The mollusca of Muscatine County and vicinity

r~T

BIOLOGY
LIBRARY

-"

THE MOLLUSCA

OP

IUSCATINE COUNTY AND VICINITY.

BY

THE MUSCATINE CONCHOLOGICAL CLUB,

MUSCATINE, IOWA.

F. M. WITTER, PRESIDENT.

BOSTON :
S. E. GASSING AND COMPANY.

1883.

THE MOLLTJSCA

OF

MUSCATINE COUNTY AND VICINITY.

BY

THE MUSCATINE CONCHOLOGICAL CLUB,

\\

MUSCATINE, IOWA.

F. M. WITTER, PRESIDENT.

BOSTON :
S. E. CASSINO AND COMPANY.

1883.

BIOLOGr
LIBRARY

THE &kllifi /i>lL ^AM-E&: LEWIS

OF MOHAWK, N.Y.,
THE FIRST AMOKG CONCHOLOGISTS,

AND THE

NEVER-TIRING FRIEND OF THE NOVICE IN THIS BEAUTIFUL
AND FASCINATING STUDY,

Is tfjis Etttle Folutne

MOST GRATEFULLY DEDICATED.

/7T

PREFACE.

IN preparing this list of the mollusca of Muscatine County, we
have not thought it desirable to attempt descriptions of well-
known species. Where some marked variation or some peculiar-
ity has appeared, that seemed to us likely to be of interest to
conchologists, and that would serve as guides to those students
and collectors who come after us, we have put it on record. The
size, and in some instances the weight, we have given, since it is
certain that the conditions under which the mollusk lives exert
a marked influence upon these, as well as the form and color.

All the forms catalogued by us are in the cabinet of the presi-
dent, F. M. Witter ; and he has collected all the shells given in
our list. We therefore feel certain that no stray shells have crept
in from our exchanges.

Much might have been said concerning many species of our
Unionidce, but we found it necessary to write somewhat according
to our purse. We do not see why the length of a shell should
always be less than its breadth. In giving the measurements
in the families Unionidce and Oorbiculadce, we use the terms
"length," "breadth," and "diameter" as follows: when the
shell is placed in the position it occupies when travelling, the
greatest horizontal space it fills we call its length, and the greatest
space filled at right angles to this, and vertical, we call its
breadth; and, when the shell is placed on its side, the greatest
height in this position we call its diameter. We regard the shell as
having three axes, all at right angles to each other : therefore, in
any shell that is a sphere, these will be equal. All measurements
of shells are from examples found in this county or vicinity, unless
otherwise specified. We have measured the largest, and, where
a great difference existed in the size of the mature shell, we have
also given the smallest. We have followed an alphabetical order
in the family Unionidce.

M94026

4 PREFACE.

As this may fall into the hands of conchologists, we would like
to ask a few questions, especially in relation to the interesting
family Unionidce.

What is known about the sex ? We are led to believe they are
hermaphrodite, with neutrals.

How do the muscular impressions change as the mollusk grows ?
For example : in a young A. grandis the anterior and posterior
adductors may be less than an inch apart ; eventually they are
more than six inches apart. How does this occur ?

Does the form of a shell alter with age ?

Is there a period of maturity ? How long do they live ? What
is the nature of their food ?

These questions may all have been fully explained ; but we have
seen nothing satisfactory.

In the study of our rnollusca, we have used the following works
in the library of F. M. Witter, and numerous exchanges of shells
from various parts of the United States. Lea's Naiades, from
" Philadelphia Transcript ; " " Observations on the Genus Unio,"
the last six volumes, and " Synopsis of the Family Unionidse," of
1870; "American Conchologist," seven volumes; "Monograph
of the Unionidse," by Conrad; "Monograph of the Terrestrial
Mollusca of the United States," by George W. Tryon, jun. ;
" Mollusca of New York," by James E. DeKay ; "Land and
Fresh- Water Shells of North America," Parts I., II., III., and
IV., Smithsonian publication; "American Conchology," Say;
" Recent and Fossil Shells," Woodward ; " Treatise on Shells and
Shell-Fish," by Swainson ; " Conchologia Cestrica," Hartman &
Michener ; " Turton's British Shells," by J. E. Gray ; " Land and
Fresh- Water Shells of La Salle County, 111.," by W. W. Calkins ;
and various local lists and reports in government surveys.

We desire to express our thanks to Dr. R. M. Byrnes of Cin-
cinnati, O. ; Dr. James Lewis of Mohawk, N. Y. ; Professor George
W. Tryon, jun., Philadelphia; Professor John W. Taylor, Leeds,
Eng. ; and man}^ other gentlemen with whom we have corre-
sponded, and exchanged specimens. The following is a list of
those who have been or are now connected with our club : F. M.
Witter and daughter Anna, George Moore, Albert Knoblauch, James
Stockdale, William L. Roach, Charles Braunwarth, Fred. Green,
John Fogarty, John Dobbs, Isaac Mathewson, Emanuel Daniels.

THE MOLLUSCA

OP

MUSCATINE COUNTY AND VICINITY,

HELICID^l.

HELIX.

H. arborea, SAY. — Abundant wherever any protection from the

sun is afforded. Seems to be somewhat gregarious ; 20 to 30

sometimes found together in hibernation. Greatest diam.,

6.6 ; least, 5.6 ; height, 3 mm.
H. viridula, MENKE. — Very rare. Found with arborea,- from

which it is difficult to clearly distinguish it. Greatest diam.,

5 ; least, 4.3 ; height, 2 mm.
H. minuscula, BINNEY. — Somewhat rare. In all damp woods, in

mould about logs and stumps. Greatest diam., 1.8; least,

1.6 ; height, .8 mm.
H. fulva, DRAPARNAUD. — Rare. Wide-spread in damp woods.

