-ursi 
Chamaerhodos  erecta 

Oeum  triflorum  and  Asclepias  tuberosa  were  also  found  here  only 

on  the  dunes,  but  both  occur  on  ordinary  prairie  elsewhere.    Arabis 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

Drummondiij  which  is  given  in  the  prairie  list,  was  also  found  here 
only  upon  sandy  areas.  It  is  scarcely  a  characteristic  prairie  plant, 
but  occurs  on  dry  areas  of  various  types.  Panicnm  Scribnerianum 
is  likewise  found  on  ordinary  prairie  elsewhere. 

The  Prairie  Flora. — The  prairie  flora  may  be  considered  in  two 
rather  illy-defined  groups.  The  one  includes  the  plants  of  the 
sandy  prairie  collected  within  the  Carberry  lobe,  and  the  other  the 
flora  of  the  more  fertile  prairie. 

The  former  is  listed  in  column  II,  of  the  Manitoba  prairie  list, 
and  its  125  species  differ  from  those  of  the  richer  prairie  only  in 
that  the  less  xerophytic  forms  are  wanting,  and  that  two  species 
of  sand  plants  are  included,  namely  Androsace  Occident  alls  and 
Arctostaphylos  Uva-iirsi.  Pohjgala  Senega  and  Acerates  viridi- 
flora  were  collected  only  upon  the  sandy  prairie,  but  they  occur  on 
ordinary  prairie  almost  everywhere. 

The  flora  of  the  more  fertile  prairie  in  the  vicinity  of  Carberry 
is  listed  in  column  I,  and  that  from  the  prairie  at  MacGregor  in 
column  IV.  It  will  be  observed  that  the  more  fertile  prairie  of 
MacGregor  yielded  several  species,  belonging  to  the  genera  Sorg- 
hastrum,  Panicum,  Sporobolus,  Sisyrinchiiim,  Amorpha,  Asclepias, 
Helianthus  and  Prenanthes,  which  are  characteristic  of  the  richer 
prairies  in  Iowa,  and  elsewhere,  but  which  are  lacking  on  the  Car- 
berry prairie.  The  latter,  however,  yielded  130  species,  as  against 
110  from  MacGregor.  The  additional  species  from  Carberry  are 
mostly  more  xerophytic  types.  The  locality  was  more  thoroughly 
worked  than  that  at  MacGregor,  and  that  may  account  in  part  for 
the  difference. 

The  15  species  marked  with  an  asterisk  in  the  Manitoba  prairie 
list,  are  not  known  on  the  prairies  of  Iowa.  Several  are  far  western 
and  northwestern  species,  and  a  few  like  the  species  of  Lychnis  and 
Erysimum,  are  scarcely  characteristic  prairie  plants,  but  may  occur 
in  almost  any  dry  situation.  The  great  bulk  of  this  prairie  flora 
is  identical  with  that  of  Iowa. 

Column  V  contains  the  species  reported  by  Christy, — in  some 
cases  under  other  names  than  those  here  employed.  He  does  not 
report  Anemone  cylindrica,  but  evidently  included  it  with  A.  vir- 
giniana,  both  being  very  common.  Two  evident  errors  occur  in  the 
report  of  Quercus  alba  and  Jiiniperus  virginiana  from  the  sand- 
hills. The  former  is  undoubtedly  Q.  macrocarpa,  which  is  very 
common,  and  the  latter  is  Juniperus  horizontalis. 


PKAIRIE  FLORA  OF  MANITOBA  31 

Several  of  the  species  in  his  list  were  not  found  by  the  writer, 

but  among  them  only  the  following  are  prairie  or  sand  species : 

Helianthemum  canadense  Astragalus   monticola 

Geranium  carolinianum  Aster    vimineus 

Astragalus   caryocarpus  Castilleja  coccinea 

Christy's  explanation  of  the  cause  of  the  treelessness  of  the 
prairies  (fire)  will  be  discussed  by  the  writer  elsewhere. 

The  Weed  Flora. — It  is  interesting  to  compare  Christy's  list  of 
weeds  with  those  collected  by  the  writer  thirty-six  years  later.  The 
country  was  comparatively  new  when  his  observations  were  made, 
and  the  list  is  short ;  it  may  be  incomplete  even  for  that  date.  The 
entrance  of  railways  into  this  territory,  however,  and  the  general 
settlement  and  cultivation  of  the  country,  no  doubt  greatly  in- 
creased the  number  of  introduced  weeds.  Some  of  the  native 
prairie  plants  given  in  the  Manitoba  list  have  also  become  weeds. 
They  are  discussed  as  "prairie  weeds"  in  the  preceding  article. 

The  following  species  of  introduced  weeds  were  found  chiefly 

along  the  roadbeds  of  the  railways  at  Carberry  and  MacGregor. 

With  them  were  associated  various  native  prairie  plants  but  mostly 

in  small  numbers.    Few  enter  the  prairie  transect  in  the  right  of 

way,  excepting  where  the  surface  has  been  disturbed.     The  list 

follows : 

Setaria  viridis  Sisymbrium    altissimum 

Phleum   pratense  Capsella  bursa-pastoris 

Avena  fatua  Trifolium   pratense 

Bromus    secalinus  Trifolium  hybridum 

Lolium  multiflorum  Melilotus  alba 

Polygonum  aviculare  Melilotus   officinalis 

Polygonum  convolvulus  Lathyrus  pratensis 

*Chenopodium  album  Linum  usitatissimum 

*Chenopodium  Bonus-Henricus  Lappula  echinata 

Salsola  Kali  Plantago  major 

tenuifolia  Plantago    lanceolata 

Amaranthus  retroflexus  Helianthus  annuus 

Silene  noctiflora  Tanacetum  vulgare 

*Saponaria  Vaccaria  Artemisia  Absinthium 

Portulaca  oleracea  Cirsium    arvense 

Thlaspi  arvense  Taraxacum  officinale 

Lepidium  virginieum  Taraxacum  erythrospermum 

Brassica  arvensis  Sonchus  arvensis 

Conringia  orientalis  Crepis  tectorum 

Those  marked  with  an  asterisk  were  reported  also  by  Christy. 
He  added  Lychnis  githago,  which  the  writer  did  not  find. 

While  these  weeds  have  freely  invaded  the  roadbed  and  the  cul- 
tivated fields  on  either  side,  they  are  excluded  by  the  unbroken 
prairie  turf  here  as  elsewhere.    Associated  with  these  weeds  on  the 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

roadbed  were  the  following  species  which  were  evidently  introduced 

from  some  other  part  of  the  country,  or  from  the  United  States : 

Poa  pratensis  Polanisia  trachysperma 

Potentilla  Anserina 

They  also  fail  to  enter  the  unbroken  prairie. 

The  prairie  flora  of  Manitoba  is  very  similar  to  that  of  Iowa  in 

identity  of  species,  and  it  is  quite  as  persistent. 

TABLE  OF  THE  PRAIRIE  FLORA 
The  following  list  includes  the  Manitoba  prairie  plants  which 

were  found  by  the  writer,  and  those  which  occur  on  the  sandy  areas 

are  also  noted. 

Column  I  includes  those  from  fertile  prairie  in  or  near  Carberry. 

Column  II  includes  those  from  sandy  prairie  near  Carberry. 

Column  III  includes  those  from  the  treeless  dune  areas  around  the 
Carberry  lobe. 

Column  IV  includes  those  from  the  fertile  prairie  near  MacGregor, 

Column  V  includes  the  prairie  species  also  reported  by  Christy. 
Those  marked  with  an  asterisk   (*)   are  not  known    from    the 

prairies  of  Iowa. 

The  nomenclature  of  Gray's  Manual  is  used  in  this  paper  ex- 
cepting in  the  case  of  the  few  species  not  included  in  that  work. 

In  such  cases  Britton's  Manual  is  followed. 

I  II  III  iv  v 

Family  Equisetaceae 

Equisetum  arvense 

Equisetum  hyemale  intermedium 
Family  Gramineae 

Andropogon  scoparius 

Andropogon  fureatus  — ( —  — j —  — j —  | __^_ 

Sorghastrum  nutans 

Panicum    Scribnerianum 

Panicum  virgatum 

*Stipa   viridula 

Stipa  comata 

Stipa  spartea  -j-  +  +  +  -j- 

Aristida   basiramea 

Muhlenbergia  racemosa 

Sporobolus  cryptandrus 

Sporobolus  heterolepis 

Sporobolus  brevifolius 

Agrostis    alba 

Agrostis  hyemalis 

Koeleria  cristata 

Bouteloua  oligostachya 

Bouteloua  hirsuta 

Bouteloua    curtipendula 

Poa   compressa 


+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

t 

+ 

+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

Festuca  octoflora 

Bromus  purgans 

Agropyron  Smithii 

Agropyron  tenerum 

Agropyron  caninum 

Agropyron  Eiehardsonii 

Hordeum  jubatum 

Elymus  canadensis 
Family  Cyperaceae 

Carex  straminea 
Family  Liliaceae 

Zygadenus  ehloranthus 

Allium  stellatum 

Lilium  philadelphicum 

Smilacina   stellata 
Family  Iridaceae 

Sisyrinehium  campestre 
Family  Salicaceae 

Salix  humilis 

Salix  rostrata 
Family  Fagaceae 

Corylus  americana 

Quercus   macrocarpa 
Family   Santalaceae 

Comandra  umbellata 

Comandra  pallida 
Family  Amaranthaceae 

Amaranthus  blitoides 
Family  Nyctaginaceae 

Oxybaphus    hirsutus 
Family  Caryophyllaceae 

Arenaria  stricta 

Cerastium    arvense 

*Lychnis  Drummondii 
Family  Manunculaceae 

*Thalictrum   confine 

Thalictrum    dasycarpum 

Anemone  patens  Wolfgangiana 

Anemone  cylindrica 

Anemone  canadensis 
Family  Cruciferae 

Lepidium    apetalum 

Sisymbrium  canescens 

Sisymbrium  canescens  brachycarpon 

Arabis   Drummondii 

Arabis    lyrata 

Arabis  glabra 

^Erysimum  parviflorum 

*Erysimum  asperum 
Family  Capparidaceae 

Cleome  serrulata 
Family  Saxifragaceae 

Heuchera   hispida 
Family  Bosaceae 

Spiraea  salicifolia 

Fragaria  virginiana 

Potentilla  arguta 

Potentilla  monspeliensis 


OP  MANITOBA 

33 

I 

II 

III 

IV 

V 

+ 

+ 

+ 

+ 

+ 

+ 

-t- 

+ 

+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

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+ 

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+ 

+ 

+ 

+ 
+ 

+ 

+ 
+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+' 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

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+ 

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+ 

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+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 
+ 

+ 

4- 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 


+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

34 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Potentilla  pennsylvanica 

*Potentilla  Hippeana 

Eosa  acicularis 

Rosa  pratincola 

Prunus  pumila 

*Prunus  Besseyi 
Family   Leguminosae 

Trifolium  repens 

Psoralea    argophylla 

Psoralea  eseulenta 

Amorpha  canescens 

Petalostemum  purpureum 

Petalostemum  candidum 

Astragalus  canadensis 

*Astragalus   adsurgens 

Oxytropis  Lamberti 

*Oxytropis  splendens 

Glycyrrhiza  lepidota 

Vicia  americana 

Vicia  americana  linearis 

Lathyrus   venosus 
Family  Linaceae 

Linum   rigidum 

Linum  sulcatum 
Family  Polygalaceae 

Polygala  Senega 
Family  Euphorbiaceae 

Euphorbia  serpyllifolia 
Family  Anacardiaceae 

Rhus   Toxicodendron 
Family  Violaceae 

Viola  pedatifida 
Family  Elaeagnaceae 

*Elaeagnus    argentea 
Family  Onagraceae 

Epilobium   angustifolium 

(Enothera    muricata 

(Enothera   biennis 

*CEnothera   pallida 

(Enothera   serrulata 

Gaura    coccinea 
Family  Umbelli ferae 

Zizia   aurea 

Zizia  cordata 
Family  Apocynaceae 

Apocynum  cannabinum 
Family  Asclepiadaceae 

Asclepias  speciosa 

Asclepias   ovalifolia 

Acerates  viridiflora 
Family  Convolvulaceae 

Convolvulus  sepium 
Family  Boraginaceae 

Lappula   Redowskii   occidentalis 

Lithospermum  canescens 

Lithospermum   angustifolium 
Family  Ldbiatae 

Teuerium  canadense 


I 

II 

III 

IV 

V 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

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+ 

+ 

+ 

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+ 

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+ 

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+ 
+ 

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+ 
+ 

+ 


+ 


+ 


+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 


PRAIRIE  FLORA  OF  MANITOBA 


35 


I 

II 

III 

IV 

V 

Agastache  Fcenieulum 

+ 

+ 

+ 

+ 

+ 

Draeocephalum  parviflorum 

+ 

+ 

Stachys  palustris 

+ 

+ 

Monarda  mollis 

+ 

+ 

+ 

+ 

+ 

Family  Solanaceae 

Physalis  virginiana 

+ 

+ 

+ 

+ 

Family  Scrophulariaceae 

Pentstemon    gracilis 

+ 

+ 

+ 

+ 

*Orthocarpus  luteus 

+ 

+ 

+ 

+ 

Pedicularis  canadensis 

+ 

+ 

Family  Eubiaceae 

Galium    boreale 

+ 

+ 

+ 

+ 

+ 

Houstonia   longifolia 

+ 

+ 

Family  Caprifoliaceae 

Symphoricarpos  occidentalis 

+ 

+ 

+ 

+ 

Symphoricarpos  racemosus  parviflorus  + 

Family  Campanulaceae 

Campanula   rotundifolia 

+ 

+ 

+ 

+ 

+ 

Family  Lobeliaceae 

Lobelia  spicata 

+ 

+ 

Family  Compositae 

Liatris  punctata 

+ 

+ 

+ 

+ 

Liatris  scariosa 

+ 

+ 

+ 

+ 

+ 

Chrysopsis  villosa 

+ 

+ 

+ 

+ 

+ 

Solidago    missouriensis 

+ 

+ 

+ 

+ 

Solidago   nemoralis 

+ 

+ 

+ 

+ 

Solidago  canadensis  gilvoeanescens 

+ 

+ 

+ 

Solidago  serotina 

+ 

+ 

Solidago  rigida 

+ 

+ 

+ 

+ 

+ 

Solidago   graminifolia 

+ 

+ 

+ 

Aster  novse-anglire 

+ 

+ 

+ 

+ 

Aster  Isevis 

+ 

+ 

+ 

+ 

+ 

Aster   multiflorus 

+ 

+ 

+ 

+ 

Aster  ptarmicoides 

+ 

+ 

+ 

+ 

+ 

*Erigeron  glabellus 

+ 

+ 

+ 

+ 

+ 

Erigeron   ramosus 

+ 

+ 

+ 

Erigeron    canadensis 

+ 

+ 

+ 

+ 

Antennaria  neodioica 

+ 

+ 

Antennaria  neglecta 

-f 

Iva  xanthifolia 

+ 

Ambrosia  psilostachya 

+ 

+ 

Heliopsis    seabra 

+ 

+ 

+ 

+ 

Eudbeckia    hirta 

+ 

+ 

+ 

+ 

Brauneria    angustifolia 

+ 

+ 

Lepachys  eolumnaris 

+ 

Helianthus    scaberrimus 

+ 

+ 

+ 

+ 

+ 

Helianthus  grosseserratus 

+ 

Helianthus  giganteus 

+ 

+ 

Helianthus    Maximiliani 

+ 

+ 

*Gaillardia   aristata 

+ 

+ 

+ 

+ 

Achillea  millefolium 

+ 

+ 

+ 

+ 

+ 

Artemisia    caudata 

+ 

+ 

+ 

+ 

Artemisia   dracuneuloides 

+ 

+ 

Artemisia  glauca 

+ 

+ 

Artemisia  ludoviciana 

+ 

+ 

+ 

+ 

+ 

Artemisia  frigida 

+ 

+ 

+ 

+ 

+ 

Cirsium    undulatum 

+ 

+ 

+ 

+ 

+ 

Lactuca   canadensis 

+ 

+ 

+ 

36  IOWA  STUDIES  IN  NATURAL  HISTORY 

I  II  III  IV 

Lactuca  pulchella 
Lygodesmia  juneea 
Agoseris  cuspidata 
*Agoseris  glauca 
Orepis  runcinata 
Prenanthes  racemosa 
Hieracium  canadense 


+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 
+ 
+ 

+ 

+ 

+ 

+ 

+ 

+ 

PLATE  V 


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PLATE   VI 


*■  iM$jhL&  is?  --*-*■(  #*k* -• 


Fig.  ].     A  bit  of  native  prairie  oji  the  west  side  of  CarberrY. 


Fig.  2.     Prairie  along  the  Canadian  Pacific  Railway  west  of  CarbeiTY, 

looking  west. 


PLATE  VII 


^fj&tit*** 


'  *v*  *4 


Fig.   1.      Sanely  prairie  at   Brandon   Junction. 


Fig.   2.     Spruce  Plain,  with   sandy  plain   and  -white  spruce. 


PLATE  VIII 


Fig.    1.      Dunes   east    of   Oarberry.      The   two   shadow-like   areas   are   plants 
of   Juniperux  ItoHzontalix.      Bur-oak  at   left   in  foreground. 


Fig.  2.     Dunes  east  of  Carberry,  showing   sandy  prairie  and  white  spruce. 


^■'J 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 

Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  6 

THE  MYOLOGY  OF  SPHENODON 
PUNCTATUM 

by 
Theodore  C.  Byerly 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


THE  MYOLOGY  OF  SPHENODON 
PUNCTATUM 

INTRODUCTION 

Due  to  the  generosity  of  Prof.  C.  C.  Nutting,  the  writer  was  al- 
lowed to  dissect  the  muscles  of  two  specimens  of  Sphenodon  punct(b- 
turn  which  were  brought  back  by  the  Fiji-New  Zealand  Expedition 
of  the  summer  of  1922.  These  specimens  are  of  special  interest  since 
they  belong  to  the  only  living  species  of  Rhyncocephalia,  the  lowest 
of  all  the  existing  orders  of  the  class  Reptilia.  The  species  is  rapidly 
becoming  extinct  and  careful  myological  studies  should  be  made 
while  it  is  still  existant.  Further  emphasis  is  placed  on  such  studies 
since,  according  to  Cope's  law  of  the  unspecialized :  "The  perfection 
produced  by  each  successive  age  has  not  been  the  source  or  parent 
of  future  perfection.  The  types  which  have  displayed  the  most 
specialized  mechanism  have  either  passed  away,  or,  undergoing  no 
change,  have  witnessed  the  progress  and  ultimate  supremacy  of  those 
which  were  once  their  inferiors. ' n 

Sphenodon  is,  of  all  living  reptiles,  probably  the  most  closely  allied 
to  the  amphibians  on  the  one  hand  and  the  higher  vertebrates  on 
the  other.  Since  this  is  true,  one  should  expect  Sphenodon  to  show 
more  or  less  transitional  stages  between  the  unspecialized  urodele 
condition  found  in  the  salamanders  and  the  specialized  form  of 
creatures  higher  in  rank  than  itself.  Cope  's  law  of  the  unspecialized 
seems  pretty  well  substantiated  by  paleontological  evidence,  and  it  is 
generally  accepted,  so  Sphenodon  should  possess  characters  very  like 
those  possessed  by  the  progenitors  of  birds  and  mammals.  Accord- 
ing with  this  hypothesis,  Sphenodon  is  very  primitive  in  all  its 
characters  and  no  less  so  in  its  musculature. 

Among  the  most  interesting  fields  in  myology  is  that  of  serial  and 
special  homology.  Necturus  has  been  used  as  the  base  form,  by  many 
workers,  for  determining  serial  and  special  homologies  in  limbed 
vertebrates  and  it  is  Necturus  which  has  been  used  as  a  basis  for 
such  conclusions  drawn  in  this  paper.    As  a  matter  of  fact,  there  is 

i  Cope,  E.D.,  Origin  of  the  Fittest,  p.  234. 

3 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

no  one  absolute  basis  for  determining  either  serial  or  special  homol- 
ogies, unless  it  would  be  through  a  series  of  models  prepared  from 
serial  sections  of  successive  embryonic  stages.  Even  these,  were 
they  available,  would  present  very  grave  difficulties.  However,  since 
nerve  supply  for  each  muscle  comes  from  the  somite  from  which  that 
muscle  was  derived,  the  nerve  supply  probably  furnishes  the  most 
reliable  criterion  for  the  determination  of  homology.  When  the 
nerve  supply  is  obscured  by  complex  branching  and  anastomosis,  as 
in  the  brachial  plexus,  muscle  insertion  must  aid  in  the  determina- 
tion of  homology.  Arterial  blood  supply,  origin  and  position  must 
sometimes  be  considered  but  can  by  no  means  be  regarded  as  reliable 
bases  for  judgment. 

Homology  of  the  muscles  of  the  proximal  portions  of  the  limbs 
has  long  been  a  controversial  subject  among  students  of  myology. 
It  is  hoped  that  a  critical  examination  of  the  muscles  of  Sphenodon 
may  contribute  something  to  the  solution  of  this  difficult  problem. 
Some  investigators  have  homologized  the  great  extensors  of  bra- 
chium  and  thigh  (Quain)  ;  while  others  (Owen)  homologize  the  ex- 
tensors of  the  brachium  with  flexors  of  the  thigh  and  vice  versa. 
The  difference  of  opinion  is  due  to  the  opposite  direction  of  flexion 
of  the  two  limbs.  The  condition  in  Sphenodon  is  somewhat  trans- 
itional between  the  unspeeialized  condition  in  the  limbs  of  Necturus 
and  the  stereotyped  stele-zeugopodial  articulation  in  the  higher  rep- 
tiles and  the  mammals. 

While  the  present  attempt  to  homologize  the  muscles  of  Sphenodon 
serially  in  the  limbs  and  especially  with  the  muscles  of  Necturus 
will  doubtless  leave  much  to  be  desired,  it  is  hoped  that  the  dissec- 
tions have  been  so  carefully  described  and  illustrated  by  diagrams 
that  they  will  furnish  a  reliable  basis  for  further  work.  This  is 
especially  true  because,  apparently,  very  few  men  have  availed  them- 
selves of  the  opportunity  actually  to  dissect  a  well-preserved  speci- 
men, and  undoubtedly  the  opportunity  will  become  rarer  as  the 
material  becomes  more  difficult  to  obtain. 

The  most  complete  description  of  the  muscles  of  Sphenodon  is 
that  of  Osawa.  This  paper  was  published  in  1899  and  may  be  found 
in  the  "Arehiv  fur  Mikroskopische  Anatomie,"  Bd.  51.  It  contains 
a  complete  description  of  the  muscles  and  their  nerve  supply  together 
with  a  partial  list  of  serial  and  special  homologies.  His  illustrations 
leave  much  to  be  desired  and  a  few  of  his  descriptions  are  incorrect. 

The  earliest  account  in  the  available  literature  is  that  of  Gunther, 


MYOLOGY  OP  SPHENODON  5 

published  in  1867.  His  account  is  accurate  but  covers  only  a  few  of 
the  limb  muscles  and  a  partial  dissection  of  the  intercostal  muscu- 
lature. He  took  his  nomenclature  from  anthropotomy  and  some  of 
his  special  homologies  will  hardly  stand.  Gadow,  1887  and  1890, 
published  very  thorough  accounts  of  the  caudal  musculature,  in- 
cluding both  drawings  and  discussion.  Furbringer's  paper,  1892, 
has  been  available  through  extracts  made  from  it  by  Gregory  and 
Camp  in  a  paper  published  in  the  "Bulletin  of  the  American 
Museum  of  Natural  History,' '  vol.  38.  Gegenbaur  (Leipzig,  1896) 
gives  an  account  of  the  integumental  musculature  of  the  head  and 
neck  (after  Ruge).  For  Necturits,  Wilder's  excellent  account  has 
been  the  chief  reference. 

Both  specimens  dissected  for  this  account  died  of  a  bone  and 
muscle  necrosis  diagnosed,  with  some  doubt,  as  osteo-myelitis.  The 
first  specimen  had  a  large  necrotic  mass  on  the  dorsum  of  the  left 
manus  and  the  carpals  of  that  member  were  nearly  destroyed ;  the 
symphysis  menti  was  also  destroyed.  After  death  it  was  skinned 
and  preserved  in  five  percent  formalin.  Dissection  brought  to  light 
other  necrotic  masses  in  the  m.  pectoralis,  in  the  liver  and  at  the 
juncture  of  a  regenerated  caudal  portion  with  the  original  body 
segments.  The  caudal  region  of  both  specimens  was  regenerated  for 
the  last  fourteen  or  fifteen  segments. 

The  second  specimen  became  very  ill  in  May  1923,  was  killed  and 
the  entire  body  was  fixed  in  chrom-aceto-formaldehyde  in  order  to 
preserve  the  tissues  for  histological  work.  The  symphysis  menti  was 
destroyed  by  necrosis  in  this  specimen. 

The  dissection  of  these  members  of  an  ancient  race,  occupying  so 
important  a  position  in  any  schema  of  the  sequence  of  forms  in  the 
course  of  organic  evolution,  and  so  nearly  extinct,  has  been  of  great 
interest.  Perplexing  differences  between  the  specimens  dissected 
and  the  work  of  other  men,  and  some  few  differences  between  other 
workers,  have  come  up  from  time  to  time  and  the  suggestions  of  Dr. 
F.  A.  Stromsten,  under  whom  this  work  was  undertaken,  have  been 
very  helpful  in  arriving  at  conclusions. 

THE  VISCERAL  MUSCLES 

The  visceral  muscles  are  located  in  the  head  and  neck.    They  arise, 

embryologically,    from  the   hypomeres   rather  than   the  epimeres. 

Phylogenetieally,  they  are  the  survivals  of  the  musculature  of  the 

gill  arches  of  lower  forms.    In  Sphenodon,  they  include  the  integu- 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

mental  and  facial  musculature,  the  intrinsic  muscles  of  the  hyoid 
and  larynx,  and  the  muscles  of  mastication. 

"Followings  the  lines  laid  down  by  Gegenbaur  in  his  'Lehrbuch  der  Ana- 
tomie  der  Menschen^  on  the  origin  of  the  facial  muscles,  G.  Euge  has  made 
detailed  researches  on  the  facial  musculature  of  lemurs,  from  which  he  arrives 
at  the  following  results: 

The  fact  that  all  the  muscles  supplied  by  the  facial  nerve  belong  to  the  same 
series  indicates  that  those  related  to  the  visceral  skeleton,  and  having  origin- 
ally nothing  to  do  with  the  face,  which  are  supplied  by  the  same  nerve,  must 
have  shifted  upwards  from  the  region  of  the  lower  jaw  and  neck,  so  as  to 
come  into  close  relation  with  the  soft  parts  surrounding  the  apertures  of  the 
ear  and  mouth,  that  is,  to  the  secondarily  formed  lips  and  to  the  external  ear. 
From  these  points,  they  extended  further,  taking  on  new  relations  to  the  eye, 
nasal  aperture  and  to  the  frontal  and  temporal  regions,  those  behind  it  from 
the  occipital  region.  The  upward  change  of  the  position  of  the  musculature 
thus  took  place  along  two  lines, — in  front  of,  and  behind  the  ear,  as  is  proved 
by  its  innervation,  .... 

....  The  platysma  myoides  thus  forms  the  matrix  for  the  facial  muscles, 
and  it  represents  the  remnants  of  a  musculature  continued  forward  to  the 
head,  which  has  retained  (e.g.  in  man)  an  undifferentiated  form  in  the  neck 
(Gegenbaur). 

Besides  the  platysma  myoides  there  is  a  second  deeper  dermal  system  of 
muscles  in  the  neck,  the  sphincter  colli.  This,  like  the  platysma,  also  takes  on 
secondary  relations  to  the  head,  and  gives  origin  to  the  levator  labii-superioris 
proprius,  levator  anguli  oris,  sphincter  oris,  buccinatorius  and  the  proper  mus- 
cles of  the  nose.    The  facial  muscles  not  named  here  arise  from  the  platysma. ' ' 

Gegenbaur3  mentions  the  facial  musculature  in  Sphenodon  in 
connection  with  Ruge  's  work  and  gives  one  text  figure. 

< '  Einen  sehr  primitiven  Zustand  bietet  der  Facialismuskulatur  bei  Sphenodon, 
wo  alle  Theile  noch  im  Zusammenhang  stehen.  An  den  noch  weit  oben  ent- 
springenden  Abductor  mandibulse  schlieben  sich  Zuga  (Sphincter  dorsalis)  die 
ventral  in  den  Intermandibularis  sich  f ortsetzen,  und  daran  reihen  sich  weiter 
abwarts  entspringende  Bundel,  welche  in  den  schwachen  Sphincter  colli  fort- 
gesetzt  sind." 

Sphenodon  presents,  in  the  adult,  a  very  primitive  condition  of 
the  facial  musculature.  Except  for  a  few  fibers  in  the  eyelids,  con- 
stituting an  orbicularis  oculi,  there  is  little  differentiation  of  the 
primitive  muscle  sheet.  This  sheet  is  continuous  ventrally  from  the 
shoulder  region  to  the  symphysis  menti.  The  posterior  portion  may 
be  termed  the  sphincter  colli  and  that  between  the  rami  of  the  man- 
dible, the  intermandibularis.    The  antero-dorsal  portion  is  contigu- 


2  Wiedersheim,  E.,  Comparative  Anatomy  of  Vertebrates,  p.  121. 

3  Gegenbaur,  C,  Vergleichende  Anatomie  der  Wirbelthiere,  p.  631. 


MYOLOGY  OF  SPHENODON  7 

ous  with  the  depressor  mandibular  (abductor  mandibulae  of  Gegen- 
baur)  and  passes  anterior  to  the  membrana  tympani;  Gegenbaur 
terms  this  the  sphincter  dorsalis. 

VISCERAL  MUSCLES  OF  THE  HYOID  REGION 

This  group  includes :  m.mylohyoideus,  m.stylohyoideus,  m.cerato- 
hyoideus  and  the  proper  muscles  of  the  larynx. 

Mylohyoideus 

This  muscle  lies  dorsal  to  the  anterior  portion  of  the  interman- 
dibularis  and  is  pretty  well  differentiated  from  it.  It  forms  a  thin 
but  strong  sheet  of  muscle  fibers  which  stretches  between  the  anterior 
third  of  the  rami  of  the  mandibles.  With  the  intermandibularis,  it 
serves  to  raise  the  floor  of  the  mouth. 

Innervation:  N.  trigeminus. 

Stylohyoideus 

This  is  a  very  small  muscle  that  stretches  from  the  styloid  process 
to  the  lateral  border  of  the  posterior  portion  of  the  cerato-hyal; 
levator  of  the  hyoid. 

Innervation:  N.  facialis. 

Ceratohyoideus 

This  muscle  lies  between  the  lateral  border  of  the  geniohyoideus 
and  the  mesial  surface  of  the  pterygoideus  internus.  It  extends 
from  the  anterior  border  of  the  posterolateral  portion  of  the  hyo- 
hyoid  to  the  mesial  part  of  the  antero-lateral  portion  of  the  cerato- 
hyoid. 

Innervation:  N.  facialis. 

MUSCLES  OF  THE  LARYNX 

These  muscles  present  no  specialization  in  Sphenodon;  they  con- 
sist of  a  single  constrictor  and  a  pair  of  dilators. 

DlLATORES  LARYNGEI 

These  consist  of  a  pair  of  muscles,  one  on  either  side  of  the  larynx. 
Each  extends  from  its  origin  on  the  cricoid  to  its  insertion  on  the 
antero-lateral  surface  of  the  arytenoid.  By  abduction  of  the  ary- 
tenoids, they  serve  as  dilators  of  the  larynx  in  inspiration. 

Constrictor  laryngeus 
Except  for  a  very  short  distance  on  the  mid-dorsal  surface,  this 
muscle  completely  surrounds  the  larynx.    It  covers  almost  the  entire 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

surface  of  the  arytenoid  cartilages  from  which  its  fibers  are  exserted 
and  into  which  they  are  inserted. 
Innervation :  N.  vagus. 

MUSCLES  OF  MASTICATION 

Sphenodon  is  largely  predaceous  in  its  food  habits.  It  eats  lizards, 
bones  and  all,  so  one  might  expect  to  find  rather  heavy  muscles  of 
mastication.  The  jaws  are  very  strongly  muscled,  the  pterygoideus 
internus  being  exceptionally  heavy.  The  group  consists  of  three 
adductors,  m.  temporo-massetericus,  m.  pterygoideus  externus, 
m.  pterygoideus  internus  and  a  single  abductor,  m.  depressor  man- 
dibular 

Temporo-massetericus 

This  muscle  is  homologous  with  both  the  temporalis  and  the  mas- 
setericus  of  more  specialized  animals.  It  forms  a  heavy  muscle  mass 
which  lies  beneath  the  superficial  fascia  and  the  temporal  arcade  on 
the  postero-lateral  surface  of  the  head. 

Origin :  From  the  fascia  which  covers  the  lateral  temporal  fossa 
and  from  the  inner  surfaces  of  the  squamosal,  jugal  and  postorbital 
bones,  its  fibers  extend  ventrally  to  their 

Insertion :  As  muscle  fibers,  on  the  coronoid  process  and  the  sub- 
jacent dorso-lateral  surfaces  of  the  dentary  and  supra-angular  bones. 
There  is  some  indication  of  division  into  external  and  internal  mass- 
es at  the  point  of  insertion. 

Action :  Closes  the  mouth ;  it  is  most  efficient  when  the  mouth  is 
almost  closed. 

Innervation :  N.  trigeminus. 

Pterygoideus  externus 

This  muscle  is  not  sharply  defined  from  the  preceding  but  its 
fibers  run  at  a  somewhat  different  angle.  It  lies  just  beneath  the 
temporo-massetericus. 

Origin:  From  the  inner  surface  of  the  postorbital,  the  lateral 
surface  of  the  epipterygoid,  and  from  the  fascia  which  covers  the 
supratemporal  fossa,  its  fibers  extend  postero-laterally  to  their 

Insertion :    On  the  dorso-mesial  surface  of  the  supra-angular. 

Action:  Aids  in  closing  the  mouth  and  in  the  grinding  action 
when  the  mouth  is  almost  closed. 

Innervation:  N.  trigeminus. 

Pterygoideus  internus 
This  is  the  heaviest  and  most  powerful  of  the  muscles  of  mastica- 


MYOLOGY  OF  SPHBNODON  9 

tion.  It  is  the  innermost  of  the  group  and  forms  a  large  rounded 
protuberance  into  the  mouth  cavity. 

Origin :  From  the  basi-sphenoid,  the  parietal,  the  pterygoid  and 
from  the  fascia  covering  the  supra-temporal  fossa. 

Insertion :    On  the  ventral  and  lateral  surfaces  of  the  dentary. 

Action :  Abductor  of  the  mandible,  most  efficient  when  the  mouth 
is  widely  gaping. 

Innervation:  N.  trigeminus. 

Depressor  mandibul^s 

This  muscle  follows  the  posterior  contour  of  the  squamosal  and 
lies  just  beneath  the  sphincter  colli,  except  in  the  region  near  the 
dorsal  mid-line  where  it  is  covered  by  the  aponeurosis  of  the  cranial 
portion  of  the  trapezius. 

Origin :  From  the  dorsal  portion  of  the  posterior  surface  of  the 
squamosal  and  the  lateral  portion  of  the  posterior  surface  of  the 
parietal. 

Insertion :   On  the  posterior  and  ventral  surfaces  of  the  articulare. 

Action :    Abductor  of  the  mandible. 

Innervation:  N.  facialis. 

THE  AXIAL  MUSCULATUEE 

The  axial  musculature  of  Sphenodon  is  perhaps  more  significant 
than  the  appendicular.  The  intercostal  system  is  almost  as  complex 
as  that  of  the  Ophidia,  due  to  the  presence  of  movable  and  perhaps 
functional  ribs  or  gastralea  on  the  abdominal  surface.  The  muscles 
that  function  in  respiration  show  many  characters  transitional  be- 
tween the  simple  Urodele  type  and  the  condition  found  in  the  more 
specialized  reptiles.  A  m.  triangularis  sterni  is  differentiated  from 
the4  transversalis  sheet ;  this  fact  is  one  of  many  which  may  serve  to 
indicate  that  Sphenodon  is  very  close  to  both  bird  and  mammal  forms 
in  its  myology. 

The  usual  differentiation  into  dorsal  and  ventral  groups  is  quite 
marked.  The  following  muscles  have  been  considered  as  belonging 
to  the  ventral  axial  group  but  there  are  a  few  others,  discussed  under 
the  trunco-zonal  muscles  of  the  appendicular  group,  which  might 
be  considered  here :  m.  geniohyoideus,  m.  genioglossus,  m.  hyoglossus, 
m.  cleido-episterno-hyoideus,  m.  omohyoideus,  m.  sterno-coracoideus 

*  In  discussing  the  myology  of  birds,  Wiedersheim  says ;  ' '  External  and  in- 
ternal intereostals  are  well  developed,  and  a  triangularis  sterni  appears  for  the 
first  time  on  the  inner  surface  of  the  sternal  ends  of  the  ribs."  Wiedersheim, 
B.,  Comparative  Anatomy  of  Vertebrates,  p.  140. 


10  IOWA  STUDIES  IN  NATURAL  HISTOKY 

superficialis,  m.  sterno-eoracoideus  profundus,  m.  costo-sterno-scapu- 
laris,  m.  costo-eoraeoideus,  m.  serratus  posterior,  m.  serratus  an- 
terior, m.  rectus  abdominis  externus,  m.  rectus  abdominis  internus, 
m.  obliquus  externus,  m.  obliquus  internus,  m.  transversalis  abdom- 
inis, m.  triangularis  sterni,  mm.  intercostales  externi  longi,  mm. 
uncini-costales  longi,  mm.  uncini-costales  breves,  mm.  intercostales 
externi  breves,  mm.  intercostales  interni  breves,  mm.  intercostales 
interni  longi,  mm.  intercostales  ventrales,  mm.  abdomino-costales, 
m.  longus  colli,  m.  ilio-sacro-costo-costalis,  m.  ilio-ischio-eaudalis. 

Geniohyoideus 

Origin :  From  the  inner  surface  of  the  mandible,  from  a  space  a 
quarter  inch  in  width  just  laterad  of  the  symphysis.  Its  fibers  ex- 
tend caudad  beneath  the  intermandibularis  to  their 

Insertion :    On  the  anterior  border  of  the  medial  half  of  the  hyoid. 

Action:  Draws  the  hyoid  forward;  perhaps  aids  in  protrusion 
of  the  tongue. 

Genioglossus 

Origin :  From  the  inner  surface  of  the  mandible,  just  dorsal  to 
the  origin  of  the  geniohyoideus. 

Insertion :  On  the  ventral  surface  of  the  tongue ;  its  fibers  mingle 
with  those  of  the  lingualis. 

Action :    Aids  in  manipulation  and  protrusion  of  the  tongue. 

Hyoglossus 

Origin:  From  the  anterior  border  of  the  hyoid,  beneath  the 
middle  portion  of  the  geniohyoid.  Its  fibers  extend  anteriorly  to  their 

Insertion :  On  the  ventral  surface  of  the  tongue,  about  an  inch 
from  the  tip. 

Action :  It  serves  as  a  retractor  of  the  tongue,  opposing  the  action 
of  the  geniohyoideus. 

These  three  muscles  have  been  discussed  with  the  ventral  axial 
muscles  in  spite  of  the  fact  that  they  are  frequently  considered  with 
the  visceral  muscles.  Wilder5  makes  the  following  statement :  ' l  The 
musculature  of  the  tongue,  especially  its  extrinsic  muscles,  such  as 
hyoglossus,  genioglossus,  styloglossus,  etc.,  is  probably  derived  from 
the  visceral  muscles,  .  .  ."  On  the  other  hand,  Ecker,6  in  describ- 
ing the  course  of  the  hypoglossal  nerve  in  the  frog,  states:  "N. 
hypoglossus  or  n .  spinalis  I.  (A)  —  (B)  —  (C)    When  near  the  glosso- 


5  Wilder,  H.H.,  History  of  the  Human  Body,  p.  216. 
e  Ecker,  A.,  Anatomy  of  the  Frog,  p.  182. 


MYOLOGY  OF  SPHENODON  11 

pharyngeal  it  supplies  twigs  to  the  geniohyoideus,  sternohyoideus 
and  omohyoideus.  (D)  One  of  the  branches  passes  inward  to  supply 
the  hyoglossus."  Sobotta,7  in  his  work  on  human  anatomy,  says: 
"The  geniohyoid  is  supplied  by  fibers  from  the  first  and  second 
spinal  nerves  which  accompany  the  hypoglossal  nerve. ' '  In  Spheno- 
don,  the  hypoglossal  furnishes  the  nerve  supply  for  the  geniohyoi- 
deus, genioglossus  and  hyoglossus.  Since  the  n.  hypoglossus  is  not 
yet  established  as  one  of  the  cranial  nerves  in  the  Anura,  and  since 
it  does  not  supply  a  branchial  arch  at  any  time,  it  seems  logical  to 
assume  that  in  Sphenodon  those  muscles  which  it  supplies  should 
be  considered  with  the  ventral  axial  muscles. 

If  this  postulate  be  accepted,  there  is  in  Sphenodon,  as  one  might 
expect  in  a  primitive  form  so  close  to  the  Urodeles,  an  almost  un- 
broken, ventral,  longitudinal  muscle  sheet  extending  from  the  pos- 
terior border  of  the  ischiadic  plate  to  the  symphysis  menti.  It  in- 
cludes the  following  muscles  which  are  probably  serially  homologous : 
m.  geniohyoideus,  m.  hyoglossus,  m.  genioglossus,  m.  eleido-episterno- 
hyoideus,  m.  sterno-coracoideus  superficialis,  m.  sterno-coracoideus 
profundus,  m.  rectus  abdominis  externus,  m.  rectus  abdominis 
internus. 

CLEIDO-EPISTERNO-HYOIDEUS 

This  is  a  thin  muscle  which  covers  most  of  the  ventral  surface  of 
the  oesophagus  and  trachea.  Its  fibers  run  postero-anteriorly  just 
beneath  omohyoideus  and  the  sphincter  colli. 

Origin :  From  the  anterior  border  of  the  mesial  half  of  the  clavicle 
and  from  the  whole  anterior  border  of  the  episternum. 

Insertion :  On  the  posterior  border  of  the  lateral  half  of  the  hyoid 
cartilage,  beneath  and  lateral  to  the  insertion  of  the  omohyoideus. 

Action :    Eetractor  of  the  hyoid. 

Omohyoideus 

This  muscle  and  the  preceding  one  act  as  depressors  and  re- 
tractors of  the  hyoid,  thus  serving  to  oppose  the  action  of  the  genio- 
hyoideus and  ceratohyoideus  and  to  maintain  a  stable  point  of  origin 
for  the  hyoglossus. 

Origin:  It  takes  origin  from  the  antero-medial  portion  of  the 
mesial  surface  of  the  scapula,  just  dorsal  to  the  articulation  of  that 
bone  with  the  clavicle,  and  from  the  scapulo-coracoid  ligament.    It 


7  Sobotta,  J.,  Atlas  and  Textbook  of  Anatomy,  p.  212. 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

curves  ventro-anteriorly  passing  dermad   of  the  cleido-episterno- 
hyoideus  to  its 

Insertion :    On  the  medial  surface  of  the  hyoid. 

Sterno-coracoideus  superficialis 
The  various  elements  of  the  pectoral  girdle  are  not  fused  to  form 
a  solid,  inflexible  unit  in  Sphenodon  as  they  are  in  the  Anura  and 
the  more  highly  specialized  reptiles.  The  sternum  and  coracoid  are 
quite  free  from  each  other  as  far  as  bony  or  cartilaginous  connections 
are  concerned.  The  T-shaped  episternum  (interclavicularis)  an- 
chors the  clavicles,  coracoids  and  sternum  rather  loosely  in  place 
but  permits  a  considerable  amount  of  interplay.  This  interaction 
is  controlled  in  part  by  the  sterno-coracoideus  superficialis. 

Origin :    It  takes  origin  from  the  medial  half  of  the  extreme  pos- 
terior portion  of  the  inner  surface  of  the  sternum.    Its  fibers  extend 
in  a  thin  sheet  about  a  half  inch  in  width,  antero-laterally  to  their 
Insertion :    On  the  coracoid,  along  the  medial  border  of  the  epi- 
coraco-humeralis. 

Sterno-coracoideus  profundus 

This  muscle  lies  just  ventral  to  the  sterno-coracoideus  superficialis 
but  is  somewhat  wider,  extending  laterally  to  fuse  with  the  costo- 
coracoideus.  Together  with  the  muscle  just  described,  it  aids  in  re- 
traction of  the  coracoid  and  unification  of  the  pectoral  girdle. 

Origin:  From  the  anterior  border  of  the  sternum,  beneath  the 
sterno-coracoideus  superficialis.    Its  fibers  extend  cephalad  to  their 

Insertion :  Ventral  and  mesiad  to  those  of  the  sterno-coracoideus 
superficialis,  along  the  medial  border  of  the  epicoraco-humeralis. 

COSTO-STERNO-SCAPULARIS 

This  muscle  is  probably  serially  homologous  with  the  inter- 
costales  ventrales. 

Origin :  From  the  anterior  border  of  the  first  complete  rib,  just 
ventral  to  the  ventro-mesial  curvature  of  that  rib ;  it  extends  ceph- 
alad to  its 

Insertion:  On  the  dorsal  third  of  the  sterno-scapular  ligament 
and  thence  on  the  mesial  surface  of  the  ventral  portion  of  the 
scapula. 

Action :    Retractor  of  the  scapula,  compressor  of  the  ribs. 

COSTO-CORACOIDEUS 

This  muscle  lies  mesial  to  the  costo-sterno-scapularis  beneath  the 


MYOLOGY  OF  SPHENODON  13 

sterno-eoracoideus  superficial,  and  lateral  to  the  sterno-coracoideus 
profundus. 

Origin :  It  takes  origin  from  the  anterior  border  of  the  first  com- 
plete rib,  just  mesial  to  the  origin  of  the  costo-sterno-scapularis.  It 
extends  cephalad  to  its 

Insertion :  On  the  mesial  face  of  the  coracoid,  between  the  junc- 
tion of  the  subscapular  and  the  coracoid  heads  of  the  subscapulo- 
coraco-humeralis. 

Action :    Eetractor  of  the  scapula,  compressor  of  the  ribs. 

Rectus  abdominis  externus 

This  muscle  is  divided  into  segments  by  the  abdominal  ribs  and 
is  further  indistinctly  divided  into  a  superficial  and  a  deeper  layer. 
The  external  layer  has  many  fibers  which  insert  into  the  integument. 

Origin :  This  muscle  takes  origin  from  the  whole  posterior  border 
of  the  ischium.  It  is  a  little  difficult  to  say  certainly  which  end  of 
this  muscle  is  its  origin  and  which  its  insertion  but  since  the  pelvic 
girdle  is  more  or  less  firmly  fixed  and  the  pectoral  girdle  is  flexible, 
the  origin  as  stated  is  the  more  probable.  It  extends  anteriorly  over 
the  origin  of  the  pubo-ischio-tibialis  and  continues  to  its 

Insertion :    On  the  entire  posterior  border  of  the  sternum. 

Rectus  abdominis  internus 

Origin :  It  takes  origin  from  the  lateral  tuberosity  of  the  pubis 
and  from  an  accessory  ligament  which  extends  between  the  rectus 
abdominis  externus  and  the  pubo-ischio-tibialis  to  the  pubic  sym- 
physis.   It  extends  antero-mesially  to  its 

Insertion :  On  the  internal  midline  of  the  abdominal  ribs  and  on 
the  inner  surface  of  the  rectus  abdominis  externus. 

Obliquus  externus 

The  obliquus  externus  forms  a  continuous  sheet  from  the  pelvic 
girdle  anterior  to  the  first  or  second  rib,  where  it  becomes  modified 
to  form  a  part  of  the  serratus  group.  It  is  indistinctly  divided  into 
a  superficial  and  a  deep  layer,  the  fibers  of  both  running  in  the  same 
direction  and  having  almost  the  same  origin  and  insertion. 

Origin :  By  digitations  from  each  of  the  complete  ribs,  after  the 
second,  and  from  the  lumbar  fascia;  the  fibers  of  both  sheets  pass 
ventro-laterally  to  their 

Insertion :  By  muscle  fibers  on  each  of  the  abdominal  ribs  and  by 
a  strong  ligament  on  the  lateral  tuberosity  of  the  pubis  laterad  to 
the  rectus  internus. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

Obliquus  internus 

The  obliquus  internus  shows  very  clearly  that  it  has  only  recently, 
phylogenetically  speaking,  been  broken  into  transversalis  and 
obliquus.  It  does  not  form  a  complete  sheet  over  the  entire  inner 
abdominal  wall,  but  covers  only  the  dorso-mesial  portion  of  it.  It 
lies  just  retro-peritoneal  and  the  peritoneum  adheres  very  closely 
to  it. 

Origin :  By  tendinous  digitations  from  the  centra  of  each  of  the 
vertebrae  from  the  tenth  to  the  twenty-fifth.  It  extends  antero- 
laterally  to  its 

Insertion :  By  muscle  fibers  on  each  of  the  complete  ribs,  for  a 
space  about  a  quarter  inch  in  length  on  the  posterior  border,  about 
an  inch  laterad  from  the  centrum  and  two  intercostal  spaces  anterior 
to  the  vertebra  of  origin. 

Transversalis  abdominis 

The  transversalis  abdominis  sheet  lies  lateral  to  the  obliquus  in- 
ternus and  just  beneath  the  peritoneum,  except  at  the  anterior  end 
where  it  passes  behind  the  triangularis  sterni.  The  peritoneum  ad- 
heres to  it  very  tightly. 

Origin :  From  each  of  the  complete  ribs  by  digitations  which  take 
origin  just  lateral  to  the  insertions  of  the  obliquus  internus  and 
from  the  lumbar  fascia  in  the  lateral  line  region.  The  fibers  extend 
ventrally  to  their 

Insertion :  On  the  peritoneum  along  a  very  even  line  just  at  the 
ventro-internal  terminations  of  the  costse  and  on  the  sternum,  just 
laterad  to  the  insertion  of  the  triangularis  sterni. 

Triangularis  sterni 

This  muscle  forms  a  sheet  about  a  half  inch  in  width  just  mesiad 
from  the  transversalis  sheet.  Its  presence  has  not  been  recorded  by 
others  who  have  worked  on  Sphenodon  but  it  forms  a  very  distinct 
muscle  whose  fibers  cross  those  of  the  transversalis  abdominis  in  a 
markedly  distinct  direction, 

Origin :  It  takes  origin  from  the  last  incomplete  rib,  that  of  the 
eighth  vertebra,  and  from  the  first  complete  rib,  from  the  postero- 
medial border  between  the  insertion  of  the  obliquus  internus  and 
the  origin  of  the  transversalis  abdominis. 

Insertion :  On  the  inner  surface  of  the  sternum,  along  the  lateral 
border  of  the  sterno-coracoideus  profundus. 


MYOLOGY  OF  SPHENODON  15 

MUSCLES  OF  THE  EIBS  AND  SCUTES 
There  is  some  difference  of  opinion  among  men  who  have  worked 
on  Sphenodon  as  to  the  use  or  non-use  of  the  ventral  scutes  in  loco- 
motion. From  observation  of  the  movements  of  the  creatures  it 
would  seem  that  they  may  use  these  scutes  as  auxiliary  means  of 
movement.  This  observation  is  much  strengthened  by  dissection  of 
the  musculature.  The  abdomino-costales  tilt  the  scutes  so  that  they 
form  an  efficient  friction  surface.  Contraction  of  the  external 
oblique  series  of  muscles  would  slowly  project  the  body  forward, 
using  the  scutes  as  fixed  points  by  their  contact  with  the  ground. 
Since  Sphenodons  inhabit  burrows,  this  action  would  be  of  consider- 
able service  to  them  in  progress  through  narrow  places  where  use 
of  the  limbs  would  be  impeded. 

Intercostales  externi  longi 

Just  beneath  the  obliquus  externus  lie  two  sets  of  semisegmental 
muscles  whose  fibers  run  in  the  same  direction  as  those  of  the  obliquus 
externus.  The  more  ventral  series,  which  consists  of  the  intercostales 
longi,  is  rather  irregular  in  occurrence  but  fairly  regular  in  form. 

Origin :  It  is  formed  by  a  number  of  slips,  each  of  which  rises  from 
the  posterior  border  of  the  lower  medial  portion  of  a  rib,  extends 
backward  and  downward  over  the  rib  next  posterior  to  its  origin 
to  its 

Insertion:  On  the  anterior  border  of  the  second  rib  posterior 
from  the  origin,  just  dorsal  to  the  antero-ventral  curvature  of  that 
rib.  Such  slips  do  not  rise  regularly  from  every  rib  but  do  so  fairly 
regularly  from  the  more  anterior  ribs,  after  the  first,  and  less  regu- 
larly from  the  more  posterior. 

Ungino-costales  longi 

This  muscle  sheet  forms  the  dorsal  series  of  the  second  layer  of 
the  oblique  musculature. 

Origin :  Each  slip  rises  from  the  posterior  border  of  the  proximal 
half  of  an  uncinate  process  and  a  small  area  of  the  rib  adjacent. 
Each  slip  extends  postero-ventrally  over  the  rib  next  posterior,  to  its 

Insertion :  On  the  rib  second  posterior  to  the  origin,  just  dorsal 
to  the  insertion  of  the  intercostales  externi  longi. 

Uncino-costales  breves 
This  series  is  rather  more  regular  in  form  and  occurrence  than 
the  two  preceding  but,  belonging  to  the  same  muscle  layer,  forms  a 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

third  series  of  semisegmental  muscles,  each  slip  of  which  extends 

from  its 

Origin :    On  the  ventral  border  of  an  uncinate  process  to  its 
Insertion :    On  the  lateral  border  of  the  rib  next  posterior  to  its 

origin,  on  a  space  about  a  fourth  inch  in  length  just  ventral  to  the 

uncinate  process. 

Intercostales  externi  breves 
These  muscles   form  the   usual  thin   sheet  with   fibers  running 
diagonally  dorso-ventral  from  the  posterior  border  of  one  rib  to  the 
anterior  border  of  the  one  next  posterior. 

Abdomino-costales 
Slips  from  the  inner  surface  of  the  rectus  abdominis  and  from  the 
gastralea  attach  to  the  posterior  border  of  the  external  surface  of 
the  ventral  portion  of  each  rib. 

Intercostales  ventrales 
The  ventral  portions  of  the  intercostal  spaces  are  without  fibers 
of  the  intercostales  externi  breves.  Ventral  to  the  sharp  antero- 
ventral  curvature  of  the  ribs,  many  loosely  bound  fascicles  of  muscle 
fibers  extend  from  one  rib  to  the  next.  These  fascicles  run  from  a 
higher  posterior  origin  to  a  slightly  lower  anterior  insertion  on  the 
next  rib.  Some  of  these  fibers  traverse  the  outer  surface  of  the  rib 
of  their  insertion  to  insert  on  its  anterior  border. 

Intercostales  interni  breves 
This  muscle  sheet  might  be  construed  to  include  the  intercostales 
ventrales.    Its  fibers  traverse  the  intercostal   spaces  in  the  same 
direction  but  dorsal  to  the  preceding.    They  lie  just  internal  to  the 
intercostales  externi  breves. 

Intercostales  interni  longi 

This  series  consists  of  a  slip  for  each  rib  after  the  second.  A  stout 
tendinous  sheet  from  the  ilium  serves  as  origin  for  the  slips  to  the 
last  two  ribs. 

Origin :  The  muscle  slips  comprising  this  muscle  take  origin  from 
the  anterior  border  of  each  rib  for  a  space  about  a  half  inch  long 
just  below  the  point  of  origin  of  the  ilio-sacro-costo-costalis  slip  and 
the  insertion  of  the  obliquus  internus  slip  and  then  run  antero- 
ventrally  to  their 


MYOLOGY  OP  SPHENODON  17 

Insertion:  On  the  posterior  border  of  the  rib  second  anterior 
from  the  rib  of  origin,  just  dorsal  to  the  antero-ventral  curvature 
of  that  rib. 

Respiration  in  Sphenodon 

The  change  from  aquatic  to  terrestrial  habits  required,  of  course, 
considerable  readjustment  of  the  trunk  musculature  to  make  lung 
breathing  possible.  The  Urodeles,  living  a  sluggish  semi-aquatic 
life,  are  never  more  than  partially  dependent  on  their  lungs  for 
oxygen  supply,  and  as  a  consequence  need  very  little  specialization 
for  lung  breathing.  Even  in  the  more  active  Anura,  which  charac- 
teristically spend  a  major  portion  of  their  adult  existence  on  land, 
most  of  the  oxygen  supply  is  obtained  through  the  skin  and 
oesophago-pharyngeal  surfaces.  Not  until  the  dry  skinned,  terres- 
trial dwelling  reptiles  are  reached  in  the  phylogenetic  scale,  do  the 
lungs  assume  a  role  of  major  importance  in  respiration. 

Sphenodon  is  the  most  primitive  of  the  existing  Reptilia ;  so  one 
might  postulate  that  in  Sphenodon  might  be  found  a  situation  al- 
most exactly  transitional  between  the  Amphibia  and  the  higher 
terrestrial  vertebrates.  This  is  exactly  the  condition  they  present 
in  dissection.  Instead  of  a  simple  segmented  muscle  sheet  forming 
the  body  wall,  there  appears  quite  an  intricate,  but  not  wholly  regu- 
lar group  of  series  of  muscle  slips  which  act  as  levators  and  de- 
pressors of  the  ribs. 

The  following  muscles  act  as  levators  of  the  ribs:  m.  obliquus  ex- 
ternus,  mm.  uncini-costales  breves,  mm.  uncini-costales  longi,  mm. 
intercostales  externi  longi,  mm.  intercostales  externi  breves. 

They  are  opposed  by  the  following  depressors  and  compressors 
of  the  ribs :  depressors ;  mm.  intercostales  interni  breves,  mm.  inter- 
costales interni  longi,  m.  obliquus  internus,  mm.  intercostales  ven- 
trales;  compressors;  m.  triangularis  sterni,  m.  transversalis  abdo- 
minis. The  rectus  abdominis  internus  may  aid  in  respiration  as  a 
compressor  of  the  body  cavity. 

Since  both  specimens  had  already  been  used  in  the  preparation 
of  a  paper  on  the  digestive  system,  a  careful  study  of  the  diaphragm 
was  impossible.  As  far  as  could  be  ascertained,  it  was  incomplete 
and  not  muscular. 

Longus  COLLI 
Origin:     From  the  ventral  surfaces  of  vertebrae  two  to  twelve 
inclusive  and  from  their  transverse  processes,  a  slip  from  the  rib  of 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  seventh  vertebra ;  it  extends  eephalad,  just  lateral  to  the  median 
line,  to  its 

Insertion :  On  the  ventral  surfaces  of  the  axis  and  the  occipital 
condyle. 

Action :  Aids  in  lateral  movements  of  the  head  and  in  holding  it 
erect. 

Ilio-sacro-costo-costalis 

Origin :  From  the  ilium,  the  sacrum,  the  ribs,  and  by  fibers  from 
the  longus  colli. 

Insertion :  On  the  transverse  processes  and  centra  of  all  the  ver- 
tebrae anterior  to  the  sacrum. 

Action :    Flexor  and  tensor  of  the  trunk. 

Remarks:  This  muscle  seems  to  be  unique  in  its  continuation 
anteriorly  beneath  the  ribs.  Its  posterior  portion  is  probably  hom- 
ologous with  the  quadratus  lumborum  of  higher  forms. 

Ilio-ischio-caudalis 

Origin :  From  the  ilium,  the  ischium  and  from  the  ventral  sur- 
faces of  the  transverse  processes  of  the  caudal  vertebrae. 

Insertion :  On  the  transverse  and  haemal  processes  of  the  caudal 
vertebrae. 

Action :    Abductor-adductor  of  the  tail. 

DORSAL  AXIAL  MUSCLES 

This  group  includes  all  the  axial  muscles  dorsal  to  the  lateral  line 
and  above  the  ribs.  These  muscles  are  not  in  all  cases  clearly  sep- 
arated from  one  another  and  their  description  is  somewhat  prob- 
lematical, their  designation  more  or  less  arbitrary.  The  group  is 
customarily  divided  into  a  median  and  a  lateral  portion ;  this  plan 
has  been  followed  as  far  as  practicable.  The  medial  group  includes 
the  m.  semispinalis  capitis,  m.  transverso-spino-spinalis,  mm.  inter- 
spinales.  The  lateral  group  includes  the  m.  cervico-capitis,  m.  sacro- 
transverso-transversalis,  m.  caudae  dorsalis,  m.  obliquus  capitis,  m. 
rectus  capitis  posticus. 

Medial 

Semispinalis  capitis 
Origin :    From  the  antero-lateral  surfaces  of  the  spinous  processes 
of  the  fourth  to  eighth  cervical  vertebrae  inclusive,  it  runs  eephalad 
to  its 


MYOLOGY  OF  SPHENODON  19 

Insertion :  On  the  dorsal  portion  of  the  posterior  surface  of  the 
parietal. 

Action :    Aids  in  lateral  and  dorsal  movements  of  the  head. 

Transverso-spino-spinalis 

Origin :  This  muscle  receives  many  fibers  from  the  sacro-trans- 
verso-transversalis  from  which  it  is  not  sharply  defined.  Most  of 
its  fibers  take  origin  from  the  spinous  processes  of  vertebrae  three 
to  twenty-six  and  from  the  proximal  portions  of  their  transverse 
processes. 

Insertion :  The  deepest  layer  of  fibers  inserts  on  the  spinous  pro- 
cess of  the  vertebra  second  anterior  to  their  origin ;  the  fibers  of  the 
middle  layer  skip  two  vertebrae  to  insert  on  the  spinous  process  of 
the  vertebra  third  anterior  from  their  point  of  origin ;  the  fibers  of 
the  superficial  layer  unite  with  fibers  of  the  sacro-transverso-trans- 
versalis  and  insert  on  the  vertebra  sixth  anterior  to  their  origin. 

Action :    Serves  as  a  flexor  of  the  body. 

Interspinals 

Origin :  From  the  anterior  surfaces  of  the  spinous  processes  of 
all  the  vertebrae. 

Insertion :  On  the  posterior  border  of  the  spinous  process  of  the 
vertebra  next  anterior  to  the  point  of  origin. 

Caudle  dorsalis 

Origin:  There  is  no  break  between  this  muscle  and  the  sacro- 
transverso-transversalis  but  its  position  makes  separate  consider- 
ation necessary.  It  takes  origin  from  the  sacrum,  the  ilium,  and  the 
spinous  and  transverse  processes  of  the  caudal  vertebrae  and  extends 
caudad  to  its 

Insertion :  On  the  spinous  and  transverse  processes  of  the  caudal 
vertebrae. 

Action :    Flexor  of  the  tail. 

Lateral 

Cervico-capitis 

Origin :  From  the  lateral  surface  of  the  neck  at  the  level  of  the 
sixth  vertebra  and  from  the  transverse  process  of  that  vertebra ;  by 
fibers  from  the  sacro-transverso-transversalis.  It  extends  superficial- 
ly to  its 

Insertion :    On  the  posterior  border  of  the  squamosal. 

Action :    Aids  in  lateral  and  dorsal  movement  of  the  head. 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

Sacro-transverso-transversalis 

Origin :  From  the  sacrum,  from  the  anterior  border  of  the  ilium, 
from  the  transverse  processes  of  vertebrae  three  to  twenty-six,  from 
the  anterior  surfaces  of  the  dorsal  portions  of  all  the  ribs  and  from 
the  dorsal  surfaces  of  the  uncini. 

Insertion:  For  the  most  part,  on  the  transverse  processes  and 
ribs  from  the  axis  to  the  sacrum.  From  the  level  of  the  fourth,  fifth, 
sixth  and  seventh  vertebrae,  four  more  or  less  distinct  slips  arise 
which  insert  on  the  occipital  condyle,  the  axis,  the  atlas  and  the  tip 
of  the  transverse  process  of  the  third  cervical  vertebra. 

Action :    Flexor  of  the  body. 

Obliquus  capitis 

Origin :  This  muscle  is  differentiated  from  the  sacro-transverso- 
transversalis  at  about  the  level  of  the  fourth  vertebra.  It  takes 
origin  from  the  transverse  processes  of  vertebrae  three,  four  and  five. 

Insertion :  On  the  ventral  portion  of  the  posterior  border  of  the 
squamosal  and  on  the  posterior  border  of  the  exoccipital. 

Action :    Aids  in  lateral  movements  of  the  head. 

Rectus  capitis  posticus 

Origin:  From  the  spinous  processes  and  dorsal  surfaces  of  the 
axis  and  atlas. 

Insertion:  On  the  posterior  surfaces  of  the  squamosal  and  oc- 
cipital. 

Action :    Aids  in  lateral  movement  of  the  head. 

Innervation:  All  the  dorsal  axial  muscles  are  supplied  by  the 
rami  dorsales  of  the  spinal  nerves. 

THE  APPENDICULAR  MUSCLES 

Spkenodon  is  a  very  sluggish  creature  and  since  it  is  phylogene- 
tically  so  close  to  the  Amphibia,  its  limb  muscles  present  few  special- 
izations. In  the  forelimb,  the  olecranon  process  is  present  making 
the  direction  of  flexion  fixed ;  in  the  posterior  limb,  however,  there 
is  no  osseous  differentiation  to  fix  the  direction  of  flexion  of  the  crus 
on  the  shank.  The  direction  of  flexion  in  the  hind  limb  is  fixed  only 
by  the  position  of  muscle  insertions,  as  is  the  case  in  the  Urodeles. 
Sphenodon  thus  presents  a  perfect  transitional  stage  between  the 
Urodeles  and  the  more  highly  specialized  reptiles,  birds  and  mam- 
mals which  have  the  direction  of  flexion  between  the  first  and  second 
segments  of  both  limbs  fixed  by  osseous  differentiations. 


MYOLOGY  OP  SPHENODON  21 

This  is  a  very  important  fact  from  the  viewpoint  of  serial  hom- 
ology for,  since  the  f orelimb  has  attained  the  form  characteristically 
presented  in  the  higher,  limbed  vertebrates,  and  the  hind  limb  still 
remains  in  a  rather  generalized  condition,  it  should  be  possible  to 
determine  certainly  whether  the  extensor  groups  of  the  two  limbs 
are  or  are  not  serially  homologous.  This  probability  is  further 
strengthened  by  the  fact  the  hind  limb  is  just  sufficiently  fixed  in 
its  action  to  make  possible  an  irrefutable  numbering  of  the  digits. 

The  sluggish  habits  of  the  creatures  have  not  made  the  develop- 
ment of  a  powerful  extensor  of  the  digits  necessary.  As  a  result, 
the  muscle  of  the  antibrachium  homologous  to  the  dorsalis  antibra- 
chialis  of  Necturus,  m.  extensor  communis  digitorum,  is  in  no  way 
specialized.  The  extensor  communis  of  the  hind  limb  has  progressed 
a  little  way  and  sends  a  tendon  along  the  lateral  surfaces  of  the 
third  and  fourth  digits.  The  flexors  of  both  limbs  are  well  developed, 
as  one  might  expect  since  Spkenodon  is  a  burrowing  animal.  The 
rotators  of  the  femur  are  very  well  developed  to  oppose  the  action 
of  the  powerful  caudal  muscles.  Throughout  the  appendicular  mus- 
culature of  Spkenodon,  there  occur  many  accessory  tendons,  perhaps 
make-shift  adaptations  to  a  changing  environment. 

Both  the  specimens  dissected  had  lost  and  regenerated  the  last 
twelve  or  fourteen  caudal  segments.8  This  regenerated  portion  was 
very  interesting  because  the  regeneration  was  far  from  perfect.  The 
regenerated  portion  showed  no  segmentation  whatever.  Instead  of 
vertebra,  a  hollow  cartilaginous  rod  was  formed  into  which  the 
spinal  cord  did  not  penetrate.  Between  the  last  vertebra  and  the 
regenerated  portion  of  the  first  specimen  studied,  there  was  a  necrotic 
mass  about  the  size  of  a  pea.  The  muscle  fibers  in  the  regenerated 
portion  were  arranged  in  fasciculi  which  ran  its  entire  length.  The 
interstices  were  filled  with  firm  fatty  connective  tissue. 

CLASSIFICATION  OF  THE  LIMB  MUSCLES 

In  classifying  the  limb  muscles,  the  method  devised  by  Bolk  will 
be  used. 

Anterior  Limb 

TruncozonaZ:  dorsal;  m.  serratus  anticus,  m.  levator  scapulae  dor- 
salis superficialis,  m.  levator  scapulae  ventralis  superficialis,  m.  tra- 
pezius, m.  cephaJo-clavicularis ;  ventral;  m.  costo-coracoideus,  m. 


s  Byerly,  T.C.,  Note  on  the  Partial  Regeneration  of  the  Caudal  Region  of 
Spkenodon  punctatum.    Anat.  Record,  Jan.  '25. 


22  IOWA  STUDIES  IN  NATURAL  HISTORY 

costo-sterno-eoraeoideus,  m.  serratus  posterior,  m.  rectus  abdominis 
externus,  m.  rectus  abdominis  internus. 

Trunco-stelepodial:  dorsal;  m.  latissimus  dorsi;  ventral;  m.  pee- 
toralis. 

Zono-stelepodial:  dorsal ;  m.  dorsalis  scapulae,  m.  epieoraeo-humer- 
alis,  m.  scapulo-humeralis  anterior,  m.  scapulo-humeralis  posterior, 
m.  subscapulo-eoraeo-braehialis,  m.  eleido-humeralis ;  ventral;  m. 
coraco-brachialis  brevis,  m.  coraco-brachialis  medius,  m.  coraeo- 
braehialis  longus,  m.  supracoraco-humeralis. 

Zono-zeugopodial:  dorsal;  m.  anconeus  medialis;  ventral;  m. 
coraeo-antibrachialis. 

Stele-zeugopodiaZ:  dorsal;  m.  humero-radialis,  m.  anconeus  later- 
alis, m.  anconeus  brevis,  m.  supinator  longus,  m.  anconeus  quartus ; 
ventral ;  m.  humero-antibrachialis,  m.  pronator  teres. 

Stele-actinopodial:  dorsal;  m.  extensor  carpi  radialis,  m.  extensor 
carpi  ulnaris;  ventral;  m.  flexor  carpi  radialis,  m.  flexor  carpi 
ulnaris. 

Zeugo-phalangopodial:  dorsal;  m.  supinator  brevis;  ventral; 
none. 

Interzeugopodial:  dorsal;  none;  ventral;  m.  pronator  quadratus. 

Stele-phalangopodial:  dorsal;  m.  extensor  communis  digitorum; 
ventral ;  m.  flexor  communis  digitorum. 

Basi-phalangopodial:  dorsal;  mm.  extensor  communis  digitorum 
breves,  m.  extensor  pollicis  brevis ;  ventral ;  mm.  flexores  communis 
digitorum  breves,  mm.  lumbricales,  mm.  adductores  communis,  m. 
flexor  pollicis,  m.  abductor  pollicis,  m.  abductor  digiti  minimi,  op- 
ponens  digiti  minimi. 

Actino-phaZangopodial:  dorsal;  mm.  interossei  dorsales;  ventral; 
mm.  interossei  dorsales. 

Posterior  limb 

Truneo-zonal:  dorsal;  m.  ilio-sacro-transverso-transversalis  and 
m.  caudae  dorsalis  might  be  placed  under  this  head  but  fall  more 
properly  under  the  head  of  dorsal  axial  musculature  because  they 
are  innervated  by  the  dorsal  rami  of  the  spinal  nerves  and  the  dorsal 
rami  never  supply  limb  muscles  in  higher  forms;  ventral;  m.  ilio- 
sacro-costo-costalis  and  m.  ilio-ischio-caudalis  have  already  been  dis- 
cussed under  the  ventral  axial  musculature,  m.  caudi-femoralis,  m. 
caudi-isehio-tibialis,  m.  ischio-caudalis. 

Zono-stelepodial:    dorsal;   m.   ilio-femoralis,   m.   ischio-trochan- 


MYOLOGY  OF  SPHENODON  23 

tericus,  m.  pubo-isehio-femoralis  internus;  ventral;  m.  pubo-ischio- 
trochantericus,  m.  pubo-femoralis,  m.  ischio-femoralis. 

Zono-zeugopodial:  dorsal;  m.  extensor  ilio-tibialis,  m.  ambiens, 
m.  ilio-fibularis ;  ventral ;  m.  pubo-ischio-tibialis,  m.  pubo-tibialis,  m. 
ischio-tibialis  posticus. 

Stele-zeugopodial:  dorsal;  m.  f  emoro-tibialis ;  ventral;  m.  gastroc- 
nemius. 

Stele-phalangopodial:  dorsal;  m.  extensor  communis  digitorum; 
ventral ;  m.  flexor  communis  longus  digitorum. 

Zeugo-basipodial:  dorsal;  m.  tibialis  anticus,  m.  peroneus,  m. 
fibulo-tarsale  4 ;  ventral ;  m.  tibialis  posticus. 

Zeugo-phalangopodial:  dorsal;  m.  abductor  et  extensor  hallucis 
longus. 

IrtierzeugopodM:  m.  pronator  quadratus. 

Bad-phalangopodial:  dorsal ;  mm.  extensores  breves  digitorum,  m. 
abductor  et  extensor  minimi  digiti ;  ventral ;  mm.  lumbricales,  mm. 
adductores  communis,  mm.  flexores  breves  digitorum,  mm.  abduc- 
tores  hallucis  et  secundi. 

INNERVATION  OF  THE  LIMB  MUSCLES 

Designation  of  the  source  of  nerve  supply  for  each  muscle  is  made 
by  indicating  the  number  or  numbers  of  the  spinal  nerves  contribut- 
ing. All  the  foregoing  muscles  designated  as  dorsal  are  supplied  by 
dorsal  branches  of  the  ventral  rami  of  the  spinal  nerves  indicated 
while  those  designated  as  ventral  are  supplied  by  ventral  branches 
of  the  ventral  rami.  The  nerves  are  numbered  consecutively  from 
anterior  to  posterior  in  preference  to  the  application  of  names  taken 
from  human  anatomy. 

Anterior  Limb 
Trunco-zonal — Dorsal 
Serratus  anticus 
This  muscle  consists  of  four  slips  from  the  level  of  vertebrae  six, 
seven,  eight,  and  nine.    Its  slips  take  their 

Origin :  From  the  fascia  overlying  the  ilio-sacro-transverso-trans- 
versalis  at  the  lateral  line  level.  They  extend  dorsad,  overlapping 
somewhat,  to  their 

Insertion :    On  the  dorsal  border  of  the  suprascapula. 
Action:    Adductor  and  levator  of  the  scapula. 
Innervation :    Nn.  spinales  6,  7,  8,  and  9. 


24  IOWA  STUDIES  IN  NATURAL  HISTORY 

COLLI-SCAPULARIS 

This  muscle  occupies  a  similar  position  in.  the  fifth  body  segment. 
It  is  a  levator  of  the  scapula. 

Levator  scapula  dorsalis  superficialis 

Origin:  From  the  anterior  two-thirds  of  the  lateral  surface  it 
runs  cephalad  beneath  the  trapezius  to  converge  with  the  levator 
scapulas  ventralis  superficialis  and  to  its 

Insertion :    On  the  transverse  process  of  the  axis. 

Action :    Levator  of  the  scapula ;  aids  in  lateral  movement  of  head. 

Innervation :    Nn.  spinales  2  and  3. 

Levator  scapula  ventralis  superficialis 

Origin :  From  the  anterior  portion  of  the  mesial  surface  of  the 
scapula  above  the  origin  of  the  trapezius,  it  runs  cephalad  to  its 

Insertion :  By  a  slip  to  the  transverse  process  of  the  axis  and  by 
a  second  slip  on  the  transverse  process  of  the  third  vertebra. 

Action:  Levator  of  the  scapula  and  abductor-adductor  of  the 
head. 

Innervation :    Nn.  spinales  2  and  3. 

Trapezius 

This  muscle  forms  a  broad,  superficial  sheet  which  covers  the  dor- 
sal two-thirds  of  the  side  of  the  neck,  extending  caudad  as  far  as  the 
seventh  vertebra. 

Origin :  From  the  temporal  arch,  dermad  of  the  depressor  man- 
dibulse,  and  from  the  fascia  of  the  dorsal  midline,  its  fibers  converge 
to  their 

Insertion:  On  the  dorsal  third  of  the  anterior  border  of  the 
scapula. 

Action':  It  is  a  protractor  of  the  scapula  and  aids  somewhat  in 
holding  it  in  place. 

Innervation :    Nn.  spinales  2,  3,  and  4. 

Cephalo-clavicularis 

This  muscle  is  analogous  and  probably  homologous  with  the  cleido- 
mastoid  of  higher  forms. 

Origin :  From  the  posterior  border  of  the  dorsal  portion  of  the 
squamosal  beneath  the  depressor  mandibulae.  Its  fibers  extend  ven- 
tro-caudally  to  their 

Insertion :  On  the  anterior  border  of  the  clavicle,  ventral  to  the 
insertion  of  the  trapezius. 


MYOLOGY  OF  SPHENODON  25 

Action :    Levator  of  the  scapula,  abductor-adductor  of  the  head. 
Innervation :    Nn.  spinales  2,  3,  and  4. 

Trunco-stelepodial — Dorsal 
Latissimus  dorsi 

This  muscle  consists  of  a  large,  superficial  fanshaped  sheet.  It 
opposes  the  action  of  the  trapezius,  cephalo-clavicularis  and  cleido- 
humeralis. 

Origin :  From  the  fascia  of  the  dorsal  midline  from  the  level  of 
the  eighth  to  the  level  of  the  fifteenth  vertebrae  its  fibers  extend 
ventro-anteriorly,  its  fibers  converging  toward  their 

Insertion :  It  passes  between  the  scapular  and  coracoid  heads  of 
the  anconeus  medius  to  insert  on  the  postero-dorsal  surface  of  the 
head  of  the  humerus. 

Action :    Abductor  and  retractor  of  the  femur. 

Innervation :    Nn.  spinales  8  to  15. 

Trunco-stelepodial — Ventral 
Pectoralis 

This  muscle  is  a  very  powerful  adductor  of  the  humerus.  Its  an- 
terior portion  draws  the  humerus  forward,  acting  independently, 
while  the  posterior  fibers  draw  the  humerus  backward. 

Origin :  From  the  posterior  border  of  the  episternum  and  the  me- 
dial portion  of  the  clavicle,  from  the  medial  border  of  the  coracoid, 
and  by  digitations  from  the  anterior  fifteen  gastralea. 

Insertion :  On  the  ventral  portion  of  the  head  and  adjacent  prox- 
imal portion  of  the  humerus. 

Innervation :    Nn.  spinales  7  to  10. 

Zono-stelepodial — Dorsal 

DORSALIS  SCAPULA 

Origin :  From  the  lateral  surface  of  the  dorsal  third  of  the  scapula 
its  fibers  converge  ventrally  to  their 

Insertion:  On  the  anterior  surf  ace  of  the  head  of  the  humerus, 
dorsal  to  the  insertion  of  the  cleido-humeralis. 

Action :    Abductor  of  the  humerus. 

Innervation :    N.  spinalis  6. 

Epicoraco-humeralis 
Origin :    From  the  dorsal  (inner)  surface  of  the  coracoid,  it  curves 
posteriorly  around  that  bone  to  its 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

Insertion :  On  the  posterior  surface  of  the  proximal  end  of  the 
humerus. 

Action :    Retractor  of  the  humerus. 
Innervation :    Nn,  spinales  6  and  7. 

SCAPULO-HUMERALIS  ANTERIOR 

Origin:  From  the  lateral  surface  of  the  scapula,  beneath  the 
dorsalis  scapulae. 

Insertion :  On  the  posterior  border  of  the  head  of  the  humerus 
just  lateral  to  the  insertion  of  the  scapulo-humeralis  posterior. 

Action :    Rotator  of  the  humerus. 

Innervation :    Nn.  spinales  7  and  8. 

Scapulo-humeralis  posterior 
Origin :    From  the  posterior  border  of  the  scapula,  its  fibers  ex- 
tend ventrally  to  their 

Insertion :    On  the  posterior  border  of  the  head  of  the  humerus. 
Action :    Rotator  of  the  humerus. 
Innervation :    Nn.  spinales  7  and  8. 

SUBSCAPULO-CORACO-BRACHIALIS 

Origin :  From  the  posterior  two-thirds  of  the  mesial  surface  of 
the  scapula,  it  passes  laterally  between  the  scapula  and  the  first  com- 
plete rib  to  its 

Insertion:  On  the  posterior  border  of  the  proximal  portion  of 
the  humerus,  ventral  to  the  insertions  of  the  scapulo-humeralis  an- 
terior and  posterior. 

Action :    Rotator  of  the  humerus. 

Innervation :    N.  spinalis  8. 

Cleido-humeralis 

Origin:  From  the  posterior  border  of  the  lateral  four-fifths  of 
the  clavicle,  it  extends  posteriorly  to  its 

Insertion:  On  the  anterior  border  of  the  head  of  the  humerus 
and  a  slip  which  gives  rise  to  the  humero-radialis. 

Action :    Protractor  of  the  humerus. 

Innervation :    N.  spinalis  7. 

Zono-stelepodial — Ventral 

CORACO-BRACHIALIS    BREVIS 

This  is  a  very  small  but  distinct  slip  of  the  coraeo-brachialis  which 
lies  between  the  anterior  portion  of  the  pectoralis  and  the  coraeo- 
brachialis  medius.    It  aids  in  adduction  of  the  brachium. 


MYOLOGY  OF  SPHENODON  27 

Origin:  From  the  anterior  portion  of  the  medial  border  of  the 
coraeoid,  it  passes  laterally  to  its 

Insertion:  On  the  ventral  surface  of  the  head  of  the  humerus 
mesiad  from  the  insertion  of  the  pectoralis. 

Innervation :    Nn.  spinales  6  and  7. 

CORACO-BRACHIALIS  MEDIUS 

This  muscle  comprises  the  anterior  portion  of  the  coraco-brachialis 
mass ;  it  is  separated  from  the  coraco-brachialis  longus  by  the  ventral 
nerve  trunk  to  the  antibrachium. 

Origin:  From  the  anterior  half  of  the  ventral  surface  of  the 
coraeoid  it  extends  laterally  to  its 

Insertion :  On  the  ventral  surface  of  the  head  of  the  humerus  and 
the  proximal  portion  of  its  posterior  surface. 

Action :    Adductor  and  retractor  of  the  humerus. 

Innervation :    Nn.  spinales  6  and  7. 

Coraco-brachialis  longus 

This  muscle  comprises  the  posterior  moiety  of  the  coraco-brachialis 
mass.  Together  with  muscle  just  described,  the  coraco-brachialis 
longus  and  the  pectoralis  are  the  chief  mechanical  agencies  used  in 
raising  the  anterior  portion  of  the  body  from  the  ground.  Because 
of  the  poor  adjustment  of  the  limbs  for  walking — they  are  still  truly 
'lateral'  appendages  and  sprawl  badly — this  group  of  muscles  is 
necessarily  very  heavy. 

Origin:  From  the  posterior  half  of  the  ventral  surface  of  the 
coraeoid,  it  extends  laterally  to  its 

Insertion:  Along  the  distal  two-thirds  of  the  posterior  border 
of  the  humerus. 

Innervation :    Nn.  spinales  7  to  10. 

SUPRACORACO-HUMERALIS 

This  muscle  is  continuous  at  its  origin  with  the  coraco-brachialis 
medius  but  separates  from  that  muscle  to  pass  dorsad  to  the  head  of 
the  humerus. 

Origin :  From  the  dorsal  portion  of  the  anterior  border  of  the 
coraeoid,  it  passes  beneath  the  cleido-humeralis  and  dorsal  to  the 
head  of  the  humerus  to  its 

Insertion :  On  the  posterior  border  of  the  proximal  portion  of  the 
humerus,  just  lateral  to  the  insertion  of  the  scapulo-humeralis 
anterior. 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

Action :    Rotator  of  the  humerus. 
Innervation :    N.  spinalis  8. 

Zono-zeugopodial — Dorsal 
Anconeus  medialis 

Origin :  By  a  tendon  from  the  ventro-eaudal  portion  of  the  lateral 
surface  of  the  scapula  and  by  a  second  tendon  from  the  posterior 
border  of  the  coracoid.  These  tendons  unite  and  become  muscular 
just  lateral  to  the  latissimus  dorsi,  which  passes  between  them,  and 
become  muscular.  The  tendon  from  the  scapula  receives  an,  accessory 
tendon  which  passes  to  it  from  the  humerus  beside  the  anterior  bor- 
der of  the  latissimus  dorsi.    Its  fibers  extend  laterally  to  their 

Insertion:  In  common  with  the  other  two  portions  of  the  an- 
coneus group,  on  the  olecranon  process  of  the  ulna. 

Zono-zeugopodial — Ventral 

CORACO-ANTIBRACHIALIS 

Origin :  From  the  third  fourth  posterior  of  the  coracoid,  it  passes 
laterally,  narrowing  to  a  thin  flat  ligament  as  it  passes  the  head  of 
the  humerus,  and  finally  passes  between  the  eoraco-brachialis  longus 
and  the  humero-antibrachialis  to  its 

Insertion :  On  the  proximal  portion  of  the  medial  border  of  the 
radius. 

Action :    Flexor  of  the  antibrachium. 

Innervation :    Nn.  spinales  6,  7,  and  8. 

Stele-zeugopodial — Dorsal 

HUMERO-RADIALIS 

Origin :  From  the  lateral  portion  of  the  eleido-humeralis,  whence 
it  extends  laterally  to  its 

Insertion :  On  the  proximal  portion  of  the  medial  surface  of  the 
radius. 

Action :    It  is  a  flexor  of  the  antibrachium. 

Innervation :    N.  spinalis  7. 

Anconeus  lateralis 

Origin :  From  the  lateral  surface  of  the  head  of  the  humerus, 
just  caudal  to  the  insertions  of  the  eleido-humeralis  and  of  the  dor- 
salis  scapulae,  it  extends  laterally  between  the  humero-radialis  and 
the  anconeus  medialis,  unites  with  the  latter  and  passes  to  its 

Insertion :  On  the  olecranon  process  by  the  aponeurosis  common 
to  the  group. 


MYOLOGY  OF  SPHENODON  29 

Action :    Extensor  of  the  antibrachium. 
Innervation :    Nn.  spinales  7  and  8. 

Anconeus  brevis 

Origin :  Prom  the  posterior  border  of  the  humerus,  beneath  the 
anconeus  medialis.  It  is  a  small  muscle  lying  just  dorsal  to  the 
coraco-brachialis  longus  and  passes  laterally  from  its  origin  to  its 

Insertion:  In  common  with  the  anconeus  medialis  and  the  an- 
coneus lateralis,  on  the  olecranon  process. 

Innervation :    Nn.  spinales  7  and  8. 

Zono-zeugopodial — Ventral 

HUMERO-ANTIBRACHIALIS 

Origin :  From  the  proximal  portion  of  the  antero-ventral  surface 
of  the  humerus  just  distal  to  the  insertion  of  the  pectoralis. 

Insertion :  On  the  proximal  portion  of  the  ventro-mesial  surface 
of  the  radius. 

Action :    Flexor  of  the  antibrachium. 

Innervation :    Nn.  spinales  6,  7,  and  8. 

Pronator  teres 

Origin :  From  the  anterior  surface  of  the  medial  condyle  of  the 
humerus  it  extends  laterally  and  anteriorly  beneath  the  flexor  carpi 
radialis  to  its 

Insertion :  On  the  ventro-mesial  surface  of  the  distal  half  of  the 
radius. 

Action :  Pronator  of  the  antibrachium. 

Innervation :    N.  spinalis  6. 

Stele-actinopodial^-Dorsal 
Extensor  carpi  radialis 

Origin :  From  the  anterior  surface  of  the  outer  condyle  of  the 
humerus  it  extends  along  the  outer  surface  of  the  radius  to  its 

Insertion :  For  the  most  part,  by  muscle  fibers  on  the  outer  sur- 
face of  the  distal  portion  of  the  radius ;  a  slip  inserts  by  tendinous 
fibers  on  carpale  1. 

Action:  Extensor  of  the  carpus  and  adductor  of  the  anti- 
brachium. 

Innervation :    N.  spinalis  7. 

Extensor  carpi  ulnaris 
Origin :   From  the  outer  condyle  of  the  humerus,  just  distal  to  the 
origin  of  the  extensor  communis  digitorum. 


30  IOWA  STUDIES  IN  NATURAL  HISTOEY 

Insertion :    Outer  surface  of  carpale  5. 

Action:    Extensor  of  the  carpus,  abductor  of  the  antibrachium. 

Innervation :    Nn.  spinales  6,  7,  and  8. 

Zeugo-phalangopodial — Dorsal 
Supinator  brevis 
Origin :    From  the  medial  surface  of  the  middle  third  of  the  ulna, 
its  fibers  run  antero-distad  to  their 

Insertion:     On  the  base  of  the  inner  surface  of  the  first  meta- 
carpal. 

Action :    Supinator  of  the  manus. 
Innervation:    N.  spinalis  7. 

Interzeugopodial 
Pronator  quadratus 
Origin :    Prom  the  inner  surface  of  the  distal  two-thirds  of  the 
ulna  its  fibers  traverse  the  space  between  the  radius  and  the  ulna 
to  their 

Insertion :    On  the  inner  surface  of  the  distal  head  of  the  radius. 
Action :    Pronator  of  the  antibrachium. 
Innervation :    Nn.  spinales  6,  7  and  8,  ventral. 

Stele-actinopodial — Ventral 
Flexor  carpi  radialis 
Origin :    From  the  medial  condyle  of  the  humerus,  its  fibers  ex- 
tend distad  and  diagonally  across  the  antibrachium  to  their 

Insertion:    On  the  lateral  surface  of  the  base  of  the  first  meta- 
carpal 

Action :    Flexor  of  the  manus. 
Innervation :    Nn.  spinales  6  and  7. 

Flexor  carpi  ulnaris 
Origin:     From  the  inner  surface  of  the  medial  condyle  of  the 
humerus,  it  extends  along  the  outer  border  of  the  ulna  to  its 
Insertion :    On  the  outer  surface  of  carpale  5. 
Action :    Flexor  of  the  carpus  and  abductor  of  the  manus. 

Stele  phalangopodial — Dorsal 
Extensor  communis  digitorum 
Origin:     From  the  lateral  condyle  of  the  humerus,  it  extends 
superficially  to  its 

Insertion :    Into  the  aponeurosis  covering  the  dorsum  of  the  manus 
and  on  the  dorsal  surfaces  of  the  distal  series  of  carpals. 


MYOLOGY  OF  SPHENODON  31 

Action :    Levator  of  the  maims  and  extensor  of  the  antibrachium. 
Innervation :    Nn.  spinales  7  and  8. 

Plexor  communis  digitorum 

Origin :  1)  By  one  head  from  the  medial  condyle  of  the  humerus ; 
2)  a  second  head  from  the  proximal  half  of  the  ulna;  3)  a  small 
lateral  head  from  the  distal  portion  of  the  ventral  surface  of  the 
ulna. 

Insertion :  This  muscle  broadens  into  a  flat  tendinous  sheet  which 
divides  into  five  tendons  which  are  inserted  into  the  bases  of  the 
ultimate  phalanges  of  each  of  the  digits. 

Action :    Flexor  of  the  phalanges. 

Innervation :    Nn.  spinales  7  and  8. 

Basi-phMangopodial — Dorsal 

EXTENSORES  COMMUNIS  DIGITORUM  BREVES 

a)  Adductor  pollicis  brevis 

Origin :  The  muscles  comprising  the  group  have  a  common  origin 
on  the  distal  portion  of  the  dorsal  surface  of  the  ulna.  The  adductor 
pollicis  brevis  is  the  first  slip  of  the  group. 

Insertion:  On  the  inner  surface  of  the  first  phalanx  of  the  first 
digit. 

b)  Extensor  pollicis  brevis 
This  is  the  second  slip  of  the  group. 

Insertion :    On  the  ultimate  phalanx  of  the  first  digit. 

c)     Extensores  communis  digitorum  breves 

The  slips  to  the  four  remaining  digits  have  been  grouped  under 
this  head  as  no  abductor  minimi  digiti  has  been  differentiated. 

Insertion :    On  the  ultimate  phalanges  of  digits  two  to  five. 

Action :  This  group  of  muscle  slips  furnishes  the  chief  means  for 
extension  of  the  digits. 

Innervation :    N.  spinalis  7. 

Basi-phalangopodial — Ventral 

FLEXORES  COMMUNIS  DIGITORUM 

Origin :  By  a  head  from  the  distal  portion  of  the  ventral  surface 
of  the  ulna  and  by  a  head  from  the  flexor  communis  digitorum. 

Insertion :  This  sheet  is  perforated  near  the  points  of  insertion 
by  the  tendons  of  the  flexor  communis  digitorum  and  thus  has  a 
point  of  insertion  on  both  sides  of  each  of  the  phalanges  of  the  prox- 
imal series. 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

Action :    Flexor  of  the  digits. 
Innervation :    Nn.  spinales  6,  7,  and  8. 

LUMBRICALES 

Origin :  These  muscles,  six  in  number,  take  origin  from  the  ven- 
tral surface  of  the  tendinous  distal  portion  of  the  flexor  communis 
digitorum. 

Insertion :  On  the  lateral  surfaces  of  the  proximal  phalanges  of 
digits  two,  three,  and  four. 

Adductores  communis 

Origin :  From  the  ventral  surface  of  the  ulnare,  this  sheet  extends 
antero-dorsad  to  its 

Insertion :  On  the  ventral  surface  of  the  proximal  phalanges  of 
digits  one,  two,  and  three. 

Action :    Adductor  and  pronator  of  the  manus. 

Innervation :    Nn.  spinales  6,  7,  and  8. 

Flexor  pollicis 
Origin :    Fi*om  the  ventral  surface  of  carpale  1. 
Insertion :    On  the  base  of  the  proximal  phalanx  of  the  first  digit. 

Abductor  pollicis 
Origin :    From  the  ventral  surface  of  the  intermediale. 
Insertion :    On  the  medial  surface  of  the  proximal  phalanx  of  the 
first  digit. 

Action :    Abductor  of  the  pollex. 

Abductor  digiti  minimi 
Origin :    From  the  ventral  surface  of  carpale  4. 
Insertion :    On  the  inner  surface  of  the  proximal  phalanx  of  the 
fifth  digit. 

Opponens  digiti  minimi 
Origin :    From  the  lateral  surface  of  the  ulnar  sesamoid. 
Insertion :    On  the  ventral  surface  of  the  proximal  phalanx  of  the 
fifth  digit. 

Actino-plwlangopodial — Dorsal 
Interossei  dorsales 
Origin :    From  the  bases  of  all  the  metacarpals. 
Insertion :    On  the  dorsal  and  lateral  surfaces  of  the  bases  of  the 
proximal  series  of  phalanges. 


MYOLOGY  OF  SPHENODON  33 

Actino-pfadangvpodial — Ventral 
Interossei  volares 
Origin :   From  the  ventral  surfaces  of  the  bases  of  the  metacarpals. 
Insertion :    On  the  ventral  and  inner  surfaces  of  the  bases  of  the 
proximal  series  of  phalanges. 

Action :  Both  series  of  interossei  act  as  abductors  and  adductors 
of  the  digits. 

Innervation :  All  the  deep  muscles  of  the  hand  are  innervated 
by  nn.  spinales  7  and  8. 

Posterior  Limb 

Trunco-zonal — Ventral 
Caudi-femoralis 

Origin :  From  the  lateral  surfaces  of  the  haemal  spines  of  the 
caudal  vertebrae,  its  fibers  extend  antero-laterally  to  their 

Insertion :  The  fibers  of  this  muscle  converge  and  pass  between 
the  ilium,  the  ischium,  and  the  tendinous  portion  of  the  caudi-isehio- 
tibialis  to  insert  on  the  proximal  portion  of  the  ventral  surface  of 
the  femur.  An  accessory  tendon  arises  on  the  lateral  surface  of  the 
muscle  near  the  point  of  insertion  and  runs  laterally,  parallel  to  the 
femur,  to  insert  on  the  proximal  portion  of  the  medial  surface  of  the 
tibia. 

Action:  This  muscle  serves  a  three-fold  function;  it  is  a  rotator 
of  the  femur,  adductor  of  the  femur  and  an  abductor-adductor  of 
the  tail.  By  means  of  its  accessory  ligament  to  the  tibia,  it  also  aids 
in  tensing  the  leg. 

Innervation :    Nn.  spinales  27  and  caudal. 

Caudi-ischio-tibiaus 

Origin :  From  the  ventral  surfaces  of  the  transverse  processes  of 
the  six  anterior  caudal  vertebrae  and  from  the  tuber  ischium. 

Insertion :  On  the  proximal  portion  of  the  medial  surface  of  the 
tibia. 

Action :    Flexor  of  the  crus  on  the  shank. 

Innervation :    Nn.  spinales  26,  27,  and  caudal. 

ISCHIO-CAUDALIS 

Origin:  From  the  lateral  surfaces  of  the  haemal  spines  of  the 
caudal  vertebrae. 

Insertion :    On  the  tuber  ischium. 

Action :    Depressor  and  abductor-adductor  of  the  caudal  region. 

Innervation :    N.  spinalis  27  and  the  succeeding  caudal  nerves. 


34  IOWA  STUDIES  IN  NATURAL  HISTORY 

Zono-stelepodial — Dorsal 
Ilio-femoralis 
Origin:     From  the  dorsal  portion  of  the  lateral  surface  of  the 
ilium. 

Insertion :    On  the  middle  third  of  the  caudal  surface  of  the  femur. 
Action :    Abductor  and  rotator  of  the  femur. 
Innervation :    N.  spinalis  24. 

ISCHIO-TROCHANTERICUS 

Origin:  From  the  caudal  portion  of  the  inner  surface  of  the 
ischium,  it  curves  around  the  posterior  border  of  the  ischium  and 
then  runs  anteriorly  to  its 

Insertion :    On  the  posterior  surface  of  the  inner  trochanter. 

Action :    Rotator  of  the  thigh. 

Innervation :    Nn.  spinales  25  and  26. 

PUBO-ISCHIO-FEMORALIS  INTERNUS 

Origin :  From  the  inner  surface  of  the  pubis  and  from  the  an- 
terior portion  of  the  inner  surface  of  the  ischium,  this  muscle  curves 
antero-dorsally  around  the  anterior  side  of  the  pubis  just  lateral  to 
the  pubic  tuberosity,  to  its 

Insertion :  On  the  second  proximal  fourth  of  the  dorso-anterior 
surface  of  the  femur,  along  the  anterior  border  of  the  origin  of  the 
femoro-tibialis. 

Action :    Extensor  and  rotator  of  the  femur. 

Innervation :    N.  spinalis  23. 

