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DESCRIPTIVE CATALOGUE

NAIADES, OR PEARLY FRESH-
WATER MUSSELS

BY
23362
CHARLES TORREY SIMPSON 6.31
PART II
UNIONIDA,
UNIO — NODULARIA .
Division
Seer HOC

BRYANT WALKER
DETROIT, MICHIGAN
1914

MAY 03 1988
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DESCRIPTIVE
CATALOGUE OF THE NAIADES

II.

Genus UNIO Retzius, 1788.

Unio Rerztus, Diss. Hist Nov. Test. Gen., 1788, p. 16.—Bru-
GUIERE, Choix de Memoirs, I, 1792, p. 106—ORTMANN,
mun, Car, Mais, Vili tos. p. 273.

Limnea Poti (part), Test. Utr. Sic., I, 1791, p. 31.

Lymnium Oxen, Lehrbuch, 1815, p. 237.

Elliptio RAFINESQUE, J. de Phys. Nat. Hist., 1819, p. 426.

Mysca ‘Turron, Conch. Ins. Brit., 1822, p. 243.

Canthyria Swainson, Tr. on Moll., 1840, p. 278.

Uniomerus Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 268.
Shell inequilateral, oval to elongated, rounded in front and

pointed or biangulate behind, with a more or less developed

posterior ridge, often becoming slightly arcuate when old;
beaks only moderately full, generally sculptured with coarse
ridges, which run parallel with the growth lines, or are some-
what doubly looped, sometimes broken, and showing fine radi-
ating lines behind; surface smooth, slightly concentrically
ridged or pustulose; epidermis generally rather dull colored,
ravless or feebly rayed; hinge plate narrow; two pseudocardi-
nals and two laterals in the left valve and one pseudocardinal
and one lateral in the right, with rarely a vestige of a second
lateral; cavity of the beaks not deep or compressed. Animal
having the inner branchize free from the abdominal sac for
from one-half to their entire length; marsupium occupying the

528 UNIO

whole length of the outer gills only, forming a thick, smooth
pad when filled with young; gills united to the mantle behind
to their extreme points, or very nearly so; branchial and anal
openings unbranched ; superanal opening always closed below.

Type, Unio tumidus Retzius.

The above generic description applies to the great majority
of the species I have retained under the name Unio.

The genus was described in a thesis by Laurentius Munter
Philipsson under his master, Retzius, in the University of
Lund, Sweden, and it is often credited to the former. I am
informed by Professor Joh. Chr. Moberg, of Lund, that by a
former law or custom of the university the professor was con-
sidered the author of all papers which a student under him
defended. According to this, Retzius must be credited with the
genus. This law was repealed in Lund in 1852.

Until recently all the species of the family Unionide having
nearly or quite perfect pseudocardinal and lateral teeth were
placed in this great group by most conchologists regardless of
the form or details of structure of the shell or the characters
of the animal. Other species in which the lateral teeth were
not quite fully developed, were placed in Margaritana by some
writers and in Unio by others. After a careful study of the
obvious anatomy of a large number of these forms and minor
shell characters, which seemed-to correspond with anatomical
peculiarities, I became convinced that it would be better to dis-
member Retzius’ genus and did so in the Synopsis. As there
restricted it is still the largest generic group contained in either
of the two families treated, and I have given it practically the
same limits in this work. The forms, which have all four
leaves of the branchiz closely filled with embryos, seem to me to
belong to a somewhat different phylum from those in which
only the outer gills are filled. If von Ihering is correct in as-
suming that the Naiades, which have shells with radial beak
sculpture and embryos in the inner gills alone, are the primi-
tive forms, then it would seem reasonable that those that con-
tain them in all four gills represented a step higher in the
development of these forms, the highest type of Unione life

UNIO 529

having the young only in the outer gills. Those forms that
have all four of the gills used as a marsupium have generally
shorter, solider, more inflated shells than those with the em-
bryos in the outer gills alone, and their beak sculpture is
coarser and approaches more nearly to the radial pattern.

The Oriental forms with zigzag beak sculpture and the South
American species whose beaks are marked with radial bars,
all of which, I believe, contain the young in the inner gills
alone, are still wider separated from the true Unios, even
though they may have perfect teeth.

In so large and widely distributed a group as even the
restricted genus Unio there is much diversity of form and
structure. Generally the shell is more or less elongated, but
such species as U. littoralis and some of its allies are short,
being subrhomboid or nearly orbicular. Unio crassidens is
sometimes as ponderous as any of the species of Quadrula. U.
pictorum and some related forms have a bright, even some-
what rayed, epidermis. There is much diversity in the beak
sculpture and some forms have a small upper pseudocardinal
in the right valve.

Section LymMNium Oken, 1815.

Lynmnium OxKen, Lehrbuch, 1815, p. 237.

Shell generally smooth; beak sculpture broken, often some-
what corrugated or pustulous; pseudocardinals compressed ;
beak cavities well excavated, not compressed. Animal highly
colored; anal opening crenulate or smooth.

Type, Unio pictorum Linnzus.

Group of Unio pictorum.

Shell inflated, elongate, oval; anterior end angled above,
swollen a little at posterior base; beaks full, their sculpture con-
sisting of numerous slightly doubly-looped bars, which often
become pustulous; posterior ridge rather low; epidermis
smooth, rather bright, sometimes slightly rayed behind; rest
periods well marked; pseudocardinals compressed, often a lit-

530 UNIO

tle reflexed, smooth below, those of the left valve partly unit-
ed; muscle scars smooth; nacre whitish to salmon. Animal
the same as described for the section.

Unto picroruM (Linnzeus ).

Shell elongated, convex to subinflated, inequilateral, sub-
solid; dorsal and ventral lines nearly parallel; anterior end
rounded or subtruncate, usually slightly angular above; pos-
terior ridge full and rounded, ending behind in a point about
at the median line; the outline of the base is generally a little
angulated at some distance in front of the posterior end; beaks
full and elevated, their sculpture consisting of double-looped
ridges, the anterior loop rounded, the posterior one angled,
the ridges in a majority of cases more or less broken into nod-
ules, which are often scattered; surface nearly smooth, show-
ing only delicate growth lines; epidermis bright, greenish-yel-
low, yellowish-green, straw-color, yellow or tawny, occasionally
feebly rayed behind and in most cases showing the dark rest
periods; left valve with two compressed pseudocardinals, the
hinder sometimes partly double and extending forward below
the anterior one, with two delicate, straight laterals, the lower
the larger; right valve with two compressed pseudocardinals,
the upper much smaller and one high, lamellar lateral; beak
cavities moderately deep; nacre silvery-white, sometimes flesh-
color or salmon, a little thicker in front; muscle scars nearly
smooth, impressed in solid shells.