Shell fragile. Greatest diam., 2.4 ; least, 2 ; height, 1.4 mm.
H. lineata, SAY. — Rare. Widely distributed ; damp woods and

deep ravines. Greatest diam., 3.8; least, 3.6; height, 1.4

mm.
H. eoncava, SAY. — Rather rare. Wyoming Hills ; Cedar River

bottom ; railroad one mile north of Muscatine ; one mile

above Drury's Landing, along foot of bluff, in Illinois.

Greatest diam., 16 ; least, 13 ; height, 6.5 mm.
H. alternata, SAY. — Common. In loam in woods. Greatest

diam., 21 ; least, 18 ; height, 10 mm.
H. perspectiva, SAY. — Very rare. Only two specimens have been

5

6 " * ' TH^E WO-LLUSCA OF MUSCATINE COUNTY.

" • ^epWted? frpjp t*UKS. pegion, and these were found on Geneva

Island by F. Kaufmann, jun. Greatest diara., 9; least, 8;
height, 3.4 mm.

H. striatella, ANTHONY. — Quite rare. Railroad one mile north of
Muscatine ; in sandy loam. Greatest diam., 5.6; least, 5;
height, 2 mm.

H, labyrinthica, SAY. — Rare. In nearly all of our groves ; some-
what more common near Des Moines, lo. Greatest diam.,
2.6 ; least, 2.4 ; height, 1.6 mm.

H. hirsuta, SAY. — Common. Along railroad north of Muscatine ;
foot of bluff above Drury's Landing; Des Moines, lo. ;
collects in considerable numbers in hibernation. Greatest
diam., 9 ; least, 8 ; height, 4.6 mm.

H, monodon, RACKETT. — Very rare. Dead shells found occasion-
ally. Not so rare near Des Moines. Greatest diam., 10.75 ;
least, 9.1 ; height, 5.6 mm.

Var. leaii, WARD. — Abundant along railroad north of Mus-
catine ; found along foot of bluff above Drury's Landing. It
seems to hibernate in holes made by burrowing animals.
Greatest diam., 8.4 ; least, 7.4 ; height, 4.6 mm.

H. albolabris, SAY. — Very rare near Muscatine, not more than
four live shells having been found in the past three }'ears ;
very abundant near Des Moines, along with clausa, profunda,
and alternata. The Iowa albolabris is a more delicate shell,
and nearer white than the same species from Ohio and east-
ward. It is often of a pink shade. Greatest diam., 27;
least, 24 ; height, 15.2 mm.

H. multilineata, SAY. — Very abundant on Geneva and adjacent
islands, two miles east of Muscatine ; rare at Gooseberry
Point, nearly opposite the city of Muscatine ; but those found
at this place are nearty all without bands (alba) , or the bands
are so crowded as to render it difficult to separate them, giv-
ing the shell a strong tinge of red (rubra) . One specimen of
the variety alba measures as follows: greatest diam., 26;
least, 23 ; height, 19.4 mm., being unusually high. A banded
example from Geneva : greatest diam., 30 ; least, 25 ; height,
15.6 mm. And a banded specimen found near this city
measures as follows: greatest diam., 17.8; least, 15.6;
height, 12 mm.

THE MOLL USC A OF MUSCATTNE COUNTY. 7

H. thyroides, SAY. — Very rare in Muscatine County or in Iowa,
so far as we know. Judging from dead shells, it was quite
abundant, not long ago, at Wyoming Hills, eight miles east
of Muscatine. Live shells are very rare there now, it being
the only place where the species is found in Iowa in this
region. Common two miles above Drury's Landing, along
foot of sandstone bluffs. Greatest diam., 26.6 ; least, 22.2 ;
height, 15 mm.

H. clausa, SAY. — Very rare in this region. Both dead and live
shells have been found in nearly all our deep ravines. Very
abundant three miles north of DCS Moines, along with albola-
bris, prof undo, , and alter nata. The largest and smallest
mature specimens found here measure as follows : greatest
diam., 19.4, 15.6; least, 15.4, 13; height, 12.2, 9.8 mm.,
respectively.

H. profunda, SAY. — Has not been found in this vicinity in Iowa.
Occurs at Gooseberry Point, two miles above Drury's Land-
ing, and near Des Moines. At all of these places it is rare.
A white variety is common among the specimens found.
White variety, greatest diam., 29.4; least, 25; height, 14
mm. Banded variety, greatest diam., 29.4; least, 24.8;
height, 15 mm.

H. pulchella, MULL. — Common, in Mr. J. Stockdale's yard in
Muscatine, the only place where we have found it alive. It
is common in the loess of this city, and we have live speci-
mens of the variety costata from Davenport. Those from the
loess are somewhat costate, live shells from Mr. Stockdale's
3~ard are the true pulchella, and those from Davenport are
conspicuously costate. They differ greatly in size. Loess,
greatest diam., 3 mm. ; Stockdale's, 2.4 mm. ; Davenport,
2 mm.

LIMAX.

L. campestris, BINNEY. — Abundant about gardens.

CIONELLA.

C. subcylindrica, LINN. — Rare. One mile north of Muscatine on
Chicago, Rock Island, and Pacific Railroad embankment ;
under vines in sandy loam. Has not been found elsewhere in
this county, and has not been reported from any other part of

8 THE MOLLUSCA OF MUSCATINE COUNTY.

the State. It was common, or almost abundant, at the place
mentioned above, some three years ago. Length, 5.6 mm.

PUPA.

P. pentodon, SAY. — Rare. About old logs and leaves where it is
damp.

P. fallax, SAY. — Ven7 rare. Appears to be confined to a space
scarcely more than ten feet square in a woodland about one
mile above Muscatine.

P. armifera, SAY. — Widely dispersed. Prefers loam among grass-
roots about stumps and logs in woods. Common.

P. contracta, SAY. — Common. Found with armifera.

SUCCINEA.
S. ovalis, GOULD. — Very abundant in swamps. Associated with

Limnece. Shell very thin.
S. avara, SAY. — Rare. Two forms are found here, — one, extreme

length, — mm., and seems to live in the ground ; the other,

— mm. long, and has about the snme habit as S. obliqua.
S. obliqua, SAY. — Abundant on Geneva Island with H. multiline-

ata. Shell much stronger than ovalis. They do not seem to

be hermaphrodite.