Zono-stelepodial — Ventral 

PUBO-ISCHIO-TROCHANTERICUS 

Origin:  From  the  entire  ventral  surface  of  the  pubo-ischiadic 
plate  its  fibers  extend  laterally  to  converge  at  their 

Insertion :  On  the  ventral  surface  of  the  inner  trochanter  of  the 
femur. 

Action :    Adductor  of  the  thigh. 

Innervation :  N.  spinalis  24. 

PUBO-FEMORALIS 

Origin :  From  the  inner  surface  of  the  pubis  and  the  lateral  pubic 
tuberosity,  this  muscle  extends  laterally  between  the  femoro-tibialis 
which  lies  dorsal  to  it  and  the  pubo-tibialis  which  lies  ventral  to  it, 
to  its 


MYOLOGY  OF  SPHENODON  35 

Insertion:  On  the  middle  portion  of  the  ventro-eaudal  surface 
of  the  femur. 

Action :    Abductor  and  rotator  of  the  femur. 
Innervation :    N.  spinalis  24. 

ISCHIO-FEMORALIS 

Origin :  From  the  middle  proximal  portion  of  the  dorsal  surface 
of  the  pubo-ischio-tibialis  and  it  extends  into  the  thigh  parallel  to 
that  muscle. 

Insertion :  On  the  ventral  surface  of  the  femur,  lateral  to  the  in- 
sertion of  the  pubo-f  emoralis. 

Action :    Adductor  of  the  thigh. 

Innervation :    Nn.  spinales  26  and  25. 

Zono-zeugopodial — Dorsal 
Extensor  hjo-tibiaus 
Origin :    From  the  dorsal  half  of  the  anterior  border  of  the  ilium. 
Insertion :    On  the  proximal  portion  of  the  anterior  surface  of  the 
tibia. 

Action :    Extensor  of  the  crus. 
Innervation :    N.  spinalis  24. 

Ambiens 

Origin:  By  tendinous  fibers  from  the  lateral  tuberosity  of  the 
pubis. 

Insertion:  On  the  proximal  portion  of  the  anterior  surface  of 
the  tibia. 

Action :    Extensor  of  the  crus. 

Innervation :    N.  spinalis  24. 

Remarks:  The  two  preceding  muscles  have  a  common  insertion 
and  have  been  termed  the  extensor  triceps  femoris. 

Ilio-fibularis 

Origin :  From  the  posterior  border  of  the  ilium,  just  above  the 
level  of  the  acetabulum. 

Insertion:  On  the  lateral  surface  of  the  proximal  end  of  the 
fibula. 

Action :    Flexor  of  the  crus. 

Innervation :    N.  spinalis  25. 

Remarks :  This  muscle  has  been  termed  the  biceps  f  emoralis  by 
Furbringer  and  since  it  is  quite  certainly  supplied  by  the  nerve 
which  is  homologous  with  the  peroneus  communis  of  higher  forms, 


36  IOWA  STUDIES  IN  NATURAL  HISTORY 

this  homology  may  certainly  be  accepted.  If  this  be  true,  however, 
the  ilio-fibularis  can  in  no  case  be  serially  homologous  with  the 
coraco-antibrachialis  of  the  forelimb  which  has  been  termed  the 
biceps  brachii  by  Furbringer. 

Zono-zeugopodial — Ventral 

PUBO-ISCHIO-TIBIALIS 

Origin :  From  the  ventral  surface  of  the  lateral  pubic  tuberosity, 
from  the  ischiadic  and  pubic  symphyses  by  a  thin,  tough,  tendinous 
sheet ;  the  separate  elements  of  this  sheet  converge  and  thicken  into 
a  heavy,  flat  muscle  which  covers  almost  the  entire  ventral  surface 
of  the  thigh. 

Insertion :  On  the  proximal  portion  of  the  ventral  surface  of  the 
tibia. 

Action :    Flexor  of  the  tibia ;  adductor  of  the  entire  leg. 

Innervation :    Nn.  spinales  25  and  26. 

Pubo-tibialis 
Origin :    From  the  lateral  surface  of  the  lateral  pubic  tuberosity. 
Insertion:     On  the  proximal  portion  of  the  inner  aspect  of  the 
tibia. 

Action :    Adductor  and  flexor  of  the  crus. 
Innervation :    N.  spinalis  24. 

ISCHIO-TIBIALIS  POSTICUS 

Origin :    From  the  lateral  tuberosity  of  the  ischium. 
Insertion :    On  the  medial  aspect  of  the  tibia,  just  distal  to  the  in- 
sertion of  the  caudo-ischio-tibialis. 
Action :    Flexor  of  the  crus. 
Innervation :    N.  spinalis  24. 

ISCHIO-TIBIALIS  POSTICUS 

Origin :    From  the  lateral  tuberosity  of  the  ischium. 

Insertion:  On  the  medial  aspect  of  the  tibia,  just  distal  to  the 
insertion  of  the  caudo-ischio-tibialis. 

Action :    Flexor  of  the  crus. 

Innervation :    Nn.  spinales  26  and  27. 

Remarks:  A  slip  arises  from  the  distal  end  of  this  muscle  and 
forms  a  part  of  the  origin  of  the  flexor  communis  digitorum. 

Femoro-tibialis 
Origin :    From  the  middle  third  of  the  dorso-anterior  surface  of 
the  femur. 


MYOLOGY  OF  SPHENODON  37 

Insertion :  On  the  proximal  portion,  of  the  antero-lateral  surface 
of  the  tibia,  in  common  with  the  ambiens  and  the  extensor  ilio- 
tibialis. 

Action :    Extensor  of  the  eras. 

Innervation :    By  the  second  nerve  of  the  lumbar  plexus. 

Stele-phalangopodicrt — Dorsal 
Extensor  communis  digitorum 

Origin :  Prom  the  dorsal  surface  of  the  distal  end  of  the  femur, 
it  extends  superficially  along  the  middle  of  the  dorsal  side  of  the 
crus  to  its 

Insertion:  On  the  inner  surfaces  of  the  bases  of  the  third  and 
fourth  metatarsals ;  each  of  the  two  slips  is  continued  as  a  tendon 
which  runs  along  the  inner  surface  of  the  third  and  fourth  digits 
to  insert  on  their  penultimate  phalanges. 

Action :  Levator  of  the  pes  and  adductor  of  the  third  and  fourth 
digits. 

Innervation:    N.  spinalis  25. 

Stele-phalangopodial — Ventral 
Plexor  communis  longus  digitorum 
Origin:    Prom  the  medio-eaudal  surface  of  the  femur,  from  the 
medial  surface  of  the  fibula,  a  head  from  the  gastrocnemius  and  a 
head  from  the  ischio-tibialis  posticus. 

Insertion :    On  the  ultimate  phalanges  of  each  of  the  digits. 
Action :    Flexor  of  the  digits. 
Innervation:    N.  spinalis  26. 

Stele-zeugopodial — Ventral 
Gastrocnemius 
Origin :    From  the  ventral  surface  of  the  distal  end  of  the  femur, 
from  the  fibula  and  a  head  from  the  ischio-tibialis  posticus. 
Insertion :    Into  the  plantar  aponeurosis. 
Innervation :    N.  spinalis  26. 

Zeugo-hasipodial — Dorsal 
Tibialis  anticus 
Origin:    From  the  proximal  portion  of  the  anterior  surface  of 
the  tibia. 

Insertion:  On  the  lateral  surface  of  the  tibiale,  continued  for- 
ward as  a  tendon  to  the  lateral  surface  of  the  first  digit,  terminating 
on  the  penultimate  phalanx. 


38  IOWA  STUDIES  IN  NATURAL  HISTORY 

Action :    Adductor  of  the  pes  and  of  the  first  digit. 
Innervation :    Nn.  spinales  25  and  26. 

Peroneus 

Origin:  From  the  proximal  portion  of  the  lateral  surface  of- the 
fibula. 

Insertion :  On  the  lateral  surface  of  the  fibulare  and  on  the  lateral 
surface  of  the  penultimate  phalanx  of  the  fifth  digit. 

Action :    Abductor  of  the  pes  and  of  the  fifth  digit. 

Innervation :    N.  spinalis  25. 

FlBULO-TARSALE  4 

Found  in  one  specimen. 

Origin :    Dorsal  surface  of  the  distal  head  of  the  fibula. 

Insertion :    Tarsale  4. 

Action :    Levator  of  the  foot. 

Innervation:    N.  spinalis  25. 

Zeugo-basipodial — Ventral 
Tibialis  posticus 
Origin :    From  the  head  of  the  tibia  and  the  ventral  surface  of 
the  fibula. 

Insertion :  Latero-ventral  surface  of  the  first  phalanx  of  the  hal- 
lux, and  on  the  tibiale. 

Action :    Abductor  of  the  hallux  and  flexor  of  the  pes. 
Innervation :    Nn.  spinales  25  and  26. 

Zeugo-phalangopadM — Dorsal 
Abductor  et  extensor  hallucis  longus 
Origin :    From  the  lateral  surface  of  the  third  distal  fourth  of  the 
fibula. 

Insertion:    1)  Extensor  portion:  On  the  extensor  tendon  of  the 
hallux;  2)  Abductor  of  the  hallux:    On  the  dorso-lateral  surface 
of  the  base  of  the  first  phalanx  of  the  hallux. 
Innervation :    N.  spinalis  25. 

Interzeugapodial 
Pronator  quadratus 
Origin :    From  the  medial  surface  of  the  distal  half  of  the  tibia. 
Insertion:    Slightly  distal  to  the  point  of  origin,  on  the  medial 
surface  of  the  fibula. 

Action :    Rotator  of  the  crus. 
Innervation :    Nn.  spinales  25  and  26. 


MYOLOGY  OF  SPHENODON  39 

Basi-phalangopodial — Dorsal 

EXTENSORES  BREVES  DIGITORUM 

Origin :  The  first  from  the  dorsal  surface  of  the  tibiale,  the  re- 
maining three  from  the  dorsal  surface  of  the  fibulare. 

Insertion :    On  the  extensor  tendons  of  the  first  four  digits. 
Action :    Extensors  of  the  digits. 
Innervation :    N.  spinalis  25. 

Abductor  et  extensor  digiti  minimi 
Origin :    From  the  dorsal  surface  of  the  fibulare. 
Insertion :    On  the  extensor  tendon  of  the  fifth  digit  and  the  dor- 
sal interossei. 
Action :    Abductor  and  extensor  of  the  fifth  digit. 
Innervation :    N.  spinalis  25. 

Basi-phalangopodial — Ventral 

FLEXORES  BREVES  DIGITORUM 

Origin :    From  the  dorsal  surface  of  the  plantar  aponeurosis. 
Insertion :    On  the  bases  of  the  proximal  phalanges. 
Action :    Flexor  of  the  pes. 
Innervation :    N.  spinalis  26. 

LUMBRICALES 

Origin:  From  the  ventral  surface  of  the  distal  portion  of  the 
flexor  communis  digitorum. 

Insertion:  On  the  inner  surfaces  of  the  proximal  phalanges  of 
the  second,  third  and  fourth  digits. 

Action :    Adductor  of  the  second,  third  and  fourth  digits. 

Innervation :    Nn.  spinales  25  and  26. 

Adductores  halluces  et  secundi 

Origin :  From  the  ventral  surface  of  the  fibulare,  beneath  mm. 
adductores  communis. 

Insertion :  On  the  dorsal  and  lateral  surfaces  of  the  penultimate 
phalanges  of  the  first  and  second  digits. 

Action :    Abductors  of  the  first  and  second  digits. 

Innervation :    Third  nerve  of  the  lumbar  plexus. 

Actino-phalangopodial — Dorsal 
Interossei  dorsales 
Origin :    From  the  inner  surfaces  of  the  bases  of  all  the  meta- 
tarsales. 


40  IOWA  STUDIES  IN  NATURAL  HISTORY 

Insertion :  On  the  dorsal  and  lateral  surfaces  of  the  bases  of  the 
proximal  row  of  phalanges. 

Action :    Abductor-adductors  of  the  digits. 
Innervation :    N.  spinalis  25. 

ActinO'phalangopodial — Ventral 
Interossei  plantares 
Origin :    From  the  inner  surfaces  of  the  bases  of  the  second,  third, 
fourth,  and  fifth  metatarsales. 

Insertion:  On  the  outer  surfaces  of  the  penultimate  phalanges 
of  the  first,  second,  third,  and  fourth  digits. 

Opponens  digiti  minimi 

Arises  from  the  inner  surface  of  the  base  of  the  fifth  metatarsal 
and  inserts  on  the  inner  surface  of  the  penultimate  phalanx  of  the 
fifth  digit. 

Innervation :    N.  spinalis  26. 

ANAL  AND  COPULATORY  MUSCLES 

Dne  to  the  fact  that  one  of  the  specimens  dissected  had  a  necrotic 
mass  in  the  wall  of  cloaca,  and  that  the  alimentary  canal  of  the  sec- 
ond had  been  removed  for  another  study,  previous  to  the  dissections 
for  this  paper,  a  thorough  dissection  of  these  muscles  was  impossible. 
Consequently,  no  figures  were  attempted.  The  following  account  by 
Gadow,  taken  from  his  "Remarks  on  the  cloaca  and  on  the  eopula- 
tary  organs  of  the  Amniota,"9  is,  as  far  as  could  be  determined, 
correct.  Unfortunately,  he  made  no  figures  to  show  the  arrangement 
of  the  muscles. 

"Hatteria  possesses  a  m.  perinei  s.  transverso-analis  like  the  Liz- 
ards; also  a  m.  transversus  medianus  almost  exactly  like  that  de- 
scribed in  the  Crocodilia ;  its  most  superficial  fibers  are  transformed 
into  a  distinct  outermost  sphincter,  which,  according  to  the  shape 
of  the  anal  opening,  lies  transversely  and  not  longitudinally  as  in 
the  Crocodilia. 

6 '  From  the  outside  of  the  m.  transversus  medianus,  and  covered  by 
the  m.  sphincter,  starts  on  each  side  a  broad  but  thin  muscle,  which 
runs  back  and  attaches  itself  aponeurotically  on  the  skin  and  on  the 
fascia  of  the  ischio-caudalis,  behind  the  anus.  It  resembles  a  very 
similar  pair  of  muscles  in  the  Lizards. 

"The  odoriferous  glands  get  a  coating  of  striped  muscle  fibers 
from  the  m.  transversus  medianus." 


9  Oadow,  H.,  Phil.  Trans,  of  the  Boy.  Soc,  B  178,  p.  12. 


MYOLOGY  OF  SPHENODON  41 

SEEIAL  HOMOLOGIES 

Serial  homologies  are  based  in  this  paper,  whenever  it  is  possible, 
on  nerve  supply.  In  cases  in  which  the  nerve  supply  was  doubtful 
or  seemed  unconvincing,  an  attempt  was  made  to  correlate  them  with 
the  more  primitive  condition  found  in  Necturus  and  through  such 
a  correlation  to  arrive  at  a  definite  conclusion  regarding  their  serial 
homology. 

Before  any  homology  can  be  attempted,  the  musculature  must  be 
divided  into  visceral  and  parietal  groups  according  to  its  embryonic 
derivation.  The  visceral  musculature  includes  all  the  muscles  de- 
veloped from  the  hypomeres  and  is  confined  to  the  anterior  region 
of  the  body ;  this  includes  the  integumental  musculature  of  Spheno- 
don.  The  parietal  musculature  includes  all  the  axial  and  appen- 
dicular musculature.  Most  of  the  homologies  correspond  to  those 
described  in  previous  work  on  this  and  other  forms  and  in  such  cases 
no  discussion  was  considered  necessary. 

VISCERAL  MUSCULATURE 
This  group  consists  of  the  highly  modified  remnants  of  the  gill 
arch  musculature  of  lower  forms.  In  Sphenodon  it  consists  of  the 
m.  intermandibularis,  m.  sphincter  colli,  m.  sphincter  dorsalis,  m. 
cerato-hyoideus,  m.  stylohyoideus,  m.  mylohyoideus,  m.  temporo- 
massetericus,  m.  pterygoideus  externus,  m.  pterygoideus  internus,  m. 
depressor  mandibular,  m.  constrictor  laryngeus  and  m.  dilator 
laryngeus. 

SERIAL  HOMOLOGUES  IN  THE  VISCERAL  MUSCULATURE 

Derivatives  from  the  mm.  Levatores  arcuum 

Innervation  by 
N.  trigeminus  N.  facialis 

temporo-massetericus  depressor  mandibulae 

pterygoideus  externus  stapedius  (Osawa) 

pterygoideus  internus 

Derivatives  from  the  Depressors 
Innervation  by 
N.  trigeminus  N.  facialis  N.  vagus 

mylohyoideus  intermandibularis  constrictor  laryngeus 

sphincter  colli  dilator  laryngeus 

sphincter  dorsalis 

cerato-hyoideus  stylohyoideus 


42  IOWA  STUDIES  IN  NATURAL  HISTORY 

Judging  from,  its  position  and  relations,  and  by  the  process  of 
elimination,  the  eerato-hyoideus  must  represent  the  anterior  belly 
of  the  digastric  of  higher  forms.  Stretched  as  it  is  between  two 
elements  of  the  hyoid,  and  lying  between  the  pterygoideus  internus 
and  the  hyoglossus,  its  position  is  almost  exactly  that  of  the  anterior 
belly  of  the  digastric.  Then,  too,  the  remaining  muscles  of  the  hyoid 
of  Sphenodon  are  constant  or  fairly  so,  through  the  higher  forms 
while  this  muscle  disappears  entirely.  Its  innervation  is  that  of  the 
mylohyoid  and  the  anterior  intermandibularis  of  lower  forms,  the 
hypothetical  phylogenetic  precursor  of  the  anterior  belly  of  the 
digastric. 

SERIAL  HOMOLOGUES  IN  THE  PARIETAL  MUSCULATURE 

Axial  Musculature 

Innervation  by 

Rami  dorsales  of  nn.  spinales 

semispinalis  capitis  sacro-transverso-transversalis 

interspinals 
cervicis  capitis  caudae  dorsalis 

obliquus  capitis  sacro-transverso-transversalis 

rectus  capitis  posticus 

Rami  ventrales  of  nn.  spinales 
Geniohyoideus,  cleido-episterno-hyoideus,  sterno-coracoideus  profundus,  rectus 
abdominis  externus,  ischio-caudalis   (partim). 

This,  the  most  ventral  series  of  axial  muscles,  is  practically  con- 
tinuous from  the  symphysis  menti  to  the  caudal  extremity.  The 
geniohyoid  is  innervated  by  the  hypoglossal  nerve  but  that  nerve  is 
essentially  a  spinal  nerve  in  function  and  phylogeny.  The  inclusion 
of  the  sterno-coracoideus  profundus  in  this  series  might  be  ques- 
tioned but  since  the  coracoid  and  clavicle  are  movable,  are  moved, 
by  this  muscle,  its  internal  position  should  not  exclude  it  from  the 
series. 

Genioglossus,  hyoglossus,  sterno-coracoideus  superficialis,  rectus  abdominis 
internum. 

This  second  and  deeper  ventral  series  is  not  so  complete  as  the 
more  primitive  superficial  layer;  it  is  broken  in  both  the  cervical 
and  pelvic  regions. 

longus  colli  (partim)  ilio-sacro-costo-costalis         ilio-ischio-caudalis 

longus  colli  (partim)  obliquus  internus  isehio-caudi- tibialis 

triangularis  sterni  transversalis  abdominis 


MYOLOGY  OF  SPHBNODON 


43 


omohyoideus 

costo-coracoideus 

costo-sterno-coracoideus 

abdomino-costales 
intercostales  intend  breves 
intercostales  externi  breves 

trapezius 

latissimus  dorsi  (partim) 

levator  scapulae  superficialis  dorsalis 

cephalo-clavicularis 

serratus  posterior  (superficial  layer) 

colli  scapularis 

serratus  anterior 

levator  scapulae  ventralis  superficialis 

serratus  posterior   (deeper  portion) 

intercostales  ventrales 


intercostales  intend  longi 


obliquus  externus 
obliquua  externus 

uncini-costales  breves 
uncini-costales  longi 

intercostales  externi  longi 
costo-sterno-scapularis 


The  coccygeal  portion  of  the  caudi-isehio-femoralis  and  the  ischio- 
caudalis  (partim)  are  probably  posteriorly  the  serial  homologues  of 
the  above  series,  beginning  with  the  omohyoideus. 

SERIAL  HOMOLOGY  OF  THE  INTRINSIC  MUSCLES 

OP  LIMBS 

Innervation  by  nn.  spinales 


6  and  7 

cleido-humeralis 

latissimus  dorsi  (partim) 
dorsalis  scapulae 
scapulo-humeralis  anterior 
scapulo-humeralis  posterior 

humero-radialis 
supinator  longus 

supracoraco-humeralis 

coraco-brachialis  brevis 
coraco-brachialis  medius 

subscapulo-coraco-humeralis 
epicoraco-humeralis 

6,  7,  8 

anconeus  lateralis 


24  and  25 

Dorsal 

pubo-ischio-femoralis  internus 

ilio-femoralis 


ambiens 

Ventral 

pubo-femoralis 

ischio-femoralis 
pubo-ischio-trochantericus 

ischio-trochantericus. 

25 

ilio-fibularis 


44  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  finding  of  satisfactory  evidence  for  or  against  declaring  the 
extensors  and  flexors  of  the  f  orelimbs  to  be  homologues  of  the  ex- 
tensors and  flexors  of  the  hind  limbs  has  been  difficult  and  has  led 
to  more  or  less  disagreement  among  anatomists.  Thane  gives  the 
following  provisional  homologies  in  the  flexors  of  the  proximal  por- 
tions of  the  limbs  in  man;  biceps  flexor  cubiti  (innervation  by  the 
musculo-cutaneous  nerve,  C.  5  and  6)  with  the  ischiadic  head  of  the 
biceps  cruris,  the  semitendinosus  and  the  semimembranosus  (inner- 
vation by  the  nerve  to  the  hamstrings,  L.  4  &  5,  S.  1,  2,  3.)  ;  the 
humeral  head  of  the  biceps  and  the  brachialis  internus  (innervation 
by  the  musculo-cutaneous)  with  the  femoral  head  of  the  biceps 
cruris  (innervation  by  the  peroneal  nerve,  L.  5,  S.  1,  2).  Now 
Cunningham  has  propounded  the  following  laws  which  he  says  are 
applicable  to  both  fore  and  hind  limbs:  "The  dorsal  and  ventral 
strata  of  muscles  are  always  supplied  by  the  corresponding  dorsal 
and  ventral  branches  of  the  nerves  concerned — of  two  muscles,  that 
nearer  the  head  end  of  the  body  tends  to  be  supplied  by  the  higher 
nerve  and  that  nearer  the  tail  end  of  the  body  by  the  lower  nerve. ' ' 
(Herringham)10 

According  to  these  laws,  Thane's  provisional  homologies  are  im- 
possible; but  Thane  makes  exception  to  them  as  follows:  "Nervous 
supply  is  undoubtedly  the  best  and  most  valuable  guide  to  muscular 
homology,  but  is  however  not  infallible,  since  variations  in  the  nerve 
supply  occur  sometimes  in  man,  and  muscles  which  undoubtedly 
correspond  are  occasionally  supplied  by  different  nerves  in  allied 
animals. ' ni  The  innervation  of  these  flexors  and  extensors,  so  far 
as  can  be  ascertained,  is  constant  throughout  the  limbed  vertebrates 
from  Sphenodon  upwards,  at  least  so  far  as  the  dorsal  or  ventral 
nature  of  their  nerve  supply  is  concerned,  so  Thane's  exception 
would  hardly  seem  to  hold  for  them.  His  first  homology,  that  of 
the  biceps  flexor  cubiti  with  the  three  muscles  of  the  hamstring 
group,  may  be  correct  though  there  would  seem  to  be  room  for  doubt 
because  of  the  comparatively  anterior  innervation  of  the  biceps 
flexor  cubiti.  But  since  it  and  its  proposed  homologues  are  all  inner- 
vated by  ventral  branches,  the  homology  may  be  correct,  the  dis- 
crepancy due  to  an  elimination  of  the  more  posterior  nerve  fibers 
in  an  anterior  shifting  of  the  muscle. 

As  for  the  second  homology,  that  of  the  humeral  head  of  the  biceps 


io  Cunningham,  D.J.,  Textbook  of  Anatomy,  p.  671. 

ii  Quain  's  Elements  of  Anatomy,  Tenth  ed.,  vol.  2,  part  2,  p.  277. 


MYOLOGY  OF  SPHENODON  45 

cubiti  and<  the  brachialis  interims  with  the  femoral  head  of  the  biceps 
cruris,  that  cannot  hold.  Even  in  man,  as  in  the  other  limbed  ver- 
tebrates possessing  these  muscles,  the  femoral  head  of  the  biceps  is 
almost  unique  in  its  customary  innervation  by  the  common  peroneal 
nerve,  being  the  only  muscle  in  the  proximal  portion  of  the  hind  limb 
to  be  regularly  so  supplied.  In  the  anterior  limb,  the  anconeus, 
(triceps)  holds  the  same  unique  position  as  regards  the  musculo- 
spiral  nerve,  with  the  exception  of  a  portion  of  the  brachialis  inter- 
nus  (and  this  far  the  proposed  homology  may  be  correct).  Now 
the  humeral  head  of  the  biceps  cubiti  is  innervated  by  the  musculo- 
cutaneous nerve,  which  is  clearly  a  ventral  nerve,  and  the  femoral 
head  of  the  biceps  by  n.  peroneus  communis,  clearly  a  dorsal  nerve. 
This  dorsal  character  of  the  peroneus  communis  is  exceptionally 
clear  in  Sphenodow,  The  peroneus  communis  is  the  sole  source  of 
nerve  supply  for  the  m.  ilio-fibularis,  which  is  certainly  analogous 
in  position,  insertion  and  function  with  the  femoral  head  of  the 
biceps  cruris  of  higher  forms  and,  since  its  nerve  supply  is  hom- 
ologous with  that  of  the  femoral  head  of  the  biceps  cruris  of  those 
higher  forms,  must  be  homologous  with  that  muscle.  Such  a  special 
homology  has  been  proposed  by  Osawa  and  accepted  by  Gregory 
and  Camp  in  their  papers  on  osteology  and  myology. 

The  n.  peroneus  communis  of  Sphenodon  is  quite  certainly  serial- 
ly homologous  with  the  nerve  of  the  anterior  limb  which  supplies 
the  m.  anconeus  since  both  are  dorsal  branches  and  the  sole  source 
of  nerve  supply  for  the  superficial  muscles  of  the  distal  portions  of 
the  limbs.  For  the  same  reasons,  this  anterior  nerve  must  be  ac- 
cepted as  the  special  homologue  of  the  musculo-spiral  of  higher 
forms.  Would  it  not  then  be  reasonable  to  assume  that,  instead  of 
the  homology  proposed  by  Thane,  the  m.  anconeus  lateralis  and  the 
m.  ilio-fibularis  should  be  serially  homologous? 

anconeus  medius  extensor  ilio-tibialis 

anconeus  brevis  f  emoro-tibialis 

Innervation  by  nn.  spinales 
6,  7,  8  25,  26,  27 

Ventral 
pectoralis  caudi-femoralis 

coraco-antibrachialis  pubo-ischio-tibialis 

humero-antibrachialis  pubo-tibialis 


46 


IOWA  STUDIES  IN  NATURAL  HISTORY 


coraco  brachialis  longus 

flexor  communis  digitorum 

flexor  carpi  radialis 
flexor  earpi  ulnaris 

pronator  teres 
pronator  quadratus 
flexores  breves  digitorum 
adductores  communis 
abductor  pollicis 
interossei  volares 
flexor  pollicis 
apponens  digiti  minimi 
adductor  pollicis 

extensor  carpi  radialis 

extensor  carpi  ulnaris 

supinator  brevis 

extensor  communis  digitorum 

extensor  communis  dig.  breves 
abductor  et  ex.  dig.  min. 

fibulo-tarsale  4 

interossei  dorsales 


ischio-tibialis  posticus 
caudi-isehio-tibialis 

flexor  communis  dig.  longus. 

gastrocnemius 

tibialis  posticus   (partim) 

tibialis  posticus   (partim) 

pronator  quadratus 

flexores  breves  digitorum 

adductores  communis 

abductores  communis 

interossei  plantares 

tibialis  posticus  (distal  portion) 

flexores  breves  dig.  (partim) 
Dorsal 

tibialis  anticus 

peroneus 

abductor  et  extensor  hal.   long. 

extensor  communis  digitorum  longus 

extensor  pollicis  brevis 
ex.  com.  dig.  breves. 

interossei  dorsales 


DISCUSSION  AND  COMPARISON 

While  the  musculature  of  Sphenodon  is  still  very  primitive  in 
its  nature,  it  shows  some  marked  advances  from  the  condition  in 
the  more  primitive  Urodeles.  In  discussing  the  advances  found  in 
the  musculature  of  Sphenodon,  the  very  excellent  work  of  H.  H. 
Wilder  on  the  muscles  of  Necturus  is  used  as  a  basis.  Necturus 
presents  the  most  primitive  condition  found  in  any  of  our  living 
and  familiar  limbed  vertebrates. 

A  brief  survey  would  show  a  few  major  changes.  Functional 
gills  do  not  appear  in  Sphenodon  and  this  fact  with  the  elongation 
of  the  cervical  region  (it  is  longer  by  three  segments)  make  a  marked 
change  in  the  musculature  of  that  region.  The  greatest  specializa- 
tion in  the  muscular  system  of  Sphenodon  is  shown  in  the  axial 


MYOLOGY  OF  SPHENODON  47 

musculature  and  that  of  the  distal  portions  of  the  limbs  with  the 
caudal  musculature  shows  the  least. 

In  making  the  special  homologies  necessary  to  such  a  comparison, 
the  following  points  brought  out  by  previous  workers  have  been 
carefully  heeded:  that  vertebrate  parietal  muscles  are  primarily 
divided  into  a  group  above  the  lateral  line  and  a  group  or  mass  be- 
low the  lateral  line;  that  the  limb  muscles  come  from  this  ventral 
mass  and  that  they  too,  are  divided  into  a  dorsal  and  a  ventral  mass; 
that  the  nerve  supply  is  constant  and  split  in  the  same  way  as  the 
primary  muscle  masses;  that  these  primary  muscle  masses  may  split 
longitudinally,  transversely  or  horizontally  to  meet  the  needs  of 
the  stresses  of  varying  habitat  conditions  that  are  important  enough 
to  make  such  splitting  a  survival  character;  that  the  units  so  pro- 
duced may  later  fuse  or  disappear  or  shift  their  origins  or  inser- 
tions or  both  but  that  they  seldom  or  never  shift  their  nerve  supply. 

In  the  visceral  musculature,  there  has  been  a  considerable  amount 
of  shifting  and  restriction,  due  to  the  loss  of  the  functional  gills. 
The  loss  of  the  levatores  arcuum  and  a  corresponding  spread  of  the 
posterior  intermandibular,  present  the  most  striking  superficial 
changes.  The  depressors  of  the  most  posterior  gill  arch  have  shifted 
to  form  the  intrinsic  muscles  of  the  larynx  and  the  anterior  inter- 
mandibularis  has  given  rise  to  the  mylohyoideus  and  the  coraco- 
hyoideus. 

The  disappearance  of  the  gills  has  also  led  to  a  readjustment  of 
the  superficial  axial  muscles  of  the  neck.  The  omohyoideus  has 
shifted  its  insertion  ventrally  with  the  development  of  the  hyoid 
apparatus.  The  trapezius  has  spread  dorsally  to  the  midline  and 
anteriorly  to  the  head ;  the  cephaJo-clavicularis  is  probably  a  product 
of  the  splitting  of  the  trapezius.  There  have  also  been  marked 
changes  in  the  remainder  of  the  axial  musculature.  The  dorsal 
portion,  which  is  without  differentiation  in  Necturus,  is  split,  except 
in  the  caudal  region,  into  rather  definite  medial  and  lateral  por- 
tions. Each  of  these  longitudinal  divisions  has  undergone  a  con- 
siderable amount  of  specialization  which  has  been  described  in  the 
body  of  this  paper.  The  ventral  axial  musculature,  which  is  also 
very  simple  in  Nectwrus,  has  broken  into  a  complex  system  of  muscles 
for  respiration  and  perhaps  for  crawling. 

Proximal  Portions  of  the  Limbs 
^j  Anterior 

Very  few  significant  changes  from  the  primitive  condition  have 


48  IOWA  STUDIES  IN  NATURAL  HISTORY 

taken  place  in  this  region.  The  procoraco-humeralis  has  disappeared 
or  is  present  as  the  supracoraco-humeralis.  An  epicoraco-humeralis 
has  developed  from  the  ventral  muscle  mass  and  the  brachio-radialis 
has  split  to  form  the  humero-radialis  and  the  supinator  longus  of 
Sphenodow.  The  coraeo-brachialii  have  spread  their  origin  to  cover 
the  entire  ventral  surface  of  the  coracoid  plate. 

Posterior 
The  changes  from  the  urodele  condition  shown  in  this  region  are 
not  extensive.  The  pubo-ischio-tibialis  has  spread  over  the  more  an- 
terior pubo-ischio-femoralis  externus  which  in  turn  has  split  into 
the  ischio-femoralis  and  the  pubo-ischio-trochantericus.  The  pubo- 
tibialis  has  given  rise  to  a  m.  pubo-femoralis  and  the  pubo-ischio- 
femoralis  to  an  ambiens.  The  rectus  abdominis  externus  has  ex- 
tended posteriorly  to  the  caudal  border  of  the  ischiadic  plate.  There 
has  been  a  great  increase  in  the  extent  but  not  in  the  number  of  the 
caudal  muscles.  The  caudali-pubo-ischio-tibialis  has  split  to  form  an 
ischio-tibialis  posticus  and  the  caudo-ischio-tibialis. 

Distal  Portions  of  the  Limbs 
Anterior 
The  dorsum  of  the  antibrachium  is  quite  like  that  of  Nectwrus. 
There  is,  of  course,  an  additional  interosseous  muscle  and  an  addi- 
tional short  extensor  for  the  first  digit  that  which  is  not  present  in 
Nectwrus.  The  only  other  changes  are  a  shift  of  the  origin  of  the 
supinator  to  the  medial  surface  of  the  ulna  and  the  formation  of  an 
aponeurotic  insertion  for  the  extensor  communis  digitorum.  The 
ventral  surfaces  show  a  single  long  flexor  which  inserts  by  tendons 
on  the  ultimate  phalanges  instead  of  into  a  palmar  aponeurosis.  A 
pronator  teres  appears,  probably  split  from  the  flexor  carpi  radialis. 
The  four  layers  of  so-called  flexors  intrinsic  to  the  foot12  are  still 
present.  The  only  important  changes  they  have  made  is  that  the 
flexor  medius  layer  takes  origin  from  the  ventral  surface  of  the  long 
flexor  tendon  as  the  lumbricales,  six  in  number,  and  the  flexor  pro- 
fundus group  is  limited  in  its  action  to  the  three  inner  digits.  Be- 
sides the  typical  fourth  layer  of  interossei  volares,  there  have  split 
from  the  superficial  flexor  group  an  opponens  digiti  minimi,  an  ab- 
ductor digiti  minimi,  an  abductor  pollicis  and  a  flexor  pollicis. 


12  MeMurrich,  J.P.,  Am.  Journ.  of  Anat.,  vol.  6,  p.  471. 


MYOLOGY  OF  SPHENODON  49 

Posterior 
In  the  dorsum  of  the  distal  portion  of  the  hind  limb,  the  only  note- 
worthy advances  are  the  restriction  of  the  insertion  of  the  extensor 
communis  digitorum  to  the  third  and  fourth  digits  and  the  develop- 
ment of  the  abductor  et  extensor  hallucis  longus.  Of  the  muscles 
in  the  ventral  surface  in  this  region,  there  is  little  to  say.  The  long 
flexors  have  increased  somewhat  in  extent  and  number  of  points  of 
origin.  The  layers  in  the  foot  are  quite  like  those  in  the  hand  except 
that  there  are  only  three  lumbricales  and  that  the  third  layer  has 
split  to  form  the  adductores  communis  and  abductores  communis. 
Then,  too,  the  opponens  minimi  digiti,  abductor  minimi  digit!  and 
abductor  pollicis  have  no  homologues,  as  separate  entities  in  the 
foot.  The  flexor  hallucis13  is  a  direct  continuation  of  the  tibialis 
posticus. 

SUMMARY 

1.  Description  of  muscles:  origin,  insertion,  action,  and  inner- 
vation have  been  given  in  tabular  form  for  the  sake  of  brevity ;  the 
figures  are  sufficient  to  illustrate  the  relations. 

2.  A  distinct  m.  triangularis  sterni  was  found;  such  a  muscle 
has  not  previously  been  described  in  any  animal  lower  than  the  class 
Aves. 

3.  The  ventral  axial  musculature  which  has  not  previously  been 
completely  described  or  fully  figured,  has  been  completely  discussed 
and  illustrated. 

4.  Serial  homologies  have  been  made  on  a  basis  of  innervation. 
An  argument  from  facts  brought  to  light  by  dissection  and  based  on 
the  most  widely  accepted  laws  for  serial  homology  has  been  presented 
to  prove  the  homology  of  the  femoral  head  of  the  biceps  cruris  with 
the  anconeus  lateralis. 

5.  Diagrams  of  the  complete  innervation  of  both  limbs  have  been 
included  for  greater  clearness  in  the  comparisons. 

6.  Special  homologies  of  the  muscles  of  Necturus  with  those  of 
Sphenodon,  with  comparisons,  have  been  made. 

13  Osawa,  G.,  Archiv.  fur  Mikros.  Anat.,  Bd.  51. 


BIBLIOGRAPHY 

Bardeen,  C.R.,  The  Nerves  and  Muscles  of  the  Leg.    Am.  Journ.  of  Anat.,  vol. 

6,  '06. 
Byerly,  T.C.,  Note  on  the  partial  regeneration  of  the  caudal  region  in  Spheno- 

don  punctatum.    Anat.  Record,  vol.  30,  '25. 
Cope,  E.D.,  Origin  of  the  Fittest.    Appleton  and  Co.,  N.Y.  '87,  p.  234. 
Cunningham,  D.J.?  Textbook  of  Anatomy,   '06,  p.  671. 

Ecker,  A.,  Anatomy  of  the  Frog.     Trans,  by  G.  Haslam,  Oxford,  '89,  p.  182. 
Gadow,   H.,  Remarks   on  the  Cloaca  and  on  the  Copulatory  Organs   of  the 

Amniota.  Phil.  Trans,  of  the  Roy.  Soc,  B  178,  '87.  p.  12. 
Idem.  Beitrage  zur  Morphologie  der  hinteren  Extremitat  der  Reptilien.   Morph. 

Jahrbuch,  vol.  7,  '82. 
Gegenbaur,  C,  Lehrbuch  der  Anatomic  der  Menschen,  Leipzig,  '96,  Bd.  lf  pp. 

183  and  256. 
Gregory  and  Camp.  Studies  in  Osteology  and  Myology.    Bui.  of  the  Am.  Mus. 

of  Nat.  Hist.,  vol.  38,  '17,  p.  437  et  seq. 
Gunther,    A.,    Contribution    to    the    Anatomy    of    Hatteria    (Bhyncocephalus 

Owen).  Phil.  Trans,  of  the  Roy.  Soc.  157,  '67,  p.  595  et  seq. 
McMurrich,    J.P.,    Phylogeny   of   the   Plantar   Musculature.     Am.    Journ.    of 

Anat.,  vol.  6,  '06. 
Osawa,  G.,  Beitrage  zur  Anatomie  der  Hatteria  punctata.    Archiv.  fur  Mikros. 

Anat.,  Bd.  51,    '98. 
Sobotta,  J.,  Atlas  and  Textbook  of  Anatomy,  ed.  by  McMurrich.    Saunders  Co., 

'09,  p.  212. 
Thane,  G.D.,  Quain's  "Elements  of  Anatomy.''     Vol.  2,  part  2.     Tenth  ed., 

London,  '92,  p.  277. 
Wiedersheim^  R.,  Comparative  Anatomy  of  Vertebrates,  trans,  by  W.N.  Parker, 

Macmillan,   '97,  pp.  128  and  140. 
Wilder,  H.H.,  History  of  the  Human  Body.     Holt  &  Co.,  N.Y.,   '09,  pp.  189 

et  seq. 


50 


EXPLANATION  OF  FIGURES 

1.  Superficial  muscles  of  the  lateral  aspect 

2.  Integumental  muscles 

3.  Musculature  of  the  dorsal  aspect  of  the  posterior  limb 

4.  Ventral  aspect  of  the  anterior  half  of  the  body 

5.  Middle  layer  of  the  ventral  muscles  of  the  forelimb 

6.  Lateral  aspect  of  the  intercostal  musculature 

7.  Medial  aspect  of  the  intercostal  musculature 

8.  Ventro-internal  aspect  of  the  ventral  axial  muscles 

9.  Lateral  aspect  of  the  deeper  muscles  of  the  anterior  region 

10.  Ventral  aspect  of  the  deeper  muscles  of  the  hyoid 

11.  Ventral  aspect  of  the  deep  palmar  muscles 

12.  Laryngeal  muscles 

13.  Ventral  aspect  of  the  caudal  half  of  the  body 

14.  Ventral  aspect  of  the  deep  muscles  of  the  posterior  limb 

15.  Fif th  layer  of  muscles  of  the  plantar  aspect  of  the  foot 

16.  Sixth  layer  of  muscles  of  the  plantar  aspect  of  the  foot 

17.  Seventh  layer  of  muscles  of  the  plantar  aspect 

NOMENCLATURE 

A.  m.  ambiens.  A.O.  m.  adductores  communis.  ACo.  mm.  abdomino-costales. 
ABM.  m.  abductor  pollicis.  AEDM.  m.  abductor  et  extensor  digiti  minimi. 
AL.  m.  anconeus  lateralis.  AM.  m.  anconeus  medius.  AP.  m.  adductor  digiti 
minimi.  APB.  m.  adductor  pollicis  brevis.  CA.  m.  coraco-antibrachialis. 
CBBr.  m.  coraco-brachialis  brevis.  CBL.  m.  coraco-brachialis  longus.  CBM. 
m.  coraco-brachialis  medius.  CC.  m.  costo-coracoideus.  CD.  m.  caudse  dorsalis. 
CEH.  m.  cleido-episterno-hyoideus.  CF.  m.  caudi-femoralis.  CH.  m.  cleido- 
humeralis.  CHy.  m.  cerato-hyoideus.  CL.  m.  constrictor  laryngeus.  CS.  m. 
colli-scapularis.  CSC.  m.  costo-sterno-coracoideus.  DL.  m.  dilator  laryngeus. 
DM.  m.  depressor  mandibulae.  DS.  m.  dorsalis  scapulae.  ECD.  m.  extensor 
communis  digitorum.  EODB.  m.  extensor  communis  digitorum  brevis.  ECDL. 
m.  extensor  communis  digitorum  longus.  ECR.  m.  extensor  carpi  radialis. 
ECU",  m.  extensor  carpi  ulnaris.  EH.  m.  epicoraco-humeralis.  EIT.  m.  ex- 
tensor ilio-tibialis.  FCDB.  m.  flexor  communis  digitorum  brevis.  FCDL.  m. 
flexor  communis  digitorum  longus  (pedis).  FCDS.  m.  flexor  communis  dig- 
itorum. FCR.  m.  flexor  carpi  radialis.  FCU.  m.  flexor  carpi  ulnaris.  FM.  m. 
fibulo-tarsale  4.  FP.  m.  opponens  digiti  minimi.  FT.  m.  femoro-tibialis. 
G.  m.  gastrocnemius.  GO.  m.  genioglossus.  GH.  m.  geniohyoideus.  HA.  m. 
humero-antibrachialis.  HG.  m.  hyoglossus.  HR.  m.  humero-radialis.  IC.  m. 
ischio-caudalis.  ICT.  m.  ischio-caudi-tibialis.  IEB.  mm.  intercostales  extend 
breves.  IEL.  mm.  intercostales  externi  longi.  IF.  m.  ilio-femoralis.  IFi.  m. 
ilio-fibularis.  II.  mm.  intercostales  interni  breves.  IIL.  mm.  intercostales 
interni  longi.  INT.  m.  intermandibularis.  IPL.  mm.  interossei  plantares. 
ISCC.  m.  ilio-sacro-costo-costalis.  1ST.  m.  ilio-ischio-caudalis.  ITP.  m.  ischio- 
tibialis  posticus.  IV.  mm.  intercostales  ventrales.  IVo.  mm.  interossei  volares. 
L.  mm.  lumbricales.  LC.  m.  longus  colli.  LSDS.  M.  levator  scapulae  dorsalis 
superficialis.  LSVS.  m.  levator  scapulae  ventralis  superficialis.  M.  m.  mylohy- 
oideus.  OC.  m.  obliquus  capitis.  ODM.  m.  flexor  pollicis.  OE.  m.  obliquus  ex- 
ternus.  OH.  m.  omohyoideus.  01.  m.  obliquus  internus.  P.  m.  pectoralis.  Pe.  m. 
peroneus.  PF.  m.  pubo-femoralis.  PI.  m.  pterygoideus  internus.  PIT.  m. 
pubo-ischio-tibialis.  PT.  m.  pubo-tibialis.  PITr.  m.  pubo-ischio-trochantericus. 
PT.  m.  pronator  teres.  RAI.  m.  rectus  abdominis  internus.  RAE.  m.  rectus 
abdominis  externus.  RCP.  m.  rectus  capitis  posticus.  S.  m.  supinator  longus. 
SB.  m.  supinator  brevis.  SO.  m.  spinalis  capitis.  SeC.  m.  semispinalis  capitis. 
SCP.  m.  sterno-eoracoideus  profundus.  SCS.  m.  sterno-coracoideus  superficialis. 
SH.  m.  stylohyoideus.  SHa.  m.  scapulo-humeralis  anterior.  SP.  m.  scapulo- 
humeralis  posterior.  STT.  m.  sacro-transverso-transversalis.  TA.  m.  tibialis 
anticus.  TM.  m.  temporo-massetericus.  TP.  m.  tibialis  posticus.  TrA.  m. 
transversalis  abdominis.  TS.  m.  triangularis  sterni.  TTCB.  mm.  uncino-costales 
breves.    UCL.  mm.  uncino-costales  longi. 


PLATES 


PLATE  I 


PLATE 


II 


PLATE  III 


i    0F 


PLATE  IV 


RAI 


'of' 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  "Wickham,  Editor 


VOLUME  XI  NUMBER  7 


ECHINODERMS  AND  INSECTS 
FROM  THE  ANTILLES 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY 


CONTENTS 


A  New  West  Indian  Cidarid  Th.  Mortensen 

Report  on  the  Holothurians  Collected  by  the 
Barbados-Antigua  Expedition  of  the 
University  of  Iowa  in  1918  Elisabeth  Deichmann 

Lepidoptera  Collected  by  the  Barbados-Antigua 
Expedition  from  the  University 
of  Iowa  in  1918  A.  W.  Lindsey 


A  NEW  WEST  INDIAN  CIDARID 

Dr.  Th.  Mortensen 

Zoological  Museum,  Copenhagen 

In  his  "Report  on  the  Crinoidea  and  Echinoidea  collected  by  the 
Bahama  Expedition  from  the  University  of  Iowa  in  1893' '  (Univ. 
of  Iowa  Monogr.,  1,  Ser.  No.  15,  Bull.  Laborat.  Nat.  Hist.,  VII,  p. 
21)  H.  L.  Clark  mentions  a  specimen  of  Histocidaris  sharreri  taken 
"on  the  Pentacrinus  ground  off  Havana.' '  The  specimen  was  not 
submitted  to  him  for  examination,  only  the  photograph  represented 
in  Plate  IV,  fig.  1  of  the  said  report,  and  the  identification  as 
Histocidaris  sharreri  is  not  due  to  him,  having  been  made  years  ago 
in  Washington,  (probably  by  Rathbun).  It  did  not  fail  to  strike 
the  attention  of  Clark  that  the  specimen  looked  somewhat  different 
from  the  typical  sharreri;  still  he  did  not  object  to  the  identification 
as  Histocidaris  sharreri. 

When  making  a  closer  study  of  the  various  species  of  Histocidaris 
for  a  Monograph  of  the  Echinoidea  under  preparation  I  was  struck 
by  the  very  different  aspect  of  the  said  specimen  from  the  type  of 
Histocidaris  sharreri,  as  figured  by  A.  Agassiz  in  the  " Blake' ' 
Echini,  Plate  III,  and  could  not  help  suggesting  that  it  must  be 
another  species  than  sharreri.  I  then  applied  to  Professor  Nutting 
requesting  him  to  do  me  the  service  of  sending  me  some  spines  and 
pedicellariae  of  the  specimen.  At  the  same  time  I  asked  my  friend 
Professor  H.  L.  Clark  to  send  me  a  few  spines  and  pedicellariae  of 
the  typical  H.  sharreri,  these  having  never  been  figured  or  described. 
Both  Professor  Nutting  and  H.  L.  Clark  kindly  complied  with  my 
wish,  and  I  was  thus  able  to  make  a  direct  comparison  of  the  oral 
primaries  and  the  pedicellariae  of  the  two  specimens,  and  the  result 
was  that  there  proved  to  be  so  striking  a  difference  in  the  shape  of 
these  structures,  so  very  important  from  a  classificatory  point  of 
view,  that  it  was  beyond  doubt  that  they  must  represent  two  distinct 
species.  Having  reached  this  result  I  once  more  applied  to  Professor 
Nutting  requesting  him  to  supply  me  with  information  about  the 
more  important  characters  of  the  test  of  this  specimen,  which  he 
very  kindly  did ;  moreover,  he  supplied  me  with  a  pair  of  fine  photo- 
graphs of  the  specimen.    The  additional  information  was  decidedly 

5 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

confirmatory  of  the  result  obtained  from  the  study  of  the  spines 
and  pedicellariae,  and  it  must  be  regarded  as  an  established  fact  that 
this!  specimen  represents  a  new  species  of  the  genus  Histocidaris, 
the  second  species  of  this  genus  recorded  from  the  West  Indies.  The 
genus  Histocidaris  being  very  richly  represented  in  the  Pacific  ( — I 
have  several  new  species  from  there — )  its  poor  representation  in 
the  West  Indian  seas,  Histocidaris  sharreri  being  the  only  species 
hitherto  known  from  there,  is  rather  strange,  and  there  is  some 
satisfaction  in  the  fact  that  a  second,  very  well  characterized  species 
has  now  been  proved  to  exist  there.  This  also  makes  it  reasonable 
to  expect  that  still  more  interesting  finds  are  awaiting  us  in  those 
wonderfully  rich  West  Indian  seas. 

The  new  species  of  which  I  shall  here  give  a  preliminary  descrip- 
tion accompanied  by  the  photographs  ( — the  full  record  to  appear 
in  the  Monograph  under  preparation — )  I  take  the  pleasure  of 
dedicating  to  Professor  Nutting,  naming  it 

Histocidaris  nuttingi  n.  sp. 

The  specimen  measures  60  mm.  in  horizontal  diameter,  nearly  50  mm.  in 
height,  apical  system  28  mm.  in  diameter;  the  longest  spine  is  155  mm.  long, 
thus  2.5  times  the  horizontal  diameter.  The  ambulacra  have  the  interporiferous 
area  covered  with  numerous  small  spines,  leaving  no  bare  median  area;  this 
also  holds  good  for  the  median  interambulacral  area.  9  interambulacral  plates 
in  a  series.  The  ocular  plates  appear  to  be  all  in  contact  with  the  periproct, 
the  two  adjoining  the  madreporite  only  narrowly,  the  others  broadly  so.  G-enital 
pores  very  large,  wholly  inside  the  genital  plates. 

The  primary  spines  are  cylindrical,  some  of  them  slightly  flaring  and  fluted 
at  the  tip.  The  surface  of  the  shaft  is  smooth,  with  about  10  not  very  prom- 
inent longitudinal  ridges,  and  some  of  them  with  sparsely  distributed  sharp, 
thorny  spinelets.  The  collar  is  about  4  mm.  long,  distinctly  thicker  in  the 
lower  part.  The  oral  primaries  (three)  are  curved,  elongate,  slender,  with  very 
conspicuous  serrations  in  the  lower  part,  ending  in  a  rather  long  non-serrate 
point  (figs.  1-2).  The  secondary  spines  (fig.  4)  are  8-9  mm.  long,  gently  tap- 
ering to  a  rounded  point;  they  are  markedly  concave  in  their  whole  length. 
The  ambulacral  spines  are  of  the  same  length,  but,  as  usual,  much  more 
slender,  scarcely  flattened.  The  pedicellarice  are  very  slender,  the  valves  nar- 
row, without  any  deepening  in  the  blade  above  the  apophysis  (fig.  6).  They 
reach  a  length  of  head  of  about  4  mm. ;  smaller  samples  do  not  differ  in  struc- 
ture from  the  larger  ones.  It  is  a  curious  fact  that  the  valves  are  often  of 
unequal  length  (fig.  9)  ;  this  may  not  improbably  be  due  to  their  having 
broken  off  the  point  and  then  regenerated,  though  not  to  the  original  length. 
Color  of  both  primary  and  secondary  spines  white,  the  collar  only  with  a 
slightly  darker  tint. 

Occurrence:    Found  on  the  "Pentaerinus  ground' '  off  Havana, 


NEW  WEST  INDIAN  CIDARID  7 

Mbrro  Castle  bearing  S.  W.  by  W.  about  two  and  one-half  miles; 
140  fathoms. 

From  Histocidaris  sharreri  the  new  species  differs  markedly  in 
the  shape  of  the  spines  and  pedieellariae.  In  H.  sharreri  the  primary 
spines  have  numerous  fine  longitudinal  ridges,  finely  and  densely 
serrate;  the  oral  primaries  are  short  and  broad,  nearly  spatulate, 
very  different  from  the  elegant,  slender  oral  primaries  of  H.  nuttin- 
gi  (fig.  3).  The  ambital  primaries  are  scarcely  more  than  twice  the 
horizontal  diameter.  The  secondary  spines  are  only  slightly  ex- 
cavated in  the  middle  and  distinctly  thickened  at  the  end  (fig.  5) . 

The  pedieellariae  of  the  large  form  (fig.  10)  have  a  broad,  conical 
head;  the  blade  is  elongate-triangular,  with  sides  somewhat  re- 
enteringly  curved,  and  with  a  conspicuous  depression  above  the 
epiphysis  (fig.  7).  There  is  a  small  form  of  pedicellaria  with  nar- 
row, slender  valves  (fig.  8),  quite  different  from  the  larger  form. 

A  good  deal  of  confusion  has  been  reigning  with  regard  to  Histo- 
cidaris sharreri,  not  only  the  new  species  here  described,  but  also 
several  other  species  having  been  confused  with  it.  This  was 
especially  the  case  with  Calocidaris  micans  (Mrtsn.),  and  I  would 
take  the  opportunity  here  of  calling  attention  to  the  fact  that  the 
Plate  IV,  figs.  1-2  of  the  "Blake"  Echini,  the  only  detail  figures  of 
"Porocidaris  sharreri"  ever  published,  are  really  of  Calocidaris 
micans — as  H.  L.  Clark  on  my  suggestion  has  confirmed  in  a  letter 
to  me.  Thus  the  only  figure  really  representing  Histocidaris  sharreri 
is  that  on  Plate  III  of  the  "Blake"  Echini,  which  represents  the 
type  specimen  of  that  species. 

I  beg  to  express  my  sincerest  thanks  to  Professor  C.  C.  Nutting 
and  H.  L.  Clark  for  their  kindness  in  supplying  me  with  the  neces- 
sary information  and  preparations,  enabling  me  to  establish  the 
characters  of  the  new  species  as  well  as  of  that  rather  ill-treated 
species,  Histocidaris  sharreri. 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

EXPLANATION  OF  FIGURES 

Figs.  1-2.  Oral  primary  spine  of  Eistoddaris  nuttingi,  in  front  view  (1)  and 

side  view  (2).  X  2.45 
Fig.    3.  Oral  primary  spine  of  E.  sharreri;  front  view.  X  2.45 
Fig.    4.  Secondary  spine  of  E.  nuttingi.  X  12 
Fig.     5.  Secondary  spine  of  E.  sharreri.  X  12 
Fig.    6.  Valve  of  large  tridentate  pedieellaria  of  E.  nuttingi.  X  27 
Fig.     7.  Valve  of  large  tridentate  pedieellaria  of  E.  sharreri.  X  27 
Fig.     8.  Valve  of  small  tridentate  pedieellaria  of  JET.  sharreri.  X  27 
Fig.     9.  Large  tridentate  pedieellaria  of  E.  nuttingi.  X  15 
Fig.  10.  Large  tridentate  pedieellaria  of  JET.  sharreri.  X  15 

The  stalk  in  figure  10  is  drawn  free  hand,  only  an  irregular  fragment  of  a 
stalk  being  found  in  the  preparations  received  from  Prof.  H.  L.  Clark. 
Fig.  11.  Histooidaris  nuttingi,  oral  view 
Fig.  12.  Eistoddaris  nuttingi,  aboral  view 


PLATE  I 


4 


tE^ 


PLATE  II 


/'■■^ 


PLATE  III 


(: 


PLATE  IV 


Figure  11 


Figure  3  2 


& 


REPORT  ON  THE  HOLOTHURIANS 

Collected  by  the  Barbados- Antigua  Expedition  from  the 
University  of  Iowa1 

Elisabeth  Deichmann 

Zoological  Museum,  Copenhagen 

The  collection  of  holothurians  contains  about  400  specimens 
divided  among  18  species.  All  the  West  Indian  species  are  repre- 
sented except  forms  typical  of  the  Florida  Keys  and  the  Greater 
Antilles.  Sluiter's  species  are  recorded  for  the  first  time  since  the 
types  were  secured.  The  apparently  new  species  is  a  redescription, 
with  a  new  name,  of  Selenka's  well-known  old  species,  Siichopus 
rigidus. 

Key  to  West  Indian  Holothurians 

a*    Appendages  present  Actinopoda. 

b1    20-25   peltate  tentacles.     Respiratory   trees  present;    no   retractor 

musculature.  Holothuriidae. 

ci     Tentacle  ampute  present,  rete  mirabile.  Holothurin®. 

d*    Genital  organs  in  one  tuft.    Appendages  scattered  and 

not  in  distinct  rows. 

Anal  teeth  present.  Actinopyga. 

No  anal  teeth  present.  Holothuria. 

d^    Genital  organs  in  two  tufts;  flattened  forms  with  warts 

on  the  dorsal  side.     Usually  C-shaped  bodies  among 

the  deposits.  Stichopus. 

c2     Tentacle  ampull®  not  present.    Usually  no  rete  mirabile. 

Synallactinro. 

Genital  organs  in  single  tuft.  Mesothuria. 

b2    10-20  dendroid  tentacles  present.    No  tentacle  ampullae.    Retractor 

musculature  present,  respiratory  trees  present  CucumaridaB. 


*  Most  of  the  specimens  upon  which  this  report  is  based  were  collected  by 
the  undersigned  while  a  member  of  the  Barbados-Antigua  Expedition  and  are 
now  in  the  collections  of  the  State  University  of  Iowa,  Stanford  University, 
and  the  California  Academy  of  Sciences.  I  had  originally  intended,  at  Pro- 
fessor Nutting's  request,  to  write  the  account  of  the  Holothurians,  and  pre- 
pared the  specimens  with  this  end  in  view.  Recently,  however,  Miss  Deich- 
mann has  completed  much  preliminary  (unpublished)  work  on  the  holothurians 
of  the  West  Indies  and  has  the  group  well  in  hand.  It  seems  appropriate 
therefore  that  the  report  should  embody  the  latest  results.  Mass  Deichmann 
has,  accordingly,  relieved  me  of  a  rather  difficult  task.  This  paper  is  a  con- 
tribution from  the  Hopkins  Marine  Station  of  Stanford  University. 

Certain  ecological  or  field  notes  are  interpolated  in  brackets  and  signed  with 
my  initials.    W.  K.  Fisher. 

9 


10  IOWA  STUDIES  IN  NATURAL  HISTOEY 

c1     Appendages  scattered  over  the  surface  of  the  body,  very  in- 
distinctly in  rows  on  the  ambulacra. 
10  tentacles  Thy  one. 

16-20  tentacles  Phyllophorus. 

a2     No  appendages,  no  respiratory  trees  Paractinopoda. 

b3-     Deposits:     Anchor  and  anchor  plates.     Tentacles  pinnate. 

Synaptinse. 
c1     Anchors  with  smooth  arms,  vertex  usually  with  knoblike  pro- 
jections, 
di     Stock  of  anchors  branched  irregularly.    Calcareous  ring 
without  noticeable  posterior  prolongations.  Stone  canals 
not  numerous.  Euapta. 

Anchor  longer  than  anchor  plate ;  complicated  rosettes 
are  found  scattered.  Euapta  lappa     (J.  Miiller). 

d2  Stock  of  anchor  not  branched.  Tentacles  15  or  fewer. 
Anchor  plates  rounded  in  front,  narrow  behind,  with 
few  holes,  the  largest  dentate  and  regularly  arranged. 

Synaptula. 
Normally  12  tentacles  with  10-20  digits.  Viviparous. 
Anchor  as  long  as  anchor  plate.  Small  curved  rods 
are  found  scattered.  Synaptula  hydriformis 

(Lesueur). 
b2     Deposits:     No  anchors  and  no  anchor  plates.     Tentacles  peltato- 
digitate. 
Deposits:     Six-spoked  wheels.  Chiridotinaa. 

10-14  tentacles.     Wheels  collected  in  small  papillae 

Chiridota. 
Numerous  curved  rods,  with  branched  ends,  scattered 
in  the  interambulaera.       Chiridota  rotifera  Pourtales. 

Key  to  the  Species  of  Holothuria 

a1     Slender  forms,  without  pronounced  difference  between  dorsal  and  ventral 
side;  tentacles  small, 
b*    Deposits:     Tables  and  regular  6  holed  buttons. 

ei  Pedicels  on  distinct  warts;  skin  rough  to  the  touch.  Genital 
organs  fastened  near  the  middle  of  the  body.  Cuvierian  or- 
gans very  large,  transversely  finely  striated.  Vascular  ring 
near  the  calcareous  ring.  Tables  regular,  with  6  large  holes 
in  the  brim,  buttons  with  6  large  holes,  impatiens  (Forskaal). 
c2  Pedicels  not  on  distinct  warts;  skin  smooth.  Genital  organs 
fastened  near  the  vascular  ring,  which  is  unusually  distant 
from  the  calcareous  ring,  (about  2  cm.  in  specimens  10-15  cm. 
long).  Cuvierian  organs  small.  Tables  with  4  small  holes 
in  the  corners  of  the  disk  or  a  complete  ring  of  small  holes; 
buttons  with  6  holes  varying  from  large  to  very  small;  but- 
tons with  numerous  holes  are  often  found. 

arenicola   (Brandt). 
b2    Deposits:     Tables  (usually  with  completely  reduced  disk)  and  den- 


HOLOTHURIANS  OF  BARBADOS  AND  ANTIGUA       11 

tate  rods.    Color  dark  reddish  brown  or  more  faded,  usually  two  rows 
of  dark  spots  on  the  dorsal  side.    Tentacles  and  pedicels  yellow. 

surinamensis  Ludwig. 

a2     Flattened  forms,  with   fewer   appendages  on  the   dorsal  side,   often  on 

warts,  and  numerous  soft  pedicels  on  the  ventral. 

b*     Deposits:     No  tables,    only   scattered  rods,    with  branched    ends 

(never  spinous).     Uniform  dark  brown  or  pale  brown;   tentacles 

very  large  and  bushy.  glaberrima  Selenka. 

b2     Deposits:     Tables,  together  with  plates  or  buttons. 

c1  Tables  high,  simple,  with  small  to  rudimentary  disk.  Skin  not 
stiff  with  spicules, 
d*  Perforated  plates,  biscuit-like  with  many  small  holes ; 
some  have  larger  holes,  often  only  four,  and  they  are 
more  irregular.  20  tentacles;  dorsal  warts  often  indis- 
tinct. Color  uniform  dark  with  paler — reddish  or  pink 
— underside;  space  around  base  of  pedicels  dark  (very 
small  specimens  6  cm.  long  may  be  sand-colored). 
Stone  canals  numerous,  in  two  tufts.    Skin  thick. 

mexicana  Ludwig. 
d2  Perforated  plates  with  usually  four  larger  central  holes 
and  often  accessory  holes  in  the  brim;  edge  dentate. 
20-25  tentacles.     Dorsal  warts  generally  very  distinct, 
in  longitudinal  rows.     Color  in  alcohol  dark  brownish 
and  grey,  sprinkled  with  small  white  dots,  arranged  in 
circles    around  the   bases   of   the    dorsal   appendages. 
Color  in  life,  Indian  and  ocher  red  above,  with  two 
rows  of  dark  reddish  brown  spots  and  very  numerous 
small  dull  green  spots,  sometimes  forming  a  net  design ; 
ventral  pedicels  greenish  yellow  against  dull  Indian  red. 
Stone  canal  single,  well  developed.         grisea  Selenka. 
c2     Tables  low,  with  large  disk  with  knobbed  brim  and  secondary 
rods,  which  unite  with  the  spire  so  that  the  tables  look  as  if 
they   had   numerous   rods   in   the   spire.     Buttons    strongly 
knobbed,  with  6  holes  in  the  dorsal  buttons,  10  in  the  ventral ; 
some  few  are  flat.     Supporting  rods  short  and  broad,  with 
few  holes.     Skin  stiff  from  spicules.     Color  in  spirit  dirty 
white.    In  life,  sand  color  with  two  rows  of  dull  brown  mot- 
tlings  above  and  often  a  rusty  stain  on  ventral  surface.  Tenta- 
cles whitish,  very  small,  and  ventrally  placed.        fossor  n.sp. 

Holothuria  impatiens  (Forskaal) 
Fistularia  impatiens  Forskaal,  1775,  p.  121,  pi.  XXXIX,  iigt  B. 
Holothuria  hotellus  Selenka,  1867,  p.  335. 

Holothuria  impatiens  Lampert,  1885,  p.  65  (complete  list  of  references). — 
Theel,  1886,  p.  233.— -Fisher,  1907,  p.  666,  pi.  LXIX  fig.  4a.— Clark,  1901  b, 
p.  259;  1901,  p.  494;  1919,  p.  63.-^luiter,  1910,  p.  333. 

The  single  specimen  is  typical  and  well  developed  in  every  respect. 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

This  form  seems  never  to  be  abundant ;  perhaps  it  lives  below  tide 
mark.  Very  few  specimens  are  known  from  the  West  Indies  and 
we  know  very  little  about  its  distribution.  It  has  been  taken  from 
Tortugas,  Porto  Rico,  and  Tobago ;  not  at  Bermuda. 

This  species  can  not,  for  the  present,  be  separated  from  the  form 
which  occurs  in  the  Pacific  Ocean,  as  Selenka  already  has  pointed 
out. 

1  specimen,  English  Harbor  Point,  Antigua,  among  small  rocks. 

Holothuria  surinamensis  Ludwig 
Eolothwria  sivrmamensis  Ludwig,  1874,  p.  Ill,  fig.  27. — Theel,  1886  a,  p.  210; 
1886  b,  p.  7.— Heilprin,  1889,  p.  136.— Clark,  1899,  p.  133;  1901,  p.  259; 
1919,  p.  63.— Verrill,  1907,  p.  322.— Sluiter,  1910,  p.  332.— Crozier,  1914,  pp. 
233-297;  1917,  p.  560-566. 

This  form,  (Plate  1,  fig.  1,)  which  is  known  only  from  the  West 
Indies,  is  very  nearly  related  to  H.  imitans  from  Panama  and  Lud- 
wig has  regarded  them  as  identical,  while  Theel  keeps  them  separate. 
The  tables  are  about  twice  as  large  as  in  H.  imitans,  which  seems  to 
be  a  rarer  form,  since  few  specimens  are  reported  in  any  collection. 

The  shape  of  this  species  is  very  variable,  ranging  from  strongly 
contracted,  short  specimens  to  completely  extended  forms.  Further 
this  form  is  able  to  multiply  by  fission  (Crozier)  and  peculiar  short 
forms  with  incomplete  tentacle  crown  frequently  occur.  The  color 
varies  in  alcohol  from  pale  brownish  to  very  dark  and  nearly  all 
specimens  have  a  double  row  of  dark  spots  on  their  back.  The  de- 
posits are  so  characteristic  that  no  confusion  is  possible  with  other 
species  known  at  present.  An  interesting  fact  is  that  in  a  very  small 
specimen  the  tables  have  a  well  developed  disk,  which  is  very  fragile 
and  easily  broken ;  the  teeth  on  the  top  of  the  spire  are  also  better 
developed  in  this  young  specimen  and  the  rods  with  dentate  edge 
are  mostly  developed  with  a  series  of  holes  along  the  edge. 

The  internal  anatomy  shows  nothing  peculiar  and  in  most  cases 
is  difficult  to  study,  as  the  animals  often  eviscerate  themselves,  or 
they  are  found  in  regenerating  stages. 

Ranges  from  Surinam,  the  type  locality,  to  Bermuda. 

130  specimens  from  Falmouth  and  English  Harbor,  Antigua;  2 
from  Barbados. 

[This  very  abundant  species  at  Antigua  has  two  color  phases 
which,  so  far  as  our  observations  extended,  are  characteristic  of 
different  habitats.  A  darker,  more  reddish  or  chocolate  brown 
variety  with  pale  brownish  or  brownish-pink,  somewhat  flesh-colored, 


HOLOTHURIANS  OF  BARBADOS  AND  ANTIGUA   13 

tentacles  occurred  at  English  Harbor,  under  rocks  on  the  sheltered 
side  of  the  Point,  where  a  mauve-tinted,  branching  Porites  was 
common. 

The  animals  were  sluggish  and  were  living  in  such  a  way  that  the 
body  was  surrounded  by  stones,  or  stones  and  sand.  At  low  tide 
they  were  always  covered  by  a  few  inches  of  water,  which  on  still 
days  became  very  warm.  In  the  laboratory  two  species  of  Fierasf&r 
were  recovered  from  the  cloaca  of  some  specimens  being  narcotized. 

The  other  form,  somewhat  slenderer  in  habit  and  of  a  yellowish 
brown  color,  with  yellow  tentacles,  was  exceedingly  common  in  Fal- 
mouth Harbor,  in  shallow  water  where  it  fairly  swarms  among  coral- 
lines and  under  stones  in  the  eel-grass  area.  It  is  found  where  the 
water  has  receded  at  low  tide,  and  hence  is  very  tolerant  to  heat  and 
exposure.  The  shallow  water  in  which  they  occur  becomes  very 
warm  at  mid-day  and  the  animals  are  sometimes  washed  up  on  the 
beach  or  rolled  around  the  edge,  kept  in  motion  by  a  ripple.  They 
are  always  alive.  They  like  very  much  an  erect  tufted  or  branched 
coralline,  but  are  even  commoner  under  rocks. 

Owing  perhaps  to  its  tough  constitution  it  is  more  difficult  to  kill 
with  narcotizing  reagents  than  other  species  of  Holothuria.  In  life 
the  animals  are  usually  stained  with  a  coating  of  fine  silt  or  mud 
which  adheres  to  their  skin  and  partly  obscures  the  rich  brown 
coloring,  upon  which  are  marbling  and  spots  of  dark  brown.  The 
papillae  are  rather  prominent,  unequal  and  pointed. 

In  aquaria  they  become  restless,  like  the  other  variety. 

— W.  K.  F.] 

Holothuria  arenicola  Semper 
Holothuria  maculata  Brandt,  1835,  p.  46-47,  (Sporadipus,  subgenus  Acolhos). — 

Ludwig,  1881,  p.  595;  1883,  p.  156-157;  167-168.— Lampert,  1885,  p.  73.— 

Sluiter,  1910,  p.  332. 
Holothuria  aremcola  Semper,  1868,  p.  61.  pis.  XX,  XXX,  fig.  13,  XXXV,  fig. 

4.— Theel,  1886  a,  p.  222. 
Holothuria  rathbuni  Lampert,  1885,  p.  73. — Theel,  1886  a,  p.  268.— Clark,  1901 

a,  p.  343;  1901  b,  p.  259,  pi.  XVII,  fig.  7-10;  1919,  p.  63.— Verrill,  1901, 

p.  37,  fig.  6a-b,  7;  1907,  p.  145,  fig.  37.— Sluiter,  1910,  p.  332. 

This  species  is  one  of  the  commonest  in  the  West  Indies  and  can- 
not be  confused  with  any  other,  -as  its  outer  appearance  is  so  very 
characteristic,  a  long  slender  body,  tapering  toward  both  ends  and 
small  terminal  tentacles.  In  the  internal  anatomy  the  unusually 
long  distance  of  the  vascular  ring  from  the  calcareous  ring  is  the 
most  remarkable  feature. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  deposits  are  of  the  very  common  type,  tables  and  6-holed 
buttons.  There  is  a  very  wide  range  of  variation,  in  individual 
specimens  as  well  as  in  the  specimens  from  the  same  locality. 

The  tables  have  from  4  holes  to  a  complete  ring  of  holes  in  the 
disk ;  apparently  the  tables  with  only  4  holes  are  commonest  in  the 
larger  specimens  and  they  have  a  low  spire,  with  single  cross-beam, 
ending  in  few  (8-12)  teeth.  Tables  with  higher  spire  are  common 
in  the  small  specimens  and  also  found  in  the  pedicels  of  the  larger. 

The  6-holed  buttons  have  large  or  small  holes ;  in  the  small  speci- 
mens, where  the  buttons  form  only  a  thin  layer,  they  are  in  nearly 
equal  numbers;  in  the  large  specimens,  where  the  buttons  form  the 
dominating  layer,  the  small-holed  are  most  numerous,  but  here  also 
is  variation ;  in  some  preparations  not  a  single  large-holed  button 
can  be  found ;  in  others  it  is  difficult  to  say  which  kind  is  the 
commoner. 

The  supporting  rods  vary  from  simple  ones,  with  few  terminal 
holes  and  two  larger  on  the  middle  (where  they  are  broadest),  to 
buttons  with  two  rows  of  many  small  holes.  The  end  plate  seems 
to  be  the  most  constant  deposit,  with  6-10  larger  holes  in  the  middle, 
and  a  variable  large  number  of  smaller  holes  in  the  outer  part. 

This  common  form  is  known  in  two  variations,  one  with  small 
spots  irregularly  dotted  over  the  body  and  one  with  two  rows  of 
large  dark  spots  on  the  back.  For  the  present  these  forms  can  be 
separated  only  by  their  coloration,  but  as  they  seem  to  occur  in 
absolutely  different  localities,  it  will  be  natural  to  keep  them  separ- 
ate, at  least  as  varieties. 

An  interesting  fact,  which  has  long  been  known,  is  that  these  two 
forms  occur  in  both  the  Pacific  and  the  Atlantic  Ocean.  At  least 
we  are  unable  to  find  any  differences,  and  the  two  varieties  seem 
also  to  be  restricted  to  different  localities  in  the  Pacific. 

The  type  locality  was  the  Bonin  Islands  where  Brandt  found  the 
small  spotted  form  {H.  maculata  Brandt).  The  same  is  common  in 
the  gulf  of  Panama  and  can  not  be  distinguished  from  the  specimens 
from  the  Atlantic  side  of  Panama,  or  the  specimens  from  Barbados. 

Brandt's  species  was  united  with  Semper 's  H.  aremcola  and  as 
the  name  maculata  is  preoccupied  by  a  Synapta,  the  name  arenioola 
should  be  preferred ;  but  both  names  have  been  used,  without  rule. 

The  name  rafhbuni  was  introduced  by  Lampert  (1885)  who  named 
a  species  from  Bahia  secured  by  Rathbun.  From  the  description 
given  by  Rathbun  it  is  quite  evident  that  it  is  H.  arenioola,  which 


HOLOTHURIANS  OF  BARBADOS  AND  ANTIGUA   15 

is  known  from  this  locality,  the  only  difference  being  that  Kathbun 
mentions  a  knobbed  body,  which  doubtless  originated  from  one  of 
the  species  of  Thyone  which  he  examined  from  the  same  locality. 

The  name  rathbuni  was  later  applied  to  this  species,  first  to  the 
small  spotted  form,  by  Clark,  1901,  who  described  and  figured  the 
spicules;  and  later  also  to  the  large  spotted  form  by  Verrill,  1904-07, 
who  figured  specimens  from  Bermuda.  Sluiter,  1910,  seems  to  use 
the  name  rathbuni  only  for  the  small  spotted  form,  and  says  of  H. 
maculata,  which  he  also  found,  that  he  is  unable  to  separate  the 
West  Indian  from  the  Pacific  specimens. 

36  specimens  from  Pelican  Isl.  Barbados.  1  specimen  from  The 
Crane,  E.  Pt.  Barbados.  17  specimens  from  English  Harbor,  An- 
tigua. Common  under  rocks,  entirely  uncovered  by  low  tide  at 
Pelican  Island,  sluggish, 

Holothuria  grisea  Selenka 

Holothuria  grisea  Selenka,  1867,  p.  328,  pi.  18,  fig.  251— Semper,  1868,  p.  92. 
— - Greef,  1882,  p.  158.— Ludwig,  1882,  p.  26— Lampert,  1885,  p.  85.— Theel, 
1886,  p.  214.— Clark,  1901,  p.  258;  1919,  p.  63. 

Type  locality,  Haiti.  This  form,  which  seems  never  to  be  abun- 
dant, has  a  very  wide  range,  nearly  the  same  as  that  of  H.  mexicana, 
and  is  said  to  occur  also  on  the  west  coast  of  Africa  (Rolas,  Greef, 
Z.  Anz.  Vol.  V,  No.  105, 1882) .  It  is  on  the  Atlantic  side  of  Panama, 
along  with  floridana  on  the  same  coral  rocks.  At  Florida  it  just 
touches  the  limit  of  floridana,  but  can  hardly  be  said  to  belong  to 
the  fauna  of  Florida.  It  ranges  as  far  south  as  Sao  Paulo  and 
Eio  Janeiro. 

The  coloration  of  preserved  specimens  is  very  constant,  being  dark 
grey  or  brown,  with  small  white  spots  arranged  in  rings  around  the 
bases  of  the  dorsal  appendages.  These  spots  are  the  plates,  which 
are  accumulated  in  heaps  in  the  skin.  The  dorsal  warts  are  promi- 
nent and  increase  in  number  with  advancing  age.  It  has  been 
supposed  to  be  the  young  of  floridana  but  can  very  easily  be  dis- 
tinguished. The  spicules  are  quite  different  and  there  is  never,  even 
in  the  largest  specimen,  more  than  one,  free,  well  developed  stone 
canal. 

The  present  material  indicates  that  the  number  of  tentacles  is  not 
always  20,  as  Selenka  observed,  but  varies  to  23-25. 

4  specimens  from  Falmouth  Harbor,  2  from  English  Harbor, 
Antigua. 


16  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

[The  name  grisea  is  a  misnomer  for  this  Harlequin  of  West 
Indian  holothurians.  All  the  specimens  which  I  have  seen  are  red 
in  life  with  two  rows  of  dark  reddish  brown  spots  along  the  back, 
which  is  peppered  with  dull  green  spots  of  small  size,  often  in  a 
reticulate  design.  The  prominent  lateral  papillae  are  usually  lighter 
and  brighter  than  the  ground  color  of  the  back  which  is  not  uniform 
but  is  a  marbling  of  Indian  and  ocher  red,  verging  in  places  on  dull 
orange  vermilion.  The  ventral  pedicels  are  greenish  yellow  against 
dull  Indian  red.    Tentacles  yellow  with  brown  ends. 

This  form  is  found  under  rocks  just  below  high  tide,  and  is  ap- 
parently nocturnal.  It  is  usually  soiled  by  mud  so  that  it  must  be 
scrubbed  to  reveal  the  true  colors.  It  was  taken  in  eel-grass,  at  the 
surface  of  the  sand  and  mud,  English  Harbor.  It  is  very  sluggish 
in  the  day  time,  especially  when  the  tide  is  out,  but  at  night,  in 
aquaria,  is  active  for  a  genus  the  members  of  which  are  not  given 
to  roving.— W.  K.  F.] 

Holothwria  mexicana  Ludwig 

Jlolothwria  mexicana  Ludwig,  1874,  p.  101,  fig.  47. — Lampert,  1885,  p.  85. — 

Theel,  1886,  p.  215.— Clark,  1901  b,  p.  258;  1919,  p.  63. 
Holothwria  afrioana  Theel,  1886,  p.  174,  pi.  VIII,  fig.  7. 
Holothuria  floridana  Edwards,  1905,  p.  383-384;  1908,  p.  236-301.— Clark,  1919, 
p.  63. 

The  type  locality  is  not  known ;  the  label  was  marked  Mexico.  It 
is  the  largest  of  the  two  West  Indian  holothurians,  which  are 
characterized  by  their  numerous  stone  canals  and  deposits  in  form 
of  tables  and  small  plates  or  rosettes  and  it  has  been  suggested  that 
mexicana  was  the  full  grown  form  of  floridana  (Edwards,  1905, 
Science  XXI,  p.  383-384;  and  1908,  Biometrika,  p.  236-301).  The 
two  forms  are  different.  H.  floridana  has  exclusively  rosettes,  while 
some  few  may  have  their  branches  united  to  form  perforated  plates 
resembling  those  of  mexicana.  H.  mexicana  has  two  kinds  of  plates, 
biscuit-formed  with  small  holes  and  some  with  fewer,  larger  holes. 
In  external  appearance  the  two  forms  are  quite  different ;  floridana 
is  variable  in  color,  spotted  or  uniformly  colored  and  is  not  thick- 
skinned.  With  the  exception  of  very  small  specimens,  mexicana 
is  always  uniform  dark  colored  with  paler  ventral  side.  In  a  single 
specimen  in  the  present  collection  large  dark  spots  also  are  found 
on  the  ventral  side.  The  skin  in  young  specimens  is  thick  and 
leathery.  Their  distribution  is  different.  In  some  localities  in  Cuba 
and  at  a  single  point  in  Florida  the  areas  of  distributon  overlap, 


HOLOTHUEIANS  OP  BAKBADOS  AND  ANTIGUA       17 

but  elsewhere  mexicana  is  found  only  in  the  eastern  part  of  the  West 
Indian  waters,  to  Curacoa,  while  floridana  ranges  from  the  Keys 
of  Florida  to  Colon,  Panama.  Mexicana  is  undoubtedly  identical 
with  H.  africana  Theel  from  West  Africa. 

Falmouth  Harbor,  Antigua. 

\Hotothuria  mexicama  was  common  in  Falmouth  Harbor,  in  eel- 
grass,  along  with  Diadema  {Centr  echinus) ,  Toxopneustes  variegatus 
and  Tripneustes  escvlentus.  In  the  shallow  water  which  became 
quite  warm  at  noon,  were  quantities  of  Manicina  corals,  and  Mille- 
pora  aicicornis  of  the  most  branched  form.  The  animals  rest  motion- 
less upon  a  bottom  of  very  fine  sand  or  mud,  often  slimy  with  organic 
matter,  and  the  fine  particles  adhere  to  the  skin  of  the  holothurians. 
In  aquaria  at  night  the  animals  were  more  active  than  in  the  same 
situation  during  day. 

The  color  is  some  shade  of  brown,  often  nearly  black,  with  pale 
yellowish,  pale  brownish  or  pink  ventral  surface.  Rarely  the  ventral 
side  has  large  dark  brown  spots. — W.  K.  F.] 

Halothuria  glaberrima  Selenka 
Holothuria  glaberrima  Selenka,  1867,  p.  328,  pi.  XVIII,  fig.  57-58.— Semper, 

1868,  p.  92.— Lampert,  1885,  p.  65;  1896,  p.  56-59.— Theel,  1886,  p.  33  — 

Clark,  1901,  p.  259;  1919,  p.  63.— Sluiter,  1910,  p.  333. 
Eolothuria  Ivhrica  var.  glaberrima  Mitsukuri,  1912,  p.  96. 

This  form  seems  to  occur  all  over  the  West  Indies ;  it  is  not  found 
at  Bermuda.  It  is  known  from  Honduras  and  many  localities  on 
the  north  coast  of  South  America.  Without  doubt  Selenka  is  in 
error  in  recording  it  from  the  Gulf  of  Panama.  Lampert  has  clearly 
pointed  out  the  differences  between  this  form  and  the  nearly  related 
H.  lubrica,  with  which  it  has  been  confused.  The  color  is  uniformly 
brown  with  paler,  more  greyish  ventral  side ;  sometimes  a  single  pale 
brown  specimen  occurs  among  numerous  typical. 

52  specimens  from  English  Harbor,  Antigua.  2  specimens  from 
Bathsheba,  Barbados. 

[The  habitat  of  this  species  is  entirely  different  from  that  of  any 
other  holothurian  encountered  by  the  expedition.  It  is  found  only 
on  rocky  shores,  exposed  to  the  buffeting  surges  of  the  open  sea, 
where  it  dwells  in  miniature  basins  of  the  rocks  associated  with 
Echinometra  lucunter.  These  little  hollows  are  the  forms  once 
occupied  by  Echinometra.  When  the  tide  is  out,  the  hollows  retain 
usually  a  little  water,  which  is  replenished  with  air-charged,  foamy 
brine  each  time  a  breaker  cascades  back  into  the  sea.    I  noticed  that 


18  IOWA  STUDIES  IN  NATUEAL  HISTORY 

the  tentacles  are  kept  expanded  in  such  little  pools.  In  hollows  of 
sufficient  size,  several  animals  are  wedged  tightly  together.  They 
are  difficult  to  dislodge,  and  it  is  easy  to  see  how  the  unusual  number 
of  tube-feet  aid  the  animal  in  clinging  where  the  clawing  waves  are 
seldom  at  rest.  There  is  usually  a  plentiful  growth  of  short, 
tough  kelp  where  the  holothurians  live.  This  kelp  overhangs  the 
edges  of  the  little  basins  in  which  two  or  three  of  the  animals  are 
domiciled  in  such  a  way  as  practically  to  hide  them. 

The  species  is  easily  recognized  by  its  very  dark  brown  color, 
large,  practically  dendritic,  tentacles  and  very  crowded  ventral 
pedicels. — W.  K.  F.] 

Holothuria  fossor  n.  sp. 
Stichopus  rigidus  Selenka,  (partly),  1867,  p.  317,  pi.  XVIII,  fig.  30-31. 
Holothuria  rigida  Semper,  1868,  p.  79— Theel,  1886,  p.  231. 
Holothuria  pleuripus  Sluiter,  1910,  p.  333. 
Holothuria  hypamma  I  Clark,  1921,  p.  178. 
Holothuria  hypamma  Clark,  1922,  p.  231. 

Length  85  mm.  Ventral  side  flattened,  dorsal  somewhat  arched ; 
skin  very  stiff  and  rigid,  but  thin ;  mouth  ventral,  the  crown  of  very 
small  and  pale  tentacles  surrounded  by  a  collar  of  papillae;  anus 
terminal. 

Color,  on  dorsal  side  greyish,  with  about  12  pairs  of  indistinct 
spots;  ventral  surface  white,  rusty  on  the  middle;  and  also  a  ring 
of  rusty  red  pigment  is  found  around  the  end  of  the  pedicels.  The 
appendages  are  small  and  inconspicuous.  On  the  dorsal  side,  small 
wart-like  papillae  of  different  sizes;  they  are  numerous  along  the 
edge;  ventrally,  small  retracted  pedicels  are  found,  not  crowded; 
they  are  mostly  retracted  in  the  odd  ambulacrum,  laterally  they  are 
more  conspicuous  on  account  of  the  pigmentation. 

A  small  and  delicate  calcareous  ring  is  present;  the  posterior 
edge  is  undulated;  the  radialia  are  broad,  squared,  with  a  deep 
anterior  notch ;  the  interradialia  are  small,  with  the  usual  anterior 
tooth.  Tentacle  ampullae  small  and  slender.  The  vascular  ring  is 
about  10  mm.  distant  from  the  calcareous  ring;  one  slender  Polian 
vesicle  is  present  and  a  small  stone  canal,  with  small  head,  free  on 
the  right,  partly  attached  to  the  mesentery.  The  genital  tuft  con- 
tains numerous  long  and  dichotomously  branched  tubes,  some  of 
which,  in  the  present  specimen,  are  longer  than  the  animal.  Two 
respiratory  trees,  as  usual  the  left  is  entangled  in  the  well-developed 


HOLOTHURIANS  OF  BARBADOS  AND  ANTIGUA       19 

rete  mirabile.    The  muscle  bands  are  broad  and  thick;  the  circular 
musculature,  very  feeble.    Plate  II. 

According  to  Selenka  the  Cuvierian  organs  are  branched.  There 
was  found  a  brown  mass  near  the  base  of  the  right  respiratory  tree, 
but  it  was  impossible  to  trace  any  structure  in  it. 

Deposits :  In  the  body  wall  is  found  a  layer  of  densely  placed 
large  tables,  underneath  a  thick  layer  of  strongly  knobbed  buttons. 

The  tables  have  a  knobbed  margin,  the  disk  (.059  mm.  diam.) 
has  a  large  central  hole  and  several  marginal,  but  often  the  primary 
disk  is  covered  by  a  secondary  network,  which  hides  the  original 
structure ;  the  spire  has  numerous  blunt  teeth,  which  unite  and  form 
a  network.  From  the  edge  of  the  disk  arise  rods  which  unite  with 
projections  from  the  spire.  The  tables  are  larger  and  more  com- 
plicated dorsally;  ventrally  they  are  smaller  (.044  mm.)  and  repre- 
sent different  stages  of  development.  The  buttons  are  smallest  and 
most  knobbed  dorsally,  where  they  have  six  holes  and  are  about  half 
as  long  as  the  diameter  of  the  tables  (.039  mm.)  ;  ventrally  they  have 
ten  to  twelve  holes  and  they  are  twice  as  long  and  often  nearly  flat 
(.0604  mm.). 

In  the  dorsal  papillse  are  numerous  curved  supporting  rods 
(.0832  mm.)  but  no  end  plate;  in  the  pedicels  the  supporting  rods 
(.0858  mm.)  are  nearly  straight;  they  are  broad,  with  few  holes  in 
the  ends  and  on  the  middle;  often  they  have  a  low  longitudinal 
ridge ;  a  small  end  plate  is  present. 

In  the  pedicels  the  tables  are  especially  small  and  of  very  variable 
development ;  Selenka  most  probably  described  these  simple  tables 
as  those  with  eight  rods  in  the  spire.  His  spinous  ellipses  are  with- 
out doubt,  the  dorsal  tables,  seen  in  oblique  position. 

Clark  first  noted  that  the  rigida  f rom  Florida  was  different  from 
the  species  of  the  Society  Islands,  which  is  regarded  as  the  type 
(1921,  p.  178).  He  regards  the  West  Indian  species  as  identical 
with  his  H,  hypamma  from  Murray  Islands  (1922) .  The  undeveloped 
tables  in  the  pedicels  of  the  West  Indian  species  resemble  the  average 
tables  of  H.  hypamma  (.054  mm.) ;  but  those  found  in  the  body  wall 
of  H.  fossor  are  large  and  much  more  complicated.  The  buttons  are 
entirely  different ;  they  are  much  more  knobbed  in  the  West  Indian 
species,  the  holes  are  smaller  and  they  never  have  the  middle  bar 
projecting  over  the  ends  of  the  buttons,  as  in  H.  hypamma, 

Sluiter  has  recorded  a  specimen  of  H.  pleuripus  (Haaeke)  from 
Kingston,  which  he  states  agrees  with  the  description  given  by  Theel 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

of  some  specimens,  in  the  Godeffroy  Collection,  from  Fiji  and  Tahiti. 
Undoubtedly  Sluiter  is  dealing  with,  an  example  of  H.  fossor,  which 
may  be  inferred  from  Theel's  description  of  H.  pleuripus,  more 
easily  than  from  Selenka 's  description  of  H,  rigida.  It  has  been 
possible  to  make  sure  of  the  identification  by  comparing  spicules  of 
H.  fossor  with  those  of  Selenka 's  type  of  JET.  rigida  in  the  Museum 
of  Comparative  Zoology. 

Inasmuch  as  the  species  from  the  Society  Islands  is  the  genuine 
Holothwria  rigida  (Selenka)  and  that  from  the  West  Indies  is 
different  from  Clark's  H,  hypamnta  (Murray  Islands),  it  becomes 
necessary  to  name  the  West  Indian  form.  Dr.  Fisher  has  proposed 
the  name  H .  fossor,  on  account  of  its  burrowing  habit. 

1  specimen,  Falmouth  Harbor,  Antigua. 

[This  species  has  less  ' 'behavior"  than  a  sluggish  chiton.  It  was 
found  under  rocks,  which  rested  on  sand,  Falmouth  Harbor,  and 
was  never  uncovered  by  tide.  It  was  deeply  buried,  after  the  man- 
ner of  Brissus  brissus,  and  probably  does  not  come  to  the  surface, 
unless  at  night.  In  the  aquarium  it  was  very  sluggish  both  by  night 
and  by  day.    In  life  it  is  covered  with  fine  sand  grains. — W.  K.  F.] 

Actinopyga 
Anal  teeth  very  small,  dorsally  warts,  ventrally  pedicels. 

Color  uniform  brown,  with  a  greenish  shade,  (the  green  pigment  is  ex- 
tracted in  alcohol).  Deposits:  Tables  with  numerous  holes  in  the  brim 
and  medium  sized  spire  ending  in  numerous  teeth,  buttons  with  6  holes, 
elliptical  and  often  curved  and  irregular.  Cuvierian  organs  present.  20 
tentacles.    Small  form  (4-5  cm.).  Actinopyga  parvula  (Selenka). 

Actinopyga  parvula  (Selenka) 

Mulleria  parvula  Selenka,  1867,  p.  314,  pi.  XVIII,  fig.  17-18.— Semper,  1868, 
p.  77.— Lampert,  1885,  p.  76.— Theel,  1886,  p.  199.— Sluiter,  1910,  p.  333. 

Eolothuria  captiva  Ludwig,  1874,  p.  32.— Lampert,  1885,  p.  68. — Theel,  1886, 
p.  220.— Verrill,  1907,  p.  321.— Crozier,  1917,  p.  560.— Clark,  1919,  p.  63,  64. 

Actinopyga  parvula  Clark,  1919,  p.  63. — Deichmann,  1921,  p.  199-215,  text  fig. 
1-3,  5-7. 

As  usual  this  form  is  abundant.  All  kinds  of  animals  are  present, 
from  complete,  normal  ones  to  small  balls  of  skin,  lacking  either 
oral  or  anal  end,  representing  regenerating  stages.  The  anal  teeth 
are  very  small  and  usually  this  species  has  been  recorded  as  IT. 
captiva  Ludwig.  Even  when  the  anal  teeth  are  not  found,  in  re- 
generating stages,  this  species  is  easily  recognized  by  its  comparative- 
ly small  size,  its  uniform  brown  color,  and  the  peculiar  green  pig- 


HOLOTHUBIANS  OF  BARBADOS  AND  ANTIGUA       21 

ment  which  the  body-wall  contains.  None  of  the  West  Indian  holo- 
thurians  with  dorsal  warts  and  ventral  crowded  pedicels*  has  spicules 
developed  as  tables  and  buttons.  The  type  was  described  from 
Florida.    It  is  known  from  the  West  Indies  to  Bermuda. 

93  specimens  from  English  Harbor,  Antigua.    5  from  Barbados. 

[This  species,  the  Holothuria  captiva  of  the  "  Narrative/ '  was 
abundant  under  stones  at  Harbor  Point,  English  Harbor,  in  the 
same  locality  as  H.  swrinamensis,  and  was  found  sparingly  under 
stones  at  Falmouth  Harbor.  It  is  very  warty,  rich  bright  brown, 
with  yellow  tentacles  and  not  over  two  and  a  half  inches  long.  It 
shoots  out  its  delicate  viscid  Cuvierian  organs  with  great  freedom 
and  precision.  A  small  spider  crab  which  was  bombarded  with  the 
Cuvierian  filaments  was  visibly  embarrassed  as  the  threads  stretched 
out  at  each  movement  of  his  legs.  He  solved  the  difficulty  by  eating 
the  threads.— W.  K.  F.] 

Stichopus 

Deposits:  Tables  and  small  C-shaped  bodies,  1-2  times  as  large  as  the  height 
of  the  tables.  Strongly  developed  warts  on  back  and  side.  Color  very 
variable,  often  greyish  brown  with  darker  spots  or  patches. 

Stichopus  badionotus  Selenka. 

Deposits:  Tables  and  C-shaped  bodies,  3-4  times  as  large  as  height  of  tables; 
only  small  warts  on  back  and  side.  Color  yellow  with  brown,  dotted  ir- 
regularly; tip  of  papillae  pale.  Stichopus  macroparentheses  Clark. 

Stichopus  badionotus  Selenka 
Stichopus  badionotus  Selenka,  1867,  p.  316,  pi.  18,  fig.  26. — Clark,  1922,  p.  55, 
pi.  2,  fig.  11-15,  (complete  list  of  references). 

The  specimens  show  the  usual  variation  in  color  and  pattern. 
This  species  ranges  from  the  Atlantic  coast  of  Panama  to  Bermuda; 
according  to  Clark,  1919,  it  does  not  occur  south  of  Antigua.  Clark 
has  compared  specimens  from  the  West  Indies  with  Stichopus  from 
the  West  Coast  of  Mexico  and  believes  that  the  two  species  are  iden- 
tical. He  also  places  Greef  *s  Stichopus  maculatus,  from  Rolas,  West 
Africa,  as  a  probable  synonym  of  badionotus, 

8  specimens,  English  Harbor,  Antigua. 

[This  conspicuous  species  was  abundant  in  English  and  Falmouth 
Harbors  among  eel-grass,  on  a  soft,  sandy  bottom. — W.  K.  F.] 

Stichopus  macroparentheses  Clark 
Stichopus  macroparentheses  Clark,  1922,  p.  61,  pi.  I,  fig.  1-7. 

The  two  specimens  are  larger  than  those  which  Clark  found  at 
Jamaica  and  Birds  Key.    Both  specimens  agree  with  the  description 


22  IOWA  STUDIES  IN  NATUKAL  HISTOEY 

of  the  type,  in  the  shape  of  the  calcareous  ring  and  the  deposits. 
They  are  not  very  well  suited  to  complete  description  as  one  speci- 
men is  flattened  and  formless  and  the  other  blown  up  to  a  thin- 
walled  sac.  It  is  apparent  that  the  pedicels  are  in  three  rows  and 
the  warts  are  small  and  inconspicuous.  The  genital  organs  are 
totally  absent  in  the  first  specimen  and  small  in  the  other.  The  color 
is  yellow  or  pale  brown  with  darker  brown  spots,  and  the  ends  of  the 
papillae  are  pale.  They  are  said  in  a  younger  stage  to  resemble 
young  S.  badionotus. 

2  specimens  from  English  Harbor,  on  sand  among  eel-grass. 