Length 100, height 43, diam. 30 mm.

Length 80, height 34, diam. 23 mm.

Europe generally ; Siberia east to the Lena River and per-
haps farther; south into Asia Minor?; Algiers?

Mya pictorum Linnatus, Syst. Nature, toth ed., 1758, I, p.
671. PENNANT, ‘Brit. Zool; -1 V7.2 ap). Ee li
Da Cosra). Hist...Nat.. Brit., 1778; ps 228, (plex nese
ScHROTER, Flussconch., 1779, p. 178, pl. 11, figs. 2, 4, 5.—
Sturm, Deuts. Faun., VI, 1803, 2d ed., p. 19, pls. a, b, ¢—
Woop, Gen. Conch., I, 1815, p. 104, pl. xrx, figs. 3, 4; Index
Test..1825, 1p. 12) ply mm, fig. 26c; reve ed 1650, p. 05, pl. um;
fig. 26.—? CuEnu, Bib. Conch., 1st ser., I, 1845, p. 1414, pl.
114, pl. xivit, figs. 8, 9.

UNIO 531

Unio pictorum Rerzius, Diss. Hist. Nat., 1778, p. 17.—Dra-
PARNAUD, part. Hist. Moll. Fr., 1806, p. 131, pl. iy ee
Brarp, Hist. Cog. Paris, 1815, Pp. 226, pl. vil, fig. t.—
Brookes, Int. to Conch., 1815, p. 51, ple typ fe. 12-_C.
Prerrrer, L, and Suss. Moll., Pt. 1, 1821, p. 115, pl. v, figs.
9, 20.—Bosc, Hist. Nat.-Coq., LIL, 1824, p. 139; ply xalEL,
fig. 3—BLaAtNviLLE, Manual, Mal., 1825, p. 539, pl. LXvII,
fig. 2.—CROUCH, Ill. Int. Lamarck, 1827, p. 16, pl. Ix, figs.
4, 44, 4b.—ROSSMASSLER, Icon., Pt. 1, 1835, p. 118, pl. 111,
figs. 71, 71a, 710; III, 1836, p. 23, pl. xiur, fig. 196; VI, 1837,
p. 55, pl. xxix, fig. 409; IX, 1839, p. 10, pl. xLv,, fig. 587-
590; XI, 1842, p. 14, pl. LV, fig. 741; XII, 1844, p. 30, pl.
LvIt, figs. 762-766; p. 31, pl. Lix, figs. 767-769.—F LEMING,
Moll. Animals, 1837, pl. xiv, fig. 51.—WyYAtT, Man. Conch.,
1838, p. 67, pl. vit, fig. 6.—?Gras, Moll. Isere., 1840, p. 71,
pl. 1, fig. 8.—STABILE, Faun. Lug., 1845, p. 60, pl. 1, fig. 73.
—Brown, L. and F. W. Conch., 1845, p. 107, pl. xix, figs.
I-4.— STEIN, Die Lebend. Schneck., 1850, p. 104, pls. XXIV,
xxv, figs. I, 2—MIDDENDORFF, Sib. Reise, II, 1851, p. 276,
pl. xxvut, figs. 1-3—Duruy, Hist. M. Fr., 1852, p. 647, pl.
xxvi, fig. 20.—Forpes and HaNLry, Hist. Brit. Moll., IT,
1853, p. 142, pl. xxxIx, fig. 1.—Kuster, Conch. Cab. Unio,
1854, p. 88, pl. xxuI, figs. I, 2; pl.. xx1v; xxv, figs. I, 2.—
Moourn-Tanpon, Moll. Terr. Fluv. Fr., H, 1855, P. 576,
pls. L, figs. 8, 10; LI, figs. I, 10.—NORDENSKIOLD and Ny-
LANDER, Fin. Moll., 1856, p. 83, pl. v, fig. 72.—DrouEt, Nay.
Fr., II, 1857, p. 103, pl. vit.—Turton, Man. L. and F. W.
Shells, 1857, p. 279, pl. 1, fig. 11.—H. and A. Apams, Gen.
Rec. Moll., II, 1857, p. 491; III, pl. cxv1, figs. 5, 5a, 5b.—
Sowerby, Ill. Index Brit. Shells, 1859, No. 2, pl. vi1.—Goop-
ricu, Ill. Nat. Hist., II, 1859, p. 523, fig —REEvE, i. and
W. Moll. Brit., 1863, p. 221, fig. 2—Tarte, L. and F. W.
Moll. Brit., 1866, pl. 11, fig. 3—Cresstn, Deutsche Ex. Moll.,
1876, p. 453, fig. 294.—L. ADAMS, Coll. Man., 1884, p. 18,
pl. 1, fig. 11.—SmmPpson, Syn., 1900, p. 680.

Baphie pictorum MruscHen, Mus. Gevers., 1787, p. 472.

Lymnium pictorum Oxen, Lehrb., TOES Pp. 237:

532 UNIO

Mysca pictorum Turton, Man. Shells, Brit. Is., 1831, p. 20,
fie. LI.

Margarita (Unio) pictoruwm LEA, Syn., 1836, p. 36; 1838, p. 24.

Margaron (Unio) pictorum Lea, Syn., 1852, p. 36; 1870, p. 58.

Mya angusta subflava, etc., SCHROTER, Fluss. Conch., 1779, p.
184, pl. 11, fig. 3; pl. 1v, fig. 6.

Mya nodosa GMELIN, Syst. Nat., 13th ed., 1788, p. 3222.—
Woop, Ind. Test., 1825, p. 12, pl. 1, fig. 34a; rev. ed., 1856,
p. 16,(pl-eir hies34:

? Unio conus SPENGLER, Skriv. Selsk. Nat., III, 1793, p. 60.

Mya ovalis Donovan, Brit. Shells, III, 1801, pl. yxxxvi.