PHYLOMYCIDJE.

TEBENNOPHORUS.

T. carolinensis, Bosc. — Common. In woods about old deca}-ing
stumps and logs. Easily found on warm, damp days. The
same may be said of all our land-mollusks.

AUBICULIDJS.

CARYCHIUM.

C. exigumn, SAY. — Common. This minute mollusk is wide-spread ;
is found under damp, decaj^ing leaves in woods.

LIMNEID^S.

LIMNEA.

L. reflexa, SAY. — Abundant in nearly all of our ponds ; and there
are almost as many different forms as ponds. Near West

THE MOLLUSCA OF MUSCATINE COUNTY. 9

Liberty, in Muscatine County, is a form which approaches very
near to the typical reflexa of Say. Average measurements of
some of the different forms are as follows : —

Length. Greatest Diameter. . Length of Aperture,

mm. mm. mm.

37 12 18

37 13 17

37 12 15

32 9 13

27 10 13

One variety is slender, wrinkled, and very light color, whilst
most of the others are dark, rather tumid, and scarcel}7 wrin-
kled. Variety zebra (Tryon) has in some specimens well-
marked, alternating dark and light lines or bands parallel to
the margin of the outer lip ; but it shades off into varieties
without light lines. The short form was very abundant two
years ago in Brigg's Slash, on Muscatine Island. TLe epider-
mis was either eaten or eroded from the spire of nearly all of
this variety.

L, desidiosa, SAY. — Abundant along muddy margins of ponds.
Light horn color ; slight umbilical opening. Length of shell,
14 ; of aperture, 8 mm.

L. pallida, ADAMS. — Was very abundant about three years ago
in a small pond in Muscatine, but seems now to be extinct in
this region. Length of shell, 11.5 ; of aperture, 6.5 mm.
Epidermis is dark, or black ; but this may be some substance
foreign to the shell. Shell bluish white in the aperture. It
is probable that L. humilis (Say) is found here, inasmuch as
it is reported by Mr. W. A. Marsh, from Aledo, 111., only
eighteen miles from Muscatine ; and we have small Limnece
that do not seem to fall under desidiosa or pallida.

PHYSA.

P, gyrina, SAY. — It is very difficult to say whether this species is
abundant or not, or whether it really exists here. We have
plenty of Physce; but just what they all are, it seems nobod}7"
knows. As far west as Des Moines, the relative length of
aperture and shell accords better with Say's description of
the species than shells found here. The largest Physa that I

10 THE MOLLUSC A OF MUSCATINE COUNTY.

have seen from this State is 24 mm. long ; aperture, 16 mm. ;
and greatest width, 14 mm. Whirls, about C ; spire very
acute. This form has been called heterostropha (Say) by
many of our correspondents.

P. heterostropha, SAY. — Abundant. Length of shell, 19; of
aperture, 15 ; diam. of shell, 12 mm. Whirls, 5 ; first very
large ; epidermis very light horn color.

P. ampullacea, GOULD. — This may be a form of heterostropha;
but it has been called ampullacea^ and it corresponds to the
figure and description in Part II., "Land and Fresh- Water
Shells" (W. G. Binney). Length of shell, 19 ; of aperture,
13; diam., 10 mm. Whirls, 5, reddish horn color; shell
firm.

P. virgata, GOULD. — I discovered this beautiful little Physa in a
pond in South Muscatine, in the spring of 1877, along with
ampullacea and heterostropha. The pond became dry the
following year ; and it has not been found elsewhere in this
vicinity. Length of shell, 10 ; of aperture, 7.5 mm.

PLANORBIS.

P. trivolvis, SAY. — Common. This species is protean.
P. bicarinatus, SAY. — Common. Diam., 12 mm.
P. exacutus, SAY. — Common. Diam., 6.6 mm.
P. deflectus, SAY. — Somewhat rare. Might be mistaken for albus.

Diam., 6 mm.

P. albus, MUL. — Common. Diam., 6 mm.
P. parvus, SAY. — Common. Diam., 4 mm.

SEGMENTINA.

S, armigera, SAY. — Hardly common. We have called this species
wheatleyi heretofore; but, on careful examination, it seems
to be armigera. Diam., 7 mm.

ANCYLUS.

A, diaphanus, HALDEMAN. — Somewhat rare. This species was
identified for us as fuscus; but, on studying the figures and
description in "Land and Fresh-Water Shells," Part II. (W.
G. Binney), I am satisfied our Ancylus must be diaphanus,

THE MOLLUSCA OF MUSCAT INE COUNTY. 11

unless fuscus is extremely variable. Shell almost transparent ;
apex obtuse. Length, 7 ; breadth, 4.2; height, 2 mm. We
have a long, dark form, which answers closely to the descrip-
tion of parallelus (Haldeman). Length, 8.6 ; breadth, 4.8;
height, 2.5 mm. Many of our dark forms are probably dia-
phanus, covered more or less with some foreign substance.
So far, they have been found in stagnant water only, and I
believe entirely in Muscatine Slough and Keokuk Lake.

VALVATIDjE.

VALVATA.

V. tricarinata, SAY. — Abundant in nearly all of our ponds. Two
forms, easily distinguished, abound here. We have not yet
found both forms in the same pond. But for this we should
be disposed to regard one as a prolific, and the other a sterile
form. One form is flat, with apex of spire a little below
a level with the last whirl ; umbilicus large and shallow :
greatest diam., 5.6 mm. The other has an elevated spire, a
small and deep umbilicus: greatest diam., 4.6 mm. The
latter is a much smaller shell, as is plainly shown in not
less than a hundred specimens of each form in our collection.