Mesothuria 

Skin  semitransparent.  Deposits:  Tables  alone,  with  large  central  hole,  sur- 
rounded by  smaller;  spire  high  and  slender  with  up  to  3-4  cross  beams 
ending  in  four  blunt  teeth.  Few  pedicels,  dorsally  papillee.  Small  form 
(1-2  cm.).  Mesothuria  verrilli  Theel. 

Mesothuria  verrilli  (Theel) 

Molothuria  verrilli  Theel,  1886  b,  p.  6— Marenzeller,  1893,  p.  79,  pi.  I,  fig.  2, 

pi.  II,  ng.  2. 
Molothuria  intestinalis  Koehler,  1895,  p.  482;  1896,  p.  106.— Ludwig,  1900,  p. 

138. 
Molothuria  intestinalis  var.  verrilli  Herouard,  1896,  p.  163. 
Molothuria  magellani  ?  Sluiter,  1910,  p.  332. 
Mesothuria  verrilli  Oestergren,  1896,  p.  347. — Perrier,  1902,  p.  357,  pi.  XVI, 

fig.  22-31. 

The  single  specimen  (Plate  I,  fig.  2,)  is  less  than  10  mm.  long, 
whitish  gray  and  rough  from  the  numerous  deposits.  The  dorsal 
appendages  are  scattered  and  without  end-plate ;  ventrally  they  are 
indistinctly  placed  in  three  more  or  less  double  rows,  and  the  end 
plate  is  well  developed.  The  tables  have  a  central  large  hole  and  a 
different  number  of  marginal  holes ;  the  spire  is  very  variable  in 
height  and  upward  of  four  cross  beams  have  been  found.  It  usually 
ends  in  four  teeth. 

Sluiter  has  found  a  specimen  from  nearly  the  same  locality  which 
he  refers  to  M.  magellani  (Ludwig)  and  says  it  is  very  near  to  the 
European  M.  intestinalis  (Asc.  and  Hatke).  If  the  character  "no 
pedicels  in  the  midventral  radialia"  is  constant,  the  present  speci- 
men can  not  be  magellani.  It  may  possibly  be  M.  verrilli  Theel, 
which  has  been  recorded  from  Barbados,  but  in  a  depth  of  399 
fathoms.  The  only  difference  is  that  Theel  speaks  of  pedicels  all 
over  the  body.    He  also  describes  the  tables  with  one  to  two  cross 


HOLOTHURIANS  OF  BARBADOS  AND  ANTIGUA       23 

beams,  but  mentions  that  there  is  a  very  wide  range  of  variation  in 
the  tables.  He  does  not  figure  the  spicules.  The  present  specimen 
seems  just  as  likely  to  be  referable  to  verrilli,  normally  occurring 
at  a  great  depth  as  it  is  to  magellani,  from  the  Straits  of  Magellan. 

Both  forms  are  nearly  related  to  M.  intestinalis  to  which  Koehler 
and  Ludwig  unite  them;  Oestergren,  however,  has  compared  M. 
verrilli  with  numerous  specimens  of  the  European  intestinalis,  and 
says  that  they  are  different. 

1  specimen  from  Falmouth  Harbor,  Antigua. 

Key  to  the  Species  of  Thyone 

a1  Calcareous  ring  simple;  small  anal  teeth  present;  tentacles  of  equal  size; 
end-plate  and  supporting  rods  present  in  the  pedicels.  Deposits:  Four- 
holed  buttons  and  four-spoked  cups  with  8-12  teeth  in  the  margin.  Per- 
forated plates  and  rods  numerous  near  the  anal  end.  Color  greyish-brown, 
mottled  with  darker  brown. 
b1  Numerous  strongly  knobbed  buttons  with  small  holes,  some  few  with 
knobs  on  the  margin  and  larger  holes.     Skin  stiff  with  spicules. 

Thyone  surinamensis  Semper. 
b2     Few  buttons  with  large  holes  and  knobs  on  the  margin.     Skin  soft, 
with  few  spicules.  Thyone  suspecta  Ludwig. 

a2     Calcareous  ring  with  short  posterior  prolongations;  no  anal  teeth;  tentacles 
of  unequal  size,  the  two  ventral  being  smaller.     Deposits:     Tables  with 
reduced  spire  and  few  rosettes.    Well  developed  end-plate  but  no  support- 
ing rods  in  the  numerous  soft  pedicels, 
bi     Deposits :     Tables  with  spire  reduced  to  2  knobs  and  4  holes  in  the 
oval  disk.     No  separate  posterior  pieces  on  the  interradialia  of  the 
calcareous  ring.     Color  violet.  Thyone  trita  Sluiter. 

b2  Deposits:  Tables  with  spire  reduced  and  regular  disk  with  8  holes 
and  8  marginal  teeth.  Separate  posterior  pieces  on  the  interradialia, 
sometimes  forming  short  tails.     Color  uniform  brown. 

Thyone  constituta  Sluiter. 

Thyone  suspecta  Ludwig 
Thyone  suspecta  Ludwig,  1874,  p.  16,  pi.  6,  fig.  19. — Lampert,  1885,  p.  157. — 

Theel,  1886  a,  p.  133.— Sluiter,  1910,  p.  333.— Clark,  1919,  p.  63. 
Thyone  orasiliensis  Verrill,  1868,  p.  370. — Rathbun,  1879,  p.  141. 

The  single  specimen  (Plate  III,  fig.  2,)  is  from  the  same  locality 
as  the  type.  It  agrees  in  every  respect  with  the  description  of  the 
type  and  with  some  specimens  from  Savanilla,  Colombia,  except 
that  the  end-plate  is  either  small  or  composed  of  a  central  larger 
part  and  several  smaller  peripheral  pieces.  Many  of  the  cups  are 
poorly  developed.  This  might  seem  to  be  caused  by  the  formalin 
in  which  the  specimen  has  been  preserved,  but  in  the  anal  region 


24  IOWA  STUDIES  IN  NATURAL  HISTORY 

as  well  as  in  the  extended  introvert  the  cups  are  very  well  developed. 

The  skin  is  thick  and  soft  and  the  pedicels  are  uniformly  spread 
over  the  entire  body.  The  anal  teeth  are  present  but  not  very 
prominent.  The  spicules  are  most  numerous  in  the  anal  part,  where 
large  perforated  plates  are  accumulated  in  addition  to  the  ordinary 
buttons  which  have  large  holes  and  small  isolated  knobs  on  the  rim. 
All  stages  are  found  from  complete  bodies  to  dichotomously 
branched  ones  with  the  ends  of  the  branches  united.  The  layer  of 
buttons  is  very  scattered. 

The  cups  are  not  numerous,  they  are  four-spoked  with  12  spines 
on  the  edge.  In  the  pedicels  are  simple  supporting  rods,  nearly 
straight,  with  large  holes  and  narrowest  on  the  middle.  In  the 
introvert,  besides  numerous  cups,  are  found  heaps  of  rosettes.  The 
rods  in  the  tentacles  are  of  the  same  type  as  the  supporting  rods 
in  the  feet,  but  they  are  more  irregular  and  branched. 

The  internal  anatomy  is  normal  for  the  genus;  the  calcareous 
ring  is  simple,  deeply  incised  posteriorly,  and  anteriorly  with  large 
teeth  of  nearly  equal  size.  One  Polian  vesicle  is  present ;  one  dor- 
sally  embedded  stone  canal ;  the  muscular  stomach  is  short ;  the  long 
and  unbranched  tubes  of  the  genital  organs  are  filled  with  eggs  and 
fastened  near  the  middle  of  the  body  wall,  where  the  retractors 
arise ;  the  longitudinal  musculature  is  well  developed. 

Distribution :    Colombia  to  Barbados ;  not  common. 

1  specimen  from  Barbados. 

Thyone  trita  Sluiter 
Thy  one  trita  Sluiter,  1910. 

This  species  has  only  been  recorded  from  Barbados  and  only  the 
type  specimens  are  existing.  The  two  present  specimens  agree  well 
with  Sluiter 's  description.  The  smallest  is  very  dark,  with  a  shade 
of  violet. 

2  specimens  from  English  Harbor,  Antigua. 

Thyone  constituta  Sluiter 
Thyone  constituta  Sluiter,  1910. 

The  single  specimen  is  better  developed  than  the  type,  which  was 
found  at  Barbados.  The  calcareous  ring  has  the  same  narrow  long 
radialia  with  short  posterior  prolongations  and  the  interradialia  are 
broad  and  overlap  the  middle  of  the  radialia ;  but  the  separate  pos- 
terior pieces  form  real  short  prolongations.  As  in  T.  trita  the 
pedicels  are  numerous,  small,  and  soft,  with  well  developed  end 


HOLOTHURIANS  OP  BARBADOS  AND  ANTIGUA       25 

plate.  The  very  characteristic  tables  are,  near  the  oral  end,  more 
irregular,  with  numerous  teeth  and  holes,  instead  of  the  ordinary- 
eight  teeth  and  eight  holes.  The  rosette  shaped  bodies  are  most 
numerous  in  the  introvert  and  more  scattered  in  other  parts  of  the 
body  wall,  but  they  are  not  very  common. 
1  specimen  from  English  Harbor,  Antigua. 

Thyone  surinamensis  Semper 

Thyone  surinamensis  Semper,  1868,  p.  65,  pi.  XV,  fig.  15.— Lampert,  1885,  p- 

158.— Theel,  1886,  p.  133. 
Cucumaria  punctata  Ludwig,  1874,  p.  82. — Sluiter,  1910,  p.  335. — Clark,  191$- 

p.  63. 
Semperia  punctata  Lampert,  1885,  p.  152. 

The  specimens  (Plate  III,  fig.  1,)  except  in  minor  details  agree 
with  the  description  given  by  Semper.  The  genital  organs  are  un- 
branched,  but  so  numerous  and  twisted  around  each  other,  that 
they  appear  to  be  divided.  The  pedicels  are,  in  some  specimens,  not 
uniformly  distributed,  but  absent  from  a  narrow  strip  on  each  in- 
terradial  area.  These  animals  could  therefore  be  referred  to  Cucu- 
maria punctata  (Ludwig),  which  was  described  from  Barbados. 
The  only  anatomical  difference  is  that  the  type  of  C.  punctata  had 
5  Polian  vesicles,  while  the  present  animals  have  only  one  or  two. 
The  deposits  are  of  the  same  type — four-holed  knobbed  buttons,  and 
cups.  A  preparation  of  spicules  of  a  C.  punctata  from  Bermuda 
shows  that  the  cups  have,  besides  about  12  marginal  teeth,  a  variable 
number  of  teeth  projecting  outward.  The  same  is  the  case  of  the 
cups  from  the  present  animals.  The  spicules  from  the  animals  with 
uniformly  distributed  pedicels  can  not  be  separated  from  those  with 
naked  strips  on  the  interradialia;  it  seems  therefore  very  probable 
that  Ludwig's  C.  punctata  is  a  younger  stage  of  Thyone  surina- 
mensis. 

In  coloration  and  size  the  present  species  is  similar  to  T.  suspecta 
and  the  internal  anatomy  is  almost  identical.  In  T.  surinaftnensis 
there  are  two  kinds  of  buttons:  strongly  knobbed,  with  small  holes, 
present  in  large  number,  and  some  few  with  larger  holes  and  isolated 
knobs  on  the  margin.  These  are  perhaps  stages  of  the  strongly 
knobbed  buttons.  In  suspecta  there  is  only  one  kind  of  button,  with 
large  holes  and  isolated  knobs;  usually  they  are  larger  than  the 
average  button  in  surinamensis.  The  cups,  supporting  rods  and 
rosettes  are  of  exactly  the  same  type.  It  might  be  inferred  from 
a  mere  description,  that  the  two  species  are  the  same  and  that 


26  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

suspect  a  is  only  a  form  in  which,  the  large  layer  of  strongly  knobbed 
buttons  has  not  been  developed.  The  figures  of  the  spicules  show 
the  actual  differences,  which  are  found  in  the  two  species.  Most 
of  the  buttons  are  smaller  in  surinamensis ;  the  cups  are  larger  in 
absolute  size  and  in  proportion  to  the  buttons.  They  seem  to  have 
more  accessory  teeth  in  surinamensis,  but  that  may  be  accidental. 
The  supporting  rods  are  slightly  longer  in  surinamensis  and  often 
have  a  nearly  straight  edge.  The  holes  are  small,  while  suspecta  has 
very  large  holes  in  the  supporting  rods  and  a  very  undulated  margin. 
The  rosettes  are  much  larger  in  surinamensis  than  in  suspecta. 

Distribution:  From  northern  coast  of  South  America  to  Bar- 
bados (and  if  identical  with  Cucumaria  punctata  also  from  Ber- 
muda.)    Pelican  Island,  Barbados. 

Phyllophorus  parvum  (Ludwig) 
Thyonidium  parvum  Ludwig,   1881,  p.   54-55,   pi.   Ill,   fig.    16-18. — Lampert, 
1885,  p.  169. 

Eighteen  to  twenty  tentacles  in  two  circles  and  of  different 
length;  skin  leathery;  the  pedicels  are  not  crowded  and  only  in- 
distinctly placed  in  rows.  Deposits :  Tables  with  large  rounded  or 
squared  disk  with  two  small  central  holes  and  8-10  larger  in  the 
margin;  spire  built  up  of  two  rods  and  ending  in  few  teeth;  no 
supporting  rods;  small  end-plate.  Calcareous  ring  with  long  pos- 
terior prolongations.    Color  pale  reddish  brown  with  violet  tentacles. 

The  single  specimen  agrees  with  Ludwig 's  description.  The  ten- 
tacles are  deep  violet  and  of  varying  size.  According  to  Lampert, 
this  species  is  common  along  the  coast  of  Brazil  down  to  Eio  Janeiro. 
It  seems  never  to  have  been  taken  in  the  West  Indies. 

One  specimen  from  English  Harbor,  Antigua. 

Euapta  lappa  (J.  Miiller) 
Synapta  lappa  J.  Miiller,  1850,  p.  134. 

Euapta  lappa  Clark,  1907,  p.  73,  pi.  IV,  fig.  23-25.     (Complete  literature  list). 
1924,  p.  464,  pi.  I,  fig.  5-7. 

The  present  specimens  are  all  large  and  typical  in  color  and 
spicules.  This  species  which  is  the  largest  apodous  form  in  the  West 
Indies,  is,  according  to  Clark,  known  from  Florida  to  Tobago  and 
also  from  Teneriife  (Theel). 

2  specimens  from  Falmouth  Harbor;  2  from  entrance  of  English 
Harbor,  Antigua. 

[This  large,  showy,  and  active  synaptid  was  found  among  stones 


HOLOTHUEIANS  OP  BAEBADOS  AND  ANTIGUA       27 

at  English  Harbor  (Harbor  Point) ,  and  at  Falmouth  Harbor.  Pro- 
fessor Nutting,  in  the  narrative  of  the  Barbados-Antigua  Expedi- 
tion, p.  194,  writes  of  it  as  follows : 

"A  fully  extended  specimen  sometimes  reaches  the  length  of  two  feet  and 
looks  more  like  an  enormous  worm  than  like  anything  else.  It  is  quite  trans- 
lucent, being  thinner  walled  than  most  species,  and  the  body  is  longitudinally 
striped  with  reddish  brown  bands  and  bears  numerous  rounded  nodules  ar- 
ranged in  annular  series;  but  these  disappear  completely  when  the  animal  is 
entirely  extended,  or  in  parts  of  its  length  which  are  extended,  only  to  reap- 
pear instantly  upon  contraction.  Waves  of  such  contraction  pass  rhythmically 
along  its  length.  It  is  the  most  active  holothurian  by  far  that  I  have  ever 
seen  and  is  really  a  beautiful  object  when  in  the  aquaria  and  in  vigorous  mo- 
tion. The  feathery  tentacles  are  in  constant  activity,  waving  this  way  and 
that,  lengthening  and  shortening,  bending  gracefully,  their  frilled  edges  a  con- 
stant play  of  activity;  while  the  whole  body  is  in  rhythmical  movement,  bend- 
ing, twisting,  elongating,  retracting,  and  at  the  same  time  pulsating  with  the 
waves  of  retraction  already  referred  to,  during  which  the  hemispherical  nodules 
appear  and  disappear  as  if  by  magic  along  its  whole  length.  The  transpar- 
ency of  the  body  walls  gives  a  peculiar  delicacy  that  we  do  not  usually  asso- 
ciate with  the  ordinary  unattractive  'sea  cucumbers'. 

"Its  footless  condition  is  compensated  for  by  the  possession  of  several  pecu- 
liar features.  Doubtless  the  hemispherical  and  temporary  nodules  already  re- 
ferred to  give  it  a  hold  on  the  stones  between  which  it  worms  its  way,  and  its 
extreme  extensibility  enables  it  to  go  through  quite  narrow  holes  and  cracks, 
while  the  waves  of  contraction  serve  to  push  it  rapidly  along  either  the  sur- 
face of  the  sand  bottom  or  over  and  between  rocks.  It  can  also  swim  to  a 
limited  extent  and  will  frequently  raise  itself  on  end  in  the  aquaria  so  as  to 
assume  a  vertical  position  with  the  tentacles  exploring  the  surface  while  the 
aboral  end  rests  on  the  bottom.'' — W.K.F.] 

Synaptula  hydriformis  (Lesueur) 
Holothuria  hydriformis  Lesueur,  1824,  p.  162. 

Synaptula  hydriformis  Clark,  1907,  p.  82,  pi.  VI.     (Complete  literature).    1924, 
p.  473,  pi.  III,ng.  5,  pi.  IV,  fig.  4. 

A  single  small  specimen  about  20  mm.  long,  nearly  colorless,  with 
typical  spicules.  This  form  is  common  from  Brazil  to  Florida  and 
is  also  found  at  Bermuda  (Clark). 

One  specimen  from  Antigua. 

Chiridota  rotifera  Pourtales 

Chiridota  rotifera  Pourtales,  1851.— Clark,  1907,  p.  115,  (complete  list  of  refer- 
ences) ;  1919  p.  63.— -Sluiter,  1910,  p.  341. 

This  species  seems  not  to  have  been  taken  at  Antigua  before,  but 
it  is  a  common  form  which  according  to  Clark  has  the  same  dis- 
tribution as  S.  hydriformis. 

2  specimens  from  Antigua. 


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1921 


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1905 


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Multiplication  by  fission  in  Holothuria.  Amer.  Nat.  51,  pp. 
560-566.    New  York. 

On  some  cases  of  multiplication  by  fission  etc.    Papers  from  Dr. 
Th.  Mortensen's  Pacific  Exp.  1914-16,  Vid.  Med.  Nat.  For.  Bd. 
73,  pp.  199-215.    Copenhagen. 
L. 

A  quantitative  study  of  H.  atra  Jaeger  and  the  re-establishment 
of  JET.  floridana  Pourt.  (H.  mexicana  Ludwig).  Science  N.  S. 
Vol.  XXI,  pp.  383-384. 

Variation,  Development  and  Growth  in  J3".  floridana  Pourt., 
Biometrica,  pp.  254-301,  pis.  I-V. 

28 


HOLOTHUBIANS  OF  BARBADOS  AND  ANTIGUA       29 


Fisher  W.  K. 
1907 

Forskaal  P. 
1775 


Greef  B. 

1882 

Heilprin  A. 

1888 

Herouard  E. 
1896 


Koehler  B. 
1895 


1896 


Lampert  K. 
1885 

1896 


Lesueur  C.  A. 
1823 

Ludwig  H. 
1874 

1881a 

1881b 

1883 

1900 

Marenzeller  E 
1893 


The  Holothurians  of  the  Hawaiian  Islands,  Proc.  IT.  S.  Nat. 
Mus.  Vol.  XXXII,  pp.  637-744,  pis.  LXVI-LXXXIL 

Descriptions  animaliuxn  quae  in  itinere  orientali  observavit  P. 
Forskaal;  post  mortem  auctoris  editit  C.  Niebuhr,  pp.  121-122. 
Havnise. 

Echinodermen,  beobachtet  auf  eine  Beise  nach  der  Guinea  Insel 
Sao  Tome,  Zool.  Anzeiger,  5,  p.  158. 

Contribution  to  the  Natural  History  of  the  Bermuda  Islands. 
Proc.  Acad.  Nat.  Sci.  Phila.  Pt.  40,  pp.  302-328. 

Note  preliminaire  sur  les  Holothuries  provenant  des  dragages  du 
yacht  "Princesse  Alice".  Bull,  de  la  Soc.  Zool.  de  Prance,  T. 
XXI,  pp.  163-168. 

Dragages  profondes  executes  a  bord  du  "Caudan" '  dans  le 
golfe  du  Gascogne  Aout — Septembre  1895.  Bapport  prelim- 
inaire sur  les  echinodermes,  Bev.  Biol,  du  Nord  de  la  Prance. 
Vol.  Vn,  pp.  478-496. 

Be*sultats  scientifique  de  la  campagne  du  "Caudan"  dans  le 
golfe  de  Gascogne  Aout — Septembre  1895.  Ann.  de  1 'University 
de  Lyon,  Fasc.  I,  Vol.  XXVI,  pp.  33-127,  pis.  I-IV. 

Die  Seewalzen,  Beisen  im  Archipel  der  Philippinen  von  Dr.  C. 
Semper,  Theil  II,  Bd.  IV,  Abt.  Ill,  pp.  310,  pi.  1.  Wiesbaden. 
Die  von  Dr.  Stuhlmann  in  den  Jahren  1888  und  1889  an  der 
Destkust  Afrikas  gesammelten  Holothurien.  Mitt.  Mus.  Ham- 
burg, Bd.  XIII,  pp.  49^71.    Hamburg. 

Description  of  several  new  species  of  Holothurioidea,  Jour.  Acad. 
Nat.  Sci.  Phila.  Vol.  IV,  pp.  155-163. 

Beitrage  zur  Kenntniss  der  Holothurien.    Arb.  Zool.  Zoot.  Inst. 

Bd.  II,  Heft  2,  pp.  77-118,  pis.  VI,  VII.    Wurzburg. 

Bevision    der   Mertens-Brandt'schen   Holothurien.     Zeit.    Wiss. 

Zool.  Vol.  XXXV,  pp.  575-599. 

Ueber  eine  lebendige  gebaerende  Synaptide  und  zwei  andere 

neue  Holothurien-arten  der  Brazilianischer  Kuste.    Arch.  Biol. 

T.  II,  pp.  41-58,  pi.  in.    Liege. 

Verzeichniss  der  Holothurien  des  Kieler  Mus.  Bericht.     Oberh. 

Gesell.    Nat.  Heilk,  Bd.  XXII,  pp.  155-176.    Giessen. 

Arktische  und  Subarktische  Holothurien.    Fauna  Arctica.     Bd. 

I,  lief.  1,  pp.  135-178.    Jena. 

.  V. 

Contribution  a  l'ltude  des  Holothuries  de  PAtlantique  du  Nord 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

(Golfe  de  Gascogne,  Isles  Azores).    Resul.  Comp.  Sci.  Prince  de 
Monaco,  Fasc.  VI,  pp.  1-22,  pis.  1-2.    Monaco. 

Mitsukuri 

1912       Actinopodous  Holothurians.    Jour.  Coll.  Sci.  Tokyo,  Vol.  XXIX, 
Art.  2,  pp.  284,  pis.  I- VIII. 

Miiller  J. 

1850  Anatomische  Studien  ueber  die  Echinodermen.     Miillers  Arch, 
pp.  129-147,  225-233. 

1854      Ueber  den  Bau  der  Echinodermen.    Abh.  Berl.  Akad.  Wiss.  aus 
d.  Jahre  1853,  pp.  96,  pis.  9.     Berlin. 
Oestergren  H. 

1896       Zur  Kenntniss  der  Subfamilie  der   Synallactinee.       Festschrift 
W.  Lilljeborg,  pp.  345-369,  pi.  XVIII.    Upsala. 
Perrier  R. 

1903       Holothuries.     Exped.  du  Travailleur  et  Talisman,  pp.  273-552, 
pis.  I-XI.    Paris. 
Pourtales  L.  F. 

1851  On  the  Holothuridse  of  the  Atlantic  Coast  of  the  United  States. 
Proc.  Amer.  Ass.  Adv.  Sci.  Fifth  Meeting,  pp.  8-16,  Washington. 

Eathbun  R. 

1879      List  of  the  Brazilian  Eehinoderms,  etc.     Trans.  Connect.  Acad. 
Vol.  XV,  pt.  1,  pp.  139-158. 
Selenka  E. 

1867  Beitrage  zur  Anatomie  u.  Systematik  d.  Holothurien,  Zeit.    Wiss. 
Zool.    Bd.  XVII,  pp.  291-374,  pis.  XVII-XX.    Leipzig. 

Semper  C. 

1868  Reisen  im  Archipel  der  Philippinen.    Theil  II.  Wiss.  Res.  Bd.  1, 
Holothurien,  pp.  228,  pis.  I- XL.     Leipzig. 

Siuiter  C.  Ph. 

1910       Westindische    Holothurien,    Erg.    Zool.    Forschungsreise    nach 
Westindien  von  W.  Kukenthal  u.  R.  Hartmeyer.  Zool.  Jahrb.  f. 
Anat.  u.  Syst.,  Suppl.  XI,  Heft  2,  pp.  331-341.     Jena. 
Stimpson  W. 

1860       Zoological   Notices  on  the   Genus   Synapta  by  Woodward  and 
Barrett.  Amer.  Jour.  Sci.  Vol.  XXIX,  p.  134.     New  Haven. 
Thed  H. 

1886a     Report  on  the  Holothurioidea.     Pt.  II.  Rep.  Sci.  Res.  H.M.S. 
"Challenger,"   Zool.   Vol.   XIV,  Pt.    39,   pp.   290,   pis.   I-XVL 
London. 
1886b     Report   on   the   Holothurioidea.     Bull.   Mus.   Comp.   Zool.   Vol. 
XIII,  pp.  1-21,  pi.  1.     Cambridge,  Mass. 
Verrill  A. 

1868  Notice  of  the  corals  and  eehinoderms  collected  by  Prof.  C.  F. 
Hartt  at  the  Abrolhos  Reefs,  Province  of  Bahia,  Brazil,  1867. 
Trans.  Conn.  Acad.  Vol.  I,  pp.  351-376.  New  Haven. 
1901  Additions  to  the  Fauna  of  Bermuda.  Trans.  Connect.  Acad. 
Sci.,  Vol.  XI,  pp.  583-587. 
1904-07  The  Bermuda  Islands.  Geology,  pp.  144-145,  320-322.  Text 
ng.  37-39,  171-173,  Trans.  Connect.  Acad.  Sci.  Vol.  XII. 


HOLOTHURIANS  OP  BAEBADOS  AND  ANTIGUA   31 
EXPLANATION  OF  PLATES 

PLATE  I 

Holothuria  surinamensis  Ludwig,  x670 

la  Disk  of  table  from  very  young  specimen 

lb  Lateral  view  of  table  from  very  young  specimen 

lc  Top  of  spire  seen  from  above,  of  old  specimen 

ld-e  Tables  with  completely  absorbed  disk,  lateral  view 

If  Half  of  rod  from  skin  of  old  specimen 

lg  Hod  from  near  the  end  of  pedicel  of  old  animal 

Mesothuria  verrilli  Theel 

2a       Lateral  view  of  table 

2b      Bisk  of  table  from  above 

PLATE  II 
Holothuria  fossor  n.sp.,  x670 

la-b    Supporting  rods  from  pedicel 

lc       Flattened  button  from  ventral  side 

Id       Knobbed  button  from  ventral  side 

le       Small,  relatively  simple  table  from  pedicel 

If       Disk  of  very  simple  small  table  from  pedicel 

lg-h    Buttons  from  dorsal  side 

li-j     Supporting  rods  from  papilla 

PLATE  III 
Thy  one  surinamensis  Semper,  x670  (except  lc  and  2a) 

la  Knobbed  button 

lb-c  Baskets,  seen  from  above 

Id  Baskets,  lateral  view 

le        Supporting  rods  from  pedicel,  x270 

Thyone  suspecta  Ludwig 

2a       Supporting  rods  from  pedicel,  x270 
2b-c    Baskets,  lateral  view 
2d-e    Buttons 


PLATE  I 


-v 


A: 


PLATE  III 


LEPIDOPTERA 

Collected  by  the  Barbados- Antigua  Expedition  from  the 
University  of  Iowa 

A.  W.  Lindsey 
Denison  University 

The  delicacy  of  Lepidoptera  necessitates  special  care  in  the  collect- 
ing and  handling  of  these  insects  which  is  not  at  all  compatible  with 
extensive  work  on  other  orders.  It  is  therefore  not  surprising  that 
Dr.  Stoner's  catch  of  butterflies  and  moths,  submitted  to  me,  is 
small,  nor  that  it  is  made  up  mostly  of  species  common  in  the  islands. 
More  surprising,  indeed,  is  the  fact  that  this  small  lot  includes  two 
undescribed  species,  a  Syntomid  moth,  which  I  am  pleased  to  name 
in  the  following  pages  in  honor  of  Dr.  Stoner,  and  a  Cossid. 

The  specimens  included  in  the  lot  are  listed  below.  With  few 
exceptions  the  species  represented  occur  also  in  the  southern  part 
of  our  own  continent,  while  some  are  found  even  farther  north. 

Pieridae 

Pieris  vaiei  Bdv.  Antigua,  June  24,  1  3  ,  5  9  ;  July  1,  4  3  ,  2  $  . 
Catopsilia  eubule  Linn.  Antigua,  June  24,  1  $  ;  July  1,  1  $  ;  July  6, 

63,1$. 
Ewrema  euterpe  Men.  Antigua,  June  22,  1  3  ;  23,  1  3  ;  24,  1  3  ,  3  $  ; 

July  1  and  6,  6  3,1$.    All  females  show  a  marked  tendency  to 

albinism. 

Nymphalidae 
Helieonius  charithania  Linn.  Antigua,  June  22,  1  3  . 
Dione  vanillw  Linn.  Bridgetown,  Barbados,  May  22,  1  3  ,  1  $  ;  June 

11,  1  3  ,  1  $  .    Barbados,  May,  1  $  ;  June  6,  1  3  .    Antigua,  June 

22,  2  3  ;  June  24,  1  3  . 
Junonia  genoveva  Cram.  Bridgetown,  Barbados,  May  16,  2  $  ;  May 

22,  2  $  .    Barbados,  June  3,  1  3  -    Antigua,  June  22  and  24,  1  3 

each. 
Phyciodes  anocaona  H.-S.  Antigua,  June  24, 1  $  . 

Lycsenidse 

Lyccena  hanno  Stoll.  Antigua,  June  24,  1  3  ,  1  $  . 
Thecla  acis  Dru.  Antigua,  June  24,  1  $ . 

33 


34  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

Hesperiidae 

Eudamus  proteus  Linn.  Antigua,  July  6  and  8,  1  $  each. 
Brachycoryne  areas  Dru.  Antigua,  June  22,  1  $  . 

Sphingidae 

Protoparce  rustica  Fab.  Barbados,  June,  1  $  . 
Xyloph&ms  pluto  Fab.  Antigua,  June  24,  1  $  . 


Horama  stoneri  n.  sp. 


Syntomidse 


Expanse  of  type  34  mm. 

$ .  Head  black  with  a  bright  ochre  spot  between  antennae  and  two  before 
eyes.  Palpi  also  bright  ochre.  Antennae  black  with  ochreous  tips.  Collar 
with  whitish  ochreous  spots  at  middle  and  sides,  and  an  elongated  spot,  almost 
fulvous,  below  the  latter.  Patagia  black  with  a  bright  ochre  line  near  upper 
margin.  Thorax  black  above  with  two  bright  ochre  spots  on  mesonotum  and 
two  on  metanotum,  and  a  small  pure  white  spot  at  humerus  of  each  primary. 
Below  with  a  white  spot  above  coxa  of  each  leg,  the  last  four  large  but  the 
first  two  small.  Coxae  with  a  bright  ochreous  patch  on  each.  Tibiae  and  tarsi 
mostly  ochreous.  Tips  of  hind  tibiae  and  all  of  femora  brownish.  First  ab- 
dominal segment  strongly  bullate  on  the  sides.  Anterior  half  of  tergite  of  this 
segment  silky  white,  separated  by  a  brownish  line  from  the  bright  ochreous 
posterior  part.  The  ochreous  portion  extends  almost  completely  over  the  bullae. 
Remaining  segments  brown  with  slender  terminal  lines,  ochreous  on  all  but  the 
first  two  where  they  are  pure  white  ventrad  and  pale  above. 

The  primaries  approach  cinnamon  brown  but  are  duller  in  shade.  They  are 
brightest  at  the  base.  Secondaries  bright  ochreous  in  the  anal  area,  blending 
into  buff  at  the  costal  margin  and  brown  at  the  apex.  The  under  surface  of 
the  primaries  is  almost  evenly  ochreous,  of  the  secondaries  a  similar  but 
brighter  color. 

Holotype  $  ,  Antigua,  June  24.  Two  other  females  were  taken 
June  21  and  there  is  a  male  from  the  same  island  in  the  National 
Museum.  This  undoubtedly  belongs  to  the  same  species,  but  since 
it  is  without  an  abdomen  it  is  not  being  included  in,  the  type  series. 

Arctiidae 

Utetheisa  ornatrix  Linn.  Barbados,  May,  1  $  ;  May  16-18,  20  speci- 
mens of  both  sexes :  June  3,2  $  ;  June  8,  2  £  ,  1  $  ,  and  one  broken 
specimen. 

Noctuidse 

Melipotis  contorta  Gn.  Antigua,  June  28,  1  9  . 

Melipotis  famelica  Gn.  Antigua,  June  24,  3  $  ;  July  1,  1  $ . 

Hyblcea  puera  Cram.  Antigua,  June  22,  1  $  . 

Aletia  argillacea  Hbn.  Barbados,  May  16,  1  $  . 


LEPIDOPTERA  OP  BARBADOS  AND  ANTIGUA       35 

Cossidse 

Psychonoctua  lillianw,  n.  sp. 

Expanse  of  type  48  mm. 

$  .  Vestiture  qf  the  body  and  head  a  mixture  of  chalky  white  and  dull 
brown  scales,  giving  the  insect  a  hoary  brownish-gray  color. 

The  primaries  are  similar  to  the  body,  but  with  more  brown  scales  grouped 
together  in  some  parts.  These  form  a  brown  basal  patch  with  an  oblique  out- 
er margin  beginning  about  one  third  from  base  of  wing  on  costa  and  running 
almost  to  base  as  it  approaches  the  inner  margin.  In  it  there  is  a  short  long- 
itudinal black  dash  just  behind  cell.  In  the  type  this  has  two  short  projec- 
tions on  the  costal  side  and  one  between  them  on  the  opposite  side.  About 
one  third  from  apex  on  costa  a  brown  shade  arises  which  runs  to  inner  margin 
parallel  with  the  outer  limit  of  the  basal  shade.  This  contains  a  blackish 
crescent  at  end  of  cell.  The  median  pale  area  thus  enclosed  is  whiter  than  the 
rest  of  the  wing.  Terminal  area  slightly  clouded  with  brown.  Entire  wing 
marked  with  transverse  brown  strigge.  Fringes  whitish  with  brown  tufts  at 
ends  of  veins. 

The  secondaries  are  more  evenly  colored.  They  are  brownish  white  with  a 
few  dark  strigse  in  the  outer  margin  toward  the  anal  angle.  Fringes  as  in 
primaries. 
Oh  the  outer  surface  the  primaries  are  clouded  with  gray-brown,  paler  be- 
hind cell,  slightly  paler  and  strigate  in  terminal  third,  and  faintly  barred 
with  white  in  basal  two-thirds  of  the  extreme  costal  area.  Secondaries  as 
above. 

Holotype  $  ,  Antigua,  July  1,  collected  by  Mrs.  Stoner  for  whom 
the  species  is  named.  I  am  indebted  to  Dr.  Schaus  for  comparing 
the  type  with  the  material  in  the  National  Museum. 

Through  the  kindness  of  Dr.  Stoner  the  types  of  H.  sfoneri  and 
P.  MlliaiKB  have  been  placed  in  the  U.  S.  National  Museum. 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 

Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  8 


PAPERS  ON  GEOLOGY 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY,  IOWA 


CONTENTS 


Additional  Cystoids  and  Crinoids  from  the  Maquoketa 

Shale  of  Iowa  A.  0.  Thomas  and  H.  S.  Ladd 

A  Theory  of  Origin  of  Some  Limestone  Masses  and 

Septaria  A.  L.  Lugn 

Methods  of  Collecting  Sediment  Samples  from  the 

Mississippi  River  A.  L.  Lugn 


ADDITIONAL  CYSTOIDS  AND  CRINOIDS  FROM 
THE  MAQUOKETA  SHALE  OF  IOWA 

A.  0.  Thomas  and  H.  S.  Ladd 

(PLATES  I-VI) 

An  excellent  paper  has  recently  appeared  on  the  echinoderms  of 
the  Maquoketa  of  Iowa.1  It  was  based  on  collections  made  several 
years  ago  and  found  almost  wholly  within  Fayette  county.  Dur- 
ing the  past  two  or  three  years  the  junior  author  has  made  an  ex- 
tensive study  of  the  entire  Maquoketa  terrane  in  Iowa  and  in  the 
course  of  that  investigation  has  made  large  collections  of  fossils  at 
many  horizons  and  localities.  The  echinodermal  material  collected 
presents  not  only  new  forms,  but  new  facts  about  old  forms  and 
new  locality  records  for  others.  Most  of  the  new  material  described 
was  found  in  the  cherty  and  dolomitic  beds  of  the  Fort  Atkinson 
limestone  member  (Middle  Maquoketa).  This  member  was  found 
best  exposed  at  its  type  locality,  the  quarry  at  the  old  blockhouse 
near  the  town  of  Fort  Atkinson  in  Winneshiek  county.  Here  a 
large  amount  of  recently  quarried  rock  yielded  abundant  echino- 
dermal remains.  Many  fragmentary  specimens  of  undetermined 
relationships  were  found.  These  assure  the  future  student  that  the 
field  is  but  partly  worked. 

The  most  interesting  discovery  is  a  heterostelean  cystid  which  be- 
longs to  a  little  known  race.  Its  relatives  are  largely  European.  It 
is  placed  in  a  new  genus,  Iowacystis,  and  it  does  not  fit  well  into 
any  of  the  defined  families.  A  heterocrinid  exhibiting  thick  and  un- 
usually large  proximal  stem  columnals  proves  to  be  new  and  a  Por- 
ocrinus  which  has  undergone  much  reduction  of  its  fold  areas  is 
described  and  illustrated. 

The  writers  wish  to  acknowledge  the  valuable  suggestions  of  Drs. 
Frank  Springer  and  August  F.  Foerste  to  whom  photographs  were 
submitted  and  whose  opinions  were  solicited  concerning  the  new 
Ectenocrinus  and  Iowacystis  respectively.  The  papers  of  Dr.  F.  A. 
Bather  have  been  freely  consulted  in  the  study. 


i  Slocom,  A.  W.,  and  Foerste,  August  F.,  New  Echinoderms  from  the  Ma- 
quoketa Beds  of  Fayette  County,  Iowa,  Iowa  Geol.  Surv.,  vol.  XXIX,  pp.  315- 
384,  1924. 


6  IOWA  STUDIES  IN  NATURAL  HISTOEY 

CYSTOIDBA  von  Buch 

Amphoridea  Haeckel  (pars) 

Anomalocystictee  Meek 

Iowacystis  gen.  nov. 

Theca  triangular,  compressed,  presumably  concavo-convex,  sur- 
rounded by  a  border  of  marginal  plates  which  are  extended  to  form 
a  part  of  the  surface  on  each  side.  A  single  process,  or  arm,  com- 
posed of  many  small  ossicles  arises  from  a  special  group  of  circum- 
oral  plates  near  the  apex  of  the  convex  or  oral  side.  Body  plates  of 
the  oral  side  smaller  and  more  numerous  than  those  of  the  opposite 
or  posterior  side  where  they  display  bilateral  symmetry.  Anal  pore 
in  sagittal  plane  at  the  lower  left  corner  of  the  oral  side. 

Stem  longer  than  the  theca,  tapering,  composed  of  vertical  rows 
of  ossicles  in  which  there  is  a  short  proximal  series  of  thin  colum- 
nals  changing  abruptly  to  a  distal  series  of  alternating  polygonal 
pieces  most  of  which  are  longer  than  wide. 

This  genus  exhibits  a  group  of  characters  which  places  it  close  to 
the  family  Anomalocystidas  and  to  which  it  is  provisionally  referred. 
However,  the  triangular  outline  of  the  theca,  its  stem  characters, 
plate  markings  and  single  oral  process  located  outside  the  sagittal 
plane  are  foreign  to  that  family.  Foerste  suggests  further  relation- 
ship to  the  Mitrocystidse  or  Lagynocystidse.  The  genus  may  even- 
tually be  relegated  to  a  new  family. 

Iowacystis  sagittaria  gen.  nov.  et  sp.  nov. 
Plates  I,  figs.  1-5 ;  II,  fig.  1 ;  IV,  figs.  1-6 ;  V,  figs.  1,2. 

The  description  is  based  on  four  specimens  and  a  number  of  stem 
fragments.  For  convenience  the  four  thecas  may  be  referred  to  as 
a,  b,  cy  and  d.  Specimen  a  is  attached  by  its  concave  (posterior) 
side  to  a  matrix  of  shaly  dolomitic  limestone.  It  is  the  largest  and 
most  nearly  complete.  The  exposed  convex  (oral)  side  has  been 
crushed  in  and  the  basal  and  lower  marginals  are  wanting  at  one 
corner  and  disarranged  at  the  other.  Specimen  b  is  free.  Several 
fractures  tend  somewhat  to  destroy  the  identity  of  the  sutures  and 
the  plates  of  the  two  sides  have  been  pressed  together  obscuring  the 
original  coneavo-convexity ;  the  proximal  part  of  the  stem  is  pre- 
served and  the  thecal  apertures  near  the  apex  are  well  shown. 
Specimen  c  is  the  smallest.  It  was  freed  from  the  matrix  with  some 
difficulty.    Its  posterior  side  is  well  preserved  and  shows  the  bilateral 


MAQUOKETA  CYSTOIDS  AND  CKINOIDS      7 

symmetry  and  plate  markings;  the  apical  region  is  distorted.  Speci- 
men d  is  also  free,  of  normal  size,  has  lost  some  of  the  body  plates 
but  retains  a  full  centimeter  of  the  stem.  It  preserves  best  the 
plates  of  the  anal  pore. 

Outline  of  the  theca  triangular  or  sagittate.  Base  arched  gently 
upward  and  bearing  centrally  a  re-entrant  depression  for  the  recep- 
tion of  the  stem.  Edges  nearly  straight,  each  meeting  the  base  at  an 
angle  of  approximately  64  degrees ;  basal  corners  rounded.  Margin- 
als thick  and  heavy,  the  lateral  ones  elongate ;  they  are  nine  in  num- 
ber and  form  a  frame  encircling  the  theca  except  where  it  unites 
with  the  stem.  There  are  three  marginals  on  each  side,  the  lower  of 
which  forms  the  corner ;  between  the  stem  and  the  lower  marginal 
is  a  single  elongate  basal  marginal.  The  ninth  plate  is  the  apical 
marginal  and  it  rests  in  an  angle  between  the  contiguous  apical  ends 
of  the  superior  pair  of  marginals.  The  peripheral  faces  of  the 
marginals  are  conspicuously  decorated  by  an  intricate  system  of 
ridges  and  grooves.  The  median  marginals  and  to  a  certain  extent 
those  above  and  below  them  are  constricted  at  their  mid-length.  In 
the  broad  depression  thus  formed  lies  a  narrow  transverse  ridge 
which  is  a  slender  continuation  of  the  smoother  and  less  decorated 
posterior  surface  of  the  plate.  Each  marginal  forms  a  part  of  the 
surface  on  the  oral  and  on  the  posterior  thecal  sides  but  is  asym- 
metrical in  that  it  extends  farther  over  the  posterior  side  than  over 
the  oral.  The  apical  plate  is  pentagonal  in  outline  and  protrudes 
beyond  the  remainder  of  the  theca ;  the  surface  of  its  posterior  face 
is  flat  and  flush  with  the  faces  of  the  contiguous  superior  marginals ; 
a  smooth  linguif orm  elevated  band  forms  its  extreme  apical  part  and 
extends  from  the  posterior  surface,  of  which  it  is  a  continuation, 
down  to  the  apical  edge  of  plate  G;  a  distinct  groove  flanks  each  side 
of  this  apical  band,  for  the  reception  of  which  it  is  slightly  undercut. 

The  somatic  or  body  plates  are  fewer  in  number  and  larger  on  the 
posterior  side  where  they  achieve  almost  perfect  bilateral  symmetry 
(see  Plate  V,  fig.  2).  They  are  seven  in  number  and  are  arranged 
as  follows :  one,  the  largest,  is  hexagonal  in  shape,  and  situated  near 
the  center ;  four  others,  smaller  in  size  and  irregularly  polygonal  in 
shape,  are  arranged  in  an  arch  whose  ends  rest  on  the  basal  margin- 
als. The  sixth  is  median  in  position  and  just  above  the  stem.  It  is 
seven-sided,  curved  below  and  its  lower  border  is  thickened  by  a 
heavy  ridge  of  which  there  is  a  lateral  continuation  in  the  form  of  a 
less  prominent  ridge  on  the  adjoining  basal  marginals.    This  plate 


8  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

and  its  opponent  on  the  oral  side  lie  between  the  proximal  ends  of 
the  basal  marginals ;  all  f  our  apparently  contribute  to  the  area  of  the 
stem  facet.  The  seventh  is  also  polygonal  and  lies  between  the  right 
lower  and  basal  marginals;  proximally  it  abuts  against  the  lower 
right  corner  of  the  four-plate  arch  and  distally  it  partially  supports 
the  anal  pore.  This  small  plate  is  the  chief  disturbing  element  in 
the  symmetry  of  the  posterior  face.  Its  position  and  relations  are 
well  shown  on  specimens  b  and  d. 

On  the  oral  side  the  somatic  plates  are  fully  forty  in  number. 
Their  exact  arrangement  on  the  lower  half  of  the  theca  is  uncertain 
since  on  each  of  the  specimens  at  hand  a  few  of  the  plates  are  either 
lost  or  misplaced.  On  specimens  a  and  d  the  median  plate  just 
above  the  stem  appears  to  be  in  place  and  is  much  smaller  than  the 
opposite  plate  as  seen  on  the  posterior  side  of  6  and  d;  moreover,  it 
does  not  bear  a  ridge  along  its  lower  border  but  a  groove,  thought  to 
be  the  edge  of  the  stem  facet,  is  visible  beneath  its  lower  edge.  The 
other  plates  of  this  side  except  those  of  the  upper  part  are  small, 
polygonal,  and  without  symmetry. 

Near  the  apical  end  of  the  oral  side  is  a  group  of  three  special 
plates,  two  large  and  one  small.  Close  to  the  right  hand  edge  of  the 
theca  and  on  a  level  with  the  superior  marginals  the  common  edges 
of  the  three  plates  form  an  elongate  groove  which  opens  below  into 
the  theca.  Out  of  this  groove  and  over  the  opening  arises  a  process 
composed  of  several  small  movable  plates  apparently  in  two  rows 
and  separated  along  their  outer  side  to  form  a  longitudinal  slit.  The 
total  length  of  this  arm-like  appendage  is  unknown  but  on  b  the 
portion  preserved  extends  beyond  plate  A.M.  (see  Plates  I,  figs.  4,  5 ; 
V,  fig.  1).  The  right  hand  and  lowermost  plate  of  the  three,  here 
designated  0,  is  polygonal  and  elevated  into  a  thick  lip  around  the 
lower  edge  of  the  oral  aperture.  Above  it  and  to  the  left  is  an  equal- 
ly large  irregular  plate,  here  designated  6r.  It  is  separated  from  0 
and  the  two  small  somatic  plates  by  simple  and  nearly  straight 
sutures,  but  the  line  of  its  contact  with  the  left  superior  marginal  is 
much  crenulated  to  fit  the  ridges  and  depressions  of  the  latter 's  sur- 
face. The  plate  is  heavy  and  thick  and  the  adapical  part  of  its  sur- 
face is  elevated  into  a  pointed  cone  directed  outward  and  upward ; 
in  the  apex  of  the  cone  is  a  small  depression,  evidently  a  pore, 
thought  to  be  the  gonopore.  The  small  plate,  here  called  Y,  lies  be- 
tween the  right  superior  marginal  and  plates  A.M.,  G  and  0;  viewed 


MAQUOKETA  CYSTOIDS  AND  CRINOIDS      9 

from  the  right  it  is  oblong  quadrangular  in  shape  and  it  fits  closely 
about  the  base  of  the  brachial  process. 

The  anal  pore  appears  to  be  located  close  to  the  sagittal  or  margin- 
al plane.  It  is  at  the  lower  left  hand  corner  as  seen  from  the  oral 
side  and  is  thus  located  as  far  as  possible  from  the  intake.2  The 
opening  is  surrounded  by  a  ring  of  small  polygonal,  mostly  quad- 
rangular, plates  distal  to  which  are  two  larger  plates  now  closely 
appressed.  The  crushed  condition  of  the  specimen  makes  restora- 
tion of  the  pyramid  difficult  and  it  is  believed  that  one  or  more 
plates  have  been  lost  from  its  apical  part. 

The  stem  is  composed  of  two  series  of  columnals,  a  proximal  which 
is  made  up  of  pairs  of  ossicles  which  are  much  wider  than  long,  and 
a  distal  series  of  alternating  columnals  most  of  which  are  longer 
than  wide. 

The  thin  proximal  ossicles,  although  somewhat  separated  in  all 
the  specimens,  appear  to  have  fitted  into  each  other  much  as  does  a 
number  of  nested  pans  with  the  extended  slightly  nodose  peripheral 
edge  proximal  in  position.  The  most  distal  ossicle  of  this  series,  as 
seen  on  a,  is  little  more  than  a  ring  or  band  fitting  around  the  taper- 
ing proximal  extension  of  the  first  columnal  of  the  larger  series.  On 
the  posterior  side  (specimen  b)  where  the  basal  re-entrant  is  deeper 
seven  pairs  of  ossicles  are  visible ;  there  are  but  five  in  view  on  the 
oral  side.  The  alternating  series  of  columnals,  as  seen  on  a,  tapers 
gradually  and  ends  in  a  number  of  disorganized  small  pieces  which 
may  or  may  not  have  belonged  to  the  stem.  In  a  there  are  seven 
columnals  in  place  on  the  right  and  eight  on  the  left.  Each  columnal 
on  the  right  or  left  is  in  contact  with  the  two  on  the  opposite  side. 
Proceeding  distally  the  length  of  the  contact  border  with  the  oppo- 
site upper  columnal  becomes  successively  longer  for  the  left  hand 
row  and  successively  shorter  for  the  right  hand  row.  The  stem  at 
any  point  is  flattened  oval  in  cross-section.  The  regularity  of  the 
columnals  as  exhibited  by  a  is  much  less  apparent  on  some  stem  frag- 
ments collected  at  the  type  locality  (Plate  IV,  figs.  3-6) .  In  these,  at 
intervals,  small,  more  or  less  equidimensional  ossicles  occur  singly  or 
in  groups.  On  the  posterior  side  of  one  specimen  (fig.  6)  there  is  a 
tendency  to  have  three  ossicles  at  the  same  level  in  the  stem. 

The  markings  of  the  plates  of  the  posterior  side  consist  of  a  num- 
ber of  scattered  low  nodes  which  exhibit  no  definite  arrangement  ex- 


2  See  Bather,  F.  A.,  Paleont.  Zeitschr.,  Bd.  VII,  Heft  1,  p.  6,  1925. 


10 


IOWA  STUDIES  IN  NATURAL  HISTOEY 


cept  on  plate  A.M.  and  on  the  flanks  of  the  superior  marginals  where 
they  attain  a  more  or  less  linear  distribution  parallel  to  the  sides  of 
the  theca.  The  mosaic  of  small  polygonal  plates  of  the  oral  side  is 
marked  by  an  abundance  of  nodes  and  wavy  ridges  which  have  a 
more  or  less  radial  arrangement.  The  median  plate  just  above  the 
stem  partakes  of  the  same  general  pattern.  Plates  0  and  G  have 
especially  strong  ridges  which  are  notably  prominent  on  the  right 
half  of  Cr  where  they  are  normal  to  the  suture  between  G  and  0.  On 
the  flanks  of  the  apically  perforated  cone  on  G  are  a  number  of  tiny 
pustules  which  have  the  appearance  of  being  perforated ;  their  pur- 
pose, if  functional,  is  unknown.  The  elaborate  system  of  grooves  and 
ridges  on  the  marginals  and  their  evident  continuity  from  plate  to 
plate  along  the  periphery  of  the  theca  suggest  that  they  may  have 
had  a  part  to  play  in  the  economy  of  the  animal  other  than  decora- 
tion. The  larger  columnals  of  the  stem  are  coarsely  granular  prox- 
imally  but  distally  this  disappears  to  the  extent  that  the  lowermost 
columnals  are  nearly  smooth. 
Measurements  of  the  four  cotypes  are : 

abed 

Total  length  of  theca ~ 22.0  mm.     22.0  mm.     13.0  mm.     22.7  mm. 

Width  at  base _ 21.0  mm.     20.0  mm.     11.5  mm.     20.5  mm. 

Length   of   median   marginal— 7.6  mm.       8.2  mm.       5.0  mm.       7.9  mm. 

Length  of  plate  O 4.5  mm.       4.5  mm 

Length  of  plate   G ~ .....  6.0  mm.       6.0  mm 5.5  mm. 

Stem,  total  length3 34.0  mm 

Stem,  oral  side  of 

proximal  series  . 6.0  mm.       7.0  mm 6.6  mm. 

Stem,  posterior  side  of 

proximal  series  - 8.1  mm 8.4  mm. 

Occurrence :  In  the  somewhat  shaly  and  dolomitic  beds  of  the 
Fort  Atkinson  limestone  (Middle  Maquoketa)  at  the  old  Fort  Atkin- 
son quarry,  Winneshiek  county,  Iowa,  Collected  by  A.  O.  Thomas 
and  H.  S.  Ladd.  The  four  specimens  are  regarded  as  cotypes  and 
are  in  the  paleontological  collections  at  the  University  of  Iowa. 
Specimens  a,  h,  c,  and  d  are  numbered  respectively  3525,  3526,  3527, 
and  3528.    The  stem  fragments  are  entered  as  number  3529. 

Undetermined  cystid  plate,  A. 
Plate  IV,  fig.  7. 
A  nearly  perfect  rhomb-bearing  plate  of  callocystine  characters 
was  found  in  the  highly  f ossilif erous  zone  near  the  top  of  the  Ma- 

3  Stem  measurements  are  of  doubtful  value  since  the  plates  of  the  proximal 
series  are  somewhat  separated  in  the  material  at  hand. 


MAQUOKETA  CYSTOIDS  AND  CRINOIDS  11 

quoketa  formation.  The  plate  is  small  (7.2  x  6.  mm.),  is  five-sided, 
gently  curved  in  the  direction  of  its  greatest  dimension,  and  decorat- 
ed with  vermicular  sculpturing.  It  bears  a  deep-set  half  rhomb 
which  is  curved  or  somewhat  boomerang-shaped.  The  border  of  the 
depression  is  sharply  elevated  and  the  bordering  ridge  is  higher  on 
the  outer  than  on  the  inner  edge  of  the  pit.  There  are  twenty-two 
dichopores,  nine  in  the  shorter  and  thirteen  in  the  longer  limb  of  the 
pit. 

Collected  by  A.  0.  Thomas  from  the  Maquoketa  shale  in  Sec.  32, 
Fairfield  township,  Jackson  county,  Iowa,  where  it  is  associated  with 
Cornulites  sterlingensis,  Plectambonites  sericeus,  Zygospvra  cf. 
modesta,  Calymene  gracilis,  and  others.  The  specimen  is  number 
3530. 

Miscellaneous  cystid  plates,  B,  C,  and  D. 
Plate  III,  figs.  5,  8,  9. 

The  first  of  these  is  a  large  plate  from  the  theca  of  some  species  of 
Pleurocystites  similar  to  P.  beckeri  Foerste.  It  preserves  well  the 
characteristic  markings.  Maquoketa  shale,  upper  f  ossilif  erous  zone, 
Stockton,  Illinois.    Collected  by  H.  S.  Ladd. 

Specimen  C  is  a  thin  six-sided  plate  marked  by  twelve  heavy 
ridges  which  radiate  from  the  center  of  the  plate,  one  to  each  angle 
and  one  to  the  center  of  each  edge.  Between  the  radial  lines  are 
fine  nodes  and  vermicular  ridges.  The  inner  face  is  smooth.  It  evi- 
dently corresponds  to  thecal  plate  15  or  16  of  Pleurocystites  beckeri 
Fberste.  Collected  from  the  f  ossilif  erous  zone  of  the  upper  Ma- 
quoketa at  Sec.  32,  Fairfield  township,  Jackson  county,  Iowa,  by  A. 
O.  Thomas. 

Specimen  D  is  a  plate  from  the  basal  circlet  of  Pleurocystites 
clermontensis  Foerste.  The  lower  or  basal  end  is  thick  and  flat  and 
makes  up  a  part  of  the  area  for  the  attachment  of  the  stem.  A  few 
strong  ridges  radiate  upward  from  its  lower  margin.  It  appears  to 
correspond  with  thecal  plate  4  according  to  Bather's  system  of  num- 
bering. Collected  by  H.  S.  Ladd ;  Fort  Atkinson  member,  Fort  At- 
kinson, Iowa. 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

CRINOIDEA 

Inadunata 

fistulata 
Heterocrinidae 

Ectenocrinus  elongatus  sp.  nov. 
Plate  II,  figs.  3-8 ;  V,  figs.  3,  4. 

This  species  is  based  on  five  specimens,  f our  of  them  free  and  one 
attached  to  a  chip  of  rock.  They  are  here  referred  to  as  a,  b,  c,  d 
and  e.  The  first  three  preserve  the  basals,  radials  and  part  of  the 
brachials,  d  preserves  the  basals  and  part  of  the  radials,  e  is  repre- 
sented by  a  number  of  plates  all  more  or  less  jumbled.  All  five  pre- 
serve large  proximal  stem  segments. 

Calyx  small,  round,  elongate,  expanding  gradually  to  the  top  of 
the  radials  just  above  which  it  becomes  slightly  constricted.  Below 
the  basals  are  two  to  five  round  heavy  columnals  which  become  suc- 
cessively narrower  and  shorter  distally  until  they  grade  into  the 
normal  stem.  This  unusual  feature  gives  the  crinoid  a  very  elongate 
appearance  and  a  proportionally  much  wider  diameter  through  the 
basals  than  is  usual  in  heterocrinids. 

Basals  five,  pentagonal,  sides  sub-parallel ;  the  upper  sutures  which 
are  in  contact  with  the  inferradials  are  longer  than  those  in  contact 
with  the  base  of  the  undivided  radials  thus  making  four  of  the 
basals  asymmetrical  while  the  fifth  which  supports  the  inferradials 
of  the  right  posterior  and  right  anterior  rays  is  a  perfect  pentagon. 
Radials  five ;  the  right  posterior,  the  right  anterior  and  the  left  an- 
terior are  compound;  the  superradials  are  larger  than  the  infer- 
radials and  in  direct  line  over  them.  The  inferradials  rest  point 
downward  between  the  basals ;  they  are  pentagonal  in  shape  except 
the  right  anterior  which  is  hexagonal  due  to  a  small  suture  at  its 
upper  left  hand  corner  where  it  is  in  contact  with  the  right  posterior 
superradial.  The  right  anterior  and  left  posterior  superradials  are 
quadrangular,  a  little  wider  above  than  below ;  the  right  posterior  is 
hexagonal  due  to  truncation  of  opposite  corners,  one  to  receive  the 
first  anal  and  the  other  to  make  contact  with  the  right  anterior  in- 
ferradial  as  mentioned  above.  The  suture  dividing  each  compound 
radial  is  curved  gently  downwards.  The  two  undivided  radials  are 
the  largest  plates  in  the  calyx,  the  anterior  one  is  heptagonal  and 
the  left  posterior  is  octagonal,  the  extra  suture  in  the  latter  being 


MAQUOKETA  OYSTOIDS  AND  CRINOIDS  13 

due  to  the  position  of  the  anal.  Primibraehs  two,  the  first  quad- 
rangular, narrowed  distally  and  transversely  rounded  just  above  its 
mid-length ;  the  second  shorter,  pentangular,  wider  than  long  and 
inclined  outward  distally.  The  transverse  suture  at  the  base  of  the 
first  primibrach  is  wide  and  located  in  a  deep  groove  indicating  con- 
siderable freedom  of  articulation  at  this  point  above  which  all  plates 
appear  to  be  movable.  Plates  beyond  these  unknown  except  a  few 
displaced  brachials  at  the  upper  end  of  a.  Plates  of  the  whole  calyx 
thick  and  smooth.  Anal  plates  lost  except  the  first  plate  in  specimen 
b  which  is  so  rotated  out  of  its  position  that  its  exact  shape  cannot 
be  determined.    Ventral  sac  unknown. 

The  stem  is  extraordinary  in  that  there  is  a  number  of  thick  heavy 
columnals  below  the  basal  circlet.  These  diminish  in  diameter  and 
in  length  distally  (see  Plate  V,  fig.  3) .  The  suture  lines  between  the 
columnals  are  distinct  and  gently  depressed  below  the  surface ;  more- 
over the  columnals  are  free  along  their  joint  faces  as  illustrated  in 
b,  d  and  e  in  which  they  have  partly  slipped  out  of  line.  The  suture 
lines  in  e  show  crenelate  edges  and  the  exposed  parts  of  the  joint 
faces  in  d  and  others  show  the  radially  disposed  crenellae.  The  prox- 
imal suture  at  the  base  of  the  calyx  is  slightly  indented  just  below 
each  basal.  Distally  the  diminishing  heavier  columnals  give  way  to 
round  thin  ones  of  less  than  one  millimeter  in  thickness.  In  speci- 
men e  there  are  two  of  these  below  the  fifth  heavy  segment,  then  one 
thicker  segment  comparable  in  size  to  the  fifth  distal  and  beyond  this 
another  thin  segment  (Plate  V,  fig.  3).  Beyond  this  the  stem  char- 
acters are  unknown.  Whether  it  continues  as  a  series  of  thin  ossicles 
or  as  thin  ones  alternating  with  heavier  ones  must  await  discovery  of 
new  material. 

The  following  measurements  taken  in  millimeters  are  added : 

a  J>        c        d  e 

Length  of  stem  preserved 7.6  6.1  2.4     6.5  5.5 

Diameter  of  largest  columnal .4.1  3.8  3.0      3.7  3.0 

Length  of  largest  columnal _* ....... 3.1  2.9  1.7     2.4  1.6 

Length  of  calyx  to  top  of  radials 5.0  5.0  4.0 

Diameter  of  calyx  at  top  of  radials 5.1  5.0      

Length  of  anterior  radial 3.0  2.8      

Dr.  Frank  Springer  to  whom  a  photograph  of  this  species  was 
submitted  writes4  that  "there  is  a  tendency  in  some  members  of  the 
Cincinnatian  series  toward  such  enlargement.  One  form  called 
Seterocrinus  juvenis  not  only  does  that  but  the  crown  has  broken 


■*  Personal  communication,  April  26,  1925. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

off  above  the  basals  and  then  rejuvenated  so  that  we  get  a  crown  no 
larger  than  the  stem. '  '5 

Occurrence :  In  the  Fort  Atkinson  limestone  (Middle  Maquoketa) 
at  Fort  Atkinson,  Iowa.  Collected  by  A.  0.  Thomas  and  H.  S.  Ladd. 
The  specimens  are  preserved  in  the  paleontological  collections  of  the 
University  of  Iowa.  Specimens  a  to  e  are  numbered  respectively 
3771-3775. 

Ectenocrinus  rwymondi  Slocom 

PL  II,  fig.  2. 

1924.    Ecteiwcrinus  raymondi  Slocom,  Iowa  Geol.  Surv.,  Vol.  XXIX,  p.  337, 

pi.  XXIX,  figs.  5-9. 

A  fine  specimen  with  six  expanded  arms  lying  anterior  side  upper- 
most was  found  attached  to  a  slab  of  soft  shaly  dolomitic  limestone 
near  Clermont.  In  general  proportions,  shape  and  size  of  the  calyx 
and  stem  characters,  it  is  very  similar  to  Slocom 's  holotype  from  the 
same  locality.  The  specimen  was  removed  from  the  slab  and  the 
anal  side  was  uncovered  but  unfortunately  the  anal  series  of  plates 
are  lost,  and  some  of  the  other  plates  of  the  posterior  side  are  much 
displaced. 

The  five  basals  are  more  regularly  pentagonal  than  in  the  holo- 
type and  the  complete  radials  show  well  the  small  facets  at  their 
basal  angles  where  they  meet  the  neighboring  inferradials.  Three  of 
the  radials  are  compound  and  two  are  complete.  The  anterior  radial 
is  the  largest  plate  in  the  calyx ;  superficially  it  appears  to  be  four- 
sided  but  the  small  edges  at  the  lower  angles  increase  the  number  of 
sides  to  six.  The  other  complete  radial  is  heptagonal  due  to  trunca- 
tion of  its  upper  right  hand  corner  for  the  reception  of  the  first  anal 
plate.  The  three  superradials  are  four-sided  except  the  posterior 
one  which  is  pentagonal  due  to  position  of  the  anal.  Primibrachs 
two,  the  first  quadrangular,  wider  than  long,  the  second  pentangu- 
lar, also  wider  than  long.  Secundibrachs  many,  one  arm  has  over 
thirty;  rectangular  or  wedge-shaped  and  uniserially  arranged. 
Sides  of  the  plates  flat.  The  outspread  position  of  the  arms  is  ad- 
vantageous for  study  but  no  evidence  can  be  seen  of  the  "shallow, 
rounded  grooves"  mentioned  by  Slocom;  slender  ramules  are  pres- 
ent and  attached  to  the  ventral  side  of  the  arms. 

Stem  round,  tapering,  columnals  thin. 


s  For  illustration  see  H.  juvenis  Hall,  24th  Bep.  New  York  State  Cab.  Nat. 
Hist.,  1872,  pi.  5,  figs.  9,  10.  Also  32nd  Ann.  Rept.  Ontario  Dept.  of  Mines, 
Part  IV,  p.  10,  pi.  I,  fig.  7,  1925. 


MAQUOKETA  CYSTOIDS  AND  CRINOIDS  15 

Length  of  stem  3.85  mm. ;  length,  of  calyx  to  top  of  IBr2,  8.25  mm. ; 
length  of  largest  arm  above  IBr2,  28.5  mm. 

Occurrence :  Elgin  shaly  limestone  (part  of  Lower  Maquoketa), 
Root's  farm,  2.5  miles  northeast  of  Clermont,  Iowa.  Collected  by 
A.  0.  Thomas.    University  of  Iowa  Collection:,  number  3770. 

Cyathocrinidae 

Porocrinus  fayettensis  Slocom 

Plates  II,  figs.  9-16;  IV,  fig.  8;  V,  figs.  6,  7. 

1924.    Porocrinus  fayettensis  Slocom,  Iowa  Geol.  Surv.,  Vol.  XXIX,  p.  333, 
pi.  XXIX,  figs.  14-22,  pi.  XXX,  fig.  14. 

Four  specimens  (nos.  3696,  3697a,  3697b,  3699)  and  some  frag- 
ments referable  to  this  species  were  found  at  the  old  Fort  Atkinson 
quarry.  They  preserve  more  or  less  of  the  thin-ossicled  tapering 
stem.  Three  of  them  are  partly  imbedded  in  a  hard  matrix  but  the 
fourth  (no.  3696)  is  free.  It  is  nearly  globular  in  shape  and  the 
ornamenting  ridges  are  sharper  and  slightly  more  nodose  than  on 
Slocom 's  paratypes  which  are  at  hand  for  comparison.  Moreover, 
none  of  the  Fort  Atkinson  specimens  show  the  fine  granulations  ob- 
served by  Slocom  on  his  specimens  from  Clermont  and  Bloomfield. 

One  specimen  (no.  3693)  with  decidedly  smooth  but  not  ridgeless 
plates,  has  prominent  transverse  ridges  on  the  inf  rabasals  just  above 
the  stem-facet  and  well  sunken  and  somewhat  reduced  fold-areas. 
It  was  found  in  a  road  gutter  about  two  miles  southeast  of  Nordness, 
Winneshiek  county.  Several  loose  plates,  chiefly  radials,  were  also 
found  here. 

Another  interesting  theca  (no.  3692)  picked  up  at  this  locality  is 
laterally  compressed  and  is  decorated  with  five  prominent  angular 
ridges  which  rise  at  the  lateral  infrabasal  sutures  and  pass  to  the 
middle  of  the  basals.  Here  they  divide  into  a  Y  each  upper  branch 
of  which  extends  to  an  arm-facet  above.  Other  ridges  on  the  thecal 
plates,  except  as  noted  ahead,  are  much  subdued  or  practically  want- 
ing. This  ridge  pattern  divides  the  surface  of  the  theca  into  ten 
polygons,  the  lower  five  of  which  are  elongate  pentagons,  the  base  of 
each  in  turn  being  an  edge  of  the  stem-facet ;  the  five  upper  polygons 
are  subrhomboidal  in  shape,  their  distal  angles  being  rounded  and 
situated  between  the  arm-facets.  A  light  but  readily  discernible 
horizontal  ridge  follows  the  shortest  diagonal  of  each  rhomb  and 
pentagon.  Each  pentagon  and  each  rhomb  encloses  two  fold-areaa 
except  posteriorly  where  on  account  of  the  radianal  plate  one  rhomb 


16  IOWA  STUDIES  IN  NATURAL  HISTOEY 

and  one  pentagon  have  each,  an  additional  one  making  a  total  of 
twenty-two.  The  fold-areas  are  much  less  sunken  than  in  typical 
individuals  of  this  species.  As  usual  in  this  genus  the  fold-areas 
occur  at  the  common  corners  of  three  plates  and  the  angle  of  each 
plate  is  bisected  by  a  median  fold  parallel  to  which  are  successively 
shorter  folds  extending  to  the  suture.  In  normal  fold-areas  the 
ridges  are  of  equal  size  and  the  number  of  folds  on  each  side  of  the 
median  is  from  three  to  five.  In  the  specimen  under  discussion  only 
the  uppermost  and  lowermost  fold-areas  approach  normality;  the 
others  are  peculiar  in  that  the  median  fold  is  conspicuously  heavy 
and  reaches  almost  to  the  center  of  the  plate.  The  parallel  folds  are 
much  shorter  and  reduced  to  two,  one  or  none,  while  along  the  upper 
edge  of  the  radianal  even  the  heavy  median  folds  are  virtually  obso- 
lete. The  reduction  of  the  folds  is  most  nearly  complete  along  the 
periphery  of  the  theca  especially  on  the  right  side  but  all  the  fold- 
areas  except  the  four  at  the  level  of  the  anus  exhibit  more  or  less 
loss.  The  three  strong  median  ridges  separated  by  120  degree  angles 
are  striking  decorations  of  the  theca  (see  Plate  V,  fig.  6).  Height 
of  specimen,  10.1  mm.,  anterior  diameter,  11.2  mm.,  lateral  diameter, 
8.0  mm. 

The  differences  between  this  specimen  and  the  types  of  the  species 
are  greater  than  those  existing  between  some  of  the  species  of  Por- 
ocrinus  but  the  authors  prefer  to  regard  these  characters  as  an  indi- 
vidual variation  until  more  material  illustrating  the  same  features 
is  found. 

Miscellaneous  crinoidal  remains 

In  addition  to  the  more  complete  specimens  treated  above  a  quan- 
tity of  crinoidal  fragments  consisting  mainly  of  stems  and  isolated 
plates  has  been  collected.  Some  of  the  parts  are  readily  identified, 
others  belong  to  unknown  species  and  in  some  cases  more  material 
will  be  necessary  for  final  determination.  Some  of  the  parts  found 
are  illustrated  on  Plate  III. 

Among  the  material  is  a  number  (figs.  1-4,  6,  7)  of  isolated  plates 
of  Carabocrinus,  close  to  (7.  slocomi  costaius  Poerste.  Figure  1  rep- 
resents a  large  coarsely  ribbed  radial  which  shows  well  the  cuneate 
areas  and  the  diagonal  bordered  grooves  on  either  side  of  the  arm- 
facet  ;  figures  2  and  4  are  similar  but  smaller  and  less  perfect.  Fig- 
ure 3  is  a  complete  radial  of  C.  slocomi;  under  a  strong  lens  it  shows 
very  well  the  fine  shagreen  mentioned  by  Foerste.    Figures  6  and  7 


MAQUOKETA  CYSTOIDS  AND  CRINOIDS  17 

are  typical  infrabasals  of  this  genus.  All  the  above  were  collected 
by  H.  S,  Ladd;  number  1  at  Stockton,  Illinois  (uppermost  beds  of 
the  Maquoketa),  numbers  2  and  4  at  Port  Atkinson  (Fort  Atkinson 
limestone  member)  and  numbers  6  and  7  at  Clermont  (Clermont 
shale  member) . 

Figures  10  and  11  are  typical  of  a  number  of  plates  which  are 
thick  and  heavy  centrally  and  have  smooth  or  slightly  nodose  sur- 
faces, except  along  the  borders  where  there  is  a  more  or  less  con- 
spicuous row  of  nodes  or  short  ridges  at  right  angles  to  the  edges. 
Collected  by  A.  0.  Thomas  in  road  gutters  about  two  and  one-half 
miles  southeast  of  Nordness,  Winneshiek  county,  Iowa  (Elgin  lime- 
stone member) . 

Figures  12  to  14  are  proximal  portions  of  stems  bearing  the  lower 
plates  of  the  cup.  They  are  fairly  common  and  are  thought  to  be- 
long to  the  Heterocrinidae.  They  were  collected  by  H.  S.  Ladd,  num- 
ber 12  in  the  Clermont  shale  pit  near  Clermont  and  number  13  in 
the  upper  part  of  the  Elgin  member  in  section  17,  Orleans  township, 
Winneshiek  county,  Iowa. 

Figures  15  and  16  are  two  views  of  the  base  of  a  small  delicate 
crinoid.  There  are  five  plates  of  equal  size,  curved,  smooth,  and 
gradually  expanding  into  a  bowl-shaped  patina ;  the  plates  are  flat- 
tened below  and  at  their  union  are  excavated  for  the  reception  of  a 
small  round  stem  while  distally  the  median  border  of  each  plate  is 
produced  into  an  angle.  The  height  of  the  specimen  is  5  mm.  and 
its  greatest  width  is  a  little  over  8  mm.  Collected  by  A.  0.  Thomas 
two  and  one-half  miles  southeast  of  Nordness  (Elgin  member). 

Figures  17  to  22  are  various  parts  of  crinoid  stems.  The  first  is  a 
thin  segment  of  a  very  small  round  stem  along  whose  periphery  is 
a  series  of  strong  spines.  The  diameter  of  the  round  portion  is  under 
2  mm.  Figure  18  is  a  side  view  of  a  thick  circular  segment  whose 
height  is  less  than  its  width.  Its  side-face  is  convex  and  there  is  a 
slight  rebate  along  the  suture  line.  The  surface  is  marked  by  fine 
granules  and  the  joint-face  is  flat  with  a  small  pentapetalous  lumen. 
It  may  be  assigned  doubtfully  to  Atactocrinus.  Figure  19  is  a  short 
piece  of  a  sharply  pentagonal  stem  composed  of  fourteen;  segments 
which  alternate  in  thickness  and  somewhat  in  lateral  extent.  At  the 
angles  the  rims  are  produced  into  sharp  points  which  hook  down- 
ward. Lumen  of  stem  is  large  and  round.  In  the  latter  respect  it 
resembles  the  stems  of  certain  cystids.  Figure  20  is  a  fragment  of 
a  stem  9.4  mm.  long  and  3.4  mm.  in  diameter.    It  is  star-shaped  in 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

cross  section  and  the  sharp  ridges  at  the  angles  of  the  stem  are  beset 
at  intervals  with  thornlike  points.  The  segments  are  very  thin  there 
being  about  23  in  five  mm. ;  the  suture-lines  are  flush  and  inconspic- 
uous except  under  a  high  power  lens.  The  joint-face  is  marked  by 
delicate  marginal  crenellse;  lumen  pentagonal  and  relatively  large. 
Figure  21  is  an  incomplete  slender  stem  32  mm.  in  length.  It  is  made 
up  of  a  series  of  star-shaped  segments  with  strong  heavy  points.  In 
the  succession  of  segments  the  points  are  so  arranged  that  they  form 
a  spiral  about  the  stem.  This  type  of  stem  is  fairly  common  in  the 
Fort  Atkinson  member.  Figure  22  is  a  part  of  the  stem  of  Demdro- 
crinus  kayi  Sloeom.  It  is  pentagonal  in  cross  section  and  42  mm.  in 
length.  Segments  are  alternately  thick  and  thin,  the  thick  ones  be- 
ing nodose  at  the  angles.  The  joint-faces  are  marked  by  a  distinct 
pattern  of  crenellae  which  extend  from  the  margin  to  the  small  five- 
sided  lumen.  Fragments  and  isolated  segments  of  the  stem  of  this 
species  are  common  in  the  marly  shales  near  the  top  of  the  Brainard 
member  and  are  very  plentiful  at  the  type  locality,  Patterson's 
Springs,  near  Brainard,  Iowa.  Numbers  17  and  19  to  22  were  col- 
lected by  H.  S.  Ladd.  Number  17  in  Fairfield  township,  Jackson 
county  (uppermost  beds  of  Maquoketa) ,  number  19  in  Orleans  town- 
ship, Winneshiek  county  (Elgin  member),  number  20  at  Clermont 
(Clermont  member),  number  21  at  Fort  Atkinson  (Fort  Atkinson 
member),  and  number  22  at  Patterson's  Springs  (Brainard  mem- 
ber) .  Number  18  was  collected  by  A.  0.  Thomas  in  the  road  gutters 
two  and  one-half  miles  southeast  of  Nordness  (Elgin  member).  On 
Plate  IV,  figures  9  and  10,  are  illustrated  two  views  of  a  crushed 
specimen  preserving  a  part  of  the  arms  and  stem.  The  plates  of  the 
lower  cup  are  out  of  place  and  some  of  them  are  lost.  The  speci- 
men aids  the  collecter  in  associating  certain  stem  and  arm  fragments 
which  occur  abundantly  in  the  Ft.  Atkinson  beds. 


A  THEORY  OF  ORIGIN  OF  SOME  LIMESTONE 
MASSES  AND  SEPTARIA 

A.  L.  Lugn 

Certain  lensy  "limestone"  masses  that  abound  in  the  Des  Moines 
series  of  the  Coal  Measures  strata  of  south  central  Iowa  have  been 
observed  by  many  workers.  These  masses  have  been  rather  indiscrim- 
inately called,  " limestone  boulders' ',  nodules,  limestone  lenses  and 
septaria.  The  first  term  applies  to  none  while  the  other  terms  are 
applicable  to  some  of  the  masses.  It  is  the  purpose  here  to  state  a 
theory  of  secondary  origin,  arrived  at  by  the  writer  during  the  field 
investigation  and  based  entirely  on  field  evidence.  Subsequent  to 
the  field  work  and  after  the  theory  suggested  below  had  taken  defin- 
ite form,  the  writer  in  conference  with  Dr.  W.  A.  Parks  of  Toronto, 
Canada,  learned  that  he  had  observed  similar  limestone  masses  in  the 
shales  of  Ordovician  age  in  Ontario.  These  he  had  described  in  a 
manuscript  which  he  was  preparing  and  was  suggesting  an  explana- 
tion of  their  origin  essentially  in  accord  with  the  views  here  present- 
ed.1 

Two  distinct  types  of  these  masses  were  studied,  which  for  con- 
venience, here  only,  are  designated,  type  A  (strictly  limestone 
lenses)  and  type  B  (true  septaria).  The  first  type  (A)  occurs  as 
lensy  masses  varying  from  small  ovoid  bodies  a  few  inches  in  diam- 
eter to  large  flattened  masses  several  yards  in  maximum  dimensions. 
The  two  longer  dimensions  are  oriented  parallel  to  the  bedding 
planes  of  the  shale  in  which  they  lie.  In  the  sections  where  they  may 
be  seen,  they  are  confined  to  definite  horizons,  commonly  only  to  one. 
The  individual  sizes  increase  as  the  horizon  is  traced  toward  a  larger 
lens  of  limestone  at  the  same  level.  These  larger  platelike  lenses 
have  an  areal  extent  of  a  few  acres  to  a  few  square  miles  and  are  not 
limited  to  very  definite  places  in  the  series.  They  are  of  little  value 
in  stratigraphy  except  where  their  horizons  can  be  accurately  re- 


i  Since  the  preparation  of  the  present  manuscript,  Dr.  Parks '  paper,  above 
referred  to,  has  come  from  the  press.  It  is  on  "The  Stratigraphy  and  Corre- 
lation of  the  Dundas  Formation,' '  in  the  Thirty-Second  Annual  Eeport  of  the 
Ontario  Department  of  Mines,  Vol.  XXXII,  part  VII,  pp.  97-99,  1923.  (Pub- 
lished 1925). 

19 


20  IOWA  STUDIES  IN  NATURAL  HISTOEY 

lated.  This  is  possible  only  where  exposures  are  close  together.  The 
smaller  masses  of  type  A  border  or  fringe  the  larger  lenses.  This 
relation  is  shown  in  cross-section  in  figure  1. 

The  small  masses  of  this  first  type  are  always  more  prolific  in 
fossil  remains  than  the  surrounding  shale  and  in  most  eases  a  little 
less  so  than  the  larger  lenses.  Under  the  microscope  most  of  the 
lime  carbonate,  not  occurring  as  fossil  shells,  is  seen  to  be  crystalline, 
suggesting  that  it  is  a  secondary  deposit  from  ground  water.  It  can 
hardly  be  recrystallized  original  calcium  carbonate  for  the  original 
shells  are  preserved  and  the  crystalline  material  is  confined  to  the 


Figure  1.  Relationship  of  the  fossiliferous  limestone  masses  to  the  larger 
lenses,  showing  their  gradation  in  size  and  their  occurrence  at  the  same  level. 

spaces  between  the  fossils  and  also  encloses  more  or  less  of  the  argil- 
laceous sediment.  The  surrounding  shale  is  quite  barren  of  original 
fossil  remains  but  in  places  molds  of  brachiopod,  pelecypod  and  gas- 
tropod shells  abound.  The  lime  carbonate  of  the  fossil  shells  has  been 
removed  by  solution  and  now  the  shale,  in  most  places,  is  relatively 
lean  in  calcium  carbonate.  The  fossiliferous  limestone  masses  and 
lenses  still  preserve  the  original  bedding  which  can  be  traced  into 
the  adjacent  shale.  The  bedding  planes  bend  upward  and  down- 
ward in  passing  through  them.    This  is  shown,  in  figure  2. 

It  is  believed  that  the  masses  of  type  A  and  many  of  the  larger 
limestone  lenses  can  be  explained  on  the  basis  of  a  secondary  con- 
centration of  calcium  carbonate.  The  sediment  at  the  time  of  de- 
position was  highly  argillaceous  and  essentially  uniform  throughout. 
Shells  of  organisms  were  more  or  less  evenly  scattered  through  the 
mud.  Certain  thin  zones  or  limited  horizons  of  small  lateral  extent 
may  originally  have  been  a  little  richer  in  the  number  of  calcareous 
shells  but  the  deposit  as  a  whole  wras  essentially  one  of  shale -forming 
material.  With  subsequent  uplift  above  sea  level,  the  moderately 
compacted  material  became  subject  to  the  action,  of  ground  water. 


LIMESTONE  MASSES  AND  SEPTARIA 


21 


Calcium  carbonate,  dissolved  from  the  shale,  became  concentrated 
in  certain  zones,  preserving  the  original  fossils  and  accounting  for 
the  secondary  calcite  which  surrounds  the  shells  in  these  masses  and 
lenses.  This  process  has  been  of  diminishing  importance  as  the  ma- 
terial has  become  more  and  more  compact.  The  masses  and  lenses 
thus  preserve  the  original  bedding  and  very  nearly  the  original 
thickness  of  the  bed.  The  bending  of  the  bedding  planes  on  either 
side  of,  through  and  around  them  is  the  result  of  settling  and  com- 
pacting of  the  enclosing  sediment.  This  volume  shrinkage  is  in  part 
due  to  the  removal  of  lime  carbonate  by  solution  and  leaching,  leav- 
ing only  more  or  less  distorted  molds  of  the  original  fossil  shells  in 
the  surrounding  shale.  The  abundance  of  molds  of  shells  in  the 
shale  excludes  the  possibility  of  the  extreme  localization  of  living 
organisms  that  has  sometimes  been  assumed  for  these  flat  limestone 
lenses.  The  present  limestone  lenses  then  represent  those  favorable 
places  or  zones  where  secondary  lime  carbonate  has  been  precipitated 
before  the  enclosed  shells  had  been  dissolved. 


Figure  2.     The  f  ossilif  erous  limestone  masses,  showing  the  bending  of  the  bed- 
ding planes  and  their  general  relation  to  the  enclosing  shale. 

Figure  3.     The  septaria,  showing  their  occurrence  at  different  levels  and 
their  relation  to  the  surrounding  shale. 


Masses  of  the  B  type  are  true  septaria.2  They  contain  no  fossil 
shells  or  at  least  fewer  shells  than  the  surrounding  shale.  The  bed- 
ding planes  of  the  enclosing  shale  do  not  pass  through  but  very 
clearly  bend  around  them.  These  masses  are  made  up  of  about  fifty 
per  cent  crystalline  calcium  carbonate  and  nearly  all  of  the  remain- 
der consists  of  clastic  material  of  textures  below  1/64  mm.  This 
fine  material  is  like  that  of  the  surrounding  shale.  The  septaria  are 
not  limited  to  a  single  horizon,  even  in  a  single  exposure.  The  veins 
of  the  septaria,  which  are  characteristic  of  type  B,  are  usually  filled 

2Grabau,  A.  W.,  "  Intercretions '  \  Principles  of  Stratigraphy,  pp.  719-720, 

(lyio} . 


22  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

with  very  clear  caleite,  in  some  cases  with  pyrite  and  in  a  few  a  little 
sphalerite  was  found. 

The  complete  or  nearly  complete  absence  of  fossils  in  the  septaria 
is  believed  to  be  due  to  a  nearly  complete  solution  of  all  fossil  shells 
and  a  leaching  of  the  shale  of  its  lime  carbonate  before  the  secondary 
concretionary  accumulation  as  septaria  began.  That  these  masses 
are  not  confined  to  definite  horizons  leads  to  the  conclusion  that 
their  centers  of  growth  were  determined  after  the  local  solution  and 
leaching  of  the  primary  calcium  carbonate  had  taken  place.  It  is  not 
evident  just  what  determined  the  position  or  the  beginning  of  these 
secondary  centers  of  crystallization.  It  is  evident,  however,  that 
with  the  accumulation  of  the  secondary  caleite  the  surrounding  shale 
is  largely  pushed  out  of  the  way  by  the  force  of  crystallization.  The 
growing  septaria  incorporated  some  of  the  original  sediment  now 
heterogeneously  scattered  through  them.  This  accounts  for  the 
bending  of  the  bedding  planes  around  them  and  for  the  absence  of 
bedding  within. 

If  the  evidence  presented  above  has  been  correctly  interpreted  it 
is  clear  that  many  if  not  most  small  masses  of  limestone  that  occur 
in  thick  and  extensive  shale  formations  can  be  explained  without 
assuming  any  great  changes  of  sedimentary  conditions  during  the 
deposition  of  the  formation.  Their  explanation  does  not  require  a 
shift  of  land  and  sea  relations,  a  change  of  currents,  or  the  assump- 
tion of  extreme  localization  of  organisms.  If  a  theory  of  secondary 
formation  can  apply  to  small  masses  of  limestone  in  great  shale  for- 
mations, as  parts  of  the  Des  Moines  series,  may  it  not  within  reason- 
able limits  be  applied  in  part  to  larger,  thicker  and  more  extensive 
strata  of  limestone  throughout  the  geologic  column,? 

The  writer  is  indebted  to  Prof.  W.  A.  Parks  of  Toronto,  Canada 
and  to  Prof.  A.  C.  Trowbridge  of  Iowa  City,  Iowa  for  encouragement 
in  presenting  the  above  view;  and  to  Prof.  A.  0.  Thomas  also  of 
Iowa  City  for  criticisms  of  the  manuscript. 


METHODS  OF  COLLECTING  SEDIMENT 
SAMPLES  FROM  THE  MISSISSIPPI  RIVER 

A.  L.  Lugn 

(PLATES  VII  and  VIII) 

The  object  of  this  paper  is  to  describe  the  methods  and  procedure 
employed  in  collecting  samples  of  sediment  from  the  Mississippi 
river  during  the  summer  of  1925.  A  few  suggestions  which  oc- 
curred to  the  writer  while  engaged  in  the  field  operation  are  added. 
It  is  not  the  purpose  to  discuss  the  laboratory  study  of  these  mater- 
ials nor  to  state  conclusions. 

Various  types  of  sediment  samples  were  taken  from  Davenport, 
Iowa,  to  Cairo,  Illinois,  a  distance  of  almost  exactly  five  hundred 
miles  as  measured  along  the  main  channel.  The  acquisition  of  these 
samples  was  financed  in  part  by  the  Graduate  College  of  the  State 
University  of  Iowa  and  was  done  under  the  supervision  of  Professor 
A.  C.  Trowbridge  of  the  Department  of  Geology.  Except  for  some 
previous  work  done  by  Dr.  Trowbridge  at  the  mouths  of  the  river 
and  in  the  Gulf  of  Mexico,  the  present  project  is  the  beginning  of  a 
comprehensive  study  of  the  whole  Mississippi  river  system.  It  seems 
proper  at  this  time  to  present  the  field  methods  and  procedures  em- 
ployed, since  the  present  work  is  the  first  of  its  kind  to  be  done  in  a 
systematic  study  of  any  considerable  length  of  a  great  river. 

There  are  many  factors  to  be  considered  in  an  initial  undertaking 
of  such  a  project.  A  suitable  boat  or  boats  must  be  secured,  sam- 
pling apparatus  must  be  selected  or  invented,  the  types  of  samples 
to  be  collected  must  be  decided  upon,  a  procedure  for  taking  each 
kind  of  sample  and  methods  of  recording  data  must  be  worked  out. 
The  spacing  and  selection  of  places  at  which  to  collect  material  must 
also  be  determined  in  some  systematic  way.  Most  of  these  things 
could  not  be  decided  before  beginning  the  work  as  there  were  no 
precedents  to  follow. 

A  suitable  and  adequate  boat  is  almost  indispensable  in  making  a 
study  of  a  considerable  length  of  a  large  river.  The  writer  was 
very  fortunate  in  securing  the  boat  shown  in  Plate  VIII,  owned  by 
Mr.  C.  B.  Delene  of  Moline,  Illinois.  Mr.  Clovis  E.  Delene  Jr.,  a 
student  at  Augustana  college,  accompanied  the  writer  as  boats- 

23 


24  IOWA  STUDIES  IN  NATURAL  HISTOEY 

man  and  general  helper.  In  these  capacities  he  was  efficient  and 
capable  in  every  way. 

The  Delene  was  propelled  by  a  stern  wheel  operated  by  a  Ford 
engine  and  could  make  from  five  to  seven  miles  an  hour  in  quiet 
water.  In  pulling  against  the  current  the  rate  of  progress  was 
rather  slow  but  other  desirable  features  outweighed  this  disadvan- 
tage. Some  of  these  features  were :  length  32  feet  over  all,  beam  8 
feet,  flat  bottom  and  draft  of  only  8  to  12  inches.  The  shallow  draft 
made  landing  possible  at  almost  any  point  as  well  as  permitting 
travel  in  shoal  water.  The  cabin  was  commodious  and  comfortable 
and  with  the  large  space  under  the  forward  deck  gave  ample  room 
for  all  supplies  and  equipment.  As  collected  materials  accumulated, 
they  were  shipped  to  Iowa  City  from  time  to  time.  The  cabin  was 
tightly  screened  and  so  constructed  as  to  give  complete  protection 
to  the  occupants  from  both  weather  and  insects.  Every  night  was 
spent  on  the  boat  and  all  cooking  was  done  on  a  portable  gasoline 
camp  stove. 

A  fourteen;  foot  flat-bottomed  skiff  of  the  "  John-boat J?  type  was 
towed  alongside.  This  was  found  to  be  an  essential  part  of  the  out- 
fit for  it  allowed  greater  mobility  and  was  used  in  taking  almost  all 
of  the  samples.  Such  a  small  boat  is  also  of  great  value  for  general 
use  and  is  a  necessity  in  case  of  motor  or  other  boat  trouble.  It  can 
be  propelled  by  an  outboard  motor  or  rowed  by  hand.  In  the  pres- 
ent instance  only  oars  were  used  but  the  writer  recommends  the  out- 
board motor.  One  man  handled  the  skiff  while  the  other  operated 
the  sampling  apparatus. 

In  case  an  intensive  study  of  a  short  segment  of  a  large  river  is  to 
be  made,  the  larger  boat  may  not  be  so  essential  since  bases  of  opera- 
tion can  be  established  at  towns  or  camps  and  only  a  small  boat  with 
outboard  motor  need  be  used.  Camp  may  be  moved  as  often  as  de- 
sired either  by  ear  or  by  boat.  This  procedure  is  recommended  only 
where  an  accessible  portion  of  a  river  of  less  than  one  hundred  miles 
is  to  be  studied  in  a  field  season  of  six  to  ten  weeks.  A  small  river 
having  a  shallow  channel  may  be  fairly  conveniently  studied  by 
traveling  in  a  car  and  many  of  the  samples  of  sediment  can  be  taken 
by  operating  the  samplers  from  bridges,  since  small  streams  are  us- 
ually bridged  at  short  intervals.  Travel  in  this  way  is  faster  than 
by  boat  and  may  be  of  considerable  value  even  on;  some  large  streams 
when  a  boat  is  not  available.  However,  the  disadvantages  are  ob- 
vious. 


COLLECTING  SEDIMENT  SAMPLES  25 

Sediment  samples  were  taken  which  are  believed  to  represent  most 
nearly  the  river's  activity  and  working  capacity  at  the  time  of  col- 
lection. It  was  decided  at  the  outset  to  collect  material  from  the  bed 
of  the  river,  from  sand  and  mud  bars,  from  islands  as  well  as  sus- 
pended debris.  In  time  of  high  water  many  of  the  bars  are  sub- 
merged and  in  such  cases  "bar"  samples  are  taken  as  "bottom" 
samples.  At  the  time  the  present  project  was  started  the  river  was 
rising  and  this  continued  during  the  time  taken  to  traverse  about 
one  half  of  the  distance  covered.  A  receding  stage  was  experienced 
during  the  remainder  of  the  distance  to  Cairo  and  low  water  pre- 
vailed during  the  return  trip.  This  was  considered  a  favorable  se- 
quence of  water  conditions.  Most  of  the  samples  were  taken  on  the 
down  river  part  of  the  trip  due  to  the  favorable  stage  of  the  water 
and  to  the  uncertainty  in  regard  to  the  time  required  to  carry  out 
the  project.  There  is  also  considerable  economy  of  time  in  making 
the  collections  while  going  down  stream. 

One  of  the  essential  requirements  of  bottom  samples  is  that  they 
represent  the  material  being  handled  by  the  river  at  the  time  collec- 
tion is  made.  For  this  reason  samples  that  represent  a  vertical  sec- 
tion of  even  a  few  inches  of  bottom  sediment  are  likely  to  be  unde- 
sirable. Sediment  that  is  scraped  from  the  bed  of  the  river  to  a 
depth  of  less  than  an  inch  will  best  represent  the  material  being 
handled  by  the  river  at  that  place  and  time ;  for  the  bottom  surface 
at  any  place  is  either  a  site  of  deposition  or  of  erosion.  The  methods 
and  apparatus  used  in  taking  bottom  materials  will  be  described  in 
detail  later. 

Samples  of  debris  from  bars  and  islands  were  easily  taken  by 
hand  and  preserved  in  stout  cloth  bags.  The  conclusion  was  reached 
early  in  the  work  that  samples  of  material  dredged  or  pumped  from 
the  river's  bed  might  be  of  great  value.  Accordingly,  gravel  and 
sand  samples  were  secured  from  commercial  dealers  wherever  pos- 
sible. In  all  cases  these  were  taken  by  hand  from  the  dredge  or 
barge  or  from  the  unscreened  pile  and  represented  the  "river  run". 
Dredged  material  of  this  kind  is  not  of  quite  the  same  value  as  the 
bottom  samples  but  does,  in  nearly  every  case,  represent  the  work 
of  the  river  at  its  maximum  capacity.  A  "live"  gravel  or  sand  bar 
may  be  completely  removed  in  a  single  flood  or  such  a  bar  of  large 
dimensions  may  be  deposited  in  one  period  of  high  water.  A  me- 
chanical analysis  of  gravel  or  sand  from  such  a  deposit  gives  a  com- 
posite result  and  shows  nothing  of  the  sorting  within  the  bar.    The 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

greatest  value  of  such  samples  is  that  they  contain  the  largest  gravels 
and  cobbles,  sometimes  with  diametral  dimensions  of  four  to  six 
inches.  Such  large  cobbles  are  usually  of  more  or  less  local  origin, 
from  nearby  tributaries ;  in  all  cases  they  show  the  effect  of  stream 
wear  and  bear  evidence  of  water  handling.  The  size  of  such  sam- 
ples was  necessarily  large  in  order  to  represent  the  various  textural 
grades  in  proper  proportion.  They  also  were  preserved  in  stout 
cloth  bags. 

Much  can  be  learned  even  by  a  casual  study  of  the  sand  and  gravel 
piles  of  commercial  dealers.  The  same  type  of  material  can  be  ob- 
served at  many  places  in  the  levees  where  these  have  been  built  of 
sediment  pumped  or  dredged  from  the  river  in  the  immediate  vicin- 
ity. A  few  ' '  levee ' J  samples  were  taken.  In  addition '  '  hand-picked ' ' 
gravels  and  cobbles  were  collected  from  gravel  barges  and  levees  to 
show  the  maximum  sizes,  the  degree  of  rounding,  the  shapes  and  the 
rock  and  mineral  types  in  the  larger  grades. 

Samples  of  mechanically  suspended  matter  were  taken  in  order  to 
find  out  the  texture  and  quantity  of  solid  matter  being  transported 
in  a  known  volume  of  water  at  different  depths  at  the  prevailing 
stage.  These  samples  were  taken  in  most  cases  from  the  main  chan- 
nel where  the  water  was  deepest  and  the  velocity  greatest.  A  half 
gallon  of  water,  with  its  contained  sediment,  was  secured  by  an  ap- 
paratus described  below.  This  was  transferred  to  a  half  gallon 
Mason  fruit  jar  and  the  sediment  allowed  to  settle.  After  a  suffi- 
cient time  the  clear  water  was  siphoned  off  and  the  wet  sediment  was 
preserved  in  an  air-tight  four  ounce  wide-mouthed  bottle.  Usually 
three  such  half  gallon  samples  of  water  and  suspended  sediment 
w^ere  taken  at  the  same  place  but  at  different  depths ;  at  the  surface, 
at  about  one  foot  from  the  bottom  and  at  an  intermediate  depth. 