? Unio ovalis Sowersy, Rec. and Foss. Shells, No. XVI, 1823,
fig —? Reeve, Conch. Syst., I, 1841, p. 117, pl. Lxxxvu, fig.
1.—CHENU, Bib. Conch., 1st ser., I, 1845, p. 67, pl. xxiv,
figs, 1-3. ;

Mya nodulosa Woop, (part), Gen. Conch., I, 1815, p. 106, pl.
KIL, f1es.. 354

Unio nodulosa LAMARCK, An. sans Vert., VI, 1819, p. 78.

Unio rostrata LAMARCK, An. sans Vert., VI, 1819, p. 77.—C.
PreIFFrer, Nat. Deuts. L. and Suss. Moll., Pt. 1, 1821, p. 114,
pl. v, fig..8.—MicHaup, Comp. Hist. Moll. Fr., 1831, p. 108,
pl. xvi, fig. 25.—Brown, L. and F. W. Conch., 1836, p. 109,
pl. xx, figsvie72;; Ill, Ree: Conch: 4844, p: 82) pir xxxir nes:
g-12.—Gras, Moll. Isere., 1840, p. 71, pl. v, fig. 21.

Unio rostratus CHENU, Man., II, 1859, p. 137, fig. 658.

Unio manca LAMARCK, An. sans Vert., VI, 1819, p. 80.

Unio mancus Drover, Moll. Cote d’Or, 1867, p. 103.

Unio limosus Niisson, Hist. Moll. Svec., 1822, p. 110.—Ross-
MASSLER, Icon., III, 1836, p. 24, pl. x11, fig. 199.—KUSTER,
Conch. Cab. Unio, 1854, p. 80, pls. XXI, XXII, XXIII.

Unio deshavesii MicHaup, Comp. Hist. Moll. Fr., 1831, p. 107,
pl. xvi, fig. 30.—Rossmasster, Icon., III, 1836, p. 23, pl.
xi, fig. 197—Brown, Ill. Rec. Conch., 1844, p. 81, pl.
xxxu, figs. 1-4; L. and F. W. Conch., 1845, p. 108, pl. xx,
figs. 3, 4.

Unio dubins Frtzincer, Syst. Verz., 1833, p- 119.

UNIO 533

Unio michaudiana Des Mou ins, Actes Soc. Linn. Bord., VI,

1833, p. 27, plate.

Potamida sicula Swainson, Treatise on Mal., 1840, p. 282,

fis: 58:

Unio siculus HAN zy, Biv. Shells, 1856, p. 383, pl. xx, fig. 19.
Unio arade Puiiarr1, Enum. Moll. Sic., Il], 1844, p. 49.—

Kuster, Conch. Cab. Unio, 1854, p. 105, pl. xxvirt, fig. 6.—

KoseE.t, Icon., IV, 1876, p. 62, pl. cxvu, figs. 1146, 1147.
Unio dactylus MoreLet, Moll. Port., 1845, p. 110, pl. xiv, fig. 2.

Kose rt, Icon., new ser., VI, 1893, p. 98, pl. cxxx, fig. 1132.
Unio mucidus More.er, Moll. Port., 1845, p. 111.—KoBeE.r,

Teon. new. ser, VL, 1893; p: 68, CLXXX, figs. 1130, 1131.
Unio quinqueannulatus KustTER, Conch. Cab. Unio, 1854, p. 93,

pl. xxv, figs: 3,4.

Unio pallens Kuster, Conch. Cab. Unio, 1854, p. 95, pl. xxv,
fie) 5X MVE, hie. Te ;
Unio wiridiflavus Kuster, Conch. Cab. Unio, 1854, p. 96, pl-

Rev, figs) 25°39:

Unio petroviciti Kuster, Conch. Cab. Union, 1854, p. 98; pl.

RVI, fig: 5; Xxvit, fig. 1.

Unio maltzani Kuster, Conch. Cab. Unio, 1854, p. 106, pl.

EXEN, MISS: f° 2:

Unio baletonicus KustEer, Conch. Cab. Unio, 1861, p. 231, pl.

RR RVILI STs
Unio proechus Bourcutcnat, Rev. et Mag., XIV, 1862, p. 19,

pl. x1x; figs: 1-3.

Unio actephilus Bourcuicnat, Rev. et Mag., XIV, 1862, p. 20,

Bi xixehose7, S: pl, xx, fig. 2.

Unio lawleyanus GENTILUOMO, Bull. Mal. Ital., I, 1868, p. 54,

pl. tv, figs. 1-3.

A species having a wide distribution and one that is abun-
dant, yet it does not seem to me to be especially variable or
that there is the slightest necessity for the great number of
names, which have been bestowed upon it. It is an elongated,
rather cylindrical, bright colored and rather smooth form, us-

234 UNIO

ually a little higher in front than behind and subangular or
very slightly produced on the base line just back of the middle
of the shell.

Hanley says of this species [Ipse Linnzei Conchylia, p. 27] :
“More uniones than one are present in the | Linnean] collec-
tion, but upon the whole the U. pictorwm of authors | Rossm.
Icon., fig. 196] agrees best with synonymy and description.
The figure referred to of Lister is U. pictorum; Bonanni’s
drawing is more doubtful and was possibly meant for U. tumi-
dus. The descriptions in Fauna Suecica and Systeme are
brief and unsatisfactory and might suit either species alike.”

Var. /ongirostris Rossmassler.

Shell greatly elongated, olive, brown, or dirty yellowish-
green.

Length 70, height 28 mm.
Unio longirostris RossMASSLER, Icon., III, 1836, p. 26, pl.

Xiv, fig: 200; X11, 1842, p. 13¢pl, rv, fist 738:
Unio pictorum (part), SIMPSON, Syn., 1900, p. 682.

This form may possibly be worthy of varietal rank. It
seems to be smaller than the ordinary manifestation of the
species, is more elongated and duller colored and lacks rays.

UNIO PLATYRHYNCHUS Rossmassler.

Shell elongated, subinflated, inequilateral, rather thin to sub-
solid, dorsal and ventral lines parallel, anterior end subtruncat-
ed, pointed above; posterior end compressed and curved down-
ward into a decided beak, which usually extends below the
base line; beaks full, slightly elevated, their sculpture consist-
ing of corrugated ridges, which break up into nodules, which
are strongly developed on the posterior ridge; posterior ridge
rounded ; surface with irregular growth lines; epidermis finely
folded along the growth lines, generally smooth on the middle
of the disk, rough behind, dirty greenish to burnt-brown;; left
valve with two greatly compressed pseudocardinals, which are
sometimes united, and two delicate, straight, lamellar laterals,

UNIO 5am

the lower higher; right valve with two compressed pseudocar-

dinals, the upper small, and one high lateral; nacre bluish-

white, usually rather dull, thickened a little in front.

