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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

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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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APHIS KUMICIS

37

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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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AUG.

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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

) c

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

^||;;^f|MypJ||;

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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

£ ft

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Geol.

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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-

+

+

+
+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+
+

+

+
+

+
+

+

+

+

+

+

+

+

+

+

+

+'

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+
+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+
+

+
+

+

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

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+
+

+
+
+

+

+

+

+

+

+

+

+

+

+

+

+

+

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

P

2.
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r -;;.,,

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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.

BIBLIOGRAPHY

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The sensory reactions in H. swrinamensis. Zool. Jahrb. Abt.
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Multiplication by fission in Holothuria. Amer. Nat. 51, pp.
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On some cases of multiplication by fission etc. Papers from Dr.
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L.

A quantitative study of H. atra Jaeger and the re-establishment
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Variation, Development and Growth in J3". floridana Pourt.,
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28

HOLOTHUBIANS OF BARBADOS AND ANTIGUA 29

Fisher W. K.
1907

Forskaal P.
1775

Greef B.

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Heilprin A.

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Marenzeller E
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The Holothurians of the Hawaiian Islands, Proc. IT. S. Nat.
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Descriptions animaliuxn quae in itinere orientali observavit P.
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Echinodermen, beobachtet auf eine Beise nach der Guinea Insel
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Contribution to the Natural History of the Bermuda Islands.
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Note preliminaire sur les Holothuries provenant des dragages du
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Dragages profondes executes a bord du "Caudan" ' dans le
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Be*sultats scientifique de la campagne du "Caudan" dans le
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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
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Description of several new species of Holothurioidea, Jour. Acad.
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Verzeichniss der Holothurien des Kieler Mus. Bericht. Oberh.

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. V.

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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,
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1850 Anatomische Studien ueber die Echinodermen. Miillers Arch,
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1854 Ueber den Bau der Echinodermen. Abh. Berl. Akad. Wiss. aus
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1896 Zur Kenntniss der Subfamilie der Synallactinee. Festschrift
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1851 On the Holothuridse of the Atlantic Coast of the United States.
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Eathbun R.

1879 List of the Brazilian Eehinoderms, etc. Trans. Connect. Acad.
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Selenka E.

1867 Beitrage zur Anatomie u. Systematik d. Holothurien, Zeit. Wiss.
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1868 Reisen im Archipel der Philippinen. Theil II. Wiss. Res. Bd. 1,
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Westindien von W. Kukenthal u. R. Hartmeyer. Zool. Jahrb. f.
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Stimpson W.

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1886b Report on the Holothurioidea. Bull. Mus. Comp. Zool. Vol.
XIII, pp. 1-21, pi. 1. Cambridge, Mass.
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1868 Notice of the corals and eehinoderms collected by Prof. C. F.
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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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Bull., 27, pp. 127-139.

1921. Studies in the biology of freshwater mussels. Biol. Bull., 40,

pp. 210-241.
Baker, P. C— 1922. The molluscan fauna of the Big Vermillion River, 111.

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Briick, A. — 1914. Die Muskulatur von Anodonta cellensis Schrot. Zeitschr.

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569.
Gutheil, F. — 1912. Uber den Darmcanal und die Mittledarmdriise von Ano-
donta cellensis Schrot. Zeitschr. wiss. Zool., Bd. 99, S. 445-537.
Guyer, M. F. — 1922. Animal Micrology.
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mutabilis Cless. S. 39.
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Zeit. wiss. Zool., Bd. 308, S. 1.
Howes, G. B. — 1885. An atlas of practical elementary biology, p. 61.

1902. Atlas of practical elementary zootomy. PL 20-22.
Howard, A. D. — 1922. Experiments in the culture of fresh-water mussels.

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16 IOWA STUDIES IN NATURAL HISTORY

Huxley, T. H., and Martin, H. N. Revised by Howes, G. B., and Scott, D. H.

— 1892. A course of elementary instruction in practical biology. The

freshwater mussel (Anodonta cygncea) p. 20.
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of lamellibranchiate mollusks. Bull. Bur. Fish., 10, p. 389.
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Lee, A. B.— 1905. The microtomist 7s vade-mecum.

McMurrich, J. P. — 1894. Textbook of invertebrate morphology, p. 326.
Kelson, T. C. — 1918. On the origin, nature, and function of the crystalline

style of lamellibranchs. Jour. Morph., Vol. 31, pp. 53-111. Has an

exhaustive bibliography on the crystalline style.
Ortmann, A. E. — 1912. Notes on the families and genera of the Na jades.

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680.
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Zool., Bd. 125, S. 249.
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von Anodonta cellensis Schrot. Zeitsehr. wiss. Zool., Bd. 103, S. 363.
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Untersuchungen (Stockholm). Neue Folge IV, Tafel IV-VI, S. 11.
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Zeitsehr. wiss. Zool., Bd. 107, S. 1.
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geography of the Lake Okoboji region. Bull. Lab. Nat. Hist., S. U. I.,

Vol. 7, No. 2, p. 75 and p. 80.
Siebert, W. — 1913. Das Korperepithel von Anodonta cellensis. Zeitsehr. wiss.