The  first  device  used  for  collecting  water  samples,  with  suspended 
debris,  was  a  common  kitchen  sink  force  pump,  with  three  sections 
of  garden  hose.  One  twenty  foot  and  two  ten  foot  lengths  of  hose 
were  used.  The  free  end  was  weighted  and  submerged  to  the  chosen 
depth  and  water  was  pumped  into  a  container.  This  apparatus  is 
satisfactory  in  quiet  water  but  is  cumbersome  and  bulky.  It  can  not 
conveniently  be  operated  from  a  small  skiff.  Where  there  is  much 
current  the  intake  or  free  end  of  the  hose  is  carried  down  stream 
and  its  depth  becomes  uncertain. 

The  pump  was  discarded  for  a  simpler  and  far  more  satisfactory 
device,  consisting  of  a  weighted  half  gallon  can  made  of  heavy  gal- 


COLLECTING  SEDIMENT  SAMPLES  27 

vanized  sheet  iron.  It  is  illustrated  on  Plate  VII,  figure  3.  This  can 
was  closed  by  a  one  inch  cork  to  which  a  heavy  cord  was  attached. 
The  whole,  filled  with  air,  was  lowered  into  the  water  on  the  end  of 
a  line  to  the  desired  depth  and  the  cork  pulled  out.  The  apparatus 
filled  easily  and  quickly  and  as  the  neck  and  mouth  had  a  relatively 
small  diameter  very  little  interchange  of  the  contents  with  the  sur- 
rounding water  occurred  in  raising  it  to  the  surface.  It  was  oper- 
ated from  the  skiff  and  to  obviate  the  effect  of  the  current  on  its 
depth  when  submerged  the  boat  was  allowed  to  drift  down  stream 
while  the  can  filled.  This  usually  amounted  to  only  a  few  rods.  The 
total  weight  of  the  device  is  about  nine  and  one-half  pounds.  The 
limit  of  depth  at  which  it  was  found  to  work  satisfactorily  was 
about  forty  feet.  At  greater  depths  the  cork  was  very  hard  to  pull 
out  against  the  increased  pressure.  A  heavier  can  with  double  or 
treble  the  weight  of  the  above  should  operate  at  somewhat  greater 
depths. 

Another  device  for  taking  samples  of  water  and  contained  sedi- 
ment at  almost  any  depth  likely  to  be  encountered  in  a  river  is  il- 
lustrated in  the  drawing  on  Plate  VII,  figure  4.  This  is  a  can,  of  any 
suitable  volume,  similar  to  the  one  described  above  but  attached 
rigidly  to  a  rod  two  or  three  times  its  length.  Two  adequate  weights 
are  also  attached  to  the  rod,  one  at  each  end  and  to  each  of  these  a 
line  is  fastened.  The  apparatus  is  lowered  by  the  line  attached  at 
B,  with  the  open  end  of  the  can  directed  downward.  At  the  proper 
depth  the  line  at  A  is  brought  taut  and  the  one  at  B  is  released  thus 
reversing  the  can,  which  allows  the  air  to  escape  and  water  to  enter. 
This  eliminates  the  difficulty  of  removing  a  cork  against  water  pres- 
sure but  permits  a  little  error  in  quantity  of  contained  suspended 
matter  as  some  water  enters  as  it  is  being  lowered  due  to  the  com- 
pression of  the  air  in  the  can  as  the  depth  increases.  This  error  in- 
creases in  direct  proportion!  to  the  increase  of  pressure  (or  depth) 
but  is  more  or  less  compensated  since  the  quantity  of  suspended 
matter  also  increases  with  depth.  This  device  was  not  put  into 
actual  operation. 

The  "telegraph  snapper "  bottom  sampler  was  the  first  apparatus 
tried  for  taking  material  from  the  river's  bed.  This  device  is  il- 
lustrated on  Plate  VII,  figure  1  (open)  and  figure  2  (closed) .  It  was 
weighted  and  operated  at  the  end  of  a  line  in  the  usual  way.  A 
rigid  rod  would  probably  be  better  than;  a  line  in  quiet  and  relative- 
ly shallow  water.    It  is  opened  and  lowered  to  the  bottom ;  on  strik- 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

ing  the  bottom  the  jaws  are  spread  sufficiently  to  release  the  toggle 
irons  which  hold  them  apart  and  they  close  around  a  small  quantity 
of  sediment.  This  sampler  is  well  adapted  to  taking  uniformly  fine 
materials,  such  as  mud  and  silt  when  fairly  compact,  but  is  unsatis- 
factory in  gravel  and  even  in  fine  sand.  It  does  not  take  a  sufficient 
quantity,  where  the  deposit  contains  particles  over  a  few  millimeters 
in  diameter  nor  does  it  always  close  tightly  enough,  for  large  grains 
may  be  caught  in  such  a  way  as  to  hold  the  jaws  partly  open.  Even 
grains  of  sand  may  hold  the  jaws  far  enough  apart  to  allow  fine 
material  to  be  washed  out  in  lifting  it  to  the  surface.  When  the 
total  quantity  of  heterogeneous  material  secured  is  small  such  losses 
may  be  appreciable.  The  most  serious  objection  to  this  sampler  is 
that  at  nearly  every  trial  sand  grains  worked  into  the  hinges  of  the 
toggles  and  prevented  them  from  completely  releasing  the  jaws. 
The  grains  of  sand  had  to  be  tediously  worked  out  by  moving  the 
parts  by  hand  until  they  operated  freely  again:.  It  commonly  re- 
quired as  many  as  a  dozen  trials  to  secure  a  single  sample.  Even 
had  the  apparatus  worked  perfectly,  it  would  have  been  inadequate 
because  of  its  small  size  and  the  textures  of  material  encountered. 

The  "Shaw"  sampler,  suited  to  taking  fine  sediment,  was  also 
inadequate  for  collecting  gravel  and  sand.  It  could  not  be  used  ex- 
cept in  mud  deposits  and  by  the  time  the  project  was  well  under  way 
the  sampler  designed  by  the  writer  and  described  below  rendered 
its  use  unnecessary.  The  Shaw  sampler  takes  "section"  samples  of 
small  diameter  which  penetrate  the  deposit  to  a  depth  of  several 
inches  and  are  for  that  reason,  as  intimated  above,  unsatisfactory. 

By  the  time  the  first  thirty  miles  of  the  project  had  been  covered, 
it  was  plainly  evident  that  the  sampling  apparatus  in  hand  was  en- 
tirely inadequate  and  that  something  new  would  have  to  be  designed 
and  made.  It  should  be  emphasized  that  any  sampler  had  to  be 
operated  by  hand  and  in  most  cases  from  the  skiff. 

The  device  illustrated  on  Plate  VII,  figures  5,  6,  7  and  8  was  de- 
signed by  the  writer  and  made  at  a  machine  shop  in  Muscatine,  la. 
It  consists  of  two  weights  rigidly  attached  to  a  central  stem  and  a 
loose-fitting  cup,  which  rests  around  a  shoulder  on  the  lower  weight. 
Its  total  mass  is  about  eleven  pounds  and  its  length  over  all  is  nine* 
teen  and  one-half  inches.  The  lower  weight  was  made  from  a  piece 
of  steel  shafting  three  inches  long  and  three  inches  in  diameter.  The 
upper  end  was  turned  off,  making  a  shoulder  one  half  inch  high  and 
exactly  one  and  fifteen-sixteenths  inches  in  diameter  around  which 


COLLECTING  SEDIMENT  SAMPLES  29 

the  cup  fits  loosely.  A  threaded  hole  receives  the  stem  in  the  center 
of  the  top  of  this  weight.  The  lower  weight  weighs  about  five  and 
one-half  pounds.  The  stem  has  a  diameter  of  five-eighths  of  an  inch 
and  is  bent  into  an  eye  at  the  upper  end.  The  upper  weight  is  two 
and  one-half  inches  in  length  and  two  inches  in  diameter  and  was 
sawed  from  a  piece  of  steel  shafting.  It  fits  over  the  stem  and  is 
held  in  place  by  a  rivet.  Its  lower  end  is  about  twelve  inches  above 
the  top  of  the  shoulder  on  the  lower  weight.  It  weighs  about  two 
pounds  and  the  stem  an  equal  amount.  The  cup  was  cut  from  a 
piece  of  boiler  tubing  and  is  six  inches  long.  It  has  an  inside  di- 
ameter of  exactly  two  and  one-sixteenth  inches.  This  inside  di- 
ameter is  one-eighth  inch  greater  than  the  diameter  of  the  shoulder 
on  the  lower  weight  around  which  the  cup  rests.  It  is  important 
that  the  cup  should  fit  neither  too  tightly  nor  too  loosely  around  the 
shoulder.  The  diametral  relations  of  these  parts  must  be  such  that 
the  cup  can  incline  easily  when  the  apparatus  is  prone  and  settle 
back  again  to  the  vertical  position  when  the  sampler  is  brought  up- 
right in  lifting  it  from  the  bottom.  These  positions  may  be  seen  on 
Plate  VII  in  figures  8  and  6  respectively.  The  shoulder  must  be  high 
enough  to  prevent  the  cup  from  slipping  off  too  easily,  in  which  case 
the  load  is  lost  in  raising  it  from  the  bottom.  This  scarcely  ever 
happened.  The  cup  easily  slides  off  the  apparatus  over  the  upper 
weight.  This  allows  other  cups  of  different  size  and  shape  to  be 
used  interchangeably  on  the  same  weight  and  stem  system. 

This  sampler  was  operated  in  most  cases  from  the  stern  of  the 
skiff.  It  was  lowered  to  the  bottom  by  means  of  a  stout  line ;  on 
touching  the  bottom  it  inclines  to  the  prone  position  as  shown  on 
Plate  VII,  figure  8.  The  skiff  was  either  rowed  across  the  current  or 
allowed  to  drift  with  it  and  the  sampler  dragged  for  a  short  distance. 
The  cup  filled  with  bottom  surface  sediment  usually  after  being 
dragged  only  a  few  feet.  It  was  then  raised  to  the  surface  and  the 
contents  were  emptied  into  a  half -pint  Mason  fruit  jar  by  lifting 
the  cup  off  of  the  shoulder.  The  first  part  of  this  operation  is 
shown  on  Plate  VII,  figure  7.  The  apparatus  gave  the  best  results 
when  the  amount  of  line  let  out  was  from  fifty  to  one  hundred  per 
cent  greater  than  the  depth  of  water.  Samples  were  successfully 
taken  at  depths  of  thirty-five  feet  with  only  fifty  feet  of  line. 

The  sampler  described  above  was  very  successful  and  from  its 
first  trial  was  used  to  take  every  bottom  sample  secured  between 
Muscatine,  Iowa,  and  Cairo,  Illinois.     It  takes  a  distinctly  bottom 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

surface  sample  and  was  successful  in  nearly  every  instance  with  the 
first  trial.  The  quantity  of  sediment  was  usually  adequate,  averag- 
ing about  six  fluid  ounces.  It  worked  equally  well  in  mud,  sand 
and  fairly  coarse  gravel,  containing  a  few  pebbles  up  to  an  inch  in 
diameter.  The  leakage  of  fine  material  was  very  little,  in  fact  negli- 
gible in  view  of  the  size  of  the  samples.  All  bottom  samples  were 
preserved  in  their  wet  condition  in  half  pint  air-tight  Mason  fruit 
jars. 

A  systematic  method  of  procedure  to  be  followed  in  collecting 
samples  had  to  be  developed  early  in  the  work.  Obviously  bar,  com- 
mercial and  levee  samples  had  to  be  taken  where  they  were  available, 
so  there  could  be  little  uniformity  in  collecting  these.  Only  repre- 
sentative materials  were  secured  from  typical  and  representative 
bars.  Every  bar  or  island  could  not  be  sampled  nor  was  it  necessary. 
The  determining  factors  in  this  collecting  of  material  were  local  and 
had  to  be  determined  in  the  field. 

Bottom  samples  were  taken  in  series  of  from  about  four  to  ten  at 
a  place  and  in  section  across  the  river  at  right  angles  to  the  channel 
from  bank  to  bank.  These  stations,  where  series  of  bottom  samples 
were  taken,  varied  from  five  to  twenty  miles  apart  along  the  river. 
This  spacing  was  also  determined  by  local  factors.  In  some  places 
the  sections  were  taken  wThere  the  river  was  straight  and  open  with 
no  islands  or  bars  exposed  above  water ;  in  other  places  where  it  had 
many  islands  and  bars.  The  sections  were  usually  directed  from 
one  bank  to  an  island  or  bar  and  from  there  across  to  the  opposite 
bank.  Where  the  river  is  divided  by  an  island  one  side  or  chute  as 
a  rule  is  relatively  narrow  and  shallow  while  the  other  side  is  wide 
and  deep.  The  main  channel  in  most  cases  is  through  the  wider 
chute.  This  relation  prevails  whether  the  island  is  associated  with 
a  bend  in  the  course  of  the  river  or  where  its  course  is  straight.  This 
procedure  of  collecting  samples  was  decided  upon  early  in  the  work 
and  was  adhered  to  throughout.  The  only  modification  made  was  in 
increasing  the  average  distance  between  the  section  stations  as  the 
work  progressed  down  the  river.  Comparable  channel  samples, 
taken  in  the  deepest  and  fastest  water,  were  also  secured  at  irregu- 
lar intervals  between  the  section  stations.  Sets  of  three  half  gallon 
water  samples,  with  their  suspended  sediment,  were  collected  from 
the  main  channel  at  about  every  fourth  or  fifth  section  station.  Mis- 
cellaneous suspended  sediment  samples  were  gotten  at  numerous 
other  places. 


COLLECTING  SEDIMENT  SAMPLES  31 

Sections  of  samples  were  taken  across  all  of  the  main  tributaries 
a  short  distance  above  their  deboueheurs.  Missouri  Eiver  was  given 
especial  attention,  in  that  more  than  the  ordinary  number  of  sam- 
ples were  collected  about  a  mile  above  its  mouth.  Water  with  sus- 
pended matter  was  also  gotten  from  some  of  the  tributaries. 

The  location  of  every  section  station  or  of  other  individual  sam- 
ples was  carefully  noted  on  the  large  scale  charts  published  by  the 
Mississippi  River  Commission.  A  notebook  record  of  depth  of 
water,  position  relative  to  islands  or  bars  and  the  location  relative  to 
a  located  point  on  the  bank  was  made  for  every  sample.  The  posi- 
tion of  a  sample  relative  to  the  main  channel  of  the  river  was  also 
noted.  The  locations  of  samples,  taken  in  a  section,  relative  to  the 
starting  point  were  determined  by  means  of  a  Hymans  pocket  range- 
finder  (Hymans  and  Cox,  Cambridge).  The  large  boat,  the  Delener 
described  above,  was  tied  to  the  bank  or  anchored  off  the  point  of  an 
island  or  bar  and  served  as  a  starting  point.  The  height  of  the  top 
of  the  cabin  above  the  water  line  was  known.  Using  this  fixed  unit, 
the  distance  of  any  point  from  the  boat  could  be  determined  within 
a  few  feet  or  yards.  This  eliminated  the  inconvenience  of  using  a 
stadia  rod. 

The  stage  of  the  water  was  carefully  noted  at  all  gaging  stations 
so  that  the  stage  prevailing  at  the  times  and  places  where  samples 
were  collected  was  known  quite  accurately.  The  velocity  was  esti- 
mated at  many  places. 

The  sediment  samples  collected  from  the  Mississippi  river  accord- 
ing to  the  methods  outlined  above  are  being  subjected  to  laboratory 
studies  of  texture,  shape  and  lithology. 

The  writer  gratefully  acknowledges  the  valuable  criticism  of  this 
paper  by  Professor  A.  0.  Thomas  of  Iowa  City,  Iowa. 


PLATE  I 


(For  explanations  see  next  page) 


/■  \ 


PLATE  I 

Page 

lowacystis  sagittaria  Thomas  and  Ladd 4 

All  views  on  this  plate  x2. 
Fig.  1.  Oral  view  of  eotype  a  attached  by  posterior  side  to  a  rock  slab.  The 
plates  of  the  lower  part  of  the  theca  are  partly  displaced  and  the  corners 
are  lost.  Note  the  radial  markings  on  the  plates,  the  protruding  part  of 
plate  0  at  the  base  of  the  arm,  the  length  of  the  median  marginal,  and 
the  dual  nature  of  the  stem.  The  upper  right  hand  plate  of  the  distal 
series  of  stem  ossicles  shows  the  contracted  part  about  which  fitted  the 
ring-like  eolunmals  of  the  distal  part  of  the  nearer  series.  Specimen  num- 
ber 3525,  8.  U.  I.  collection. 
Figs.  2-5.     Four  views  of  eotype  b,  number  352(3,  8.  U.  1. 

2.  Posterior  view  showing  position  of  plate  A.M.  and  its  relation  to 
the  other  marginals.  Note  how  far  the  marginals  extend  over  the  body 
surface.  Something  of  the  large  size  and  bilateral  symmetry  of  the  body 
plates  can  be  made  out.  Compare  the  median  plate  just  above  the  stem 
with  that  in  same  position  on  oral  side  in  figure   1. 

3.  Oral  view  showing  the  eircumoral  group  of  plates.  Many  of  the 
smaller  somatic  plates  are  lost  and  the  smooth  inner  surfaces  of  the  plates 
of  the  posterior  side  are  exposed.  The  position  of  the  thick  apical  group 
and  the  relation  of  these  plates  to  the  oral  process  is  shown.  Compare 
amount  of  stem  shown  on  the  two  sides. 

4.  Lateral  view,  oral  face  to  the  right.  Note  the  protruding  stump  of 
the  oral  process  and  the  elevated  cone  on  plate  G.  The  upright  attitude 
of  plate  A.M.  and  the  peripheral  decorations  of  the  marginals  can  be  seen. 

5.  Lateral  view,  oral  face  to  the  left.  This  side  shows  better  the  peri- 
pheral markings  of  the  marginals. 

PLATE  II 

Page 

Fig.   1.     lowacystis  sagittaria  Thomas  and  Ladd 4 

Posterior  view  of  specimen  c,  x2,  S.  U.  I.  3527.  A  small  specimen  at- 
tached to  the  matrix  when  illustrated.  Note  the  small  anal  plates  at  lower 
light  hand  corner. 

Fig.  2.     Ectenocrinns  raymondi  Slocom 12 

Natural  size,  S.  U.  I.  3770.  Anterior  view  of  a  fine  specimen  attached 
to  the  matrix. 

Figs.   3-8.     Eet<  noennits  (dengatus  Thomas  and  Ladd 10 

Fig.  3.     S.  U.  I.  3775.     A  dismembered  calyx  but  with  the  large  proximal 

stem  segments   in   place.     Note  how  the  segments  taper   distally  down  to 

the  small  ossicles  of  the  normal  stein. 

Fig.  4.     S.  IT.  I.  3771.     Right  posterior  view  of  a  nearly  complete  specimen 

showing  compound  radials.     The  proximal  stem  ossicles  are  the  largest  of 

any  in  the  collection.     This  is  the  type,  others  are  co types. 

Figs.   5,   (3.     S.   U.   I.   3772.     Right  and  posterior  views  of  a  specimen  in 

which  there  is  a  rapid  decrease  distally  in  the  size  of  the  stem  columnals. 

Fig.    7.      S.   U.   I.    3773.      Specimen    showing   partly  separated   columnals; 

basals  and  one  or  two  radials  in  position. 


PLATE  II 


15 


16 


Paoe 
Fig'.  8.     S.   LT.  I.  3774.     Left  anterior  view  of  a  small  but  well  preserved 
calyx  having  but  one  large  stem  segment. 
Figures  3-S  are  x2. 

Figs.  9-10.     Porocrinus  faycttensis  Sloeom 13 

Fig.  9.  Individual  preserving  17.5  mm.  of  the  pentagonal  stem,  composed 
of  24  segments.  The  calyx  is  partly  imbedded  in  a  dense  matrix.  Natural 
size.     8.  U.  I.  3697a. 

Figs.  10-13.  x2,  S.  U.  I.  3692.  Right,  left  posterior,  basal,  and  left  views 
of  a  calyx  from  near  Nordness.  The  first  figure  shows  the  reduced  fold- 
areas  along  the  periphery. 

Figs.  14-16.  Lot  number  3784,  S.  LT.  I.,  x4.  Separate  radial s.  Note  the 
elliptical  arm-facets,  also  the  markings. 

PLATE  III 

Page 
Figs.  1,  2,  4,  6,  7.     Carabocrinus  slocomi  cost  at  us  Foerste 14 

Figs.  3,  2  and  4.     Radial  plates  x2,  showing  the  costate  surfaces;   2  and 

4  are  partly  broken.     Figs.   6  and  7  are  outer  views  of  infrabasals   x4. 

Fig.  1  is  S.  U.  I.  3790,  2  and  4  are  in  lot  3875,  6  and  7  are  S.  U.  I.  3792a 

and  b  respectively. 
Fig.  3.     Carabocrinus  slocomi  Foerste 14 

Typical  radial  plate  x2 ;  S.  U.  I.  3781. 
Figs.  5,  8.     Pleurocystites  cf.  beckeri  Foerste 9 

Fig.  5  is  an  incomplete  thecal  plate  11,  natural  size,  S.  U.  I.  3531.     Fig.  8 

is  thecal  plate  15  or  16,  x4;  S.  II.  I.  3532. 
Fig.  9.     Ph vrocystites   clermontensis   Foerste 9 

Small  plate,  probably  4,  at  the  base  of  the  theca,  x4;  S.  LT.  I.  3533.     For 

this   and   figure   8   compare  illustrations  by  Foerste   on   plates   33   and   34, 

Iowa  Geo!.  Surv.,  vol.  NXIX. 
Figs.  10,  11.     Plates  of  unknown  crinoid 15 

Enlarged  x4;   8.  IT.  I.  3788. 
Figs.  12-14.     Ilcicrocrinus  sp.   (?) 15 

Pig.  12  is  the  proximal  part  of  a  stem,  x4;   8.   U.  I.  3783a.     Figs.  13,  14 

are  two  views  of  the  proximal  part  of  a  stem  preserving  the  lower  plates 

of  the  cup,  x2;   S.  U.  I.  3777. 
Figs.   15,  16.      Base  of  an  unknown  crinoid 15 

Basal  and  lateral  views,  x2 ;   S.  IT.  I.  3789. 
Figs.  17-22.     Undetermined   crinoid   stems 15 

Fig.  17  is  a  very  small  segment,  x4;   S.  IT.  I.  3780.     Fig.  18  is  a  segment, 

x2,   doubtfully  referred  to  Atactocrimts;    S.  U.  I.   3778.     Fig.   19   may  be 

a  bit  of  eystid  stem,  x2 ;  S.  U.  I.  3787.     Fig.  20  is  a  piece  of  thorn-angled 

stem,  x4;   8.  U.  I.  3783/;.     Fig.  21  a  long  slender  stem,  x2 :   S.  IT.  I.  3786. 
Fig.   22.     Drndrocrinus   Icayi    Sloeom 16 

Part  of  characteristic  stem,  x2 ;  S.  LT.  I.  3779. 


PLATE  III 


PLATE  IV 

Pace 
Figs.   J-(j.     Iovjacyati.s  sapiituna  Thomas  and  Ladd 4 

Fig.  1.  Posterior  view  of  specimen  d,  8.  U.  I.  collection,  no.  352S,  x2.  A 
theca  preserving  the  marginal  frame.  The  proximal  stem  ossicles  are 
much   displaced.     Anal  plates  well  shown. 

Fig.  2.  Oral  view  of  same  specimen.  Anal  plates  more  or  less  disorgan- 
ized.    Plate  G  is  in  place  but  plate  0  is  wanting. 

Figs.  3,  4.  Oral  and  posterior  sides  of  a  stem  broken  in  two  parts,  x2. 
Note  the  small  ossicles  set  among  the  longer  ones.  Compare  Plate  I,  tig 
1.  8.  U.  I.,  3529. 

Figs,  5,  (J.     Opposite  sides  of  a  piece  of  stem  showing  tendency  to  have 
three  plates  at  same  level,  x2.  8.  F.  I.,  3529. 
Fig.   7.     Rhomb-bearing    plate    of    some    unknown    evstid,    x2.    8.    U.    I.      No. 

323o ; s 

Fig.   8.     Porocri mis  fayettensis  Slocom ].;> 

Terminal  view  x2  of  a  theca  showing  the  star-shaped  peristome  and  the 
anal  opening.     8.  U.  I.  No.  3696. 

Figs.   9,  10.     Opposite  views  of  an  undetermined  erinoid   from  Fort   Atkinson. 

No.  3791.     Collected  by  H.  8.  Ladd. 
Fig.   11.     Ease  of  stem  and  roots  of  an  unknown  erinoid,  x2.     Fort  Atkinson. 

8.  U.  I.,  No.  3793.     Collected  bv  H.  8.  Ladd. 


PLATE  IV 


Of-'       i 


PLATE  V 

PAGE 

Figs.  1,  2.     Iowacystis  sagittaria  Thomas  and  Ladd 4 

Fig.  1.  Diagram  of  oral  side,  enlarged.  Drawn  chiefly  from  specimen 
b,  anal  pore  from  d.  Br,  brachial  process;  0,  oral  plate  from  which  the 
arm  arises;  G,  gonopore  plate  bearing  a  small  perforated  cone  at  its  upper 
left-hand  corner;  Y,  a  small  plate,  oblong  quadrangular  as  viewed  from 
the  right,  bearing  a  depression  in  which  lower  part  of  the  arm  rests. 
Fig.  2.  Posterior  side  showing  bilateralism.  Drawn  chiefly  from  specimen 
b,  anal  pore  from  d,  stem  from  a  separate  fragment.  A.M.  apical  mar- 
ginal; S.M.  superior  marginal;  M.M.  median  marginal;  L.M.  lower  mar- 
ginal; B.M.  basal  marginal.  Xote  that  more  of  the  proximal  series  of 
stem  ossicles  are  visible  from  this  side. 

Figs.   3,  4.     Ectcnocrirut.s  clongatm  Thomas  and  Ladd. 10 

Fig.  3.  Diagram  of  large  basal  columnals  grading  distally  into  the  normal 
stem.  Enlarged  from  specimen  3775.  Xote  the  uneven  proximal  edge  of 
the  uppermost  segment  due  to  the  shape  of  the  basals.  Compare  Plate 
II,  fig.  3. 

Fig.  4.  Analysis  of  calyx.  Xote  the  three  divided  and  the  two  undivided 
radial  s. 

Fig.  o.     Porocrinus  conicaa  Billings. 

Analysis  after  Billings,  enlarged  (see  Geol.  Surv.  Canada,  dec.  4,  1S59, 
p.  34).  The  anal  and  radianal  plates  are  vertically  ruled.  The  twenty- 
two  fold-areas  are  inserted  at  the  corners  of  the  plates.  Introduced  for 
comparison  with  fig.   7. 

Figs.   6,  7.     Powcriniui  fo.yettensis  Hlocom 13 

Fig.  (3.  From  specimen  3692.  Diagram  of  parts  of  several  plates  to  bring 
out  the  reduction  of  the  folds  in  the  peripheral  fold-areas  and  in  the  upper 
third  of  the  lower  fold-area.  Xote  the  vestigial  folds,  the  pentagon  and 
rhombs  outlined  by  the  heavy  plate  ridges  and  the  lighter  ridges  which 
bisect  each.  Sutures  are  represented  by  broken  lines.  Compare  Plate  II, 
fig.  10. 

Fig.  7.  Analysis  of  thecal  plates,  enlarged.  The  fold-areas  have  not  been 
inserted.     After  specimen   number  3692. 


PLATE  V 


e;.."j    C.'i  iti    C» 


ao/iQaa 
D/lpDn 

aw 


?8SSX>. 


PLATE  VI 


Type  exposure  of  the  Fort  Atkinson  limestone  member  of  the  Maquoketa 
shale.  Abandoned  quarry  near  the  old  blockhouse,  Fort  Atkinson,  Iowa.  Note 
even  bedding  and  chert  bands. 


Old  blockhouse  on  the  hill  above  the  Fort  Atkinson  quarrv.  Built  in  1840 
from  stone  of  the  Fort  Atkinson  member  of  the  Maquoketa.  Recently  this 
land  was  purchased  by  the  8tate,  and  the  old  buildings  are  being  repaired  with 
newly  quarried  rock. 


PLATE  VII 


.......  mmmM:m 

.. ....mmmmxz 


f 


f 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 

Henry  Frederick  Wickham,  Editor 
VOLUME  XI  NUMBER  9 

FRESH  WATER  FAUNA  OF  IOWA 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY,  IOWA 


CONTENTS 


A  Study  of  Tritogonia  tuberculata,  the 

Pistol-Grip  Mussel  David  T.  Jones 

Ecological  Studies  of  the  Short-Nosed  Oar-Pike 

(Lepidosteus  platystomus)  George  E.  Potter 

Water  Mites  of  the  Okoboji  Region  Ruth  Marshall 


A  STUDY  OF  TRITOGONIA  TUBERCULATA, 
THE  PISTOL-GRiP  MUSSEL 

David  T.  Jones 

The  incentive  to  study  certain  animals  comes,  not  because  of 
their  utility,  but  because  their  uniqueness  arouses  curiosity.  The 
blade-beaked  skimmers  (Rhynehopidae),  duck-billed  platypus  (Or- 
nithorkynchus) ,  the  dog's  head  butterfly  (Zerene  cwsonia)  are 
familiar  examples.  Among  mollusks,  the  buckhorn  or  pistol-grip, 
Tritogoma  tubercvlata  (Barnes),  likewise  never  fails  to  arouse 
curiosity.  Children  wonder  ''what  is  the  matter  with  it"  and 
usually  regard  it  as  a  freak.  The  noticeable  feature  about  the 
shell  is  the  surface,  studded  with  protuberances  which  makes  the 
name  "  pistol-grip"  applicable.  Call  speaks  of  the  surface  as 
"nodulous,"  while  Baker  calls  the  prominences  "tear-like  pus- 
tules." Simpson1  regarded  this  shell  as  peculiar  enough  to  merit 
a  separate  genus  Tritogonia.  Ortmann*  thinks  it  resembles  the 
Quadrulas  enough  in  internal  anatomy  to  be  called  Quadrula  tuber- 
cvlata (Barnes).  As  to  the  pustulate  surface,  he  calls  attention 
to  the  fact  that  Quadrvla  lachrymosa  (Lea),  the  maple-leaf  is 
scarcely  less  pustulose.  Walker,3  however,  as  late  as  1918,  is 
content  to  Let  it  remain  aloof  in  its  own  genus  Tritogonia. 

Simpson  gives  two  species  and  one  variety  of  Tritogoma  for 
the  United  States.  In  distribution  Tritogonia  tubercvlata  is  con- 
fined to  the  Mississippi  Valley  and  Gulf  drainages.  Call4  gives 
its  range  as  "Western  New  York  to  Minnesota,  Iowa  and  Nebraska; 
to  Kansas  and  central  Texas;  to  Georgia  and  Alabama.  The 
species  was  originally  described  from  Wisconsin."  In  most  older 
works  it  goes  under  the  name  TJnio  tuberculatum  (Barnes),  which 
name  dates  from  1823. 

Economic  reports  on  Tritogonia  tubercvlata  for  the  most  part 
consider  it  along  with  other  shells.    It  is  used  to  a  certain  extent 

i  Synopsis  of  the  Naiades,  p.  608. 

2  Families  and  Genera  of  the  Najades,  p.  254. 

a  A  Synopsis  of  the  Classification  of  the  Fresh  Water  Mollusca  of  North 
America,  p.  45. 

*  The  Unionidse  of  Arkansas,  p.  55. 

3 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

in  the  pearl-button  industry.  Coker5  reports  it  as  having  "  white 
nacre  of  good  texture  and  quality,  but  is  often  spotted.  It  is 
thinnish  at  the  tip  and  has  a  very  rough  back;  some  shells  have 
a  pinkish  tinge. "  Baker6  reports  that  the  Salt  Fork  and  Sangamon 
species  (Illinois)  are  of  good  quality  for  buttons,  and  calls  atten- 
tion to  the  fact  that  "abnormalities  and  pearly  growths  due  to 
injuries  or  parasitism  are  rare  in  specimens  of  this  species  exam- 
ined. ' ?  Call  reports  the  nacre  as  usually  white,  but  often  blotched 
in  large  specimens  with  irregularly  distributed,  brownish  spots. 
He  says  that  more  than  half  the  specimens  from  the  Cahaba  River, 
Alabama,  have  purple  nacre. 

The  following  extracts  from  descriptions  bring  out  the  main 
features  of  the  shell  and  animal. 

Ward  and  Whipple7 — "All  four  gills  serving  as  marsupia.  Shell 
large,  solid,  rhomboid,  truncated  posteriorly  in  the  male,  elongated 
with  a  strong  posterior  ridge,  sexes  dissimilar  in  shape,  the  poster- 
ior region  being  rounded  or  subcompressed  in  the  female;  hinge 
complete,  surface  pustulose,  except  on  the  extended  portion  of 
the  female/'  Walker — "Epidermis  dark  olive,  hinge  plate  rather 
narrow ;  pseudocardinals  strong,  rugged ;  laterals  long  and  straight, 
near  to  the  pseudocardinals. ' '     Simpson — "Well  developed  lunule 

filled  with  epidermal  matter Inner  gills  much  larger    than 

outer,  generally  free  from  abdominal  sac. " 

The  periostracum  is  thin  and  tough,  not  scaling  readily;  the 
prismatic  layer  thin,  and  the  nacreous  layer  thick.  All  three 
layers  enter  into  the  composition  of  the  nodules.  On  the  inside 
of  the  shell  the  nacre  is  smooth  showing  no  conformity  to  the 
rough  exterior  except  slight  undulations  in  the  posterior  region, 
and  an  arched  furrow  corresponding  to  the  umbonal  ridge.  The 
latter  is  sometimes  so  great  as  to  pull  the  mantle  away  from  the 
shell,  thus  breaking  the  pallia!  line  as  in  fig.  3.  The  nodules  are 
irregular,  but  often  elongate  and  pointed  radially  in  the  opposite 
direction  from  the  beak.  Back  of  the  posterior  umbonal  ridge 
especially  of  the  short  shells,  the  nodules  are  extremely  large  and 
united  in  huge  folds. 

A  good  start  has  been  made  on  the  ecology  of  Tritogonia  tuber- 
culata  in  the  Fisheries  Bureau  Report  on  "Natural  History  and 


s  Fresh-water  Mussels  and  Mussel  Industries,  p.  27. 

6  Fauna  of  the  Big  Vermillion  River,  p.  33. 

7  Fresh  Water  Biology,  p.  998. 


THE  PISTOL-GRIP  MUSSEL  5 

Propagation  of  Fresh-Water  Mussels8.' '  There  Tritogonia  tuber- 
culata  is  recorded  as  being  found  in  sand,  sand  and  gravel,  gravel, 
mud;  and  sand,  soft  mud  over  firm  bottom,  mud,  and  clay  and  sanid. 
Authorities  disagree  as  to  which  kind  of  bottom  Tritogonia  tuber- 
culata  prefers,  some  believing  "mud"  or  "mud  over  firm  bottom", 
while  others  believe  "gravel".  Drew9  records  it  as  common,  es- 
pecially on  muddy  bottoms.  Baker  found  the  largest  specimens 
"on  a  mud  bottom  although  it  also  lives  on  sand  and  gravel 
bottom."  The  specimens  on  which  this  article  is  based  were  brought 
up  by  the  sand  pump  from  the  sand  bed  in  Iowa  River  just  south 
of  Benton  Street  bridge  at  Iowa  City,  Iowa.  Somewhere  in  the 
neighborhood  of  fifteen  specimens  were  secured  during  the  period 
from  September  through  December,  1925.  When  rock  and  gravel 
were  pumped  up  with  the  sand  they  seemed  to  be  the  most  plen- 
tiful. They  were  thrown  out  very  irregularly,  more  than  half 
the  number  being  secured  on  two  days  between  which)  several  weeks 
intervened.  As  the  intake  of  the  sand  pump  was  swinging  across 
the  river  in  ever-lengthening  arcs,  this  would  hint  at  gregarious- 
ness.  Single  specimens  were  secured  while  the  pumping  was  con- 
fined to  the  middle  of  the  stream,  but  the  two  groups  were  struck 
when  pumping  was  approaching  shore,  yet  in  deep  water  and 
current.  Coker,  Shira,  and  co-workers  record  Tritogonm  tuber- 
culoma as  occuring  in  little  or  no  current,  fair  or  good  current,  and 
strong  or  swift  current.  Two  authorities  think  it  prefers  the 
second  situation;  one,  the  last.  While  Tritogonia  tuber  culata  seems 
to  prefer  a  current,  it  can  live  in  still  water.  Of  the  group  on 
which  this  article  is  based,  one  was  kept  alive  from  the  latter  part 
of  September  to  the  first  of  the  following  December  in  a  vessel  in 
which  the  water  was  changed  once  a  day  or  once  in  two  days. 
Tritogonia  tuberculata  outlived  other  species  (Quadrula  plicata, 
Q.  pustulosa,  and  Lampsilis  gracilis)  kept  under  similar  conditions. 
Of  the  other  forms  Quadrula  plicata  seemed  to  approach  the  en- 
durance of  Tritogonia  tuberculata. 

As  this  study  was  made  in  the  fall  there  was  no  opportunity  to 
observe  glochidia  for  Tritogonia  tuberculata  is  a  summer  breeder.10 
Simpson,  quoting  Kelly,  in  "Synopsis  of  the  Najades"  says  that 

s  Coker,  Shira,  Clark,  and  Howard,  p.  106. 
s  Unios  of  Iowa,  Vol.  2. 

io  Coker  and  others.  Natural  History  and  Propagation  of  Fresh  Water 
Mussels. 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  form  with  the  compressed  shell,  having  the  expanded  nap 
behind,  is  the  female.  Very  little  seems  to  be  known  of  the  life 
history  of  this  species.  Coker,  Shira,  and  associates  give  an  illus- 
tration of  a  glochidium,  and  observed  the  growth  made  by  a  med- 
ium sized  specimen  from  July  31,  1911  to  Nov.  14,  1913  during 
which  there  was  an  increase  in  length  of  0.36  inch.  Baker,  in  Salt 
Fork  at  Homer  Park,  111.,  found  large  males  115  mm.  long  and 
females  145  mm.  long,  together  with  young  specimens  46  mm.  long. 
Tritogonia  tuberculata  has  been  and  is  yet  reported  as)  common  in 
regard  to  numbers  throughout  its  range.  In  the  region  of  Iowa 
City  the  following  are  the  most  common  mussels  in  the  order  of 
their  abundance,  judging  from  what  the  sand  pumps  throw  up 
and  from  the  shell  piles  along  the  shore. 

1.  Quadrula  plicata    (Q.   undulata  is  less  common  than  Q. 
plicata  and  is  usually  not  distinguished  from  it.) 

2.  Symphynota  complanata 

3.  Lampsilis  gracilis 

4.  Lampsilis  ligamentina 

5.  Anodonta  grandis 

6.  Quadrula  pustulosa 

7.  Tritogonia  tuberculata 

8.  Lampsilis  ventricosa 

9.  Lampsilis  anodontoides 

10.  Obliquaria  renexa 

11.  Plagiola  donaciformis 

12.  Lampsilis  alata 

13.  Quadrula  trigona 

14.  Lampsilis  capax 

15.  Pleurobema  gesopus 

16.  Quadrula  coccinea 

17.  Lampsilis  recta — 1  live  specimen  and  1  valve  found 

18.  Quadrula  metanevra — 1  specimen — Coralville 

19.  Lampsilis  subrostrata — 1  specimen — near  Amana 

20.  Quadrula  ebenus — 1  valve 

21.  Quadrula  laehrymosa? — 1  valve. 

The  following  living  mussels  were  thrown  out  of  the  same  sand 
bed  where  the  specimens  of  Tritogonia  tuberculata  were  secured. 
These  are  given  in  the  order  of  their  abundance. 

1.  Quadrula  plicata 

2.  Lampsilis  gracilis 


THE  PISTOL-GRIP  MUSSEL  7 

3.  Anodonta  grandis 

4.  Quadrula  pustulosa 

5.  Tritogonia  tuberculata 

6.  Lampsilis  anodontoides 

7.  Quadrula  trigona — 1  specimen 

8.  Pleurobema  aesopus — 1  specimen. 

9.  Symphynota  complanata — 1  specimen. 
10.  Lampsilis  recta — 1  specimen. 

Shimek's  ''Keys  to  the  Mollusca  of  Iowa"  were  used  in  classifica- 
tion. Drew's  "Unios  of  Iowa"  Vol.  2,  Coker's  "Freshwater  mussels 
and  the  mussel  industries  of  the  United  States"  and  other  articles 
were  used  as  checks  on  identification. 

I  wish  to  thank  Dr.  Gilbert  L.  Houser  and  Dr.  Frank  A.  Strom- 
sten  for  the  facilities  provided  in  the  laboratories  of  Animal  Bi- 
ology of  the  State  University  of  Iowa  where  this  study  was  made, 
as  well  as  for  the  helpful  suggestions  offered. 

Tissues  for  sectioning11  were  fixed  in  Bouin's  picro-formol,  Car- 
noy's  fluid,  Chrom-aceto-formaldehyde,12  and  Chrom-oxalic  acid.13 
The  paraffin  method  for  delicate  objects  was  used.  All  sections 
were  cut  10  micra  thick  except  one  thick  free-hand  section  through 
the  edge  of  the  mantle  to  show  the  calcareous  bodies  in  the  connec- 
tive tissue.  For  a  detailed  study  of  cell  structure  it  would  be 
better  to  cut  still  thinner.  Sections  through  the  visceral  mass  were 
floated  out  in  warm  water  immediately  after  cutting  to  prevent 
curling.  Delafield's  hematoxylin  and  erythrosin  were  used  as  stains, 
although  mucin  tests  were  made  with  thioniii  also.  The  calcareous 
nature  of  structures  was  tested  by  adding  glacial  acetic  acid  to 
freshly-stained  sections  and  observing  changes  under  the  low  power 
of  the  compound  microscope.    Permanent  sections  were  cleared  in 


ii  See  Guyer  for  technique  unless  specifically  stated. 

12  Formula  used  in  Laboratories  of  Animal  Biology,  S.  U.  I. 

Chromic  Acid,  1%  640  cc. 

Glacial  Acetic  40  cc. 

Pure  Formaldehyde  320  cc. 


1000  cc. 
Wash  out  in  water. 
13  Formula  used  in  Laboratories  of  Animal  Biology,  S.  U.  I. 
Oxalic  Acid,  8%  aq.  sol.  800  cc. 

95%  Alcohol  600  cc. 

Chromic  Acid,  1%  aq.  sol.  600  cc. 


2000  cc. 
Mix  in  the  order  as  named. 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

xylol  and  mounted  in  balsam.  Outlines  of  drawings  of  microscopic 
sections,  except  figures  8,  9,  14,  and  21  were  made  by  the  aid  of 
the  projecting  microscope.  Figures  8,  9,  and  14  were  made  under 
oil  immersion. 

The  ligament  in  Tritogonia  tubercvlata  extends  from  the  beaks 
posteriorly  about  half  the  length  of  the  hinge  teeth.  It  is  low, 
usually  not  rising  above  the  level  of  the  dorsal  part  of  the  valves. 
Anterior  and  posterior  to  the  ligament  lie  the  anterior  and  poster- 
ior lunuLes  respectively.  The  former  has  more  epidermal  matter 
and  is  better  developed.  Both  lunules  and  the  ligament  have  a 
heavy  outer  layer  corresponding  to  the  periostracum  of  the  valves. 

The  interior  of  each  valve,  if  normal,  is  a  mirror-image  of  the 
other,  except  for  the  teeth.  The  cardinal  teeth,  normally  two  in 
each  valve,  are  large  and  jagged,  the  most  anterior  cardinal  in 
the  left  valve  being  usually  largest.  The  broad,  smooth,  flattened 
junction  between  the  cardinals  and  hinge  teeth  is  well  developed 
in  both  valves.  On  the  right  valve  it  frequently  bears  a  rudimen- 
tary third  cardinal.  There  are  two  hinge  teeth  in  the  left  valve 
and  one  tooth  in  the  right.  Of  the  former,  the  ventral  tooth  is 
usually  highest  in  its  posterior  extent.  The  hinge  teeth  are  quite 
straight  but  do  not  run  parallel  with  the  dorsal  border  of  the  shell. 

Both  anterior  and  posterior  adductor  scars  are  well  impressed, 
the  former  being  deeper.  Continuous  with  its  inner  border  is 
the  scar  of  the  anterior  retractor  pedis.  The  impression  of  the 
protractor  pedis,  immediately  posterior  to  the  anterior  adductor, 
is  especially  deep.  The  posterior  retractor  pedis  scar,  near  the 
dorso-anterior  border  of  the  posterior  adductor,  is  very  superficial. 

The  pallial  line  normally  extends  from  the  lower  outer  portion 
of  the  anterior  adductor  scar  around  to  the  outer  border  of  the 
posterior  adductor  sear.  It  does  not  run  parallel  to  the  border, 
especially  in  the  posterior  part,  but  continues  its  oval  course 
without  following  the  posterior  bulge  of  the  margin.  Some  mantle 
vessel,  probably  the  peripheral  artery  of  the  mantle,  has  impressed 
a  groove  in  the  nacre,  starting  where  the  pallial  line  meets  the 
anterior  adductor  scar,  then  curving  outward  and  running  posteri- 
orly close  to  and  parallel  with  the  margin  of  the  valve.  This 
groove  becomes  fainter  as  it  proceeds  posteriorly.  A  slight  pearly 
ridge,  obliquely  dorsal  to  the  depression  which  corresponds  to  the 
umbonal  ridge  is  noticeable  in  some  shells. 

The  mantle  closely  invests  the  inner  surface  of  each  valve.     It 


THE  PISTOL-GRIP  MUSSEL  9 

is  attached  at  the  muscle  sears  by  the  piercing  strands  of  the 
muscles,  and  at  the  pallial  line  also  by  muscular  strands.  The 
mantle  is  thin  and  barely  transparent  except  the  portion  distal  to 
the  pallial  attachment,  which  forms  a  thickened  muscular  edge.  The 
right  and  left  lobes  of  the  mantle  are  fastened  together  between 
the  two  siphons  in  the  region  of  the  posterior  termination  of  the 
gills.  At  the  exhalant  siphon  there  is  little  modification  of  the 
mantle,  but  at  the  inhalant  the  margin  is  much  thickened,  and  the 
inner  part  is  modified  into  papillae,  called  siphonal  tentacles  or 
fimbriae.  These  are  most  robust  near  the  center  of  the  siphonal 
opening.  There  are  from  seven  to  fourteen  large  fimbriae  on  each 
side  of  the  siphon  and  twice  that  many  small  ones.  The  two  lobes 
of  the  mantle  meet  near  the  posterior  ends  of  the  hinge  teeth.  A 
thickened  fold  of  the  mantle  (fig.  4x)  lying  dorsal  to  the  hinge 
teeth  continues  as  thin  sheets  over  the  hinge  teeth  of  both  right 
and  left  valves.  Between  the  bases  of  the  cardinal  teeth  the  mantle 
is  thickened,  and  again  becomes  very  thin  over  the  jagged  portion 
of  the  cardinals. 

The  function  of  the  mantle  in  seeretingj  the  shell  is  an  interesting 
study.  The  edge  of  the  mantle  is  modified,  not  only  at  the  inhalant 
siphon,  but  to  the  lesser  degree  all  around.  In  cross-section  it 
shows  an  outer,  a  middle,  and  an  inner  lobe  (fig.  11).  The  peri- 
ostracum  is  secreted  from  a  groove  at  the  junction  of  the  outer 
and  middle  lobes.  This  groove  is  lined  ventrally  by  a  mound  of 
tall  columnar  epithelium  and  dorsally  by  cuboidal  epithelium  (fig. 
13).  The  periostracum  seems  to  come  off  of  the  latter  as  a  secre- 
tion. The  cells  of  this  groove  are  not  pigmented  as  is  the  neighbor- 
ing epithelium.  This  apparatus  makes  an  excellent  histological 
study.  Without  using  a  lens  the  periostracum  can  be  seen  stretch- 
ing over  the  outer  fold  to  the  edge  of  the  valve,  in  specimens 
where  the  mantle  has  been  undisturbed.  The  origin  of  the  pris- 
matic layer  and  nacreous  layer  is  not  so  evident.  Since  the  peri- 
ostracum is  the  outer  layer,  and  is  laid  down  first,  the  other  two 
layers  would  have  to  be  formed  by  the  outer  lobe  of  the  edge  or 
the  outer  epithelium  of  the  mantle.  No  histological  evidence  was 
found  as  to  the  origin  of  these  two.  Parker  and  Haswell  make 
the  statement  that  the  prismatic  coat  is  also  formed  by  the  edge 
of  the  mantle  and  the  nacreous  coat  by  the  whole  outer  surface  of 
the  mantle.  The  outer  epithelium  consists  of  tall  columnar  epithe- 
lial cells  (fig.  14)  resting  on  a  homogeneous  basement  membrane 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

under  which  are  the  muscle  cells  and  connective  tissue.  The  inner 
epithelium  is  similar  but  contains  more  mucous  cells,  many  of 
which  are  subepithelial  (fig.  12).  The  inner  lobe  of  the  edge  of 
the  mantle  contains  much  amorphous  material  which  stains  blue 
with  hematoxylin.  In  the  middle,  connective-tissue  layer  of  the 
mantle,  large  masses  of  granules  calcareous  in  nature  were  found. 
These  disintegrate  least  in  thick  sections. 

A  process,  no  less  interesting  than  the  activities  of  the  mantle 
edge,  is  going  forward  in  the  region,  of  the  hinge  teeth  and  cardinal 
teeth.  Drew,  in  "Unios  of  Iowa",  Vol.  1,  gives  sections  through 
the  teeth,  showing  the  undulating  layers  of  nacre  deposited  by 
the  mantle.  Coker  and  co-workers,  ini  "Natural  History  and  Pro- 
pagation of  Fresh-Water  Mussels",  say  that  hypostracum  is  laid 
down  by  the  ends  of  the  muscles  in  place  of  nacre.  Since  the 
muscles  retain  the  same  relative  position  on  the  shell  during  the 
life  of  the  animal  they  must  migrate  to  keep  up  with  shell  growth. 
Thus  a  layer  of  hypostracum  extends  in  a  tapering  vein  through 
the  nacre  from  the  beak  to  each  muscle  scar  and  to  the  pallial  line. 
Considering  the  process  of  enlargement  of  the  teeth  by  the  mantle 
as  going  forward  over  these  earlier  deposits  of  hypostracum,  the 
explanation  of  the  growth  of  this  part  of  the  shell  becomes  as 
interesting  as  the  marginal  growth.  It  is  interesting  to  note  that 
the  thickest  part  of  the  mantle,  which  is  in  the  region  of  the 
inhalant  siphon,  produces  the  thinnest  part  of  the  shell.  A  fold 
of  the  mantle,  covering  the  anterior  ends  of  the  gills  and  the  liver, 
is  contained  in  the  umbonal  cavity  which  in  Tritogonia  tuberculata 
lies  under  the  flattened  junction  of  cardinal  and  hinge  teeth. 

The  outer  gills  are  attached  to  the  mantle.  Keber's  organ,  a 
light  brown  body,  lies  along  the  mantle  dorsal  to  the  junction.  The 
gills  are  generally  considered  as  modified  folds  of  the  mantle. 
There  are  four  gills,  one  pair  on  each  side  of  the  central,  visceral 
mass.  The  outer  gill  in  Tritogonia  tuberculata  is  much  shorter,  than 
the  inner  one,  as  shown  in,  fig.  5.  Each  gill  is  composed  of  two 
lamellge  with  an  intervening  series  of  water  tubes.  The  lamellae 
are  connected  by  interlamellar  junctions  between  water  tubes. 
Each  lamella  is  finely  striated  vertically  on  its  outer  surface  by 
ridges  and  grooves.  These  ridges  are  the  gill  filaments.  There 
are  ten,  to  the  millimeter  in  one  specimen  studied.  In  this  speci- 
men, interlamellar  junctions  showed  through  the  lamella  so  they 
could  be  counted  from  the  outside.    There  were  twelve  of  these  to 


THE  PISTOL-GRIP  MUSSEL  11 

one  centimeter.  Fig.  17  shows  a  cross  section  of  the  dorsal  portion 
of  the  gills.  The  filaments  cut  in  section  are  margined  with 
ciliated  epithelium.  Spaces,  called  ostia,  open  between  filaments 
and  communicate  with  the  water  tubes.  Thus  water,  admitted 
through  the  inhalant  siphon,  circulates  from  the  mantle  cavity 
through  the  ostia,  through  water  tubes,  to  super-branchial  chamber, 
and  out  at  the  exhalant  siphon.  Through  the  substance  of  the 
lamella  and  interlamellar  junctions  run  many  blood  vessels. 
Schwanecke,  in  1913,  worked  out  the  relations  of  these  vessels 
in  Anodonta.  He  finds  that  the  venous  net  or  reticulum  lies 
vertically  near  the  outer  edge  of  the  lamella  and  extends  into  each 
gill  filament.  The  arterial  net  is  represented  by  a  vertical  network 
of  vessels  near  the  water  tubes.  Between  these  two  nets  there  are 
connectives.  The  larger  arteries  come  in  through  the  interlamellar 
junctions.  Supporting  rods  are  found  in  the  filaments.  In  the 
dorsal  portion  of  the  gill,  mucous  material  was  found.  Masses  of 
mucous  material  seem  quite  common  in  the  mantle  and  certain 
parts  of  the  body.  Sometimes  they  are  amorphous,  sometimes 
goblet  cells,  or  long  subepithelial  mucous  cells.  The  last  case  is 
best  illustrated  in  the  longj  subepithelial  mucous  cells  in  the  ventral 
portion  of  the  foot  (fig.  16). 

The  visceral  mass  consists  of  two  parts ; — the  visceral  mass  proper 
and  the  muscular  foot  which  curves  over  the  visceral  mass  ven- 
trally  and  anteriorly.  The  foot  in  the  Tritogonia  tuberculata  is 
narrower  and  projects  more  anteriorly  than  the  foot  in  mussels 
of  the  LampsiUis  type.  A  specimen  kept  in  an  aquarium  quickly 
buried  itself  in  the  sand  on  the  bottom  when  the  water  became 
stagnant,  instead  of  pulling  itself  over  the  surface  as  Lampdlis 
gracilis  and  Quadrvla  plieata  did.  The  foot  in  Tritogoma  tubercu- 
lata  seems  to  be  very  efficient,  although  it  is  less  frequently  pro- 
truded than  in  the  Quadrulas.  Above  the  foot  is  the  visceral 
mass  proper  which  in  cross-section  projects  downward  in  longi- 
tudinal midline  into  the  foot  (fig.  21).  Transverse  muscles  pass 
through  the  visceral  mass  from  the  muscles  of  the  foot  on  one  side 
to  those  on  the  other.  Most  of  the  visceral  mass  proper  is  composed 
of  reproductive  organs  which  give  it  a  spongy  appearance.  In 
the  visceral  mass  are  imbedded  parts  of  other  systems  as  described 
below.  Dorsal  to  the  visceral  mass  lie  the  organs  of  Bojanus, 
kidneys  or  nephridia,  two  tubes  one  on  each  side  consisting  of 
a  ventral  glandular  and  smooth  dorsal  portion.     They  lie  just 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

dorsal  to  the  internal  gill  and  lower,  more  internal,  and  more 
posterior  than  Keber's  organs  (fig.  4).  A  section  through  the 
folds  of  the  glandular  portion  (fig.  15)  shows  that  these  folds  are 
made  up  of  a  single  layer  of  columnar  epithelium,  beneath  which 
is  a  thin  layer  of  connective  tissue.  Under  this  are  large  spaces 
containing  many  leucocytes. 

Dorsal  to  the  organs  of  Bojanus,  and  in  midline,  is  the  heart, 
composed  of  a  tubular  ventricle  and  two  flaplike  auricles  (fig.  4). 
The  ventricle  is  folded  around  the  rectum,  thus  enclosing  it.  The 
pericardium  (fig.  5)  covers  this  organ  loosely  leaving  a  large  peri- 
cardial space. 

The  nervous  system  consists  of  three  pairs  of  ganglia.  In 
Tritogonia  tiiberadata  the  nervous  system  is  white.  In  two  of  the 
species  dissected,  namely  Symphynota  complanata  and  Pleurobema 
cesopus,  this  system  had  a  salmon  colored  tinge  which  set  it  off 
markedly  from  the  surrounding  tissues  and  facilitated  dissection. 
In  Tritogonia  tuberculata  the  cerebral  ganglia  lie  on  the  ventro- 
posterior  surface  of  the  anterior  adductor  muscle,  the  visceral 
ganglia  on  the  ventral  surface  of  the  posterior  adductor,  and  the 
pedal  ganglia  in  the  muscles  of  the  anterior  foot  region  in  midline 
near  the  junction  of  the  visceral  mass  proper  with  the  muscles 
of  the  foot  (fig.  4).  The  first  two  pairs  are  connected  by  commis- 
sures (fig.  21)  and  the  pedal  are  connected  to  the  cerebral  ganglia 
by  commissures.  In  a  cross-section  through  the  pedal  ganglia 
and  anterior  foot  region,  the  nerve  cells  were  torn  apart  in  sec- 
tioning by  transparent,  elongate  capsules,  wThich  wTere  themselves 
shattered  by  the  razor.  Some  of  these  contained  coarse,  gran- 
ular bodies  which  stained  deep  blue  with  hematoxylin.  These 
parasitic  sporocysts  (fig.  9)  seemed  to  be  confined  to  the  ganglia 
as  the  surrounding  muscles  were  free  of  them.  Except  for  lacking 
the  long  flattened  tail,  they  resemble  the  sporocysts  of  gregarines 
which  Helen  P.  Goodrich  illustrated  in  a  recent  number  of  the 
Quarterly  Journal  of  Microscopical  Science.14 

The  labial  palps  are  four  in  number  and  lie  one  pair  on  each 
side  of  the  visceral  mass.  They  are  joined  dorsally  for  a  greater 
part  of  their  length.  The  approximated  sides  of  labial  palps  are  fur- 
rowed vertically  by  lateral  furrows  (figs.  6,  7,  and  10).  These  fur- 
rows and  the  ridges  between  are  lined  with  columnar,   ciliated 


14  Quarterly  Journal  of  Microscopical  Science.    Vol.  69,  Part  IV,  Oct.  1925, 
Plate  49,  page  628,  fig.  10. 


THE  PISTOL-GRIP  MUSSEL  13 

epithelium  which  rests  on  connective  tissue.  Grooves  project  into 
the  ridges  on  either  side  of  the  furrows.  These  grooves  are  very 
regularly  arranged  in  Tritogonia  tuberculoma.  Many  blood  vessels 
run  through  the  connective  tissue  of  the  palp.  The  outer  epithe- 
lium rests  on  a  heavy  basement  membrane  of  homogeneous  struc- 
ture. The  labial  palps  are  united  and  fastened  to  the  visceral 
mass  for  about  one-half  their  length  as  shown  in  figure  5.  However, 
the  labial  palps  are  joined  together  posterior  to  this  and  are 
attached  to  the  mantle  for  about  five-sixths  of  their  length,  the 
posterior  one-sixth  being  free.  In  this  region,  where  they  are 
joined  to  the  mantle  but  not  to  the  visceral  mass,  there  is  a 
distinct  dorsal  furrow  which  extends  dorsally  to  the  ventral 
margin  of  the  inner  gill.  This  furrow  is  lined  with  columnar 
epithelium  (fig.  8)  which  has  very  large  cilia.  Many  goblet  cells 
also  occur  in  this  region.  The  two  pairs  of  labial  palps  meet  at 
the  mouth,  thus  forming  upper  and  lower  lips. 

The  mouth  opening  is  small.  It  leads  into  a  short  esophagus 
which  gradually  enlarges  and  opens  to  the  right  into  a  sac-like 
stomach  which  continues  as  a  blind  pouch  anteriorly.  Both  esopha- 
gus and  the  stomach  are  surrounded  by  the  liver.  The  intestine 
leads  obliquely,  from  the  ventral  part  of  the  stomach,  in  a  U-shaped 
loop  ventro-posteriorly  through  the  mass  of  reproductive  organs  to 
the  ventral  part  of  the  visceral  mass  proper,  then  curving  dorsally 
to  the  postero-dorsal  portion  of  the  visceral  mass.  This  U-shaped 
portion  is  sometimes  called  the  crystalline  style  portion,  as  under 
certain  conditions  it  contains  the  crystalline  style.  From  here  the 
intestine  bends  sharply  on  itself,  curving  to  the  right  and  posteri- 
orly. It  descends  parallel  to  the  ascending  ramus  of  the  U  until 
it  reaches  the  most  ventral  portion  of  the  visceral  mass;  thence  it 
continues  anteriorly  along  the  ventral  margin  of  the  visceral  mass 
until  under  the  stomach,  then  curves  sharply  on  itself,  turning  to 
the  right  and  running  posteriorly,  crossing  to  the  right  of  the  de- 
scending ramus  of  the  U.  This  part  is  known  as  the  thin-walled 
portion.  After  crossing  to  the  right  it  curves  between  the  two 
rami  of  the  U  as  the  rectum,  and  passes  into  the  pericardium  and 
the  ventricle  of  the  heart  where  it  takes  a  horizontal  course  poster- 
iorly, finally  running  dorsal  to  the  posterior  adductor  and  termi- 
nating in  the  anus  which  is  bordered  by  scalloped  folds.  Starting 
in  the  last  ascent  of  the  intestine,  or  in  the  rectum,  is  a  ventral 
fold,  the  typhlosole.    The  intestine  is  small  in  the  crystalline  style 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

portion.  The  thin-walled  portion  and  rectum  are  much  more 
enlarged.  The  coiling  of  the  intestine  is  remarkably  uniform  in 
the  different  species  of  mussels  examined.  Variations  were  noted 
in  Tritogonia  tuberculata  in  the  anterior  extent  of  the  intestine  in 
the  ventral  portion  of  the  visceral  mass,  and  in  the  nearness  of 
approach  to  the  stomach  of  the  typhlosolic  portion  of  the  rectum 

(fig.  4). 

A  cross-section  of  the  rectum  in  the  region  of  the  ventricle  (fig. 
20)  shows  an  inner  lining  of  ciliated,  columnar  epithelium  with 
many  goblet  cells.  The  typhlosole  is  composed  of  connective  tissue. 
The  basement  membrane  of  the  epithelium  is  most  pronounced 
here. 

The  liver,  greenish  in  color,  closely  surrounds  the  esophagus 
and  stomach  and  extends  dorsally  with  the  anterior  portion  of  the 
gills  into  that  fold  of  the  mantle  which  goes  into  the  beak  of  the 
shell  (fig.  4).  It  is  a  compound  tubular  gland  as  shown  by  cross- 
section  (fig.  18).  The  larger  ducts  are  lined  by  folded  epithelium 
composed  of  slender,  ciliated,  columnar  cells  and  goblet  cells.  Some 
of  these  folds  are  caused  by  actual  folding  while  others  are  formed 
by  elongation  of  the  cells.  The  tubes  are  lined  with  secreting 
epithelium,  composed  of  large  cuboidal  or  columnar  cells. 

Tritogonia  tuberculata  structurally  presents  a  peculiar  shell, 
some  peculiarities  of  the  gills,  and  a  narrower  and  more  anteriorly 
projecting,  blade-like  foot  than  most  freshwater  mussels.  It  is 
hardy,  it  can  endure  still  water,  and  is  of  some  economic  value. 
This  combination  recommends  further  investigation  of  its  life  his- 
tory from  the  viewpoint  of  mussel  culture.  Dr.  Frank  A» 
Stromsten  suggests  that  an  investigation  of  the  correlation  between 
lime  content  of  water  and  type  of  shell  might  be  well  worth  while 
in  the  transplantation  of  mussels.  It  would  be  interesting  to  have 
data  from  certain  parts  of  Iowa  where  streams  flow  over  relatively 
little  limestone,  and  then  similar  data  from  limestone  regions  of 
our  state,  and  notice  the  difference  in  thickness  and  texture  of 
the  shells  of  mussels  from  the  two  areas.  Professor  Shimek  finds 
snail  collecting  better  in  limestone  regions  than  in  sand  dune  areas> 
even  though  the  latter  be  wooded.  Some  similar  correlation  might 
be  found  in  mussel  distribution.  Mr.  George  Potter  brought  some 
mussels  from  the  Okoboji  and  Little  Sioux  regions,  an  area;  of  com- 
paratively little  limestone  and  near  the  headwaters  of  the  drainage 
systems.     I  notice  that  his  specimens  of  Symphynwta  compkmata 


THE  PISTOL-GRIP  MUSSEL  15 

are  much  more  fragile  than  those  we  find  here  in  the  Iowa  River. 
The  number  of  species  varies  with  different  localities,  and  the 
individuals  of  one  species  vary  likewise  with  locality.  The  whole 
question  is  one  that  calls  for  data  which  could  be  collected  easily, 

BIBLIOGRAPHY 

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16  IOWA  STUDIES  IN  NATURAL  HISTORY 

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Vol.  7,  No.  2,  p.  75  and  p.  80. 
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PLATES 


PLATE  I 

Key  to  figure  1.    Elongate  form  of  Tritogonia  tuberculata 

u.        umbo 

u.r.     umbonal  ridge 

p.        pustule 

l.g.     line  of  growth 
Key  to  figure  2.     Short  form  of  Tritogonia  tuberculata 

1.        ligament 


PLATE  I 


^ 


PLATE  II 

Key  to  figure  3.     Interior  of  valves.     Tritogonia  tiiberculata 

p.  pallial  line 

p.p.  protractor  pedis  scar 

a.r.  anterior  retractor  pedis  scar 

r.p.  posterior  retractor  pedis  scar 

p.a.  posterior  adductor  scar 

a.a.  anterior  adductor  scar 
b.p.l.  break  in  pallial  line 

x.  groove  probably  representing  peripheral  artery  of  mantle 

1.  ligament 

p.l.  posterior  lunule 

a.l.  anterior  lunule 

b.  beak 

c.  cardinal  teeth 
h.  hinge  teeth 

Key  to  figure  4.    Conventionalized  section  through  visceral  mass  in  right  valve 

li.  liver 

a.a.  anterior  adductor 

r.p.  posterior  retractor  pedis 

p.a.  posterior  adductor 

s.p.  eiphonal  papilla 

h.  heart 

1.  ligament 

x.  fold  of  the  mantle  above  the  hinge  teeth 

e.g.  /cerebral  ganglion 

p.g.  pedal  ganglion 

v.g.  visceral  ganglion 

K.  Kebei *'s  organ 

o.B.  organ  of  Bo j anus 

r.o.  reproductive  organs 

m.  mouth 

e.  esophagus 
s.  stomach 

i.  intestine 

t.  typhlosole 

r.  rectum 

a.  anus 

f.  foot 

i.r.g.  inner  right  gill 

m.  mantle 

c.  cut  edge  of  outer  left  gill 

mu.  transverse  muscles  of  visceral  mass 


PLATE  II 


d        s.  a 


PLATE  III 

Key  to  figure  5.     Internal  structures  shown  in  the  right  valve.    Left  valve  and 
left  fold  of  mantle  removed 
a.a.      anterior  adductor  muscle  in  section 
p.a.      posterior  adductor  muscle  in  section 
p.p.      protractor  pedis 
r.p.a.  anterior  retractor  pedis 
r.p.p.  posterior  retractor  pedis 
s.b.c.    superbranchial  chamber 
e.s.       exhalant  siphon 
i.s.        inhalant  siphon 
v.m.      visceral  mass 

f.  foot 

s.t.       siphonal  tentacle  or  papilla=nmbria 
1.  ligament 

b.  beak 

i.l.g.  inner  left  gill 

o.l.g.  outer  left  gill 

m.  mantle 

a.l.  anterior  lunule 
Key  to  figure  6.     Detail  of  vertical  section  of  a  labial  palp 

r.  ridge 

g.  groove _ 

e.  epithelium 

b.m.  basement  membrane 

c.t.  connective  tissue 

c.  cilia 

Key  to  figure   7.     Detail  of  vertical  section  of  ventral  furrow  at  junction  of 

labial  palps 

v.f.       ventral  furrow 

l.f .  lateral  furrows 
Key  to  figure  8.     Detail  of  epithelium  from  ventral  portion  of  dorsal  furrow  of 

labial  palps 

b.m.     basement  membrane 

g.  secreting  goblet  cell 

m.        mucous  cell 

c.  cilia 

w\  wandering  cell 

Key  to  figure  9.     Detail  of  fragment  of  pedal  ganglia 

n.         nerve  cells 

p.         parasitic  sporoeysts 


PLATE  III 


PLATE  IV 

Key  to  figure  10.     Vertical  section  through  labial  palps 

d.f .  dorsal  furrow 

c.t.  connective  tissue  with  cut  ends  of  small  bloodvessels 

e.  epithelium 

a.  labial  palp  artery 

r.  ridge 

g.  grooves 

v.f .  ventral  furrow 

].f.  lateral  furrow 


PLATE  IV 


i     op 


PLATE  V 

Key  to  figure  11.     Free-hand  transverse  section  through  edge  of  mantle 

o.e.      outer  epithelium 

c.t.      connective  tissue  layer 

m.       muscles 

i.e.      inner  epithelium 

i.f .      inner  fold 

s.p.     siphonal  papilla 

m.f.    middle  fold 

o.f.      outer  fold 

p.        periostracum 

c.        masses  of  calcareous  granules 
Key  to  figure  12.     Detail  of  inner  lobe  of  mantle — 10  micra  thick 

m.       mucous  material 
Key  to  figure  13.     Detail  of  groove  secreting  periostracum — 10  micra  thick 

p.       periostracum 

pi.      pigment  in  epithelium 

o.f.     outer  fold 

m.f.    middle  fold 
Key  to  figure  14.     Detail  of  layers  on  outer  side  of  mantle.     Oil  immersion 

e.        epithelium 

b.m.    basement  membrane 

m.       muscle  cells 

w.c.     wandering  cells 

c.t.      connective  tissue 

t.m.     transversely  cut  muscle  cells 


PLATE  V 


f.  m     ct       w  c 


u 


14 


PLATE  VI 

Key  to  figure  15.     Cross-section  through  folds  of  the  wall  of  the  glandular  por- 
tion of  the  organ  of  Bojanus 
1.  leucocyte 

e.         epithelium 
c.         connective  tissue 

Key  to  figure  16.     Epithelium  of  the  ventral  part  of  foot 

e.  epithelium 

s.  sub- epithelial  mucous  cells 

m.  muscles 

c.  connective  tissue 
Key  to  figure  17.     Cross-section  through  dorsal  portion  of  gills 

a.n.  arterial  net 

v.n.  venous  net 

c.  connecting  vessels  between  arterial  and  venous  nets 

w.t.  water  tube 

i.l.j.  interlamellar  junction 

la.  lamina  of  gill 

i.a.  interlamellar  artery 

os.  ostium 

f.  filament 

e.         ciliated  epithelium 
r.  supporting  rods 

m.        mucous  material 


PLATE  VI 


'my 


PLATE  VII 

Key  to  figure  18.     Cross-section  through  liver 

t.         tubules 

d.         duet 
Key  to  figure  19.     Detail  of  figure  IS 

t.         tubule 

d.  lumen  of  duct 

e.  ciliated  epithelium  of  duct 
g.         goblet  cell 

Key  to  figure  20.     Cross-section  of  rectum  in  region  of  the  heart 

t.  typhlosole 

c.  connective  tissue 

e.  ciliated  epithelium 

r.  lumen  of  rectum 
Key  to  figure  21.     Conventionalized  cross-section  through  visceral  mass 

n. c.  nerve  commissure 

o.B,  cut  ducts  of  glandular  portion  of  organ  of  Bo j anus 

i.  intestine 

t.  typhlosole 

r.o.  reproductive  organs 

t.m.  transverse  muscles  of  foot  and  visceral  mass 

m.  muscles  of  the  foot 

e.  folded  epithelium  and  subepithelial  mucous  cells 


PLATE  VII 


ECOLOGICAL  STUDIES  OF  THE  SHORT-NOSED 
GAR-PIKE  (LEPIDOSTEUS  PLATYSTOMUS) 

George  E.  Potter 

During  the  past  four  summers  a  study  has  been  made  upon  the 
short-nosed  gar-pike  in  the  Okoboji  Lakes,  Dickinson  County,  Iowa. 
The  work  was  carried  on  at  the  Lakeside  Laboratory  of  the  Gradu- 
ate College,  State  University  of  Iowa. 

There  is  a  group  of  seven  lakes  in  the  vicinity:  West  Okoboji, 
Spirit  Lake,  East  Okoboji,  Upper  Gar,  Middle  Gar,  Lower  Gar, 
and  Center  Lake.  West  Okoboji,  where  a  major  part  of  the  work 
was  done,  has  a  length  of  five  and  forty-six  one  hundredths  miles, 
a  width  of  two  and  eighty-four  one  hundredths  miles,  an  area  of 
three  thousand  seven  hundred  eighty-eight  acres,  a  mean  depth  of 
forty  feet  and  a  shore  line  of  eighteen  and  two  tenths  miles. 

In  these  waters  are  to  be  found  several  fresh  water  habitats. 
Some  of  these  are:-— (1)  the  deep  water  habitat  including  water 
from  twenty  to  one  hundred  and  thirty-two  feet  in  depth,  (2)  the 
pond-weed  or  water-plant  habitat,  found  in  water  from  five  to 
twenty  feet  in  depth  and  (3)  the  shoal  or  shore  habitat,  extending 
from  the  shore  out  to  where  the  water  plants  become  abundant, 
the  depth  varying  from  a  few  inches  to  four  or  five  feet.  It  is  in 
the  last  two  habitats  that  the  short-nosed  gar-pikes  are  most  abun- 
dantly found  in  the  summer,  because  it  is  here  that  they  find  their 
favorite  food  and  resting  place.  These  two  above  named  habitats 
are  particularly  extensive  in  Miller's  Bay  and  Emerson's  Bay  of 
West  Okoboji  and  in  upper  Gar  Lake.  These  areas  are  indicated 
by  an  X  on  the  accompanying  map  of  the  region. 

Observations  were  made  on  the  gar-pikes  by  floating  quietly  over 
the  water  in  a  row-boat  or  from  standing  on  the  shore.  Field 
glasses  were  used  to  good  advantage  in  either  case.  Specimens 
were  taken  for  the  purpose  of  examining  the  stomach  content  and 
studying  the  sexual  conditions  by  two  methods;  (a)  with  an  ordi- 
nary drag-net  or  seine  and  (b)  by  shooting  them  with  a  rifle.  Gar- 
pikes  have  a  habit  of  basking  at  the  surface  of  the  water,  in  which 
situation  a  hunter  may  slip  quite  close  in  a  boat,  and,  with  a  well 
aimed  shot,  kill  the  fish,  or  at  least  detain  it  until  it  can  be  taken 

17 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

into  the  boat  with  a  dip-net.    A  number  of  the  young  were  taken 
with  the  dip-net  from  the  shore. 

The  gar-pike  belongs  to  the  order  Holostei  and  it  has  been  sug- 
gested by  systematists  that  this  order  is  in  direct  line  between 
selachians  and  amphibians,  the  teleosts  branching  from  it.  The 
group  is  divided  into  several  families  all  of  which,  except  two,  are 
extinct.  The  Amiidae  are  represented  by  the  Bow-fin  (Arnia  calva) 
a  fish  with  fusiform  body,  thin  imbricated  cycloid  scales,  and  a 
cellular  air-bladder.  It  is^  abundant  in  the  waters  of  North  America. 
The  second  family  is  the  Lepidosteidse  (Gar-pikes)  with  an  elon- 
gate body,  both  of  the  jaws  greatly  elongated  to  form  a  beak.  The 
maxilla  is  divided  into  several  segments,  both  jaws  with  sharp  bony 
teeth,  the  tail  nearly  heterocercal,  air-bladder  cellular,  eyes  small, 
nostrils  near  the  anterior  end  of  the  beak,  scales  rhombic,  ganoid 
and  articulated.  There  is  one  living  genus  Lepidosteus,  whose 
representatives  inhabit  the  waters  of  North  and  Central  America. 
The  three  common  species  are ;  L.  platystomus  or  short-nosed  gar- 
pike  usually  smaller  and  having  a  somewhat  shorter  but  broader 
beak  than  the  following  species,  L.  osseus  or  common  long-nosed 
gar-pike,  which  has  a  very  long  beak  (six  or  seven  inches)  ;  these 
two  are  well  distributed  throughout  the  waters  of  the  middle 
United  States  while  the  third,  L.  tristcechus,  a  much  larger  fish 
(eight  to  ten  feet)  is  found  in  the  water  of  Central  America  and 
the  Southern  United  States. 

FEEDING  HABITS 

The  gar-pike  is  quite  carnivorous  in  its  food  habits,  a  fact  which 
has  considerable  bearing  upon  its  status  as  related  to  other  aquatic 
animals.  The  methods  used  in  ascertaining  the  food  habits  of  this 
fish  have  been,  (1)  to  capture  them  alive,  keep  them  in  captivity, 
and  feed  them,  noting  the  manner  of  taking  and  the  different 
kinds  of  food  that  will  be  accepted;  and  (2)  in  other  specimens 
dissect  the  stomachs  and  examine  the  contents  as  soon  as  fish  are 
collected.  The  food  of  this  form  proved  to  be  almost  entirely 
animal  matter.  Occasional  small  bits  of  plant  tissue  were  found 
in  the  stomachs  but,  since  the  amount  was  always  very  small  and 
such  occurrences  rare,  it  is  supposed  that  they  were  accidentally 
taken  with  other  food. 

The  writer  has  previously  published  tables1  of  data  on  the  food 


i  Iowa  Academy  of  Science,  Vol.  XXX,  1923. 


THE  SHORT-NOSED  GAR-PIKE  19 

of  this  animal,  so  the  discussion  here  will  be  of  a  more  general 
nature.  Other  fish,  such  as  perch  (Perca  flavescens),  bluegill 
sunfish  (Lepomis  pallidus),  common  sunfish  (Eupomotis  gibhosus), 
several  species  of  minnows  and  perhaps  others,  make  up  about  two 
thirds)  of  the  food  material  as  found  in  stomach  examinations.  The 
other  one  third  was  composed  of  crayfish  bodies.  In  a  number  of 
cases  there  were  parts  of  several  such  bodies  and  nothing  else. 

Stephen  A.  Forbes,  in  his  paper  "Food  relations  of  fresh  water 
fishes "  mentions  stomach  examinations  of  six  specimens  in  which 
he  found  only  the  bodies  of  other  fish  including,  hickory  shad, 
black  bass  and  minnows.  Forbes  and  Richardson  in  their  "Fishes 
of  Illinois"  state  that  young  gar-pikes  will  live  very  well  upon 
mosquito  larvas  alone.  Mr.  H.  E.  Richardson  reports  that  a  six- 
teen day  old  specimen  had  eaten  several  individuals  of  a  small 
crustacean,  ScapJwleberis  mucronata,  nothing  else.  In  another 
connection  he  says  that  the  adults  in  the  Illinois  river  have  been 
seen  swimming  near  the  surface  and  breaking  water  at  intervals 
to  seize  emerging  gnats  and  may-flies. 

During  the  warmer  weather  of  the  summer  months  the  gar-pike 
is  more  active  and  seems  to  do  most  of  its  feeding  in  the  morning 
hours,  spending  the  later  hours  of  the  day  basking  in  the  sun  at 
the  surface  of  the  water.  The  food  is  captured  by  grasping  it 
in  the  toothed  jaws.  In  case  the  food  is  another  fish  it  is  usually 
caught  with  the  length  of  the  body  across  the  gar-pike's  mouth, 
which  necessitates  manipulating  it  into  position  so  the  fish  can 
be  swallowed  head  foremost.  The  writer  has  kept  live  gar-pikes 
in  captivity  for  long  periods  of  time  feeding  them  every  four  or 
five  days  upon  dead  sunfish  or  perch  up  to  five  or  six  inches  in 
length  or  upon  beef  liver  cut  into  pieces  about  one  inch  square 
which  the  animals  swallowed  whole.  The  fish  have  some  difficulty 
in  getting  the  dead  objects  from  the  ground  to  the  mouth,  but 
after  a  trial  or  two  they  give  the  object  a  quick  push  with  their 
long  jaws  and  seize  it  while  it  is  up  in  the  water.  It  is  not  un- 
common for  a  gar-pike  two  feet  long  to  swallow  perch  that  are 
six  inches  in  length  or  sunfish  that  are  five  inches  long. 

The  food  habits,  it  is  seen,  are  not  confined  to  just  one  or  two 
species  of  other  animals,  but  include  several,  some  of  which  have 
quite  diverse- aquatic  habits.  The  gar-pike  then,  as  far  as  food 
habits  are  concerned,  has  not  greatly  limited  its  ecological  range 
in  the  fresh  waters. 


20 


IOWA  STUDIES  IN  NATURAL  HISTORY 


GROUND 

The  ground  or  lake  bottom  over  which  the  gars  are  found  varies 
a  great  deal.  Since  they  are  not  primarily  ground  feeders  it  does 
not  affect  them  greatly,  except  as  it  influences  the  habits  of  the 
animals  upon  which  they  prey.  The  perch,  sunfish  and  bass 
generally  occur  in  a  more  or  less  vegetated  area  of  mucky  or  sandy 
loam  bottom.  Their  food,  which  is  insect  larvae,  small  crustaceans, 
plants  and  some  small  fish,  is  found  here. 

The  gar-pike  itself  eats  crayfish  and  hence  it  is  often  seen  along 
sandy  or  gravelly  shores,  where  these  animals  abound.  The  ground 
seems  to  be  a  rather  indirect  factor  in  the  environment  of  this 
fish. 

ASSOCIATIONS 

All  living  animals  have  certain  relations  with  other  animals  and 
with  plants.  Naturally  the  animal  associates  of  the  gar-pike  are 
other  aquatic  animals,  with  somewhat  similar  habits.  Many  of 
these  are  made  use  of  as  food,  others  just  seem  to  happen  to  be 
together,  while  still  others  have  nearly  the  same  food  habits  as 
the  gar,  and  compete  more  or  less  with  it. 

These  associated  animals  are  so  divided  and  their  status  given 
in  the  following  tables. 


I.     Used  by  the  Gar-pike  as  Pood 


Yellow  perch 

Pumpkin-seed 

Bluegill 

Green  sunfish 

Minnows 

Black  bass2 

Hickory  shad2 

Crayfish 

Fly  larvae3 

Damsel  fly  larvae3 

German  carp 
Common  sucker 
Bullhead 
Leopard  Frog 
Bell's  turtle 
Snapping  turtle 


Perca  fiavescens 
Eupomotis  gibbosus 
Lepomis  pallidus 
Lepomis  cyanellus 
Cyprinidse 

Micropterus  salmoides 
Dorosoma  cepedianum 
Camharus  virilis 
Diptera 
Odonata 

II.     Accidental  Associates 
Cyprinus  carpio 
Catostomus  commersoni 
Ameiurus  nebulosus 
R<ma  pipiens 
Chrysemys  m.  belli 
Chelydra  serpentina 


Abundant- 
Abundant 
Abundant 
Rather  common 
Abundant 
Common 
Rare 
Abundant 


Abundant 

Rare 

Common 

Common 

Abundant 

Common 


2  Forbes  in  "Pood  Belations  of  Fresh  Water  Fishes.' > 

3  Pearse  in  f l  The  Food  of  the  Shore  Fishes  of  Certain  Wisconsin  Lakes. ' r 


THE  SHORT-NOSED  GAB-PIKE  21 

III.  Those  of  Similar  Food  Habits 

Black  bass  Micropterus  salnwides        Common 

Rock  bass  Anibloplites  rupestris          Rare 

Bullhead  Ameiurus  nebulosus            Common 

Wall-eyed  pike  Stizostedion  vitreum           Rare 

Common  pike  Esax  lucius                          Rare 

In  the  first  table  it  is  noticed  that  the  perch,  sunfish,  bluegill 
and  crayfish  are  abundant  in  the  regions  where  the  gar-pike  are 
found.  The  rule  is  quite  consistent,  that  if  a  gar  is  in  a  community 
at  least  some  of  the  others  mentioned  will  be  there  also.  The  group 
of  accidental  associates  may  be  brought  into  the  same  society  by 
their  food  habits,  for  protection,  or  to  reproduce.  All  of  these 
activities  may  be  somewhat  different  from  the  corresponding  habits 
of  the  gar-pike.  For  instance  the  carp  is  a  ground  feeder,  but 
in  an  area  where  there  are  water  plants,  there  is  much  food  for  it. 
Other  species  come  to  these  regions  because  the  plants  afford 
protection  for  both  adult  and  young.  There  is  a  number  of  other 
animals  whose  food  consists  of  the  same  material  as  that  of  the 
fish  listed.  The  search  for  their  favorite  food  therefore  brings 
them  into  association  with  the  gar-pike. 

PLANT  ASSOCIATIONS 

In  the  portion  of  the  lakes  where  the  gar-pikes  congregate  and 
are  nearly  always  to  be  found,  certain  water  plants  usually  occur. 
The  most  important  of  these  is  CeratopJiyllum  demersuni,  a  long 
slender-stemmed  plant,  often  many  feet  from  one  extremity  to  the 
other.  This  weed  grows  to  form  a  very  dense  mass,  much  of  which 
is  at  the  surface,  where  it  spreads  out  forming  an  even,  green  mat. 
Among  the  CeratopKyllurn  in!  the  shallower  water  is  often  found 
MyriopJiyllum,  a  somewhat  similar  plant.:  Still  another  plant  which 
occurs  in  the  habitat  of  the  gar,  is  Potamogeton  of  several  species. 
On  the  bottom  in  some  places  there  is  a  great  deal  of  Cham. 
Numerous  kinds  of  algse  are  found  throughout  the  water. 

The  dense  growth  of  plants  affords  food  and  protection  for  many 
fish,  small  crustaceans,  molluscs  and  larvae  of  insects.  Therefore 
they  will  be  attracted  here.  The  gars  come  here  in  search  of  these 
animals  for  food,  for  the  direct  protection  the  plants  offer,  and 
for  a  suitable  place  to  breed. 


22  IOWA  STUDIES  IN  NATURAL  HISTORY 

TOLERANCE  TO  ENVIRONMENTAL  CONDITIONS 

This  animal  is  able  to  tolerate  many  severe  conditions  which  are 
fatal  to  most  other  species  of  fish  in  a  very  short  time.  The  writer 
once  found  a  gar-pike  trapped  in  an  old  fish  cage.  Either  the 
animal  was  able  to  get  into  the  cage  at  a  time  when  the  water 
level  was  higher  (as  it  had  been  a  month  before)  and  was  unable 
to  get  out,  or  someone  had  placed  the  animal  there.  At  any  rate 
it  was  held  captive  and  the  water  had  lowered  until  most  of  its 
back  projected  out  of  the  small  amount  of  very  muddy  water  in 
the  puddle.  There  was  a  small  connection  of  water  between  that 
in  the  cage  and  the  main  lake.  The  oxygen  supply  of  the  little 
puddle  must  have  been  nearly  negligible  but  the  fish  was  able  to 
survive  without  much  apparent  discomfort. 

Following  this  incident,  some  experiments  were  made  in  view  of 
getting  a  definite  idea  of  the  fish's  tolerance  in  this  respect.  A 
live  gar-pike  was  placed  in  a  vessel  containing  five  gallons  of 
water  that  tested  8  cc,  of  oxygen  per  liter  (Winkler  method) .  The 
vessel  was  covered  with  screen,  but  with  some  space  between  the 
screen  and  the  water.  At  the  end  of  twenty-four  hours  the  water 
was  again  tested  for  oxygen  and  this  time  the  test  was  1.9  cc.  per 
liter.  The  fish  was  still  alive  and  apparently  not  suffering  in  the 
least.  At  the  end  of  twenty  days,  after  the  water  had  become 
extremely  foul,  the  fish  died.  The  water  was  tested  for  oxygen 
several  times  during  this  period  and  the  amount  present  always 
corresponded  very  closely  to  the  amount  found  at  the  end  of 
the  first  twenty-four  hours.  The  test  has  been  repeated  a  number 
of  times  and  the  results  coincide.  It  was  noticed  that  almost 
continually  during  the  experiment,  the  fish  would  come  to  the  sur- 
face at  intervals  of  several  minutes  and  gasp  in  air.  This  same 
action  has  been  noticed  by  the  writer  and  others  when  the  gar-pike 
is  in  natural  waters  where  the  oxygen  content  is  low.  Prom  this 
it  seems  quite  evident  that  the  gar-pike  has  other  means  of  res- 
piration besides  the  gills.  It  has  been  stated  by  others  that  this 
animal  uses  the  air-bladder  as  a  respiratory  organ,  but  the  writer, 
not  having  completed  experiments  to  determine  which  organ  does 
the  respiting  in  this  case,  is  not  ready  as  yet  to  make  a  statement. 
The  bullhead  (Ameiurus  nebulosus)  and  bow-fin  (Amia  calva)  are 
probably  its  closest  rivals  in  respect  to  tolerance  of  low  oxygen 
supply,  while  perch  and  sunfish  will  die  in  a  few  minutes  under 
the  same  conditions. 


THE  SHORT-NOSED  GAR-PIKE  23 

The  gar-pike  has  great  endurance  in  respect  to  rough  handling 
when  compared  to  many  other  fish,  such  as  the  perch,  sunfish,  bass, 
or  minnows,  many  of  which  will  succumb  from  simply  being 
dragged  ashore  in  a  net.  The  heavy  armor  of  scales  offers  very 
good  protection  from  injuries  by  physical  contact. 

This  ability  to  endure  severe  conditions  along  with  the  gar-pike's 
predaceous  habits,  strong  swimming  powers  and  its  natural  pro- 
tective coat  of  armor-like  ganoid  scales  have  probably  been  respon- 
sible for  its  long,  successful  existence.  These  factors,  no  doubt, 
also  have  a  bearing  upon  the  abundant  numbers  of  these  fish  to 
be  found  in  some  localities. 

ECONOMIC  IMPORTANCE 

The  gar-pike  is  a  branded  fish  and  has  a  wide-spread  reputation 
for  being  a  worthless  nuisance.  Since  it  is  predaceous  and  a 
voracious  feeder,  the  gar  is  very  destructive  to  other  fish.  In  Lake 
Okoboji  its  principle  food  is  perch  and  sunfish  and  it  is  reported 
that  black  bass  have  been  found  in  its  stomach.  These  fish  are 
all  used  as  food  and  game  by  man,  so  he  begrudges  the  gar-pike 
the  large  number  that  it  captures. 

The  fact  that  the  gar-pike  feeds  upon  crayfish,  minnows  and  a 
few  insect  larvae  is  a  second  charge  against  it.  Since  the  rock  bass, 
black  bass,  pickerel,  and  others  which  are  valuable  food  fish  make 
use  of  these  for  food,  the  large  amount  of  this  sort  of  food  con- 
sumed by  the  gar-pike  only  subtracts  from  the  supply  for  these. 
more  valuable  species.  Many  nets  and  other  fishing  tackle  are: 
destroyed  each  year  by  these  strong  fish.  It  is  reported  by  the  U.  S. 
Bureau  of  Fisheries  that  in  Carolina  the  nets  of  the  commercial 
shad  fisheries  often  become  loaded  with  gars,  nearly  to  the  exclusion 
of  the  marketable  fish.  At  the  same  time  the  nets  are  frequently 
torn  by  the  active  struggle  of  the  gars. 

The  fleshy  part  of  the  upper  sides  or  "loin"  of  this  fish  ha& 
been  used  for  food  by  Indians,  but  usually  white  people  have 
not  been  able  to  rid  it  of  the  strong  fishy  taste  and  odor.  However 
after  being  soaked  in  brine  over  night  and  well  baked  the  meat  is 
fairly  palatable.  It  is  reported  that  in  the  Mississippi  river  the 
gars  serve  as  host  for  glochidia  of  the  Yellow  Sand  Shell  Clam 
(Lampsilis  anodontoides) ,  an  important  button  producer.  Little 
else  can  be  said  in  favor  of  the  fish.  It  is  the  enemy  of  most  other 
fishes  at  some  stage  of  their  lives  and  with  its  strong  swimmings 


24  IOWA  STUDIES  IN  NATUKAL  HISTORY 

powers,  adaptability  and  other  natural  protection,  it  is  quite  safe 
from  other  aquatic  animals  and  conditions.  As  yet  no  satisfactory 
way  has  been  devised  for  clearing  our  waters  of  them,  if  that  is 
desirable.  However  it  has  become  customary  among1  fishermen 
upon  catching  them,  to  either  throw  them  out  on  the  shore  to  die 
or  to  break  their  heads  from  their  bodies. 

LIFE  HISTORY 

As  has  been  shown,  this  fish  has  a  rather  characteristic  life 
career.  It  is  endowed  with  means  for  leading  a  very  predaceous 
life,  and  with  ability  to  protect  itself  from  enemies,  as  well  as 
having  a  fairly  rapid  rate  of  reproduction,  so  it  is  able  to  perpetu- 
ate its  kind  quite  successfully.  The  seasonal  cycle  is  about  as 
follows.  During  the  summer,  June,  July,  and  August,  many  of 
these  animals  come  into  the  shallow  bays,  Little  Miller's  and  Little 
Emerson's  in  West  Okoboji,  where  they  feed  upon  smaller  fish 
and  spend  a  great  deal  of  time  basking  in  the  sun  on  warm  days. 
Then  about  the  end  of  August  they  begin  to  be  less  abundant  in 
these  shallow  bays,  making  their  way  to  the  deeper  water  for  the 
winter.  Fishermen  of  this  region  say  that  they  have  seen  gars 
through  holes  in  the  ice.  They  will  move  along  quite  near  the  ice, 
passing  across  the  open  hole,  apparently  not  afraid  of  a  man  who 
is  moving  about.  Their  movements  under  the  ice  seem  quite  aim- 
less. The  low  temperature,  slowing  up  the  metabolism,  is  more  than 
likely  responsible  for  this  semi-coma,  since  the  writer  has  kept 
live  specimens  through  the  winter  months  in  tanks  at  a  temperature 
of  seventy  degrees  F.,  with  no  such  results. 

The  time  of  spawning  is  quite  irregular  with  the  gar.  The 
weather  conditions  seem  to  cause  some  general  variations,  that  is, 
if  the  temperature  remains  low  until  late  in  the  spring,  the  general 
spawning  season  for  the  animal  will  be  a  little  later.  There  is  much 
variation  in  the  time  of  spawning  among  individuals,  some  spawn- 
ing as  late  as  July.  Several  were  seen  apparently  spawning  on 
May  twentieth,  in  the  south  end  of  Lower  Gar  Lake.  These  were 
the  first  to  be  observed  spawning  that  season  (1923). 

The  wTater  in  the  lower  end  of  Lower  Gar  Lake  is  quite  shallow, 
in  fact  that  part  of  the  lake  is  no  more  than  a  slough.  It  is  here, 
in  this  shallow  water  where  there  are  some  weeds  to  which  the  eggs 
may  attach,  that  the  spawning  occurs.  Sometimes  one  animal, 
supposed  to  be  a  female,  is  attended  by  two  or  more  others,  pre- 
sumed to  be  males,  but  occasionally  they  swim  in  pairs.     There  is 


THE  SHORT-NOSED  GAR-PIKE  25 

a  great  deal  of  rubbing  back  and  forth  along  the  sides  of  the 
female  as  they  all  move  repeatedly  over  the  same  ground.  Sud- 
denly the  female  slaps  her  tail  out  of  the  water  with  a  splash 
and  the  fish  are  gone  from  the  spot. 

The  eggs  are  deposited  in  small  masses,  held  together  by  a  clear 
gelatinous  substance,  which  attaches  to  the  weeds  or  even  to  the 
lake  bottom.  The  individual  eggs  are  about  the  size  of  buck-shot, 
or  3.5  mm.  in  diameter,  and  are  dirty-yellowish  in  color.  Their 
appearance  is  different,  perhaps,  from  that!  of  any  other  egg. 
Under  favorable  conditions  Mr.  R.  E.  Richardson  has  found  that 
the  eggs  will  hatch  in  eight  days.  The  young  fish  are  very  slender 
and  carry  a  yolk  sac  attached  to  their  ventral  side.  They  remain 
in  this  condition  about  seven  days  when  the  yolk  sac  is  entirely 
absorbed.  This  period  when  the  young  gar  is  carrying  the  large 
yolk  sac  is  the  most  helpless  part  of  its  whole  life.  As  soon  as  the 
sac  is  absorbed  the  fish  is  a  very  slender,  active  animal.  It  is  slaty 
gray  in  color  at  this  time  and  marked  with  a  broad  lateral  line  of 
black. 

During  this  time  the  principal  food  is  probably  Entomostraca 
and  mosquito  larvae.  But  very  soon  they  start  their  predaceous 
habit  of  preying  on  other  fish.  Forbes  and  Richardson  make 
mention  of  a  specimen  an  inch  and  a  quarter  long  which  had 
taken  a  minute  fish,  and  another1  two  inches  long  and  only  an  eighth 
of  an  inch  in  depth  had  filled  itself  with  no  less  than  sixteen  very 
young  minnows.  These  young  gars  stay  in  the  shallow  water,  and 
at  Okoboji  in  an  artificial  canal  among  the  water  plants,  until 
fall  when  they  go  to  deeper  water  with  the  adults.  About  fifteen 
of  the  fish,  varying  in  length  from  two  and  one  half  to  five  inches, 
were  taken  in  the  above  mentioned  canal  in  August  by  dipping 
them  up  in  a  net  from  the  shore.  The  fry  and  ftngerling  are  very 
seldom  seen  because  of  their  slender  build,  grayish  color,  shy 
habits  and  quick  actions.  Those  which  have  been  found  were 
solitary  near  the  shore,  usually  among  plants  and  over  a  muddy 
bottom.  In  this  way  the  young  animals  are  afforded  very  effective 
protection.  They  attain  a  length  of  four  to  six  inches  the  first 
summer,  so  as  a  rule  the  smallest  gars  seen  are  at  least  this  large. 
Their  growth  is  slightly  slower  the  second  season  and  the  animals 
become  bolder. 

The  specimens  seen,  which  where  supposed  to  be  spawning,  were 
all  at  least  fifteen  inches  or  more  in  length  which  is  larger  than 


26  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  second  year  animal,  so  it  is  likely  that  reproduction  does  not 
begin  until  after  the  second  year.  They  are  very  prolific,  the 
mature  ovaries  of  a  large  female  often  weighing  more  than  a 
pound.  Dr.  Evermann  reports  that  a  female  weighing  nine  pounds, 
contained,  by  actual  count,  36,460  eggs.  It  is,  then,  evident  that 
there  is  opportunity  for  rapid  increase  in;  their  numbers. 

BIBLIOGRAPHY 

Agassiz,  Alexander. 