Length 68, height 26, diam. 18 mm.

Central and southwestern Europe.

Unio platyrhynchus RossMASSLER, Icon., LI, 1835, p. 22, pl. 1x,
fig. 130; V, 1837, p. 20, pl. xxiv, fig. 338.—HAanL_Lgy, Biv.
Shells, 1843, p. 205, pl. xx111, fig. 53.—Kuster, Conch. Cab.
Unio, 1854, p. 77, pls. x1x, xx.—SowersBy, Conch. Icon.
XVI, 1856, pl. xxx, fig. 154.—Srmpson, Syn., 1900, p. 683.

Margarita (Unio) platyrhynchus Lea, Syn., 1836, p. 35; 1838,
p. 24.

Margaron (Unio) platyrhynchus Lea, Syn., 1852, p. 36; 1870,
p. 58.

Umo fiscallianus Kieciacu, Atti. Soc. Ital., XV, 1872, p. 92.
—PFEIFFER and Koper, Mal. Blatt., XX, 1873, p. 92, fig.
Unio limosus Kopett, Icon., new ser., VI, 1893, p. 44, pl.

CLVII, figs. 1024-1027.

A most distinct and peculiar species, always distinguishable
when adult by the curious, compressed beak at the hinder base..
Generally the surface is roughened and dull, though the earlier
growth is bright and smooth, and until it is near maturity the
shell is almost exactly like a young, delicate pictorum.

UNIO PLATYRINCHOIDEUS Dupuy.

Shell elongated, subinflated, somewhat ovate or rhomboid,
inequilateral, subsolid; beaks full, rather high, their sculpture
consisting of fine, doubly-looped, nodulous ridges; posterior
ridge high, angled, somewhat double below ; anterior end sub-
truncate, angled above; posterior slope obliquely truncated,
plicately corrugated ; surface otherwise nearly smooth, having
faint growth lines and obsolete radial sculpture anteriorly ;
epidermis shining, olive-green to burnt-brown, showing the
dark rest periods; left valve with two compressed pseudocar-
dinals, which are almost united into one, and two curved, deli-
cate laterals; right valve with two pseudocardinals, the lower

536 UNIO

the larger, and one lateral; beak cavities rather deep, nacre

bluish or flesh-white, dull, a little thicker in front.

Length 107, height 48, diam. 35 mm.

South France.

Unio platyrinchoideus Duruy, Cat. Ext. Gall. Test., 1849 ; Hist.
Moll. Fr., VI, 1852, p. 649, pl. xxvii, fig. 16.—?DROUET,
Nay. Fr., II, 1857, p. 100, pl. rx, fig. 1—Srmpson, Syn.,
1900, p. 684.

Unio platyrhynchoideus WrSTERLUND, Faun. Pal. II, Pt. 7,
L890; p. 121.

Unio platyrrhynchoideus SowERBY, Conch. Icon., XVI, 1868,
pli Exx, fies 258.

Unio dantelis Gasstrs, Actes. Soc. Linn. de Bord., XXVI,
1866, -p.- 132, pla, ie. 8.

Unio lardehanus Preccutiort, Bull. Mal. It., H, 1869, p. 163,
pl. v.

Perfectly distinct from U. pictorum and allied species. The
differential characters are the somewhat biangulate and drawn-
out posterior end, the faint radial sculpture anteriorly, the
plications on the posterior slope and the doubly-looped, fine
beak sculpture. The shell is often almost sinuate just behind
the middle of the base.

UNIO ELONGATUI,US C. Pfeiffer.

Shell elongated, thin to subsolid, subovate or subelliptical,
subcompressed, inequilateral, beaks neither full nor high, their
sculpture consisting of numerous fine, doubly-looped ridges,
which are slightly nodulous at the bases of the loops; posterior
ridge low, ending at or below the median line in a feeble bian-
gulation; base line sometimes a little sinuate in the middle;
anterior end rounded; surface nearly smooth; epidermis ashy-
greenish or ashy-brownish, shaded with yellowish, subshin-
ing, rayless; left valve with two distinct, compressed pseudo-
cardinals and two delicate, slightly curved laterals; right valve

UNIO 537

with two pseudocardinals, the upper small, and one lateral;

nacre bluish-white, a little iridescent behind, thickened in front.

Length 60, height 27, diam. 15 mm.

Length 55, height 28, diam. 15 mm.

Central Europe.

Unio elongatula C. PFEIFFER, Nat. Deuts. L. and S. Moll., II,
1825, p. 35, pl. vul, figs. 5, 6.

Unio elongatulus RossMAssuER, Icon., IT, 1835, p. 23, pl. 1x,
figs rs2) Ale 18445. 27, pl. ivi, fig. 757: V1;\1870; p. 42,
pl. cLxu, figs. 1644, 1645——Kustrr, Conch. Cab. Unio, 1854,
p. 104, pl. xxvutt, figs. 4, 5—Drouer, Nay. Fr., IT, 1857, p.
gI, pl. vi, fig. 2—SowerBy, Conch. Icon., XVI, 1868, pl.
LXXXV, fig. 451.—Srmpson, Syn., 1900, p. 684.

Margarita (Unio) elongatus Lea, Syn., 1836, p. 37.

Margarita (Unio) elongatulus Lea, Syn., 1838, p. 24.

Margaron (Unio) elongatulus Lea, Syn., 1852, p. 37; 1870, p.
59-

More delicate and compressed, smaller and a trifle more bi-
angulate behind than U. pictorum, yet it may be only a variety
of it. The beak sculpture is not so nodulous and the pseudo-
cardinals of the left valve are more distinct than in Linnzeus’
species.

UnIo TUMIDUs Retzius.

Shell long ovate, being wide in front and gradually narrowed
and drawn out to a point on the median line behind, subsolid
to solid, subinflated, inequilateral; beaks moderately full and
high, their sculpture consisting of uneven nodulous or sub-
nodulous ridges, which are corrugated and generally doubly
looped ; posterior ridge subangular but not high, placed near
the dorsal line of the shell; surface almost smooth, with scat-
tered growth lines; epidermis bright and shining, greenish-
yellow, yellowish-green, ashy or reddish-brown, often some-
what rayed; left valve with two compressed, ragged pseudo-
cardinals and two delicate, nearly straight laterals; right valve
with one pseudocardinal, with sometimes a vestige of another

538 UNIO

above it, and one lateral ; beak cavities moderately deep; nacre

whitish or bluish-white, not’brilliant, thickened a little in front.
Length 113, height 52, diam. 39 mm.