VIVIPARID^l.

VIVIPARA.

V. intertexta, SAY. — Abundant in most ponds, and especially in
Muscatine Slough and Keokuk Lake. Some shells show light
bands parallel with the sutures. Length, 28 mm.

V. contectoides, W. G. BINNEY. — We have one "dead" shell of
this species found on the bank of the Cedar River, at Moscow,
in Muscatine Count}-. The shell is in good condition, and
plainly indicates the existence of the species near where it
was found. Length, 27.5 mm.

MELANTHO.

M. subsolida, ANTHONY. — Very common. We have the form de-
scribed by Anthony. A specimen in my collection has 7^

12 THE MOLLUSC A OF MUSCATINE COUNTY.

whirls ; is perfect to the apex. Length of shell, 51 ; of aper-
ture, 23 mm.

M. decisa, SAY. — Abundant. I doubt very much if any well-
marked difference exists between this and the preceding.
Length of shell, 34 ; of aperture, 18 mm. A reversed " dead "
shell, probably a decisa, was found at Moscow in this county.
We have examples of this genus from Alabama, New York,
Ohio, Michigan, Illinois, and Iowa : they are called ponderosa,
obesa, Integra, decisa, subsolida, rufa, etc. In the whole
range there seems to be no more difference or variation than
exists in our H. multilineata. The larger and heavier shells
are in our streams ; the lighter, in our ponds.

LIOPLAX.

L. subcarinata, SAY. — Common. In ponds. Most specimens
show a carina near the apex. Length of shell, 16 ; of aper-
ture, 8 mm.

BSSOi

BYTHINELLA.
B. obtusa, LEA. — Rare. In ponds. Length, 4.2 mm.

SOMATOGYRUS.

S. isogonus, SAY. — Common. In ponds and slow-running streams.
Length of shell, 8.2 ; of aperture, 5.8 mm.

AMNICOLA.
A, cincinnatiensis, ANTHONY. — Common. Ponds. Length, 5 mm.

POMATIOPSIS.

P. lapidaria, SAY. — Ver}^ rare. We have in our collection three
good specimens of "dead" shells, evidently of this species,
which we found among drift-wood on the bank of the Missis-
sippi, about two miles above Muscatine. They could hardly
have come from the loess, a mile or two farther up, since we
have not yet found them in this deposit anywhere in this
region ; and we have not found other shells of the loess along
the river in this way. Length of shell, G.8 ; of aperture,
2.2 mm.

THE MOLLUSC A OF MUSCATINE COUNTY. 13

r

STREPOMATID^J.

PLEUROCERA.

Pleurocera subulare, LEA. — Was very abundant at the mouth of
Burdett's Slough three }'ears ago, but we have hardly found it
since. "Dead" shells abound along the Cedar. Length of
shell, 23 ; of aperture, 7 ; diam., 7 mm.

GONIOBASIS.

G. cubicoides, ANTHONY. — A few " dead " shells have been found
on Cedar River. Length of shell, 16.6; of aperture, 7;
diam., 8.5 mm.

UNIONID^.

UNIO.

IT. sesopus, GREEN. — Common. Mississippi; at Muscatine. Thick
near umbones; heavy; epidermis in young shells light yellow,
dark in old individuals. Length, 8.5; breadth, 6; diam.,
4.5 cm.

U. alatus, SAY. — Common in Mississippi. Old shells apparent!}7
nons}Tmphanote ; nacre purple. Length, 15 ; breadth, 9 ;
diam., 5 cm.

U. anodontoides, LEA. — Abundant in Mississippi ; found also in
the Cedar. There seem to be two forms of this fine shell.
Form a seems to prefer sand ; epidermis pale yellow ; no rays ;
umbones plain ; is much larger than b: length, 12.8 ; breadth,
6.5 ; diam., 5.6 cm. Form b prefers muddy sloughs, is beau-
tifully rayed with green, and umbones are undulated : length,
8 ; breadth, 3.5 ; diam., 3.2 cm.

U. asperrimus, LEA. — Somewhat rare. Mississippi River. Two
forms abound here. One agrees with figure and description in
Lea's "Observations on the Genus Unio," except the shell
is much narrower posteriorly, the umbones are considerably
more elevated, and somewhat more anterior, than in the figure,
Plate V., vol. iv. : length, 10.2 ; breadth, 7.2 ; diam., 5.3 cm.
The other is the same as the example figured and described in
Say's "American Conchology : " length, 8.7; breadth, 7.3;
diam., 5.3 cm. It ma}' be, the long thin form is sterile, and
the other is prolific.

14 THE MOLLUSC A OF MUSCATINE COUNTY.

TJ. arctior, LEA. — Very rare. Among the gibbosus (Barnes)
found here is occasional!}' a shell much smaller than the
largest gibbosus, nacre bluish white, convex on basal edge, and
showing rays more or less distinctly. It is, no doubt, a variety
of gibbosus, since the color of the nacre, and form of basal
margin, are both variable in gibbosus.

TJ. capax, GREEN. — Rare. Mississippi. Length, 10.8; breadth,
7.7 ; diain., 6.8 cm.

U. coccineus, LEA. — Cedar, Iowa, and Des Moines. Some speci-
mens from Iowa City are conspicuously rayed with green.
Rather common in the Iowa and Des Moines. Length, 7 ;
breadth, 5.5 ; diam., 4 cm.

U. cornutus, BARNES. — Common. Mississippi. Epidermis in some
examples is closely rayed, with interrupted or zigzag green
lines, giving the shell a beautiful appearance. This shades
into a light 3*eliow, destitute of ra}~s. One row of increasing
tubercles about central in eacli valve : the largest shells have
four to five in each row. Length, 5.5 ; breadth, 4.6 ; diam.,
4.3 cm.

U. crassidens, LAM. — Rare. Mississippi. This species seems to
be very nearty related to ligamentmus (Lam.) and gibbosus
(Barnes) . It is niger of Raf. A more or less purple nacre, and
black epidermis. Length, 14; breadth, 8.1 ; diam., 6.4 cm.