1878.  Development  of  Lepidosteus.  Proceedings  of  American  Academy 
of  Arts  and  Science,  Vol.  14,  65-76. 

Evermann,  B.  W.,  and  Clark,  H.  W. 

1920.  Lake  Maxinkuckee.  Department  of  Fish  Conservation,  State  of 
Indiana,  Publication  7,  Vol.  1. 

Forbes,  S.  A. 

1878.  The  Food  of  Illinois  Fishes.  Bull.  Illinois  State  Laboratory  of 
Natural  History,  Vol.  1,  71-89. 

1878.  The  Food  of  Fishes.  Bull.  Illinois  State  Laboratory  of  Natural 
History,  Vol.  1,  18-65. 

1888.  Food  Relations  of  Fresh  Water  Fishes:  a  Summary  and  Dis- 
cussion. Bull.  Illinois  State  Laboratory  of  Natural  History,  Vol.  2, 
475-538. 

1888.  Studies  of  the  Fresh  Water  Fishes.  Bull.  Illinois  State  Labora- 
tory of  Natural  History,  Vol.  2,  433-473. 

1888.  Food  of  the  Fishes  of  the  Mississippi  Valley.  Trans.  American 
Fisheries  Society,  Vol.  17,  37-59. 

1909.  On  the  Distribution  of  the  Fishes  of  Illinois.  Bull.  Illinois 
State  Laboratory  of  Natural  History,  Vol.  8,  381-437. 

1914.    Fresh  Water  Fishes  and  Their  Ecology.    Illinois  State  Laboratory 

of  Natural  History.     Separate.    Urbana,  Illinois. 
Forbes,  S.  A.,  and  Richardson,  R.  E. 

1907.    Fishes  of  Illinois.     Bull.  Illinois  State  Laboratory  of  Natural 

History,  Vol.  3. 
Hankinson,  T.  L. 

1910.  Ecological  Notes  on  the  Fishes  of  Walnut  Lake,  Michigan.  Trans. 
American  Fisheries  Society,  Vol.  40. 

Harmier,  S.  F.,  Heidman,  W.  A.,  Bridge,  T.  W.,  and  Boulenger,  C.  A. 

1910.  Fishes,  Ascidians,  Etc.     The  Cambridge  Natural  History,  Vol.  3. 
Pearse,  A.  S. 

1916.  Food  of  the  Shore  Fishes  of  Certain  Wisconsin  Lakes.  Bull.  U. 
S.  Bureau  of  Fisheries,  Vol.  35,  245-292. 

1920.     Distribution  and  Food  of  Fishes  of  Green  Lake,  Wisconsin,  in 
Summer.     Bull.  U.  S.  Bureau  of  Fisheries,  Vol.  37,  253-272. 
Richardson,  R.  E. 

1911.  Observations  on  Breeding  Habits  of  Fishes  at  Havana,  Illinois. 
Bull.  Illinois  State  Laboratory  of  Natural  History,  Vol.  9,  405. 

Wilder,  B.  G. 

1877.  Gar-pikes,  Old  and  Young.  Popular  Science  Monthly,  Vol.  11, 
1-12. 


PLATE  I 


WATER  MITES  OF  THE  OKOBOJI  REGION 

Ruth  Marshall 

Rockf ord  College 

During  the  summer  of  1924  the  author  spent  some  weeks  at  the 
Lakeside  Laboratory  of  the  University  of  Iowa,  near  Milford,  in 
the  Okoboji  lake  region  of  the  northwestern  part  of  the  state. 
Through  the  courtesy  of  Dr.  Frank  A.  Stromsten,  Director  of  the 
Laboratory,  facilities  for  collecting  and  studying  the  water  mites 
were  provided;  the  author  wishes  to  acknowledge  here  the  assist- 
ance which  was  received  in  the  work.  This  paper  is  a  contribution 
to  the  work  of  the  Laboratory  in  securing  data  on  the  life  of  the 
lakes. 

The  Okoboji  region  is  especially  favorable  for  collecting  hydra- 
carina,  since  it  abounds  in  shallow  lakes,  ponds  and  sloughs  which 
support  an  abundant  aquatic  vegetation.  The  conditions  are  typ- 
ical of  a  recently  glaciated  region  of  the  upper  Mississippi  basin. 
Collections  were  made  in  July  and  August.  Most  of  the  material 
was  secured  from  West  Okoboji,  the  largest  of  the  lakes,  and 
especially  in  and  near  Miller's  Bay,  where  the  Laboratory  is 
located.  Other  lakes  visited  which  yielded  material  were  East 
Okoboji,  Upper  Gar,  Spirit,  Hottes,  Little  Spirit,  Center,  Robinson, 
and  Sunken  Lakes,  Milford  Creek  at  the  dam,  the  canals  and 
several  of  the  sloughs  in  the  region,  and  Loon  Lake  just  over  the 
Minnesota  boundary  line.  A  little  material  was  secured  in  Clear 
Lake  and  in  small  pools  near  Charles  City,  some  distance  east  of 
the  Okoboji  lakes.  No  mites  were  found  in  Welch,  Drummond, 
Middle  and  Lower  Gar  lakes,  nor  in  several  of  the  muddy  bordered 
sloughs  visited. 

In  addition  to  the  material  secured  by  the  author  by  the  use 
of  a  modified  Birge  collecting  net,  several  hundred  parasitic  mites 
of  the  genus  Unionicola  were  added  to  the  collection  through  the 
courtesy  of  Dr.  H.  M.  Kelly,  of  Cornell  College,  who  found  them 
in  the  course  of  his  investigations  on  the  trematode  parasites  of 
the  fresh  water  mussels  of  the  lakes. 

Altogether,  several  hundred  individuals  were  secured;  of  these, 
the  parasitic  Unionicolge  and  one  species  of  Fiona  {P.  reighardi), 

28 


WATEE  MITES  OF  OKOBOJI  29 

claimed  the  largest  number.  Fifteen  genera  were  represented  and 
thirty-seven  species  and  varieties,  of  which  eight  were  Arrhenuri. 
Five  of  the  species  appear  to  be  new  and  are  here  figured  and 
described.  In  this  connection  it  must  be  pointed  out  that  many 
of  the  ninety  or  more  recognized  genera  of  the  hydracarinse  have 
never  been  thoroughly  studied  in  this  country,  and  there  are  as 
yet  no  published  lists  of  the  North  American  species  of  many  of 
the  genera.  Consequently,  the  new  species  published  here  for  the 
first  time  are,  quite  probably,  not  rare  nor  peculiar  to  the  Okoboji 
region  but  only  now  recorded.  In  support  of  this  view,  it  may  be 
mentioned  that  no  new  species  were  found  for  the  genera  Arrhen- 
urus  and  Piona,  large  genera  which  have  been  studied  intensively. 
It  is  not  assumed,  of  course,  that  the  list  of  the  species  given  here 
is  at  all  complete. 

The  order  in  which  the  genera  are  arranged  is  one  of  convenience 
only;  the  larger  and  better  known  genera  are  given  first,  while 
the  representatives  of  the  "red  mites"  are  recorded  last. 

Genus  Arrhenurtjs 
The  Arrhenuri,  the  largest  genus  of  the  water  mites  are  always 
abundantly  represented  in  waters  like  those  of  the  Okoboji  group. 
They  were  found  in  all  the  lakes  except  Center.  Eight  species 
were  found,  with  more  than  one  hundred  and  sixty  individuals, 
besides  several  unidentified  females  and  nymphs.  Of  these  indi- 
viduals, over  half  belong  to  three  species  of  the  "long  tailed' ' 
forms  (Subgenus  Megaluracarus) ,  A.  marshalli  Pier.,  A.  manu- 
briator  Mar.,  and  A.  megalurus  Mar.  Arrhenurus  americanus  Mar. 
was  also  well  represented;  this  species,  with  A.  marshalli,  the  two 
American  species  of  the  genus  most  commonly  found,  claimed  also 
the  largest  numbers  here.  The  rarer  species  were  A.  laticaudatus 
Mar.  (four  individuals),  A.  lyriger  Mar.  (five),  both  found  in 
West  Okoboji;  A.  laticornis  Mar.  (two)  in  Upper  Gar,  and  A. 
frrifoliatus  Mar.  (one)  in  a  small  pool  at  the  State  Fish  Hatchery, 
near  Spirit  Lake. 

Genus  Piona 
This  genus  was  the  most  widely  distributed,  as  is  to  be  expected 
in  a  region  like  Okoboji ;  several  hundred  individuals  were  found, 
as  they  were  present  in  nearly  every  collection  made.  Five  species 
were  identified,  by  far  the  most  abundant  being  P.  reighardi 
(Wol.).     This  species,  perhaps  the  most  common  American  water 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

mite,  was  found,  both  sexes  and  nymphs,  to  the  number  of  several 
hundred.  They  were  especially  abundant  in  Loon  Lake,  Upper 
Gar  and  in  some  of  the  sloughs;  and  almost  the  entire  catch  from 
Robinson  Lake  consisted  of  mites  of  this  species.  Piona  pugilis 
(Wol.)  was  found  in  U^pper  Gar,  seven  individuals;  P.  inconstans 
(Wol.),  in  Miller's  Bay;  P.  spinulosa  (Wol.),  in  Spirit  Lake  and 
Clear  Lake;  P.  rotunda  (Kram.),  in  Upper  Gar.  The  last  three 
species  were  each  represented  by  one  individual  only. 

Genus  Limnesia 
Over  one  hundred  individuals  of  this  common  genus  were  found 
in  the  collecting  grounds.  Four  species  were  identified,  by  far 
the  largest  being  Limnesia  histrionica  (Herm.)  ;  this  common  and 
widely  distributed  species  was  especially  abundant  in  Upper  Gar 
and  Center  Lakes.  The  closely  related  form,  L.  wolcotti  Piers., 
a  variety  of  L.  histrionica,  was  likewise  found  in  several  places. 
Limnesia  americana  Piers,  was  found  (one  female)  in  Clear  Lake; 
and  L.  paucispina  Wol.  in  Miller's  Bay. 

Genus  Unionicola 

The  genus  is  represented  by  four  species,  three  being  parasites 
in  clams.  The  free  form  is  the  cosmopolitan  species,  Unionicola 
crassipes  (Mull.)  ;  this  was  found  only  in  Mailer's  Bay,  but  nearly 
fifty  individuals  were  secured,  most  of  them  in  the  deeper  water 
outside  of  the  bar. 

The  parasitic  species  were  found  by  Dr.  H.  M.  Kelly,  who  kindly 
made  the  identifications  of  the  fresh  water  mussels  in  which  they 
occurred.  Unionicola  abnormipes  (Wol.)  was  found  to  the  number 
of  several  hundred  in  the  examination  of  some  three  hundred  clams, 
Lampsilis  luteolus,  collected  in  West  Okoboji  and  Spirit  Lakes, 
at  several  stations.  Unionicola  ypsilophora  var.  haldermani 
(Piers.),  with  several  hundred  individuals  in  all,  was  found  in 
about  fifty  Anodonta  grandis  from  Spirit  Lake ;  and  U.  intermedia 
var.  wolcotti  (Piers.),  about  twenty-five  individuals,  was  found  in 
one  clam  (probably  Lampsilis  luteolus),  taken  in  the  Little  Sioux 
River  by  Mr.  Brenkleman.  The  infection  of  these  clams  by  the 
mites  was  almost  one  hundred  per  cent;  the  largest  number  found 
in  one  individual  was  one  hundred  and  eighty-six. 

Genus  Lebertia 
The  Okoboji  region  is  not  favorable  for  mites  of  this  large 
genus  which  are  more  abundant  in  deeper  and  cooler  waters.    But 


WATER  MITES  OF  OKOBOJI  31 

two  individuals  were  found;  these  proved  to  be  Lebertia  porosa 
Thor,  a  cosmopolitan  species.  They  were  collected  in  Miller's 
Bay,  outside  of  the  bar. 

Genus  Frontipoda 
One  individual  of  the  common  species,  Frontipoda  americana 
Mar.,  was  found  in  Loon  Lake,  Minnesota. 

Genus  Oxus 
Oxus  intermedins  new  species 
Plate  I,  figs.  1-3 
Three  mites  of  this  genus  were  found  in  a  brief  dredging  in 
the  border  of  Loon  Lake,  a  shallow  pond  near  Spirit  Lake.    They 
appear  to  belong  to  a  new  species. 

The  margins  of  the  epimeral  shield  come  barely  into  view  on  the  dorsal 
surface ;  the  posterior  border  has  a  deep  U-shaped  bay  in  which  lies  the  genital 
area.  The  genital  plates  do  not  project  beyond  the  bay,  however,  as  is  usual 
in  Oxus.  It  is  assumed,  because  of  the  deep  set  position  of  the  genital  plates, 
that  the  specimens  are  males.  These  plates  are  elongated  and  bear  several 
very  fine  hairs  each;  the  three  acetabula  usually  found  here  could  not  be  made 
out.  The  surface  of  the  epimeral  shield  is  closely  beset  with  very  fine  points; 
the  anterior  part  is  pinkish  in  color,  the  rest  of  it  greenish.  The  dorsal  side 
of  the  body  shows  dark  blotches.  The  palpi  are  rather  small;  the  legs  are 
greenish  blue,  the  fourth  ending  in  the  usual  long  saber-like  point  instead  of 
claws.  The  largest  of  the  three  individuals  found  measured  1.1  mm.  in  length 
and  0.6  mm.  in  the  widest  part ;  the  two  smaller  were  0.9  mm.  long  and  0.6  mm. 
wide.  In  the  latter,  presumably  somewhat  younger  individuals,  the  ventral 
shield  was  relatively  a  little  larger  than  in  the  largest  individual,  from  which 
the  drawings  were  made. 

Genus  Neumania 
PL  II,  figs.  10-12 

Six  species  of  the  genus  are  here  represented,  one  of  which  is 
new.  Neumania  tenuipalpis  Mar.  was  the  most  abundant,  being 
found  in  West  and  East  Okoboji,  Upper  Gar  and  Loon  Lakes  and 
at  the  dam  in  Milford  Creek.  Three  of  the  eighteen  individuals 
found  were  females.  As  this  sex  has  not  been  known  before,  a  figure 
of  the  genital  area  is  given  (fig.  10).  The  living  animals  of  both 
sexes  show  two  wedge-shaped  areas  on  the  dorsal  side  which  have 
very  dark  brown  dots  on  a  yellowish  background,  while  a  pale 
yellowish  blotch  lies  anterior  to  them.  The  eyes  are  red.  The  body 
is  covered  with  fine  lines. 

The  new  species,  to  which  the  name  N.  okobojica  has  been  given, 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

represented  by  one  female  individual  only,  was  found  in  Upper 
Gar  Lake. 

Neumania  okobojica  new  species 
It  is  a  large  mite,  1.45  mm.  long  and  1.2  mm.  wide,  oval,  dull  greenish  in 
color,  with  blue  plates  and  legs  and  a  heavy  integument.  The  epimera  are  of 
the  usual  form  and  size,  but  the  underlying  braces  from  the  first  pair  cannot 
be  made  out  in  a  surface  view.  The  palpi  are  very  small  but  stout.  The 
genital  area  of  the  female  is  close  to  the  epimera  and  is  very  distinctive,  since 
the  plates  of  either  side  bearing  the  acetabula  are  separated,  as  shown  in  the 
figure  (fig.  11). 

The  other  species  of  the  genus  which  were  found  were  N.  punc- 
tata Mar.  (at  the  Narrows  and  in  the  "Little  Canal")  >  three  males; 
N.  ovata  Mar.  (one,  "Little  Canal"),  N-  semicircularis  Mar.  (one 
each  in  Miller's  Bay  and  Emerson  Bay)  ;  A7,  brevibranchiata  Mar. 
(two  males,  in  Upper  Gar). 

Genus  Hygrobates 
The  genus  is  characteristically  a  northern  one ;  it  is  reported  as 
common  in  northern  Europe,  and  one  species  has  been  found  by 
the  author  in  large  numbers  in  Alaska.  But  one  individual  was 
found  in  the  Okoboji  collections;  this  was  a  newly  emerged  male 
found  in  Miller's  Bay  outside  of  the  bar.  It  appears  to  represent 
a  new  species,  not  hitherto  described  but  already  studied  by  the 
author. 

Hygrobates  ruber  new  species 
Plate  I,  figs.  5-7 
The  new  species  is  seen  to  resemble  E.  calliger  Piers,  differing  from  the 
European  form  in  several  details,  especially  in  the  genital  plates.  The  figure 
given  of  the  ventral  plates  of  a  mature  female  (fig.  5)  was  drawn  from 
material  collected  by  Professor  F.  C.  Baker  in  Lake  Winnebago,  Wisconsin, 
and  kindly  turned  over  to  the  author.  The  epimeral  plates  are  not  large ;  they 
lie  close  together  and  the  genital  area  is  not  far  removed  from  them.  The 
palpi  are  of  the  characteristic  size  and  shape,  with  a  well  developed  spiny 
peg  on  the  second  joint.  The  body  in  both  sexes  measures  about  0.9  mm.  The 
dorsal  side  of  the  body  is  brownish  with  a  red  streak  on  it;  this  latter  charac- 
ter has  suggested  the  specific  name,  H.  ruber. 

Genus  Koenikea 
This  genus  is  represented  here  by  the  fairly  common  species, 
Koenikea  concava  Wol.,  the  only  species  so  far  recorded  for  this 
continent.    Eight  individuals  were  found*  taken  from  Miller's  Bay, 
Upper  Gar,  the  Narrows  and  Center  Lake. 


WATER  MITES  OF  OKOBOJI  33 

Genus  Xystonatus 
Of  Xystonatus  asper  Wol.,  one  individual  was  found  in  each  of 
Upper  Hottes  and  Clear  Lakes.    It  is  the  only  species  of  the  genus 
recorded  for  North  America. 

Genus  Hydryphantes 
Adults  and  nymphs  to  the  number  of  eighteen,  found  in  four 
of  the  lakes  (Hottes,  Robinson,  Sunken  and  Spirit),  furnish  the 
material  for  the  formation  of  a  new  species  of  this  genus. 

Hydryphantes  tenuabilis  new  species 
Plate  II,  fig.  9;  Plate  III,  figs.  16-18 
The  dorsal  plate  bearing  the  median  eye  is  here  reduced  to  an  anterior  bar 
with  two  divergent  limbs,  the  posterior  divided  ends  of  which  are  somewhat 
variable  in  shape,  as  reported  also  in  other  species,  and  only  faintly  outlined. 
In  the  form  of  this  plate,  a  character  important  in  distinguishing  the  species 
of  the  genus,  the  new  species  resembles  H.  ramosus  described  by  Daday  from 
Paraguay.  The  body  is  ovate,  bright  deep  red  in  color,  and  the  largest  specimen 
is  1.05  mm.  long.  The  surface  is  thickly  beset  with  fine  rounded  elevations* 
The  ventral  plates  are  close  together,  a  little  farther  removed  in  younger 
individuals;  all  bear  short  bristles  or  hairs.  The  genital  area  is  large,  in  the 
center  of  the  body;  each  lateral  plate  bears  three  acetabula  of  about  equal 
size.  The  genital  plates  of  the  nymph  have  two  acetabula  each.  The  legs  are 
short,  and  the  last  three  bear  swimming  hairs. 

Genus  DlPLODONTUS 
One  species  of  this  large  genus  was  found ;  it  is  a  common  species, 
although  here  described  for  the  first  time,  and  given  a  name,  Z>. 
americanus.  In  the  Okoboji  region  it  was  found  in  Upper  Gar, 
at  the  Narrows,  and  in  Spirit,  Sunken  and  Loon  Lakes,  twenty- 
eight  individuals  being  secured.  Of  these,  several  were  nymphs, 
and  a  few  were  newly  emerged  adults,  all  taken  in  late  July  and 
early  August.  The  bodies  of  the  females  were  filled  with  large 
globular  eggs. 

Diplodontus  americanus  new  species 
PI.  I,  fig.  4;  PI.  II,  fig,  8;  PI.  Ill,  figs.  13-15 
The  body  is  almost  circular  in  outline,  orange  red,  with  a  large  dark 
scalloped  area  on  the  dorsal  side,  the  same  coloring  as  in  D.  despiciens  (Mull.), 
a  very  common  and  widely  distributed  species  in  the  Old  World  and  reported 
also  for  the  Americas.  Although  the  two  species  are  otherwise  very  similar, 
D.  americanus  has  a  different  form  of  genital  plates,  and  these  are  closer  in 
toward  the  last  epimera  and  also  broader  posteriorly.  In  these  particulars  it 
more  closely  resembles  D.  peregrirws  Koen.,  found  in  Brazil.     In  the  palps, 


34  IOWA  STUDIES  IN  NATUKAL  HISTOEY 

the  projection  of  the  fourth  joint  is  a  little  smaller  than  the  fifth  joint  with 
which  it  forms  the  claw.  The  epimeral  plates  are  typical  of  the  genus  and 
bear  many  hairs.  All  of  the  ventral  plates  are  close  together  in  the  very 
young  adults.  In  the  nymph,  the  genital  area  has  four  large  acetabula.  Newly 
emerged  individuals  measure  0.75  mm.  in  length;  old  adults  were  found  from 
1.3  to  1.75  mm.  In  other  collections  by  the  author  they  have  been  found  as 
large  as  two  millimeters. 

Genus  Eylais 
Only  one  individual  of  this  large  genus  of  the  "red  mites " 
was  secured.  This  was  found  at  the  dam,  Milford  Creek.  Its 
identification  is  uncertain ;  it  does  not  seem  to  conform  to  any  of 
the  few  species  of  the  genus  as  yet  described  for  North  America. 
Since  determination  of  the  species  depends  largely  on  details  of 
the  small  dorsal  eye  plate,  a  character  known  to  have  considerable 
range  of  variation,  it  does  not  seem  wise  to  record  a  species  from 
the  examination  of  only  one  specimen. 

Genus  Hydrachna 
It  is  surprising  to  find  that  this  large  and  common  genus  was 
not  represented  in  the  collections  from  the  Okoboji  waters.  One 
individual,  a  young  one,  was  found  in  Clear  Lake,  but  it  was  not 
identified.  Doubtless  more  systematic  collecting  at  other  stations 
would  have  yielded  more  material. 

Corrections 
In  the  paper,  "Water  mites  of  Alaska  and  the  Canadian  North- 
west' '  (Trans.  A.M.S.,  XLIII,  4,  1924),  two  regrettable  errors 
occur,  to  which  the  attention  of  the  author  has  been  called  in 
private  correspondence.  The  specific  name,  octoporus  (p.  238), 
being  preoccupied,  that  of  the  new  species  will  be  changed  to 
Hygrobates  neodctoporus.  The  new  species  longiseta  (p.  243) 
given  to  Piona  should  be  Neumania  longiseta. 

List  of  the  Species 

1.  Eylais  sp. 

2.  Hydryphantes  tenuabilis  new  species 

3.  Diplodontus  americanus  new  species 

4.  Hydrachna  sp. 

5.  Limnesia  Kistrionica  (Herm.) 

6.  Limnesia  Jiistrionica  var.  wolcotti  Piers. 

7.  Limnesia  americana  Piers. 

8.  Limnesia  paucispina  Wol. 


WATER  MITES  OF  OKOBOJI  35 

9.  Lebertia  porosa  Thor. 

10.  Frontipoda  americana  Mar. 

11.  Oxus  intermedins  new  species 

12.  Hygrobates  ruber  new  species 

13.  Unionicola  crassipes  (Mull.) 

14.  Unionicola  abnormipes  (Wol.) 

15.  Unionicola  ypsilophora  var.  haldermani  (Piers.) 

16.  Unionicola  intermedia  var.  wolcotti  (Piers.) 

17.  Neumania  tenuipalpis  Mar. 

18.  Neumania  punctata  Mar. 

19.  Neumania  ovata  Mar. 

20.  Neumania  semicircularis  Mar. 

21.  Neumania  brevibranchiata  Mar. 

22.  Neumania  okobojica  new  species 

23.  Koenikea  concava  Wol. 

24.  Fiona  reighardi  (Wol.) 

25.  Pionu  pugilis  (Wol.) 

26.  Fiona  inconstans  (Wol.) 

27.  Fiona  spinulosa  (Wol.) 

28.  Fiona  rotunda  (Kram.) 

29.  Xystonatus  asper  Wol. 

30.  Arrhenurus  marshalli  Piers. 

31.  Arrhenurus  megalurus  Mar. 

32.  Arrkenmrus  manubriator  Mar. 

33.  Arrhenurus  laticaudatus  Mar. 

34.  Arrhenurus  laticornis  Mar. 

35.  Arrhenurus  lyriger  Mar. 

36.  Arrhenurus  trifoliatus  Mar. 

37.  Arrhenurus  americanus  M!ar. 


PLATES 


PLATE  I 


Fig. 

1 

Fig. 

9 

Fig. 

O. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7 

Ox  us  intermedins,  dorsal   view 

0£-ms  intermedins,  lateral  view 

Oitr-M-5  intermedins,  ventral  view 

Diplodontus  americanus,  genital  area  of  the  nymph 

Hygrobates  ruber,  ventral  plates  ()f  i\ie   female 

Hygrobates  ruber,  genital  area  of  the  male 

Hygrobates  ruber,  right  palpus 


PLATE  I 


Joi-: 


PLATE  II 

Pig.     8.  Diplodontus  americanus,  the  two  eyes  of  the  left  side 

Pig.     9.  Hydryphantes  tenuabilis,  ventral  view 

Pig.  10.  Neumania  tenuipalpis,  genital  area  of  the  female 

Pig.  11.  Neumania  okobojica,  ventral  plates  of  the  female 

Pig.  12.  Neumania  okobojica,  palpus 


PLATE  II 


PLATE  III 

Fig.  13.  Diplodontus  americanus,  fourth  leg 

Fig.   14.  Diplodontus  americanus,  ventral  plates,  left  side 

Fig.  15.  Diplodontus  americanus,  capitulum  and  left  palpus 

Fig.  16.  Hy  dry  pliant  es  tenuabilis,  eye  plate 

Fig.  17.  Hydryphantes  tenuabilis,  palpus 

Fig.  18.  Hydryphantes  tenuabilis,  genital  area  of  the  nymph 


PLATE  III 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  10 


PAPERS  ON  IOWA  FUNGI 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY,  IOWA 


CONTENTS 


The  Iowa  Species  of  Russula  Grace  Winters 

Occurrence  of  Mycorrhiza  in  Iowa  Forest  Plants       M.  L.  Lohman 


THE  IOWA  SPECIES  OF  RUSSULA 

Grace  Winters 

INTRODUCTION 

The  name  Russula  was  first  used  by  Persoon  in  1796  to  designate 
a  section  of  the  genus  Agaricus.  In  his  Synopsis  of  1801  (5)  he  in- 
cludes twenty-four  species  in  the  section.  R.  emetica,  described  by 
Schaeffer  in  1774  as  Agaricus  emeticus,  is  usually  regarded  as  the 
type.  Among  European  botanists  Persoon,  Schaeffer,  Fries,  Quelet, 
and  Romell  have  studied  the  genus  extensively.  In  America  most  of 
the  work  on  Russula  has  been  contributed  by  Peck,  Kauffman,  (3) 
Beardslee,  (1)  and  Burlingham  (2). 

Practically  no  work  has  been  done  on  the  local  occurrence  of  the 
genus  in  Iowa,  and  in  view  of  this  fact  a  taxonomic  study  of  Rus- 
sulas  was  begun  in  the  summer  of  1924.  The  work  has  been  carried 
on  in  the  mycological  laboratory  of  the  State  University  of  Iowa, 
under  the  direction  of  Professor  G.  W.  Martin.  The  mycological 
herbarium  contains  thirty-nine  determined  species  of  Russula  col- 
lected within  the  state.  The  only  previous  mention  of  Russulas  in 
Iowa  seems  to  be  the  three  reported  by  Shimek  (6)  from  the  Lake 
Okoboji  region.  The  thirty-nine  species  at  Iowa  City  include  speci- 
mens from  Johnson,  Dubuque,  and  Clayton  counties,  which  were 
gathered  over  a  period  of  three  years  from  1923  to  1926. 

In  this  state,  Russulas  form  a  conspicuous  part  of  the  mycological 
undergrowth  in  open  oak  woods.  Usually  they  make  their  appear- 
ance in  the  middle  of  the  summer  and  last  through  early  fall. 

The  present  study  is  only  a  beginning,  as  much  work  remains  to 
be  done  on  this  genus.  It  is  hoped  that  in  the  future  collections  can 
be  secured  from  various  parts  of  the  state  which  will  permit  a  more 
comprehensive  knowledge  of  the  Russulas  of  Iowa.  In  compiling 
the  descriptions  of  species  constant  reference  has  been  made  to  the 
works  of  Beardslee,  Burlingham,  and  Kauffman,  especially  the  last- 
named.    The  order  of  species  is,  in  general,  that  of  Kauffman. 

TECHNIQUE 

For  collecting  Russulas  no  elaborate  equipment  is  necessary;  a 
large  market-basket  and  plenty  of  newspaper  are  all  that  is  needed. 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

A  heavy  knife  or  narrow  trowel  is  handy  to  loosen  the  soil  around 
the  base  of  the  stipe,  for  while  no  volva  is  present,  the  complete  stipe 
should  always  be  secured. 

Each  individual  collection  can  readily  be  kept  separate  by  wrap- 
ping in  newspaper  and  packing  loosely  in  a  basket.  This  procedure 
is  important,  since  many  of  the  species  are  much  alike  and 
without  a  great  deal  of  experience  it  is  difficult  to  distinguish  be- 
tween them.  The  spores  are  not  as  liable  to  become  mixed  when 
each  collection  is  kept  separate,  and  any  spore-prints  deposited  on  a 
wrapper  will  be  with  the  specimens  that  produced  them. 

In  the  study  of  Russulas  it  is  essential  to  secure  a  good  spore- 
print.  Only  mature  pilei  should  be  used.  Cut  the  stipe  near  the 
pileus  and  place  the  pileus  with  gills  down  on  a  white  paper.  Cover 
with  a  beaker  or  bell- jar  and  leave  for  several  hours.  Black  paper 
may  be  used  where  the  gills  look  white.  With  mature  specimens  a 
mass  of  spores  will  be  deposited  whose  color  is  distinct.  Often  small 
worms  or  insects  are  bothersome.  If  so,  a  few  crystals  of  paradi- 
chlorbenzene  under  the  bell- jar  will  kill  the  pests  without  injuring 
the  specimens. 

The  value  of  adequate  collection  data  can  not  be  over-stressed. 
They  should  include  date,  locality,  habitat,  color  of  spore-print,  taste, 
odor,  and  name  of  collector.  These  data  can  be  effectively  listed  on 
the  slip  on  which  the  spore-print  is  deposited.  As  the  specimen  is 
unwrapped,  in  preparation  for  the  work  in  the  laboratory,  a  small 
piece  of  the  pileus  may  be  tasted.  It  is  not  at  all  difficult  to  distin- 
guish between  the  mild  and  acrid  forms,  as  the  difference  is  quite 
pronounced. 

The  taste  is  an  extremely  important  taxonomic  character  and  must 
be  obtained  when  the  specimen  is  fresh.  There  are  several  forms  in 
the  Russula  collection  at  Iowa  City  where  the  spore-print  is  lacking 
and  the  taste  not  recorded,  hence  it  has  been  impossible  to  identify 
them  with  certainty. 

A  record  of  the  locality  in  which  collections  are  made  is  important, 
especially  when  one  is  working  over  a  given  area  such  as  a  state. 
Material  may  be  abundant  in  one  part  of  the  area  and  scanty  in  an- 
other. Some  species  of  Russula  are  found  only  in  open  oak  woods, 
others  among  conifers.  In  this  state  Russulas  have  been  collected 
only  in  open  oak  woods.  A  description  or  mention  of  habitat  often 
aids  in  identification. 

The  summer  of  1924  was  hot  and  rainy,  an  ideal  season  for  fungi. 


IOWA  SPECIES  OF  RUSSULA  7 

Russulas  are  summer  and  early  fall  forms,  August  being  ordinarily 
the  best  month  for  their  collection.  Though  the  latter  part  of  the 
summer  of  1925  was  dry,  the  early  fall  was  rainy,  which  resulted  in 
an  excellent  production  of  Russulas  in  many  forms.  Abundant  col- 
lections were  made  until  the  middle  of  October,  which  is  rather  un- 
usual for  this  region. 

Drying  of  the  specimens  is  simple.  When  the  sun  is  bright  enough 
and  the  atmosphere  not  too  humid,  air  drying  is  effective.  If  this 
method  can  not  be  used,  the  specimens  may  be  dried  in  a  slightly 
heated  oven.  In  the  laboratory  at  Iowa  City  the  specimens  are 
placed  on  a  wire  net  over  a  radiator  and  dried.  In  this  process  the 
heat  kills  the  parasites.  After  the  specimens  are  thoroughly  dry, 
they  are  ready  to  be  put  in  the  herbarium,  the  spore-print  and  col- 
lection data  being  filed  with  each  specimen.  It  is  well  to  add  a  small 
amount  of  naphthalene  to  guard  against  further  attack  by  insects. 

In  identification,  work,  microscopic  cross-sections  of  the  gills  are 
often  of  service.  A  small  piece  of  pileus  with  gills  attached  may  be 
placed  between  pieces  of  pith  and  sectioned  with  a  razor.  These 
sections  must  be  sufficiently  thin  for  the  study  of  the  structure  of 
the  hymenium  and  trama.  Dried  specimens  lend  themselves  very 
nicely  to  sectioning.  A  small  portion  of  the  pileus  may  be  soaked  in 
water  for  a  short  time,  then  sectioned  in  the  same  manner  as  the 
fresh  material.  When  the  section  is  placed  on  the  slide  a  drop  of  7 
per  cent  potassium  hydroxide  may  be  added.  This  causes  the  cells 
to  distend,  giving  them  a  more  natural  appearance.  An  ordinary 
compound  microscope  with  low  and  high  power  objectives  may  be 
employed  to  examine  the  slide.  The  low  power  gives  the  general 
contour  of  the  section,  while  the  higher  power  serves  to  show  the  de- 
tails of  the  hymenium.  An  oil  immersion  objective  is  not  necessary 
in  the  study  of  cross-sections,  but  is  very  helpful  in  studying  the 
spores.  It  is  often  necessary  to  resort  to  the  use  of  microscopic  sec- 
tions when  identifying  closely  related  species. 

DISCUSSION  OF  THE  GENUS 
The  genus  Russula  may  be  characterized  as  follows:  Trama 
vesiculose,  without  milky  juice ;  pileus  fleshy,  continuous  with  stipe, 
variable  in  color,  with  or  without  separable  pellicle,  dry  or  viscid ; 
margin  even  or  striate ;  gills  attached,  rigid  but  fragile ;  stem  cen- 
tral, rigid ;  veil  absent,  spores  white,  creamy,  or  yellow ;  taste  acrid 
or  mild ;  odor  none  or  characteristic  in  a  few  species  only. 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

Russala  is  a  very  distinct  genus,  most  closely  related  to  Lactarius, 
from  which  it  differs  by  its  lack  of  a  milky  juice.  Hygraphorus  dif- 
fers in  the  thicker  and  more  waxy  nature  of  the  gills,  although  there 
are  evident  signs  of  relationship  between  this  genus  and  certain 
species  of  Ritssula. 

The  most  distinctive  feature  of  the  genus  is  the  character  of  the 
trama,  which  with  that  of  the  Lactarii  is  most  unique  among  the 
Agarieaceae.  Hyphse  of  the  usual  slender,  filamentous  type,  as 
found  in  the  other  genera,  are  rather  scanty  and  interweave  among 
clusters  of  thin-walled,  parenchyma-like,  isodiametrie  cells,  forming 
the  so-called  vesiculose  trama;  this  accounts  for  the  more  or  less 
brittle  consistency  of  the  pileus. 

The  hymenium  and  subhymenium  are,  in  some  species,  quite  char- 
acteristic. Cystidia  may  or  may  not  be  present ;  if  present,  they  may 
be  few,  scattered,  abundant,  short,  blunt,  clavate  or  long  and  point- 
ed. This  character  is  found  to  be  constant  for  each  species.  The 
subhymenium  may  be  distinct  or  may  merge  gradually  into  the  tis- 
sue of  the  trama. 

While  the  trama  is  the  most  outstanding  generic  character,  spore- 
prints  and  spores  are  the  most  essential  means  of  settling  the  identi- 
ty of  closely  related  species.  The  color  of  the  spore-print  is  constant 
for  each  species,  but  may  fade  with  age,  hence  all  herbarium  spore- 
prints  should  be  accompanied  by  careful  notes  of  the  print  when 
fresh.  The  color  varies  from  a  pure  chalk-white  to  a  rather  pro- 
nounced ochre  and  is  one  of  the  most  valuable  diagnostic  characters. 

By  staining  the  spores  with  MielzerV  reagent  and  using  an  oil 
immersion  objective,  the  spore-markings  may  be  determined.  This 
reagent  stains  the  markings  on  the  spore  wall  without  staining  the 
wall  itself.  If  this  reagent  is  not  used,  the  markings  may  be  made 
out  only  by  means  of  an  oil  immersion  objective  and  even  then  with 
difficulty  and  uncertainty. 

The  spores  may  be  divided  into  two  groups,  according  to  the  mark- 
ings ;  the  reticulate  and  echinulate  types.  The  echinulate  group  is 
further  subdivided  into  those  with  long  spines  and  those  with  blunt 
spines;  the  reticulate  group  also  consists  of  two  types,  those  with 
crests  or  ridges  and  those  with  fine  connections.    When  the  diagnos- 


iMelzer's  reagent  (4) 

Potassium  Iodide  1.5  grams 

Iodine  .5  grams 

Water  20.0  grams 

Add  to  this  solution  an  equal  amount  of  chloral  hydrate. 


IOWA  SPECIES  OF  EUSSULA  9 

tic  characters  are  almost  identical,  the  spore  markings  may  be  the 
determining  factor.  In  fact,  in  closely  related  species,  the  presence 
or  absence  of  cystidia  and  the  spore  markings  are  the  only  differ- 
entiating factors. 

The  pileus  may  be  convex,  plane,  or  depressed  in  the  center,  and 
exhibits  a  great  variety  of  colors :  red,  purple,  yellow,  green,  and 
white.  The  specimens  of  the  same  collection  may  vary  in  color,  ac- 
cording to  light  exposure  or  age. 

A  differentiated  pellicle  composed  of  more  or  less  specialized 
hyphae  is  present  on  the  surface  of  the  pileus.  It  may  become  viscid 
in  wet  weather,  or  may  remain  dry  and  become  pruinose  or  velvety. 
The  pellicle  is  somewhat  separable  along  the  margin  and  in  some 
species  may  be  easily  peeled  from  nearly  the  whole  surface. 

The  flesh  of  the  pileus,  when  fresh,  is  white  or  whitish,  or  it  may 
be  tinged  grayish  or  purplish.  In  many  of  the  red  forms,  the  flesh 
under  the  pellicle  is  tinged  red  or  reddish ;  on  exposure  to  the  air, 
after  bruising  or  in  age,  it  may  turn  ochraceous  or  blackish. 

The  margin  may  be  even  or  striate,  or  even  at  first,  becoming 
striate  in  age.  In  species  with  thin  pilei,  the  lines  of  attachment  of 
the  gills  to  the  pileus  show  through  as  raised  ridges  and  these  stri- 
ations  may  extend  toward  the  center  of  the  pileus.  In  the  species 
with  firm  thick  pilei  the  striations  are  not  as  clearly  marked  or  are 
obscurely  developed  on  the  margin.  They  may  appear  when  the 
plant  becomes  old.  This  character  is  somewhat  variable  and  must 
be  used  with  caution. 

The  gills  are  brittle,  thin,  with  acute  edges,  simple  or  forked,  of 
equal  or  unequal  length.  The  colors  for  the  different  species  are  of 
all  shades  between  white  and  deep  ochre-yellow.  This  fact  alone 
separates  them  from  any  spore-color  groups  of  the  Agaricaceae.  The 
gills  may  become  darker  with  age  or  may  stain  where  bruised.  The 
shape  and  width  are  constant  and  are  of  value  in  identification. 

The  stem  is  central  or  nearly  so;  solid,  firm,  spongy  or  stuffed, 
becoming  hollow,  but  never  fibrous,  usually  white,  sometimes  red  or 
slightly  ochraceous,  in  some  species  changing  to  ashy  or  brownish 
where  bruised. 

The  taste  is  sharply  acrid  in  some  species,  slowly  or  slightly  acrid 
in  others,  and  entirely  mild  in  a  considerable  number.  This  is  an 
important  character  for  the  identification  of  the  species  and  is  fair- 
ly constant.  In  all  species  it  is  necessary  to  have  fresh  specimens  in 
order  to  determine  whether  or  not  acridity  is  present.    Almost  all 


10  IOWA  STUDIES  IN  NATUKAL  HISTORY 

the  species  are  edible  after  careful  cooking,  since  even  the  peppery 
forms  then  lose  their  sharp  taste ;  in  any  case  the  mild  species  are 
said  to  be  perfectly  safe  when  fresh,  young,  and  clean. 

The  odor  of  some  species  is  quite  characteristic  and  should  always 
be  considered.  One  must  not  confuse  this  test  by  applying  it  to 
plants  already  in  the  first  stages  of  decay. 

KEY  TO  THE  IOWA  SPECIES  OF  RUSSULA 

Pileus  some  shade  of  red  or  purple „ 1 

Pileus  not  some  shade  of  red  or  purple. 27 

1-  Spores  pure  white  in  mass — not  creamy  white ~^... 2 

1—  Spores  not  white  in  mass  including  creamy  white _ 10 

2-  Taste   promptly   acrid ~ . - 3 

2—  Taste  mild  or  tardily  acrid _ - 6 

3-  Flesh  white  under  pellicle - 4 

3-  Flesh  red  under  pellicle — ..  5 

4-  Gills   thin,    crowded,   moderately   broad ;    margin   striate ;    very   fragile 

_ „ _ .B.  fragilis 

4-  Gills  subdistant,  attached  by  a  point;  edge  even 22.  fallax 

5—  Pileus  rosy  to  blood  red,  color  even;  pellicle  separable;  margin  strongly 

tuberculate  striate - —22.  emetica 

5—  Pileus  darker,  often  purplish;  pellicle  adnate,  scarcely  separable;  often 

yellow  spotted;  margin  slightly  striatulate  in  age ....22.  atropurpurea 

6-  Edge  of  gills  flocculose-crenulate ;  blood-red;  viscid,  when  dry  as  if  with 

bloom;  striate  only  when  fully  expanded—. — B.  pwrpwina 

6—  Not  as  above _ —  7 

7—  Pileus  purplish  or  deep  rose  pink,  later  variegated  with  olive  or  green- 

ish; flesh  grayish,  under  pellicle;  often  tardily  acrid Z2.  variata 

7-  Not    as    above .....  8 

8—  Pileus  rigid,  unpolished;  margin  obtuse;  not  striate;  sometimes  slightly 

bitterish  or  subacrid _ B.  lepida 

8-  Pileus  thin ;   fragile 9 

9-  Pileus  2-5  cm.  broad;  pink  or  bright  flesh,  unicolorous... - B.  uncialis 

9-  Pileus  5-14  cm.  broad;  bright  rosy  red,  shading  into  yellowish  blotches 

J2.  subdep aliens 

10-  Taste  acrid 11 

10-  Taste  mild  15 

11-  Taste  tardily  but  truly  acrid 12 

11-  Taste   promptly   acrid * 14 

12-  Pileus  6-12  cm.  broad;  uniform  red  or  spotted;  gills  crowded,  narrow, 

fragile,  white  to  yellow  ochraceous B.  tenmoeps 

12-  Not  as  above „ 13 

13—  Pileus  rosy  red ;  3-6  cm.  broad ;  spores  and  gills  creamy  white~22.  sangmnea 

13—  Pileus  Corinthian  red,  fading;  up  to  9  cm.  broad;  spores  ochraceous  in 

mass ;  gills  yellowish B.  corinthiwubra 

14-  Pileus  2-5  cm.  broad;  pale  dull  red  to  rosy  red;  soon  dry;  stem  white 

or  rosy  tinged B.  subpunctata 

14-  Pileus  5-7  cm.  broad;   deep  rosy  red;   viscid  when  moist;   stem  white, 

never  red. — _ 22.   veternosa 

15-  Flesh    white,    unchanging 16 

15-  Flesh  changing  with  age  or  where  wounded,  or  tinged  under  pellicle.-..*— 22 

16—  Pileus  salmon  or  salmon  tinged  to  dull  red  in  center;  margin  drooping; 

spores  maize  yellow 22.  hwnidicola 

16-  Pileus  without  salmon  color  or  tinge;  spores  not  maize  yellow .17 

17-  Pileus  2.5-8   em.  broad;  red  to  paler,  yellowish  on  disk;  margin  even, 

slightly  striate  when  old;  stem  white  to  yellowish  at  base.... 22.  luteobasis 


IOWA  SPECIES  OF  RUSSULA  11 

1 7-  Not  as  above *. 18 

18-  Pileus  2-5  cm.  broad ;  some  shade  of  red  or  purple,  fading  to  yellowish  on 

disk;  stem  2-5  cm.  long,  4-6  mm.  thick,  slender,  white... .B.  chamceleontina 

18-  Not  as  above- 19 

19-  Pileus  2.5-5  cm.  broad;  rosy  red  to  flesh  red  fading  to  yellowish  on  disk, 

stem  white  or  rose  tinged,  2.5-5  cm.  long,  5-12  mm.  thick,  tapering 
upwards  ~ JR.  roseipes 

19-  Not  as  above — 20 

20-  Pileus  rosy-flesh  to  peach  color;  fragile;  gills  white  at  first  to  bright 

ochraceous  yellow -JR.  amygdaloides 

20-  Not   as   above. . 21 

21-  Pileus  8-12  cm.  broad;  dull  colors,  reddish  purple,  sordid  red,  reddish 

predominating;  gills  ochraceous  becoming  darker  with  age.~.JR.  alutacea 

21-  Pileus  5-10  cm.  broad;  color  from  buff  to  reddish-brown  to  dark  dull 

red,  fading;  gills  white  to  cream  or  buff JB.  integra 

22-  Flesh  staining  slowly  red  then  black  where  wounded JB.  rubescens 

22-  Not  staining  slowly  red  then  black  where  wounded 23 

23-  Flesh  red  under  cuticle;  firm;  blood  red JR.  borealis 

23-  Flesh  not  red « 24 

24-  Odor  disagreeable  in  age;  pileus  purplish  red,  olivaceous,  variegated; 

stem  changing  to  ochraceous  brown  where  handled B.  xerampelina 

24-  Odor  none ;  pileus  not  variegated  with  olive  tints. . 25 

25-  Purple  or  dark  purplish  red;  cuticle  adnate;  gills  yellowish  to  bright 

ochraceous  buff. _ _ B.  ochrophylla 

25-  Not  as  above _ _ 26 

26-  Pileus  4-7  cm.  broad ;  rather  pliant ;  dark  dull  red,  sometimes  blackish  on 

disk;  stem  becoming  ashy  or  blackish _ B.  obscura 

26—  Pileus  5-12  cm.  broad;  firm;  orange-red  to  ochre  on  disk,  darker  red  on 

margin;   stem  becoming  cinereous -. E.  decolorans 

27—  Spores  white  in  mass,  not  creamy  white -. 28 

27-  Spores  not  white  in  mass,  including  creamy  white * 39 

28-  Pileus  white  - „ 29 

28-  Pileus  not  white 31 

29-  Pileus  8-15  cm.  broad;  gills  short  and  long  alternating;  mild  to  weakly 

acrid  _ B.  delica 

29-  Pileus  2.5-5  cm.  broad;  gills  not  short  and  long  alternating;  acrid 30 

30-  Margin   even — * _ B.   albidula 

30-  Margin  striate B.  fragilis 

31—  Flesh  white,  unchanging,  not  tinged  under  cuticle «. 32 

31-  Flesh  white,  changing  or  tinged  under  cuticle - 37 

32—  Stem  stained  at  base  by  cinnabar  red  stains J2.  fcetentula 

32—  Base  not  stained  at  base  by  cinnabar  red  stains * 33 

33-  Taste  tardily  and  slightly  bitterish ~. L 34 

33-  Taste  mild  35 

34-  Pileus  6-12  cm.  broad;  soon  dry;  stem  4-5  cm.  long B.  ochraleucoides 

34-  Pileus  3-6  cm.  broad;  viscid;  stem  3-4  cm.  long _ M.  raoultii 

35—  Pileus  5-10  cm.  broad;  pale  grayish  green  paler  or  sub-ochraceous  in  cen- 

ter; margin  even;  spores  white  tinged  yellow B.  viridella 

35-  Not  as  above- ^ 36 

36-  Margin  striate  when  mature;    cystidia  present;    pileus  with  crust-like 

areas;  viscid  when  young  or  moist JB.  orustosa 

36—  Margin  not  striate;  no  cystidia;  pileus  with  floecose  pulverulent  areas; 

dry  _..J2.   virescens 

37—  Pileus  whitish,   clouded  with  umber;   flesh  changing  to  reddish  where 

bruised  then  blackish _ _ R.  nigricans 

37-  Not  as  above ~ „ _ _ 38 

38-  Pileus  3-7  cm.  broad;  straw  color  to  brown;  striate B.  pectinatoides 

38—  Pileus  5-12  cm.  broad;  variegated;  not  striate B.  variata 

39-  Flesh  white,  not  changing,  tinged  under  pellicle 40 

39-  Flesh  changing  with  age  or  tinged  under  pellicle. .41 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

40-  Pileus  purple-brown  on  disk;   margin  dull  garnet;  mild  to   somewhat 

nauseous - B.   nauseosa 

40-  Not  as  above , 42 

41-  Pileus  buff  to  reddish  brown  to  dull  red;  spore-print  cream  yellow  to 

pale    ochraceous JR.    integra 

41-  Pileus  umber-yellow  to  golden  yellow ;  spore-print  maize  yellow..^,  flaviceps 

42—  Flesh  thick  on  disk,  thin  elsewhere;   grayish  or  grayish  purple  under 
pellicle;  odor  unpleasant  when  fresh +. _...jB.  xerampelina 

42—  Flesh  not  grayish  nor  grayish  purple  under  pellicle _ 43 

43—  Pileus  3-7  cm.  broad;  from  dingy  straw  color  through  to  umber  brown; 

margin   striate M.   pectinatoides 

43-  Pileus  5-8  cm.  broad;  dull  yellow;  even  or  slightly  striate  in  age B.  flava 

DESCRIPTION  OF  SPECIES 
1.     Russula  delica  Fr. 

Pileus  8-15  cm.  broad,  firm,  convex — umbilicate  then  depressed  to 
infundibuliform,  dull  white,  sometimes  with,  rusty-brown  stains,  un- 
polished, glabrous,  pubescent  or  obscurely  tomentose,  even,  dry, 
margin  at  first  involute,  not  striate. 

Flesh  compact,  white  or  whitish,  not  changing  where  bruised. 

Gills  subdecurrent,  narrowed  behind,  broader  in  middle,  distant 
or  subdistant,  thickish,  short  and  long  alternating,  few  forked,  white 
or  whitish,  edge  often  distinctly  greenish. 

Stem  2-5  cm.  long,  1.5-2  cm.  thick,  short,  stout,  solid,  equal  or  sub- 
equal  or  tapering  down,  white  becoming  dingy,  not  turning  blackish 
when  bruised,  glabrous  or  subtomentose  above,  often  with  a  narrow 
pale-green  zone  at  apex. 

Taste  mild  to  tardily  but  weakly  acrid. 

Odor  none. 

Spores  globose,  9-10  microns,  tuberculate,  white  in  mass.  This 
species  is  reported  by  Shimek  from  the  Okoboji  region.  I  have  not 
collected  it. 

2.     Russula  nigricans  Fr. 

Pileus  7-15  cm.  broad,  subrigid,  convex  then  depressed  to  sub- 
infundibulif orm ;  margin  at  first  incurved  then  spreading  and  ele- 
vated, often  irregularly  wavy,  at  first  whitish  and  clouded  with 
umber,  soon  smoky -umber,  subviscid  at  first,  glabrous,  even  on  mar- 
gin. 

Flesh,  compact,  white,  changing  to  reddish  where  bruised,  then 
blackish. 

Gills  narrowed  or  rounded  behind,  adnexed,  thick  and  firm,  sub- 
distant  to  distant,  short  and  long  alternating,  white  becoming  gray- 
ish, reddish  at  first  when  bruised. 


IOWA  SPECIES  OP  EUSSULA  13 

Stem  2-6  cm.  long,  1-3  cm.  thick,  solid,  hard,  stout,  white  at  first, 
at  length  smoky-umber,  reddish  then  blackish  where  bruised. 
Taste  mild,  sometimes  tardily  but  slightly  acrid. 
Odor  none. 

Spores  subglobose,  8-10  microns,  reticulate,  white  in  mass. 
Cystidia  short  and  blunt. 

3.  Russula  virescens  Fr. 

Pileus  5-12  cm.  broad,  at  first  globose,  soon  convex  and  expanded, 
often  somewhat  depressed,  firm,  dry  or  velvety,  surface  of  disk 
broken  into  many  floccose  or  pulverulent  areas  or  patches,  green  or 
grayish  green,  the  margin  not  striate  or  rarely  so,  cuticle  scarcely 
distinguishable  or  separable. 

Flesh  white. 

Grills  white,  rather  close,  narrowed  towards  stem,  almost  or  en- 
tirely free,  few  shorter  and  forked. 

Stem  3-7  cm.  long,  1-2  cm.  thick,  white,  firm,  equal  or  subequal, 
solid  or  spongy. 

Spores  subglobose,  6-8  microns,  echinulate,  with  few  very  fine 
reticulations,  spines  scattered  and  blunt,  white  in  mass. 

Cystidia  none,  no  differentiated  subhymenium. 

4.  Russxda  crustosa  Pk. 

Pileus  5-12  cm.  broad,  firm,  convex  then  expanded  and  depressed 
in  the  center,  surface  cracked  except  on  disk,  the  areas  crustlike, 
sordid  cream-color,  dirty  brownish  or  ochraceous,  usually  tinged 
with  olive  or  green,  viscid  when  young  or  moist,  especially  on  the 
disk,  striate  on  margin  when  mature. 

Flesh  white. 

Gills  dull  white,  dingy  cream  color  in  age,  rather  broad  in  front, 
narrowed  toward  stem,  adnexed  or  free,  thick,  distinct,  not  crowded, 
rather  brittle,  few  forked,  few  short. 

Stem  3-6  cm.  long,  1-2.5  cm.  thick,  short,  stout,  spongy-stuffed, 
subequal,  ventricose  or  white. 

Taste  mild. 

Odor  none. 

Spores  broadly  ovate,  7-8  x  8-10  microns,  reticulate,  white  in 
mass. 

Cystidia  rather  numerous  extending  through  subhymenium. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

5.     Russula  viridella  Pk. 

Pileus  subglobose  or  very  convex,  becoming  nearly  plane  or  cen- 
trally depressed,  5-10  cm.  broad,  surface  pale  grayish-green,  paler 
or  subochraceous  in  the  center,  dry,  soon  minutely  squamulose  or 
furfuraceous,  except  in  the  center,  margin  even. 

Flesh  white. 

Gills  white,  few  short  ones  present,  some  forked,  thin,  narrow, 
close. 

Stem  white,  equal  or  nearly  so,  even,  solid  or  spongy  within,  5-7.5 
cm.  long,  1-1.6  cm.  thick. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  7-8  microns  in  diameter,  reticulations  very  fine, 
white  tinged  with  yellow  in  mass. 

Cystidia  subfusiform  80  x  16  microns. 

6.     Russula  ochraleucoides  Kauff. 

Pileus  6-12  cm.  broad,  large,  rigid,  convex,  soon  expanded-plane, 
varying  strata  yellow  to  pale  ochraceous,  usually  dull  ochre  to  red- 
dish ochre  toward  center,  pellicle  adnate,  soon  dry,  pulverulent  or 
subrimose,  even  on  the  obtuse  margin. 

Flesh,  thick,  compact,  white,  unchanging  or  slightly  sordid  in  age. 

Gills  adnexed  or  free,  rather  narrow,  rounded  or  slightly  broader 
in  front,  wliite  or  whitish,  close  to  subdistant,  shorter  ones  inter- 
mingled, often  forked  in  posterior  part,  intervenose. 

Stem  4-6  cm.  long,  1.5-2  em.  thick,  short,  rigid,  equal  or  tapering 
slightly  downward,  white,  glabrous  or  subpruinose,  spongy-solid, 
even  or  obscurely  wrinkled. 

Taste  tardily  and  slightly  bitterish,  acrid  or  disagreeably  bitter. 

Odor  faintly  aromatic  or  none. 

Spores  globose,  7-9  microns,  reticulate,  white  in  mass. 

Cystidia  few  to  moderately  abundant. 

7.     Russula  raoultii  Quel. 

Pileus  broadly  convex,  then  plane  or  slightly  depressed  in  center ; 
3-6  cm.  broad,  surface  straw-yellow  or  massicot  yellow,  viscid,  gla- 
brous, margin  even  or  at  length  very  faintly  striate. 

Flesh  pure  white,  unchanging. 

Gills  white,  some  short  ones  intermingled,  rarely  forking  next  to 
the  stipe,  interspaces  slightly  venose,  narrow,  2-6  mm.  broad,  acute 
at  the  inner  ends,  close. 


IOWA  SPECIES  OF  RUSSULA  15 

Stem  white,  not  changing  color,  somewhat  pruinose,  tapering 
downward,  stuffed,  3-4  cm.  long,  1-2  cm.  thick. 
Taste  tardily  peppery. 
Odor  none. 

Spores  globose,  6-9  microns  in  diameter,  reticulate,  white  in  mass. 
Cystidia  rather  abundant. 

8.    Russula  lepida  Fr. 

Pileus  4-10  cm.  broad,  rigid,  convex,  then  expanded-depressed, 
cuticle  adnate,  and  disappearing  on  disk,  unpolished,  soon  dry,  rose- 
red  to  pale  blood-red,  fading,  disk  soon  pallid  or  variegated  with 
paler  yellowish-reddish  hues,  sometimes  rimulose-cracked  or  rugulose 
on  disk,  margin  obtuse,  not  striate. 

Flesh  compact,  white  or  reddish  under  the  cuticle,  thick,  abrupt- 
ly thin  on  margin. 

Gills  narrowed  behind  and  narrowly  adnate  or  almost  free,  close, 
rather  narrow,  broader  and  rounded  in  front,  white  then  whitish, 
few  shorter,  occasionally  forked. 

Stem  4-7  cm.  long,  1-2  cm.  thick,  equal  or  slightly  tapering  down- 
ward, white  or  tinged  rosy-pink,  spongy-stuffed,  rather  rigid,  ob- 
scurely wrinkled. 

Taste  mild,  sometimes  slightly  bitterish,  subacrid. 

Odor  none  or  very  slightly  disagreeable. 

Spores  subglobose,  7-8  x  9-10  microns,  reticulate,  white  in  mass. 

Cystidia  moderately  abundant,  subcylindrical,  70-75  x  10-12 
microns. 

9.    Russula  fwtentula  Pk. 

Pileus  3-7  cm.  broad,  soon  fragile,  at  first  subhemispherical  then 
convex  to  plane  and  depressed,  viscid,  livid-ochraceous,  russet- 
tinged,  disk  darker  and  innately  granular,  long  tuberculate-striate, 
margin  at  first  incurved. 

Flesh  thin,  whitish. 

Gills  adnexed  or  nearly  free,  close,  rather  narrow,  broader  in 
front,  thin,  whitish,  often  spotted  or  stained  reddish. 

Stem  2.5-5  cm.  long,  6-12  mm.  thick,  subequal,  somewhat  firm, 
spongy-stuffed,  soon  cavernous,  whitish  or  sordid-white,  stained  at 
base  by  cinnabar-red  stains. 

Taste  very  slightly  acrid. 

Odor  none  or  somewhat  like  oil  of  bitter  almonds,  varying  in  in- 
tensity. 


16  IOWA  STUDIES  IN  NATUKAL  HISTOKY 

Spores  6-7  x  7-9  microns,  eehinulate,  creamy-white  in  mass. 
Cystidia  moderately  abundant. 

10.     Russula  pectinatoides  Pk. 

Pileus  3-7  cm.  broad,  rather  firm,  becoming  fragile,  thin,  convex, 
then  piano-depressed,  viscid  when  moist,  covered  by  a  thin  separa- 
ble pellicle,  radiately  rugose-striate  on  the  margin,  often  half  way 
to  the  center,  or  strongly  tub  ercidar -striate,  dingy  straw  color, 
brownish,  yellowish-brown  or  umber-brown. 

Flesh  white,  thin,  becoming  fragile,  slightly  ashy  under  the  cuti- 
cle, not  changing. 

Gills  whitish,  close  to  subdistant,  thin,  distinct,  equal,  moderately 
broad,  broadest  in  front,  narrowed  behind,  often  stained  or  broken 
half  way  from  stem,  some  forked  at  base. 

Stem  2-5  cm.  long,  5-1  cm.  thick,  white  or  dingy,  subequal  gla- 
brous, spongy-stuffed,  then  hollow,  even. 

Taste  mild  or  slightly  and  tardily  acrid. 

Odor  not  noticeable. 

Spores  subglobose,  6-8  microns,  eehinulate,  white  in  mass. 

Cystidia  few. 

11.    Russula  subpunctata  Kauff. 

Pileus  2-5  cm.  broad,  rigid,  convex  then  expanded-plane  to  de- 
pressed, cuticle  adnate  and  scarcely  separable  on  margin,  subviscid, 
soon  dry,  pale  dull  red  to  rosy  red,  often  white-spotted  where  cuticle 
disappears,  minutely  rivulose  or  subgranular,  margin  even,  acute. 

Flesh  compact,  firm,  rather  thick  on  disk,  abruptly  thin  on  margin. 

Gills  adnate  to  subdecurrent,  thin,  slightly  alternate  at  both  ends, 
not  broad,  close  to  subdistant,  whitish,  then  pale,  cream-color xd, 
few  short  or  forked  at  base,  pruinose,  intervenose. 

Stem  2-4  cm.  long,  4-10  mm.  thick,  subequal  or  tapering  down, 
spongy-stuffed,  becoming  cavernous,  white  or  rosy-tinged,  unchang- 
ing, attached  at  times  to  roots  and  forming  mycorrhiza. 

Taste  quickly  and  very  acrid. 

Odor  none. 

Spores  subglobose,  7-9  x  9-11  microns,  reticulate,  creamy  white  in 
mass. 

Cystidia  abundant,  subcylindrical,  90-110  x  8-12  microns. 

12.     Russula  variata  Banning  and  Pk. 
Pileus  5-12  cm.  broad,  fleshy,  firm,  convex  then  depressed  to  sub- 
infundibuliform,  viscid,  not  striate,  purplish  or  deep  rose  pink  when 


IOWA  SPECIES  OF  RUSSULA  17 

young,  later  variegated  with  olive  or  dark  umber,  or  sometimes 
greenish  with  only  a  trace  of  purple,  opaque  and  reticulate-wrinkled 
under  lens,  the  thin  pellicle  slightly  separable  on  the  thin  margin, 
with  a  subsilky  or  dull  lustre  when  dry. 

Flesh  white,  firm,  cheesy,  tinged  grayish  under  pellicle. 

Gills  shining  and  persistently  white,  adnate-decurrent,  thin, 
rather  crowded,  narrowed  at  both  ends,  not  broad,  subdichotomously 
forked,  interspaces  venose. 

Stem  4-7  cm.  long,  1-3  cm.  thick,  white,  firm,  solid,  equal  or  sub- 
equal,  sometimes  tapering  downward,  even. 

Taste  mild  to  tardily  acrid  or  slightly  astringent. 

Odor  none. 

Spores  subglobose,  6-7  x  9-10  microns,  echinulate  with  very  fine 
reticulations,  white  in  mass. 

Cystidia  few  and  short. 

13.    Russula  atropurpurea  Maire 

Pileus  5-14  cm.  broad,  rigid,  medium  to  large  size,  convex  then 
plane,  soon  depressed,  rather  firm,  viscid,  pellicle  adnate  and  scarce- 
ly separable  on  the  margin  only,  scarlet  to  dark  crimson  when  fresh 
and  young,  becoming  darker  to  purplish  when  mature  or  on  dying, 
pruinose,  disk  often)  darker,  sometimes  blackish,  red  to  livid  oliva- 
ceous purple,  sometimes  yellow  spotted ;  margin  even  or  only  slight- 
ly striatulate  in  age. 

Flesh  dark  red  under  the  pellicle,  white  elsewhere,  not  changing 
to  ashy. 

Gills  white,  dingy  in  age,  rather  narrow,  close  behind,  subdistant 
in  front,  adnexed,  few  short,  interspaces  venose. 

Stem  4-7  cm.  long,  1-3  cm.  thick,  subequal,  medium  stout,  white 
with  a  dull  lustre,  pruinose,  even,  spongy-stuffed,  apex  floccose- 
punctate. 

Taste  acrid. 

Odor  none. 

Spores  oval,  8-10  microns,  reticulate,  white  in  mass. 

Cystidia  numerous. 

This  is  the  form  described  under  this  name  by  Kauffman.  R. 
atropurpurea  as  used  by  Burlingham  and  others  seems  to  be  quite 
distinct.    See  note  under  R.  xerampelina. 

14.     Russula  xerampelina  Fr. 
Pileus  5-10  cm.  broad,  firm,  convex  then  piano-depressed,  dry  or 
very  slightly  viscid  in  wet  weather ;  pellicle  hardly  separable ;  not 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

striate  on  margin ;  surface  glabrous  or  subpruinose,  purplish-red  to 
purplish-olive,  disk  olivaceous  variegated. 

Flesh  compact,  whitish  then  dingy. 

Gills  creamy,  creamy -white  to  creamy -yellowish,  then  sordid, 
rather  close,  adnexed,  moderately  broad  throughout,  thickish,  often 
forked,  shorter  ones  usually  intermingled,  interspaces  venose. 

Stem  white  or  rosy-tinged,  soon  dingy  olivaceous-yellowish  where 
handled,  5-7  cm.  long,  1.5-2.5  cm.  thick,  firm,  subventricose  or  equal, 
spongy-stuffed,  even  or  obscurely  wrinkled,  changing  where  bruised 
to  dirty  ochraceoas-brown. 

Taste  mild. 

Odor  disagreeable  with  age  or  when  dying. 

Spores  subglobose,  7-8  x  9-10  microns,  echinulate  with  a  few  reti- 
culations, creamy-yellowish  in  mass. 

Cystidia  present,  not  extending  much  beyond  basidia. 

I  include  in  this  species  forms  that  grade  into  R.  squalida  Pk. 
and  R.  atropurpurea  Pk.  since  I  fail  to  find  in  our  specimens  any 
sharp  distinctions  which  seem  to  justify  separation. 

15.    Russula  ochrophylla  Pk. 

Pileus  fleshy,  firm,  convex,  becoming  nearly  plane  or  slightly  de- 
pressed in  the  center,  5-10  cm.  broad,  surface  purple  or  dark-pur- 
plish-red, dry,  cuticle  not  easily  separable,  unpolished,  glabrous, 
margin  even,  rarely  very  slightly  striate  when  old. 

Flesh  white,  purplish  under  the  adnate  cuticle. 

Gills  yellowish  at  first,  becoming  bright  ochraceous-buff  when  ma- 
ture, pruinose,  equal,  few  forked  at  the  stipe,  venose-connected,  sub- 
distant,  adnate. 

Stem  reddish  or  rose-tinted,  paler  than  the  pileus,  white  in  one 
variety,  solid,  spongy  within,  equal  or  nearly  so,  3.5-6.5  cm.  long, 
1-2  cm.  thick. 

Taste  mild,  edible. 

Odor  none. 

Spores  globose,  10  microns,  echinulate  with  a  few  reticulations, 
bright  ochraceous  in  mass. 

Cystidia  moderately  abundant,  rather  short. 

16.     Russala  decolorans  Fr. 
Pileus  5-12  cm.  broad,  often  large,  firm,  globose  at  first  then  con- 
vex and  piano-depressed,  orange-red  usually  ochre  on  disk  and  dark 


IOWA  SPECIES  OP  RUSSULA  19 

red  on  margin,  pellicle  separable,  snbviscid,  margin  even,  slightly 
striate  in  age. 

Flesh  white,  becoming  cinereous  with  age,  or  where  broken,  be- 
coming fragile. 

G-ills  pale  yellowish-ochraceous  at  maturity,  white  at  first,  thin, 
fragile,  moderately  broad,  close,  adnexed,  forked  at  base,  few  short. 

Stem  5-12  cm.  long,  1-2.5  cm.  thick,  stout,  long  spongy  or  solid, 
wrinkled-rivulose,  white,  the  flesh  becoming  cinereous  with  age  or 
where  bruised. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  7-9  microns,  reticulate,  pale  ochraceous-yellow 
in  mass. 

Cystidia  very  numerous. 

17.    Russula  flava  Romell 

Pileus  5-8  cm.  broad,  rather  fragile,  convex,  then  piano-depressed, 
even  or  slightly  striate  in  age,  dry  in  dry  weather,  somewhat  viscid 
when  moist,  pellicle  separable,  dull  yellow,  color  hardly  fading,  but 
sometimes  ashy,  discolored  in  age. 

Flesh  white  becoming  cinereous  with  age. 

Gills  white  at  first,  becoming  yellowish,  broadest  towards  front, 
narrowly  adnate,  close,  distinct,  becoming  slowly  gray  in  age. 

Stem  chalk-white  at  first,  the  flesh  becoming  ashy,  equal  or  sub- 
equal,  spongy-stuffed,  obscurely  reticulate-rivulose,  rather  fragile, 
6-8  cm.  long,  1-2  cm.  thick. 

Taste  mild. 

Odor  none. 

Spores  globose,  8-9  microns,  echinulate  with  a  few  reticulations, 
yellowish  in  mass. 

Cystidia  present,  rather  short. 

18.    Russula  obscura  Romell 

Pileus  4-7  cm.  broad,  rather  pliant,  convex  then  piano-depressed, 
dull,  dark  blood-red,  pileus  sometimes  blackish  on  disk,  thin,  the 
pellicle  continuous  and  separable,  hardly  viscid  when  moist,  sub- 
pruinose  when  dry,  even  or  slightly  striate  in  age. 

Flesh  whitish,  becoming  ashy. 

Gills  white  at  first,  then  dingy  straw-color,  moderately  broad, 
narrowly  adnate,  close,  mostly  forked  at  base,  equal,  interspaces 
sometimes  venose. 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

Stem  white,  becoming  ashy  or  blackish,  rarely  tinged  red,  sub- 
equal,  4-6  cm.  long,  10-15  mm.  thick,  spongy-stuffed,  rigid,  soon  soft, 
obscurely  wrinkled. 

Taste  mild. 

Odor  none. 

Spores  subglobose  to  ovate,  7-8  x  8-10  microns,  echinulate,  pale 
ochraceous  in  mass. 

Cystidia  rather  numerous,  subulate. 

19.     Russula  rubescens  Beards. 

Pileus  4-10  cm.  broad,  firm,  becoming  fragile,  convex-plane,  dull 
red,  variegated  with  yellowish,  ochraceous  or  olivaceous-purplish 
hues,  at  first  darker,  fading,  pellicle  adnate,  dry,  scarcely  separable 
and  substriate  on  the  margin,  subglabrous,  margin  acute  at  first. 

Flesh  whitish,  staining  slowly  red  then  black  where  wounded,  be- 
coming cinereous  with  age. 

Gills  narrowly  adnate,  broader  in  front,  close  to  subdistant,  me- 
dium broad,  equal,  rarely  forked,  white  at  first  then  pale  creamy- 
ochraceous,  intervenose. 

Stem  3-7  cm.  long,  1-2.5  cm.  thick,  subequal  or  tapering  down, 
spongy-stuffed,  glabrous,  even,  white,  becoming  cinereous  in  age, 
changing  slowly  to  red  then  blackish  where  bruised. 

Taste  mild. 

Odor  none. 

Spores  globose,  7-10  microns,  echinulate,  pale  ochraceous  in  mass. 

Cystidia  few  and  short,  subhymenium  not  differentiated. 

This  species  is  very  abundant  in  the  vicinity  of  Iowa  City. 

20.     Russula  borealis  Kauff. 

Pileus  5-9  cm.  broad,  firm  and  rather  compact,  convex  then  piano- 
depressed,  outline  broadly  elliptical,  often  with  a  sinus  on  one  side, 
blood-red,  disk  darker  or  color  uniform  and  not  fading,  pellicle 
somewhat  separable,  hardly  viscid,  margin  even  or  obscurely  striate. 

Flesh  white,  red  under  the  cuticle,  not  very  thick. 

Gills  ochraceous,  subdistant  or  moderately  close,  medium,  broad, 
broader  in  front,  narrowly  adnate,  rather  distinct,  edge  often  red- 
dish anteriorly,  equal,  a  few  forked  toward  base,  interspaces  venose. 

Stem  mostly  white,  tinged  red  in  places;  firm,  spongy-stuffed, 
thickened  below,  5-7  cm.  long,  1.5-2  cm.  thick. 

Taste  mild,  sometimes  slightly  and  tardily  acrid. 

Odor  none. 


IOWA  SPECIES  OF  EUSSULA  21 

Spores  subglobose,  7  x  9.5  microns,  echinulate  with  few  reticula- 
tions, deep  ochraceous-yellow  in  mass. 
Cystidia  few  and  pointed. 

21.    Russula  alutacea  Fr. 

Pileus  8-15  cm.  broad,  large,  firm,  convex  then  depressed,  with 
dull  colors,  dark  reddish-purple,  sordid  red,  sometimes  mixed  with 
other  shades,  the  reddish  color  predominating,  with  somewhat  separ- 
able pellicle,  glabrous,  somewhat  viscid  in  wet  weather,  soon  dry, 
pruinose  and  subgranulose,  margin  even  or  somewhat  short-striate 
in  age. 

Flesh  white  thick. 

Gills  ochraceous  from  the  beginning,  deeper  ochraceous  to  tan- 
colored  when  mature,  rather  broad,  thick,  subdistant,  broader  in 
front,  rounded  adnexed,  of  equal  length. 

Stem  7-10  cm.  long,  3-4  cm.  thick,  very  firm,  stout,  solid,  tinged 
red  or  entirely  white,  subequal  or  ventricose,  almost  even. 

Taste  mild. 

Odor  none  or  pleasant. 

Spores  subglobose,  9-11  microns,  echinulate,  ochraceous-yellow  to 
alutaceous  in  mass. 

Cystidia  present. 

22.  Russula  nauseosa  Fr. 

Pileus  broadly  convex,  becoming  plane  to  depressed,  up  to  5  cm. 
broad,  surface  purple-brown  at  the  center,  shading  to  garnet-brown 
or  dull  garnet  toward  the  margin,  sometimes  becoming  pale,  viscid 
when  wet,  with  the  pellicle  separable,  glabrous,  margin  becoming 
tuberculate-striate  or  furrowed. 

Flesh  white,  fragile. 

Gills  light  yellow,  then  dingy  ochraceous,  with  a  few  shorter  ones 
intermingled  here  and  there,  adnexed,  ventricose,  somewhat  distant. 

Stem  white,  up  to  2.5  cm.  long,  and  about  .8  cm.  thick. 

Taste  mild,  but  somewhat  nauseous. 

Odor  disagreeable  with  age. 

Spores  8-9  microns  in  diameter,  echinulate,  yellow  in  mass. 

Cystidia  present. 

23.  Russida  emetica  Fr. 

Pileus  5-10  cm.  broad,  fleshy,  soon  fragile,  convex  to  piano-de- 
pressed, rosy  to  blood-red,  sometimes  faded  to  white,  pellicle  separ- 


22  IOWA  STUDIES  IN  NATURAL  HISTORY 

able,  margin  strongly  tuber  cular-striate  or  even  sulcate,  viscid  and 
shining. 

Flesh  white,  red  under  the  cuticle. 

Gills  pure  white,  subdistant  to  close,  distinct,  rather  broad,  equal, 
broadest  toward  front,  narrowly  adnexed  or  free,  interspaces  venose. 

Stem  4-7  em.  long,  1-2  em.  thick,  white  or  tinged  red,  subequal, 
spongy-stuffed,  even. 

Taste  very  acrid. 

Odor  none. 

Spores  subglobose  to  globose,  7.5-10  microns,  reticulate,  white  in 
mass. 

Cystidia  numerous. 

Our  specimens  of  this  species  are  usually  small.  The  pilei,  rarely, 
if  ever,  reach  a  diameter  of  10  cm. 

24.  Russula  fragile  Fr. 

Pileus  2.5-5  cm.  broad,  very  thin  and  fragile,  convex  then  piano- 
depressed  with  a  thin  viscid  pellicle,  tubercular-striate  on  the  thin 
margin,,  glabrous,  rather  uniform  rosy  or  pale  red,  sometimes  faded 
or  bleached  to  white. 

Flesh  white  under  the  pelliclef  thin. 

Gills  white,  thin,  crowded,  adnexed,  ventricose,  moderately  broad. 

Stem  2.3-5  em.  long,  .5-1  em.  thick,  white,  spongy  then  hollow, 
equal,  fragile. 

Taste  promptly  and  very  acrid. 

Order  none. 

Spores  subglobose,  8-9  microns,  echinulate  with  a  few  reticula- 
tions, white  in  mass. 

Cystidia  very  numerous  and  rounded. 

25.  Russula  fallax  Cke. 

Pileus  3-7  cm.  broad,  thin,  fragile,  color  incarnate  or  pale  rose, 
the  disk  pale  olivaceous  or  livid,  sometimes  darker  or  purplish,  soon 
plane  or  slightly  depressed  on  the  disk,  quite  viscid,  margin  striate 
and  becoming  elevated,  surface  faintly  rugulose  under  lens. 

Flesh  white. 

Gills  white,  unchanged,  subdistant,  attached  by  a  point,  narrow, 
edge  even. 

Stem  3-4  cm.  long,  6-10  mm.  thick,  pure  white,  cylindrical  or  com- 
pressed, equal,  spongy-stuffed,  soon  hollow. 

Taste  promptly  and  very  acrid. 


IOWA  SPECIES  OF  RUSSULA  23 

Odor  none. 

Spores  subglobose,  7-9  x  9-10  microns,  reticulate,  white  in  mass. 

Cystidia  present,  short. 

26.    Russula  albidula  Pk. 

Pileus  2-5  cm.  broad,  white,  broadly  convex,  glabrous,  pellicle 
viscid  and  separable  when  fresh,  margin  even. 

Flesh  white,  subfragile. 

Gills  white,  moderately  crowded,  adnexed,  not  broad,  of  equal 
length,  some  forking  at  base,  interspaces  venose. 

Stem  2.5-4  cm.  long,  8-12  mm.  thick,  white,  equal,  spongy-stuffed, 
even. 

Taste  acrid. 

Odor  none. 

Spores  subglobose,  7-10  microns,  reticulate,  white  in  mass. 

Cystidia  present,  rather  few. 

27.    Russula  sanguinm  Fr. 

Pileus  3-6  cm.  broad,  rather  firm  at  first,  subfragile,  convex-plane 
or  depressed,  rosy-red,  viscid,  margin  acute  and  thin,  pellicle  sub- 
adnate,  easily  separable  on  margin  and  tubercular-striate. 

Flesh  rather  thin,  white,  red  under  pellicle. 

Gills  slightly  adnate,  close  to  subdistant,  equal,  not  broad,  creamy- 
white. 

Stem  4-6  cm.  long,  subequal  or  tapering  downward,  often  eccen- 
tric, white  or  tinged  rosy-red,  spongy-stuffed  then  cavernous,  rather 
fragile,  glabrous,  even. 

Taste  tardily  but  truly  acrid. 

Odor  none. 

Spores  globose,  8-10  microns,  echinulate,  creamy-white  in  mass. 

Cystidia  present,  few. 

28.    Russula  corinthiirubra  Burl. 

Pileus  becoming  plane  or  slightly  depressed  in  the  center,  up  to  9 
cm.  broad,  surface  Corinthian-red,  fading,  the  center  becoming 
tinged  with  maize-yellow,  viscid,  with  the  pellicle  separable  half  way 
to  the  center,  glabrous,  margin  becoming  slightly  striate-tuberculate. 

Flesh  white,  tinged  red  next  to  pellicle. 

Gills  becoming  yellow,  equal,  some  forked  next  to  the  stipe, 
venose-connected,  narrow  at  the  inner  ends,  broad  and  ventricose 
toward  the  outer ;  rather  thick,  close. 


24  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

Stem  white,  firm,  nearly  equal,  4  cm.  long,  1.7  cm.  thick. 
Taste  slowly  acrid. 
Odor  none. 

Spores  subglobose,  7-8  x  9-10  microns,  reticulate,  ochraceous  in 
mass. 

Cystidia  very  numerous,  rounded  at  tip. 

29.     Russula  tenuiceps  Kauff. 

Pileus  7-12  cm.  broad,  thin,  fragile,  convex  to  expanded,  the 
somewhat  viscid  pellicle  easily  separable,  margin  at  first  connivent, 
striate,  deep  rosy  or  blood  red,  sometimes  white,  spotted  or  tinged 
with  orange  blotches,  sometimes  uniform  red,  with  or  without  min- 
ute rugae. 

Flesh  white,  red  under  cuticle,  very  fragile  at  maturity. 

Gills  white,  then  yellow-ochraceous,  crowded,  narrow,  fragile, 
narrowly  adnate  to  free,  few  forked,  interspaces  venose,  equal. 

Stem  fragile,  white  or  rosy-tinged,  spongy-stuffed,  subequal  or 
ventricose,  obscurely  rivulose,  white  within  and  unchanged,  5-9  cm. 
long,  2-2.5  cm.  thick. 

Taste  acrid,  sometimes  tardily  but  very  acrid. 

Odor  not  marked. 

Spores  subglobose,  6-9  x  8-11  microns,  echinulate,  yellow-ochra- 
ceous in  mass. 

Cystidia  present. 

30.     Russula  veternosa  Fr. 

Pileus  5-7.5  cm.  broad,  convex  then  expanded,  with  a  somewhat 
separable  pellicle,  indistinctly  striate  on  the  margin,  deep  rose-red, 
viscid  when  moist. 

Flesh  white,  red  under  the  cuticle. 

Gills  white  at  first,  then  straw-color  or  pale  ochraceous,  narrow, 
adnate,  close,  broader  in  front,  equal  or  few  shorter,  few  forked, 
interspaces  venose. 

Stem  white,  never  red,  equal  or  subequal,  spongy-stuffed,  some- 
what slender,  fragile,  hollow,  even,  4-5  cm.  long,  1-1.5  cm.  thick. 

Taste  very  acrid. 

Odor  none. 

Spores  subglobose,  8-10  microns,  echinulate,  yellowish-ochraceous 
in  mass. 

Cystidia  numerous. 


IOWA  SPECIES  OP  EUSSULA  25 

31.    Russula  subdepallens  Pk. 

Pileus  5-14  cm.  broad,  fragile,  convex  then  plane  and  depressed, 
margin  elevated  in  age,  bright  rosy-red,  shading  into  yellowish 
blotches  as  if  the  red  color  were  put  over  the  yellow,  disk  paler  in 
old  specimens,  disk  dark  red  in  very  young  plants,  with  a  thin 
separable,  viscid  pellicle,  tubercular-striate  on  margin,  obscurely 
wrinkled  elsewhere. 

Flesh  white-rosy  under  cuticle,  becoming  slightly  cinereous,  very 
fragile,  thin. 

Gills  white,  broad  in  front,  narrowed  behind,  adnate,  subdistant, 
few  forked,  interspaces  venose. 

Stem  white,  spongy-stuffed,  rather  stout,  4-10  cm.  long,  1-3  cm. 
thick,  subequal. 

Taste  mild. 

Odor  none. 

Spores  globose,  7.5-8  microns,  echinulate  with  fine  reticulations, 
white  in  mass. 

Cystidia  none. 

32.    Russula  purpurina  Quel,  and  Schultz 

Pileus  3-7  cm,  broad,  fragile,  viscid,  usually  very  viscid,  sub- 
globose  then  expanded  and  slightly  depressed  at  the  disk,  brilliant 
rosy-red  to  blood-red  or  even  darker,  pellicle  somewhat  separable, 
margin  thin  but  not  striate  except  when  fully  expanded,  surface 
when  dry  as  if  with  a  bloom. 

Flesh  white,  red  under  the  cuticle,  thin,  fragile,  unchangeable. 

Gills  white,  later  dingy-white  or  yellowish ;  medium  close  to  sub- 
distant,  adnexed,  not  broad,  broadest  in  front,  mostly  equal,  few  or 
none  forked,  interspaces  sometimes  venose,  edge  floccose-crenulate. 

Stem  rather  long,  5-8  cm.  long,  8-12  mm.  thick,  sprinkled  rosy- 
pink,  equal  or  subequal,  spongy-stuffed,  fragile  but  rather  soft. 

Taste  mild. 

Odor  none. 

Spores  subglobose  to  globose,  6-8  x  8-10  microns,  reticulate,  white 
in  mass. 

Cystidia  present. 

33.    Russula  uncialis  Pk. 
Pileus  2-5  cm.  broad,  thin,  rather  fragile,  convex  then  expanded- 
depressed,  pink  or  bright  flesh-color,  unicolorous,  the  rather  adnate 
pellicle  slightly  separable,  slightly  viscid  when  moist,  pruinose  and 


26  IOWA  STUDIES  IN  NATUEAL  HISTORY 

pulverulent  when  dry,  margin  not  striate  till  old. 

Flesh  white,  pink  under  pellicle,  unchanged. 

Gills  pure  white,  scarcely  changing  with  age,  rather  broad,  broad- 
est in  front,  narrowed  behind  and  adnate ;  subdistant  or  moderately 
close,  distinct,  entire  on  edge,  few  forked,  interspaces  venose. 

Stem  white,  rarely  tinged  pink,  rather  short,  1-3.5  cm.  long,  4-10 
mm.  thick,  spongy-stuffed,  equal,  glabrous. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  7-8  microns,  echinulate  with  a  few  reticula- 
tions, white  in  mass. 

Cystidia  few. 

This  species  with  us  is  generally  fully  5  cm.  broad  but  in  other 
respects  agrees  with  the  descriptions. 

34.     Eussula  Integra  Fr. 

Pileus  5-10  cm.  broad,  firm,  soon  fragile,  discoid,  convex  or  eam- 
panulate  then  piano-depressed,  covered  with  a  viscid  separable  pel- 
Hole,  thin  on  the  margin,  at  length  coarsely  tubercular-striate,  var- 
iable as  to  color  in  different  plants,  colors  dingy  or  sordid,  from  buff 
through  to  reddish-brown  and  dark  dull  red,  fading. 

Flesh  white  not  changing. 

Gills  white  at  first,  then  creamy-yellow  to  buff-ochraceous,  not 
strongly  ochre,  broad,  distant,  equal,  nearly  free. 

Stem  white,  unchanged,  never  red,  soon  quite  fragile,  conic  or 
short-clavate  at  first,  then  subequal  or  ventricose,  spongy-stuffed, 
even. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  8-9  x  9-10  microns,  echinulate,  creamy-yellow 
to  pale  ochraceous  in  mass. 

Cystidia  none. 

35.     Russula  amygdaloides  Kauff. 

Pileus  4-8  cm.  broad,  thin,  medium  size,  ovate  at  first  with  a 
straight  margin,  then  convex-plane  or  depressed,  very  viscid,  fragile, 
pale  rosy-flesh  color  tinged  with  yellow,  sometimes  peach  color,  some- 
times dull  citron-yellow,  varying  in  color  from  young  to  old,  pellicle 
continuous  and  entirely  separable,  margin  becoming  strongly  tuber- 
culate-striate. 

Flesh  thin,  white,  not  changing  color,  soft. 


IOWA  SPECIES  OF  EUSSULA  27 

Gills  bright  ochraceous-yellow,  white  at  first,  rather  narrow, 
broadest  in  front,  narrowed  and  adnexed  behind,  subdistant  at  ma- 
turity, dusted  by  spores. 

Stem  4-8  cm.  long,  1-2  cm.  thick,  subequal  to  ventricose,  soft  and 
fragile,  loosely  stuffed  then  cavernous  (but  not  from  grubs),  white, 
rarely  tinged  with  delicate  pink,  slightly  wrinkled,  subglabrous. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  7-9  microns,  echinulate  with  very  few  reticula- 
tions, bright  ochre-yellow  in  mass. 

Cystidia  very  few. 

36.    Russala  flwiceps  Pk. 

Pileus  convex,  then  expanding  and  slightly  depressed  in  the  cen- 
ter, 5-10  cm.  broad,  surface  amber-yellow  to  golden-yellow,  viscid, 
with  a  separable  pellicle,  glabrous,  margin  even,  when  young,  faint- 
ly striate  when  old. 

Flesh  white. 

Gills  white,  soon  becoming  Naples-yellow  and  dusted  with  spores, 
equal,  simple,  adnate  or  slightly  rounded  next  to  the  stipe,  broader 
at  the  outer  ends,  rather  narrow,  close. 

Stem  white,  equal  or  nearly  so,  stuffed  or  spongy  within,  4-6.5  cm. 
long,  8-12  mm.  thick. 

Taste  mild  or  slightly  acrid. 

Odor  none. 

Spores  subglobose,  8-9  x  9-10  microns,  echinulate,  maize-yellow  in 
mass. 

Cystidia  very  few. 

37.     Bussula  chammleontina  Fr. 

Pileus  2-5  cm.  broad,  rather  small,  fragile,  thin,  piano-depressed, 
with  a  viscid  separable  pellicle,  margin  even  at  first  then  striatulate, 
color  varying  for  different  pilei,  mostly  same  shade  of  red,  purple, 
etc.,  fading  to  yellowish  especially  on  disk. 

Flesh  white,  thin. 

Gills  thin,  crowded  or  close,  adnexed  or  almost  free,  equal,  rather 
broad,  sometimes  almost  narrow,  few  forked,  interspaces  venose, 
ochraceous  or  ochraceous  yellow. 

Stem  2-5  cm.  long,  4-6  mm.  thick,  white,  spongy-stuffed  then  hol- 
low, slender,  equal  or  subequal  to  subventricose,  sometimes  sub- 
clavate,  even  or  obscurely  rivulose. 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

Taste  mild. 
Odor  none. 

Spore  subglobose  to  globose,  6-8  x  8-10  microns,  echinulate  with  a 
few  reticulations,  ochraceous  in  mass. 
Cystidia  present. 

38.    Russula  humidicola  Burl. 

Pileus  broadly  convex,  soon  becoming  depressed  in  the  center,  up 
to  6  cm.  broad,  surface  varying  in  color  from  salmon,  reddish- 
salmon,  and  yellowish  salmon  to  Morocco-red  in  the  center,  some- 
times fading,  viscid,  with  pellicle  separable  except  on  disk,  glabrous, 
margin  drooping,  soon  tuberculate-striate. 

Flesh  thin,  white  fragile. 

Gills  white,  becoming  cream-colored,  equal,  rarely  forking  next 
to  the  stipe,  interveined,  acute,  narrow  and  nearly  free  at  the  inner 
ends,  broad  and  rounded  at  the  outer,  close,  thin,  pruinose. 

Stem  white,  nearly  equal,  spongy,  then  hollow,  3-5  cm.  long,  5-10 
mm.  thick. 

Taste  mild. 

Odor  none. 

Spores  globose  to  elliptic,  5-6  x  7  microns,  echinulate  with  few 
reticulations,  maize-yellow  in  mass. 

Cystidia  present,  short  and  blunt. 

39.     Russula  luteobasis  Pk. 

Pileus  convex,  then  nearly  plane,  2.5-8  cm.  broad,  surface  at  first 
rosy  or  red,  then  paler ;  yellowish  in  center,  viscid  when  wet,  cuticle 
separable,  glabrous,  margin  even,  indistinctly  striate  when  old. 

Flesh  white  or  whitish. 

Gills  white  to  cream-yellow  or  pale-ochraceous  when  old  or  in  dy- 
ing, equal,  not  forking,  except  near  the  stipe,  adnexed  to  adnate, 
rather  close,  broad. 

Stem  white,  yellow  to  orange-yellow  at  base,  subequal,  stuffed, 
2.5-7  cm.  long,  .4-2  cm.  thick. 

Taste  mild. 

Odor  none. 

Spores  subglobose,  7-8  x  8-9  microns  in  diameter,  reticulate,  yel- 
low-ochraceous  in  mass. 

Cystidia  none. 


IOWA  SPECIES  OP  RUSSULA  29 

40.    Russula  roseipes  (Seer.)  Bres. 

Pileus  2.5-5  cm.  broad,  thin,  fragile,  convex  then  piano-depressed, 
with  a  viscid,  separable  pellicle,  margin  tubercular-striate  when  ma- 
ture, soon  dry,  rosy-red  or  flesh-red,  disk  tending  to  ochre-yellowish. 

Flesh  white,  thin,  unchanged. 

Gills  soon  truly  ochraceous,  subdistant,  mostly  equal,  broadest  in 
front,  ventricose,  narrowly  adnate  or  almost  free,  few  forked,  inter- 
spaces venose. 

Stem  white  and  rosy-sprinkled,  stuffed  then  cavernous,  equal  or 
tapering  upward,  even,  2.5-5  cm.  long,  5-12  mm.  thick. 

Taste  mild. 

Odor  none  or  pleasant. 

Spores  subglobose  to  globose,  7-8  x  9-10,  microns,  echinulate  with 
few  reticulations,  ochraceous  in  mass. 

Cystidia  none. 


BIBLIOGRAPHY 

1.  Beardslee,  H.  C,  The  Bussulas  of  North  Carolina.    Jour.  Elisha  Mitchell 

Sci.  Soc.  33:  147-197,  1918. 

2.  Burlingham,  G.  &,  Kussula.    In  N.  A.  Flora.    9:201-236,1915. 

3.  Kauffman,  C.  H.,  Agaricaceae  of  Michigan,  1918. 

4.  Melzer,  V.,  L  'ornementation  des  spores  de  Russula.    Bull.  soc.  Myc.  France. 

40:  78-81,  1924. 

5.  Persoon,  C.  H.,  Synopsis  methodica  fungorum.    438-447,  1801. 

6.  Shimek,  B.,  Plant  Geography  of  the  Lake  Okoboji  region.    Bull.  Lab.  Nat. 

Hist.,  Uuiv.  of  Iowa.    7:  1-90,  1915. 


1. 

E. 

albidula 

2. 

R. 

alutacea 

3. 

R. 

amygdaloides 

4. 

R. 

atropurpurea 

5. 

R. 

borealis 

6. 

R. 

chamseleontina 

7. 

R. 

corinthiirubra 

8. 

R. 

CTustosa 

9. 

R. 

decolorans 

10. 

R. 

emetica 

11. 

R. 

fallax 

12. 

R. 

flava 

13. 

R. 

flaviceps 

14. 

R. 

foetentula 

15. 

R. 

fragilis 

16. 

R. 

humidicola 

17. 

R. 

integra 

18. 

R. 

lepida 

19. 

R. 

luteobasis 

20. 

R. 

nauseosa 

EXPLANATION  OF  PLATE 
Spores  of  Russula 

21.  R.  nigricans 

22.  R.  obscura 

23.  R.  ochraleucoides 

24.  R.  ochrophylla 

25.  R.  pectinatoides 

26.  R.  purpurina 

27.  R.  raoultii 

28.  R.  roseipes 

29.  R.  rubescens 

30.  R.  sanguinea 

31.  R.  subdepallens 

32.  R.  subpunctata 

33.  R.  tenuiceps 

34.  R.  uncialis 

35.  R.  variata 

36.  R.  veternosa 

37.  R.  virescens 

38.  R.  viridella 

39.  R.  xerampelina 


30 


^ 


OCCURRENCE  OF  MYCORRHIZA  IN  IOWA 
FOREST  PLANTS 

M.  L.  IjOHMAN 

INTRODUCTION 

The  root-fungus  association  in  the  higher  plants  has  had  attention 
in  botanical  literature  since  the  middle  of  the  nineteenth  century. 
The  classical  investigations  of  Kamienski  (1881),  Frank  (1885), 
and  Stahl  (1900)  gave  an  impetus  to  this  phase  of  mycological  and 
physiological  research  which  has  resulted  in  a  continuous  series  of 
papers  up  to  the  present  time.  Most  investigations  have  been  made 
by  European  workers,  and  the  most  recent  studies  are  those  of 
Demeter  (2),  Melin  (9,  10,  11,  12,  13),  and  Peyronel  (17)  on  the 
continent,  and  Eayner  (18,  19,  20,  21)  in  England. 

The  term  "mycorrhiza"  was  first  used  by  Frank  (3)  to  desig- 
nate that  condition  of  a  fungus-root  system  in  which  the  fungus 
mycelium  forms  a  weft  of  interwoven  hyphae  about  the  root-tips 
of  the  higher  plants.  This  term  was  adopted  by  later  workers  and 
it  is  the  accepted  term  to-day,  although  it  has  been  extended  to 
include  those  conditions  in  which  the  fungus  hyphse  are  present 
in  parts  other  than  the  root,  or  throughout  the  entire  plant.  The 
term  "mycotrophic"  has  been  suggested  as  more  accurate,  especial- 
ly when  applied  to  such  plants  as  Corallorrhiza,  in  which  there  are 
no  roots  (Skene,  22).  "Mycorrhiza"  has  also  been  used  quite 
loosely  by  some  writers  to  imply  in  one  instance  the  fungus-root 
system,  and  in  others  the  fungus  alone,  which,  of  course,  is  mis- 
leading and  incorrect. 

The  technique  involved  is  complicated,  and  it  is  exceedingly 
difficult  to  identify  the  fungus  found  in  mycorrhizal  relationship 
with  the  root  of  a  particular  plant.  Considerable  care  must  be 
exercised  to  succeed  in  getting  the  fungus  in  culture.1  Whether 
in  culture  or  not,  not  all  mycorrhizal  fungi  produce  fruit  bodies, 
but  the  mycelium  may  remain  sterile  in  the  soil  for  years,  con- 
tinuing to  form  mycorrhiza.  The  method  of  tracing  the  mycelium 
from  the  fruiting  body,  through  the  soil,  to  the  root  of  the  higher 
plant  has  been  employed  as  a  means  of  identification,  but  it  is 


i  See  Rayner  (18)  for  culture  methods. 

33 


34  IOWA  STUDIES  IN  NATURAL  HISTORY 

believed  that  such  methods  allow  considerable  opportunity  for 
error.  Paulson  (16)  states  that  the  bulk  of  mycorrhiza  is  found 
in  decaying  leaves  near  the  surface  layers  where  decomposition  is 
not  far  advanced.  Thus  the  soil  is  permeated  with  the  mycelium 
of  soil  fungi,  many  of  which  form  mycorrhizal  connnections  with 
the  higher  plants. 