Length 77, height 40, diam. 25 mm.
Northern and middle Europe; eastern Siberia.

Unio tumidus Rerzrus, Diss. Hist. Nat., 1778, p. 17,—Ross-
MASSLER, Icon., I, 1835, p. 117; pl. Mm fisse 70, 70a, 70mm Uk
1836, p. 27, pl. xiv, figs. 202-2043 VATE I638ep ey pleet
fig. 543; XII, 1844, p. 32, pl. Lx, figs. 772-778.—Brown, L.
and F. W. Conch., 1836, p. 109, pl. xx1, figs. 8, 9 —Brown,
Ill. Rec. Conch., 1844, p. 82, pl. xxxm, figs. 5-8.—STABILE,
Faun. Lug., 1845, p. 61, pl. 11, fig. 74.—Dupuy, Hist. Moll.
Fr., 1852, p. 655, pl. xxvi, fig. 20—Forses and HANLEY,
Hist. Brit. Moll., I], 1853, p. 140, pl. x1, fig. 1.—KUSTER,
Conch. Cab. Unio, 1854, p. 71, pls. xvi, xvi1.—MoguIn-
Tanpon, Moll. Terr. Fluv., II, 1855, p. 577, pl. 11, figs. 11,
14.—NORDENSKIOILD and NYLANDER, Fin. Moll., 1856, p. 85,
pl. v1, figs. 7, 8—Drouet, Nay. Fr., II, 1857, p. 110, pl. rx,
fig. 2—Sowerpy, Ill. Int. British Shells, 1859, pl. vi1, No. 3-
—Rereve, L. and F. W. Moll. Brit., 1863, p. 210, fig. 1.—
Reeve, Conch. Icon., XVI, 1865, pl. xxv, fig. 124.—TarTE,
L. and F. W. Moll. Brit., 1866, pl. 11, fig. 2—Ct1xssin, Deuts.
Bx. Moll., 1876, p. 458, fig. 299.—L. Anams, Coll. Man.,
1884, p. 18, pl. L, fig. 1o—Koserwt, Icon., new ed., VI, 1893,
p. 87, pl. cLxxul, fig. 1115.—S1mpson, Syn., 1900, p. 684.

Margaron (Unio) tumidus Lua, Syn., 1852, p. 36; 1870, p. 58.

Unio tumida C. Prreirrer, Nat. Deuts. L. and S. Moll., I,
1925, p: 34, pl. vu, figs. 2, 33 pl vit, nese

Mya depressa Donovan, Brit. Shells, ITI, 1801, pl. cr.—
CHenv, Bib. Conch.; 1st Ser. 1, 1645p ie pln sex sess
1-3.

Unio depressus Paret,, Conch. Sam., IIT, 1890, p. 150.

Mya ovata Donovan, Brit. Shells, IV, 1802, pl. cxx11.—Woop,
Gen. Conch., I, 1815, p. tos, pl. xrx, fig. 5; Ind. Test., 1825,
p. 12, pla, fig 27c. rev. ed., 1856, py aio pln mene eye
CuEnu, Bib. Conch., 1st Ser., I, 1845, p. 82, pl. xxxu1, figs.
1-3.

UNIO 539

Mysca ovata Turton, Conch. Ins. Brit., 1822, p. 246; Man.
Shells Brit. Is., 1831, p. 21, fig. 12—Swatnson, Treat. on
Mal., 1840, p. 277, fig. 56.

Mysca solida ‘Turron, Conch. Ins. Brit., 1822, p. 246, pl. xvi,
fig: 2; Man. Shells Brit. Is., 1831, p. 22, fig. 13.

Mya ovalis Monracu, Test. Brit., 1803, p. 34.

Unio ovalis Brown, L, and F. W. Conch., 1836, p. tor, pl. xvii,
nese: ilokec: Conch. 1644, p82, pl. xxx, figs. 12-14.

Margarita (Unio) ovalis Lra, Syn. 1836, p. 35; 1838, p. 24.

Unio muelleri RossMASSLER, Icon., VIII, 1838, p. 41, pl. x1, fig.
BAT el loq2. pet, pl. Liv, fie 730,

Umio pictorum Brown, Ill. Rec. Conch., 1844, p. 81, pl. xxx1,
figs. 8-11.

Close to U. pictorwm and in some cases it is well nigh im-
possible to separate it from that species. In general it is not
quite so elongated ; it is wider in proportion in front and nar-
rower behind. There is sometimes a slight fulness in the pos-
terior basal outline just behind the middle, but this is not so
common or so pronounced as in pictorum. Occasionally the
posterior point is elevated a little so that it will be found a
trifle above the median line. "The muscle scars are nearly
smooth, shallow in thin shells, and well impressed in solid
ones. ‘The anterior end is often subtruncated and _ slightly
angled above.

Unto TuRTONI Payraudeau.

Shell oblong, inclined to be slightly rhomboid, convex to
subinflated, subsolid, rounded in front and rarely angled above,
inequilateral; beaks slightly elevated, moderately full, their
sculpture variable, consisting of a few corrugated, subnodu-
lous ridges that show a tendency to be doubly looped; some-
times the sculpture is faint and reduced to a few nodules;
surface nearly smooth; epidermis pale yellowish-ash, ashy-
brown, greenish below, yellowish-green or sometimes almost
olive, usually rayless and showing the dark rest periods dis-
tinctly ; left valve with two compressed, ragged pseudocardi-

540 UNIO

nals that are often almost united, and two curved, diverging

laterals ; right valve with two pseudocardinals, the upper feeble,

and one lateral; beak cavities not deep; nacre whitish usually
tinted with flesh-color, straw or salmon, slightly thicker in
front; muscle scars smooth, not deep.

Length 68, height 34, diam. 20 mm.

Length 62, height 30, diam. 20 mm.

Entire circummediterranean region.

Umo turtont PAYRAUDEAU, Cat. Moll. Corse, 1826, p. 65, pl.
i, fig. 65.—RossMASSLER, Icon., VII, 1838, p. 25, pl. xxxv,
fig 492.—Dupvy, Hist. Moll. Franc. 1852, p. 651, pl. xxvu,
fig. I17.—SIMPSON, Syn., 1900, p. 685.