Zool., Bel. 106, S. 449.
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Proc. U. S. Nat. Mus., Vol. 22, pp. 501-1044.
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cellensis Schrot. Zeitsehr. wiss. Zool., Bd. 104, S. 388-466.
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tomic Blattkiemer — Anodonta anatina. Bd. 1, S. 735.
Walker, B. — 1918. A synopsis of the classification of the fresh-water mollusca

of North America, north of Mexico. U. of Mich. Mus. of Zool. Misc.

Pub., No. 6.
Ward, H. B., and Whipple, G. C. — 1918. Freshwater biology.
Weisensee, H. — 1914. Die Geschlechtsverhaltnisse und der Geschlechtsapparat

bei Anodonta. Zeitsehr. wriss. Zool., Bd. 115, S. 262.
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Anodonta cellensis. Zeitsehr. wiss. Zool., Bd. 112, S. 433-522.

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.

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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.

BIBLIOGKAPHY

1. Atkinson, G. F. Contribution to the biology of the organism causing

leguminous tubercles. Bot. Gaz. 18; 157-166. 1893.

2. Demeter, H. ttber "Plasmoptysen-Mykorrhiza.,, Flora 116; 405-456.

1923.

3. Frank, B. Ueber die auf Wurzelsymbiose beruhende Ernahrung gewisser

Baume durch unter-irdische Pilze. Ber. d. deutsch. Bot. Ges. 3: 128-
145. 1885.

4. Gallaud, J. etudes sur les mycorhizes endotrophes. Rev. gen. de Bot.

17: 5-48; 66-85; 123-136; 223-239; 313-325; 423-433; 479-500. 1905.

5. Goddard, H. N. Can fungi living in agricultural soil assimilate free

nitrogen? Bot. Gaz. 56: 249-304. 1913.

6. Jones, F. R. A mycorrhizal fungus in the roots of legumes and some

other plants. Jour. Agr. Res. 29: 459-470. 1924.

7. Knudson, L. Physiological study of the symbiotic germination of orchid

seeds. Bot. Gaz. 79: 345-379. 1925.

8. Magrou, J. Symbiosis and tuberization. Ann. Sci. Nat. Bot. 10 Ser.,

3: 181-275. 1921.

9. Melin, E. On the mycorrhizas of Pinus silvestris and Picea dbies. Jour.

Ecol. 9: 254-257. 1921.

10. Experimentelle Untersuchungen fiber die Konstitution und

Oekologie der Mycorrhizen von Pinus silvestris und Picea abies. Mykol.
Untersuch und Ber. 2: 73-330. 1923. Abst. from Rev. of Appl. Myc.
3: 540-541. 1924.

11. Experimentelle Untersuchungen fiber die Birkenund und Espen-

mycorrhizen und ihre Pilzsymbionten. Svensk. Bot. Tidskr. 4: 479-
520. 1923. Abst. from Rev. of Appl. Myc. 3: 358-359. 1924.

12. Uber den Einfluss der Wasserstoffionkonzentrationen auf die

Virulenz der Wurzelpilze von Kiefer und Fichte. Bot. Notiser. 1:
38-48. 1924. Abst. from Rev. of Appl. Myc. 3: 470. 1924.

13# and Helleberg, K. "ttber die Aktivitat von proteolytischen und

verwandten Enzymen einiger als Mycorrhizenpilze bekannten Hymeno-
myceten. Biochem. Zeitschr. 157: 146-155. 1925.

14. Miehe, H. Anatomische Untersuchungen der Pilzsymbiose bei Casuarine

equisetifolia nebst einigen Bermerkungen fiber das Mykorhizen pro-
blem. Flora: 111-112: 431-449. 1918.

15. Molisch, H. Pflanzenphysiologie. 1917.

16. Paulson, R. Tree Mycorrhiza. Trans. Brit. Myc. Soc. 9: 213-217. 1924.

17. Peyronel, B. Fructification de Pendophyte a arbuscules et a vesicules

des mycorrhizes endotrophes. Bull. Soc. Myc. de France 39: 119-126.
1923.

18. Rayner, M. C. Obligate symbiosis in Calluna vulgaris. Ann. Bot. 29:

97-135. 1915.

57

58 IOWA STUDIES IN NATURAL HISTORY

19# The nutrition of mycorrhiza plants; Calluna vulgaris. Brit.

Jour. Exp. Biol. 2: 265-293. 1925. Abst. from Rev. Appl. Myc. 4:
428-430. 1925.

20. An endotrophie fungus in the Coniferae. Nature 115: 14-15,

1925.

21. Mycorrhiza. New Phytol. 25: 1-50. 1926. (To be continued).

22. Skene, M. The Biology of Flowering Plants. London, 1924.

23. Thomas, M. B. The genus Corallorrhisa. Bot. Gaz. 18: 166-170. 1893.

24. West, C. On Stigeosporium marattiacearum and the mycorrhiza of the

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.

35

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