Types  of  Mycorrhiza 

In  most  literature  the  types  of  mycorrhizal  development  are  given 
as  ectotrophic  and  endotrophic,  signifying  respectively  that  the 
fungus  is  growing  on  the  outside  or  on  the  inside  of  the  root  of 
the  higher  plant.  A  third  quite  peculiar  type  of  development  has 
been  reported,  i.e.,  those  endotrophic  forms  developing  the  charac- 
teristic vesicles  and  arbuscles.  Rayner  (20)  believes  the  distinction 
between  ectotrophic  and  endotrophic  forms  is  in  the  degree  of  in- 
fection of  the  root  by  the  fungus.  This  suggests  a  possible  tran- 
sition on  the  part  of  a  mycorrhiza-f orming  fungus  from  the  endotro- 
phic character  to  the  ectotrophic,  and  that  a  given  fungus  may  be 
endotrophic  with  one  plant,  and  ectotrophic  with  another.  It  is 
possible  that  a  mycorrhiza-f  orming  fungus  of  a  general  endotrophic 
habit  may  form  vesicles  or  arbuscles  in  one  plant,  and  not  in  an- 
other (Demeter,  2). 

The  ectotrophic  form  (fig.  46,  pi.  8)  is  readily  noted  since  it 
occurs  commonly  in  connection  with  the  roots  of  many  common 
forest  trees  such  as  beech  and  oak,  also  pine,  larch  and  other  coni- 
fers, the  root  having  a  coral-like  appearance,  being  short,  thick- 
ened, profusely  branched,  and  with  root  hairs  usually  lacking  or 
few.  This  was  the  type  noticed  by  Frank  which  led  to  his  further 
investigations.  He  regarded  the  outer  part  of  the  root  simply  as 
a  fungus  sclerotium,  and  described  it  as  a  pseudoparenchymous- 
like  layer,  formed  by  the  massed  hyphae,  resulting  in  a  thick  mantle 
or  weft  of  fungus  mycelium  about  the  root  of  the  higher  plant. 
The  fungus  sends  haustoria  in  between  the  epidermal  cells,  and 
these  penetrate  the  root  between  the  outer  cortical  cells.  Melin 
(1921)  has  shown  for  pine  and  spruce  that  infection  in  this  ecto- 
trophic form  takes  place  through  the  root  hairs  or  epidermal  layer 
of  cells,  and  that  the  fungus  first  exists  inside  the  cortical  cells, 
but  after  digestion  commences,  the  hyphae  pass  between  the  cells 
of  the  epidermis  and  form  the  typical  mantle. 

In  the  endotrophic  mycorrhiza   (15)   the  hyphae  penetrate  the 


MYCORRHIZA  IN  FOREST  PLANTS        35 

root  and  develop  within  the  cortical  cells,  obtaining  nourishment 
there.  In  such  cases  the  mycelium  may  be  intercellular,  intra- 
cellular, or  both,  as  observed  by  West  (24)  in  mycorrhiza  of  the 
Marattiaceae.  The  fungus  in  many  forms  of  endotrophic  mycorrhiza 
is  thought  to  be  a  Phycomycete  or  a  closely  allied  form.  Peyronel 
is  of  the  opinion  that  the  mycelium  of  these  phycomycetoid  endo- 
trophs  forms  in  humus  soil  a  continuous  network  which  involves 
the  root-system  of  the  higher  plants,  passing  from  one  to  another, 
and  also  that  these  phycomycetoid  endotrophs  live  a  saprophytic 
existence,  continuing  their  existence  and  development  in  the  cor- 
tical tissues  of  the  root  after  the  death  of  the  latter.  In  most  endo- 
trophic mycorrhiza  the  fungus  forms  haustorium-like  arbuscles  and 
spore-like  vesicles  (17),  both  of  which  will  be  discussed  later.  This 
type  seems  to  differ  sharply  from  the  endotrophic  mycorrhizal 
fungus  of  the  orchids  which  has  been  isolated  and  cultivated,  and 
is  regarded  as  belonging  to  the  genus  Rhizoctonia. 

Rayner  (18,  19,  20)  has  worked  with  an  endotrophic  fungus  in 
Calluna  vulgaris  which  affects  all  parts  of  the  plant;  root,  stem, 
leaf,  flower,  and  fruit.  The  distinction  made  by  her  between  ecto- 
trophic  and  endotrophic  forms  is  one  of  degree  of  infection  only. 
The  hyphae  on  entering  the  root  cell  seem  to  be  attracted  towards 
the  nucleus.  Branching  then  occurs  and  the  cells  are  filled  with 
large  hyphae  which  are  capable  of  absorbing  material  from  the  cell 
as  well  as  from  the  external  mycelium. 

In  many  endotrophic  mycorrhiza,  especially  when  the  mycorrhizal 
fungus  suggests  a  Phycomycete,  the  peculiar  vesicles  and  arbuscles 
(figs.  44  and  45,  pi.  8)  first  described  by  Gallaud  (4)  are  found. 
Peyronel  (17)  has  observed  these  structures  in  endotrophic  fungi, 
not,  however,  in  orchids,  and  he  believes  the  fungus  concerned  to 
be  a  Phycomycete,  close  to  the  genus  Endogone.  West  (24)  reports 
their  presence  in  the  mycorrhiza  of  the  Marattiaceae.  A  complete 
discussion  of  these  forms  is  given  by  Demeter  (2)  in  connection 
with  his  studies  on  the  mycorrhizal  fungus  of  Vinca  minor,  Vince- 
toxicum  officinale,  and  Asclepias  cornuti.  He  believes  the  fungus 
in  these  species  to  be  the  same  as  that  found  in  the  orchids,  but 
in  these  species  it  develops  the  vesicles  and  arbuscles.  Apparently 
these  peculiar  endotrophic  structures  have  nowhere  been  reported 
for  the  orchids.  Terminal  and  intercalary  vesicles  may  form  on 
either  intercellular  or  intracellular  hyphae,  and  appear  to  be  storage 
organs.    But  more  important  than  the  vesicles,  according  to  Deme- 


36  IOWA  STUDIES  IN  NATURAL  HISTORY 

ter  are  the  tree-like  structures  which  Gallaud  termed  "arbuscles." 
These  arbuscles  are  formed  by  a  cloud  of  fine  granules  about  the 
tips  of  the  fungus  branches.  These  are  regarded  by  Demeter  as 
-apparently  a  protein  precipitate  formed  by  the  mixing  of  the  proto- 
plasm of  the  cell  of  the  higher  plant  and  that  of  the  fungus  when 
the  tips  of  the  fungus  branches  burst.  The  granules  later  diffuse 
throughout  the  cell,  and  finally  unite  to  form  organized  bodies — 
the  so-called  '  *  sporangioles. ' '  He  suggests  the  name  * '  Plasmoptysic- 
mycorrhiza"  for  this  type  of  fungus. 

Magrou  (8)  found  vesicles  in  the  endotroph  of  the  wild  potato 
and  arbuscles  in  the  fungus  of  Mercurialis  annua.  Upon  inoculat- 
ing Solanum  tuberosum  with  Mucor  solani  he  obtained  terminal 
and  intercalary  vesicles  resembling  very  much  those  of  the  endo- 
troph found  in  nature. 

Symbiosis  in  Myc'orrhizal  Connection 
Several  theories  have  been  advanced  concerning  the  nutritive 
relation  existing  in  mycorrhiza,  and  in  connection  with  each  a  con- 
siderable amount  of  experimental  evidence  has  accumulated.  It 
is  still  a  question  as  to  whether  a  mycorrhizal  fungus  is  in  any  way 
parasitic  on  the  higher  plant,  or  whether  there  is  established  a 
state  of  true  symbiosis,  and  if  so,  in  what  way  the  higher  plant 
benefits  by  the  presence  of  the  fungus.  It  is  undoubtedly  true  that 
no  one  rule  can  be  set  down  for  mycorrhiza  in  general,  and  that 
this  physiological  relationship  varies  between  different  plants  and 
the  same  fungus ;  and  between  different  fungi  with  the  same  plant. 
In  any  case  there  is  probably  a  time  in  mycorrhizal  development 
when  the  relationship  is  parasitic,  and  when  it  is  symbiotic.  In 
other  words,  such  a  physiological  relationship  is  highly  variable. 

Magrou  (8)  defines  symbiosis  as  that  condition  where  both 
participants  (higher  plant  and  fungus)  are  in  an  equal  state  of 
reciprocity.  The  plants  resist  the  attack  of  the  fungus  by  some 
mechanical  means  of  rendering  themselves  immune,  such  as  the 
suffocation  of  the  fungus  by  the  development  of  cell  structure. 
Miehe  (14)  believes  that  the  fungus  on  Casuarina  equisetifolia  is 
a  typical  symbiont,  changing  nitrogenous  materials  already  derived 
from  the  soil  into  such  forms  as  can  be  used  by  the  plant. 

Molisch  (15)  in  discussing  the  general  physiological  conditions 
states  that  perhaps  the  fungus  simply  assimilates  free  nitrogen  as 
do  the  nodule-bacteria  in  the  Leguminosse,  or  that  it  aids  in  the 


MYCORRHIZA  IN  FOREST  PLANTS        37 

nutrition  of  the  higher  plant  to  some  extent  by  making  undigestible 
humus  materials  digestible,  the  plant  thus  obtaining  nourishment 
through  the  fungus.  In  such  cases  the  fungus  also  obtains  organic 
material  from  the  plant.  He  also  suggests  the  idea  that  the  fungus 
digests  itself,  and  that  the  higher  plant  may  in  this  way  assimilate* 
organic  and  inorganic  materials.  Whether  or  not  soil  fungi  def- 
initely assimilate  free  nitrogen  is  still  a  problem  for  research,  al- 
though some  positive  and  a  considerable  amount  of  negative  evi- 
dence has  been  obtained  (5,  22). 

Rayner  (19)  in  discussing  the  nutrition  of  mycorrhizal  plants; 
in  connection  with  the  endotroph  of  Calluna  vulgaris  states  em- 
phatically that  the  fungus  has  the  general  appearance  of  a  parasite, 
and  can  act  as  such  under  certain  conditions.  She  concludes  that 
the  reciprocity  involved  in  the  formation  of  active  mycorrhiza  as 
represented  in  Calluna  vulgaris  marks  a  relatively  advanced  stage* 
of  relationship,  implying  an  extremely  intimate  association,  and 
resulting  in  a  " balance-of -profit' '  for  the  higher  plant.  The  view 
put  forward  by  the  same  author  (18)  in  discussing  the  obligate 
symbiosis  in  Calluna  vulgaris,  is  that  the  first  step  towards  the  for- 
mation of  mycorrhiza  involves  a  temporary  modification  of  the 
parasitic  habit  on  the  part  of  the  fungus  concerned. 

Melin  (11,  13)  upholds  the  fungus-symbiont  theory  for  the  plants, 
with  which  he  has  worked.  He  believes  that  various  symbionts  of 
forest  trees  may  enable  their  partners  to  assimilate  the  different 
organic  nitrogenous  compounds  of  the  soil  with  a  varying  degree 
of  ease,  and  that  certain  species  of  fungi  can  utilize  the  complex: 
albumin  bodies  of  the  humus  layer  better  than  their  disintegration 
products;  while  others  more  readily  assimilate  the  latter.  Melin 
produced  ectotrophic  mycorrhiza  in  culture  on  the  birch  with 
Boletus  scaber,  and  on  the  ash  with  B.  rufus.  The  relationship 
ascribed  is  pure  symbiosis,  the  higher  partner  deriving  much  food 
from  the  digestion  of  the  hyphse  of  the  mycorrhizal  fungus. 

The  establishment  of  a  state  of  true  symbiosis  is  referred  to  by 
Thomas  (23)  in  his  paper  on  the  genus  Corallorrhiza,  and  recent 
work  by  Melin  (10)  has  led  the  latter  to  believe  that  in  many  cases 
the  higher  plant  and  the  fungus  do  live  in  a  true  state  of  symbiosis, 
both  the  fungus  and  the  higher  plant  being  benefited  by  this  close 
morphological  and  physiological  association.  He  bases  his  con- 
clusion, first,  on  results  of  synthetic  culture  experiments;  second^ 


38  IOWA  STUDIES  IN  NATURAL  HISTORY 

on  observations  made  under  natural  conditions;  and  third,  on  an- 
atomical structure  of  the  mycorrhiza. 

It  was  long  believed  that  the  fungus  relationship  in  the  orchids 
was  one  of  true  mycosymbiosis,  and  that  the  fungus  was  absolutely 
essential  to  germination  and  growth  of  the  orchid.  Knudson  (7) 
has  demonstrated  recently  that  the  germinating  orchid  seed  is  bene- 
fited by  the  presence  of  the  fungus  in  that  the  fungus  increases  the 
hydrogen-ion  concentration,  and  changes  complex  carbohydrates 
into  forms  more  available.  Uninfected  seeds,  in  solutions  with  an 
acidity  equivalent  to  that  produced  by  the  fungus,  germinated  just 
as  well  as  infected  seeds  in  control  solutions  which  were  less  acid, 
and  in  which  uninoculated  seeds  would  not  germinate.  His  unin- 
oculated  control  cultures  had  a  pH  value  of  5.7,  and  on  inoculation 
of  such  cultures  with  the  fungus  the  acidity  was  increased  so  that 
the  pH  value  ranged  from  4.2  to  4.4. 

Thus,  in  general,  it  may  be  said  that  the  early  workers  believed 
that  there  was  a  state  of  true  reciprocity  existing  between  the  high- 
er plant  and  the  mycorrhizal  fungus.  There  was  then  a  period  in 
which  the  theory  of  parasitism  on  the  part  of  the  fungus  was  ad- 
vanced, followed  by  more  recent  work  in  which  the  relationship  was 
again  thought  to  be  one  of  true  symbiosis  as  defined  by  Melin. 

METHODS   USED   IN   COLLECTION  AND   PREPARATION 

FOR  STUDY 

The  purpose  of  this  research  was  to  make  as  extensive  a  survey 
as  possible,  in  the  time  at  my  disposal,  of  the  occurrence  and  nature 
of  mycorrhiza  in  Iowa  forest  plants.  Thus  the  methods  used  in 
collecting,  preliminary  study  of  roots  and  soil,  fixing,  and  staining, 
were  those  most  convenient  for  use  in  such  a  survey.  The  intention 
was  to  examine  and  study  the  roots  of  as  many  plants  belonging  to 
representative  families  as  possible,  without  intensive  study  of  any 
one  particular  plant. 

All  but  one  of  the  collections  were  made  from  April  to  October, 
1925.  The  exception  was  an  abundant  supply  of  CorallorrJiizay 
collected  in  September,  1924.  Collections  were  made  in  the  typical 
Iowa  forests  of  the  river  valleys  of  Johnson  and  Iowa  counties,  and 
in  the  forests  of  the  lake  borderlands  of  Dickinson  County,  with  a 
few  collections  from  open  plant  associations  about  West  Okoboji 
Lake.  Plants  collected  in  the  field  were  taken  into  the  laboratory 
with  a  considerable  quantity  of  soil  attached,  the  pH  reading  of  the 


MYCORRHIZA  IN  FOREST  PLANTS       39 

soil  solution  was  made,  and  the  plants  were  then  placed  in  the 
refrigerator  until  the  preliminary  examination  could  be  made. 

The  pH  values  of  the  soil  solutions  were  determined  as  soon  as 
the  material  was  brought  from  the  field.  Experiment  showed  that 
a  reading  of  the  hydrogen-ion  concentration  of  the  soil  solution  in 
the  field  was  not  necessary,  and  that  soils  kept  in  the  refrigerator 
for  from  twenty-four  to  thirty-six  hours  exhibited  surprisingly  little 
variation  in  the  pH  reading  from  that  taken  in  the  field,  or  imme- 
diately upon  arriving  at  the  laboratory,  which  was  rarely  more  than 
four  hours  from  the  time  of  collection.  In  obtaining  the  pH  value, 
about  5  cc.  of  soil  was  well  mixed  by  shaking  in  a  test  tube  with 
20  cc.  of  neutral  distilled  water.  This  was  allowed  to  stand  until 
the  turbidity  of  the  soil  solution  was  considerably  reduced,  ten  to 
fifteen  minutes  being  sufficient.  The  determination  of  the  hydrogen- 
ion  concentration  was  made  with  the  standard  indicators  to  one 
decimal  place.  Such  a  method,  of  course,  is  not  free  from  error, 
but  in  general  the  error  involved  was  compensating,  and  the  relative 
acidity  or  alkalinity  of  the  various  soils  tested  was  sufficiently 
accurate  for  the  purposes  of  such  a  survey.  In  general,  the  soil 
taken  for  the  pH  reading  was  that  about  those  roots  exhibiting  the 
usual  external  characteristics  of  mycorrhiza,  or,  in  plants  which 
did  not  disclose  mycorrhiza  in  external  appearance  of  the  roots,  the 
soil  sample  was  usually  taken  at  a  depth  of  several  inches.  In  sev- 
eral collections,  as  a  matter  of  experiment,  pH  readings  of  the  soil 
solutions  were  made  from  the  surface  layer,  and  also  from  various 
depths  down  to  a  depth  of  six  and  eight  inches,  and  little  variation 
in  the  pH  values  was  revealed. 

A  preliminary  examination  was  made  on  all  plants  collected, 
which  involved  a  careful  study  of  the  external  characters  of  the 
roots,  and  a  microscopic  examination  of  the  internal  structure  by 
the  study  of  free-hand  sections.  Note  was  taken  of  the  general 
appearance,  form,  root-hair  formation,  and  of  any  traces  of  fungus 
hyphae  found  externally  or  internally.  Free-hand  sections  were 
made  across  the  root,  beginning  at  the  root-tip  and  then  at  intervals 
in  the  older  root  parts  up  to  3-4  cm.  from  the  tip  until  no  trace  of 
fungus  hyphae  was  found.  The  staining  of  free-hand  sections  with 
Gram's  iodine  solution,  or  by  an  aqueous  solution  of  eosin,  or  both, 
was  found  very  useful.  Roots  of  collections  which  disclosed  ecto- 
trophic  or  endotrophic  fungus  hyphse  in  this  examination  were  fixed 
and  preserved  for  further  study. 


40  IOWA  STUDIES  IN  NATURAL  HISTORY 

Several  attempts  were  made,  with  the  usual  precautions  and 
methods  of  sterilization,  to  obtain  cultures  of  the  ectotrophic  fungus, 
present  on  the  roots  of  Ostrya  virginiana  and  Quercus  macrocarpa, 
but  these  were  unsuccessful. 

Chromo-acetic  acid  (1  per  cent)  was  used  in  general  as  a  fixing 
agent,  although  several  collections  were  fixed  and  preserved  in 
formalin-alcohol.  Material  fixed  in  chromo-acetic  acid  was  washed, 
and  then  preserved  in  5  per  cent  formalin  solution  until  further 
study.  Sections  of  different  parts  of  roots  of  the  same  collection 
were  kept  in  separate  vials.  Preserved  material  for  microscopic 
study  was  run  through  the  complete  series  of  alcohols,  at  10  per 
cent  intervals,  for  dehydration,  with  four  steps  from  absolute  alco- 
hol to  pure  xylol,  and  was  imbedded  in  48°  paraffin.  Longitudinal 
sections  were  made  of  roots  of  all  plants  which  disclosed  mycorrhiza 
in  the  preliminary  examination,  as  a  check  on  such  findings,  and 
cross  sections  were  made  of  roots  of  those  collections  which  disclosed 
outstanding  mycorrhizal  types  in  the  longitudinal  sections.  The 
microtome  sections  were  cut  from  10  to  15  microns,  the  15  micron 
sections  being  more  satisfactory  for  this  particular  study.  Good 
paraffin  ribbons  were  obtained  showing  no  great  amount  of  tearing 
of  vascular  and  cortical  tissue  in  either  longitudinal  or  cross  sec- 
tions of  such  woody  roots  as  those  of  oak,  ash,  hornbeam,  cotton- 
wood,  and  the  older  roots  of  ferns,  without  special  treatment. 
Land's  albumin  fixative  as  given  by  Chamberlain  was  the  only 
material  used  in  fixing  the  paraffin  sections  to  the  slide.  This 
proved  very  successful  in  general,  but  surprisingly  unsuccessful 
in  the  case  of  two  ferns.  In  those  sections  of  Adiantum  pedatum 
which  possessed  an  ectotrophic  fungus  layer  of  considerable  thick- 
ness, the  weft  of  fungus  hyphae  did  not  adhere  to  the  slide  well; 
and  in  the  material  of  Osmunda  claytoniana  which  possessed  an 
endotrophic  fungus,  the  cells  containing  the  disorganizing  fungus 
hyphae  were  mostly  lost. 

No  attempt  was  made  to  experiment  with  various  stains,  but  since 
roots  of  many  different  species  of  plants,  and  different  collections 
of  the  same  species  were  being  investigated,  Flemming  's  triple  stain 
was  used  as  the  general  stain.  In  this  the  safranin  was  made  from 
equal  parts  of  a  saturated  solution  in  95  per  cent  alcohol  and  a 
saturated  aqueous  solution,  with  1  per  cent  aqueous  solutions  of 
gentian  violet  and  orange  G.  In  cases  where  more  careful  study 
was  desired,  iron-alum  hematoxylin  counterstained  with  1  per  cent 


MYCORRHIZA  IN  FOREST  PLANTS  41 

aqueous  solutions  of  orange  6  or  erythrosin  was  used  as  a  check. 
The  hematoxylin  proved  the  better  stain  in  the  case  of  most  ecto- 
trophic  fungi,  and  also  for  those  orchids  which  exhibited  endo- 
trophic  fungus  mycelium. 

RESULTS 

Seventy  plant  collections  were  made,  forty-three  of  which  dis- 
closed fungi  in  mycorrhiza-like  relationship,  the  other  twenty-seven 
collections  being  negative.  Of  the  collections  all  but  one  (the  stock 
collections  of  Corallorrhiza)  were  made  between  April  13  and 
October  10,  1925,  in  Dickinson  and  Johnson  counties,  with  one 
collection  from  Iowa  County.  The  localities  worked  in  these  three 
counties  are  covered  with  typical  Iowa  forests.  Most  of  the  Johnson 
County  collections,  and  the  collection  from  Iowa  County  were  made 
in  the  months  of  April  and  May.  The  temperature  was  practically 
normal  for  southeastern  Iowa,  but  the  rainfall  until  June  was  above 
the  average.  Conditions  were  favorable  for  an  abundant  fungus 
flora  and  especially  for  mycelial  growth  in  the  soil.  Eight  col- 
lections were  made  in  Johnson  County  in  September  and  October, 
following  an  extremely  warm  summer  with  a  normal  amount  and 
distribution  of  rainfall.  Warm  weather  continued  until  about 
October  15,  when  heavy  frosts,  early  snows,  and  frozen  ground 
prevented  any  more  collecting.  The  ground  was  slightly  frozen 
when  the  last  collections  were  made. 

The  collections  in  Dickinson  County  were  made  in  June  and  July. 
Cool,  wet  weather  prevailed  the  latter  part  of  June,  but  the  month 
of  July  was  very  hot  and  dry.  Dickinson  County  had  an  extremely 
dry  spring.  Conspicuous  fungi  were  very  scarce  in  the  Okoboji 
region  in  the  summer  of  1925,  only  a  few  specimens  of  the  very 
common  genera  being  found  during  the  entire  summer.  It  is  ex- 
tremely probable  that  this  was  reflected  in  the  growth  and  fewer 
numbers  of  soil  fungi. 

The  total  of  seventy  plant  collections  made  represented  twenty- 
one  families,  thirty-four  genera,  and  forty  species.  The  results  of 
these  collections,  including  field  notes,  the  most  important  notes 
from  preliminary  examinations,  and  examinations  of  prepared 
slides,  can  be  best  correlated  in  tabular  form.  In  Table  I,  which 
concerns  those  species  in  which  mycorrhiza  was  present  in  all  ex- 
aminations, the  arrangement  is  in  phylogenetic  order2  according 

2  The  nomenclature  and  phylogenetic  order  used  is  that  of  Gray's  Manual 
of  Botany;  Ed.  7. 


42 


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MYCORRHIZA  IN  FOREST  PLANTS       47 

to  families,  and  genera  within  each  family.  With  each  collection 
is  given  the  hydrogen-ion  concentration  of  the  soil  solution;  the 
distinctive  characters  of  the  root-fungus  association,  and  of  the 
fungus  involved;  root  characters  of  the  higher  plant;  the  habitat 
of  the  higher  plant ;  and  the  place  and  date  of  collection. 

Table  II  lists  in  phylogenetic  order  those  species  in  which  mycor- 
rhiza  were  found  in  some  but  not  all  specimens  examined,  giving 
the  number  of  collections  of  each ;  the  pH  of  the  soil  solution ;  the 
habitat  of  the  higher  plant;  and  the  place  and  date  of  collection. 
In  those  cases  which  revealed  mycorrhiza  the  fungal  condition  is 
given. 

Table  III  lists  in  like  manner  those  species  in  which  no  mycqr- 
rhizal  condition  was  found  giving  for  each  collection  the  hydrogen- 
ion  concentration  of  the  soil  solution;  the  habitat  of  the  higher 
plant,  and  its  important  characters;  and  the  place  and  date  of 
collection. 

DISCUSSION 

The  endotroph  found  in  the  two  examinations  of  Melilotus  proved 
of  interest,  as  mycorrhiza  has  been  reported  for  the  Leguminosae 
only  since  1923  (Jones,  6).  Atkinson  (1)  reported  on  a  microsym- 
biont  in  the  root  tubercle  of  Vivid  saliva  in  1893,  but  did  not  refer 
to  it  as  a  fungus.  His  figures  of  this  microsymbiont  clearly  show 
it  to  be  similar  to  the  mycorrhizal,  phycomycetoid,  endotrophic 
fungi  with  the  arbuscle  formations.  Jones  has  found  mycorrhiza- 
like  fungi  in  the  roots  of  fifteen  species  of  Leguminosae.  The  fungus 
is  reported  as  a  Phycomycete,  occasionally  forming  vesicles  and 
arbuscles.  The  roots  of  Melilotus  which  I  examined  possessed 
bacterial  nodules,  and  the  fungus  endotroph  was  found  in  the  cor- 
tical and  epidermal  cells  some  distance  above  the  nodules  (figs. 
27,  28 ;  pi.  5) .  No  trace  of  a  fungus  was  found  in  the  hypertrophied 
cells  of  the  nodules. 

The  two  collections  of  Hepatica  were  from  widely  separated 
localities,  one  being  from  a  ravine  in  a  dense  woods,  and  the  other 
from  a  north-exposed,  limestone  cliff.  The  branching,  phycomy- 
cetoid, endotroph  found  in  both  was  apparently  the  same  fungus, 
found  always  in  roots  that  were  distorted  and  wanting  in  root  hairs. 
No  trace  of  a  fungus  was  found  more  than  1  cm.  from  the  root  tip 
(figs.  24,  25;  pi.  5).    On  the  same  plants  no  trace  of  a  fungus  was 


48  IOWA  STUDIES  IN  NATUEAL  HISTORY 

found  in  those  roots  which  possessed  root  hairs  and  appeared 
normal. 

The  fungus  found  in  Orchis  (fig.  18;  pi.  4),  and  in  Corallorrhiza 
(pi.  3)  appeared  to  be  the  typical  orchid  fungus  as  described  by 
Knudson  (7).  This  was  very  abundant  in  the  subterranean  parts 
of  Corallorrhiza  in  various  stages  of  infection  by  the  fungus,  and 
of  digestion  of  the  fungus  by  the  host.  The  two  collections  of 
Orchis  were  from  different  localities,  one  being  from  a  group  of 
plants  in  a  rather  dense  woods,  and  the  other  being  a  lone  specimen 
from  an  open  coppice  growth.  Both  specimens  possessed  good  root 
hair  development,  and  the  fungus  of  the  former  was  confined  to 
but  two  cortical  cells  in  one  root  (of  the  six  roots  examined),  while 
the  latter  showed  abundant  endotrophic  hyphse  about  2  cm.  from 
the  tips  of  the  roots.  The  first  was  collected  April  19,  and  the  sec- 
ond May  20.  In  considering  the  data  of  Table  I  it  is  seen  that  more 
than  one-third  of  the  collections  were  made  in  April,  but  of  those 
species  collected  in  both  April  and  May,  and  in  collections  made 
in  May  alone,  the  development  of  the  root  fungus  was  usually  better 
in  the  later  collections. 

The  two  collections  of  Podophyllum  made  in  April  revealed  a 
late  state  in  the  fungus  infection  (figs.  42,  43;  pi.  7).  Most  of  the 
roots  possessed  an  endotroph  in  the  shape  of  a  small  branched,  phyeo- 
mycetoid  fungus,  mostly  in  the  inner  cortical  cells  near  the  endo- 
dermis.  The  cells  near  the  endodermis  showed  stages  of  disorganiza- 
tion and  digestion  of  the  fungus  with  the  appearance  of  starch 
grains.  Normal  cells  were  filled  with  starch  grains.  The  fungus 
occurred  as  far  back  as  2  cm.  from  the  root  tip.  Root  hairs  were 
present  in  both  collections. 

It  is  also  to  be  noticed  in  the  first  table  that  the  mycorrhiza  of 
the  ferns  and  herbaceous  plants  are  endotrophic  in  habit,  with  the 
exception  of  Sanguinaria,  Onoclea  and  one  collection  of  Pteris.  In 
examining  such  plants  in  the  field  it  is  often  difficult  to  determine 
whether  or  not  there  is  a  fungus  association  present,  and  it  is  usual- 
ly necessary  to  examine  the  roots  microscopically  before  one  can  be 
certain.  In  the  endotrophic  association  there  are  in  most  cases  a 
few  root  hairs  present  on  the  roots,  although  they  may  be  greatly 
twisted  and  distorted,  but  in  some,  as  in  the  case  of  Podophyllum 
discussed  previously,  the  root  hair  development  may  appear  to  be 
quite  normal.  The  roots  of  Caulophyllum  were  extremely  interest- 
ing, being  massed  into  a  great  tangle,  all  eight  to  ten  inches  long, 


MYCOREHIZA  IN  FOREST  PLANTS  49 

seldom  branched,  spirally  twisted,  and  of  the  same  diameter  through- 
out, except  for  a  slight  swelling  at  the  tip.  There  was  no  sign  of 
root  hair  formation.  On  examination  of  freehand  sections,  the 
root  tips  were  found  to  be  filled  with  a  large,  phycomycetoid  endo- 
troph.  The  hyphae  were  seen  to  enter  between  epidermal  cells,  the 
growth  being  both  intercellular,  and  intracellular. 

Of  the  ferns  possessing  mycorrhiza,  all  revealed  an  endotrophic 
fungus  except  Onoclea,  and  one  collection  of  Pteris.  The  ectotroph 
of  Onoclea  sensibilis  appeared  to  be  the  same  as  that  of  the  horn- 
beam and  oak.  The  ectotroph  of  Pteris,  however,  was  composed  of 
very  small,  branching  hyphae.  The  weft  was  of  considerable  thick- 
ness near  the  root  tip,  and  at  places  on  the  older  roots  (fig.  11; 
pi.  2).  One  collection  of  Pteris  possessed  an  enormous  endotroph 
forming  arbuscles  (fig.  10;  pi.  2),  in  addition  to  the  ectotroph. 
These  were  apparently  different  fungi.  The  latter  collection,  as 
can  be  noticed  in  the  table,  came  from  a  forest  soil  with  a  pH  value 
of  7.2,  whereas  the  former  came  from  a  soil  which  gave  a  reaction 
of  pH  6.4.  Such  results  are  not  in  accordance  with  what  some  of 
the  literature  on  this  phase  of  mycorrhiza  would  lead  one  to  expect. 
Melin  (12)  has  stated  that  mycorrhizal  fungi  thrive  best  in  a  soil 
of  pH  5.0  or  lower,  and  that  there  is  poor  development  in  neutral 
soil.  Knudson  (7)  in  studying  the  germination  of  orchid  seeds, 
found  that  best  growth  of  seedlings  was  obtained  in  inoculated 
cultures  where  the  pH  value  was  0.2  to  4.4.  The  controls,  or  un- 
inoculated  cultures,  remained  at  pH  5.7.  Knudson  is  of  the  opinion 
that  in  the  orchid,  at  least,  the  increase  in  the  hydrogen-ion  con- 
centration is  due  to  the  fungus.  The  two  orchids  in  which  mycor- 
rhiza were  found  in  this  investigation  were  in  acid  soil,  one  being 
in  a  soil  of  pH  6.8.  But  of  the  thirty-three  collections  including 
twenty  species  of  plants  listed  in  Table  I,  all  but  nine  were  in  a 
soil  of  pH  6.5  or  more,  ten  of  them  being  collected  in  soils  with  pH 
values  ranging  from  7.0  to  8.0. 

Of  those  species  collected  in  alkaline  soils  the  mycorrhizal  fungus 
was  endotrophic  in  habit  except  in  Ostrya  and  Pteris.  The  ecto- 
trophic  weft  found  in  all  plants  of  Ostrya  that  were  examined  was 
similar  to  the  weft  found  in  oak  and  cottonwood  (pi.  6).  The  weft, 
or  fungus  mantle,  was  composed  of  septate  hyphae,  and  in  several 
collections  masses  of  loose,  basidiomycete  mycelium  were  found  in 
the  soil  about  the  root.  No  clamp-connections  were  found  in  the 
hyphae  of  the  weft,  nor  in  those  collections  where  the  same  fungus 


50  IOWA  STUDIES  IN  NATURAL  HISTOEY 

was  endotrophie  as  well  as  eetotrophic.  Melin  (9)  reports  in  this 
type  of  fungus  the  existence  of  a  pseudoparenehymous  mass  of 
hyphas  within  the  cortical  cells,  and  believes  that  it  is  here  that 
infection  sets  in,  the  fungus  mantle  being  formed  later.  In  the 
hornbeam,  under  the  oil  immersion  lens,  I  observed  the  mass  of 
septate  haustoria  or  intercellular  hyphal  tips  about  the  epidermal 
cells  and  penetrating  between  the  cortical  cells,  but  I  saw  no  in- 
stance in  which  they  seemed  to  be  intracellular.  Five  of  the  young 
hornbeam  plants  examined  were  seedlings  of  the  first  year,  and  two 
were  in  their  second  year  of  growth.  It  should  be  noted  in  this 
connection  that  not  only  in  Ostrya,  but  in  Fraxinus,  and  in  one 
collection  of  Pteris,  the  well  developed  ectotroph  was  associated 
with  an  endotroph  believed  to  be  the  same  fungus. 

The  ectotroph  of  Populus  seems  to  be  the  same  fungus  as  that 
of  Ostrya.  The  cottonwood  plants  were  collected  in  the  sand  about 
fifteen  feet  from  the  water  line  of  the  lake,  where  the  pH  value  for 
all  collections  was  near  6.5.  In  one  collection  a  phycomycetoid 
endotroph  was  present  also  (figs.  35,  36;  pi.  6). 

The  data  of  Table  II  require  more  discussion.  It  should  be  noted 
that  the  collections  of  Ariscema  and  Cystopteris  are  the  only  col- 
lections definitely  corroborating  previous  evidence  on  mycorrhizal 
relationship  to  hydrogen-ion  concentration  as  given  by  other  work- 
ers. In  the  first  species  the  collection  which  revealed  an  abundant, 
phycomycetoid  endotroph  and  the  collection  which  proved  to  be 
negative,  were  made  in  the  same  woods,  the  former  in  late  May,  and 
the  latter  on  April  19.  The  hydrogen-ion  concentrations  of  the  two 
soils  were  pH  5.4  and  6.7  respectively.  The  endotroph  of  Ariscema 
(fig.  22;  pi.  4)  exhibited  numerous  arbuscle  formations  similar  to 
those  described  by  Demeter  (2)  and  Gallaud  (4).  Likewise,  in  the 
case  of  the  two  collections  of  Cystopteris,  one  possessed  a  mycor- 
rhizal endotroph,  and  was  collected  the  same  time  and  place  as  the 
positive  collection  of  Ariscema.  The  other,  which  was  negative,  was 
collected  with  the  negative  collection  of  Ariscema.  The  hydrogen- 
ion  concentrations  of  the  two  soils  were  pH  5.2  and  6.7,  being  prac- 
tically the  same  as  the  values  for  the  two  collections  of  Ariscema. 
It  should  be  noted  that  both  negative  collections  were  made  in  the 
middle  of  April,  the  positive  late  in  May,  and  that  in  the  discussion 
of  Table  I  it  was  emphasized  in  connection  with  Orchis  that  al- 
though over  one-third  of  the  collections  in  that  table  were  made 


MYCORRHIZA  IN  FOREST  PLANTS  51 

in  April,  there  was  in  most  eases  a  better  my corrhizal  development 
in  those  collections  made  in  May. 

The  third  collection  of  Osmunda,  and  the  second  collection  of 
Adiantum,  possessed  endotrophic  mycorrhiza  as  did  most  of  the 
ferns  listed  in  the  first  table.  In  the  first  collection  of  Adiantum 
an  ectotrophie  basidiomycete  fungus  (figs*  1,  2;  pi.  1)  formed  a 
mantle  of  considerable  thickness.  Thus  of  the  eight  collections  of 
ferns  in  which  mycorrhizal  fungi  were  found,  all  possessed  an  endo- 
trophic fungus  except  one  collection  of  Adiantum,  and  the  collection 
of  Onoclea.  The  two  examples  cited  are  in  agreement  with  the  find- 
ings of  others  as  to  the  occurrence  of  mycorrhiza,  but  it  will  be  noted 
that  in  the  case  of  Adiantum  the  positive  collection  possessing  an 
ectotrophie  fungus  was  from  a  neutral  soil,  and  the  positive  col- 
lection possessing  an  endotrophic  fungus  was  from  an  acid  soil* 
while  both  negative  collections  were  from  nearly  neutral  soils.  How- 
ever, the  two  positive  collections  were  made  in  the  spring,  and  the 
two  negative  in  October.  Also,  in  the  case  of  Osmunda,  the  negative 
collections  were  from  soils  of  pH  5.1  and  6.2,  one  being  made  in 
April  and  one  in  October,  while  the  positive  collection  was  from, 
a  soil  of  pH  6.8,  collected  in  October. 

The  vesicles  in  the  endotroph  of  Adiantum  (figs.  3,  5 ;  pi.  1 ;  and 
fig.  2;  pi.  8),  were  similar  to  those  described  by  West  (24)  for  the 
mycorrhiza  of  the  Marattiaceae,  and  by  Demeter  (2),  and  Magrou 
(8).  Terminal  and  intercalary  vesicles  were  observed,  both  occur- 
ring intracellularly  and  intercellularly.  There  were  no  root  hairs 
present,  and  the  roots  were  much  distorted,  with  short  thick  branch-, 
es,  the  tips  being  black.  In  examination  of  prepared  slides  the 
extent  of  cellular  disorganization  near  the  endodermis,  and  the, 
abundance  of  the  large,  branched,  elongate  hyphae  suggest  a  possible, 
case  of  true  parasitism  on  the  part  of  the  fungus.  Since,  in  external 
appearance  the  roots  exhibited  the  usual  mycorrhizal  characters, 
for  the  ferns,  it  seems  probable  that  the  mycorrhizal  endotroph  had 
overcome  the  capacity  of  the  roots  to  hold  the  fungus  in  check. 

The  ectotroph  of  the  bur-oak  (figs.  38,  39;  pi.  6)  appeared  iden- 
tical with  that  found  in  the  cottonwood  and  hornbeam,  forming  a 
pseudoparenchymous  layer  about  the  short,  thick,  lateral  roots. 
(See  fig.  46;  pi.  8).  The  external  characters  of  the  roots  and  the 
character  of  the  fungus  layer  forming  the  mantle  were  typical  of 
the  ectotrophie  mycorrhiza  of  common  forest  trees,  as  described  by 
Frank  (3)  and  others.    On  a  lateral  root,  0.12  mm.  in  diameter,  the. 


52  IOWA  STUDIES  IN  NATURAL  HISTORY 

thickness  of  the  fungus  weft  averaged  20  microns,  a  condition  found 
in  general  for  all  woodland  collections  of  Quercus.  Six  of  the  col- 
lections were  made  at  the  edge  of  a  bur-oak  forest,  some  of  the  seed- 
lings being  quite  in  the  open.  One  of  the  seedlings  examined  was 
in  the  first  year  of  growth,  three  were  in  the  second,  and  one  in  the 
third.  All  were  rooted  from  three  to  ten  inches  below  the  surface 
of  the  soil,  and  none  possessed  roots  with  root  hairs.  The  soil  was 
alkaline,  the  hydrogen-ion  concentrations  for  the  soil  solutions  rang- 
ing from  pH  7.5  to  8.1,  as  shown  in  the  table. 

One  collection  of  Quercus,  a  seedling  of  the  first  year,  growing 
in  the  sand  about  fifteen  feet  from  the  water  of  the  lake,  proved 
negative.  This  collection  was  made  at  the  same  time  as  that  of 
Populus  which  possessed  the  ectotrophic  fungus  and  the  plants  were 
only  a  few  feet  apart.  The  pH  value  of  the  soil  solution  of  the 
sandy  beach  was  6.6  for  both  collections.  In  the  oak  the  lateral 
roots  were  normal,  root  hairs  were  present  in  abundance,  but  dis- 
torted due  to  growth  in  the  sand. 

Table  III  requires  little  discussion,  as  negative  results  contribute 
no  conclusive  evidence,  especially  when  so  few  collections  of  in- 
dividual species  are  recorded.  Of  the  fifteen  species  in  which  myeor- 
rhiza  were  not  found  there  was  but  one  collection  each  of  all  but 
four.  On  comparing  the  notes  in  Tables  I  and  II  it  will  be  found 
that  of  the  thirteen  species  collected,  with  two  or  more  collections 
of  each,  approximately  all  but  one-third  gave  positive  results  for 
each  collection.  Thus  it  is  highly  probable  that  at  least  five  of  the 
fifteen  species  listed  in  Table  III  do  ordinarily  have  mycorrhiza. 
With  positive  results  in  Equisetum  arvense,  Smilacina  racemosa, 
Viola  sororia,  and  two  species  of  Galium,  mycorrhiza  would  be  ex- 
pected to  be  present  in  the  species  of  the  same  genera  listed  in  Table 
III.  With  so  much  evidence  in  the  literature  regarding  the  pres- 
ence of  a  fungus  in  the  orchids,  the  negative  results  in  the  case  of 
Cypripedium  were  surprising.  Root  hairs  were  present  in  both 
collections  of  Cypripedium.  One  collection  was  made  in  Iowa 
County,  growing  in  a  fairly  acid  soil  in  a  dense  woods,  and  flower- 
ing; while  the  other  was  a  lone  specimen  in  a  bur-oak  woods  of 
Dickinson  County,  where  the  soil  was  alkaline.  Likewise,  the  two 
collections  of  Smilacina  stellata  were  from  the  alkaline  soil  of 
Dickinson  County,  whereas  the  two  collections  of  S.  racemosa  giving 
positive  results  were  from  the  more  acid  soils  of  Johnson  County. 

Correlating  the  data  of  the  three  tables  in  regard  to  the  hydrogen- 


MYCORRHIZA  IN  FOREST  PLANTS       53 

ion  concentration  of  the  soil  solution  it  is  found  that  for  the  seventy 
collections  made,  fifty-one  were  from  soils  of  pH  6.5,  or  more,  the 
highest  pH  value  recorded  being  .8.2.  The  value  of  pH  6.5  is  taken 
as  an  arbitrary  value  below  which  conditions  are  in  general  more 
favorable  for  the  development  of  soil  and  root  fungi.  Melin  (12) 
has  investigated  the  influence  of  hydrogen-ion  concentration  of  soils 
and  culture  media  on  the  vigor  of  the  pine  and  fir  root-fungi.  He 
concludes  that  in  general  mycorrhizal  fungi  thrive  best  at  pH  5.0 
or  slightly  lower,  with  poor  development  at  pH  7.0 ;  and  that  Rhizoc- 
tonia  sylvestris  and  Mycelium  r.  atrovirens  thrive  equally  well  in 
neutral  and  acid  media,  the  latter  thriving  in  all  types  of  forest 
soil.  In  view  of  these  observations  it  seems  probable  that  the  value 
of  pH  6.5  chosen  above  is  too  high.  The  ectotrophic  fungus  found 
so  commonly  in  this  investigation  on  Ostrya  and  Quercus  (and  on 
one  collection  of  Populus  from  the  same  region),  is  believed  to  be 
a  Rhizoctonia,  and  all  except  the  collection  of  Populus  were  taken 
from  soils  with  pH  values  ranging  from  7.2  to  8.1. 

Of  the  fifty-one  collections  taken  from  soils  of  pH  6.5  or  of  a 
higher  pH  value,  thirty  (representing  seventeen  species)  possessed 
mycorrhiza-like  conditions.  Seventeen  (56  per  cent)  of  the  thirty 
were  from  soils  ranging  from  7.0  to  8.1  (representing  eight  species 
of  plants).  Of  the  remaining  nineteen  collections  of  pH  value  less 
than  6.5,  thirteen  (representing  the  same  number  of  species)  were 
positive.  Eight  of  these  (representing  eight  species)  were  from 
soils  ranging  from  pH  4.9  to  5.5.  These  numbers  substantiate  to 
some  extent  the  results  of  Melin  and  other  workers,  as  discussed 
previously,  in  that  approximately  70  per  cent  of  the  collections  with 
a  pH  value  below  6.5  were  positive,  indicating  that  an  acid  soil  is 
the  more  favorable  for  mycorrhiza ;  also  in  that  nearly  half  of  the 
collections  from  soils  of  pH  6.5  or  of  a  higher  pH  value  were  nega- 
tive. It  is  evident  that  approximately  77  per  cent  of  the  negative 
collections,  and  70  per  cent  of  all  positive  collections  were  from 
soils  of  pH  6.5  or  above,  but  these  figures  cannot  be  balanced  against 
the  preceding  figures,  for  more  than  70  per  cent  of  all  collections 
were  made  on  alkaline,  neutral,  or  slightly  acid  soils. 

Thus,  it  seems  evident  that  in  the  Iowa  forest  flora,  mycorrhiza 
or  mycorrhiza-like  fungi  are  of  common  occurrence,  and  are  wide- 
spread among  species  of  higher  plants,  in  acid,  neutral,  and  alkaline 
soils,  but  are  more  common  and  better  developed  in  soils  of  pH 
value  below  6.5.    Far-fetched  generalizations  should  not  be  drawn 


54  IOWA  STUDIES  IN  NATURAL  HISTORY 

from  too  little  evidence,  but  it  is  believed  that  the  evidence  cited 
in  the  above  discussion  concerning  mycorrhizal  development  and 
hydrogen-ion  concentration,  is  worthy  of  note  in  that  (1)  the  pH 
values  are  fairly  accurate;  (2)  the  species  of  plants  examined  are 
quite  representative  of  the  Iowa  forest  flora;  (3)  the  types  of  soils 
from  which  collections  were  made  are  also  representative  forest 
soils  of  Iowa;  and  (4)  collections  were  made  throughout  the  grow- 
ing season. 

SUMMARY  OF  RESULTS 

(1)  The  seventy  individual  plants  collected  and  examined  from 
typical  forested  areas  of  Johnson,  Iowa,  and  Dickinson  counties, 
represented  twenty-one  families,  thirty-four  genera,  and  forty 
species. 

(2)  Sixteen  of  the  collections  were  of  Pteridophytes,  represent- 
ing four  families,  eight  genera,  and  nine  species.  All  other  collec- 
tions were  of  higher  plants. 

(3)  Of  the  total  number  of  collections,  forty-three,  representing 
sixteen  families,  twenty-four  genera,  and  twenty-five  species,  dis- 
closed association  with  a  mycorrhiza-like  fungus. 

(4)  Of  the  forty  species  examined,  twenty  showed  a  root-fungus 
association  in  every  plant  examined,  five  in  some  cases  but  not  in 
others,  and  fifteen  showed  no  trace  of  mycorrhizal  fungi. 

(5)  Of  the  forty-three  positive  collections  twenty-four  possessed 
mycorrhizal  endotrophs,  fifteen  mycorrhizal  ectotrophs,  and  four 
had  both  endotrophic  and  ectotrophic  root-fungi. 

(6)  In  the  collection  of  Fraxinus,  one  collection  of  Ostrya  and 
one  collection  of  Pteris,  the  endotroph  and  ectotroph  are  in  each 
case  believed  to  be  the  same  fungus. 

(7)  Two  of  the  twenty-four  collections  with  endotrophic  fungi 
showed  vesicle  formations,  one  being  of  Adiantum  pedatum,  and 
the  other  of  Melilotus  alba. 

(8)  The  following  species  with  endotrophs  showed  arbuscle  for- 
mations: Ariscema  triphyllum,  Botrychium  virginianum,  Erythro- 
nium  albidum,  Galium  aparine,  G.  triflorum,  Pteris  aquilina,  Smila- 
cina  racemosa,  and  Uvularia  perfoliata. 

(9)  The  ectotroph  of  Ostrya,  Quercus,  Populus,  and  Onoclea* 
is  believed  to  be  the  same  fungus,  probably  a  Rhizoctonia.  Ostrya 
virginiana  and  Quercus  macrocarpa  are  provided  constantly  with 
a  fungus  ectotrophic  in  character. 


MYCORRHIZA  IN  FOREST  PLANTS       55 

(10)  In  ectotrophie  forms  intercellular  hyphae  were  observed 
about  the  epidermal  cells,  and  between  cortical  cells,  but  no  intra- 
cellular, pseudo-parenchymous  masses  were  found. 

(11)  In  endotrophic  forms  both  intercellular  and  intracellular 
hyphae  were  observed,  the  hyphae  passing  freely  from  one  cell  to 
another,  but  most  growth  being  intracellular. 

(12)  In  endotrophic  forms  hyphae  were  observed  entering  be- 
tween epidermal  cells  and  penetrating  the  walls  of  the  cortical  cells, 

(13)  The  usual  stages  of  infection  and  disorganization  as  re- 
ported by  other  workers  were  observed  in  the  endotrophic  forms. 

(14)  Fungus  hyphae  were  found  in  epidermal  cells  in  several 
cases  but  the  means  of  infection  could  not  be  determined.  They 
were  observed  to  extend  from  epidermal  cells  into  cortical  cells  in 
Smilacina  racemosa.  They  were  never  found  entering  the  epidermal 
cells  directly  as  reported  by  Melin  (9)  and  West  (24). 

(15)  The  endotroph  of  Orchis,  and  of  Corallorrhiza  is  believed 
to  be  the  typical  orchid  endotroph. 

(16)  Numerous  roots  of  two  collections  of  Cypripedium  were 
examined  and  no  trace  of  a  fungus  was  found.  Both  plants  were 
thriving,  one  being  in  flower. 

(17)  The  pH  value  of  the  soil  solutions  of  plants  examined 
ranged  from  4.9  to  8.2.  The  soils  were  typical  forest  soils  of  John- 
son, Iowa,  and  Dickinson  counties. 

(18)  Fifty-one  of  the  seventy  collections  were  from  soils  of  pH 
6.5  or  more.  Thus  more  than  70  per  cent  of  all  collections  were 
from  alkaline,  neutral,  or  slightly  acid  soil. 

(19)  Of  the  forty-three  positive  collections  and  twenty-seven 
negative  collections,  approximately  70  per  cent  of  the  former  and 
77  per  cent  of  the  latter  were  from  soils  of  pH  6.5  or  more. 

(20)  Of  the  nineteen  collections  from  soils  below  6.5  in  pH 
value,  70  per  cent  were  positive. 

CONCLUSIONS 

(1)  Mycorrhiza-like  fungi  are  of  common  occurrence  in  the 
Iowa  forest  flora,  and  are  associated  with  higher  plants  of  wide 
family  relationship. 

(2)  In  general,  the  endotrophic  forms  are  more  common  than 
the  ectotrophie  in  ferns  and  herbaceous  higher  plants. 

(3)  In   ectotrophie   forms   haustoria    or   intercellular   hyphal 


56  IOWA  STUDIES  IN  NATURAL  HISTOEY 

branches  penetrate  between  the  epidermal  cells,  and  in  some  cases 
penetrate  between  the  cortical  cells  of  the  root. 

(4)  A  fungus  may  be  either  ectotrophic,  or  endotrophic,  or  both 
in  habit,  in  its  association  with  the  root  of  a  higher  plant. 

(5)  Mycorrhiza-like  fungi  occur  in  Iowa,  associated  with  higher 
plants  in  acid,  neutral,  and  alkaline  soils,  but  they  are  more  common 
and  develop  better  in  soils  with  a  pH  value  below  6.5. 

These  studies  were  carried  out  under  the  direction  of  Professor 
G.  W.  Martin,  to  whom  I  am  indebted  for  helpful  suggestions  and 
criticisms,  and  for  the  abundant  collections  of  Corallorrhiza  odon- 
torhiza  which  was  the  incentive  for  this  particular  study  at  the 
State  University  of  Iowa. 


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58  IOWA  STUDIES  IN  NATURAL  HISTORY 

19#     The  nutrition  of  mycorrhiza  plants;    Calluna  vulgaris.     Brit. 

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Marattiaceae.    Ann.  Bot.  31:  77-99.     1917. 


PLATES 

All  drawings  were  made  with  the  aid  of  camera  lucida,  at  a  magnification 
of  630  diameters  unless  otherwise  stated,  and  reduced  one-half  in  reproduction. 

Abbreviations  used  in  labeling 
ep — epidermis  st — stele 

en — endodermis  en — cell  nucleus 

ec — epidermal  cell  re — root  cap 

co — cortical  cell  fw — fungus  weft 

ctx — cortex 


PLATE  I 

Fig.  1.  Longitudinal  section  of  lateral  root  of  Adiantum  pedatum  showing 
pseudoparenchymous  layer  formed  by  ectotrophic  hyph.se. 

Fig.  2.  Epidermal  cells  in  longitudinal  section  near  tip  of  root  of  same 
plant.  The  septate  hyphse  of  the  fungus  ectotroph  show  a  clamp 
connection. 

Fig.     3.     Longitudinal  section  of  root  of  another  plant  of  same  species  show- 
ing  intercalary,   intracellular   vesicle   about   8   mm.   from  tip   of 
root. 
Longitudinal  section  of  same  root  showing  hyphal  branch  entering 

the  root  between  epidermal  cells. 
Cortical  cells  of  same  root  in  longitudinal  section  showing  hyphal 
growth  from  one  cell  to  another,  but  most  growth  being  intra- 
cellular.    Also  a  terminal,  intracellular  vesicle  in  second  layer  of 
cortical  cells  beneath  the  epidermis,  about  1  cm.  from  root  tip. 
Longitudinal   section  of   same   root   showing  septate  hyphae   of  an 
endotrophic  fungus  associated  with  the  one  forming  vesicles,  but 
probably  another  fungus. 
Longitudinal   section   of   root   of  Botrychium  virginianum   showing 
disorganizing  hyphae  of  fungus  endotroph,  and  unorganized  cell 
contents,  in  third  and  fourth  layer  of  cortical  cells  beneath  the 
epidermis,  about  5  mm.  from  tip  of  root. 

Fig.  8.  Root  of  Equisetum  arvense  in  longitudinal  section  showing  hyphal 
characters  of  fungus  in  middle  cortical  cells. 


Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

PLATE  I 


PLATE  II 

Fig.  9.  Longitudinal  section  of  same  root  of  Equisetum  arvense  showing1 
external  epidermal  surface  and  cortical  cells  beneath,  with  fungus 
hyphae  entering  between  epidermal  cells.  The  flattened  tips  of 
the  intercellular  liyphal  branches  are  pressed  against  the  walls  of 
the  first  layer  of  cortical  cells  beneath. 

Fig.  10.  Root  of  Pteris  aquilina  in  longitudinal  section  showing  arbuscle 
formations  in  large  cortical  cells,  and  hyphae  of  an  ectotrophic 
fungus  of  different  character;   ep,  epidermis,  and  en,  endodermis. 

Fig.  11.  Longitudinal  section  of  another  part  of  same  root  showing  hyphae 
of  fungus  ectotroph  of  fig.  10  entering  between  two  epidermal 
cells,  ec,  with  their  intercellular  tips  pressed  against  lower  surface 
of  large  cortical  cells,  cc.  Oil  immersion;  original  magnification 
approximately  x  1100. 

Fig.  12.  Longitudinal  section  of  root  of  Onoclea  sensibiJis  showing  thick  weft 
of  ectotrophic  hyphae  forming  pseudoparenchymous  outer  layer, 
and  the  haustoria  penetrating  between  epidermal  cells. 

Fig.  13.  Diagram  of  portion  of  median  longitudinal  section  of  same  root  tip 
showing  relative  thickness  of  fungus  weft  to  other  parts  of  root. 
Note  the  haustoria  between  the  epidermal  cells;  en,  endodermis, 
and  st,  stele. 


PLATE  II 


i-i\.'--i  >  i  ill  j- 


cc 


PLATE  III 

Fig.  14.  Corallorrhisa  odontorhisa.  Longitudinal  section  of  slender,  root-like, 
subterranean  part  showing  hyphae  of  typical  orchid  endotroph  in 
cortical  cells  immediately  beneath  the  epidermis,  ep,  1  mm.  from 
tip  of  i '  root ? ' ;   en,  cell  nucleus. 

Fig.  15.  Cross  section  of  similar  part  ("root")  of  same  plant  showing  dis- 
organization of  fungus  hyphse,  in  inner  cortical  cells  4  mm.  from 
the  tip.  Note  enlargement  of  cell  nucleus  en,  on  infection  of  cell 
by  the  fungus. 

Fig.  16.  Cross  section  of  short,  thick,  tuberous,  subterranean  part  of  same 
plant  showing*  fungus  hypliae  in  epidermal  cells. 

Fig.  17.  Longitudinal  section  of  similar  part  showing  stages  of  mycelial  dis- 
organization in  inner  cortical  cells. 


PLATE  III 


PLATE  IV 

Fig.  18.  Orchis  spectabilis.  Cross  section  of  root  showing  typical  orchid 
fungus  in  cortical  cells,  and  enlargement  of  cell  nucleus  en,  on 
infection  of  cell  by  fungus. 

Fig.  19.  Longitudinal  section  of  root  of  Caulophyllum  thalietroides  showing 
phycomycetoid  endotroph  with  branching  hyphae,  in  inner  cortical 
cells.  The  normal  cell  on  left  shows  starch  grains,  and  cell  above 
shows  disorganization  of  hyphae;   en,  cell  nucleus. 

Fig.  20.  Cross  section  of  another  root  of  same  plant  showing  disorganization 
of  hyphae  in  an  inner  cortical  cell.  The  cells  are  of  the  third  and 
fourth  row  beneath  the  epidermis  about  4  mm.  from  root  tip; 
en,  cell  nucleus. 

Fig.  21.  Erythronium  albidum.  Cross  section  of  root  showing  hyphae  of  the 
endotroph  in  second  and  third  layers  of  cortical  cells  beneath 
epidermis. 

Fig.  22.  Ariscema  triphyllum.  Longitudinal  section  of  root  showing  endo- 
troph forming  arbuscles  in  third  layer  of  cortical  cells  beneath 
epidermis  about  2  cm.  from  root  tip;   en,  cell  nucleus. 


PLATE  IV 


PLATE  V 

Fig.  23.  Erytlironium  albidum.  Longitudinal  section  of  root  showing  branch- 
ing hypha?  of  fungus  endotroph  and  formation  of  arbuscles  in 
second  and  third  layers  of  cortical  cells  3  mm.  from  tip  of  root. 

Fig.  24'.  Longitudinal  section  of  root  of  Hepatica  acutiloba  showing  in  cor- 
tical cells  the  hyphse  of  the  endotroph  3  mm.  from  tip  of  root. 

Fig.  25.  Cross  section  of  root  of  same  plant  2  mm.  from  tip  showing  fungus, 
hypha?  and  hyphse  being  digested;  en,  endodermis;  st,  stele;  and  ep, 
epidermis. 

Fig.  26.  Melilotus  alba.  Cross  section  of  root  showing  disorganizing  phyco- 
mycetoid  hyphge  in  cortical  cells. 

Fig.  27.  Longitudinal  section  of  root  of  another  plant  of  same  species,  through 
older  part  of  root  above  bacterial  nodules,  showing  terminal  inter- 
cellular vesicles  between  cortical  cells. 

Fig.  28.  Longitudinal  section  of  same  root  showing  intracellular  and  inter- 
cellular hyphae  near  endodermis  en\   ep,  epidermis. 


PLATE  V 


PLATE  VI 

Fig.  29.  Ostrya  virginiana.  Cross  section  of  short,  thick,  lateral  root,  showing- 
outer  pseudoparenchymous  layer  formed  by  the  weft  of  fungus 
hyphae. 
Fig.  30.  Longitudinal  section  of  root  of  same  plant  showing  on  external 
epidermal  surface  the  type  of  fungus  hyphae  which  forms  the  weft 
in  fig.  29. 

External  surface  view  of  hyphae  forming  weft  on  roots  of  Ostrya. 

Cells  in  longitudinal  section  of  Ostrya  root  showing  hyphae  of  ecto- 
troph  and  haustoria  between  epidermal  cells.  Oil  immersion; 
original  magnification  approximately  x  1400. 

Hyphal  character  of  fungus  forming  weft  in  fig.  32. 

Longitudinal  section  of  Ostrya  root  some  distance  from  tip  show- 
ing same  fungus  as  an  ectotroph  and  an  endotroph ;  ep,  epidermis. 

Populus  deltoides.  Cross  section  of  short  lateral  root  showing  pseudo- 
parenchymous layer  of  hyphae  of  fungus  ectctroph;  en,  endodermis. 

Longitudinal  section  of  root  of  another  ccttonwood  seedling  show- 
ing endotroph  in  cells  next  to  endodermis  en.  This  condition 
present  mostly  some  distance  from  rod  tip.  The  ectotroph  of 
fig.  35  was  also  present  on  this  rod  at  tip. 
Fig.  37.  Fraxinus  pennsylvaniea  var.  lanceolata.  Longitudinal  section  of 
lateral  root  showing  endotrophic  hyphae  in  cortical  cells  near  root 
tip. 
Fig.  38.  Longitudinal  section  of  root  tip  of  Que  reus  maeroearpa  showing 
ectotrophic  fungus  hyphae.  Note  resemblance  to  same  condition 
in  Ostrya    (fig.  29),  Populus   (fig.   35),  and  Onoclea    (figs.  12  and 

13). 
Fig.  39.  Diagram  of  median  longitudinal  section  of  same  root  tip  to  illustrate 
relative  thickness  of  fungus  weft  to  ether  parts  of  root.  Root 
0.12  mm.  in  diameter;  average  thickness  of  fungus  weft  20  mi- 
crons; st,  stele;  etx,  cortex;  and  fw,  fungus  weft.  (Outlined  with 
camera   lucida,  l.p. — original   magnification   approximately  x   125.) 


Fig. 

31. 

Fig. 

32, 

Fig. 

33. 

Fig. 

34. 

Fig. 

35. 

Fig. 

36. 

PLATE  VI 


'^£5j 


PLATE  VII 

Fig.  40.  Uvularia  perfoliata.  Middle  cortical  cells  near  root  tip  in  longitu- 
dinal section  showing  hyphal  characters  of  endotroph  with  several 
arbuseles;   en,  cell  nucleus. 

Fig.  41.  Smiladna  raeemosa.  Longitudinal  section  showing  hyphae  forming 
arbuseles  in  inner  cortical  cells  about  1  cm.  from  root  tip.  Hyphae 
present  in  epidermal  cell  and  hyphal  branches  have  entered  two 
cortical  cells  within.  External  hyphae  of  same  character  are  pressed 
against  the  epidermal  cells,  ep.  Root  hairs  were  present  on  this 
root;   rh,  base  of  root  hair;  en,  cell  nucleus. 

Fig.  42.  Podophyllum  peltatum.  Semi-diagrammatic  drawing  of  cross  section 
of  root  about  1  cm.  from  tip  with  shaded  cells  to  show  region 
and  relative  abundance  of  fungus  endotroph.  (Outlined  with 
camera  lucida  l.p.     Original  magnification  approximately  x  125.) 

Fig.  4.3.  Longitudinal  section  of  another  root  of  same  plant  showing  hyphae 
and  digestion  of  hyphae  in  cortical  cells  1  to  2  cm.  from  root  tip. 
Note  starch  grains  in  normal  cell  below,  and  in  cells  showing 
hyphal  digestion;   en,  cell  nucleus. 


PLATE  VII 


OF 


PLATE  VIII 

Fig.  44.  Smilacina  racemosa;  photomicrograph  of  longitudinal  section  show- 
ing arbuscle  formation  in  inner  cortical  cells  about  1  cm.  from 
tip  of  root.      (See  pi.  7,  fig.  41). 

Fig.  45.  Adiantum  pedatum;  photomicrograph  of  longitudinal  section  show- 
ing vesicle  formation  by  fungus  endotroph  about  1  cm.  from  tip 
of  root.      (See  pi.   1). 

Fig.  46.  Quercus  macrocarpa ;  photomicrograph  of  cross  section  of  short 
lateral  root  showing  weft  of  ectotrophic  fungus  hvpha?  forming 
a  pseudoparenchymous-like  layer.      (See  pi.  6,  figs.  38  and  89). 


PLATE  VIII 


I  V 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  11 

METHODS  OF  MECHANICAL  ANALYSIS 
OF  SEDIMENTS 

by 
Chester  K.  Wentworth 


PUBLISHED  BY  THE  UNIVERSITY  OF  IOWA,  IOWA  CITY,  IOWA 


METHODS  OF  MECHANICAL  ANALYSIS 
OF  SEDIMENTS 

INTRODUCTION 

Purpose  op  Mechanical  Analysis 
The  mechanical  analysis  of  a  sediment  or  of  any  detrital  material 
may  serve  a  number  of  useful  ends.  The  most  obvious  result  of  such 
analysis  is  the  determination  of  the  several  sizes  of  particles  which 
are  present,  and  from  these  data  the  average  size  and  the  range  of 
coarseness  are  at  once  apparent.  A  complete  mechanical  analysis, 
however,  involves  not  only  the  determination  of  the  sizes  of  particles 
which  are  present  but  also  the  proportions  by  weight  or  volume  in 
which  the  several  grades  occur.  And  finally,  as  the  third  aim  of 
mechanical  analysis,  there  result  the  several  grades  of  material, 
each  separated  from  coarser  and  finer  material  and  best  adapted 
for  study  and  preservation. 

Knowledge  of  the  sizes  of  particles  which  are  present  in  a  given 
sediment  or  artificial  material  is  valuable  in  a  number  of  ways.  In 
the  case  of  a  natural  sediment  it  may  determine  the  name  by  which 
the  geologist  designates  the  material.1  In  cases  where  only  rough 
conf ormability  to  specifications  is  required  the  knowledge  of  grades 
present  in  part  determine  suitability  of  the  material  for  various 
technical  uses  such  as  the  value  of  gravel  for  road  metal,  sand  for 
glass  manufacture,  or  the  finer  natural  abrasive  materials  for  their 
several  uses.  A  determination  of  the  several  grades  present  is  a 
means  of  checking  the  performance  of  crushers  and  separators  used 
in  various  metallurgical  and  other  commercial  mineral  operations 
and  the  suitability  of  the  materials  so  prepared  for  the  next  stage 
in  the  process. 

Commonly  the  proportions  of  the  several  grades  are  determined 
and  these  additional  data  serve  much  more  refined  purposes.  Thus 
the  geologist  is  enabled  in  many  instances  to  deduce  the  mode  of 
origin  and  the  agent  of  deposition  from  a  series  of  mechanical 
analyses  of  a  certain  type  of  sediment  and  in  cases  where  this  is  not 
possible  the  data  thus  derived  still  serve  in  a  valuable  supplementary 

iWentworth,  O.  K.,  A  Scale  of  Grade  and  Class  Terms  for  Clastic  Sedi- 
ments, Journal  of  Geology,  Vol.  XXX,  pp.  377-392,  1922. 

3 


4  IOWA  STUDIES  IN  NATUEAL  HISTORY 

way.2  In  other  cases  mechanical  composition  may  serve  as  a  means 
of  correlating  detrital  formations  in  which  fossils  are  missing  or 
rare.3  An,  increasing  use  is  being  made  of  mechanical  analysis  as  a 
criterion  of  suitability  of  sediments  for  various  commercial  and 
engineering  operations.  Mechanical  composition  largely  determines 
the  value  of  materials  used  for  filtering  on  a  large  scale,  for  the  con- 
struction of  earthwork  dams  and,  to  a  lesser  but  still  important  ex- 
tent, of  materials  used  in  concrete  construction  and  of  molding 
sand.4  Likewise  an  increasing  attention  is  being  paid  to  mechanical 
composition  as  an  important  characteristic  in  writing  standard 
specifications  for  both  natural  and  artificial  materials  furnished  on 
contract. 

The  value  of  mechanical  separation  into  grades  can  hardly  be 
overestimated  either  for  critical  study  or  for  display  and  preserva- 
tion. To  the  student  investigating  the  petrology  or  mineralogy  of 
sediments,  well  cleaned  and  graded  materials  are  studied  with  an 
interest  and  an  economy  of  time  which  is  impossible  with  the  natural 
material.  For  example,  in  the  determination  of  minerals  it  is  found 
that  the  bulk  of  the  minerals  of  a  certain  sort  or  present  in  a  certain 
form  are  found  in  a  few  grades  only.  The  specialities  in  the  several 
grades  may  thus  be  dealt  with  in  the  place  where  they  are  most  im- 
portant and  where  their  relations  are  most  clearly  seen.  There  is 
an  economy  of  attention  and  a  proper  perspective  and  basis  for 
comparison  when  one  is  working  with  materials  of  similar  sizes 
that  is  lacking  when  working  with  unsorted  materials.  This  princi- 
ple governs  the  plan,  of  work  in  various  industrial  operations  and 
explains  the  difficulty  one  experiences  in  turning  suddenly  from 
very  coarse  to  very  fine  work  of  any  sort,  The  desirability  of  grad- 
ing materials  by  size  has  likewise  been  recognized  by  biologists  in 
studying  small  shells  and  similar  organic  objects. 

In  similar  fashion  the  display  of  sediments  or  other  such  mater- 
ials is  much  more  effective  after  grading  and  especially  if  the  several 
grades  present  are  displayed  in  proper  order  and  proportion  so  as 
to  give  a  vivid  notion  of  the  composition  of  the  natural  material. 


2  Dake,  C.  L.,  Missouri  School  of  Mines,  Bulletin,  Vol.  6,  No.  1,  p.  152,  et  seq., 
1921. 

s  Trowbridge,  A.  C,  and  Mortimore,  M.  E.y  Correlation  of  Oil  Sands  by  Sedi- 
mentary Analysis,  Economic  Geology,  Vol.  XX,  pp.  409-423,  1925. 

4  Littlefield,  Max,  Natural-bonded  Molding  Sand  Resources  of  Illinois,  Bull. 
Ills.  Geol.  Surv.,  No.  50,  1925. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  5 

The  Methods  in  Use 
Two  principal  methods  of  mechanical  analysis  are  in  common  use, 
screening  and  elutriation.  Under  elutriation  is  included  the  method 
of  settling  in  still  water,  though  some  writers  restrict  the  term  to 
the  rising  current  process  of  hydraulic  classification.5  A  third 
method — that  of  counting — with  several  variations,  completes  the 
list  of  methods  of  mechanical  analysis.  It  is  unfortunate  that  a 
single  rapid,  accurate  and  convenient  method  is  not  available  for 
the  mechanical  analysis  of  materials  of  all  the  degrees  of  coarseness 
which  are  common  in  natural  sediments.  Many  of  the  natural  sedi- 
ments are  of  aqueous  origin.  Such  sorting  as  these  exhibit  is  the 
result  of  more  or  less  perfect  hydraulic  classification  in  which  dens- 
ity, size,  shape  and  surface  texture  are  factors.  Because  of  this 
fact  it  has  been  pointed  out  that  analysis  by  elutriation  is  the  only 
satisfactory  method  of  securing  a  separation  which  depends  on  these 
same  factors  and  thus  approaches  closely  the  conditions  under 
which  the  sediment  was  deposited.  For  the  finer  sediments  the 
method  of  elutriation  in  one  form  or  another  is  admirable,  but  prac- 
tical difficulties  arise  in  applying  it  to  materials  coarser  than  the 
sand  grades.6  For  example,  the  settling  velocity  in  water  for  a 
quartz  pebble  5  cm.  in  diameter  is  about  5  meters  per  second.  The 
separation  of  materials  settling  at  rates  of  5  meters  per  second  in 
still  water  would  involve  prohibitive  quantities  of  water  and  sizes 
of  containers.  Likewise  the  rising  current  separation  of  such  grades 
is  impracticable.  In  a  tube  of  30  centimeters  diameter  a  velocity  of 
5  meters  per  second  will  discharge  approximately  5700  gallons  of 
water  per  minute.  It  is  apparent  that  some  other  method  for  the 
separation  of  the  coarser  grades  must  be  adopted.  The  use  of  sieves 
has  been  the  most  common  expedient.  Because  of  the  cheapness  and 
convenience  of  manufacture  in  a  wide  range  of  size  of  opening, 
woven  wdre  sieves  with  square  openings  are  the  most  practical.  In 
using  these  the  constituent  particles  are  classified  by  cross-sectional 
size  only ;  the  density  does  not  enter  as  a  factor  in  separations  and 
the  shape  only  as  it  affects  the  size  of  the  minimum  square  through 
which  the  rock  fragments  will  pass.  Thus  in  the  same  grade  are 
found  great  variation  in  density,  in  volume,  and  in  shape  and  the 
grade  may  consist  of  particles  which  will  not  exhibit  similar  be- 
havior in  streams  or  on  beaches  under  natural  conditions.     It  ap- 

s  Webster 's  International  Dictionary. 

6  Holmes,  A.,  Petrographic  Methods  and  Calculations,  p.  204,  London,  1921. 


6  IOWA  STUDIES  IN  NATURAL  HISTORY 

pears  to  the  writer  that  a  separation  on  the  basis  of  weight  of  the 
individual  particles  would  come  somewhat  closer  to  the  natural 
hydraulic  classification  and  he  has  used  this  method  of  grading  in 
connection  with  experiments  in  pebble  abrasion  but  so  far  as  is 
known  this  method  has  not  been  used  for  analysis  and  automatic 
methods  for  such  weight  separation  have  Dot  been  devised.  In 
spite  of  its  undesirable  features  the  method  of  sifting  in  woven  wire 
sieves,  by  virtue  of  its  convenience,  speed  and  relative  accuracy,  has 
come  to  be  the  standard  method  of  analysis  for  the  sands  and  coarser 
materials.  For  materials  finer  than  about  1/4  mm.  diameter  sieves 
are  less  satisfactory  because  of  the  tendency  of  the  finer  materials 
to  form  aggregates  and  to  lodge  in  the  sieve  openings.  "Wire  cloth 
has  been  woven  with  openings  somewhat  smaller  than  1/20  mm. 
but  the  finest  mesh  which  proves  practicable  in  the  grade  scale  ad- 
vocated by  the  writer  is  that  with  1/16  mm.  openings.  This  is  the 
lower  limit  of  the  method  of  sifting  and  for  finer  grades  elutriation, 
or  microscopic  counting  must  be  used.7  The  practical  upper  limit  of 
elutriation  may  be  set  at  one  millimeter.  Sediments  containing 
grades  from  one  millimeter  downward  may  be  handled  wholly  by 
elutriation ;  those  of  coarseness  ranging  from  1/16  mm.  upward  may 
be  handled  wholly  by  the  method  of  sifting.  It  is  apparent  that 
many  sediments  cannot  be  analysed  completely  by  either  method 
alone.  The  need  for  a  change  from  one  method  to  another  in  the 
course  of  the  analysis  of  these  sediments  is  perhaps  the  most  trouble- 
some element  in  the  whole  field  of  mechanical  analysis.  If  the  sedi- 
ment in,  question  is  composed  wholly  of  particles  of  the  same  density 
and  shape  the  problem  of  connecting  the  hydraulic  grade  scale  with 
the  cross-section  grade  scale  at  the  point  of  change  involves  accurate 
determination  of  the  hydraulic  values  of  the  particles  at  the  lower 
limit  of  the  smallest  sieve  grade.  If  it  is  desired  to  use  a  uniform 
notation  throughout  the  analysis  it  is  further  necessary  to  determine 
either  (1)  hydraulic  values  of  the  several  critical  sieve  sizes  above 
the  point  of  change  in  case  a  hydraulic  notation  is  to  be  used,  or  (2) 
the  cross-section  values  of  the  several  critical  hydraulic  values  in 
case  the  size  notation  is  preferred.  When  the  sediment  which  is  to 
be  analysed  contains  particles  of  various  densities  and  shapes,  the 
problem  becomes  not  only  much  more  complicated  but  is  not  capable 
of  exact  solution  and  the  two  types  of  grade  scale  must  be  joined 
by  compromise,  giving  the  larger  weight  to  the  shapes  and  densities 


7  Holmes,  A.,  Op.  tit.,  p.  204. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  7 

which  are  present  in  the  greatest  abundance.  Inadequate  appre- 
ciation of  the  nature  of  the  problem  on  the  part  of  students  of 
sediments  in  the  past  and  the  great  difficulty  of  reaching  even  an 
approximate  solution  under  standardized  conditions  has  led  to  much 
confusion  in  this  field  and  to  the  publication  of  many  different  com- 
binations of  grade  scales  and  to  great  diversity  of  assumptions  or 
determined  values  in  connecting  the  hydraulic  and  cross-section 
scales. 

This  situation  seems  to  have  been  the  principal  factor  in  the  de- 
cision of  certain  investigators,  notably  Udden,8  to  extend  the  sieve 
scale  downward  by  microscopic  counting.  This  method,  though  to 
a  less  degree  than  that  of  elutriation,  differs  from  the  sieve  method 
and  must  likewise  result  in  certain  discontinuity  at  the  point  of 
change  to  it  from  the  sieve  method.  The  method  of  counting, 
megascopic  and  microscopic,  is  applicable  to  the  whole  grade  range 
of  natural  sediments  and  is  undoubtedly  in  the  case  of  a  single 
critical  sample  the  best  method  of  making  an  accurate  mechanical 
analysis  now  available,  since  by  identifying  the  various  constituents 
the  density  factors  may  be  taken  into  account  and  the  resulting 
analysis  suffers  from  no  very  serious  discontinuity  if  care  is  taken 
to  use  comparable  methods  in  the  megascopic  and  microscopic  por- 
tions. Until  more  exhaustive  investigations  have  been  made  of  the 
effect  of  shape  on  rates  of  settling,  this  factor  introduces  unknown 
errors  in  the  recognition  of  the  natural  hydraulic  grades  by  the 
method  of  counting.  Furthermore,  counting  is  at  best  a  very  labor- 
ious procedure  and  is  therefore  hardly  applicable  to  large  numbers 
of  samples.  At  the  present  stage  of  interpretation  of  mechanical 
analysis  it  appears  to  be  more  profitable  to  examine  larger  numbers 
of  samples  with  considerably  less  theoretical  accuracy  by  some 
reasonably  expeditious  method. 

Scope  of  Present  Paper 
In  the  early  stages  of  any  sort  of  investigation  great  diversity  of 
methods  results  from  the  more  or  less  independent  work  of  different 
pioneer  students.  This  is  a  most  desirable  condition  for  it  results  in 
the  testing  of  many  different  types  of  procedure  and  in  the  explor- 
ation of  the  field  of  available  technique.  In  later  stages,  however, 
the  need  of  comparing  results  attained  by  different  workers  makes 


s  Udden,  J.  A.,  Mechanical  Composition  of  Clastic  Sediments,  Bull.  Geol.  Soe. 
Amer.,  Vol.  25,  pp.  655-744,  1914. 


8  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

some  degree  of  standardization  imperative.  The  great  diversity  of 
methods  used  by  pioneer  workers  is  the  result  in  large  part  of  ignor- 
ance of  methods  used  by  others  and  of  the  consequent  independent 
devising  of  methods. 

The  purpose  of  the  present  paper  is  to  bring  together  in  one  place 
descriptions  of  some  of  the  more  important  methods  of  mechanical 
analysis  where  they  may  guide  students  of  sediments  and  sedimenta- 
tion and  help  to  eliminate  some  of  the  existing  confusion.  It  is  not 
to  be  expected  that  any  one  method  will  be  used  to  the  entire  ex- 
clusion of  others ;  this  would  be  an  admission  that  the  study  of  sedi- 
ments is  stagnant  or  at  the  limit  of  growth.  But  on  the  other  hand, 
the  elimination  of  the  more  or  less  accidental  differences  of  graphic 
plotting  from  right  to  left  by  some  and  from  left  to  right  by  others, 
and  the  adoption  of  some  equal  ratio  geometrical  grade  scale  will 
be  conceded  by  all  as  appropriate  bases  for  standardization.  In  en- 
couraging the  adoption  of  the  preferred  methods  the  author  has 
considered  it  wise  to  go  into  considerable  detail  in  the  description 
of  the  various  methods  and  apparatus,  and  to  supplement  the  de- 
scriptions with  diagrammatic  illustrations  and  tabular  statements 
of  procedure. 

In  its  inception  the  present  paper  was  planned  as  a  joint  paper 
by  the  writer  and  his  colleague,  Max  S.  Littlefield;  the  latter  to 
prepare  the  part  relating  to  elutriation,  deflocculation  and  other 
methods  dealing  with  the  finer  sediments.  As  work  progressed  it 
became  apparent  that  the  technique  in  this  field  was  so  much  less 
well  elaborated  and,  indeed,  the  purpose  and  value  of  mechanical 
analyses  of  clay  grades  so  much  in  question  that  it  was  best  to  com- 
plete the  present  paper  with  the  chief  emphasis  on  the  materials 
coarser  than  clay  and  leave  the  problem  of  finer  materials  until 
further  studies  make  a  more  authoritative  statement  possible. 

Acknowledgements 
The  author  has  been  assisted  from  time  to  time  in  the  testing  of 
methods  and  apparatus  by  a  number  of  students  who  have  carried 
on  their  work  in  the  Sedimentation  Laboratory  of  the  State  Univer- 
sity of  Iowa.  Experience  in  mechanical  analysis  has  been  gained  as 
a  by-product  of  other  investigations,  chief  among  which  have  been 
the  studies  of  Atlantic  Coastal  Plain  terrace  gravels  for  the  U.  S. 
Geological  Survey  by  the  writer,  and  studies  of  Mississippi  delta 
sediments  for  the  War  Department  by  M.  S.  Littlefield  as  assistant 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  9 

to  Dr.  A.  C.  Trowbridge.  More  recently  Mr.  Littlefield  has  been 
engaged  in  a  study  of  molding  sands  for  the  Illinois  Geological 
Survey,  in  the  course  of  which  he  has  gained  much  experience  in 
methods  of  analyses  and  sampling.  To  him  and  to  a  number  of 
other  graduate  students  at  the  University  of  Iowa  the  writer  grate- 
fully acknowledges  his  indebtedness  for  suggestions  and  criticism. 
For  general  encouragement  and  critical  discussion  of  methods  and 
purposes  of  the  study  of  sediments  during  the  course  of  studies 
mentioned  above,  the  writer  is  especially  indebted  to  A.  C.  Trow- 
bridge, of  the  State  University  of  Iowa,  and  to  T.  W.  Vaughan  and 
M.  I.  Goldman  of  the  U.  S.  Geological  Survey. 

COLLECTION  OF  SAMPLES 

Size  of  Sample 

The  size  of  sample  to  be  collected  for  mechanical  analysis  de- 
pends on  a  number  of  considerations.  If  the  sample  is  for  a  single 
analysis  of  a  homogeneous  fine  grained  material  and  no  further 
examination  is  to  be  made,  the  amount  collected  may  be  small.  If, 
on  the  other  hand,  the  analysis  is  to  be  run  in  duplicate  or  the 
sample  is  of  a  coarse,  heterogeneous  material  and  the  separates  are 
to  be  studied  by  other  methods,  the  amount  must  be  much  greater. 
If  the  mechanical  composition  of  a  single  thin  lamina  of  fine  ma- 
terial is  to  be  determined  a  small  sample  will  be  sufficient,  and  in- 
deed in  such  a  ease  an  attempt  to  collect  a  larger  sample  is  likely  to 
result  in  the  inclusion  of  material  not  representative  of  the  lamina 
and  to  lead  to  less  accurate  results  in  the  end.  In  commercial  sam- 
pling it  is  usually  desired  to  know  the  average  composition  of  a 
certain  deposit  and  in  this  case  the  materials  of  different  beds  or  of 
different  areas  will  need  to  be  included  in  the  sample  in  proportion 
to  the  amounts  found  on  the  ground  in  case  a  single  sample  only  is 
to  be  analysed.  In  sampling  a  uniform  horizontal  series  of  beds 
which  are  unconsolidated  this  is  most  easily  accomplished  by  cutting 
down  a  uniform  channel  from  top  to  bottom.  This  results  in  a 
large  sample.  Any  sample  in  which  the  amount  of  material  is  con- 
trolled by  nonuniformity,  either  natural  or  artificial,  may,  after 
thorough  mixing,  be  reduced  in  size  by  splitting  to  the  limit  imposed 
by  the  sizes  of  the  largest  constituents  or  by  the  purposes  to  which 
the  sample  is  to  be  devoted.9 

The  size  of  sample  needed  for  an  accurate  mechanical  analysis 
bears  a  definite  relationship  to  the  coarseness  of  the  sediment.    In 


»  Milner,  H.  B.,  Introduction  to  Sedimentary  Petrology,  pp.  15-17,  London, 
1922. 


10 


IOWA  STUDIES  IN  NATURAL  HISTOKY 


general  it  may  be  stated  that  the  sample  should  be  large  enough  to 
include  several  fragments  which  fall  in  the  largest  grade  present  in 
the  deposit.  Several  fragments  may  be  interpreted  as  a  number 
sufficiently  large  so  that  the  probability  of  a  serious  accidental 
deviation  from  the  normal  number  of  such  fragments  in  a  sample 
collected  by  a  reliable  random  method  is  small.  This  number  de- 
pends in,  turn  on  the  percentage  of  the  whole  which  is  included  in 
the  coarse  grade  and  it  is  not  practicable  to  adopt  specific  theoretical 
standards.  It  is  important,  however,  that  the  collector  appreciate 
the  principle  relating  the  size  of  sample  to  the  sizes  and  abundance 
of  the  larger  constituents.  The  following  table  based  on  a  specific 
number  and  percentage  of  coarser  fragments  indicates  in  the  second 
column  the  smallest  size  of  sample  demanded  to  insure  satisfactory 
accuracy  in  determining  the  coarse  grade.  Several  practical  con- 
siderations are  of  importance.  In  general  it  is  hardly  profitable  to 
collect  less  than  125  grams,  even  of  a  very  fine  material,  if  it  is 
readily  obtainable  from  the  outcrop.  At  the  other  extreme  it  is 
rarely  practicable  for  the  geologist  to  collect  samples  as  large  as 
those  demanded  by  the  strict  requirements  of  accuracy.  Taking 
these  several  limitations  into  account  in  the  light  of  experience  both 
in  collecting  and  in  subsequent  analysis,  the  scale  of  sizes  given  in 
the  last  column  of  the  following  table  is  presented  as  a  working 
suggestion. 

TABLE    OF   SUGGESTED   MAXIMUM  AND   MINIMUM   WEIGHTS   OF 
SEDIMENT  SAMPLES^ 


Ideal  minimum  to  de- 

Ideal maximum  for 

Suggested 

termine  coarse 

convenient  analysis 

amount  of  col- 

Coarse Grade 

grade. 

in  6"  sieves11 

lected  sample. 

128-64  mm. 

256  kg. 

32  kg. 

64-32      > ' 

32    >' 

16    " 

32-16     " 

4    " 

8    » 

16-  8     " 

512  grams 

4    >> 

8-  4     » 

64       " 

1600  grams 

2    " 

4-  2     " 

200       " 

1    " 

2-  1     " 

25       » 

500  grams 

1-1/2   " 

25       " 

250       " 

1/2-1/4   " 

25       " 

125       » 

1/4-1/8     " 

25       » 

125       " 

1/8-1/16" 

25       " 

125       " 

io  The  first  column  gives  the  large  amounts  of  coarse  material  demanded  for 
valid  determination  of  coarse  grades.  The  second  column  indicates  the  amounts 
for  the  finer  grades  which  are  best  adapted  for  sifting  and  weighing.  The 
third  column  is  a  practical  compromise  from  the  first  and  second  columns  with 
amounts  of  the  finer  sediments  increased  to  give  additional  material  for  check- 
ing or  supplementary  study. 

11  In  case  the  collected  sample  is  larger  than  the  amount  needed  for  analysis, 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  11 

Containers 

It  is  important  in  collecting  samples  of  sediments  for  mechanical 
analysis  to  provide  plenty  of  containers  of  ample  size.  All  contain- 
ers should  be  tight  for  the  material  to  be  collected  and  should  be 
stout  enough  to  stand  much  wear  and  tear.  Loss  from  broken,  con- 
tainers is  practically  always  selective  and  remaining  contents  will 
be  of  little  or  no  value  in  mechanical  analysis.  Cloth  bags  are  most 
satisfactory  for  collecting  dry  materials  in  the  field.  They  are  dur- 
able and  sufficiently  tight  if  made  of  fine  material  and  a  number  of 
them  take  up  little  space  until  they  have  been  filled.  Wet  materials, 
and  especially  the  finer  clay  sediments  in  which  the  original  col- 
loidal condition  is  an  important  characteristic,  should  be  placed  at 
once  in  air  tight,  sealed  containers  which  are  entirely  filled  with  the 
sediment  and  contained  water.  Square  or  round  glass  jars  of  var- 
ious sizes  with  aluminum  screw  tops  may  be  obtained  from  dealers 
in  scientific  apparatus  and  are  convenient  for  wet  collecting.  Ordi- 
nary glass  fruit  jars  are  nearly  as  good  for  the  larger  samples,  some- 
what less  expensive  and  more  readily  obtainable  in  the  field. 

As  a  guide  in  ordering  sample  containers  the  following  tables  are 
presented. 

TABLE  OF  CAPACITIES  OF  CLOTH  BAGS 

(Allowing  length  to  tie  readily  at  the  top.) 


Width  and  length 

Width  and  length 

Capacity  by  weight 

Inches 

Centimeters 

of  dry  sand 

12  by  18 

36 

by  46 

10  kg. 

9  by  14 

23 

by  36 

5    " 

7  by    9 

18 

by  23 

2    " 

5  by    8 

13 

by  20 

1    " 

4  by    6 

10 

by  15 

500  gm. 

3  by    4V2 

8 

by  11 

200    " 

2  by    4 

5 

by  10 

100    " 

TABLE  OF  CAPACITIES  OF  JAES  AND  TUBES 

Type 

Height 

Outside  diameter 

Capacity  by  weight 
of  dry  sand. 

1  qt.  Mason 

190  mm. 

105  mm. 

1400  gm. 

1  pt.       " 

140     " 

90     " 

700    " 

%  pt.  jar 

110     >> 

90     " 

400    " 

16  oz.  Screw 

150     " 

85     " 

800    " 

8  oz.       " 

145     " 

65  mm.  square 

400    " 

Bound  bottom 

shell  vial 

110     " 

30  mm. 

35    " 

y  > 

60     " 

12     " 

6    " 

split  it  down.  In  case,  when  analysing  a  coarse  sample,  the  fines  at  any  stage 
amount  in  toto  to  much  more  than  the  suggested  maximum  for  convenient 
analysis  for  that  grade,  the  analysis  should  be  broken  at  that  point  and  the  com- 
bined and  mixed  fines  split  down  to  suitable  amount  before  proceeding.  The 
limit  is  not,  of  course,  fixed  or  arbitrary,  but  in  general  amounts  greatly  in 
excess  of  those  given  should  not  be  passed  through  the  sieves. 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

Notation  and  Labeling 
Samples  should  be  accurately  labelled  so  as  to  indicate  the  exact 
locality,  the  field  name  of  the  sediment,  the  beds  or  part  of  the  out- 
crop represented,  the  proper  name  of  the  formation,  the  method  of 
sampling,  the  date  and  the  name  of  the  collector.  The  method  of 
recording  these  data  will  usually  depend  on  the  form  of  the  col- 
lectors field  notes.  The  main  desiderata  are  the  same  as  for  ordinary 
field  notes ;  easy  cross  reference  between  the  samples,  the  field  note- 
book and  the  field  map;  from  any  one  to  either  of  the  other  two. 
The  writer  prefers  to  place  only  a  number  on  the  sample  and  to 
record  all  other  data  in  the  field  notebook  under  the  number.  After 
trying  a  number  of  schemes  for  numbering  and  lettering  notes  and 
localities  he  has  adopted  the  simple  plan  of  numbering  his  field 
stations  serially  in  Arabic  numbers,  starting  from  1  at  the  beginning 
of  each  project.  This  system  does  not  indicate  automatically  as  do 
some  others  the  map  location  of  the  station.  It  is  necessary  in  using 
it  to  make  and  number  the  map  location  and  to  make  such  route 
notes  for  each  day's  travel,  referring  to  the  maps  used,  that  another 
person  can  readily  find  the  stations  in  turning  from  the  notebook 
to  the  map.  This  slight  disadvantage  is  more  than  offset  by  a  num- 
ber of  advantages  which  are  especially  important  when  large  num- 
bers of  samples  are  collected.  In  the  first  place,  in  the  storage  of 
samples  and  of  the  separates  derived  by  mechanical  analysis  the 
Arabic  numerical  scheme  is  the  only  one  which  presents  an  entirely 
obvious  sequence  for  arrangement.  Systems  of  letters  and  numbers, 
map  grating  systems  or  page  and  notebook  notations  are  all  more 
complicated  and  less  obvious  and  entail  much  more  confusion  if 
several  hundred  samples  are  being  analysed  and  later  studied  in  the 
form  of  several  thousand  separates.  A  second  advantage  is  the  ease 
with  which  notes,  maps,  samples  and  photographs  are  all  handled  in 
the  same  series  of  numbers.  The  notes  and  the  map  stations  are 
complete;  i.e.,  every  number  in  the  consecutive  series  is  represented. 
The  samples  and  photographs  carry  the  numbers  pertaining  to  the 
stations  at  which  they  were  taken  but  there  are  usually  stations  at 
which  no  samples  or  photographs  were  taken  and  this  series  is  a 
broken  one.  Every  number  which  is  present,  however,  fits  into  one 
place  and  only  one  place  in  the  scheme.  A  third  advantage  is  of 
importance  to  persons  or  institutions  collecting  large  numbers  of 
samples  in  connection  with  several  projects.  The  several  series  of 
samples,  each  numbered  from  1  up,  may  be  combined  in  one  decimal 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  13 

series  by  adding  ciphers  and  key  digits  at  the  left.  Thus  in  a  five 
place  system  the  first  5000,  a  twentieth  of  the  whole,  may  be  divided 
in  any  order  as  occasion  arises  into  number  allotments  of  2000, 1000, 
1000,  400,  300,  200,  and  100.  Such  a  system  indicates  clearly  to 
custodians  the  position  in  the  collections  which  should  be  occupied 
by  the  samples  collected  with  a  given  project.  Specimens  numbered 
in  the  field  with  the  station  digits  can  readily  have  the  project  key 
numbers  added  at  the  left  when  an  appropriate  block  of  numbers 
has  been  assigned.  The  following  tabulation  will  illustrate  the 
principle : 

00001    to  00999     Project  A. 

01001     to  01999  "     B. 

O2001     to  03999  »      C. 

04001     to  04999     Miscellaneous  minor  projects. 

04001  to     04099    Project  D. 

04101  to     04399  "      E. 

04401  to     04599  "      F. 

04601  to     04999  "       G. 

Methods  and  Precautions  in  Collecting 
A  sample  which  has  been  properly  collected  is  in  every  respect  a 
miniature  representative  of  the  deposit  from  which  it  came.  From 
certain  types  of  materials  such  a  sample  is  obtained  with  little  or 
no  difficulty  but  in  collecting  from  most  of  the  natural  sediments 
great  care  is  needed  to  guard  against  one  or  more  sources  of  error. 
If  the  material  is  in  place  in  its  natural  bedded  or  massive  condi- 
tion the  portion  which  is  exposed  may  be  excessively  coarse  because 
of  the  washing  away  of  the  finer  constitutents  and  retention  of  the 
larger  pebbles  or  sand  grains  in  the  face  of  the  bank.  This  is  a  com- 
mon condition  in  vertical  or  steep  gravel  banks  and  leads  to  a  false 
impression  of  the  abundance  of  the  pebbles  as  well  as  to  error  in  the 
analysis  in  case  a  sample  is  collected  without  cutting  away  the  sur- 
face pebbles.  Gentler  slopes  may  be  the  sites  of  accumulation  of 
the  finer  constituents  washed  from  above  and  samples  taken  here 
will  show  too  high  a  percentage  of  the  finer  grades  unless  care  is 
taken  to  dig  well  into  the  deposit  before  the  sample  is  collected.  In 
collecting  from  any  situation  it  is  necessary  to  collect  all  the  mater- 
ial from  a  given  portion  of  the  mass.  The  accidental  falling  of 
material  from  the  bank  as  the  sample  is  cut  away  may  be  highly 
selective  and  result  in  abnormal  loss  in  certain  grades  unless  pre- 
cautions are  taken  to  catch  all  the  material.  In  collecting  coarse 
material  from  a  bank  a  cloth  spread  to  catch  the  material  cut  from 
the  cleaned  outcrop  offers  the  best  procedure.  For  finer  material  it  is 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

convenient  to  hold  a  scoop-funnel  of  the  type  shown  in  Figure  1 
indirectly  against  the  outcrop.  The  scoop  and  bag  may  be  held 
with  one  hand  and  the  cutting  done  with  a  hammer,  knife,  or  other 
tool  with  the  other  hand.  In  collecting  heterogeneous  material  in 
which  great  differences  are  readily  visible  to  the  eye  it  is  desirable 
to  decide,  before  starting  to  take  a  sample,  what  its  limits  shall  be. 
This  decision  is  best  made  by  a  strictly  random  method  such  as  tak- 
ing to  a  given,  depth  all  material  covered  by  a  square  of  cloth  laid 
by  chance  over  the  outcrop  or  by  taking  all  material  within  a  given 
radius  of  a  random  point.  Some  such  predetermined  convention 
relieves  the  collector  of  disconcerting  uncertainty  in  regard  to  re- 


Fig.    1.      Collecting    scoop    funnel 
used  in  filling  bags  at  the  outcrop. 

taining  or  rejecting  the  abnormal  material  which  seems  commonly 
to  fall  at  the  last  moment  or  to  lie  just  at  the  limit  of  the  collecting 
area.  Collecting  gravel  which  is  strewn  over  a  beach  or  samples  of 
pebbles  on  the  surface  is  exceedingly  difficult  to  perform  in  an  un- 
prejudiced fashion  and  the  most  rigorous  and  unswerving  decisions 
in  regard  to  the  area  to  be  covered  and  the  sizes  to  be  considered 
must  be  made  before  starting  the  collecting.  Without  these  pre- 
cautions it  is  inevitable  that  there  will  be  selective  errors  based  on 
shape,  color,  rock  material,  size  or  degree  of  exposure,  some  of  which 
may  be  just  the  sort  to  vitiate  conclusions  based  on  subsequent  stu- 
dies of  the  sample. 