Unio capigliolo PAYRAUDEAU, Cat. Moll. Corse, 1826, p. 66, pl.
11, fig. 4——RossmMassiErR, Icon., V and VI, 1837, p. 22, pl.
XXIV, fig. 341; XII, 1844, p. 28, pl. tv, figs. 755, 756.—
Mogutn-Tanpon, Moll. Terr. Fluv. Fr., II, 1855, p. 574,
plz, fist

Unio capigliolo var. bandimi Parren, Conch. Sam., III, 1890, p.
147.

Unio pictorum GuxrrRin, Icon. Regne Anim., II, 1829-1844, pl.
xxvul, fig. 16.—Bourcuicnat, Mal. Alg., II, 1864, p. 292,
pl. xxu, figs. 6-11.—ReEEvE, Conch. Icon., XVI, 1865, pl.
XXV, fig. 123.

Unio requienii MicHaup, Comp. Hist. Nat. Moll. Fr., 1831, p.
106, pl. xvi, fig. 24.—Rossmassier, Icon., III, 1836, p. 24,
pl. xu, fig. 198.—Stapirx, Faun. Lug., 1845, p. 62, pl. m1,
fig. 1786.—Gasstes, Moll. Agen., 1849, p. 195, pl. 1, figs. 4,
s.-—Dupvy, Hist. M. Fr., 1852, p. 652, pl. xxvu, fig. 18.—
Kuster, Conch. Cab. Unio, 1854, p. 126, pl. xx1, fig. 7; X XVI,
figs. I-3; Xxxvut, figs. 2-4——Drovet, Nay. Fr., II, 1857, p.
93, pl. vu, figs. 1-3.

Unio lobata Putriprt, Moll. Sic., 1836, p. 67.

Unio bandinii RossMAsstEr, Icon., V, 1837, p. 22, pl. xx1Vv, fig.
341.

UNIO 541

Unio pallens RossMASSLER, Icon., XI, 1842, p. 13, pl. Liv, fig.
749.

Unio hispanus Rossmassier, Icon., XII, 1844, p. 26, pl. iv1,
fig. 747.—Bourcuienat, Moll. Peu. Con., 1863, p. 46, pl.
XXIV, figs. 1-3; Rev. et Mag., XVII, 1865, p. 344, pl. xxi,
figs. 1-3.

Unio aleroni CoMPANYO and Massor, Bull. Soc. Pyr. d’Or, VI,
Pt. 2, 1845, p. 234, fig.—Bourcuicnat, Moll. Peu. Con.,
1863, p. 49, pl. xxin, figs. 1-3; Rev. et Mag., XVII, 186s,
pixie figs. 13

Unio ravoisieri DesHAyus, Hist. Nat. Moll. Aceph. Alg., 1848,
pl. evi, figs. 4-7—Bourcuicnat, Mal. Alg., 1864, p. 291,
pl. xx, figs. 5-10.—Simpson, Syn., 1900, p. 687.

Margaron (Unio) ravoisieri Lea, Syn., 1870, p. 48.

Unio ravoisiert var. tssericus Koper, Icon., new ser., I, 1884,
p.i65, pl. XXVilt, fis. 215.

Umo rousu Dupuy, Hist. Moll., VI, 1852, p. 653, pl. xvuut,
fig. 18.—Muscrave, Phot. Conch., 1863, pl. 1, fig. 7.

Unio valentinus RossMASSLER, Icon., IIT, 1854, p. 37, pl. LXIXx,
p. 852.—Bourcuicnar, Moll. Peu. Con., 1863, p. 45, pl.
ReOWEE Rew. cto Mass Zook, XVI; 1865; p..343,- pl xx

Margaron (Unio) valentinus Lea, Syn., 1870, p. 52.

Unio ardusianus Mogutn-Tanpon, Hist. Moll. Fr., II, 1855,
P. 575-

Unio graellsianus BourcuIGNAT, Moll. Peu. Con., 1863, p. 47,
pl. xxut, figs. 4-7; Rev. et Mag., 1865, p. 345, pl. x1x, figs.
4-7.

? Umio letourneuxit BourcuicNat, Mal. Alg., 1864, p. 280, pl.
Xvit, fig. 47.

Unio courguimianus Bourcuicnatr, Moll. Peu. Con., 1863, p.
48 ; part, Rev. et Mag., 1865, p. 346, pl. xxu1, figs. 1, 2.

Unio siculus Sowrersy, Conch. Icon., XVI, 1868, pl. Lxx1, fig.
264.

Unio alexandri Korrvt, Icon., tst sup., 1895, p. 14, pl. 1,

fig. 2.

542 UNIO

A widely distributed circummediterranean form, which,
though somewhat variable in minor characters, 1s reasonably
constant. Of course every possible variation has received
specitic names and often a single form has been repeatedly
named. It differs from U. pictorum and U. tumidus, its near-
est allies, by being almost constantly somwhat rhomboid, the
base line being almost straight. Usually the texture differs
a little from that of either of those species but this difference
is hard to describe in words. It is perhaps a little more smoky
externally and the rest periods are usually more plainly marked.
A careful comparison of material received since the Synopsis
was written convinces me that the Unio ravoisieri of Deshayes
is only a rather dark U’. turtoni, which is not so rhomboid as
the majority of specimens of that species.

Var. moreleti Deshayes.

Shell Jarger than the average manifestation of U.. turtoni;
epidermis brownish, dirty yellowish or yellow-green.

Length &6, height 37, diam. 22 mm.

Algiers.

Unio moreleti DesHayes, Hist. Moll. Alg., 1848, pl. crx, figs.
1-4; pl. cxu, fig. 5—JKoret, Icon., new ser., II, 1886, p. 4,
pl. XcRae 226.

Margaron (Unio) moreleti Lea, Syn. 1870, p. 60.

? Unio maccarthyanus BourcuicNat, Moll. Nonv. Litis., 1886,
p. 220, pl. xxxtv, figs. 8-11.

Unio ravoisieri, (part), Simpson, Syn., 1900, p. 687.

I have seen two lots of shells bearing the name Unio more-
leti from the Morelet collection; one from Orleansville, Al-
giers, is U. turtoni pure and simple, the other, a single shell
from La Calle, Algiers, is much like Deshayes’ figure of more-
leti and is probably a variety of turtont.