U. donaciformis, LEA. — If this and zigzag (Lea) are two good
species, we are unable to sa}r whether it is rare or common.
Habitat Mississippi, on sandy bottoms. Lea figured and de-
scribed this form in 1827, and zigzag in 1829. We can see no
difference in our shells, except some are shorter and more
tumid than others, and the epidermis varies from green to
yellow. Length, 3.4; breadth, 2.2; diam., 1.8 cm.

U. dorfeuilliaims, LEA. — It is with some hesitation that we put
this species in our list. We are unable to separate it from
among the shells found in the Mississippi near us, which we
regard pustalosus. If Lea's figures and descriptions are cor-
rect, we have no shell that quite corresponds to them ; but
we can place two examples we have from the Cedar, in this
county, nowhere else. Shell very thick and heavy, almost
without pustules ; umbones and ligament very prominent.
Length, 8.3 ; breadth, 7.5 ; diam., 5.6 cm.

THE MOLL USC A OF MUKCATINE COUNTY. 15

IT. ebenus, LEA. — Common. Mississippi River. We have shells
of this species of all ages ; and none of them seem to be
marked with yellow behind the beaks, as figured and described
by Lea. Length, 8.8 ; breadth, 7.5 ; diam., 5.4 cm.

IT. elegans, LEA. — Rather rare. Mississippi and Cedar. Epider-
mis usually rayed with green, but some are destitute of rays,
having a light-yellow color ; nacre generally white, but some-
times pink. The latter is very handsome when polished.
The largest shells occur in Cedar. Length, 6.7 ; breadth,
5.5 ; diam., 3.7 cm.

IT. ellipsis, LEA. — Common. Mississippi and Cedar. Beaks much
more anterior in some examples than in others ; generally
distinctly raj*ed. Largest shell, so far, is from the Cedar.
Length, 8.6 ; breadth, 6.2 ; diam., 5.2 cm.

U, gibbosus (dilatatus, RAF.), BARNES. — Mississippi. Common.
(See arctior.) Length, 10.5 ; breadth, 5.2 ; diam., 3.3 cm.

IT. gracilis, BARNES. — Common. Mississippi and Cedar. Seems
to prefer very muddy bottoms. Resembles Icevissimus (Lea) ,
but epidermis is less polished ; generally rayed with green ;
posterior wing much less elevated, and no anterior wing ;
nacre white, with a tendency to purple back of the umbonal
cavity; shell very thin, and liable to crack when dry.
Largest shells from the Cedar. Length, 16.5; breadth,
10.5 ; diam., 5.2 cm.

U. graniferus, LEA. — Rare. Mississippi. This is most likely ver-
rucosus of Barnes, and should be so called ; is a most beautiful
shell when polished (the same process as for marble). Nacre
purple. Length, 8.5; breadth, 7.2; diam., 5.4 cm.

U. laevissimus, LEA. — Common. Mississippi and Cedar. Epi-
dermis more or less purple, and highly polished ; nacre
purple ; substance of shell very thin. Very young shells
are almost transparent ; and we have found them attached
to objects by byssal threads. Largest shell from Cedar.
Length, 17 ; breadth without wing, 10.5 ; diam., 4.2 cm.

U. ligamentinus, LAM. — Common. Mississippi. Epidermis in
3Toung specimens green when the nacre is white ; or, when red
is prominent, the nacre is pink. Length, 11.3 ; breadth, 7.1 ;
diam., 5.2 cm.

U, luteolus, LAM. — Common in slough below Keokuk Lake.

16 THE MOLLUSC A OF MUSCATINE COUNTY.

Found also in Mississippi, creek at Brown's Ferry on Cedar,
Mud Creek at Wilton, Des Moines River at Des Moines,
Skunk River at Ames : in fact, it is our most widely dis-
persed species. No little confusion exists concerning this
species. There are at least two well-marked forms here, and
I am inclined to say three. If we limit the species to those
having numerous fine undulating lines on the beaks, we shall
include siliquoideus (Barnes) and luteolus (Lam.), and exclude
a form with but two or three coarse folds about the beaks,
which we believe may be called ventricosus (Barnes) ; but the
figure of this species in American conchology is nearer to our
occidens (Lea). Siliquoideus has been abandoned by Lea.
This would leave the first group to luteolus. Of the long,
narrow, and generally thin examples, with numerous undula-
tions about the beaks, those from creek near Brown's Feriy,
Skunk, and Des Moines, are much smaller in every wa}r,
umbones very low, and epidermis with few and small green
rays over the light-yellow ground. The largest of this group
measures as follows: length, 7.8; breadth, 4.4; diam., 2.2
cm. Those from Muscatine Slough and Mud Creek are much
larger ; umbones very prominent ; green ra}*s generally nu-
merous and broad ; old specimens nearly black. Some ex-
amples are very beautiful. Length, 11.3 ; breadth, 6 ; diam.,
4.5 cm. In both groups there are thin forms, narrow and
rounded, or somewhat pointed posteriorly ; and short, tumid
forms, wider, and truncated posteriori}'. An example of the
latter form measures, length, 9.6; breadth, 5.8; diam., 6.2
cm. These are, no doubt, sterile and fertile forms.

U. metanevms, RAF. — Common. Mississippi and Cedar. We
have a rare form, with few or no tubercles, and with a very
prominent lobe, gradually increasing in width from the um-
bones to the posterior basal margin. Length, 6.7; breadth,
5.5 ; diam., 4.5 cm.

U. monodontus, SAY. — Mississippi, near mouth of Geneva Creek,
and on sand-bar opposite Mr. B. -Hershey's mill, we have
found a few " dead " shells. Those at the latter place were
nearly fresh. No live shells have been secured, so far as we
know, nearer than Davenport. Length, 12.5; breadth, 4.8;
diam., 3 cm.