If  a  sample  is  taken  to  represent  a  given  stratum  or  other  small 
portion  of  a  deposit  it  is  imperative  that  material  from  adjacent 
layers  be  excluded  and  the  more  so  the  more  the  materials  differ 
from  one  another.  In  case  a  certain  amount  of  contamination  of 
any  sort  ^s  unavoidable  in  practice,  note  should  be  made  of  the 
amount  and  probable  effect  of  the  foreign  material.  Samples  of 
sand  and  gravel  collected  under  water  are  likely  to  be  washed  more 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  15 

or  less  free  of  finer  grades  of  collecting  and  this  condition  should 
be  noted  to  guide  later  study  and  interpretation. 

Procedure  in  Surficial  Rock  Collecting 
The  amount  of  equipment  used  in  this  type  of  collecting  depends 
largely  on  the  means  of  travel  and  the  distance  of  the  collecting 
ground  from  headquarters.  Clean  samples  can  be  collected  with  a 
minimum  of  equipment  if  sufficient  care  is  used,  but  if  one  is  to 
collect  large  numbers  of  samples  and  is  traveling  by  automobile 
the  work  may  be  done  more  readily  and  conveniently  and  with  more 
uniformity  if  more  extensive  equipment  is  used.  The  prime  re- 
quisite is  the  container.  For  most  surficial  collecting,  especially  if 
the  samples  are  to  be  shipped  a  distance,  the  cloth  bag  is  most  sat- 
isfactory. If  the  pebbles  of  a  gravel  are  weathered  so  as  to  be 
fragile  or  if  it  is  desired  to  preserve  the  structure  of  a  gravel  or 
other  sediment,  it  will  be  necessary  to  wrap  the  specimen  carefully 
and  perhaps  to  store  it  in  a  jar  or  some  other  sort  of  rigid  container. 
For  collecting  loose  sediments  a  hammer  with  the  transverse  chisel 
type  of  point  is  most  convenient.  If  large  samples  are  desired  or  if 
samples  are  to  be  secured  by  splitting  material  cut  down  from  the 
face  of  a  bank,  a  sample  cloth  is  needed.  This  may  range  from  30" 
to  6'  square  according  to  conditions.  If  made  of  oilcloth  or  other 
smooth  surfaced  material  it  may  be  cleaned  more  completely,  but 
for  most  dry  sediments  a  cloth  of  drill  or  denim  may  be  kept  suffi- 
ciently clean  and  is  more  flexible  and  convenient  to  handle  and  is 
free  from  surface  cracking. 

Sheet  metal  scoops  having  flat  bottoms  and  low  vertical  sides  at 
one  end  and  formed  to  a  complete  square  or  round  aperture  at  the 
other  end  are  very  useful  both  in  the  field  and  in  the  laboratory. 
(Figure  1.)  Several  sizes  of  these  having  their  end  apertures  cor- 
responding to  the  sizes  of  bags  used  are  desirable.  The  bag  may  be 
drawn  over  the  aperture  and  the  scoop  and  bag  thus  held  with  one 
hand  against  the  outcrop  for  direct  collecting.  Pick  and  shovel  are 
needed  where  considerable  digging  is  to  be  done.  In  collecting  ma- 
terial from  thin  laminae  or  from  the  thin  surface  layers  of  beaches 
or  rill  deposits  a  small  spoon  or  a  putty  knife  is  useful. 

Two  general  types  of  collecting  situations  may  be  distinguished, 
the  vertical  or  steep  bank  and  the  horizontal  surface.  The  former 
is  the  more  satisfactory  from  which  to  collect  and  in  collecting  from 
horizontal  surfaces  it  is  best  to  dig  into  the  deposit  sufficiently  to 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

expose  its  bedding  if  such  exists  and  collect  from  the  wall  of  the 
excavation. 

The  first  operation  in  collecting  from  any  situation  is  to  clean  the 
face  of  the  outcrop  and  get  back  to  fresh  normal  material.  In  do- 
ing this  it  is  wise  to  clean  a  considerably  larger  surface  than  will  be 
needed  for  the  sample  and  if  the  sediment  will  hold  together  it  is 
well  to  clean  a  channel  around  the  part  which  is  to  be  collected, 
leaving  it  protruding  from  the  rest.  In  the  case  of  horizontal  beds 
in  a  vertical  bank  the  strata  above  and  below  the  layer  to  be  sampled 
should  be  cut  back  if  possible,  leaving  the  latter  ready  to  fall  with- 
out contamination  into  the  scoop,  bag  or  cloth  wThieh  is  placed  under 
it.  In  the  case  of  a  thick  layer  of  uniform  material  being  sampled 
this  procedure  may  be  reversed  and  the  sample  made  up  of  several 
scoops  or  shovels  full  of  material  taken  without  discrimination  from 
the  bottom  and  sides  of  a  clean  hole,  taking  care  that  no  material 
falls  in  from  the  edges.  When  a  large  sample  of  gravel  is  taken  it 
is  sometimes  necessary  to  pin  the  sampling  cloth  tightly  at  the  foot 
of  the  undisturbed  outcrop,  using  a  couple  of  spikes  or  surveyors 
tally  pins. 

Samples  of  heavy  concentrates  from  thin  surface  layers  on  beaches 
and  similar  situations  should  be  scraped  from  the  surface  with  a 
spoon  or  knife  using  care  not  to  include  material  from  the  under- 
lying layers.  In  such  samples,  which  are  likely  to  be  small  in 
amount,  very  slight  contaminations  may  introduce  considerable  er- 
rors in  the  composition. 

Procedure  in  Indurated  Rock  Collecting 
The  same  general  principles  hold  in  the  collecting  of  indurated 
rock  as  for  the  loose  sediments.  If  the  rock  can  be  disintegrated  by 
treatment  with  acid  or  otherwise,  it  is  better  to  collect  a  single  large 
sample  and  analyse  the  whole  of  it  in  the  laboratory  than  to  collect 
a  number  of  small  loose  pieces  which  may  vary  considerably  from 
the  normal  rock  in  composition.  However,  it  is  commonly  difficult 
if  not  impossible  to  disintegrate  the  rock  by  artificial  means  and 
analysis  of  a  considerable  quantity  of  the  weathered  debris  from  the 
rock  is  preferable  to  no  examination  at  all  of  mechanical  composi- 
tion. If  the  composition  is  to  be  determined  in  part  from  study  of 
plane  polished  surfaces  or  of  thin  sections,  those  cut  normal  to  the 
stratification  are  preferable  to  those  cut  parallel  to  it  and  this  con- 
sideration should  be  borne  in.  mind  in  collecting.  In  the  cases  of 
coarse  conglomerates,  scale  photographs  of  large  exposures  normal 


MECHANICAL  ANALYSIS  OP  SEDIMENTS  17 

to  the  bedding  may  be  much  more  valuable  in  determining  mechan- 
ical composition  than  a  small  specimen  which,  moreover,  offers  dif- 
ficulty in  disaggregation. 

PKEPARATION  OF  SAMPLES 
Disaggregation  of  Coarse  Materials 

No  very  well  defined  methods  for  the  disaggregation  of  strongly 
indurated  coarse  sediments  appear  to  have  been  described.12  Con- 
glomerates and  sandstones  which  consist  of  noncalcareous  grains 
cemented  by  calcium  carbonate  may  be  disintegrated  by  treatment 
with  dilute  hydrochloric  acid.  If  a  conglomerate  is  not  too  strong- 
ly cemented  it  may  be  broken  up  and  a  large  fraction  of  the  pebbles 
saved  intact  for  analysis  by  sifting.  This  is  best  done  in  stages  by 
hand,  using  a  hammer  only  as  necessary.  In  some  cases  disaggrega- 
tion may  be  achieved  by  repeated  heating  and  quenching.13  Many 
gravels,  tills  and  other  coarse  sediments  are  only  slightly  indurated 
by  compacting  or  incipient  cementation  and  only  need  thorough 
wetting,  and  maceration  in  water  to  disaggregate  them.  In  such 
coarse  gravels  it  is  best  to  handle  the  process  in  stages  as  described 
in  the  section  on  analysis  by  sifting.  The  writer  has  found  so  much 
variation  in  the  coarser  sediments  in  the  degree  and  kind  of  indura- 
tion that  the  method  of  successive  fractionation  and  carrying  on  the 
disaggregation  by  hand,  either  with  the  fingers  or  with  a  wood  or 
rubber  pestle,  seems  to  be  as  satisfactory  as  any.14  In  breaking  up 
dry  aggregates  in  sands  it  is  convenient  to  rub  them  on  a  white 
paper  card  with  the  fingers  successively  removing  the  fines  and 
changing  to  fresh  cards.  The  soiling  of  the  card,  while  it  means 
slight  loss,  gives  a  vivid  idea  of  the  progress  achieved  and  enables 
the  analyst  to  follow  the  process  closely.  Shaking  in  a  vigorous 
mechanical  shaker  disintegrates  dry  sediments  to  a  considerable  ex- 
tent but  caii  hardly  be  said  to  complete  the  process  nor  to  work  suc- 
cessfully on  material  which  would  not  yield  much  more  readily  to 
wetting  and  washing. 

After  a  large  sample  has  been  mixed  with  sufficient  water  to  make 
a  soft  mud  and  has  been  macerated  by  hand  the  coarse  particles  can 


12  Cayeux,  L.,  Introduction  a  1  'Mu&e  Petrographique  des  Roehes  Sediment- 
aires,  Paris,  pp.  4-5,  1916. 

Hatch,  F.  H.,  and  Rastall,  R.  H.,  Textbook  of  Petrology,  The  Sedimentary 
Rocks,  p.  341,  London,  1913. 

is  Cayeux,  L.,  Op.  tit.,  pp.  4-5,  1916. 

i*  Dake,  O.  L.,  Op.  tit.,  p.  156. 


18  IOWA  STUDIES  IN  NATUEAL  HISTORY 

be  taken  out  by  washing  the  whole  on  the  appropriate  sieve.  Fine 
silts  and  clays  of  the  matrix  will  reaggregate  in  drying  and  analysis 
is  much  expedited  if  a  small  sample  of  the  fines  is  reserved  before 
wetting  the  material  so  that  the  fines  of  the  wetted  sample  may  be 
rejected  without  drying. 

Sample  Splitting 

The  splitting  of  a  sample,  though  it  may  consist  in  the  establish- 
ment of  several  equal  similar  parts,  usually  consists  in  the  separa- 
tion from  the  larger  sample  of  one  small  part  which  is  as  nearly  as 
possible  identical  in  composition  and  other  characteristics  with  the 
main  sample.  It  may  be  practiced  for  a  number  of  purposes  among 
which  are  the  following:  (1)  Reduction  of  the  size  of  a  large  com- 
posite or  heterogeneous  field  sample  to  form  the  collected  sample  for 
the  laboratory.  (2)  Removal  from  a  large  sample  of  one  of  more 
normal  small  fractions  for  analysis  or  other  study.  (3)  Successive 
reduction  of  fines  in  the  course  of  analysis.  In  working  with  sedi- 
ments one  of  the  first  lessons  that  is  driven  home  is  the  strong  tend- 
ency that  exists  through  the  operation  of  various  physical  and  chem- 
ical factors  for  like  materials  to  become  segregated.  In  splitting 
samples  for  mechanical  analysis  this  tendency  will  be  met  on  all 
sides  and  must  be  largely  overcome  if  success  is  attained.  Not  all 
the  details  of  such  segregation  are  known  but  a  few  examples  will 
serve  to  illustrate  the  extent  to  which  the  tendency  is  everywhere 
present.  If  a  small  quantity  of  sand  with  a  few  very  large  grains 
is  shaken  in  a  bottle  it  is  seen  that  there  is  a  certain  amount  of  separ- 
ation on  the  basis  of  size.  When  a  similar  sand  is  poured  from  a 
parellel-sided  scoop  it  is  noted  that  the  coarser  particles  are  more 
abundant  adjacent  to  the  sides.  If  it  is  poured  through  a  funnel 
the  central  portion  of  the  stream  differs  from  the  peripheral  por- 
tions. The  sliding  and  rolling  of  a  heterogeneous  sediment  down 
the  sides  of  a  pile  results  in  segregation  which  is  apparent  to  the 
eye.  From  these  few  examples,  which  may  be  multiplied  almost 
indefinitely  by  anyone  who  will  spend  a  few  minutes  on  a  sandpile, 
it  is  readily  seen  that  detrital  material  in  which  there  are  diverse 
sorts  of  grains  cannot  be  handled  without  putting  in  operation  some 
of  the  factors  which  bring  about  segregation.  It  is  equally  evident 
that  these  tendencies,  unless  studious  attention  is  given  to  the  prob- 
lem of  thwarting  them,  will  result  in  abnormal  fractions  which  will 
vitiate  any  results  obtained  from  their  study. 

Most  of  the  splitting  or  quartering  devices  which  are  commonly 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  19 

used  are  based  on  the  idea  of  establishing  two  nearly  equal  portions 
by  throwing  alternating  small  portions  or  streams  of  flowing  ma- 
terial into  each.  Such  devices  work  satisfactorily  if  the  quantity 
of  material  is  large  in  proportion  to  the  size  of  the  larger  constitu- 
ents and  if  there  is  a  considerable  number  of  these.  The  type  known 
as  the  Jones  sampler  is  constructed  on  this  principle  and  does  very 
satisfactory  work.  The  writer  has  purchased  scoop  samplers  in 
which  the  material  is  poured  on  the  five-channelled  scoop  from  the 
solid  scoop.  The  material  falling  between  the  channels  constitutes 
one  fraction  and  that  falling  into  the  channels  another.  The  solid 
scoop  furnished  with  some  of  these  outfits  is  of  the  same  width  as 
five  channels  and  four  spaces;  thus  the  abnormal  edge  portions 
from  the  solid  scoop  both  fall  into  the  channels  and  therefore  into 
one  fraction,  whereas  one  should  fall  on  a  channel  and  one  on  a 
space.  The  user  of  such  apparatus  must  guard  against  poor  design- 
ing of  this  sort  since  the  makers  are  not  always  attentive  to  the 
correct  theoretical  principles.  Large  samplers  of  the  Jones  type 
will  do  satisfactory  work  on  coarse  material  with  sufficient  amounts 
of  material.  In  splitting  small  samples  of  coarse  material  it  seems 
permissible,  and  in  fact  essential,  that  the  coarser  grade  and  per- 
haps the  next  be  separated  out  on  a  sieve  and  separated  by  inspec- 
tion into  as  many  equal  and  comparable  portions  as  may  be  required 
and  these  portions  added  to  the  fractions  which  have  been  estab- 
lished by  splitting  by  one  of  the  automatic  methods.  For  any  grade 
of  large  fragments  in  which  there  are  so  few  pieces  that  they  may 
readily  be  inspected  at  a  glance  this  method  of  splitting  is  better 
than  one  which  depends  on  the  laws  of  probability  since  these  oper- 
ate to  the  end  here  desired  only  when  numbers  are  large. 

The  method  of  splitting  known  as  quartering,  as  applied  to  the 
collecting  of  coal  and  ore  samples,  consists  of  the  formation  on  a 
sample  cloth  of  a  conical  pile  of  well  mixed  material  which  is  cut 
into  quarters  by  two  right  angled  separations  and  the  alternate 
quarters  rejected.  The  remaining  two  quarters  are  again  mixed  by 
lifting  and  rolling  the  material  on  the  cloth,  alternately  forward 
and  backward  from  left  and  right.  A  new  conical  pile  is  again 
quartered  as  before.  The  procedure  is  continued  until  the  sample 
is  reduced  to  the  size  required.  After  trying  this  method  with 
gravels  the  writer  is  of  the  opinion  that  it  is  much  less  successful  in 
maintaining  normal  fractions  for  other  kinds  of  analysis.  The  tech- 
nique of  coal  sampling  specifically  requires  crushing  of  the  large 


20  IOWA  STUDIES  IN  NATURAL  HISTORY 

sample  to  a  half  inch  mesh  which  not  only  insures  that  there  be  a 
large  number  of  fragments  but  also  that  large  fragments  be  elim- 
inated. The  main  purpose  of  gravel  collection  for  mechanical 
analysis  forbids  the  use  of  these  two  principles  which  are  essential 
to  the  quartering  method.  The  latter  method  works  well  with  rela- 
tively homogeneous  materials,  but  these  are  also  well  handled  by 
most  of  the  other  methods. 

A  coarse  sediment  which  has  been  well  mixed  by  stirring  and 
beating  in  a  pan  or  on  a  cloth  may  be  split  with  fair  accuracy  by 
throwing  successive  spoons  or  scoops  full  into  alternate  fractions  as 
it  is  transferred  from  the  pan  or  cloth.  In  this  method  care  should 
be  taken  to  avoid  the  systematic  dipping  of  the  spoonsful  for  the 
two  fractions  from  different  parts  of  the  original  mixture.  The 
spoon  or  scoop  should  be  filled  quite  as  monotonously  as  possible 
from  the  mixture  and  emptied  alternately  to  one  side  and  the  other. 

"Well  mixed  material  which  is  poured  in  a  broad  stream  from  a 
pan  is  reasonably  wrell  split  if  the  stream  is  made  to  flow  half  into 
one  container  and  half  into  another  adjacent  to  it.  The  stream 
should  be  made  to  flow  symmetrically  with  the  edges  as  nearly  as 
possible. 

It  will  be  noted  that  nearly  all  the  methods  mentioned  involve 
splitting  the  sample  into  halves  and  then  one  of  the  halves  into 
quarters  and  so  on.  This  is  an  essential  part  of  the  process.  Any 
attempt  to  separate  the  sample  into  a  large  and  a  small  fraction  at 
once  is  likely  by  the  nature  of  necessary  devices  to  bring  about  some 
segregation  favoring  the  accumulation  of  coarser  material  in  one 
fraction  or  the  other  and  vitiate  the  results. 

ANALYSIS  BY  SIFTING 

General  Principles 

In  practice,  analysis  by  sifting  can  be  applied  to  the  separation 
of  sediments  down  to  a  fineness  of  about  .05  mm.  or  .002  inch.  From 
this  size  up  to  10  em.  or  about  4  inches,  sifting  can  be  conveniently 
accomplished  in  a  series  of  testing  sieves.  Cobbles  larger  than  this 
size  are  not  ordinarily  present  in  numbers  in  the  samples  analysed 
by  the  geologist  and  can  be  discriminated  by  individual  measure- 
ment. 

Some  investigators  in  the  past  have  advocated  the  use  of  sieves 
with  round  holes.  These  have  the  advantage  that  the  sizes  of  the 
openings  can  be  determined  with  great  uniformity  and  that  they 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  21 

may  be  readily  made  from  sheet  metal  without  elaborate  special 
equipment.  It  has  also  been  urged  in  their  favor  that  a  round  hole 
is  naturally  more  appropriate  for  the  separation  of  the  somewhat 
rounded  particles  than  is  any  other  shape  of  opening.  In  spite  of 
these  considerations  the  woven  wire  sieve  with  square  openings  has 
so  many  points  in  its  favor  that  it  has  been  generally  adopted. 
Woven  wire  cloth  is  now  made  in  a  very  great  variety  of  sizes  of 
opening,  and  diameter,  and  material  of  wire.  Double  crimped  wire 
cloth  keeps  its  original  uniformity  of  spacing  so  successfully  even 
with  considerable  rough  handling  that  one  of  the  former  objections 
to  the  woven  wire  sieve  has  been  overcome.  The  woven  wire  cloth 
can  be  made  with  much  smaller  openings  than  is  practicable  in  the 
sieve  made  by  punching  or  drilling  round  holes  in  sheet  metal. 

Some  workers  advocate  the  use  of  bolting  cloth  in  clamp  rings  be- 
cause of  the  ease  with  which  new  and  clean  cloth  may  be  inserted. 
This  method  is  doubtless  of  value  when  samples  of  sands  of  diverse 
sorts  are  to  be  studied  for  mineral  content  and  it  is  desired  to  use 
extreme  care  to  avoid  contamination,  but  it  seems  hardly  applicable 
to  mechanical  analysis  to  a  grade  scale  of  the  sort  suggested  below. 

As  to  the  shape,  it  is  probable  that  the  round  hole  should  be  re- 
garded as  slightly  more  appropriate.  However,  since  the  minor 
cross-sections  of  most  of  the  particles  passed  by  any  sieve  are  neither 
round  nor  square  but  more  or  less  intermediate,  it  is  probable  that 
the  difference  in  amount  between  the  material  passed  by  square  and 
round  opening  sieves  of  the  same  diameter  of  opening,  is  very  small. 
To  be  sure,  the  writer  does  not  consider  that  analyses  made  in  the 
two  types  of  sieves  would  be  interchangeable  but  merely  that  in 
the  proportions  of  materials  in  successive  grades  one  type  of  analysis 
is  probably  as  good  an  approximation  to  the  ideal  hydraulic  classifi- 
cation as  is  the  other. 

Choice  of  Grade  Scale 
The  ideal  representation  of  mechanical  composition  is  a  smooth 
curve  showing  the  continuous  distribution  of  sizes  in  their  proper 
proportions  from  one  end  to  the  other  of  the  range.  Such  a  result  is 
only  to  be  attained  by  careful  individual  measurements  on  all  the 
constituent  fragments  of  the  material  in  hand.  Except  for  pur- 
poses of  illustration  or  investigation  as  applied  to  a  very  limited 
amount  of  material,  such  procedure  is  not  practicable  and  less  labor- 
ious approximate  methods  must  be  chosen.  The  most  obvious  scheme 
is  to  divide  the  material  into  classes,  determining  the  amounts  in  the 


22 


IOWA  STUDIES  IN  NATURAL  HISTORY 


several  classes  and  thus  indicating  the  distribution  of  the  material 
in  point  of  sizes  of  particles.  If  a  large  number  of  classes  is  estab- 
lished the  results  will  approach  those  attained  by  individual  mea- 
surements, but  at  the  same  time  the  operation  becomes  more  time 
consuming.  Whether  a  large  number  of  classes  of  small  range  be- 
tween their  upper  and  lower  size  limits  or  a  small  number  of  large 
range  are  to  be  used  must  be  determined  according  to  the  use  to 
which  the  analysis  is  to  be  put  and  whether  the  greater  expense  of 
the  former  alternative  is  justified  by  the  greater  accuracy. 

In  choosing  the  classes  into  which  the  material  is  to  be  divided  the 
limits  of  the  several  classes  may  be  set  according  to  a  number  of 
different  considerations.  In  the  case  of  materials  for  commercial 
use  certain  definite  size  limits  governed  by  precedent  or  the  capacity 
of  equipment  may  be  the  critical  limits  in  the  analysis.  Too  often, 
in  the  ease  of  geologists  making  mechanical  analyses,  expediency 
has  governed  and  the  grade  scale  has  been  determined  by  the  series 
of  sieves  which  chanced  to  be  available  with  little  attention  to  the 
fitness  of  the  several  size  limits.  The  result  has  been  that  analyses 
have  been  made  to  a  great  variety  of  grade  scales,  many  of  which 
were  ill  adapted  to  the  purpose  in  hand  and  all  of  which,  because  of 
the  great  variety,  have  hindered  direct  comparison.  No  argument 
is  needed  to  indicate  the  great  desirability  of  the  use  of  the  same 
grade  scale  by  investigators  who  are  working  in  the  same  general 
field,  such  as  geology.  In  choosing  the  scale  for  general  use  it  is 
well  to  consider  those  which  have  been  used  in  the  past.  These  are 
of  several  sorts  as  follows : 

In  the  following  table  are  given  four  types  of  grade  scales  which 
have  been  used  in  making  mechanical  analyses. 

TABLE  OF  GRADE  SCALES^ 


A 

B 

C 

D 

1.000" 

1.000  mm. 

2.33  mm. 

8.  mm. 

.500" 

.500   " 

1.66   » 

4   " 

.250" 

.250  " 

1.17  " 

2   " 

.100" 

.100   " 

.833  " 

1   " 

.050" 

.050   ' ' 

.589  " 

1/2   » 

.025" 

.025   " 

.417  " 

1/4   » 

etc. 

etc. 

.295   " 

1/8   » 

.208  " 

1/16  " 

.147  " 

1/32  " 

.104   " 

etc. 

.074  " 

etc. 

15  Dake,  C.  L.,  Op.  cit.,  p.  152.    Holmes,  A.,  Op.  cit.,  p.  197. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  23 

These  scales  are  tabulated  in  this  form  not  to  show  comparisons 
between  them  but  to  show  the  ratio  and  starting  point  characteristic 
of  each.  Scales  A,  B,  and  D  have  simple  integer  starting  points, 
one  inch,  one  millimeter  and  one  millimeter  respectively.  Scales  A 
and  B  are  hybrid  scales  in  which  two  different  ratios  are  used  to 
secure  an  approximately  uniform  ratio  and  at  the  same  time  to 
make  every  third  grade  limit  coincide  with  a  decimal  submultiple. 
Scales  C  and  D  are  equal  ratio  scales  (within  limits  of  error  in  con- 
struction of  sieves),  the  ratios  being  the  square  root  of  2,  and  2, 
respectively.  Scale  C  starts  from  the  exhaustively  calibrated  200 
mesh  sieve  used  as  the  basis  of  fineness  specifications  of  Portland 
Cement.  Scale  D  combines  the  1  millimeter  starting  point  with  a 
uniform  ratio  of  2.16 

There  have  been  numerous  variations  of  these  types  used  in  prac- 
tice and  there  are  a  number  of  nonuniform  but  approximate 
geometric  scales  represented  by  the  systems  of  sieves  in  which  the 
coarseness  is  designated  by  the  number  of  meshes  to  the  inch.  Since 
in  the  past  and  to  some  extent  at  present  the  size  of  wire  used  in 
making  these  sieves  has  not  been  uniform  there  is  much  variation 
in  the  actual  opening  sizes  and  a  number  of  different  grade  scales 
result.17 

In  too  many  instances  in  the  past  and  occasionally  even  at  the 
present  time  the  sizes  are  indicated  only  by  stating  the  mesh,  a 
designation  which  is  next  to  useless  unless  the  critical  data  are  given 
elsewhere  in  the  paper  and  in  that  event  needlessly  cumbersome. 

In  all  the  scales  which  have  been  used  in  the  past  there  is  tacit 
recognition  of  the  essential  correctness  of  the  constant  ratio  of 
geometrical  scale.  The  arguments  in  favor  of  such  a  scale  have 
been  stated  by  the  writer  and  others  elsewhere  and  need  not  here 
be  repeated.18  Several  possibilities  present  themselves  in  the  choice 
of  ratio,  of  starting  point  and  of  system  of  mensuration.  Scientific 
work  is  now  practically  all  carried  on  in  metric  units  and  this  sys- 
tem seems  best  adapted  to  the  mechanical  analysis  grade  scale.  One 
of  the  cardinal  points  of  the  metric  system  is  its  expansion  on  the 

16  Cayeux,  L.,  Op.  tit.,  pp.  34-36,  Paris,  1916. 

Mohr,  E.  C.  Jul.,  Bulletin  In  Department  de  L 'agriculture  aux  Indes  Neer- 
landaises,  No.  16,  Buitenzorg,  1910. 

17  Milner,  H.  B.,  Introduction  to  Sedimentary  Petrography,  p.  18,  London, 
1922. 

isWentworth,  C.  K,  A  Scale  of  Grade  and  Class  Terms  for  Clastic  Sedi- 
ments:    Journal  of  Geology,  Vol.  XXX,  p.  382,  1922. 


24 


IOWA  STUDIES  IN  NATURAL  HISTORY 


decimal  basis.  Desire  to  use  certain  of  the  simple  decimal  fractions 
has  led  to  such  scales  as  B  in  the  table  above.  Scales  such  as  the 
following  in  which  the  ratios  are  small  integer  roots  of  10  have  been 
suggested  by  various  investigators  but  so  far  as  known  to  the  writer 
have  not  been  used  in  practice. 


E. 


Ratio  V10 

10.000      m 

3.162 

1.000 

.3162 

.1000 

.03162 

.01000 


Ratio  V10 

10.000       m 
4.641 
2.154 
1.000 

.4641 

.2154 

.1000 


These  scales  have  the  advantages  of  return  to  the  submultiples  of 
ten  at  uniform  intervals  and  that  the  number  of  decimal  sequences 
to  be  carried  in  mind  is  small.  On  the  other  hand,  it  is  impossible 
to  express  them  in  common  or  vulgar  fractions. 

The  scale  made  up  of  multiples  and  submultiples  of  2  starting 
from  1  millimeter  is  probably  most  readily  visualized  of  all.  (Scale 
D.)  The  ideal  scale  would  be  possible  if  our  system  of  numeration 
were  a  sexadecimal  system  instead  of  the  arabic  decimal  system. 
Then  we  should  be  able  to  use  halves,  quarters  and  eighths  of  the 

TABLE  I 

The  Grade  Terms 


The  Pieces 

The  Aggregate 

The  Indurated  Rock 

Bowlder 

Bowlder  gravel 

Bowlder  conglomerate 

256  mm. 

Cobble 

Cobble  gravel 

Cobble  conglomerate 

64  mm. 

Pebble 

Pebble  gravel 

Pebble  conglomerate 

4  mm. 

Granule 

Granule  gravel 

Granule  conglomerate 

2  mm. 

Very  coarse  sand  grain 

Very  coarse  sand 

Very  coarse  sandstone 

1  mm. 

Coarse  sand  grain 

Coarse  sand 

Coarse  sandstone 

1/2  mm. 

Medium  sand  grain 

Medium  sand 

Medium  sandstone 

1/4  mm. 

Fine  sand  grain 

Fine  sand 

Fine  sandstone 

1/8  mm. 

Very  line  sand  grain 

Very  fine  sand 

Very  fine  sandstone 

1/16  mm. 

Silt  particle 

Silt 

Siltstone 

1/256  mm. 

Clay  particle 

Clay 

Claystone 

MECHANICAL  ANALYSIS  OF  SEDIMENTS 


25 


fundamental  sexadecimal  ratio  and  combine  simplicity  in  visualiza- 
tion with  simplicity  of  computing  and  notation. 

The  best  compromise  at  present  possible  seems  to  be  the  use  of  the 
geometrical  ratio-scale  which  may  more  simply  be  designated  as  the 
1-2-4-8  mm.  scale.  The  engineer  scale  which  is  based  on  the  highly 
standardized  but  arbitrary  size  of  opening  in  the  200  mesh  sieve 
seems  to  the  writer  to  be  of  too  arbitrary  a  character  and  to  entail 
needless  complication  in  the  decimal  fractions  by  which  the  several 
limits  must  be  designated.  The  names  and  limits  of  the  several 
grades  established  by  the  1-2-4-8  mm.  scale  are  indicated  in  the  table 
below  previously  published  by  the  writer. 

Equipment 

The  following  outline  indicates  the  range  of  equipment  which  is 
convenient  in  analysing  sediments  of  sifting. 


Sieves  and  accessories 


Weighing  apparatus 


Handling  apparatus 


Fitted  sieves 

Covers 

Pans 

Blank  sieve  rings 

Wire  squares 

Mechanical  shaker 

Timing  clock 

Balance,  beam 
Balance,  portable  assay 
Balance,  spring 
Graduated  cylinder 

Bag  funnel  scoops 
Tube  funnel  trays 
Metal  pans 
Spoons 
Funnels 


Splitting  apparatus 


{Sample  splitter 
Scoop 
Pans,  square 


26 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Storage  accessories 


Washing  apparatus 


Cloth  bags 

Screw  top  glass  jars 

Metal  pill  boxes 

Glass  specimen  vials 

Corks 

Gummed  labels 

Tube  blocks 

f  Jars  and  cylinders 

Rubber  tubing 

Glass  tubing 
..Rising  current  washers 


{Brushes 
Squares  of  paper 
Rubber  stamps  for  notebook  tabulating 

Testing  sieves  consisting  of  woven  wire  cloth  soldered  into  sub- 
stantial stamped  brass  rings  may  be  had  from  a  number  of  makers. 
Some  of  these  makers19  are  in  a  position  to  furnish  sieves  with  open- 
ings conforming  very  closely  to  the  scale  here  recommended  when 
so  ordered.  These  sieves  are  made  so  as  to  fit  tightly  one  above  an- 
other and  are  available  in  several  diameters  and  heights.  The  writer 
has  found  that  two  sets,  an  eight  inch  series  running  from  64  to  2 
millimeters,  and  a  six  inch  series  running  from  1  to  1/16  millimeter 
are  convenient  since  it  is  rarely  desirable  to  run  the  analysis  of  a 
sediment  ranging  from  32  to  64  millimeters  down  to  1/8  mm.  or  less 
in  one  stage.  Another  set  of  six  inch  sieves  running  from  8  mm.  to 
1/16  mm.  is  convenient  for  those  samples  which  lie  in  this  range 
and  may  best  be  run  in  one  stage.  The  six  inch  sieves  are  quite 
large  enough  for  materials  under  1  millimeter.  In  traveling,  the 
individual  six  inch  sieves  can  be  packed  in  the  spaces  of  the  8  inch 
series  with  much  saving  of  space. 

A  pan  and  cover  are  essential  with  each  set  of  sieves  and  an  extra 
pan  or  two  are  very  convenient  when  handling  the  individual  separ- 
ates while  leaving  the  main  sieve  pile  standing  by.  Blank  sieve 
rings,  which  can  be  obtained  by  special  order  from  the  makers,  are 
useful  in  increasing  the  capacity  of  any  given  sieve  in  handling 
large  samples  of  the  coarser  gravels.    In  ordering  these  one  should 


19  Newark  Wire  Cloth  Co.,  Newark,  New  Jersey;  Multi  Metal  Co.,  799  East 
139th  St.,  New  York  City;  W.  S.  Tyler  Co.,  Cleveland,  Ohio. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  27 

specify  that  they  be  crimped  together  and  in  every  way  completely 
assembled  except  with  the  wire  cloth  left  out.  When  analysing 
sediments  containing  a  few  fragments  larger  than  the  largest  grade 
isolated  by  the  sieves,  several  large  wire  squares  conforming  to 
units  of  the  grade  scale  are  useful  in,  testing  these  large  pieces. 

If  large  numbers  of  analyses  are  to  be  made  a  mechanical  shaker 
is  almost  indispensable.  The  accuracy  of  separation  is  very  greatly 
increased,  results  are  standardized  to  a  degree  impossible  in  hand 
shaking,  and  very  heavy  samples  may  be  handled  in  one  stage  which 
in  hand  shaking  would  have  to  be  worked  through  grade  by  grade. 
With  an  automatic  timing  clock  such  an  instrument  accomplishes  in 
a  day's  time  shaking  which  would  take  at  least  a  week  by  hand 
methods  and  at  the  same  time  leaves  the  operator  free  to  perform 
the  weighing  and  other  operations  of  analysis.  Mechanical  shakers 
may  be  purchased  from  the  makers  or  may  be  constructed  in  any 
well  equipped  machine  shop.  A  shaker  should  be  so  designed  as  to 
combine  lateral  and  rotary  motions  with  rather  vigorous  jarring. 

The  balances  used  in  mechanical  analysis  should  be  of  the  sub- 
stantial laboratory  sorts  rather  than  precise  analytical  balances, 
since  convenience,  speed  of  operation  and  general  staunchness  are 
of  more  importance  than  great  accuracy.  Those  of  the  three  beam 
design  with  sliding  weights  by  which  the  tens,  units  and  fractions 
of  grams  are  determined  are  satisfactory.  Small  compact  portable 
assay  balances  are  convenient  for  field  use  with  small  samples  and 
spring  balances  have  been  used  by  the  author  in  field  analysis  of 
coarse  sediments.  In  working  with  rather  homogeneous  materials, 
such  as  sands  of  low  size  range  in  the  field,  it  is  probable  that  pro- 
portions could  be  determined  with  adequate  accuracy  by  volumetric 
means,  though  the  writer  does  not  know  that  this  method  has  been 
used  in  practice. 

If  much  analysis  is  to  be  carried  on  several  types  of  scoops  and 
funnels  will  be  found  useful  and  may  be  readily  made  by  any  sheet 
metal  worker.  The  funnel  scoop  shown  in  Fig.  1  is  convenient  in 
filling  bags  from  the  outcrop  or  from  sieves  or  pans.  Low-sided 
square  or  triangular  trays  slightly  larger  than  the  sieves  and  having 
one  open  corner  are  convenient  in  transferring  sand  grades  from 
the  sieves  to  the  glass  vials  in  which  they  are  stored.  An  assortment 
of  spoons  and  funnels  adds  to  the  convenience  of  handling. 

If  large  numbers  of  samples  are  to  be  analysed  they  are  handled 
most  expeditiously  by  separating  operations  and  several  must  be  at 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

various  stages  of  completion  in  the  laboratory  at  the  same  time.  In 
this  case  many  containers  will  be  needed  for  temporary  use.  Small 
metal  pill  boxes  are  useful  in  this  connection  and  for  the  larger  and 
coarser  separates  round  flat-bottomed  pudding  pans  or  basins  with 
flare  sides  are  recommended.  These  are  easily  cleaned,  will  with- 
stand the  moderate  heat  used  in  drying  sediments,  and  by  nesting 
many  of  them  may  be  stored  in  small  space  when  not  in  use. 

One  or  more  sample  splitters  will  be  needed  and  if  there  is  a 
great  range  in  the  coarseness  of  the  samples  handled  these  should 
be  of  both  large  and  small  sizes.  The  Jones  sampler  is  to  be  recom- 
mended or  for  combined  field  and  laboratory  use  a  folding  splitter 
based  on  the  same  principle  will  be  more  convenient.  A  number  of 
square  pans  should  be  provided  for  use  with  the  splitter. 

In  the  study  and  subsequent  storage  of  sediments  which  have 
been  mechanically  analysed  large  numbers  of  containers  are  needed. 
Since  many  of  the  materials  are  fine  grained  they  must  be  stored  in 
tighter  containers  than  are  needed  for  many  other  types  of  rock 
specimens  and  like  other  specimens  for  scientific  study  and  refer- 
ence, must  be  carefully  labelled.  If  permanent  storage  shelves  or 
cases  are  available  screw  top  glass  jars  are  the  most  satisfactory 
containers  for  the  larger  samples.  These  are  rather  expensive  in 
large  numbers  and  it  may  be  necessary  to  use  cloth  bags  for  these 
samples,  and  in  any  event  the  latter  are  preferable  for  field  collect- 
ing. Glass  shell  vials  are  convenient  and  inexpensive  for  storing 
samples  of  materials  not  coarser  than  8  mm.  up  to  25  or  50  grams 
in  amount.  These  may  be  had  in  various  sizes  and  are  closed  with 
short  corks  and  stored  vertically  in  holes  in  wood  blocks.  The 
writer  has  found  that  it  is  more  satisfactory  to  design  the  blocks 
and  case  drawers  so  that  a  certain  number  of  the  blocks  fit  in  each 
drawer  than  to  design  a  single  large  perforated  tube  holder  for  each 
drawer.  With  the  former  scheme  a  small  number  of  vials  together 
with  the  block  may  be  removed  for  inspection.  In  the  laboratory  at 
the  University  of  Iowa  each  block  accommodates  50  one-half  inch 
vials  in  5  rows  of  ten  each.  Each  drawer  of  a  case  accommodates 
eight  blocks  in  2  tiers  of  4  each,  thus  storing  a  total  of  400  tubes 
one-half  inch  in  diameter  and  twro  inches  long. 

In  washing  sediments  an  assortment  of  jars  and  cylinders  and 
glass  and  rubber  tubing  are  convenient.  In  a  laboratory  in  which 
much  mechanical  analysis  is  done  a  rising  current  washing  machine 
as  a  permanent  installation  will  save  the  labor  incident  to  rinsing 
the  various  sediments  by  hand  methods. 


MECHANICAL  ANALYSIS  OP  SEDIMENTS  29 

Several  brushes  with  soft  bristles  are  useful  in  transferring  fine 
sediments  from  one  container  to  another  and  may  sometimes  be  used 
in  cleaning  fine  sieves.  Squares  of  paper  of  several  sizes  will  be 
found  of  occasional  use  even  in  a  laboratory  well  equipped  with 
containers  of  various  sorts.  In  recording  the  results  of  analysis  a 
rubber  stamp  bearing  in  a  vertical  column  the  designations  of  the 
several  sieve  grades  is  convenient  in  blocking  out  the  entry  in  the 
notebook. 

Procedure 

In  describing  the  procedure  of  sifting  it  will  be  most  convenient 
to  follow  an  order  which  is  mainly  chronological,  starting  with  types 
of  analysis  of  coarse  sediments  which  are  sometimes  carried  out  in 
the  field  and  proceeding  thence  to  the  laboratory  technique. 

When  a  sample  of  coarse  material  ranging  to  64  mm.  or  more  and 
amounting  to  30  or  40  kilograms  has  been  collected  on  a  sampling 
cloth  and  is  not  needed  for  exhaustive  laboratory  study,  a  part  of 
the  analysis  may  well  be  accomplished  on  the  spot.  The  sample  is 
first  weighed  as  a  whole,  using  a  spring  balance  attached  to  the  four 
corners  of  the  cloth.  The  known  weight  of  the  cloth  should  be 
recorded  along  with  the  gross  weight.  Then,  working  on  the  cloth, 
all  pebbles  and  cobbles  over  a  convenient  sieve  size  should  be  separ- 
ated from  the  finer  material.  In  many  instances  this  separation 
can  be  accomplished  without  attempting  to  pass  all  the  material 
through  the  sieve  in  question  but  merely  working  through  the  ma- 
terial and  testing  doubtful  pieces  on  the  sieve.  The  coarser  frac- 
tion should  now  be  cleaned,  if  need  be  washed  and  dried,  run  through 
the  coarse  members  of  the  sieve  series  and  then  separates  weighed 
by  spring  balance  or  placed  in  bags  for  laboratory  weighing.  The 
material  washed  or  cleaned  from  these  fragments  may  be  discarded 
if  most  convenient  rather  than  added  to  the  fine  fraction.  If  de- 
sired, measurements  of  shape  and  notes  of  lithology  and  color  of 
the  larger  separated  cobbles  may  be  made  and  after  weighing  they 
may  be  discarded. 

The  fine  fraction  remaining  on  the  cloth  which  usually  amounts  to 
a  large  percentage  of  the  whole  sample  and  which  is  relatively  much 
more  homogeneous  than  the  original  sample,  may  now  be  quartered 
or  otherwise  split  down  to  a  sample  of  size  appropriate  to  the  coarse- 
ness of  the  larger  remaining  fragments.  If,  for  example,  the  4  mm. 
sieve  was  used  in  making  the  primary  separation  the  fine  fraction 
may  be  split  down  to  about  1  kilogram  and  the  remainder  rejected. 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  part  retained  will  be  weighed  and  analysed  in  the  laboratory. 
The  total  weight  of  the  fines  below  4  mm.  is  determined  as  the  differ- 
ence between  the  total  sample  and  the  total  of  the  cleaned  grades 
above  4  mm.  It  will  be  noted  that  the  only  operations  which  must 
be  carried  out  at  the  outcrop  are  the  weighing  of  the  total  sample, 
the  separation  of  the  sample  at  4  mm.  or  any  other  convenient  limit, 
and  the  splitting  of  the  fine  fraction  down  to  portable  size.  In  many 
instances  the  coarse  grades  will  not  be  of  great  weight  and  the  sam- 
ple will  be  reduced  in  weight  by  as  much  as  75  or  80  per  cent  by 
throwing  out  the  bulk  of  the  fine  fraction  in  the  manner  described. 
Furthermore,  in  order  to  do  this  no  more  equipment  is  needed  than 
a  single  sieve  or  in  a  pinch  a  single  accurate  wire  square. 

In  analysing  a  large  sample  of  coarse  sediment  in  the  laboratory, 
the  process  should  be  carried  on  in  stages  in  a  similar  fashion  to  the 
field  procedure.  If  the  material  is  fairly  dry  and  not  extensively 
aggregated,  the  2  mm.  sieve  may  be  made  the  separating  limit; 
otherwise  a  coarser  one  must  be  chosen.  The  entire  sample  is  poured 
on  the  pile  of  sieves  at  one  time  if  it  is  not  too  bulky.  There  may 
be  insufficient  room  in  the  pan  under  the  2  mm.  sieve  for  the  fine 
fraction,  in  which  case  this  will  need  to  be  successively  removed. 
Coarse  separates  which  are  too  large  in  bulk  for  one  sieve  space  may 
still  be  retained  by  adding  a  blank  sieve  ring  to  the  pile  at  the  pro- 
per place.  After  all  the  material  has  been  added  and  the  pile  has  been 
shaken  to  secure  a  rough  separation  into  grades  and  determine  the 
approximate  amounts,  it  is  ready  for  the  final  shaking  by  hand  or 
in  the  mechanical  shaker.  If  the  sample  is  dry  and  clean  enough 
so  that  practically  no  fines  will  remain  with  the  coarse  grades  as 
aggregates  or  incrustations,  the  whole  sample  need  not  be  weighed 
before  starting  the  analysis  but  in  most  cases  this  should  be  done. 

If  a  mechanical  shaker  is  available  the  shaking  may  be  very  quick- 
ly accomplished.  If  hand  shaking  is  necessary  the  separate  coarse 
grades  are  best  shaken  one  at  a  time,  using  a  cover  and  pan  with 
the  single  sieve  and  starting  with  the  coarsest  grade.  It  is  not 
practicable  to  establish  any  standard  time  of  hand  shaking  for  ma- 
terials of  this  sort.  With  a  sieve  containing  5  or  10  eight  to  sixteen 
millimeter  pebbles  the  completion  of  the  sifting  is  apparent  by  in- 
spection. As  one  proceeds  to  finer  grades  the  end  of  the  process  is 
less  sharp.  Since  the  condition  of  sediments  varies  so  greatly  the 
best  practice  seems  to  be  to  continue  shaking  until  the  amount  com- 


MECHANICAL  ANALYSIS  OP  SEDIMENTS  31 

ing  through  the  sieve  is  negligible  for  the  purpose  in  view.20  This 
is  best  determined  by  emptying'  or  changing  the  pan  after  the  major 
part  of  the  fines  has  come  through  and  shaking  successively  over  an 
empty  pan  for  a  number  of  equal  short  periods.  For  fine  sediments 
the  completion  of  the  sifting  process  is  a  practical  impossibility, 
either  by  hand  or  by  machine,  and  the  end  point  must  be  determined 
according  to  the  accuracy  desired.  The  writer  has  used  a  period  of 
5  minutes  for  machine  shaking  on  a  series  of  coarse  sediments  and 
achieved  a  satisfactory  separation  for  his  purpose.  The  subject  of 
accuracy  will  be  considered  more  at  length  in.  the  section  on  sources 
of  error  below. 

After  shaking,  the  coarse  grades  should  be  cleaned  and  weighed. 
The  fine  fraction  must  be  weighed  if  the  total  sample  weight  was 
not  determined  or  if  the  process  is  to  be  checked.  This  portion  is 
then  split  to  a  size  suitable  to  the  size  of  its  coarser  grades.  The 
analysis  of  a  part  of  the  fine  fraction  is  accomplished  in  a  manner 
similar  to  that  described  above.  The  principal  difference  is  that  in 
shaking  by  hand  a  larger  part  of  the  whole  shaking  may  be  done 
while  handling  the  entire  pile  of  sieves.  Any  sediment  in  which  a 
considerable  number  of  lumps  or  aggregates  withstand  the  shaking 
process  and  remain  with  coarser  grades  should  be  washed  or  other- 
wise disaggregated.  By  weighing  the  whole  sample  and  determin- 
ing total  fines  by  difference  the  more  troublesome  part  of  the  wash- 
ing process,  the  recovery  of  the  fines,  may  be  eliminated  provided  a 
small  fraction  is  retained  before  starting  the  washing  process. 

No  method  of  cleaning  sieves  is  known  which  is  rapid  and  ef- 
fective. Some  of  the  grains  may  be  removed  from  the  sieves  by  rub- 
bing from  the  bottom  side  with  a  cork.  Jarring  or  striking  the  ring 
with  the  hand  in  a  direction  diagonal  to  the  wires  will  dislodge 
some  but  not  all  of  the  grains.  A  stiff  brush  may  sometimes  be  used 
to  advantage.  Complete  cleaning  is  achieved  only  by  using  a  fine- 
pointed  implement  on  the  individual  grains  and  taking  care  not  to 
injure  or  displace  the  wires. 

In  making  critical  mineralogical  studies  the  best  procedure  ap- 
pears to  be  the  use  of  bolting  cloth  or  of  small  wire  sieves  such  as 
2  inches  in  diameter  which  one  may  keep  absolutely  clean  by  going 
over  each  sieve  with  a  pointed  tool. 

The  cleaned  separates  should  be  weighed  on  removal  from  the 

20  Goldman,  M.  I.,  Petrography  and  Genesis  of  the  Sediments  of  the  Upper 
Cretaceous  of  Maryland,  p.  121,  Baltimore,  1916. 


32  IOWA  STUDIES  IN  NATURAL  HISTORY 

sieves  and  then  rejected  or  stored  as  the  case  may  be.  In  general, 
weights  should  be  determined  to  the  order  of  the  nearest  1/1000  of 
the  whole  sample  analysed  in  the  given  stage.  For  very  careful 
work  in  checking  technique  or  with  very  homogeneous  material 
somewhat  more  accurate  weighing  is  desirable. 

The  amount  of  material  needed  for  most  satisfactory  analysis 
varies  somewhat  with  the  composition  of  the  material  as  well  as 
with  the  coarseness.  The  amounts  indicated  in  the  last  column  of 
the  table  on  page  10  are  minimum  amounts  for  material  down  to 
about  8  mm.  Below  that  limit  the  amounts  most  convenient  for 
analysis  are  shown  in  column  2  of  the  table.  It  may  be  suggested 
in  general  that  the  material  lodging  in  any  one  sieve  should  be  small 
enough  in  amount  so  that  at  least  half  the  sieve  surface  is  free  at 
the  end  of  each  shaking  oscillation.  Sifting  is  a  very  slow  and 
probably  much  less  accurate  process  when  the  material  on  a  sieve 
covers  it  deeply  throughout  the  shaking. 

The  annotated  computation  outlines  given  below  in  the  section  on 
computing  and  plotting  will  serve  as  tabular  summaries  of  the 
analysis  procedure  under  several  different  conditions. 

Sources  of  Error 
A  mechanical  analysis  is  a  means  of  determining  the  mechanical 
composition  of  all  or  part  of  a  sedimentary  deposit.  If  the  com- 
position shown  by  the  analysis  is  not  identical  with  that  of  the 
deposit  the  analysis  is  in  error  by  the  difference.  The  composition 
shown  by  analysis  may  be  accurate  as  representing  the  sample  from 
which  it  was  made  and  still  very  inaccurate  as  representing  the 
deposit  from  which  the  sample  came.  A  tabular  synopsis  of  the 
various  sources  of  error  in  mechanical  analysis  is  given  below. 
Errors  resulting  from  the  geologist's  inability  to  locate  the  sample 
properly  are  probably  large.  Especially  if  the  sample  is  taken  for 
the  purpose  of  representing  the  typical  composition  of  a  deposit, 
it  is  likely  to  fall  short  of  its  purpose.  The  writer  believes  that 
there  is  a  strong  tendency  in  attempting  to  collect  a  typical  speci- 
men to  collect  what  is  more  properly  an  ideal  specimen.  Other  er- 
rors of  the  collecting  process  can  be  largely  reduced  by  care  in  the 
technique.  It  is  believed  that  with  the  present  excellence  of  woven 
wire  cloth  errors  due  to  variations  in  sieve  openings  from  uniform- 
ity or  from  the  ratings  of  the  makers  are  relatively  small  and  neg- 
ligible compared  to  the  errors  arising  from  the  inability  of  the 
geologist  to  collect,  even  from  the  same  outcrop  at  different  times, 


MECHANICAL  ANALYSIS  OF  SEDIMENTS 


33 


two  identical  samples.  Elaborate  tests  of  the  performance  of  a 
series  of  sieves  made  by  a  reliable  maker  do  not  seem  to  the  writer 
to  be  crucial  in  assuring  the  reliability  of  analyses  made  thereby 
when  so  much  larger  errors  almost  without  exception  are  present  as 

ERRORS  IN  MECHANICAL  ANALYSIS 


Source 

Result 

c 

0 
L 
L 
E 
C 
T 
I 
N 
G 

Sample  not  well  located. 
Sample  too  small. 
Outcrop  not  well  cleaned. 

Selective  accidental  loss  in  col- 
lecting. 

Subsequent  loss  from  contain- 
er. 

General  error. 

Large  errors  in  coarse  grades. 

Increase    in    either    fine    or 

coarse  grades. 
Decrease    in    either    fine    or 

coarse  grades. 
Decrease    in     either    fine    or 

coarse  grades. 

P 
R 
E 
P 
A 
R 
A 
T 
I 
O 
N 

Unsound  splitting  method. 
Faulty  splitting  practice. 
Splitting  to  too  small  fraction. 

Loss  of  fine  grades  on  cloth  or 
from  blowing. 

Error  in  assumption  that  fine 
grades  washed  from  aggre- 
gates are  normal. 

Increase     in     either     fine     or 

coarse  grades. 
Increase    in     either     fine    or 

coarse  grades. 
Large  errors  in  coarse  grades. 

Decrease  in  fine  grades. 

Probable    decrease    in    finest 
grades  with  increase  in  in- 
termediate. 

A 

N 
A 
L 
Y 

S 

I 

s 

Errors  in  sieve  opening   rat- 
ings. 
Nonuniform  sieve  openings. 
Incomplete  shaking. 

Loss  of  fine  grades  by  lodge- 
ment in  sieves  or  elsewhere. 
Errors  in  weighing. 

Local  errors  between  grades. 

Local  errors  between  grades. 
General  increase  in  coarseness 

indicated 
Decrease  in  finest  grades. 

Local  large  error,  small  gen- 
eral error. 

Computation 

and 

Plotting 

Errors  due  to  use  of  slide  rule. 
Errors  in  plotting. 

Small  local  errors. 
Small  local  errors. 

a  result  of  unknown  infelicity  in  the  choice  of  the  sample.  In  the 
case  of  the  standardization  of  the  200  mesh  sieve  for  engineering 
specifications  the  situation  is  quite  different  for  here  a  highly  uni- 
form artificial  material  is  being  handled  of  which  the  mechanical 
composition  as  delivered  is  critical. 

There  is  another  viewpoint  in  considering  the  accuracy  of  me- 
chanical analyses.  The  means  of  interpreting  mechanical  analyses 
do  not  seem  likely  in  the  near  future  to  reach  an  excellence  capable 


34 


IOWA  STUDIES  IN  NATURAL  HISTORY 


of  taking  account  of  very  small  differences  in  mechanical  composi- 
tion. For  purposes  of  interpretation  the  writer  believes  that  errors 
in  any  grade  amounting  to  less  than  1/4  per  cent  of  the  whole  sam- 
ple times  the  square  root  of  the  percent  of  the  grade  (an  arbitrary 
rule)  may  be  regarded  as  negligible.  Figure  2  shows  the  plotted 
pyramids  for  two  analyses  differing  within  this  range.  In  a  two- 
grade  analysis  if  differences  less  than  the  amount  stated  are  eon- 


Vsfr'/eV*  mm. 


Yz'/fyaV*  "»». 


Fig.  2.     Composition  pyramids  or  histograms  of  two  analyses  differing 
by  the  limits  described  above. 

sidered  negligible  there  are  still  approximately  100  types  of  com- 
position possible,  disregarding  those  where  one  grade  is  less  than  1 
per  cent.  Similarly  in  a  three-grade  analysis  there  are  approximate- 
ly 5,000  types  and  in  a  four-grade  analysis  are  well  over  150,000 
possible  types  of  mechanical  composition  of  which  a  large  fraction 
would  be  likely  to  occur  in  natural  sediments. 

The  writer  does  not  wish  to  advise  against  improvement  of  the 
accuracy  of  the  sifting  operation  of  mechanical  analysis  but  he  be- 
lieves that  the  results  at  present  attainable  with  reasonable  care  in 
the  technique  are  so  much  in  advance  of  the  reliability  of  the  col- 
lected samples  and  in  advance  of  present  methods  of  interpreting 
the  analyses  after  they  have  been  made  that  the  principal  emphasis 
in  making  for  improvement  should  be  placed  at  the  two  last  named 


MECHANICAL  ANALYSIS  QF  SEDIMENTS  35 

points.  It  seems,  for  example,  that  it  would  be  much  more  profit- 
able to  collect  and  analyse  in  a  fairly  accurate  and  expeditious 
fashion  100  samples,  computing  the  results  by  slide  rule  and  pre- 
senting them  in  graphic  form  than  to  spend  the  same  time  on  25 
samples,  running  analyses  in  duplicate,  weighing  to  one  more  place 
of  decimals  and  presenting  the  results  to  hundredths  rather  than 
tenths  of  a  per  cent. 

ANALYSIS  BY  COUNTING 

General  Statement 
Under  this  heading  are  considered  a  number  of  methods  which 
have  in  common  the  feature  that  the  size  of  each  fragment  is  de- 
termined by  some  sort  of  direct  measurement.  None  of  these  methods 
may  be  considered  preferable  to  the  method  of  screening  when  the 
proper  equipment  for  the  latter  is  available  and  it  can  be  applied, 
but  are  rather  to  be  regarded  as  supplementary  under  exceptional 
conditions  as  applying  to  sediments  beyond  the  range  of  screening. 

Estimating  Composition  in  the  Outcrop 
It  is  sometimes  desirable  to  make  an  estimate  of  the  relative 
abundance  of  boulders  of  different  sizes  in  a  coarse  gravel  or  till 
and  such  is  essentially  an  estimate  of  mechanical  composition.  It 
is  sometimes  possible  to  accomplish  this  by  measuring  the  boulders 
in  the  reject  pile  of  a  commercial  gravel  pit  where  the  large  boulders 
encountered  in  working  a  known  volume  of  gravel  have  been,  piled 
at  one  side  to  get  them  out  of  the  way.  More  commonly  such  an 
estimate  must  be  made  from  the  outcrop  and  in  such  a  case  a  large, 
fairly  plane  exposure  normal  to  the  bedding  is  most  suitable.  The 
procedure  used  by  the  writer  is  to  select  in  the  given  outcrop  a 
series  of  cobbles  and  boulders  as  reference  sizes,  one  for  each  grade. 
These  may  be  chosen  to  represent  the  mean  size  of  the  grade  such 
as  the  series  90,  180,  360,  720,  1440  millimeters,21  or  the  limiting 
sizes  of  64,  128,  256,  512,  1024  millimeters.  They  should  be  chosen 
by  actual  measurement  to  conform  as  closely  as  possible  to  the 
square  mesh  sieve  series.  After  marking  these  with  chalk  or  other- 
wise the  estimate  should  be  made  by  standing  well  back  from  the 
outcrop  and  counting  all  those  cobbles  and  boulders  which  appear  to 
belong  to  each  grade.  In  making  use  of  such  a  count  several  princi- 
ples should  be  borne  in  mind.    First,  the  apparent  size  as  protrud- 

2i  Consisting  of  the  series  64,  128,  256,  etc.  multiplied  by  V2  respectively. 


36  IOWA  STUDIES  IN  NATURAL  HISTORY 

ing  from  the  outcrop  is  not  the  real  size,  being  often  smaller  and  in 
fewer  instances  (case  of  a  broadside  view  of  an  elongate  boulder), 
being  larger.  Second,  the  larger  boulders  wThich  appear  in  the  out- 
crop represent  a  much  larger  volume  of  the  material  than  do  the 
smaller  cobbles  which  appear  in  the  same  outcrop.  The  first  princi- 
ple named  probably  does  not  introduce  errors  which  would  be  re- 
garded as  large  in  an  estimate  of  this  kind  since  the  general  con- 
vexity of  the  exposed  portion  of  the  boulder  will  enable  the  observer 
on  the  average  to  place  a  given  boulder  in  the  correct  grade  even 
though  the  area  exposed  is  much  less  than  the  true  cross-section.  The 
second  principle  must  be  considered  more  in  detail.  An  adequate 
theoretical  study  of  the  relative  probability  of  retention  in  the  out- 
crop of  large  and  of  small  boulders  would  be  extremely  complicated 
and  the  factors  involved  would  have  different  values  for  a  host  of 
different  rocks.  For  the  present  purpose  it  will  suffice  to  eliminate 
a  number  of  these  by  assuming  a  similar  behavior  for  large  and  for 
small  boulders.  For  example,  any  boulder  may  be  said  to  be  repre- 
sented in  the  outcrop  if,  protruding  sufficiently  from  the  outcrop  to 
be  recognized  as  belonging  to  its  proper  grade,  it  is  still  well  enough 
supported  and  held  to  remain  in  place.  Similar  retention  in  large 
and  small  boulders  may  be  defined  as  the  condition  when  the  range 
of  retention  from  a  given  percentage  of  linear  protrusion  needed 
for  recognition  to  the  larger  percentage  of  linear  protrusion  when 
the  boulder  falls  is  a  constant  fraction  of  the  average  diameter  of 
the  boulder  regardless  of  its  absolute  size.  If  this  be  the  case  then 
the  boulders  of  several  grades  which  are  present  in  the  outcrop 
represent  volumes  of  material  which  stand  in  the  ratio  of  the  linear 
dimensions  of  the  several  grades.  This  approximate  assumption 
will  be  made  clear  by  reference  to  the  following  computation  sched- 
ule. 

In  using  this  method  of  estimate  the  results  obtained  by  methods 
so  far  described  are  relative  and  some  absolute  measure  must  be  had 
to  permit  expression  as  a  partial  mechanical  analysis.  Perhaps  the 
best  method  of  securing  this  is  by  estimating  the  linear  thickness  of 
the  zone  of  retention  for  one  of  the  coarser  grades  by  inspection.  A 
grade  in  which  there  are  a  number  of  boulders  should  be  used  rather 
than  to  use  very  few  boulders  of  extreme  size.  This  measure  times 
the  length  and  height  of  the  exposure  will  give  the  volume  of  which 
the  number  of  boulders  of  the  grade  in  question  are  a  proper  part 


MECHANICAL  ANALYSIS  OP  SEDIMENTS  37 

and  the  volumes  for  the  other  grades  are  scaled  from  this,  using  the 
proportion  principle  stated  above. 

This  method  is,  of  course,  not  a  quantitative  one  in  the  strict 
sense,  yet  it  is  believed  that  the  present  proper  trend  in  geology  is 
toward  quantitative  points  of  view  and  methods  of  expression  and 
that  estimates  of  this  sort  are  of  much  value  when  undertaken  by 

TABLE  SHOWING  REDUCTION  OF  FIELD  DATA  IN  ANALYSIS  BY 
COUNTING  AT  THE  OUTCROP22 

Grade  sizes        Number  of        Number  in  unit        Total  volume        Per  cent 
pieces volume of  graders of  total 


512-256  mm. 

3 

3 

12188 

7.4 

256-128  mm. 

18 

36 

18432 

11.1 

128-  64  mm. 

29 

112 

7168 

4.4 

64-  32  mm. 

15 

120 

960 

.6 

32-  16  mm. 

21 

336 

336 

.2 

39084 

23.7 

a  competent  observer  who  has  the  necessary  theoretical  principles  in 
mind  when  making  the  observations  and  making  the  subsequent 
computation. 

Measurements  op  Three  Diameters 
Measurements  of  three  diameters  are  sometimes  made  in  the  course 
of  studies  of  roundness  or  other  shape  characteristics  and  may  be  of 
subsequent  value  in  separating  the  pebbles  or  cobbles  into  grades. 
In  doing  this  the  average  diameter  may  be  used  for  compact  nearly 
equidimensional  fragments,  but  use  of  the  small  cross-section  (lesser 
times  intermediate  diameter)  is  more  accurate  for  elongate  forms. 


22  Values  in  column  3  are  obtained  from  those  in  column  2  by  multiplying 
by  the  multiples  of  2  starting  from  the  top,  i.e.,  1,  2,  4,  etc.  Column  4  is  de- 
rived from  column  3  by  multiplying  by  cubes  of  the  powers  of  2 ;  i.e.,  1,  8,  64, 
512,  etc. 

23  Units  are  volumes  of  mean  pieces  of  32-16  mm.  grade  or 

( 3 

16  (1.414)       x  3.1416  =  6,066  cu.  mm. 

6 

Unit  volume  is  in  this  case  an  area  of  three  square  meters  to  a  depth  assumed 
as  approximately  the  mean  diameter  of  pieces  of  the  larger  grade;  i.e.,  35  cm. 
or  practically  1/3  meter.  The  volume  of  the  grades  estimated  is  the  product 
of  6,066  cu.  mm.  by  the  total  of  column  four  and  is  .237  cubic  meters  or  23.7 
per  cent  of  the  whole.  The  cmoposition  of  the  remaining  76.3  per  cent  must  be 
determined  by  sieve  analysis  of  a  sample  of  the  minus  16  mm.  matrix. 


38  IOWA  STUDIES  IN  NATURAL  HISTORY 

Analysis  by  Weight 
The  cobbles  and  pebbles  of  a  coarse  sample  may  be  sorted  into 
grades  on  the  basis  of  weight  fairly  rapidly  by  using  a  spring  bal- 
ance and  pan.  After  determining  the  grade  limits  by  weight  a 
paper  scale  having  only  three  grade  limits  marked  in  strong  lines 
may  be  attached  to  the  face  of  the  balance.  Speed  is  increased  by 
making  a  preliminary  rough  sorting  by  inspection,  thus  permitting 
the  weighing  of  like  sizes  in  close  succession.  If  the  range  is  great 
two  or  more  balances  of  different  capacities  will  be  needed. 

Microscopic  Counting 
The  writer  has  had  but  limited  experience  in  this  type  of  mechan- 
ical analysis.    Certain  points  in  this  limited  experience  seem  worthy 
of  mention.     Counting  is  best  done  on  a  ruled  surface  or  using  a 
ruled  eyepiece.    For  material  over  about  1/8  mm.  paper  ruled  in 
millimeters  has  been  used  to  good  advantage  as  a  background.    Fine 
ruled  gratings  on  glass  for  use  on  the  microscope  stage  may  be  had 
of  dealers  in  accessories.    Eyepiece  gratings  have  the  disadvantage 
that  they  do  not  commonly  conform  to  the  grades  used  and  if  one  is 
provided  for  use  with  one  objective  it  will  be  of  odd  size  if  used  with 
another.    To  get  around  various  of  these  difficulties  the  following 
method  is  suggested.    All  microscope  fields  which  are  to  be  analysed 
are  projected  onto  a  frosted  or  ground  glass  surface  above  the 
microscope  in  the  manner  used  for  photomicrography.    On  this  sur- 
face are  drawn  permanently  the  lines  of  a  grating  of  appropriate 
size.    By  changing  the  distance  of  projection  and  the  objectives  it  is 
practicable  to  enlarge  grains  of  sediment  of  all  grades  to  a  standard 
image  size  and  make  all  counts  on  the  ground  glass  at  this  size, 
which  can  be  large  enough  to  greatly  reduce  eye  fatigue.    By  the 
use  of  ordinary  camera  lenses  as  well  as  microscope  objectives,  all 
grades,  even  those  which  are  readily  estimated  by  direct  inspection, 
may  be  projected  to  a  standard  image  size,  the  larger  fragments  be- 
ing reduced.     Thus  a  whole  sample  may  be  subjected  to  the  same 
technique  and  the  inevitable  break  which  would  attend  errors  of 
judgment  if  the  work  were  partly  megascopic  and  partly  micro- 
scopic is  eliminated.    Another  advantage  of  this  method  is  that  the 
grains  counted  may  be  checked  off  on  the  ground  glass  with  a  pencil 
thus  lightening  the  fatigue  of  sustained  attention  in  ordinary  micro- 
scopic counting. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  39 

ANALYSIS  BY  ELUTRIATION 
Foreword 
In  the  first  outline  of  this  paper  it  was  intended  that  the  analysis 
of  fine  sediments  by  elutriation  should  be  treated  at  length.  Progress 
of  the  work  showed  the  inadvisability  of  attempting  a  detailed 
treatment  at  this  time  and  the  following  brief  outline  is  here  pre- 
sented as  a  supplement  to  the  methods  applicable  to  coarse  sedi- 
ments. 

Outline  of  Methods 
By  some  students  the  term  elutriation  is  confined  to  separation  of 
grains  in  a  rising  current  apparatus,  but  by  others  it  is  also  applied 
to  separation  by  settling  in  a  static  column.  The  writer  prefers  the 
latter  usage.  Apparatus  for  elutriation  has  been  described  by  a 
number  of  investigators  and  these  descriptions  need  not  be  presented 
here.    Four  principal  types  may  be  recognized  as  follows : 

1.  Jars  and  cylinders  for  simple  decantation.24 

2.  Simple  tubes  for  rising  current  separation.25 

3.  Multiple  tube  series  for  rising  current  separation.26 

4.  Recording  subsidence  machines  of  the  Oden  type.27 

Each  type  has  points  of  merit.  The  simple  decantation  jars  and 
cylinders  are  simple  and  easy  to  operate  and  with  repeated  washing 
results  are  as  accurate  as  those  derived  by  any  other  technique. 
Need  for  repeated  washing  is  eliminated  in  the  continuous  current 
devices  (2  and  3).  In  the  Oden  machine  the  true  composition  curve 
is  deduced  by  mathematical  analysis  of  the  curve  of  settling.  The 
continuous  current  devices  have  the  disadvantage  that  the  axial 
velocity  and  marginal  velocity  in  the  tube  differ  greatly  and  the 
exact  conditions  of  separation  at  different  temperatures  are  not 
known.  The  principal  disadvantages  of  the  Oden  machine,  as  they 
appear  to  the  writer,  are  the  expense  of  construction  and  installation 
and  the  labor  of  computing  results. 


24  Goldman,  M.  I.,  Petrography  and  Genesis  of  the  Sediments  of  the  Upper 
Cretaceous  of  Maryland,  pp.  169-170,  Baltimore,  1916. 

25  Holmes,  A.,  Petrographic  Methods  and  Calculations,  p.  215,  London,  1921. 
2«  Holmes,  A.,  Op.  tit.,  p.  209. 

Hatch,  F.  H.,  &  Rastall,  B.  H.,  Textbook  of  Petrology,  The  Sedimentary 
Rocks,  pp.  342-357,  London,  1913. 

Cayeux,  L.,  Op.  tit.,  pp.  36-45,  1916. 

27  Oden,  Sven,  Studien  uber  Tone,  2,  Automatisch  registrierbare  Methode  zur 
mechanischen  Bodenanalyse,  Bull.  Geol.  Inst.  Univ.  of  Upsala,  pp.  15-64,  Up- 
sala,  1919. 


40  IOWA  STUDIES  IN  NATURAL  HISTORY 

Grade  Scales 

All  methods  of  elutriation  involve  the  problem  of  hydraulic  values 
of  particles  of  varying  size,  shape  and  density  at  various  tempera- 
tures. This  problem  has  been  approached  by  many  investigators 
but  no  adequate  determinations  have  been  made  of  the  effects  of 
shapes  of  particles  in  modifying  their  velocity  of  fall  through 
water.28  Data  given  by  different  students  show  large  variation.29 
Theoretical  values,  according  to  Stokes  law,  differ  from  any  of  the 
empirical  values.  Theoretical  hydraulic  values  for  spheres  follow 
two  different  laws  for  large  and  for  small  particles.  Large  particles 
fall  in  water  with  velocities  proportional  to  the  square  root  of  the 
diameter.  Small  particles  fall  with  velocities  proportional  to  the 
square  of  the  diameter.  (Stokes  law.)  Both  rates  depend  on  cer- 
tain constants  derived  from  the  densities  of  water  and  the  particle 
and  the  viscosity  of  water  at  the  temperature  in  question.  In  the 
case  of  large  particles  viscosity  is  negligible ;  in  that  of  small  parti- 
cles inertia  becomes  negligible.  In  the  zone  between  1.55  mm.  and 
0.2  mm.30  for  particles  of  the  density  of  quartz  both  factors  are  im- 
portant and  the  velocities  undergo  a  transition  from  those  of  the 
square  root  law  to  those  of  the  square  law.31 

In  the  case  of  a  study  of  silts  and  clays  in  which  the  entire  sam- 
ple can  be  separated  by  elutriation,  the  grades  may  best  be  desig- 
nated by  the  limiting  falling  velocities  in  millimeters  per  second, 
using  a  uniform  ratio  series  like  the  powers  of  2  or  3.  The  deter- 
mined or  supposed  sizes  of  particles  can  be  given  as  supplementary 
data.  In  many  studies,  however,  the  elutriation  scale  must  be  joined 
to  the  sieve  scale  and  should  have  nearly  the  same  size  ratios  be- 
tween the  grade  limits  as  the  latter.  In  his  study  of  coastal  plain 
gravels  the  writer  used  the  following  assumed  hydraulic  values  for 
the  continuation  of  the  sieve  grades : 


28  Richards,  R.  H.,  Textbook  of  Ore  Dressing,  p.  264,  New  York,  1909. 

29  Richards,  R.  H.,  Op.  cit.,  pp.  262-268. 
Holmes,  A.,  Op.  cit.,  p.  207. 

Moles,  E.  C.  Jul.,  Bulletin  du  Department  de  V  Agriculture  aux  Indes  Neer- 
landaises,  Buitenzorg,  1910,  pp.  7-15. 

so  These  values  are  given  by  Richards,  Op.  tit.,  pp.  262-268,  and  by  Holmes, 
Op.  tit.,  p.  206. 

31  This  subject  is  briefly  and  cogently  discussed  by  Richards,  Op.  tit.,  pp.  262- 
268. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS 


41 


Diameter 

Millimeters 

per  second 

1/16 

4 

1/32 

4/3 

1/64 

4/9 

1/128 

4/27 

This  scale  has  no  precise  theoretical  justification  but  is  a  simple  and 
easily  remembered  scale  closely  approximating  the  mean  of  several 
published  tables  by  hydraulic  values  throughout  its  range. 

Procedure 
The  general  plan  of  elutriation  by  settling  consists  of  allowing 
the  particles  to  settle  for  a  fixed  period  of  time  from  a  thoroughly 
mixed  turbid  suspension ;  at  the  end  of  that  time  the  water  and  those 
particles  not  settled  are  drawn  off  as  rapidly  as  possible  with  a 
syphon  of  glass  or  rubber  tube.  The  settled  portion  is  remixed  with 
fresh  water  and  the  operation  repeated.  It  is  apparent  that  while  all 
the  larger  particles  are  settling  from  the  top  of  the  column  that  a 
half  of  those  particles  which  settle  only  half  as  rapidly  will  settle 
out  of  the  lower  part  of  the  column;  i.e.,  all  of  these  contained  in 
the  lower  half  column.  If  the  grade  scale  be  built  on  the  ratio  3  in 
hydraulic  values  instead  of  2,  the  progress  of  separation  by  settling 
will  be  shown  on  the  following  table. 

TABUS  SHOWING  PROGRESS  OF  REMOVAL  OF  FINER  GRADES  BY 

WASHING32 


Grade  limits 

mm.  per 

second 

Mean  hydrau- 
lic value  mm. 
per  second 

Per  cent  of  grade  present 

After  1st. 
washing 

After  2nd. 
washing 

After  3rd 
washing 

After  4th 
washing 

27 

100 

100 

100 

100 

15.6 

58 

33 

19 

11 

9 

33 

11 

3.7 

1.2 

15.2 

19 

3.7 

.7 

.1 

3 

11 

1.2 

.1 

1.7 

6.3 

A 

1 

3.7 

.1 

From  the  table  it  appears  that  after  four  washings  of  grade 
81-27  mm.  per  second  there  will  remain  about  11  per  cent  of  grains 

82  Time  of  settling  just  permitting  grains  of  value  27  to  faU  from  top. 


42  IOWA  STUDIES  IN  NATURAL  HISTOEY 

of  mean  size  in  the  27-9  mm.  per  second  grade,  only  1.2  per  cent  of 
the  smallest  grains  but  approaching  100  per  cent  of  the  largest 
grains.  It  is  evident  that  complete  removal  of  grains  just  under 
the  lower  limit  of  the  grade  being  washed  is  not  practicable  and 
some  slight  contamination  by  these  remains  even  after  many  wash- 
ings. In  most  work  three  or  four  washings  must  suffice.  Correc- 
tions based  on  the  principle  of  the  table  above  may  be  applied  if  the 
need  justifies  and  manipulations  have  been  sufficiently  precise. 

In  the  rising  current  type  of  elutriation  a  few  minutes  of  opera- 
tion will  do  the  work  of  many  washings,  but  here  also  the  removal 
of  grains  just  below  the  lower  size  limit  of  the  grading  being  washed 
is  relatively  slow.  The  writer  is  not  aware  that  rising  current 
elutriations  have  been  devised  for  very  low  velocities,  such  as  those 
below  1/50  mm.  per  second  except  as  attempted  in  the  Yoder  centri- 
fugal elutriator. 

Deflocculation33 

In  analysing  clays,  important  difficulties  arise  because  of  the 
presence  of  materials  having  colloidal  properties  and  capable  of 
forming  aggregates  under  varying  electrolytic  conditions.  In  all 
analyses  by  elutriation  it  is  desirable  to  use  distilled  water  and  re- 
duce error  due  to  flocculation  to  as  low  a  value  as  possible.  Water 
from  condensed  steam  in  a  heating  system  or  rain  water  is  prefer- 
able to  tap  water  where  distilled  water  in  the  necessary  quantities  is 
not  available.  In  analysing  most  clays  treatment  for  deflocculation 
is  necessary.  For  a  description  of  methods  the  reader  is  referred 
to  the  work  of  Goldman,34  Milner,35  and  Steiger.36 

Clays  differ  so  widely  one  from  another  that  it  is  difficult  to  give 
precise  directions  applicable  to  all.  Probably  the  best  general  pro- 
cedure is  a  deflocculation  by  shaking  in  a  solution  of  sodium  carbon- 
ate or  ammonia  and  suspension  for  elutriation  in  a  similar  weakly 
alkaline  solution.  It  is  to  be  borne  in  mind  that  electrical  energy 
must  be  supplied  to  bring  about  the  electrical  neutralization  of  the 


ss  In  writing  and  revising  this  section  the  writer  has  had  the  benefit  of  val- 
uable suggestions  and  advice  from  M.  S.  Littlefleld,  of  the  University  of  Iowa, 
M.  I.  Goldman,  of  the  U.  S.  Geol.  Survey,  and  R.  O.  E.  Davis,  of  the  U.  S. 
Bureau  of  Soils. 

34  Goldman,  M.  I.,  The  Petrography  and  Genesis  of  the  Sediments  of  the  Up- 
per Cretaceous  of  Maryland,  pp.  115-119,  Johns  Hopkins  Univ.  Press,  1916. 

ss  Milner,  H.  B.,  An  Introduction  to  Sedimentary  Petrography,  p.  24,  London, 
1922. 

3«  Steiger,  Geo.,  Treatise  on  Sedimentation,  Edited  by  W.  H.  Twenhof  el,  pp. 
630-631,  Baltimore,  1926.  See  also  U.  S.  Bureau  of  Soils,  Bulletins  24  and  84. 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  43 

aggregated  clay  particles  and  effect  deflocculation,  and  also  that 
though  the  sizes  of  the  aggregates  may  be  materially  reduced  by 
such  treatment  complete  deflocculation  such  that  each  subsiding 
particle  is  a  single  mineral  grain  is  essentially  impossible  except  by 
a  precise  treatment  worked  out  by  the  student  with  particular  refer- 
ence to  the  physical  and  chemical  condition  of  the  sample  in  hand. 

It  is  further  necessary  to  emphasize  that  since  all  natural  clays 
consist  largely  of  colloidal  material  in  varying  degrees  of  floccula- 
tion  and  were  such  at  the  time  of  accumulation,  it  is  futile  to  hope 
in  most  cases  that  conditions  closely  approaching  those  obtaining  at 
the  time  of  deposition  can  be  set  up  by  treatment  for  deflocculation 
or  that  the  size  distribution  as  determined  by  hydraulic  methods 
can  be  used  in  the  interpretation  of  the  aqueous  conditions  of  origin 
with  confidence  in  those  sediments  fine  enough  to  be  materially  af- 
fected by  colloidal  phenomena.  The  writer  does  not  wish  to  convey 
the  idea  that  it  is  useless  to  attempt  to  analyse  fine  grained  sedi- 
ments, but  he  does  wish  to  emphasize  the  view  that  results  obtained 
by  a  routine  application  of  any  single  procedure  to  a  variety  of 
sediments  are  not  likely  to  be  of  great  significance  or  value  in  inter- 
preting the  origin  of  the  material  in  question.  It  should  be  borne 
in  mind  that  some  sediments  may  have  been  in  a  highly  flocculated 
condition  at  the  time  of  deposition  and  that  to  attempt  complete 
deflocculation  as  a  general  goal  is  as  pernicious  as  the  analysis  of 
sediments  without  any  deflocculation  procedure.37  It  is  to  be  hoped 
rather  that  each  student  will  endeavor,  by  a  study  of  the  behavior 
of  the  sediment  in  hand  under  various  electrolytic  conditions  and 
by  a  study  of  resulting  particles  under  the  microscope,  to  learn  the 
nature  of  the  existing  state  of  aggregation  and  to  adapt  his  treat- 
ment for  deflocculation  so  as  to  convert  the  sediment  most  nearly 
into  a  significant  previous  condition  of  aggregation  whether  that 
requires  complete  deflocculation,  or  very  little,  or  none  at  all. 

COMPUTING  AND  PLOTTING 

Methods  of  Computing 

The  computing  involved  in  mechanical  analysis  consists  for  the 

most  part  of  simple  percentage  arithmetic.     For  most  purposes  it 

can  be  carried  out  with  sufficient  accuracy  by  means  of  a  ten-inch 

slide  rule.    When  a  sample  has  been  analysed  in  one  stage  it  is  com- 


37  Davis,  R.  O.  E.,  The  Interpretation  of  Mechanical  Analysis  of  Soils  as 
affected  by  Soil  Colloids,  Jour.  Amer.  Soc.  Agronomy,  Vol.  14,  pp.  296-297,  1922. 


44  IOWA  STUDIES  IN  NATURAL  HISTORY 

monly  the  case  that  the  total  of  the  separate  weights  is  slightly  less 
than  the  weight  of  the  total  sample  before  analysis.  With  reason- 
able care  the  discrepancy  can  be  kept  down  to  a  fraction  of  one  per 
cent,  even  on  light  samples  of  but  a  few  grams.  The  loss  may  be 
from  any  of  the  grades  by  lodgement  in  the  sieves  or  otherwise.  It 
is  the  custom  among  some  workers  to  consider  that  the  entire  loss  is 
from  the  fine  grade.  Unless  this  has  been  proven  to  be  the  case  by 
careful  tests,  it  seems  better  as  a  general  practice  to  distribute  the 
error  among  all  the  grades.  This  is  accomplished  by  using  the 
total  resulting  by  addition  of  the  separate  weights  rather  than  the 
original  one. 

In  computing  the  percentages  by  slide  rule  slight  errors  of 
manipulation  and  reading  will  enter,  causing  the  total  of  the  per- 
centages to  add  to  less  or  more  than  100.  Here  the  discrepancy 
need  be  no  more  than  one  or  two  tenths  of  one  per  cent  and  it  is  the 
writer's  custom  to  compute  the  largest  percentage  last  and  by  add- 
ing the  column  of  tenths  of  the  other  percentages  determine  the 
proper  digit  to  be  read  in  the  tenths  of  the  last  and  largest  percent- 
age. This  should  rarely  differ  from  that  actually  appearing  on  the 
rule  by  more  than  .2  per  cent.  The  result  is  then  set  down  and 
checked  by  addition  of  the  total  to  100  per  cent.  Arithmetic  or 
logarithmic  methods  can  be  applied  similarly.  The  schedule  given 
below  is  for  the  purpose  of  making  more  clear  the  methods  of  com- 
puting and  also  to  summarize  the  procedure  of  one  of  the  more 
complicated  multi-stage  analyses. 

Total  weight  of  sample  =  13.79  kg. 

Sieve  grades  Weight 

+64  mm.,  separate  washed        1.32  kg. 
+32    "  "  "  2.61    " 

+16    "  "  "  1.76    " 


Total  5.69  kg.        13.79  kg. 

5.69    " 


— 16  m.,  total  weight  (Too  sticky  for  sifting)        8.10  kg. 

Dried,  mixed,  quartered  down 

total  weight  used  4.17  kg. 

Small  quantity  shaken  over  1/16  mm.  sieve  to  secure  about 
10  grams  of  normal  — 1/16  grade.  Rest  returned  and 
total  of  close  to  4.17  grams  washed  in  jar  with  hose  to 


MECHANICAL  ANALYSIS  OF  SEDIMENTS  45 

1/32  grades.    Residue  then  dried  and 


take  out  bulk  of 
sifted. 
Sieve  grades 

-f-8  mm.  separate 

+4 
+2 


Weight 
.73  kg. 
.54  " 
.48    " 


Total 


1.75  kg. 

Weight 

4.16  total 

-16 

mm. 

1.75  total  16-2 

mm. 

Total  —2  grade  2.42  kg. 

This  residue  of  2.42  kg.  was  quartered  down  to  47.31  grams 
and  sifted. 


Sieve  grades 

Weight 

+1.      mm., 

separate 

10.31  gm. 

+1/2     » 

>> 

11.73    " 

+1/4     » 

97 

6.30    " 

+1/8     " 

yy 

4.29    " 

+1/16  " 

99 

3.89    " 

36.52  gm. 

47.31  gm.  total  -2        mm. 

36.52    "        "    2-1/16  mm. 


10.79  gm.  total  -1/16  mm. 
Then  -1/16  remaining  is  less  than  the  total  amount  by- 
amount  of  that  washed  out.     Some  of  the  material 
originally  saved  from  the  -16  grade  above  is  used  for 
the  elutriation. 
Settling  grades. 

4/3    mm.  per  sec.  separate  1.83  gm. 
4/9       "       "       "  "      1.64    " 

4/27     "       "       "  "        .89    " 

-4/27     "       ,?       "  "        .15    ,J 


Total  4.15  gm. 

Computation  usually  performed  by  slide  rule. 


46 


IOWA  STUDIES  IN  NATURAL  HISTORY 


Total    sample  of  13.79  kg. 


=  100% 


then  +64  " 

of 

1.32 

>? 

= 

9.6% 

+32  " 

of 

2.61 

y  y 

= 

18.9% 

+16  " 

of 

1.76 

j  y 

= 

12.8% 

-16  " 

of 

8.10 

y  y 

= 

58.7% 

Total  -16  " 

of 

4.17 

f> 

= 

58.7% 

then  +8     " 

of 

.73 

y  y 

= 

10.3% 

+4     " 

of 

.54 

y  y 

= 

7.6% 

+2     " 

of 

.48 

y  y 

= 

6.8% 

-2     " 

of 

2.42 

y  y 

= 

34.0% 

Total  -2     " 

of  47.31 

gm. 

= 

34.0% 

then  +1     " 

of 

10.31 

y  y 

= 

7.4% 

+1/2     " 

of 

11.73 

y  y 

= 

8.4% 

+1/4     " 

of 

6.30 

y  y 

= 

4.5% 

+1/8     " 

of 

4.29 

y  y 

= 

.13% 

+1/16  " 

of 

3.89 

?? 

= 

2.8% 

-1/16  " 

of  10.79 

y  y 

= 

7.8% 

Total  -1/16  s 

sample  of  4.51 

gm. 

= 

7.8% 

then  +4/3  mm.  i 

sec.  sa 

mple  of  1.83 

gm. 

= 

3.2% 

+4/9 

>  > 

>> 

y  y 

of  1.64 

y  y 

= 

2.8% 

+4/27 

?  ? 

>? 

y  y 

of 

.89 

y  y 

= 

1.5% 

-4/27 

>  ? 

>  ? 

y  y 

of 

.15 

y  y 

£= 

.3% 

Check 


100.0% 


Choice  of  Plotting  Scales 
When  the  grade  scale  has  been  decided  upon  and  the  analyses 
made  and  computed  there  still  remain  a  variety  of  forms  in  which 
the  results  may  be  presented.  If  a  graphic  form  is  chosen,  whether 
pyramidal  or  cumulative  as  described  below,  choice  must  be  made 
in  either  case  whether  the  coarse  grades  shall  be  at  the  left  or  at  the 
right  of  the  diagram  and  what  ratio  shall  obtain  between  the  vertical 
percentage  scale  and  the  horizontal  grade  scale.  A  large  number  of 
different  conventions  have  been  used  in  the  past  with  the  result  that 
direct  comparison  between  the  results  obtained  by  different  students 
has  been  impossible.38    The  great  diversity  which  can  be  developed 


38  Goldman,  M.  I.,  Petrography  and  Genesis  of  the  Sediments  of  the  Upper 
Cretaceous  of  Maryland,  pp.  169-170,  Baltimore,  1916. 

Woodford,  A.  O.,  The  San  Onofre  Breccia,  Univ.  of  Calif.,  Publications, 
Bull,  of  the  Dept.  of  Geol.  Sciences,  Vol.  15,  No.  7,  p.  175,  1925. 

Holmes,  A.,  Petrographic  Methods  and  Calculations,  pp.  217-225,  London, 

1921. 

(Footnote  continued  on  page  48) 


MECHANICAL  ANALYSIS  OP  SEDIMENTS 


47 


48 


IOWA  STUDIES  IN  NATURAL  HISTORY 


in  the  composition  diagram  of  a  given  sediment  by  the  use  of  differ- 
ent grade  scales  and  plotting  conventions  is  shown  in  Figure  3.  Plot- 
ting with  the  coarse  grades  at  the  left  has  seemed  to  be  most  con- 
venient and  the  card  shown  in  Figure  4  is  used  in  the  sedimentation 
laboratory  at  the  University  of  Iowa.  The  grade  scale  spaces  on  this 
card  are  made  to  conform  with  vertical  spacing  of  a  typewriter  so 


100 


80 


60 


40 


20 


N     H      N     *      *     «      N 


I  I  I  I  I  ITTTff 

Fig.  4.     Form  card    used  in    plotting  histograms    to  the 
1-2-4-8  mm.  scale  at  the  University  of  Iowa. 

that  the  percentages  may  be  filled  in  on  a  machine  if  desired.  The 
ratio  between  vertical  and  horizontal  scales  is  such  that  100  per  cent 
is  equal  to  20  grades  of  the  ratio  2.  By  the  use  of  such  a  card  for 
plotting  all  analyses  as  a  laboratory  record  the  diagrams  are  im- 
mediately available  in  any  combination  or  arrangement  without  re- 
drawing for  reproduction  by  zinc  etching  and  much  time  is  saved 
in  publication.  The  scale  of  reproduction  can  be  varied  somewhat 
without  interfering  greatly  with  comparison  provided  the  ratio  be- 
tween vertical  and  horizontal  scale  is  maintained  constant. 


Baker,  H.  A.,  Geol.  Magazine,  pp.  411-420,  463-467,  1920. 

Dake,  C.  L.,  The  Problem  of  the  St.  Peter  Sandstone,  Missouri  School  of 
Mines  Bulletin,  Vol.  VI,  No.  1,  Plates  V-XH,  incl.,  1921. 

Trowbridge,  A.  C,  and  Mortimore,  M.  E.,  Correlation  of  Oil  Sands  of  Sedi- 
mentary Analysis,  Economic  Geology,  Vol.  XX,  No.  5,  p.  417,  1925. 


MECHANICAL  ANALYSIS  OP  SEDIMENTS 


49 


Distribution  and  Cumulative  Diagrams 
Two  types  of  diagrams  are  in  current  use  and  both  have  good 
claims  for  recognition.  The  distribution  pyramid  shown  in  Figure  5 
has  the  advantage  that  it  is  a  strict  presentation  of  numerical  facts. 

700   i 1 1 1 1 1 »  700 


eo 


to 


40 


20 


80 


60 


40 


BO 


8   4    2     /    >/*  &  ?/8  8    4    2    7    %  ft  /a 

Fig.  5.     Histogram  and  cumulative  curve  for  the  same  composition. 

There  is  no  element  of  interpretation  in  it.  It  is  probably  more 
readily  visualized  by  persons  unaccustomed  to  either  than  is  the 
cumulative  diagram.  The  latter  diagram  is  partially  interpretative 
in  the  drawing  of  the  smoothed  curve  and  permits  the  presentation 
of  several  diagrams  in  one  plot.  It  also  permits  the  plotting  of 
analyses  made  to  different  grade  scales  on  the  same  diagram  more 


50 


IOWA  STUDIES  IN  NATURAL  HISTORY 


readily.  It  seems  that  each  type  of  scale  has  its  own  advantages 
and  that  both  may  sometimes  be  needed  to  convey  most  effectively 
this  type  of  data. 

Transformation  of  Grade  Scales 
Analyses  made  to  any  grade  scale  may  be  plotted  on  the  cards 
shown  in  Figure  4  directly  in  the  pyramidal  form  by  drawing  inter- 


% 
700 


/? 


SO 


oo 


in. 


Fig.  6A.    Histogram  of  original  analysis. 

mediate  vertical  lines  at  the  abscissae  points  of  the  new  grade  scale 
and  filling  in  the  new  columns  thus  made.  The  comparison  of  such 
diagrams  with  those  made  to  the  normal  grade  scale  is  difficult  un- 
less the  two  are  very  closely  juxtaposed  and  it  is  preferable  to  trans- 
form the  analysis  in  question  to  the  standard  grade  scale.  This  is 
done  by  plotting  the  analysis  in  the  cumulative  form  and  drawing  a 
smooth  curve  through  the  fixed  points.  Ordinates  may  now  be  read 
on  the  curve  for  the  abscissae  points  of  the  standard  grade  scale 
and  the  pyramid  plotted  for  these  values  as  read.  (Figure  6.) 
Similar  methods  may  be  used  for  constructing  a  pyramidal  diagram 
of  smaller  grade  ratios,  Figure  6-D.    No  more  information  is  added 


MECHANICAL  ANALYSIS  OF  SEDIMENTS 


51 


in  such  transformation  and  the  result  is  slightly  less  accurate  than 
the  fundamental  pyramid  of  the  grade  scale  of  analysis  but  the  form 
may  be  more  favorable  for  interpretation.39 


700 


<0 


e> 


*0 


<0 


<0 


SO 


00 


8 


* 


* 


CM 


* 


* 


«? 


o  in 


L^-jr" 

rr 

\ } 

t 

V 

1 

1  1 

1 

x\ 

* 


&  mm. 


$. 


Fig.  6B.    Cumulative  curve  used  in  reading  ordinates  at  absciss©  points 
of  desired  scales. 


39  This  paper  is  to  be  followed  by  another  consisting  of  a  graphic  compila- 
tion of  several  hundred  mechanical  compositions  of  modern  sediments  for  com- 
parison and  reference. 


V. 
TOO 


52  IOWA  STUDIES  IN  NATURAL  HISTORY 

C  *  D 


*?0 


oo 


$%$***+*  &&&&&mm 


Fig.  6C.     Histogram  of  same  data  trans- 
formed 1-2-4-8  mm.  scale. 


0O 


30 


SO 


§   S>  go  *  M  k  S 


***^«/l,/^ 


Fig.  6D.  The  same  plotted  to  twice  the 
number  of  grades,  i.e.,  ratio  of  the  square 
root  of  2. 


NEW  SEBIES  No.  120  DECEMBER  1,  1926 


UNIVERSITY  OF  IOWA 
STUDIES 


STUDIES  IN  NATURAL 
HISTORY 


VOLUME  XI  NUMBER  12 


AN  ECOLOGICAL  STUDY  OF  THE  FISHES  OF 
THE  LAKE  0K0B0JI  REGION 


by 

Austin  P.  Larrabee 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY,  IOWA 


Issued  semi-monthly  throughout  the  year.     Entered  at  the  post  office  at  Iowa  Cilv    Iowa 
as  second  class  matter  under  the  Act  of  October  3,  1917 


UNIVERSITY  OF  IOWA  STUDIES 
IN  NATURAL  HISTORY 


Henry  Frederick  Wickham,  Editor 


VOLUME  XI  NUMBER  12 


AN  ECOLOGICAL  STUDY  OF  THE  FISHES  OF 
THE  LAKE  0K0B0JI  REGION 

by 

Austin  P.  Larrabee 


PUBLISHED  BY  THE  UNIVERSITY,  IOWA  CITY,  IOWA 


Fig.  1.  Map  of  the  Lake  Okoboji  Region,  showing  collecting  stations 


1-8.       West  Okoboji  Lake 

1.  Miller's  Bay 

2.  Sand-bar 

3.  Gull  Point 

4.  Emerson's  Bay 

5.  Drainage  Canal 

6.  Deep  Hole,  Emerson  Bay 

7.  Smith's  Bay 

8.  North  End 
9-11.     Spirit  Lake 

9.  East  Bay 

10.  Crandall's  Lodge 

11.  Opposite  Hottes  Lake 
12.     Little  Spirit  Lake 

13-17.     East  Okoboji  Lake 

13.  Outlet  of  Spirit  Lake 

14.  Drawbridge 

15.  Kline's  Bay 

16.  Rocky  Point 

17.  Outlet 


18. 
19. 
20. 
21. 
22. 
23. 
24. 
25. 
26-30. 


31. 


Middle  Gar  Lake 
Lower  Gar  Lake 
Hottes  Lake 
Robinson  Lake 
Marble  Lake 
Sunken  Lake 
Reed  Creek 
Thomas  Creek 
Little  Sioux  River 

26.  West  Branch 

27.  East  Branch 

28.  Below  junction  of  26  and  27 

29.  Near  Hanging  Bog 

30.  Big  Bend 
Welch  Lake 


v  ct 


^       ^-^..  M-: 


AN  ECOLOGICAL  STUDY  OF  THE  FISHES 
OF  THE  LAKE  OKOBOJI  REGION 

INTRODUCTION 

This  paper  contains  the  results  of  studies  of  the  fishes  of  the  Lake 
Okoboji  region,  made  by  the  writer  during  the  summers  of  1921, 
1922,  1924,  and  1925.  The  writer  spent  in  all  thirty-five  weeks  at 
the  Lakeside  Laboratory  while  carrying  on  this  work.  At  first  the 
intention  was  to  investigate  the  distribution  of  certain  fishes  in  the 
lakes  with  the  factors  involved,  but  this  was  enlarged  later  to  in- 
clude the  listing  of  all  the  fishes  found  there  together  with  their 
ecological  habitats.  The  paper  includes  the  studies  not  only  of  lake 
fishes  but  also  of  certain  creek  fishes  and  those  of  the  Little  Sioux 
River. 