UNIO MUSSOLIANUS Kuster.

Shell oblong, elliptical, solid. subinflated or inflated, inequi-
lateral; beaks full and elevated, their sculpture consisting of
rather faint corrugated, somewhat doubly-looped ridges, but

UNIO h 543

it is sometimes reduced to a few nodules; posterior ridge faint-

ly narrowly double ending behind in a feeble biangulation

about on the median line; anterior end rounded, not angled
above: surface smooth or slightly concentrically grooved, fus-
cous olivaceous or tawny, sometimes pale yellowish-green or
greenish-yellow ; the rest periods usually well marked, sub-
shining: left valve with two subcompressed pseudocardinals
and two laterals, the lower club-shaped; right valve with one
pseudocardinal and a vestigial one above it, with one lateral;
beak cavities not deep: nacre silvyery-white, a little thicker in
front ; anterior scars deep.

Length 54, height 29, diam. 23 mm.

J,ength, 49, height 27, diam. 18 mm.

Length 79, height 44, diam. 33 mm.

Assyria.

Unio mussolianus WusterR, Conch. Cab. Unio, 1851, p. 244. pl.
LXXXU, fig. 1-—SrmMpson, Syn., 1900, p. 687.

Unio bourgugnatianus, Lea, Pr. Ac. N. Sci. Phila., VII, 1863,
Deteo enc MN pcr hilas, VI, 1866, p> 54, pl. xvrt, fig.
51; Obs. XI, 1867, p. 55. pl. xvii, fig. 51.—-Kosett, Icon.,
new ed., XVIII, 1912, p. 48, pl. piv, fig. 2661.

Margaron (Unio) bourguignatianus Lea, Syn. 1870, p. 39.

Umavrasns, Lets Pr Ac. N: Sci. Phila: sViIl, 1863, p. 18979)
Acad. N. Sci. Phila., VJ, 1866, p. 50, pl. xvi, fig. 47; Obs.
XI, 1867, p. 54, pl. xvi, fig. 47.—Korext, Icon., new ed.,
AVIII, 1912, p. 47..pl. p11, fig. 2660.

Margaron (Unio) rasus Lea, Syn., 1870, p. 58.

Umio mosulensis Lea, Pr. Acad. N. Sci. Phila., VII, 1863, p.
190; Jl. Acad. N. Sci. Phila., VI, 1866, p. 52, pl. xv, fig. 49:
Obs. XI, 1867, p. 56, pl. xvn, fig. 40.

Moargaron (Unie) mosulensis Lea, Syn., 1870, p. 48.

Margaritana mossulensis Pxtet, Conch. Sam., III, 1890, p.
173.

Unio mossulianus Koprir, Tcon., new ed., XVIII, 1912, p. 46,
pl. piu, fig. 2658.

I have united a number of nominal species under Kuster’s
name, which seems to be the oldest. His shell, as figured, ap-

544 UNIO

pears a little more sulcate than most of the specimens I have
seen, but it agrees otherwise in all the characters. The species
is more solid, more inflated and less rhomboid than U. turtonz;
it is shorter and more evenly elliptical than U. pictorum or
tumidis.

UNIO MODIOLA Preston.

“Shell elongaiely oblong, somewhat curved, solid, covered
with a chocolate coloured, laminiferous periostracum, both
valves concentrically striate; umbones large, but not promi-
nent, somewhat coarsely corrugate; dorsal margin slightly
arched ; ventral margin curvedly excavated in the median pos-
terior region ; anterior side somewhat produced, rounded above.
sloping below; posterior side produced, rounded; cardinal
teeth rather anteriorly situate, triangular, erect; lateral teeth
anteriorly very short, posteriorly elongate and abruptly ter-
minating; anterior adductor scars deeply impressed; poste-
rior scars slight; interior of shell very slightly iridescent, sculp-
tured with fine, irregular ridges somewhat resembling the
marks of coarse finger prints.

Long. 45, lat. 86 mm.” (Preston).

Type locality, River Tigris.

Unio modiola Preston, Rec. Ind. Mus., VII, 1912, p. 286, pl.

Vit, figs. 1-2.

Unio HUETI Bourguignat.

Shell almost evenly long elliptical, somewhat inflated, sub-
solid, inequilateral ; beaks slightly elevated, not full, their sculp-
ture not known; posterior ridge low, rounded, ending behind
in a rounded point just below the median line; anterior end
rounded ; base line slightly curved; surface decidedly concen-
trically sculptured; epidermis yellowish or fuscous green;
pseudocardinals subcompressed, ragged; laterals long, slightly
curved; anterior muscle scars deep.

Length 68, height 33, diam. 21 mm.

Upper Euphrates in the Pashalic of Ergeroum, Armenia,
Asia Minor.

UNIO 545

Unio hueti Bourcuicnat, Rev. et Mag., VII, 1855, p. 332, pl.
vill, fig. I-4+—-MARYrENS, Vorderas. Conch., 1874, p. 35, pl.
vu, fig. 54.—SIMPSON, Syn., 1900, p. 687.—KoseE.t, Icon.,
new ed., XVIII, 1912, p. 409, pl. piv, fig. 2662.

While this species is close to several others it does not seem
to absolutely connect with them. Its almost evenly long ellip-
tical form and the somewhat delicate but decided concentric
sculpture separate it from U. turtoni, U. tigridis and U. mus-
solianus.

Unio EucirRUs Bourguignat.

Shell almost regularly elliptical, scarcely subsolid, subcom-
pressed, somewhat inequilateral; beaks but little raised, not
inflated, sharp, their sculpture consisting of a double row of
low nodules; posterior ridge low, somewhat double and end-
ing behind in a faint biangulation on the median line; surface
delicately concentrically sculptured, the posterior slope having
apparently slight radial wrinkles; epidermis yellow; pseudo-
cardinals almost lamellar; laterals very delicate and straight ;
nacre white.

Length 50, height 31, diam. 17 mm.

Asia Minor.

Unio eucirrus Bourcutcnat, Mag. Zool., IX, 1857, p. 20, pl.
vit, figs. 4-6.—Koperr, Icon., VII, 1880, p. 82, pl. cevt, fig.
2101.—SIMPSON, Syn., 1900, p. 688.

Margaroen (Unio) eucirrus Lara, Syn., 1870, p. 46.