THE MOLLUSC A OF MUSCATINE COUNTY. 17

IT. nmltiplicatus, LEA (heros, SAY). — Very rare. Mississippi, at
Muscatine, and lake near Port Louisa. Length, 16 ; breadth,
11.2; diam., 7.2 cm. A "dead" shell found near Port
Louisa measures, length, 17.5 ; breadth, 12.5 cm. ; and
weighs 1.5 Ibs.

IT. mississippiensis, CONRAD. — Abundant in Muscatine Slough,
above Keokuk Lake. It abounds in nearlj* all ponds near the
Mississippi and Cedar. The sterile form seems to be much
larger than the prolific, attenuated and pointed posterior^;
while the latter is less flattened, and is conspicuously trun-
cated at the posterior extremity. Measurements of largest
sterile form are, length, 10.7; breadth, 4.5 ; diam., 3.4 cm.

IT. obliquus, LAM. — We have one valve from the Mississippi at
Muscatine, of what corresponds to shells called by this name,
from the Ohio. The shell is deformed, and may not be obli-
quus. Obliquus, as .figured and described in " Monograph of
the Unionidae," by Conrad, is ebenus of Lea.

U. occidens, LEA. — Very common. Mississippi and Cedar. Young
shells are beautiful. It varies in form, and in color of epider-
mis and nacre. It is often difficult to distinguish it from
ventricosus (Barnes). The difference cannot be due to the
sexes, inasmuch as thin, long forms, and tumid, abrupt, or
truncated forms, are found in both groups. Ventricosus is
generally abundant in the interior streams of this State, and
varies towards luteolus, whilst occidens abounds in the Mis-
sissippi, and runs into ventricosus. No doubt, ovatus (Say)
and subovatus (Lea) are included in this range of variation.
We have a specimen from the Cedar that answers to the
figure and description of subovatus in Lea's " Observations,"
except that the umbones are not quite so far forward in our
shell. Ovatus (Say), figured in Conrad's "Monograph," is
most probably a form of our ventricosus (Say) , especially those
with a light-yellow epidermis, with few or no rays. It will
require considerable skill to make out the difference between
the figure of ventricosus in Say's "American Conchology,"
and of occidens in Lea's "Observations." Length, 12.5;
breadth, 8.5 ; diam., 6 cm.

II. orbiculatus, HILD. — Rare. Mississippi. Shell variable. Epi-
dermis in young shells generally yellowish brown, and more

18 THE MOLL USC A OF MUSCATINE COUNTY.

or less distinctly ra}~ed : mature specimens are generally dark
or black over the umbones, though some are decidedly yellow.
Nacre generally white, often rose and salmon. Some forms
resemble ellipsis (Lea) ; are figured and described in " Mono-
graph of the Unionidse," by Conrad, under the name of crassus
(Say) ; and in Lea's " Observations on the Genus Unio," vol.
ix., it is called higginsii (Lea). The figures and descriptions
of higginsii were made from specimens obtained at Muscatine
by Mr. Frank Higgins. Some of the shells before us are un-
doubtedly higginsii. In " American Concholog}^ " Sa}T figures
and describes another form of this species as abruptus. Out
of twenty-one examples now before us, eight are certainly
abruptus of Say. Lea places abruptus and crassus as s}~no-
nymes of orbiculatus in his u Synopsis of the Family Unioni-
dse " (1870) ; and we are constrained to add higginsii to the
same list. The difference in form is, no doubt, caused by fer-
tility or sterility, and kind and quantity of food.

U. parvus, BARNES. — Hardly common. Mississippi, Muscatine
Slough, Cedar, Mud Creek, Des Moines, etc. Length, 3.8 ;
breadth, 2 ; diam., 1.4 cm.

U, plicatus (LESUEUR?). — Abundant. Mississippi, Muscatine
Slough, Cedar. Some doubt exists as to the separation of
this species from undulatus of Barnes, or costatus of Raf.
The figure and description of costatus in Conrad's "Mono-
graph," plate VII., agrees with a form found in Mud Creek
at Wilton, and in the Des Moines at Des Moines, which we
call undulatus; and plate LIX. in same work is our plicatus.
Plicatus, as we have it, is a very heavy shell, reaching one
pound four ounces, which is more than three times the weight
of our largest and heaviest undulatus from Mud Creek. Pli-
catus is generally very tumid, has high and prominent umbones,
and the epidermis of very young shells is decidedly green.
Undulatus is much less tumid, very low umbones, and young
shells from Des Moines (the young of this species have not
been found in this count}') have a light-j'ellow epidermis.
Length, 14.5; breadth, 10.5; diam., 7.6 cm.

TJ, pustulatus, LEA. — Rare. Mississippi. Length, 7.2 ; breadth,
6 ; diam., 4.4 cm.

U. pustulosus, LEA. — Mississippi, Cedar, and Des Moines. We

THE MOLLUSC A OF MUSCATINE COUNTY. 19

have alread}- stated, under dorfeuillianus, that we cannot
find constant characters to separate the two species, if there
be two. Some say pustulosus is rare here. If so, then dor-
feuillianus is abundant. What we call pustulosus, from the
interior streams, seems to fill the figure and description of
schnolcraftensis of Lea in ''Observations." Vallatus (Lea)
is most likely found in the Des Moines, and, it may be, in
the Cedar.

U. pyramidatus, LEA. — Rare. Mississippi. Mytiloides (Raf.), as
figured and described in Conrad's " Monograph," is the same,
it appears to us, as Lea's pyramidatus. Nacre generally
white, sometimes pink. It is probable that some of our
shells catalogued as solidus (Lea) are pyramidatus of the
same author. Length, 8.5; breadth, 6.8; diam., 5.6cm.

II. rectus, LAMARCK. — Common. Mississippi, Cedar, Des Moines.
Nacre generally rose or pink, but occasionally white.
Weight, 8 oz. ; length, 14.5 ; breadth, 5.7 ; diam., 4.6 cm.