Through  the  courtesy  of  the  Iowa  State  Fish  and  Game  Depart- 
ment, the  writer  was  allowed  to  collect  the  fishes  necessary  for  this 
study.  For  this  purpose  seines  were  commonly  used,  and  at  times 
the  hook  and  line.  This  was  supplemented,  when  there  was  oppor- 
tunity, by  the  examination  of  fishes  in  live  bait  boxes  and  in  the 
catches  of  the  local  fishermen,  together  with  such  information  as 
could  be  obtained  regarding  fishes.  The  location  of  the  various 
collecting  stations  is  shown  in  Figure  1,  a  map  of  the  region.  At 
the  time  of  collecting,  notebook  records  were  made  of  the  time  of 
day,  temperature,  and  weather  conditions,  as  well  as  data,  regarding 
the  different  species  and  the  numbers  of  each  taken.  The  fish  for 
identification  were  kept  alive  if  possible.  Others  were  preserved  in 
10%  formalin.  In  case  the  food  of  the  fish  was  to  be  determined, 
the  body  cavity  was  opened  so  as  to  allow  the  preservative  free  ac- 
cess to  the  digestive  tract.  This  examination  was  made  at  the  labor- 
atory as  soon  as  possible  after  collecting.  The  fish  was  first  meas- 
ured and  the  length,  which  did  not  include  the  caudal  fin,  recorded. 
Then  the  stomach  and  intestines  were  removed,  slit  open,  and  the 
contents  carefully  scraped  out  on  a  glass  slide.  The  materials  were 
examined  mainly  under  a  dissecting  microscope,  using  the  com- 
pound microscope  when  necessary.  The  different  constituents  were 
then  teased  apart  and  segregated  with  needles  and  the  percentage 
of  the  volume  of  each  estimated. 


4  IOWA  STUDIES  IN  NATURAL  HISTORY 

But  little  work  has  been  done  with  the  fishes  of  this  region.  Meek 
collected  here  in  1890  and  records  eighteen  species  from  Spirit, 
East,  and  West  Okoboji  Lakes.1  Everman  also  visited  Spirit  Lake 
in  1892.  The  statements  made  in  his  itinerary  are  brief  and  con- 
cise. 

"Nov.  1.     Went  to  Spirit  Lake,  Iowa. 

"Nov.  2.  Cold  weather  having  set  in,  we  decided  to  close  the 
work  here  and  return  to  Washington. '  '2 

Although  his  stay  was  brief,  he  found  one  of  the  eighteen  species 
recorded  by  Meek.  More  recently,  in  October,  1920,  Mr.  Carfield, 
Superintendent  of  Fish  Culture  of  the  U.  S.  Biological  Station  at 
Fairport,  Iowa,  visited  the  lakes,  making  an  investigation  of  the 
conditions  affecting  the  supply  of  fishes,  especially  of  the  game  fishes. 

In  a  letter  to  Mr.  W.  A.  Albert,  State  Fish  and  Game  Warden,  he 
casually  mentions  fourteen  species  occurring  in  the  lakes.  These 
are  referred  to  by  their  common  names,  making  exact  identification 
often  difficult  or  impossible.  However,  three  new  species  are 
added  to  Meek's  list.  One  of  them,  the  common  carp,  Cyprinus 
cwrpio,  was  introduced  into  the  lakes  after  Meek  and  Evermann 
were  there.  The  other  two,  the  channel  cat,  Ictalurus  punctatus, 
and  the  white  bass,  Roccus  chrysops,  are  probably  native  but  have 
had  their  original  numbers  increased  through  stocking  by  the  State 
Department. 

The  writer  wishes  to  express  his  indebtedness  to  Dr.  F.  A.  Strom- 
sten  for  the  advice  given  and  suggestions  made  during  the  progress 
of  this  study  and  in  the  preparation  of  the  manuscript.  His  friend- 
ly interest  has  been  an  invaluable  aid  throughout.  The  writer  is 
indebted  also  to  Mr.  W.  A.  Albert,  State  Fish  and  Game  Warden, 
for  permission  to  collect  fishes  and  for  information  given,  and  to  the 
U.  S.  Fish  Commission  for  literature  supplied.  He  owes  much  to 
Mr.  Will  Shear,  Warden  in  charge  of  the  Fish  Hatchery  at  Orleans, 
and  to  Mr.  Frank  P.  Hopkins  of  Spirit  Lake  for  assistance  freely 
and  willingly  given.  Their  knowledge  of  the  fishes  and  of  their 
haunts  has  been  of  great  value  in  making  this  study.  He  is  indebt- 
ed, also,  to  Mr.  Harry  Tennant  for  his  courtesy  in  allowing  the 
writer  free  access  to  his  mounted  specimens  of  fishes  and  for  infor- 
mation given.     And  for  aid  in  collecting  and  in  other  ways,  the 


i  Meek,  S.  E.  Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska. 
Bull.  U.  S.  F.  C,  Vol.  14,  p.  133-138,  1894. 

2  Evermann,  B.  W.  and  Cox,  IT.  O.  Report  on  the  Fishes  of  the  Missouri 
River  Basin.    Rep.  U.  S.  Comm.  of  Fish  and  Fisheries,  p.  352-429,  1894. 


FISHES  OF  THE  OKOBOJI  REGION  5 

writer  expresses  his  appreciation  to  Professors  H.  M.  Kelly  and 
Albert  Kuntz,  and  to  Messrs.  E.  M.  Fitch,  J.  W.  Breukelman,  G.  E. 
Potter,  and  D.  T.  Jones.  To  all  these  as  well  as  to  others  unnamed, 
the  writer  wishes  to  record  his  thanks. 

LIST  AND  CLASSIFICATION  OF  THE  FISHES 
OF  THE  LAKE  OKOBOJI  REGION 

The  following  is  a  systematic  outline  of  the  fishes  recorded  from 
this  region.  But  one  sub-class,  the  Teleostomi,  of  the  class  Pisces, 
the  true  fishes,  is  concerned.  Seven  orders  of  this  sub-class  are 
represented  here.  The  classification  employed  is  based  on  that  of 
Jordan  and  Evermann  with  the  adoption  of  certain  changes  made 
by  Jordan  in  his  recent  work  on  fishes.3  The  species  recorded  by 
Meek  are  indicated  by  a  letter  M  after  them.  If  a  species  has  not 
been  observed  by  the  author,  it  is  bracketed. 
Series  Ganoidea. 

Order  Selachostomi.    The  Paddlefishes. 
Family  Polyodontidae.    The  Paddlefishes. 
Polyodon  spathula  (Walbaum).    Spoonbill. 
Order  Rhomboganoidea.    The  Garpikes. 
Family  Lepidosteidae.    The  Garpikes. 
Lepidosteus  osseins  (Linnaeus).    Long-nosed  Gar.  M. 
Lepidosteus  platystomus  (Rafinesque).    Short-nosed  Gar, 
Series  Teleostei. 
Order  Isospondyli. 

Family  Hiodontidae.    The  Mooneyes. 

Hiodon  alosoides  (Rafinesque).    Northern  Mooneye. 
Family  Salmonidae.    The  Salmon  Family. 

Cristivomer  namaycush  (Walbaum).     Great  Lake  Trout. 
Order  Eventognathi. 

Family  Catostomidae.    The  Suckers. 

Ictiobus  cyprinella   (Cuvier  &  Valenciennes).     Big-mouth 

Buffalo. 
Ictiobus  bubalus  (Rafinesque).     Small-mouth  Buffalo. 
Carpiodes  carpio  (Rafinesque).    Common  River  Carp. 
Catostomus  commersonii  (Lacepede).    Common  Sucker.4 
Moxostoma  aureolum  (Le  Sueur).    Common  Red-horse. 


3  Jordan,  D.  S.    Fishes.    D.  Appleton  &  Co.,  N.  Y.,  1925. 

4  Another  sucker,  C.  nigricans  probably,  has  been  reported  to  the  author  who 
has  not  been  able  to  verify  the  report. 


IOWA  STUDIES  IN  NATURAL  HISTORY 

Family  Cyprinidae.    The  Minnow  Family. 

Cyprinus  carpio  Linnaeus.    Common  Carp. 

Hybognathus  nuchalis  Agassiz.    Silvery  Minnow. 

Pimephales  notatus  (Rafinesque).    Blunt-nosed  Minnow. 

Semotilus  atromaculatus  (Mitchill).    Horned  Dace. 

Abr amis  cry soleucas.     (Mitchill).    Golden  Shiner.    M. 

Cliola  vigilax  (Baird  &  G-irard).    Bullhead  Minnow. 

Notropis  cayuga  Meek.    Cayuga  Minnow. 

Notropis  heterodon  (Cope).    Variable-toothed  Minnow. 

Notropis  blennius  (Girard).     Straw-colored  Minnow. 

Notropis  hudsonius  (De  Witt  Clinton).    Shiner.  M. 

Notropis  lutrensis  (Baird  &  Girard).    Red-finned  Minnow. 

Notropis  jejunus  (Forbes).    Shiner. 

Rhinichthys  atronasus  (Mitchill).    Black-nosed  Dace. 

Hybopsis  storerianus  (Kirtland).    Storer's  Chub. 
Order  Nematognathi.    The  Catfishes. 

Family  Siluridae.    The  Catfishes  and  Bullheads. 

Ictalurus  pimctatus  (Rafinesque).    Channel  Cat, 

Ameiurus  natalis  (Le  Sueur).    Yellow  Bullhead. 

Ameiurus  nebulosus  (Le  Sueur).    Speckled  or  Brown  Bull- 
head. 

Ameiurus  melas  (Rafinesque).    Black  Bullhead. 

(Leptops  olivaris  Rafinesque.    Flat-head  Cat.) 
Order  Haplomi. 

Family  Esocidae.    The  Pikes  and  Pickerels. 

Esox  lucius  Linnaeus.    Common  Pike.    M. 
Family  Poeciliidae.    The  Killifishes. 

Fundulus  diaphanus  menona  (Jordan  &  Copeland).  Menona 
Top-minnow. 

(Fundulus  zebrinus  Jordan  &  Gilbert.    M.)5 
Order  Acanthopteri.    The  Spiny-rayed  Fishes. 
Family  Gasterosteidae.    The  Sticklebacks. 

Eucalia  inconstans  (Kirkland).    Brook  Stickleback. 
Family  Percopsidae.    The  Trout-perches. 

Percopsis  guttatus  Agassiz.    Trout-perch.    M. 
Family  Centrarchidae.    The  Sunfishes. 

Pomoxis  annularis  Rafinesque.    White  Crappie. 

Pomoxis  sparoides  (Lacepede).    Black  Crappie.    M. 

Ambloplites  rupestris  (Rafinesque).    Rock  Bass. 


s  For  discussion  of  this  record,  see  page  15. 


FISHES  OP  THE  OKOBOJI  REGION  7 

Apomotis  cyanellus  (Rafinesque).     Green  Sunfish. 

Lepomis  megalotis  (Rafinesque).    Long-eared  Sunfish. 

Lepomis  humilis  (Girard).    Orange-spotted  Sunfish. 

Lepomis  potllidus  (Mitehill).    Bluegill.    M. 

Eupomotis  gibbosus  (Linnaeus).    Common  Sunfish.    M. 

(Micropterus    dolomieu    Lacepede.     Small-mouthed    Black 
Bass.    M.) 

Micropterus  salmoides   (Lacepede).     Large-mouthed  Black 
Bass.    Mi. 
Family  Percidse.    The  Perch  Family. 

Stizostedion  vitreum  (Mitehill).    Wall-eyed  Pike.    M. 

Stizostedion  canadense  griseum  (De  Kay).    Sauger.    M. 

Perca  flavescens  (Mitehill).    Perch.    M. 

Percina  oaprodes  (Rafinesque).    Log-perch. 

Boleosoma  nigrum  (Rafinesque).    Johnny  Darter.    M. 

Etheostoma  iowce  Jordan  &  Meek.    Iowa  Darter.    M. 
Family  Serranidse.    The  Sea  Bass. 

Roccus  clvrysops  (Rafinesque).    White  Bass. 
Family  Sciaenidse.    The  Drums  or  Croakers. 

Aplodinotus  grunniens  Rafinesque.    Sheepshead. 

HABITAT  AND  DISTRIBUTION 

Polyodon  spathula  (Walbaum).    Spoonbill;  Paddlefish 

No  specimens  of  the  spoonbill  have  been  taken  by  the  writer. 
Several  large-sized  ones,  however,  have  been  taken  during  the  past 
twelve  or  fifteen  years  in  East  and  West  Okoboji  Lakes.  These 
have  been  taken  mainly  during  the  fall  and  winter  months.  An 
extremely  large  one,  and  the  largest  one  yet  recorded,  as  given  in 
the  Okoboji  Protective  Association  Bulletin,  No.  12,  1916,  measured 
six  feet  and  nine  inches  in  length,6  and  weighed  185  pounds.  This 
individual,  a  male,  was  speared  by  a  fisherman,  R.  Vandergeek, 
through  the  ice  near  the  north  end  of  West  Okoboji  Lake  in  the 
winter  of  1915-1916.  The  same  article  relates  the  capture  of  an- 
other one,  also  speared  through  the  ice,  off  Pillsbury's  Point  in  the 
same  lake.  This  one,  which  was  a  female,  is  reported  to  have  weighed 
210  pounds  and  to  have  measured  six  feet  and  seven  inches  from  tip 
to  tip.  The  author  has  found  on  investigation  that  the  weight  of 
the  latter  paddlefish  was  exaggerated.    Mr.  Hopkins,  in  a  letter  to 

«  Measurements  are  from  tip  to  tip. 


8  IOWA  STUDIES  IN  NATURAL  HISTORY 

the  author  writes,  " it  weighed,  when  Mr.  Tennant  received  it, 

168  pounds  and  had  been  out  of  the  water  a  week.  Mr.  Tennant 
estimated  its  weight  not  over  175  pounds  when  speared."  This 
specimen  and  a  third  one  were  mounted  by,  and  are  in  the  possession 
of  Mr.  Tennant  who  has  given  the  writer  the  opportunity  of  exam- 
ining them.  The  third  paddlefish,  which  was  caught  in  a  gill  net  in 
Miller's  Bay  in  January,  1918,  measured  six  feet  and  four  inches 
over  all  and  weighed  146  pounds.  At  least  five  other  large-sized 
ones,  although  considerably  smaller  than  those  discussed,  have  been 
taken  in  East  or  West  Okoboji  Lakes.  But  none  have  been  taken 
since  1918  although  certain  fishermen  have  reported  that  they  have 
seen  others. 

It  seems  probable  that  very  few  if  any  spoonbills  still  exist  in  the 
lakes,  and  that  the  number  has  been  limited  in  the  past.  The  species 
is  one  of  rivers  and  larger  streams  rather  than  of  lakes,  occurring 
in  waters  with  muddy  bottoms.  Yet  it  is  in  the  lakes  that  the  larg- 
est individuals  have  been  found.  Evermann  and  Clark  record  two 
from  Lake  Manitou,  Indiana,  weighing  173  and  163  pounds  re- 
spectively.7 Forbes  and  Eichardson  mention  another  large  speci- 
men from  Lake  Tippecanoe,  Indiana,  which  weighed  150  pounds.8 
Similar  examples  from  other  lakes  are  on  record.  The  large  size 
attained  in  the  lakes  may  be  due  in  large  measure  to  the  favorable 
food  conditions  found  there.  For  the  lakes  furnish  for  this  species 
an  especially  abundant  supply  of  food  which  consists  largely  of 
entomostraca  and  insect  larvae. 

Lepidostens  osseus  (Linnaeus).  Long-nosed  Gar 
This  species  is  reported  by  Messrs.  Hopkins  and  Shear  to  be  com- 
monly distributed  in  the  three  major  lakes  of  this  region.  But  few 
have  been  taken  with  seine  during  the  summer.  These  were  seined 
over  both  muddy  and  sandy  bottoms.  Apparently  this  species  pre- 
fers deeper  water  in  the  summer  than  the  Short-nosed  Oar.  Other- 
wise the  two  resemble  each  other  closely  in  their  habits  and  distribu- 
tion. 

Lepidosteus  platystomus  (Rafinesque).    Short-nosed  Gar 
This  fish  occurs  commonly  in  waters  of  shallow  to  moderate  depths, 
mainly  among  aquatic  vegetation  and  over  both  muddy  and  sandy 
bottom.     Both  this  and  the  preceding  species  have  the  habit  of 


7  Evermann  and  Clark,  Lake  Maxinkuckee,  p.  310. 
s  Forbes  and  Eichardson,  Fishes  of  Illinois,  p.  17. 


FISHES  OF  THE  OKOBOJI  REGION  9 

floating  on  the  surface  for  some  time,  resembling  a  stick  in  the 
water.  This  may  be  of  some  value  in  catching  their  prey,  although 
none  have  been  observed  to  feed  at  such  times.  The  jaws  armed 
with  sharp  teeth  are  well  fitted  for  seizing  and  holding  their  prey. 
Mr.  6.  E.  Potter  found  the  food  of  the  adults  here  to  consist  of 
about  60%  fish  and  40%  crayfish.9 

Hiodon  alosoides  (Rafinesque).  Northern  Mooneye 
This  species  is  of  rare  occurrence  in  the  lakes.  The  writer  has 
taken  none  and  has  learned  of  but  two  specimens  being  taken.  One 
of  these  was  caught  in  East  Okoboji  Lake  in  August,  1922.  This 
specimen  was  not  seen  by  the  writer  but  a  plaster  mold  of  it  made 
by  a  storekeeper  in  Orleans  was  examined.  The  diagnostic  char- 
acter of  the  species,  the  dorsal  fin  with  nine  rays  and  placed  slight- 
ly posterior  to  the  ventral  one,  was  clearly  evident  in  the  imprint. 
The  other  specimen  was  caught  several  years  ago  in  Minnewashta 
Lake,  the  Middle  Gar  Lake.  It  was  mounted  and  kept  as  a  curiosity 
by  a  storekeeper  in  Arnold's  Park.  Here,  in  the  summer  of  1925, 
the  writer  had  the  opportunity  of  examining  and  identifying  it. 

Crist ivomer  namaycush  (Walbaum).  Great  Lake  Trout 
This  trout  is  not  a  native  here,  and  although  several  attempts  to 
introduce  it  have  been  made  during  the  past  twenty-five  years,  it 
probably  exists  now  in  limited  numbers  if  at  all.  It  has  been  intro- 
duced into  both  Spirit  and  West  Okoboji  Lakes,  mainly  in  the  latter. 
In  1922,  the  latest  attempt,  40,000  adult  trout  were  planted  in  West 
Okoboji  Lake.  On  the  whole,  these  different  attempts  have  not  been 
successful.  About  fifteen  years  ago  four  or  five  trout  were  caught. 
One  of  these  taken  in  Spirit  Lake  was  mounted  and  in  the  summer 
of  1925,  still  hung  on  the  wall  of  a  pool  room  in  the  town  of  Spirit 
Lake.  No  others  have  been  taken  so  far  as  the  writer  could  learn. 
The  Great  Lake  trout  in  general  requires  deep  cold  water,  appar- 
ently able  to  exist  under  such  conditions  with  a  relatively  small 
amount  of  oxygen.10  Spirit  Lake,  which  has  a  maximum  depth  of 
7.6  m.  and  only  a  slight  change  in  temperature  from  the  surface  to 
the  bottom,  evidently  furnished  unfavorable  conditions  for  this  fish. 
Successful  planting  could  not  be  expected  here.    West  Okoboji  Lake 

9  Potter,  G.  E.,  The  Food  of  the  Short-nosed  Garpike  (Lepidosteus  platy- 
stomus).    la.  Acad.  Sci.,  Vol.  XXX,  p.  167-170,  1923. 

io  Kemmerer,  George,  Bouvard,  J.  P.,  and  Boorman,  W.  R.  Northwestern 
Lakes  of  the  U.  S.  Biological  and  chemical  studies  with  reference  to  the  possi- 
bilities in  production  of  fish.    Bull.  Bur.  of  Fisheries,  Vol.  39,  p.  51-140,  1923-24. 


10  IOWA  STUDIES  IN  NATURAL  HISTORY 

with  a  maximum  dept  of  40.2  m.  has  both  the  depth  and  the  low 
temperature  required.  After  the  summer  stratification  has  taken 
place,  the  lowest  stratum,  the  hypolimnion,  remains  practically  uni- 
form in  temperature,  but  not  so  in  its  oxygen  content.  The  sources 
of  oxygen  are  cut  off,  for  the  hypolimnion  is  cut  off  from  the  air  by 
the  upper  two  layers  and  there  is  little  or  no  photosynthesis.  On  the 
other  hand,  through  decomposition  and  respiration  the  amount  of 
oxygen  is  decreased.  Birge  and  Juday,  on  July  31, 1919,  found  a  de- 
crease from  2.23  ce.  per  liter  at  15  m.,  with  a  slight  increase  at  18  m., 

to  0.86  cc.  at  33  m.  From  their  results,  they  state,  " it  is  safe  to 

predict  that  this  gas  all  disappeared,  from  the  lower  portions  of  the 
hypolimnion  at  least,  before  the  time  of  the  autumnal  overturn/711 
Students  of  Stromsten  have  found  such  to  be  the  case,  and  the 
amount  of  oxygen  decreased  in  the  upper  hypolimnion  so  as  to  make 
conditions  unfavorable  for  the  trout.  Again  the  food  supply,  large- 
ly of  fish,  may  be  limited  in  the  depths  which  the  trout  would  occupy 
in  summer.    The  author  has  no  evidence,  however,  to  support  this. 

Ictiobus  cyprimlla  (Cuvier  &  Valenciennes).  Big-mouth  Buffalo 
This  is  the  common  buffalo  fish  of  the  lakes,  occurring  in  the  three 
major  lakes  and  in  the  smaller  ones  adjoining  Spirit.  During  the 
summer  it  prefers  weedy  waters  six  to  eight  meters  deep  over  a  mud 
bottom,  although  the  writer  has  taken  three  specimens  in  East  Oko- 
boji  at  the  depth  of  two  to  three  meters.  During  the  spawning  sea- 
son in  the  spring,  buffalos  are  said  to  be  tolerably  common  in  the 
shallow  water  along  the  shores  where  the  eggs  are  deposited. 

Ictiobus  bubalus  (Rafinesque).     Small-mouth  Buffalo 
Meek  records  this  species,  reporting  two  or  three  specimens  taken 
in  East  Okoboji.    The  author  has  taken  none.    It  is  reported  from 
all  three  major  lakes,  occurring  in  much  less  numbers  than  the  pre- 
ceding species. 

Carpiodes  carpio  (Rafinesque).  Common  River  Carp 
This  species  has  not  been  taken  in  any  of  the  lakes,  but  occurs 
tolerably  commonly  in  the  Little  Sioux  River  where  it  was  seined 
by  the  author.  It  was  taken  most  commonly  in  the  swifter  waters 
of  the  West  Branch,  and  in  limited  numbers  only  below  the  junction 
of  the  two  branches  where  the  flow  was  less  rapid. 


ii  Birge,  E.  A.  and  Juday,  C.    A  Limnological  Reconnaissance  of  West  Oko- 
boji.    Stud,  in  Nat.  Hist.,  Univ.  of  la.,  IX,  No.  1,  p.  42,  1920. 


FISHES  OF  THE  OKOBOJI  REGION  ir 

Catostomus  commersonii  (Lacepede).  Common  Sucker 
The  common  sucker  occurs  commonly  in  the  major  lakes  and  in 
the  Gar  Lakes.  In  the  summertime,  it  is  found  in  the  deeper  waters 
mainly  on  a  rocky  bottom,  and  has  not  been  taken  with  the  seine 
along  shore.  It  is  also  tolerably  common  in  the  Little  Sioux  River, 
showing  a  preference  for  the  swifter  flowing  portions. 

Moxostoma  aureolum  (Le  Sueur).  Red-horse 
The  writer  has  not  taken  any  of  this  species  in  the  lakes.  Two 
specimens,  one  a  mounted  specimen  taken  by  Mr.  Tennant  in  East 
Okoboji  and  the  other  taken  in  West  Okoboji  by  Mr.  Hopkins,  have 
been  examined.  It  is  said  by  Mr.  Tennant  to  occur  in  the  Gar  Lakes 
also.  One  was  seined  by  the  writer  in  the  West  branch  of  the  Little 
Sioux  River.  Judging  from  the  statement  made  to  the  writer,  it  is 
evidently  an  uncommon  fish  in  this  region. 

Cyprinus  mrpio  Linnaeus.    Carp 

The  carp  first  appeared  in  the  lakes  fifteen  or  sixteen  years  ago, 
and  in  a  few  years  it  was  common  in  East  and  West  Okoboji  and 
in  the  Gar  Lakes.  High  water,  five  or  six  years  later,  enabled  it  to 
extend  its  range  into  Spirit  Lake  where  it  occurs  in  lesser  numbers 
than  in  the  other  lakes  mentioned.  It  prefers  weedy  muddy  bot- 
tomed portions  of  the  lakes  in  shallow  to  moderate  depths. 

In  the  Little  Sioux  River  two  specimens  of  the  variety  known  as 
the  mirror  carp  were  taken  in  July,  1922.  In  this  variety  the  scales 
are  few  and  much  enlarged  occurring  in  two  or  three  irregular  rows 
of  scales,  with  the  rest  of  the  body  naked.  None  of  these  have  been 
taken  in  the  lakes. 

Hybognathus  nuchalis  Agassiz.  Silvery  Minnow ;  River  Shiner 
This  minnow,  as  the  second  name  infers,  is  a  river  form,  occurring 
abundantly  in  the  Little  Sioux  mainly  over  a  muddy  bottom.  None 
have  been  recorded  from  any  of  the  lakes.  It  is  used  to  some  extent 
for  commercial  bait,  but  the  distance  to  the  river  makes  it  too  incon- 
venient to  be  commonly  used. 

Pimephales  notatus  (Rafinesque).  Blunt-nosed  Minnow;  Chub 
The  blunt-nosed  minnow  prefers  weedy  shallow  waters  with  mud- 
dy bottom.  The  writer  found  it  common  in  North  Hottes  Lake  but 
did  not  take  any  elsewhere  except  in  the  Little  Sioux  River,  al- 
though it  was  reported  by  Mr.  Shear  to  be  common  in  both  Spirit 
and  East  Okoboji  Lakes. 


12  IOWA  STUDIES  IN  NATURAL  HISTORY 

This  and  the  bullhead  minnow,  Cliola  vigilax,  are  the  ones  most 
commonly  used  for  bait  by  the  fishermen  at  the  lakes.  These  two 
resemble  each  other  so  closely  that  they  are  not  commonly  distin- 
guished as  separate  species.  Besides  the  generic  differences  of  the 
two,  notatus  has  a  blunter  nose  and  the  scales  on  the  upper  half 
of  the  body  are  dark-edged  due  to  the  concentration  of  the  minute 
dots  there.  Vigilax,  on  the  other  hand,  has  a  more  rounded  nose, 
and  the  specks  are  scattered  over  the  scales  rather  than  restricted 
to  the  edges. 

Semotilus  atromaculatus  (Mitchill).  Horned  Dace;  Creek  Chub 
This  is  a  typical  creek  fish,  occurring  commonly  in  both  Reed  and 
Thomas  Creeks.  This  is  one  of  the  pioneer  fishes  to  take  possession 
of  young  brooks  or  creeks.  It  is  found  especially  in  the  deeper 
pools  under  shelving  banks  or  tree  roots  where  the  current  is  strong 
enough  to  keep  the  water  clean  and  well  oxygenated. 

Abramis  crysoleucas  (Mitchill).  Golden  Shiner 
The  golden  shiner  was  taken  from  the  three  major  lakes  and  from 
Marble,  Hottes,  and  Robinson  Lakes.  It  was  found  most  common 
in  the  three  last  lakes,  showing  a  preference  for  weedy  and  compar- 
atively shallow  water  with  muddy  bottom.  In  East  Okoboji  and 
Spirit  Lakes,  a  limited  number  was  taken  over  a  sandy  bottom. 

Cliola  vigilax  (Baird  &  Oirard).  Bullhead  Minnow 
But  two  specimens  of  this  minnow  were  taken  by  the  writer  in 
the  major  lakes.  One  of  these  was  seined  in  Miller's  Bay,  West 
Okoboji  Lake,  the  other  near  CrandaH's  Lodge  at  the  north  end  of 
Spirit  Lake.  Both  were  taken  near  patches  of  weeds,  over  a  sandy 
or  gravelly  bottom.  Such  isolated  occurrences  suggest  the  possibil- 
ity that  these  had  escaped  from  the  bait  boxes  of  local  fishermen. 
The  writer  has  seined  it  in  large  numbers  in  Welch  Lake,  and  it  is 
reported  by  Mr.  Hopkins  to  be  as  common  in  Center  Lake.  In  Welch 
Lake  it  was  taken  in  shallow  water  over  a  muddy  bottom  compara- 
tively free  of  water  plants. 

Notropis  cayuga  Meek.  Cayuga  Minnow 
This  is  an  uncommon  minnow  in  this  region,  and  was  taken  m 
three  localities  only,  Miller's  Bay,  (West  Okoboji  Lake),  Hottes 
Lake,  and  Sunken  Lake.  In  the  first  two  it  was  taken  in  shallow 
water  between  the  water  weeds  and  the  shore  and  over  sandy  bot- 
tom.    But  in  Sunken  Lake  where  it  occurred  rather  commonly,  it 


FISHES  OF  THE  OKOBOJI  EEGION  13 

was  found  among  a  dense  growth  of  aquatic  vegetation,  mainly 
Elodea,  and  over  a  muddy  bottom. 

Notropis  heterodon  (Cope).  Variable-tooth  Minnow 
This  minnow  is,  in  general,  rare  in  the  lakes.  In  a  kettle  hole 
near  Stony  Point,  East  Okoboji,  it  was  found  tolerably  common. 
Here  it  was  taken  among  weeds  over  a  bottom  of  sandy  silt.  Other- 
wise it  was  not  taken  except  in  Miller's  Bay  where  a  half  dozen  in 
all  were  seined.  The  conditions  were  the  same  as  those  given  for 
cayuga. 

These  two  minnows,  heterodon  and  cayuga,  resemble  each  other 
closely.  The  latter  has  a  very  small  mouth  and  a  pale  chin,  while 
the  former  has  a  moderate  sized  mouth  and  a  black  chin. 

Notropis  blennhis  (Girard).  Straw-colored  Minnow 
This  species  is  common  in  the  Little  Sioux  River,  and  occurs  in 
limited  numbers  in  West  Okoboji  Lake  and  in  Reed  and  Thomas 
Creeks.  It  has  not  been  seined  in  any  other  of  the  lakes,  but  prob- 
ably occurs  in  East  Okoboji  at  least.  Apparently  it  prefers  the 
cool  running  waters  of  streams.  In  West  Okoboji  it  was  taken  in 
shallow  water  along  shore  over  a  sandy  bottom. 

Notropis  Kudsonius  (De  Witt  Clinton).  Shiner;  Spot-tailed  Min- 
now 
This  is  the  most  common  minnow  of  the  major  lakes.  None  were 
taken  in  any  of  the  minor  ones.  It  frequents  shallow  water  along 
shore  generally  over  a  sandy  or  gravelly  bottom.  Although  still 
common,  the  numbers  have  been  reduced  by  its  use  for  live  bait. 
Meek,  in  1892,  found  it  the  principal  minnow  used  for  this  purpose 
by  the  local  fishermen.12  That  it  is  not  the  principal  one  now  is  due 
to  its  lessened  numbers,  and  because  other  species  of  minnows  can 
be  more  easily  obtained  in  some  of  the  nearby  smaller  lakes. 

Notropis  lutrensis  (Baird  &  Girard).  Red-finned  Minnow 
This  minnow  is  a  river  dweller  occurring  rather  commonly  in  the 
Little  Sioux  River.  It  shows  a  preference  for  the  swift  water  of  the 
riffles  of  the  river.  Two  specimens  only  have  been  taken  in  the 
lakes.  One  of  these  was  taken  by  Mr.  Hopkins  from  the  East  Lake 
in  July,  1922.  The  second  one  was  seined  by  Messrs.  Jones  and 
Breukelman  in  Miller's  Bay  in  July,  1924.    It  seems  probable  that 


12  Meek,  Seth  E.    Fishes  of  Western  Iowa  and  Eastern  Nebraska,  p.  136. 


14  IOWA  STUDIES  IN  NATURAL  HISTORY 

these  two  had  escaped  from  minnow  boxes,  rather  than  occurring 
naturally  in  the  lakes. 

Notropis  jejunus  (Forbes).  Shiner;  Gull  Point  Chub 
This  shiner  is  apparently  a  localized  form  occurring  mainly 
around  Gull  Point,  West  Okoboji  Lake,  thereby  giving  it  the  name 
of  Gull  Point  Chub.  But  one  specimen  was  taken  by  the  writer. 
This  was  seined  August  4,  1922,  in  clear  shallow  water  over  a  sandy 
bottom. 

Rhimchthys  atronasus   (Mit chill).     Black-nosed  Dace 
The  black-nosed  dace,  like  the  horned  dace,  is  a  typical  creek  fish 
and  is  found  tolerably  common  under  similar  conditions  in  Reed 
and  Thomas  Creeks.    It  has  not  been  found  elsewhere  in  this  region. 

Hybopsis  storerianiis  (Kirtland).     Storer's  Chub;  River  Chub 
The  writer  has  seen  but  one  specimen  of  this  species,  this  one 
caught  by  Mr.  Hopkins  in  East  Okoboji  Lake.     Mr.  Shear  states 
that  it  is  common  in  the  Little  Sioux  River  and  is  taken  occasionally 
in  the  lakes  during  the  spring  seining. 

Ictalurus  punctatus  (Rafmesque).  Channel  Cat 
The  channel  cat  is  undoubtedly  a  native  of  this  region  as  speci- 
mens have  been  taken  in  the  Little  Sioux  River.  Mr.  Shear  informed 
the  writer  that  this  species  was  introduced  into  the  lakes  about  1913 
or  1914.  In  the  winter  of  1917-18,  eighteen  of  these  and  the  flat  head 
cats,  averaging  sixteen  pounds  in  weight,  were  taken  in  gill  nets. 
Small  fry  of  this  and  the  other  large  cat-fish  were  first  seen  in  the 
summer  of  1921.  In  1922,  the  State  Fish  and  Game  Department  in- 
troduced 30,000  adults  into  West  Okoboji  and  18,000  in  Spirit  Lake. 
A  few  are  caught  each  season.  The  writer  had  the  opportunity  to 
examine  one  caught  in  East  Okoboji  Lake  in  August,  1925. 

Amehiriis  natalis  (Le  Sueur).  Yellow  Bullhead;  Yellow  Cat 
This  bullhead  prefers  water  of  moderate  depth  with  muddy  bot- 
tom in  or  near  the  water  plants.  Its  range  extends  into  deeper 
waters  than  that  of  the  other  bullheads.  It  is  common  in  both  East 
and  West  Okoboji  Lakes,  and  occurs  in  lesser  numbers  in  Spirit 
Lake. 

Ameiurus  nebulosus  (Le  Sueur).    Common  Bullhead 
The  common  bullhead  shows  a  preference  for  the  same  conditions 
as  natalis  but  is  found  more  commonly  in  shallow  water.    It  is  toler- 


FISHES  OP  THE  OKOBOJI  REGION  15 

ably  common  in,  all  the  major  lakes,  but  was  found  especially  com- 
mon in  the  shallow  weedy  Robinson  and  Hottes  Lakes.  Here,  in 
1922,  the  local  fishermen  came  for  their  market  supply  of  bullheads. 

Ameiurus  melas  (Rafinesque).  Black  Bullhead 
Like  the  other  bullheads,  this  one  prefers  muddy  bottom  ranging 
in  depth  somewhat  between  the  other  two,  although  seined  from  as 
shallow  water  as  the  common  bullhead.  It  is  the  commonest  of  the 
bullheads  in  Spirit  Lake  and  occurs  rather  commonly  in  the  other 
major  lakes. 

Leptops  olivaris  (Rafinesque).  Flathead  Cat 
The  writer  has  not  collected  any  of  this  species.  Apparently  it 
wTas  introduced  accidentally  with  shipments  of  the  channel  cat,  7. 
punctatus.  As  noted  in  the  discussion  of  the  latter,  individuals  of 
the  flatheads  were  also  taken  in  the  gill  nets  in  the  winter  of  1917-18. 
Mr.  Hopkins  reported  one  caught  in  East  Okoboji  Lake  in  the  win- 
ter of  1925-26. 

Esox  lucius  Linnaeus.  Common  Pike;  Northern  Pickerel 
This  fish  occurs  commonly  in  the  lakes,  preferring  the  weedy  por- 
tions which  constitute  its  typical  habitat.  It  is  a  swift  predaceous 
fish  which  lies  in  wait  for  its  prey,  mainly  fish,  capturing  it  with  a 
quick  dash.  The  subcylindrical  shape  of  the  body  fits  it  for  moving 
in  between  the  stems  of  the  water  plants  without  hindrance.  This 
shape  may  be  of  further  aid  to  the  fish  because  of  its  resemblance 
to  a  submerged  stick,  which  would  be  increased  by  its  habit  of  re- 
maining nearly  motionless  in  the  water.  Thus  its  unsuspecting  vic- 
tim might  approach  within  capturing  distance. 

Fundulus  diaphanus  menona  (Jordan  &  Copeland).  Menona  Top- 
minnow 

The  top-minnow  is  found  most  commonly  in  the  shallow  water 
with  a  sandy  bottom,  either  in  the  weeds  or  between  them  and  the 
shore.  It  occurs  commonly  along  the  sand-bar  in  Miller's  Bay,  West 
Okoboji  Lake  during  August,  and  less  commonly  earlier  in  the  sea- 
son. It  was  seined  also  in  East  Bay,  Spirit  Lake,  and  in  Hottes 
Lake. 

Meek  recorded  F.  zebrinus  from  East  Okoboji  Lake.13  None  of 
the  specimens  taken  by  the  writer  could  be  referred  to  that  species. 


is  Meek,  S.  E.    Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska, 
p.  137. 


16  IOWA  STUDIES  IN  NATURAL  HISTORY 

Zebrinus  has  sixty  scales  in  the  lateral  series  and  twenty-one  trans- 
versely. There  are  fourteen  or  fifteen  rays  in  the  dorsal  fin,  and 
thirteen  or  fourteen  in  the  anal.14  The  specimens  collected  by  the 
writer  had  from  forty-two  to  fifty  scales  in  the  lateral  and  twelve  to 
fourteen  in  the  transverse  series  The  dorsal  had  twelve  to  thirteen 
rays  and  the  anal  ten  to  eleven.  If  Meek  was  correct  in  his  identifi- 
cation, apparently  menonti  has  supplanted  zebrinus  completely  or 
nearly  so.  The  occurrence  of  the  latter  seems  doubtful  enough  to 
warrant  its  omission. 

Euoalia  inconstans  (Kirtland).  Brook  Stickleback 
This  stickleback  was  seined  commonly  in  shallow  water  over  a 
mud  bottom  in  Swan  Lake,  Dickinson  County,  in  August,  1924. 
This  lake  is  in  the  drainage  system  of  the  Des  Moines  River.  How- 
ever, the  species  is  included  here  because  Mr.  Hopkins  had  taken  it 
in  Reed  Creek  before  the  sloughs,  once  characteristic  of  it,  were 
drained. 

Percopsis  givttatus  Agassiz.  Trout  Perch 
One  specimen  of  this  species  has  been  taken  in  the  lakes  by  the 
writer.  This  was  seined  in  East  Bay,  Spirit  Lake,  July  21,  1921,  in 
water  between  one  and  two  meters  deep,  over  a  sandy  bottom  and 
near  water  weeds.  Twelve  other  individuals  were  taken  in  the  Lit- 
tle Sioux  River,  July  28,  1922.  Meek  in  his  list  includes  the  state- 
ment of  Evermann  regarding  this  fish.  On  November  2,  1892,  the 
latter  found  four  specimens  in  the  minnow  box  of  a  hotel.  He 
states  further  that  Mr.  H.  E.  Owen,  then  proprietor  of  the  Lake  Park 
House  of  Spirit  Lake,  reported  the  species  as  "abundant  in  the 
lakes."15  While  this  statement  may  have  applied  at  that  time,  it 
certainly  does  not  now  for  the  trout  perch  is  evidently  uncommon  at 
present. 

Pomoxis  annadaris  Rafinesque.    White  Crappie ;  Crappie 
The  crappie  is  common  in  all  the  major  lakes.    It  shows  a  prefer- 
ence for  water  four  to  six  meters  deep  with  a  muddy  bottom,  in  or 
near  water  weeds.    It  comes  into  shallower  water  for  feeding  in  the 
evening. 


14  Jordan,  D.  S.  and  Everman,  B.  W.  Fishes  of  North-Middle  America,  Vol. 
I,  p.  646. 

is  Meek,  S.  E.  Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska, 
p.  137. 


PISHES  OF  THE  OKOBOJI  REGION  17 

Porno xis  sparoides  (Lacepede).  Black  Crappie;  Calico  Bass 
This  species  has  not  appeared  as  frequently  as  the  preceding  one 
in  seining.  Its  habitat  is  similar  to  that  of  the  white  crappie  with 
which  it  is  frequently  confused.  Besides  its  darker  markings,  this 
species  has  the  anal  fin  reticulated  with  dark  greenish  markings, 
while  the  anal  fin  of  annularis  is  nearly  plain.  Sparoides  has  seven 
or  eight  spines  in  the  dorsal  fin,  annularis  six. 

Ambloplites  rupestris  (Rafinesque).    Rock  Bass 
Only  three  individuals  of  this  species  have  been  taken,  all  from 
Miller's  Bay,  West  Okoboji  Lake.    It  is  said  by  Mr.  Shear,  to  occur 
in  limited  numbers  in  all  the  major  lakes.     It  prefers  moderate 
depths  with  rocky  bottom. 

Apomotis  cy melius  (Rafinesque).  Green  Sunfish 
This  sunfish  is  generally  found  in  or  near  water  weeds,  ranging 
from  near  the  shore  line  to  a  depth  of  three  to  four  meters.  It 
shows  a  preference  for  a  sandy  silt  bottom.  It  is  a  common  fish  in 
the  weedy  bays  of  West  Okoboji  and  occurs  less  commonly  in  East 
Okoboji  and  Spirit  Lakes. 

Lepomis  megalotis  (Rafinesque).  Long-eared  Sunfish 
This  fish  shows  a  preference  for  shallow  weedy  waters,  with  a 
bottom  of  mud  or  sandy  silt.  In  1922,  it  was  taken  in  considerable 
numbers  in  Robinson  Lake,  fifty-five  at  one  drag  of  the  seine.  Sev- 
eral were  also  seined  in  North  Hottes  and  two  in  East  Okoboji.  It 
was  not  recorded  elsewhere. 

Lepomis  humilis  (Girard).  Red-spotted  Sunfish 
The  red-spotted  sunfish  has  been  recorded  only  from  the  Little 
Sioux  River.  In  1924,  seven  adults  were  seined  in  the-west  branch 
of  the  river,  in  water  from  one  to  one  half  meters  deep.  In  August 
of  the  next  year,  six  young  of  that  season  were  taken  from  a  pool  in 
the  otherwise  dry  bed  of  the  river. 

Lepomis  pallidus  (Mitchill).  Bluegill 
With  the  exception  of  the  perch,  the  bluegill  is  the  most  abundant 
fish  in  the  three  major  lakes.  It  has  not  been  recorded  from  any  of 
the  smaller  ones.  It  is  found  under  a  variety  of  conditions  of  depth 
and  bottom.  It  is  frequently  taken  in  the  shallow  water  around 
docks,  but  its  more  characteristic  habitat  is  in  or  near  the  growths 
of  water  weeds. 


18  IOWA  STUDIES  IN  NATURAL  HISTORY 

Eupomotis  gibbosus  (Linnaeus).  Common  Sunfish;  Pumpkin-seed 
This  is  a  characteristic  fish  of  the  weedy  portions  of  the  major 
lakes,  in  water  of  shallow  to  moderate  depth,  and  in  the  shallow 
weedy  lakes,  Robinson  and  Hottes.  Like  the  bluegill,  it  is  found 
over  different  types  of  bottom  ranging  from  mud  to  sand. 

Micropteriis  dolomien  Lacepede.  Small-mouthed  Bass 
Meek  records  this  species  as  follows,  ' '  Among  the  waters  covered 
by  this  report,  the  small-mouthed  bass  was  found  only  in  Spirit 
Lake."16  It  has  not  been  recorded  by  the  writer,  but  is  reported  by 
Mr.  Shear  as  occurring  rarely,  through  accidental  introduction  with 
the  large-mouthed  bass.  Every  few  years,  according  to  his  state- 
ment, one  of  this  species  is  caught  here. 

Micropterus  salmoides  (Lacepede).    Large-mouthed  Bass 
This  is  one  of  the  best  and  most  important  game  fishes  of  this 
region.    It  is  tolerably  common  in  the  three  major  lakes.    It  prefers 
the  weedy  portions  of  the  lake,  but  is  not  limited  to  them,  and  may 
be  found  over  different  types  of  bottom. 

Stizoste-dion  vitreum  (Mitchill).  Wall-eyed  Pike;  Pike 
This  is  the  most  important  game  fish  of  the  lakes,  and  occurs  in 
considerable  numbers  in  the  three  major  lakes.  The  State  Fish 
Hatchery  at  Orleans  is  maintained  wholly  for  the  propagation  of 
this  fish.  In  1922,  9,000,000  fry  were  liberated  in  West  Okoboji, 
5,000,000  in  Spirit  Lake,  and  3,000,000  in  East  Okoboji.17  The 
spawning  season  begins  soon  after  the  ice  is  out  of  the  lakes,  the 
fishes  coming  into  shallow  water  near  the  shore  for  this  purpose. 
During  the  summer,  they  migrate  to  deeper  water  where  the  bottom 
is  rocky. 

SUzostedion  canadense  grisewn,  (De  Kay).  Sauger 
The  sauger  has  not  been  taken  by  the  writer  in  this  region,  and 
but  one  specimen,  a  mounted  one  owned  by  its  captor,  Mr.  Harry 
Tennant,  of  Arnold 's  Park,  has  been  examined.  It  is  mentioned  by 
Meek  as  occurring  in  Spirit  Lake,18  and  by  Carfield  in  his  letter  to 
the  State  Game  Warden.    It  is  reported  by  Mr.  Shear  as  tolerably 


is  Meek,  S.  E.  Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska, 
p.  138. 

17  Figures  supplied  by  Dr.  John  H.  Malony,  State  Fish  and  Game  Dept. 

is  Meek,  S.  E.  Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska, 
p.  138. 


FISHES  OF  THE  OKOBOJI  REGION  19 

common  in  the  lakes.    Very  likely  it  is  not  commonly  distinguished 
from  the  other  species. 

Perca  flawescens  (Mitchill).  Yellow  Perch;  Perch 
This  is  the  commonest  and  most  widely  distributed  of  all  the  fishes 
in  the  lakes.  It  is  found  under  a  variety  of  conditions  of  bottom, 
from  mud  as  in  North  Hottes  to  sandy  as  in  Spirit  Lake,  and  from 
shallow  water  one  and  one  half  meters  to  nearly  twenty-seven  meters 
(eighty-seven  feet)  in  Emerson  Bay  of  West  Okoboji.  It  may  also 
be  found  in  or  near  the  growth  of  water  weeds  or  away  from  them. 
It  attains  its  largest  size  in  Spirit  Lake.  A  young  individual,  40 
mm.  long,  was  taken  in  Thomas  Creek,  July  20,  1922. 

Peroina  caprodes  (Rafinesque) .  Sand  Darter ;  Log  Perch 
This  species  is  found  on  sandy  or  gravelly  bottom  in  shallow 
water.  It  is  abundant  in  Spirit  Lake,  where  it  was  seined  most  com- 
monly in  water  from  one  to  one  and  one  half  meters  deep.  It  was 
not  taken  in  East  Lake,  although  it  probably  occurs  there.  Only 
one  specimen  was  taken  in  the  West  Lake.  This  was  seined  along 
the  Sand-bar  by  Messrs.  D.  T.  Jones  and  G.  E.  Potter,  August  12, 
1924. 

Boleosoma  nigrum  (Rafinesque).  Johnny  Darter 
Meek  records  this  species  from  both  East  Okoboji  and  Spirit 
Lakes.  "A  specimen  was  found  in  a  minnow  basket  at  Spirit  Lake 
where  it  seems  to  be  used  as  live  bait  to  some  extent. ' ,19  It  was  not 
taken  by  the  writer  in  the  lakes  but  was  seined  in  the  Little  Sioux 
River  in  the  summers  of  1924  and  1925. 

Etheostoma  iowce  Jordan  and  Meek.  Iowa  Darter 
Meek  collected  this  species  in  Spirit  Lake,  but  gives  no  data  con- 
cerning it.20  The  writer  has  not  collected  it  personally  but  has  in 
his  possession  six  specimens  collected  by  Mr.  Hopkins  in  Spirit 
Lake,  May  12,  1926.  He  states  that  he  has  seen  this  species  in  late 
spring  or  early  summer  in  East  Okoboji  Lake,  in  shallow  water  over 
sand  between  the  weeds  and  the  shore. 

Roccus  chrysops  (Rafinesque).    Silver  Bass;  White  Bass 
This  is  a  common  species  in  both  East  and  West  Lakes,  less  so  in 
Spirit  Lake.    On  June  26,  1922,  200  were  taken  in  the  seine  in  East 


is  Meek,  S.  E.    Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska, 
p.  138. 
20X00.  dt. 


20 


IOWA  STUDIES  IN  NATURAL  HISTORY 


TABLE  I 
Summary  of  Distribution 


Ldttle 

West 

East 

Reed 

Thomas  Sioux 

Species 

Okoboji  Okoboji 

Spirit 

Hottes 

Creek 

Creek      River 

P.  spathula 

X? 

X? 

L.  osseus 

X 

X 

X 

L.  platystornus 

X 

X 

X 

H.  alsoides 

X 

C.  namaycush 

X? 

? 

X? 

I.  eyprinella 

X 

X 

X 

X 

I    bubalus 

X 

X 

X 

Carpiodes  carpio 

X 

C.  commersonii 

X 

X 

X 

X 

M.  aureolum 

X 

X 

X 

Cyprinus  carpio 

X 

X 

X 

X 

H.  nuchalis 

X 

P.  notatus 

X 

X 

X 

X 

S.  atromaculatus 

X 

X                      X 

A.  crysoleucas 

X 

X 

X 

X 

C.  vigilax 

X 

X 

X 

N.  cayuga 

X 

X 

N.  heterodon 

X 

X 

N.  blennius 

X 

X 

X                     X 

N.  hudsonius 

X 

X 

X 

N.  lutrensis 

X 

X 

X 

N.  jejunus 

X 

R.  atronasus 

X 

X 

H.  storerianus 

X 

X 

I.  punctatus 

X 

X 

f 

X 

A.  natalis 

X 

X 

X 

A.  nebulosus 

X 

X 

X 

X 

A.  melas 

X 

X 

X 

X 

L.  olivaris 

X 

X 

E.  lucius 

X 

X 

X 

X 

F.  diaphanus 

X 

X 

X 

X 

E.  inconstans 

xf 

P.  guttatus 

X 

X 

P.  annularis 

X 

X 

X 

P.  sparoides 

X 

X 

X 

A.  rupestris 

X 

X 

X 

A.  cyanellus 

X 

X 

X 

L.  megalotis 

X 

X 

L.  humilis 

X 

L.  pallidus 

X 

X 

X 

E.  gibbosus 

X 

X 

X 

X 

M.  dolomieu 

X 

M.  salmoides 

X 

X 

X 

S.  vitreum 

X 

X 

X 

S.  canadense 

X 

X 

P.  flavescens 

X 

X 

X 

X 

X 

1 

P.  caprodes 

X 

X 

X 

B.  nigrum 

X 

X 

X 

E.  iowae 

X 

X 

R.  chrysops 

X 

X 

X 

A.  grunniens 

X 

X 

X 

Totals 

36 

40 

33 

10 

5 

3             14 

PISHES  OF  THE  OKOBOJI  REGION 


21 


TABLE  II 
Summary  of  Habitat  of  Lake  Fishes 


Species 

Mud 

Sand 

Rock 

Open 

Weedy 

P.  spathula 

X 

L.  osseus 

X 

X 

X 

L.  platystomus 

X 

X 

X 

C.  namaycush 

X 

I.  eyprinella 

X 

X 

0.  commersonii 

X 

X 

Cyprinus  carpio 

X 

X 

P.  notatus 

X 

X 

A.  crysoleucas 

X 

X 

C.  vigilax 

X 

X 

X 

X 

N.  cayuga 

X 

X 

X 

X 

N.  heterodon 

X 

X 

X 

X 

N.  blennius 

X 

X 

N.  hudsonius 

X 

X 

X 

N.  lutrensis 

X 

X 

I.  punctatus 

X 

X 

A.  natalis 

X 

X 

X 

A.  nebulosus 

X 

X 

X 

A.  melas 

X 

X 

X 

L.  olivaris 

X 

X 

E.  lueius 

X 

X 

X 

X 

F.  diaphanus 

X 

X 

X 

E.  inconstans 

X 

X 

P.  guttatus 

X 

X 

P.  annularis 

X 

X 

X 

X 

P.  sparoides 

X 

X 

X 

X 

A.  rupestris 

X 

X 

X 

X 

A.  cyanellus 

X 

X 

X 

L».  megalotis 

X 

X 

L.  pallidus 

X 

X 

X 

X 

E.  gibbosus 

X 

X 

X 

M.  salmoides 

X 

X 

X 

X 

S.  vitreum 

X 

X 

P.  flavescens 

X 

X 

X 

X 

X 

P.  caprodes 

X 

X 

B.  nigrum 

X 

X 

E.  iowse 

X 

X 

R.  chrysops 

X 

X 

X 

X 

A.  grunniens 

X 

X 

X 

Totals 

26 

20 

8 

29 

26 

Okoboji  near  the  outlet  of  Spirit  Lake  in  water  from  one  to  two 
meters  deep  over  sandy  bottom.  Later  in  the  season  they  prefer 
somewhat  deeper  water,  under  different  conditions  of  bottom.  On 
July  20, 1922,  they  were  caught  in  abundance  in  water  three  to  four 
meters  deep,  over  a  muddy  bottom.  They  were  also  being  caught 
near  a  rocky  point  at  the  outlet  of  East  Okoboji  into  the  Upper  Gar 
Lake,  where  the  water  was  six  or  seven  meters  deep. 


22  IOWA  STUDIES  IN  NATURAL  HISTORY 

Aplodinotus  grvmmens  Rafinesque.  Sheepshead ;  Fresh-water  Drum 
The  sheepshead  is  common  in  East  and  West  Okoboji  Lakes,  but 
is  rather  rare  in  Spirit  Lake.  It  was  not  recorded  elsewhere.  It  is 
found  more  commonly  in  moderate  depths  over  both  muddy  and 
rocky  bottom. 

The  observations  regarding  the  distribution  and  habitat  of  the 
fishes  of  this  region  are  summarized  in  Tables  I  and  II.  The  occur- 
rence of  the  species  is  indicated  by  the  letter  "x".  Species  marked 
"x?"  have  occured  here  but  are  doubtfully  present  now.  Those 
marked  "  V  may  occur  but  have  not  been  found  or  reported  and 
are  not  included  in  the  totals.  Table  II  includes  only  those  lake 
fishes  for  which  definite  data  were  obtained.  These  observations  ap- 
ply to  the  summer  season  only. 

THE  FISHES  OF  REED  AND  THOMAS  CREEKS 

On  the  east  side  of  East  Okoboji  Lake  are  two  small  creeks  which 
now  into  the  lake  within  a  half  mile  of  each  other.  These  will  be 
designated  as  Thomas  and  Reed  Creeks  respectively,  the  names  given 
to  them  in  the  past  from  owners  of  the  adjoining  land.  These  creeks 
resemble  each  other  in  their  physical  features,  so  that  a  common 
description,  in  the  main,  will  serve  for  the  two.  Both  are  small 
creeks  with  bottoms  mainly  of  silt  with  some  intermixture  of  sand. 
They  are  narrow  and  shallow  with  occasional  deeper  pools  and  with 
slightly  developed  riffles  in  places  where  the  flow,  otherwise  rather 
sluggish,  becomes  moderately  fast.  Near  the  lake,  the  creeks  flow 
through  a  wooded  tract  in  which  the  dominant  type  of  tree  is  the 
bur  oak,  Quercus  macrocarpa.  Of  the  two,  Thomas  Creek  is  the 
larger,  with  larger,  deeper,  and  more  numerous  pools,  and  with  a 
more  rapid  current.  Just  before  entering  the  woods,  this  creek  is 
fed  by  four  springs. 

This  latter  creek  was  first  visited  by  the  writer  in  the  summer  of 
1921.  During  the  seasons  of  1922  and  1924,  both  creeks  were  visited 
and  collections  made,  temperature  taken,  and  samples  of  the  water 
taken.  In  1922,  the  samples  were  tested  by  the  Winkler  method  for 
their  oxygen  content  by  Mr.  Wesley  Damerow.  In  1924,  others 
were  tested  by  Miss  Josephine  Bockwoldt  for  the  hydrogen  ion  con- 
centration. These  tests  indicate  a  high  hydrogen  ion  concentration. 
It  seems  probable  that  this  may  be  accounted  for  by  the  boggy 
ground  through  which,  for  a  part  of  their  course,  the  creeks  flow. 
The  results  of  these  tests  as  well  as  the  temperature  reading  and  the 
weather  conditions  are  given  in  Table  III. 


FISHES  OF  THE  OKOBOJI  EEGION 


23 


TABLE  III 

A 

..     Reed  Creek 

Air 

Water 

H.  ion 

Date 

Time 

Weather 

Wind 

temp. 

temp. 

O  cont. 

cone. 

7/20/22 

1:15  P.M. 

Fair 

Light,  S. 

* 

* 

6.70 

8/2/22 

9:30  A.M. 

Clear 

Calm 

29°C. 

17°C. 

8/12/22 

11:10  A.M. 

Clear 

Light,  S. 

29°C. 

21°C. 

9.38* 

8.98 

7/28/24 

11:15  A.M. 

Clear 

Light,  S.  E. 

31  °C. 

18°C. 

5.32. 

8/4/24 

9:45  A.M. 

Clear 

Light,  S. 

29°C. 

16°C. 

4.7& 

8/12/24 

2:00  P.M. 

Clear 

Light,  N.  E. 

26°C. 

19°C. 

8/14/24 

3:20  P.M. 

Hazy 

Strong,  S. 

28.5°C. 

20.5°C. 

B. 

Thomas  Creek 

Air 

Water 

H.  ion 

Date 

Time 

Weather 

Wind 

temp. 

temp. 

Q  cont. 

cone. 

7/20/22 

2:30  P.M. 

Fair 

Light,  S. 

* 

** 

7.63 

8/4/24 

10:00  A.M. 

Clear 

Light,  S. 

28°C. 

22°C. 

4.76 

8/12/24 

2:30  P.M. 

Clear 

Light,  N.  E. 

25°C. 

23°C. 

8/14/24 

3:55  P.M. 

Hazy 

Strong,  S. 

27°C. 

22°C. 

*  Thermometer  broken 
**  Two  samples  taken 


The  fish  found  in  the  two  creeks  were  nearly  identical.  Four 
species  were  recorded  from  both  and  a  fifth  one  from  Reed  Creek, 
In  both  the  main  species  were  the  creek  chub,  Semotilus  atromacu- 
latus,  the  black-nosed  dace,  RlimictJiys  atronasus,  and  the  straw- 
colored  minnow,  Notropis  bhnnius.  An  immature  perch,  Perca 
flavescens,  40  mm.  long,  was  taken  in  Thomas  Creek  about  three 
fourths  of  a  mile  from  the  mouth.  Mr.  Hopkins  has  taken  adult 
perch  in  Reed  Creek  near  the  mouth,  in  the  spring  when  the  water 
was  high,  and  it  probably  comes  into  the  other  creek  under  similar 
conditions.  Mr.  Hopkins  also  has  taken  the  brook  stickleback,  Euca- 
lia  inconstans,  in  past  years  from  Reed  Creek.  The  writer  has  no 
evidence  whether  or  not  it  still  occurs  here.  The  distribution  of  the 
fishes  in  the  two  creeks  was  similar.  The  great  majority  of  the 
creek  chub  and  the  black-nosed  dace  was  found  in  the  deeper  pools 
where  they  could  find  shelter  under  the  overhanging  shelves  formed 
by  the  grasses  and  other  herbaceous  plants,  or  by  the  roots  of  ad- 
joining trees.  The  straw-colored  minnows  showed  a  preference  for 
the  swifter  waters  of  the  creek,  and  were  frequently  observed  in  or 
near  the  riffles,  although  a  few  were  taken  in  the  pools  with  the 
other  two  species.  Of  the  three,  the  creek  chub  was  the  most  num- 
erous, the  black-nosed  dace  next  in  abundance,  with  the  straw- 
colored  minnow  the  least  common. 


24  IOWA  STUDIES  IN  NATURAL  HISTORY 

The  food  of  seventeen  fishes  from  Reed  Creek  was  studied.  Of 
these,  thirteen  were  ereek  chubs,  three  were  straw-colored  minnows, 
and  the  remaining  one  a  black-nosed  dace.  The  results  are  sum- 
marized in  Table  IV. 

TABLE  IV 

Food  of  Seventeen  Fishes  from  Reed  Creek 

Total  length  in  mm.  Water  Clado-  Cope-  Cray-    Insects       Hydra- 

Species  No.  Mn.  Mx.     Av.    Algae  Weed    cera    poda  fish  Larva  Adult  carina 

S.  atromaculatus  13       25     91     46.1     0.66     1.3  5     35.4    57.5      * 

B.  atronasus  1  73.0  12.0    88.0 

N.  blennius  3**    24    45     36.6  Traces  1.5    0.5  95.0      3.0 

*  One  individual  was  found  in  the  thirteen  fishes  examined 
**  One  with  stomach  and  intestines  nearly  empty;   remaining  contents  un- 
identifiable ;  percentages  based  on  two  specimens 

The  food  of  the  creek  chub,  as  indicated  in  the  table,  consisted 
largely  of  insects,  92.8%  in  all.  Of  the  thirteen  studied,  three  had 
eaten  only  adult  insects,  and  in  two  others,  these  formed  96%  and 
98!%  respectively.  The  insects  eaten  were  almost  wholly  either 
aquatic  coleoptera,  mainly  Gtjrinidce,  or  water-boatmen,  Corixa  sp. 
One  individual,  not  of  the  five  mentioned,  had  eaten  a  grasshopper. 
Insect  larvae  constituted  all  the  food  in  one  specimen,  and  90%  and 
97%  respectively  in  two  others.  Fully  90%  of  these  were  chiron- 
omid  larvae,  the  remainder  consisting  of  other  dipterous  larvae  and 
the  nymphs  of  water-boatmen.  Another  individual  had  eaten  cray- 
fish and  also  some  filamentous  algae,  Yaucheria. 

Forbes  and  Richardson  speak  of  this  fish  as  having  ' '  an  unusually 
varied  diet  for  a  minnow,  including  considerable  quantities  of  vege- 
table food  on  the  one  hand  and  small  fish  on  the  other.  A  fourth  of 
the  food  of  twenty-two  specimens  consisted  of  algae  and  of  miscel- 
laneous vegetable  debris.  Four  of  the  specimens  had  eaten  little 
else  than  filamentous  algae,  and  three  had  captured  small  fishes. 
Grasshoppers,  caterpillars,  ants,  chrysomelid  and  searabaeid  beetles, 
and  various  other  terrestrial  insects  together  with  Corisa,  dipterous 
larvae,  and  other  aquatic  forms,  were  the  insects  represented,  and 
three  of  the  twenty-two  specimens  had  eaten  only  crayfishes/'21 
Everman  and  Clark  state  "the  principal  food  of  the  chub  consists 
of  insect  larvae,  aquatic  insects,  worms,  and  small  crustaceans.7722 

The  numbers  of  the  other  two  species  are  in  themselves  too  small 


si  Forbes,  S.  A.  and  Richardson,  R.  E.    Fishes  of  Illinois,  p.  123. 
22  Evermann,  B.  W.  and  Clark,  H.  W.     Lake  Maxinkuckee,  a  Physical  and 
Biological  Survey,  vol.  1,  p.  346. 


FISHES  OF  THE  OKOBOJI  REGION  25 

for  definite  conclusions.  In  the  case  of  one  of  these,  Notropis  bien- 
nis, other  data  are  available,  which  tend  to  confirm  the  result  ob- 
tained by  the  writer.  Forbes  and  Richardson  state,  * i  from  the  little 
that  is  known  of  its  feeding  habits,  its  food  is  no  more  peculiar  than 
its  general  appearance,  consisting  of  a  mixture  of  aquatic  insects, 
and  chance  vegetation. '  '23  In  an  earlier  paper  Forbes  gives  the  re- 
sults of  a  study  of  five  of  these  minnows.  Seventy-five  per  cent  of 
the  food  was  animal  matter,  the  remaining  plant,  mainly  grass 
seeds.24  Of  the  former,  insect  larvae  constituted  58%  and  copepods,, 
almost  wholly  Cyclops,  10%. 

These  three  fishes  are  typical  pioneer  fishes  characteristic  of  young- 
streams  such  as  the  two  creeks  studied.  Shelford,  some  years  ago,, 
pointed  out  that  the  creek  chub,  Semotilus  atromaculatus,  is  the 
species  "most  commonly  found  in  the  smallest  streams  and  nearest 
the  headwaters  of  the  larger  streams."25  In  most  cases  the  red- 
bellied  dace,  Chrosomus  erytkrogaster,  which  is  not  found  here,  was 
the  next  one  to  be  found  as  one  went  downstream  from  the  source, 
but  in  some  he  found  the  black-nosed  dace,  RMnichthys  atronasus, 
to  be  the  second  species.  In  one  stream,  too,  the  straw-colored  min- 
now, Notropis  blennius,  was  one  of  six  species  to  be  found  in  the 
first  mile  from  the  source.  In  Reed  and  Thomas  Creeks,  the  range 
of  these  three  species  coincided,  although  the  relative  numbers  of  the 
creek  chub  were  somewhat  greater  in  the  uppermost  pools.  During 
the  two  seasons  the  conditions  under  which  they  lived  were  nearly 
similar.  The  temperature  of  the  water  was  low  especially  in  the 
pools  of  Reed  Creek.  The  oxygen  content  of  the  water  was  high 
with  apparently  a  high  hydrogen  ion  concentration  also.  Stretches 
of  gravel  or  sand,  which  occur  occasionally,  furnish  favorable  spawn- 
ing beds,  and  during  the  summer  there  is  an  abundant  supply  of 
insect  food  which  appears  to  be  the  chief  food  item  at  this  season. 

THE  OKOBOJI  LAKES 

The  Okoboji  Lakes,  products  of  the  Wisconsin  ice  sheet,  include 
three  major  lakes,  Spirit,  East  and  West  Okoboji,  and  several  minor 
ones.  The  West  and  East  Lakes  are  connected  by  a  narrow  channel 
between  the  towns  of  Arnold's  Park  and  Okoboji.    There  is  a  creek 


23  Forbes,  S.  A.  and  Richardson,  R.  E.     Fishes  of  Illinois,  p.  138. 

24  Forbes,  S.  A.     The  Food  of  smaller  Fresh-water  Fishes.     Bull.  Ill,  HI. 
State  Lab.  Nat.  Hist.,  Vol.  I,  p.  65-94,  1883. 

25  Shelford,  V.  E.  Ecological  Succession.    I,  Stream  Fishes.    Biol.  Bull.,  VoL. 
21,  p.  9-25,  1911. 


26 


IOWA  STUDIES  IN  NATURAL  HISTORY 


between  Spirit  Lake  and  East  Lake  through  which  a  small  stream 
of  water  flows,  when  the  level  of  the  former  lake  is  high  enough. 
During  the  summer  seasons  of  1924  and  1925,  there  was  little  or  no 
water  in  this  runway.  These  lakes  drain  through  the  Gar  Lake 
with  which  East  Lake  is  connected,  into  the  Little  Sioux  River.  The 
amount  of  water  which  goes  into  this  river  is  said  to  be  slight  in 
comparison  with  the  amount  lost  from  the  lakes  through  evapora- 
tion. Welch  Lake  to  the  north  of,  and  Center  Lake  to  the  east  of 
West  Okoboji  Lake,  have  poorly  developed  streams  through  which  a 
small  amount  of  water  flows  into  the  latter.  To  the  west  and  north- 
west of  Spirit  Lake  are  five  of  the  minor  lakes,  Little  Spirit,  Hottes, 
Robinson,26  Marble,  and  Sunken.  These  drain  into  Spirit  Lake,  the 
last  four  through  Hottes  Lake.  During  the  seasons  referred  to  be- 
fore, the  level  of  these  four  lakes  was  lowered  so  that  they  are  en- 
tirely cut  off  from  each  other,  and  Hottes  Lake  itself  from  Spirit 
Lake.  The  total  drainage  area  of  the  lakes  is  not  great,  84,500 
acres27  or  132  square  miles.  In  Table  V  the  size  and  depths  of  the 
lakes  are  given.  With  the  exception  of  West  Okoboji,  the  areas  were 
taken  from  the  Iowa  Lake  Bed  Report,  1917  and  the  other  figures 
are  based  on  studies  made  of  the  maps  of  the  State  Highway  Com- 
mission. 


TABLE  V 
Size  and  Depth  of  the  Lakes 


Area 

Length  of 

Volume  in 

Maximum  Mean 

in 

shoreline 

cubic 

depth 

depth 

Name  of  Lake 

acres 

in  miles 

meters 

in  meters 

in  meters 

Spirit 

5660 

18.3 

225,548,000 

7.6 

5.5 

West  Okobojiss 

3788 

18.2 

188,340,000 

40.2 

12.3 

East  Okoboji 

1875 

16.7 

22,687,000 

7.9 

3.0 

Center 

264 

2.6 

3,567,000 

4.5 

3.2 

Welch 

57 

1.4 

344,000 

1.9 

1.5 

Little  Spirit 

724* 

10.4 

5,132,000 

3.7 

2.1 

Hottes 

312 

7.0 

1,758,000 

2.4 

1.4 

Marble 

175 

2.7 

1,058,000 

2.1 

1.5 

*  214  acres  only  in  Iowa,  the  remainder  in  Minnesota. 

Some  years  ago  Shelford  traced  the  ecological  succession  in  sev- 
eral sand-bottomed  ponds  located  in  Indiana  near  the  south  end  of 


26  The  west  portion  of  Hottes  Lake  as  shown  on  maps  23-24,  State  Highway 
Commission,  1915. 

27  Iowa  Lake  Bed  Survey  Report,  1917,  p.  54. 

28  Birge,  E.  A.  and  Juday,  Chancey.    A  Limnological  Reconnaissance  of  West 
Okoboji.     Stud,  in  Nat.  Hist.,  Univ.  of  la.,  Vol.  IX,  No.  1,  p.  5,  1920. 


FISHES  OP  THE  OKOBOJI  EEGION  27 

Lake  Michigan.29  In  the  earliest  stage  the  bottom  was  free  of  plant 
growth.  This  was  followed  by  a  stage  in  which  the  bottom  was 
overgrown  with  Chara,  frequently  associated  with  a  growth  of  bul- 
rushes near  the  edge  of  the  pond.  This,  as  Shelf ord  states,  "pre- 
pares a  way  for  the  vegetation  which  reaches  to  and  above  the  sur- 
face. This,  in  turn,  fills  the  pond  still  further  and  the  strictly 
marsh  vegetation  takes  possession.  The  history  of  the  true  pond  is 
then  at  an  end  and  the  story  of  the  marsh  begins."30 

Some  of  these  ecological  stages  may  be  found  in  the  lakes  of  the 
Okoboji  region.  The  early  bare-bottom  stage  is  nearly  realized  in 
the  case  of  Welch  Lake.  The  bottom  is  mainly  of  silt  with  a  slight 
intermixture  of  sand  along  the  shore.  On  the  west  shore  and  to  a 
lesser  extent  on  the  east  side  the  bottom  is  rocky.  The  slope  is 
gradual,  and  the  greatest  depth  is  not  quite  two  meters.  Filament- 
ous algae  were  noted  on  the  rocks  and  other  objects  in  the  water  but 
no  Chara  was  found,  and  the  aquatic  seed  plants  were  scarcely  rep- 
resented. Phytoplankton  in  which  Microcystis  predominated  was 
very  abundant,  giving  a  greenish  color  to  the  water.  The  fish  fauna 
is  very  limited.  The  bullhead  minnow,  Cliola  vigttax,  was  seined 
by  the  writer  in  great  numbers,  and  several  young  black  bullheads, 
Arneiurus  melas,  were  also  taken.  Mr.  Shear,  who  for  twenty  years 
has  seined  this  lake  for  minnows,  states  that  with  the  exception  of 
an  occasional  pike,  Esox  Indus,  he  has  never  taken  other  than  these 
two  species. 

Another  ecological  stage  much  in  advance  of  Welch  Lake  is  repre- 
sented by  Spirit  Lake.  This  lake,  the  largest  in  the  state,  is  shallow 
in  comparison  with  its  size,  reaching  a  depth  of  only  7.6  meters. 
With  the  exception  of  East  Bay  the  outline  is  very  regular.  The 
shores  are  comparatively  low  so  that  it  is  exposed  to  winds  from  all 
directions.  The  bottom  of  the  shallower  waters  is  chiefly  sandy 
although  gravel,  both  coarse  and  fine,  and  clay  occur.  The  slope  of 
the  bottom  is  very  gradual.  There  are  several  rock  reefs  in  the 
lake,  mainly  in  deeper  water  although  a  few  of  them  reach  the 
shore. 

While  the  amount  of  vegetation  other  than  the  phytoplankton 
and  attached  filamentous  algae  is  relatively  moderate,  well  developed 
growths  of  water  weeds  and  of  rushes  are  found  in  different  portions 


29  Shelford,  V.  E.  Ecological  Succession.     II,  Pond  Fishes.     Biol.  Bull.,  21, 
p.  127-151,  1911. 

so  Shelford,  V.  E.    Animal  Communities  in  Temperate.  America,  p.  151,  1913. 


28  IOWA  STUDIES  IN  NATURAL  HISTORY 

of  the  lake.  The  phytoplankton  in  the  summer  time  becomes  so 
abundant  as  to  form  a  green  scum  on  the  surface  of  the  calm  water. 
Shimek  accounts  for  the  moderate  growth  of  the  higher  plants  by 
the  lack  of  sheltered  bays,  "coupled  with  the  prevailing  sandy  or 
gravelly  shores  and  bottom,  and  the  greater  exposure  of  the  surface 
to  storms."31 

While  earlier  ecological  stages  may  be  found,  the  lake  as  a  whole 
has  reached  the  stage  of  early  maturity.  The  conditions  are  evi- 
dently favorable  for  fish  life,  for  thirty-three  species  representing 
twelve  families  have  been  recorded  from  this  lake.  It  is  extremely 
doubtful,  however,  that  one  of  these,  the  Great  Lake  Trout,  Cristi- 
vomer  namaycush,  is  found  here  at  the  present  time. 

West  Okoboji  Lake  presents  conditions  markedly  different  from 
the  two  lakes  already  discussed,  and  in  the  matter  of  depth  differs 
from  all  of  the  lakes  of  this  region.  Its  mean  depth,  12.3  meters,  is 
greater  than  the  maximum  of  any  other  of  these  lakes,  and  it  reaches 
a  maximum  depth  of  40.2  meters.  West  Okoboji  is  nearly  six  miles 
long,  and  while  it  is  three  miles  across  in  its  widest  portion,  its 
average  width  is  approximately  a  mile.  It  is  not  so  exposed  as 
Spirit  Lake,  its  bank  for  the  most  part  high,  abrupt,  and  wooded, 
although  in  several  places  the  land  slopes  down  to  the  water 's  edge. 
The  outline  of  this  lake  is  irregular.  Three  well  developed  bays 
cut  off  to  a  greater  or  less  extent  by  points  of  land  and  outstretch- 
ing reefs  are  found  on  the  southeast  and  west  shores.  Smaller  bays 
and  coves  also  occur  on  either  side  of  the  lake.  ' '  The  main  slope  of 
the  bottom  of  the  lake  is  fairly  uniform  to  the  depth  of  eighty  feet, 
but  below  that  depth  the  slopes  are  decidedly  steeper. ' ,32 

West  Okoboji  has  attained  the  stage  of  maturity,  although  in  dif- 
ferent localities  other  stages  from  the  bare-bottom  to  that  of  the 
marsh  may  be  found.  More  favorable  conditions  for  aquatic  vege- 
tation are  afforded  in  this  lake  than  in  Spirit  Lake.  The  bottom  is 
not  so  uniformly  sandy  here,  and  there  is  better  protection  from 
wave  action,  especially  in  the  three  bays  referred  to.  Wylie  con- 
cluded from  a  survey  made  of  the  lake  that  about  1100  acres,  about 
30%  of  the  lake,  was  occupied  by  the  larger  plants.  In  most  places, 
he  states,  these  are  submerged  and  do  not  come  to  the  surface.33 


si  Shimek,   Bohumil.     The  Plant   Geography  of  the  Lake   Okoboji  Region. 
Bull,  from  Lab.  Nat.  Hist.,  Univ.  la.,  Vol.  VII,  No,  p.  5,  1915. 

32  Birge,  E.  A.  and  Juday,  Chancey.    A  Limnological  Reconnaissance  of  West 
Okoboji.     p.  5. 

33  Wylie,  R.  B.    The  Major  Vegetation  of  Lake  Okoboji.    Proc.  la.  Acad.  Sci., 
Vol.  27,  p.  91-97,  1920. 


FISHES  OF  THE  OKOBOJI  REGION  29 

The  growth  of  phytoplankton  becomes  conspicuous  from  midsum- 
mer on,  but  not  so  marked,  however,  as  that  found  in  Spirit  Lake. 

A  slightly  larger  number  of  fishes,  thirty-six,  has  been  recorded 
from  this  lake.  This  number  includes  again  the  Great  Lake  trout 
which  has  been  planted  in  the  lake  with  doubtful  success.  The  great 
majority  of  fishes,  both  of  species  and  individuals,  are  found  in  the 
bays  in  the  vicinity  of  the  water  weeds. 

East  Okoboji  is  a  long  narrow  lake,  nearly  seven  miles  in  length, 
and  averaging  about  one  half  a  mile  in  width.  It  is  irregular  in 
outline  and  generally  has  high  banks,  many  of  them  wooded.  The 
lake  is  shallow  with  a  maximum  depth  of  7.9  meters,  and  an  average 
of  3.0  meters.  This  lake  with  its  abundant  growth  of  aquatic  vege- 
tation represents  a  stage  of  maturity  in  advance  of  the  West  Lake. 
Forty  species  of  fish  have  been  recorded  from  this  lake. 

The  most  advanced  ecological  stage  which  is  represented  here  is 
found  in  the  small  shallow  lakes,  Marble,  Hottes,  and  Robinson. 
The  last  named  with  which  the  author  is  most  familiar  will  be  used 
to  illustrate  this  stage.  When  first  visited,  in  1922,  Robinson  Lake 
was  about  one  and  one  half  miles  long  and  half  a  mile  wide.  It  was 
very  shallow,  the  greatest  depth  then  less  than  two  meters.  The 
bottom,  soft  and  mostly  clay,  with  some  sandy  silt,  was  largely 
covered  with  a  rich  growth  of  water  weeds.  In  some  parts  of  the 
lake  patches  of  rushes  occurred.  Six  species  of  fish  were  taken  in 
this  lake.  During  the  next  three  years  the  rainfall  was  so  greatly 
reduced  that  the  level  of  all  the  lakes  was  greatly  lowered.  Robin- 
son and  the  adjoining  shallow  lakes  were  in  danger  of  drying  up 
completely  and  the  fish  life  nearly,  if  not  completely,  exterminated. 
About  twenty  years  ago  under  similar  conditions,  so  the  writer  was 
informed,  these  lakes  became  dry.  They  are  in  the  stage  of  old  age, 
and  are  so  shallow  that  they  do  not  have  sufficient  volume  of  water 
to  withstand  a  series  of  dry  seasons. 

GENERAL  DISCUSSION 

The  results  obtained  from  these  studies  indicate  that  a  large 
number  of  species  prefer  a  habitat  in  or  near  the  growths  of  water 
weeds.34  Of  the  forty-five  species  listed  from  the  lakes  here,  twenty- 
six  are  found  there  all  or  part  of  the  time,  while  twelve  show  a 
preference  for  open  water.  The  writer  has  no  data  for  the  remain- 
ing seven  species.    Wylie,  in  his  survey  of  the  vegetation  of  Lake 


34  Fotamogetons,  Myriophyllum,  and  Ceratophyllwm  are  the  dominant  types. 


30  IOWA  STUDIES  IN  NATURAL  HISTORY 

Okoboji,  made  the  following  observation:  "During  the  entire 
month  given  to  this  survey,  and  during  which  time  hundreds  of 
people  were  observed  fishing  in  various  parts  of  Lake  Okoboji,  no 
fish  were  being  caught  except  in  or  along  the  edge  of  these  masses 
of  major  vegetation."35  There  are  two  evident  advantages  derived 
from  a  habitat  among  the  aquatic  plants.  In  the  first  place,  it  af- 
fords a  wide  range  of  food  possibilities,  and  secondly,  it  provides 
excellent  shelter.  Predaceous  species  as  the  Pike,  Esox  lucius,  con- 
cealed by  vegetation,  lie  in  wait  for  their  prey.  Other  species  as 
the  carp,  Cyprinus  cwpio,  lay  their  eggs  in  such  places,  and  the 
nests  of  the  sunfishes  may  be  found  in  shallow  water  near  the  shore 
among  the  water  plants.  While  the  differences  in  the  numbers  of 
species  recorded  from  the  three  major  lakes  are  not  large  enough 
to  be  significant,  yet  it  is  interesting  to  note  that  their  order  coin- 
cides with  the  relative  amount  of  vegetation  found.  Thus  Spirit 
Lake  with  a  moderate  amount  of  vegetation  has  thirty-three  species 
of  fishes,  West  Okoboji  with  a  large  amount,  thirty-six  species,  and 
East  Okoboji  with  relatively  the  greatest  amount,  has  forty. 

Robinson  Lake  with  a  proportionately  greater  growth  of  vegeta- 
tion than  East  Okoboji,  might  be  expected  to  have  a  greater  number 
of  species  than  the  latter,  but  only  six  species  were  taken  there.36  The 
most  conspicuous  difference  between  the  two  is  that  of  depth,  Robin- 
son having  a  maximum  depth  of  1.6  meters  while  that  of  East  Oko- 
boji was  7.9  meters.  While  the  difference  in  depth  may  be  a  factor  in 
accounting  for  the  greater  number  of  species  in  the  one  than  in  the 
other,  it  seems  probable  that  other  factors  are  more  concerned. 
The  oxygen  content  of  the  water  is  probably  favorable,  for  two 
samples  taken  from  different  parts  of  the  lake  on  August  12,  1922, 
gave  5.07  and  5.22  ec.  per  liter.  Another  sample  taken  July  28, 
1924,  and  tested  for  the  hydrogen  ion  concentration,  gave  a  pH  of 
5.71.  This  degree  of  acidity  is  probably  an  important  factor  in 
limiting  the  number  of  species.  Possibly  the  high  temperature  of 
the  lake  at  times  during  the  summer  is  another  factor.  On  July  27, 
1922,  at  2:15  P.  M.,  the  surface  temperature  near  the  shore  was 
thirty-one  degrees,  C,  one  degree  cooler  than  the  air,  and  on  August 
14,  1924,  at  2:20  P.  M.,  the  same  temperature  was  noted  with  an 
air  temperature  of  twenty-seven  degrees,  C.    Three  of  the  species 


35  Wylie,  R.  B.     The  Major  Vegetation  of  Lake  Okoboji.     Proc.  la.  Acad. 
Sci.,  Vol.  27,  p.  97,  1920. 

36  These  and  the  following  statements  apply  to  conditions  in  1922. 


FISHES  OF  THE  OKOBOJI  REGION  31 

found  in  this  lake  occurred  in  great  numbers,  namely,  the  black 
bullhead,  Ameiurus  melas,  the  long-eared  sunfish,  Lepomis  megalatis, 
and  the  common  sunfish,  Eupomotis  gibbosus.  Two  others,  the 
perch,  Perca  flavescens,  and  the  golden  shiner,  Abramis  crysoleucas, 
were  tolerably  common,  and  the  pike,  Esox  lucius,  was  found  in 
lesser  numbers.  Evidently  the  conditions  were  favorable  for  these 
fishes,  but  were  not  the  kind  preferred  by  other  species,  for  oppor- 
tunity in  the  past  has  been  given  them  to  enter  this  lake  at  the  time 
of  high  water  when  Robinson,  Hottes,  and  Marble  Lakes  were  con- 
nected with  each  other  and  with  Spirit  Lake. 

Under  certain  conditions  of  weather  the  oxygen  content  of  Spirit 
Lake  apparently  becomes  so  reduced  as  to  make  conditions  for  the 
fishes  most  unfavorable.  Under  ordinary  conditions  the  oxygen 
supply  is  kept  up  in  part  by  photosynthesis  in  the  water  plants  and 
in  part  by  wave  action.  Exposed  as  it  is  on  all  sides,  the  surface 
for  the  most  part  is  kept  in  motion  and  the  oxygen  distributed.  The 
lake  is  too  shallow  for  stratification  during  the  summer  and  from 
the  meager  data  available,  the  temperature  and  oxygen  content  ap- 
pear to  vary  but  little  from  the  surface  to  the  bottom  under  ordin- 
ary conditions. 

For  three  or  four  days  ending  August  6,  1922,  calm  weather  pre- 
vailed with  high  temperature.  On  the  6th,  Dr.  J.  H.  Malony  re- 
ported that  the  wall-eyed  pike,  Stizostedion  vitreum,  were  dying  in 
great  numbers  in  Spirit  Lake  and  the  perch,  Perca  flavescens,  and 
the  shiner,  Notropis  Jiudsonius,  had  suffered  but  not  to  such  a 
marked  extent.  Specimens  of  the  first  two  species  were  examined 
but  nothing  abnormal  was  discovered.  On  the  7th,  when  the  writer 
visited  the  lake,  a  strong  northwest  wind  was  blowing  and  the  lake 
was  too  rough  to  venture  out  on  it.  Larger  fishes  than  those  ex- 
amined on  the  preceding  day  were  washed  in  together  with  great 
numbers  of  smaller  ones.  Among  them,  black  bullheads,  Ameiurus 
melas,  eight  or  ten  inches  long  were  noted.  The  number  of  dead 
fishes  washed  in  decreased  during  the  day  until  in  the  afternoon  it 
was  apparent  that  no  more  fish  were  dying. 

Dr.  G-.  M.  Smith,  who  visited  the  lake  on  the  morning  of  the  7th, 
came  to  the  conclusion  that  decomposition  of  algae  was  responsible 
for  the  death  of  the  fishes.  Exposure  to  the  sun  during  the  calm 
days  had  killed  the  phytoplankton  so  extensively  that  its  decay  in 
the  water  had  consumed  much  of  the  oxygen  present.  At  the  same 
time  the  high  temperature  of  the  water  during  this  period  would 


32  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

also  tend  to  diminish  the  oxygen.  It  seems  probable  that  the  oxygen 
was  so  reduced  during  the  period  of  calm  ending  the  6th,  as  to  suf- 
focate the  fish. 

On  the  8th,  the  writer  accompanied  Professor  F.  A.  Stromsten 
and  Mr.  Wesley  Damerow  to  this  lake  where  temperatures  at  differ- 
ent depths  were  taken  with  an  electric  resistance  thermometer  and 
samples  of  water  taken  for  determination  of  the  oxygen  content. 
The  results  are  given  in  the  following  table. 

TABLE  VI 

Temperature  Readings  and  Oxygen  Content,  Spirit  Lake 

Midway  between  Templar's 

Park  and  Red  Nose  Point  East  of  Templar's  Park 

9:30  A.M.  2:30  P.M. 

Depth                  Temp.         0  cc.  per  liter  Temp.            0  cc.  per  liter 


0  m. 

21.88°C. 

5.61 

23.50°C. 

7.92 

1  m. 

21.80°C. 

5.84 

22.00°C. 

2  m. 

21.85°C. 

5.47 

21.55°C. 

3  m. 

21.80°C. 

5.28 

21.39°C. 

4.99 

4  m. 

21.75°C. 

5.62 

21.30°C. 

5  m. 

21.60°C. 

5.85 

21.20°C. 

6  m. 

21.00°C. 

3.67 

It  will  be  noted  that  the  temperature  varied  but  little  from  the 
surface  to  the  bottom,  and  that  the  oxygen  supply  was  evidently 
ample.  It  seems  probable  that  the  oxygen  supply,  which  had  been 
diminished  in  the  ways  mentioned,  was  restored  to  normal  by  the 
gale  on  the  7th.  This  stirred  up  the  lake  so  that  the  oxygen  was 
mixed  with  the  water,  and  viable  conditions  once  more  established 
for  the  fishes.  A  similar  occurrence  under  like  conditions  took 
place  in  early  July  1921,  but  with  less  fatality  to  the  fishes. 

The  number  of  species  found  in  the  Little  Sioux  River  was  much 
less  than  the  number  in  the  major  lakes.  Only  twelve  species  were 
found  in  the  river  as  compared  with  forty-five  in  the  three  lakes 
together.  This  is  quite  in  accord  with  the  observations  of  Pearse 
who  states,  "rivers,  at  least  in  summer,  contain  fewer  fishes  per 
unit  of  area  than  lakes.  For  fishes  a  river  is  a  highway  and  a  refuge. 
It  gives  access  to  the  stores  of  food  in  swamps  and  lakes,  and  in 
winter  furnishes  an  environment  which  is  fairly  stable.  However, 
a  river  is  not  capable  of  producing  much  fish  food  within  itself. 
The  food  resources  available  to  lake  fishes  in  the  bottom  mud  can- 
not occur  in  quantity  in  rivers  because  the  bottom  is  continually 
changing. '  '37 


37  Pearse,  A.  S.     The  Distribution  and  Food  of  the  Fishes  of  Three  Wiscon- 
sin Lakes  in  Bummer.    Univ.  Wis.  Stud,  in  Sci.,  No.  3,  p.  53,  Madison,  1921. 


FISHES  OP  THE  OKOBOJI  REGION  33 

It  will  be  noted,  however,  that  Robinson  Lake  had  but  half  the 
number  of  species  found  in  the  Little  Sioux  River,  again  indicating 
that  the  conditions  in  that  lake  were  not  favorable  for  a  large  num- 
ber of  species. 

SUMMARY 

Fifty-one  species,  possibly  fifty-two,  distributed  among  seven 
orders,  fifteen  families,  and  thirty-seven  genera  were  recorded 
from  the  Lake  Okoboji  region.  Of  these,  forty-five  species  were 
listed  from  the  lakes,  fourteen  from  the  Little  Sioux  River,  and  five 
from  Reed  and  Thomas  Creeks.  Two  species,  the  small-mouth  buf- 
falo, Ictiobus  bubalus,  and  the  small-mouthed  bass,  Micropterus 
dolomieu,  which  were  recorded  by  Meek,  have  not  been  taken  by  the 
writer.  In  the  case  of  two  other  species,  the  spoonbill,  Polyodon 
spathula,  and  the  Great  Lake  trout,  Cristivomer  namaycush,  the 
writer  has  no  conclusive  evidence  to  indicate  whether  or  not  they 
still  occur  in  the  lakes. 

Observations  were  made  regarding  the  summer  habitat  of  thirty- 
eight  species.  Twelve  were  found  to  have  a  preference  for  muddy 
bottom,  nine  for  sandy,  and  two  for  rocky.  Nine  species  were  found 
on  both  muddy  and  sandy  bottoms,  four  on  both  muddy  and  rocky, 
one  on  both  sandy  and  rocky,  and  another  one  was  found  on  all 
three.  Twenty-six  species  were  found  among  aquatic  vegetation, 
nine  practically  all  the  time  and  the  remaining  seventeen  part  of 
the  time.  Twelve  showed  a  decided  preference  for  open  water.  The 
preference  for  vegetation  is  presumably  due  to  the  abundance  and 
variety  of  the  food  supply  found  there  and  to  the  shelter  afforded 
by  it. 

During  the  summer  season  Reed  and  Thomas  Creeks  are  narrow 
and  shallow  with  occasional  deeper  pools  and  slightly  developed 
riffles.  Five  species  were  listed  from  these  creeks.  Three  of  these, 
named  in  the  order  of  the  numbers  found,  the  creek  chub,  SenuotUus 
atrorrmcidatus,  the  black-nosed  dace,  RMnichtlvys  atronasus,  and  the 
straw-colored  minnow,  Notropis  blennius,  constituted  the  main  fish 
life  of  both  creeks.  An  immature  perch,  Perca  flavescens,  was  tak- 
en in  Thomas  Creek.  Adults  of  this  species  occur  in  the  spring 
during  high  water  in  Reed  Creek  and  very  likely  would  be  found  in 
Thomas  Creek  under  similar  conditions.  The  brook  stickleback, 
Eucalia  iiieonstans,  has  been  taken  in  years  past  in  Reed  Creek. 
Whether  or  not  it  occurs  there  now  is  uncertain.    The  brook  chub 


34  IOWA  STUDIES  IN  NATUEAL  HISTOEY 

and  the  black-nosed  dace  were  found  mainly  in  the  deeper  pools 
with  overhanging  shelves  of  vegetation  while  the  straw-colored  min- 
now showed  a  preference  for  the  swifter  waters  of  the  creeks.  Dur- 
ing the  two  seasons  when  the  studies  were  made  the  conditions  un- 
der which  these  three  species  lived  were  very  similar.  The  tempera- 
ture of  the  water  was  low,  especially  in  the  pools  of  Eeed  Creek. 
The  water  was  well  oxygenated  and  a  high  hydrogen  ion  concentra- 
tion was  indicated.  The  food,  as  judged  by  the  stomach  contents  of 
seventeen  of  these  fishes,  consists  mainly  of  insects  during  the  sum- 
mer. 

Several  ecological  stages  are  represented  by  the  different  lakes  of 
the  Okoboji  region.  The  earliest  one,  approximating  the  bare-bot- 
tom condition,  is  represented  by  Welch  Lake.  Three  species  of 
fishes  were  listed  from  this  lake.  Successive  stages  of  maturity  with 
increasing  amounts  of  vegetation  are  found  in  Spirit,  West  Okoboji, 
and  East  Okoboji  Lakes.  The  number  of  species  of  fishes  recorded, 
while  not  markedly  different,  increased  slightly  with  the  greater 
amount  of  vegetation,  thirty  three,  thirty-six,  and  forty  species  re- 
spectively in  the  three  lakes.  The  most  advanced  stage  is  found  in 
the  shallow  lakes,  Hottes,  Eobinson,  and  Marble.  Eobinson  Lake, 
taken  as  a  typical  example,  had  but  six  species  although  the  aquatic 
vegetation  was  relatively  greater  than  that  of  East  Okoboji.  The 
acidity  of  the  lake  as  indicated  by  a  pH  of  5.71  has  probably  been  a 
factor  in  limiting  the  number  of  species  here.  The  high  temperature 
of  the  water  at  times  during  the  summer,  at  least  31°  C,  associated 
with  the  extreme  shallowness  of  the  lake  may  be  another  factor. 

Spirit  Lake  at  times  presents  unfavorable  conditions  for  fish  life. 
A  period  of  clear  calm  days  with  high  temperature  appears  to  kill 
the  minute  plants  of  phytoplankton.  By  the  decay  of  these  the 
oxygen  supply  of  the  lake  is  apparently  reduced  to  such  an  extent 
that  great  numbers  of  fish  are  killed.  The  amount  of  oxygen  sup- 
plied to  the  water  through  photosynthesis  is  not  so  great  in  this  lake 
because  of  the  rather  moderate  amount  of  vegetation.  However,  the 
lake  is  so  exposed  that  under  ordinary  conditions  there  is  a  sufficient 
supply  of  oxygen  through  wave  action. 

The  number  of  species  of  fishes  found  in  the  Little  Sioux  River 
was  much  less  than  that  of  the  three  major  lakes.  From  Eobinson 
Lake,  however,  less  than  half  as  many  species  were  recorded  ps  from 
the  river. 


BIBLIOGRAPHY 

Birge,  E.  A.  and- Juday,  C.    A  Limnological  Reconnaissance  of  West  Okoboji. 

Studies  in  Natural  History,  University  of  Iowa,  Vol.  IX,  No.  1,  p.  1-56. 

Iowa  City,  1920. 
Evermann,  B.  W.  and  Clark,  H.  W.     Lake  Maxinkuckee,  a  Physical  and  Bio- 
logical Survey.    2  vols.    Indianapolis,  1920. 
Evermann,  B.  W.  and  Cox,  U.  O.    Report  on  the  Fishes  of  the  Missouri  River 

Basin.     Report  U.  S.  Commisssioner  of  Fish  and  Fisheries,  p.  352-429. 

Washington,  1894. 
Forbes,  S.  A.     The  Food  of  the  Smaller  Fresh- water  Fishes.     Illinois  State 

Laboratory  of  Natural  History,  Bull.  Ill,  Vol.  1,  p.  65-94.    Urbana,  1883. 
Forbes,  S.  A.  and  Richardson,  R.  E.     The  Fishes  of  Illinois.    Natural  History 

Survey  of  Illinois,  Vol.  Ill,  2nd  ed.     Springfield,  1920. 
Iowa  Lake  Bed  Survey  Report.    Des  Moines,  1917. 
Jordan,  D.  S.  and  Evermann,  B.  W.     Fishes  of  North  and  Middle  America. 

U.  S.  Nat.  Mus.  Bull.,  47.     Washington,  1896. 
Jordan,  D.  S.     Fishes.    D.  Appleton  and  Company.    New  York,  1925. 
Kemmerer,  George,  Bouvard,  J.  F.  and  Boorman,  W.  R.     Northwestern  Lakes 

of  the  IT.  S.    Biological  and  Chemical  Studies  with  Reference  to  Possibilities 

in  the  Production  of  Fish.     Bull.  Bureau  of  Fisheries,  Vol.  39,  p.  51-140. 

Washington,  1923. 
Meek,  S.  E.     Notes  on  the  Fishes  of  Western  Iowa  and  Eastern  Nebraska. 

Bull.  U.  S.  F.  C,  14,  p.  133-138.    Washington,  1894. 
Pearse,  A.  S.     The  Distribution  and  Food  of  the  Fishes  of  Three  Wisconsin 

Lakes  in  Summer.    University  of  Wisconsin,  Studies  in  Science,  No.  3,  p. 

1-61.     Madison,  1921. 
Potter,  G.  E.    The  Food  of  the  Short-nosed  Garpike  (Lepidosteus  ylatystomus) . 

la.  Acad.  Sci.,  Vol.  XXX,  p.  167-170.    1923. 
Shelford,  V.  E.    Ecological  Succession.    I,  Stream  Fishes.    Biol.  Bull.,  vol.  21, 

p.  9-25.     1911. 

—  Ecological  Succession.     II,  Pond  Fishes.     Biol.  Bull.,  vol.  21,  p.  127-151. 
1911. 

—  Animal  Communities  in  Temperate  America.    University  of  Chicago  Press, 
Chicago.     1913. 

Shimek,  Bohumil.     The  Plant  Geography  of  the  Lake  Okoboji  Region.     Bull. 

Laboratories  of  Natural  History,  University  of  Iowa,  Vol.  VII,  No.  2. 

Iowa  City,  1915. 
Wylie,  R.  B.    The  Major  Vegetation  of  Lake  Okoboji.     Proc.  la.  Acad.  Sci., 

Vol.  27,  p.  91-97.    1920. 


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