U. rubiginosus, LEA. — Rare. Cedar, Iowa, Des Moines. Nacre
light pink, or white. Length, 5.8; breadth, 4.5; diam.,
3.4 cm.

U, subovatus, LEA. — Cedar. (See occidens.) Length, 13.4;
breadth, 8.4 ; diam., 3.6 cm.

U. securis, LEA. — Common. Mississippi. Young specimens are
very beautiful. Length, 9 ; breadth, 6.8 ; diam., 4 cm.

U. solidus, LEA. — Very rare. Mississippi. (See pyramidatus.)
It appears to us that solidus is the 3'oung of pyramidatus.
Length, 4 ; breadth, 3.7 ; diam., 3 cm.

U. spatulatus, LEA. — Very rare. Mississippi. We found one
live specimen, at this place, of what appears to be spatulatus.
The species is found at Davenport and New Boston ; but, with
this single exception, no shell has been taken here, among
the thousands we have collected, that will compare in the
least with examples received from Professor Pratt of Daven-
port, and Mr. Marsh of Aledo, 111. Our shell is very heavy,
much heavier than longer shells referred to aboA'e. It is very
much the shape of a }"oung ligament inus. Length, 5.6 ;
breadth, 3.2 ; diam., 2.4 cm.

U. temiissimus, LEA. — Ver}* rare. Mississippi. Burdett's Slough.
Substance of shell extremely thin. Sexual difference seems

20 THE MOLLUSC A OF MUSCAT1NE COUNTY.

to he well marked. This is leptodon of Conrad. Length,
7.3 ; breadth, 3.7 ; diam., 1.7 cm.

U. triangularis, BARNES. — Rare. Mississippi. Prolific and ster-
ile forms quite distinct. Length, 4; breadth, 2.8; diam.,
2.5 cm.

U. trigonus, LEA. — Abundant. Mississippi. Young shells light
yellowish brown, sometimes slightly rayed with green. Old
shells dark or black, and much produced posteriorly. Length,
7.3 ; breadth, 6.3 ; diam., 5 cm.

U. tuberculatus, BARNES. — Common. Mississippi, Cedar. Largest
shells from Cedar. Weight, 15.5 oz. ; length, 15 ; breadth,
9.1 ; diam., 6 cm.

U. undulatus, BARNES. — Rare. Mud Creek at Wilton ; common
at Des Moines. (See plicatus.) Length, 12 ; breadth, 8.5 ;
diam., 5.6 cm.

U, ventricosus, BARNES. — Mississippi, Cedar, Des Moines; com-
mon in the two latter streams. (See occidens.) Old shells are
almost destitute of rays, and substance of shell thick. Weight
.of specimen from Cedar, 14 oz. ; length, 14.8 ; breadth, 10.7 ;
diam., 7.8 cm.

IT. wardii, LEA. — Very rare in Mississippi ; common in Cedar
and Des Moines. A very beautiful shell. We believe we
can show that this species and metanevrus are the same.
Where metanevrus lives constantly in sand, the shells are lighter
in color and substance, umbones and tubercles are less promi-
nent, and diameter of shell is less. We have a very fine
specimen from the Cedar. Weight, 7.5 oz. ; length, 10.5 ;
breadth, 8.4; diam., 5 cm.

U. zigzag, LEA. — Common. Mississippi. After considering Lea's
figures and descriptions of this and donaciformis, and com-
paring them from different localities, we think one must at
least be a variet}^ of the other. (See donaciformis.)

MARGARITANA.

M, complanata, BARNES. — Common. Mississippi, Mud Creek,
Des Moines. We have two forms, it may be, two species.
We submitted specimens to Dr. James Lewis, and he says,
" I think they are the same, though most persons would call
them distinct species : the variation in the shell is due to the

THE MOLLUSC A OF MUSCATINE COUNTY. 21

greater abundance of food in Mud Creek." Lea says this
species is symplrpiote. We have before us good representa-
tives of both forms, a is perfect!}' symplrynote, with a very
fine dorsal wing, making the disk somewhat triangular ; b is
entirety destitute of a wing, and consequently is not symphy-
note, and could not be called triangular ; a would not be
transformed into b by loosing its wing ; hinge-teeth are much
heavier in b. Measurements of a, length, 14.2 ; breadth,
including wing, 12.3 ; diam., 3 cm. Measurements of 6,
length, 15.3; breadth, 9.8; diam., 5.2 cm. It will be seen
that b is much more tumid than a. The form 6 is common in
Mud Creek at Wilton.

M. confragosa, SAY. — Rare. Sloughs and ponds near Missis-
sippi. Lateral teeth plainly present in some examples.
Length, 11 ; breadth, 8 ; diam., 5.4 cm.

M. deltoidea, LEA. — Mad Creek and Honey Creek, Delaware
County, Iowa. In Mad Creek, from two to four miles from
its mouth, we have found "dead" shells of this species
along with "dead" shells of A. ferussaciana (Lea). It is
alive in Honey Creek : it seems to have become extinct here
recently. Calceola (Lea) appears to be the same as deltoidea.
Length, 2.9 ; breadth, 1.7; diam., 1.1 cm.

M, marginata, SAY. — Very rare. Mississippi, Cedar, Des
Moines. We found it in Burdett's Slough. Our shells are
very light and small. A specimen from Des Moines measures,
length, 6.8; breadth, 4; diam., 2.6 cm.

M, rugosa, LEA. — Mississippi, Cedar, Des Moines. Rare. We
found it at Wyoming Hills and in Burdett's Slough. Length,
11.1 ; breadth, 6 ; diam., 3.8 cm.

ANODONTA.

A. corpulenta, COOPER. — Muscatine Slough. Rare. Substance of
shell very thin ; hinge margin straight ; ligament hid, or nearly
so, by the shell, which is more or less continuous from one
valve to the other ; umbones prominent, with three or four
• coarse folds about the beaks ; epidermis yellowish green ;
basal margin very convex. We are in doubt about this spe-
cies. Length, 7; breadth, 5.2; diam., 3.4 cm.
A. decora, LEA. — Muscatine Slough. Rather rare. We have

22 THE MOLLUSC A OF MUSCAT 1NE COUNTY.

shells that agree in every particular with Lea's figure and
description ; but they do not agree with examples called decora
from Ohio. We have heretofore regarded these the 3~oung of
grandis. Substance of shell very thin ; hinge margin straight,
and slightly winged back of umbones ; epidermis light about
beaks, gradually becoming darker, and terminating in a black
or nearly black band, about midway from beak to basal mar-
gin, parallel with lines of growth, the remainder green with
rather indistinct rays of lighter color ; tumid. This must be
the shell that Lea called decora. Length, 9.6 ; breadth, 6.1 ;
diam., 4.7 cm.

A. edentula, LEA. — Rather rare. Mississippi, Cedar, Mud
Creek, Des Moines. In the " Natural History of New
York" DeKay figures and describes a form unadilla, which
Lea, in his " Synopsis," gives as a synonyme of edentula. De-
Kay, in the same work, figures and describes edentula. The
latter maybe Say's undulata; but we can see no difference
between edentula and undulata. Edentula is an exception
among the species of the genus as to its habitat. So far, we
have found it in our rivers only ; whilst all the others are
limited to our ponds and sloughs, except, it may be, ferussa-
biana, and occasionally a specimen of grandis, which we find
in the Mississippi. Substance of the shell is much heavier
than any other of the sub-genus we have seen ; anterior hinge-
tooth quite prominent in some shells ; nacre generally salmon ;
muscular impressions very distinct ; epidermis dark brown.
Length, 8.1 ; breadth, 5 ; diam., 3 cm.

A. ferussaciana, LEA. — Mad Creek, Des Moines, Honey Creek in
Delaware County. A few "dead" shells have been found
in Mad Creek along with M. deltoidea. We have found live
shells at Des Moines ; but the finest are from Honey Creek,
where it appears to be common. We have examples from this
place and Des Moines that are apparently the same as wardi-
ana (Lea). A study of Lea's figures and descriptions of
these species, together with specimens, inclines us to believe
them the same, or, at most, that the latter is a variety of the
former. Shell from Honey Creek measures, length, 8.1 ;
breadth, 4 ; diam., 3 cm.

A. grandis, SAY. — Very abundant in Keokuk Lake, and in our

THE MOLLUSC A OF MUSCATINE COUNTY. 23

ponds and sloughs generally. We have never seen a figure or
description of grandis; neither have we received specimens of
this species from other localities. We have sent what we
call grandis to conchologists all over the country, including
England, and we have not had its specific identity doubted.
What seems a puzzle to us is the separation of grandis from
gigantea (Lea) . The figure and description of gigantea an-
swer to what we call grandis. Length, 19.7 ; breadth, 12.5 ;
diam., 9 cm.

A, imbecilis, SAY. — Abundant. In all of our ponds and sloughs.
Epidermis not so beautiful as those we have received from
Ohio. Length, 7.1 ; breadth, 3.4; diam., 2.5 cm.

A. plana, LEA. — Rare. Isett stone-quarry in this city; creek at
Cole's Ferry and at Des Moines. Judging from specimens
received in our exchanges, plana and decora are badly mixed.
We cannot place our shells elsewhere, unless plana and decora
are referred to grandis. There can be no doubt that the envi-
ronments of the mollusk influence the characters of the shell.
A fine specimen from the old Isett quarry measures as follows :
length, 16; breadth, 9 ; diam., 6.6 cm.

A. suborbiculata, SAY. — Common, or even abundant, in Keokuk
Lake, and lakes along Cedar, especially the lake on the west
bank of Cedar, a half-mile below Moscow. Substance of
shell thin ; epidermis highly polished, and light color, except
in very old individuals it is dark. A fine but rather fragile
shell. Length, 17.3 ; breadth, 13.3 ; diam., 6 cm.

CORBIOULAD^J.

SPH/ERIUM.
S. solidulum, PRIME. — Common in streams. Length, 13 ; breadth,

9 ; diam., 7 mm.

S, stamineum, CON. — Common. Length, 16 ; breadth, 13 ; diam.,

10 mm.

S. partumeium, SAY. — Common in ponds. Length, 15; breadth,

13 ; diam., 8 mm.
S. transversum, SAY. — Common in ponds. Length, 15 ; breadth,

10.5 ; diam., 7 mm.

PISIDIUM.

P. compressum, PRIME. Not very common.

24 THE MOLL USC A OF MUSGATINE COUNTY.

SHELLS FOUND IN THE LOESS IN MUSCATINE AND

VICINITY,

Helix cooperi, W. G. BINNEY. — Common. H. fulva, DKAP. —
Common. H. lineata, SAY. — Common. H. pulchella, MUL-
LER. — Common. H, striatella, ANTHONY. — Abundant. Pupa
blandi, MORSE. — Common. P. muscorum, LIN. — Common.
P. simplex, GOULD. — Common. Succinea avara, SAY. —
Abundant. S. obliqua, SAY. — Common. Helicina occulta,
SAY. — Rare. This species has been found alive and com-
mon in Hardin County, Iowa, by Dr. E. H. King of West Lib-
erty, from whom we have received specimens. Limnea. —
Common at one point near the top of the loess in this city.
No other water species has been found in this deposit, so far
as we know, in this locality. Not one of all our water-
mollusks is found in the loess, and only six of our living
land species. The two most abundant in the loess (H.
striatella and S. avara) are apparently nearly extinct here
now. The shells are all most perfectly preserved in the loess,
and with the exception of the loss of the epidermis, and con-
sequent bleached appearance, they are as complete as the
shells we find in our woods and ponds to-day.

f

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