This has something the outline of U. mussolianus, but is
much less inflated and is a thinner, more delicate shell. The
pseudocardinals seem to be almost lamellar.

It is probably a form of hueti.

Unio ricripis Bourguignat.

Shell somewhat wedge-shaped, being thicker, more inflated
and higher in front than behind, solid, exceedingly inequilater-
al; beaks full and quite high, turned forward over a well

marked lunule, their sculpture varying from a few small pus-
tules to a number of broken, corrugated ridges, which show

546 UNIO

a tendency to break into nodules; anterior end decidedly trun-

cate and angled above in old shells, more nearly rounded in

young ones; posterior ridge close to the dorsal line, ending
behind in a point above the median line ; post-basal part of the
shell a little produced; surface almost smooth, having feeble
growth lines; epidermis yellowish, greenish-yellow, tawny or
brownish, usually showing the rest periods; left valve with
two compressed, often united, pseudocardinals and two curved,
lamellar laterals, the upper small; right valve with a single
compressed pseudocardinal and one lateral; pseudocardinals
somewhat reflexed; beak cavities moderately deep; nacre
white, silvery, thicker in front; anterior scars very deep; pos-
terior scars shallow.

Length 92, height 47, diam. 37 mm.

Asia Minor; Assyria.

Unio truncatus Swainson, Zool. Hl., 2d ser., I, 1829, pl. x.—
SOWERBY, Conch. Icon., XVI, 1868, pl. LX xxv, fig. 453.

Margarita (Unio) truncatus LEA, Syn., 1836, p. 21; 1838, p. 18.

Margaron (Unio) truncatus Lea, Syn., 1852, p. 26; 1870, p. 39.

Unio tigridis Bourcuicnat, Test. Nov. Saul., 1852, p. 30; Cat.
Rais. Moll., 1853, p. 77, pl. iv, figs. 7-9.—Kustrer, Conch.
Cab. Unio, 1861, p. 227, pl. Lxxvu, fig. 1—Kose.r, Icon.,
new ser., I], 1886, p. 2, pl. Xxxu, fig. 226.—SimPpsoN, Syn.,
1900, p. 688.—Koset, fcon., new ed., XVIII, 1912, p. 62,
pl. DX, figs. 2683, 2684.

Umo disnatus. Lea, Pr. Ac: N. Scu Phila., VII, 1863; po 180;
JietAcadIN.;Sei:. Phila., Wi 2866," ps si, plexyueiee or
Obs., XI, 1867, p. 55, pl. xvi, fig. 48—Kose.t, Icon., new
ed., XVIII, 1912, p.. 43, pl. pm, fig. 2654.

Margaron (Unio) dignatus Lea, Syn., 1870, p. 39.

Unio dignatus semiramidis Koper, Icon., new ed., XIX, 1912,
p. 11, pl. pxvit, fig. 2698.

Unio dignatus assuricus Korg, Icon., new ed., XIX, 1912,
p. 13, pl. Dxvitt, fig. 2690.

Unio dignatus ninusi Korver, Icon., new ed., XIX, 1912, p.
13, pl. pxviit, fig. 2700.

Margaron (Unio) tigris Lea, Syn., 1870, p. 39.

UNIO 547

Unio kisonis Kopenr, Icon., tst sup., 1895, p. 17, pl. vu, figs.
eet
Unio ciconius Koeeir, Icon., new ed., XIX, 1912, p. 11, pl.

DXVU, fig. 2697.

Unio medicus Koper, Icon., new ed., XIX, 1912, p. 17, pl.

Dee ee, 2707:

A fine species, which is remarkably inequilateral and in
adult specimens is decidedly truncate in front, hence Swain-
son’s name. It is more or less wedge-shaped whether viewed
from above or from the side; it has a wide, well-marked lun-
ule and very deep anterior scars.

As the name Unio truncatus, which was first applied to this
species by Swainson had been previously used by Spengler
for another Unio in 1793, it was necessary to discard this and
I have applied Bourguignat’s name, which was next applied
to it. Lea's Unio dignatus agrees with Swainson’s figure.

Unto pietri Locard.

Shell somewhat wedge-shaped, inequilateral, convex or sub-
inflated, solid; beaks full and high, placed at some little dis-
tance from the anterior end, their sculpture consisting of fine,
irregular corrugations with two rows of nodules. Anterior
end rounded but angled above; dorsal line nearly straight for
some distance behind the beaks, joining the oblique post-dorsal
truncation at an angle; posterior ridge full, rounded or slight-
ly biangulate, ending behind below the median line in a point
or a feeble biangulation; pseudocardinals subcompressed ; lat-
erals delicate and slightly curved; nacre white or pale rose.

The shell is nearly smooth or somewhat concentrically sul-
cated, and yellowish or yellow-green.

Length 50-77, height 28-31, diam. 20-22 mm.

Length 48, height 24, diam. 19 mm.

Asia Minor.

Unio pietri Locarp, Comptes Rendus, XCI, 1880, p. 500; Arch.
Mus. Lyon, III, 1883, p. 210, pl. xx, figs. 17-19.—SIMPSON,
Syn., 1900, p. 688.

Unio petrot Pater, Conch. Sam., III, 1890, p. 163.

548 UNIO

Unio lorteti Tocarp, Comptes Rendus, XCI, 1880, pe 502°
Arch. Mus; Lyon, Tl, 1883, p. 215, pl xxt nes. 7-12.

Taq 4 , , aval f ~ /

Unio tristranit Locarp, Arch. Mus. Lyon, III, 1883, p. 209, pl.
xX, Mes. 15, 16.

Unto tiberiadensis Locarp, Arch. Mus. Lyon, IIT, 1883, p. 216,
pl. Xx1, figs. 13-15.

Unio prosacrus Locarp, Arch. Mus. Lyon, Ill, 1883, p. 219,
pl. xx1, figs. 16, 17—Kose xt, Icon., new ed., XVIII, 1912,
p. 60, pl. pix, figs. 2679-2681.

Unto axiacus Locarn, Arch. Mus. Lyon, III, 1883, p. 242, pl.
XX, figs. 20-23.

Umio subtigridis Locarp, Arch. Mus. Lyon, III, 1883, p. 245,
pl. xxi; figs. 18-20.—Kopetr, Icon., new ed., XVIII, 1912,
p: 61,<pl. Drx, fie! 2682.

Unio aremprosthus Locarp, Arch. Mus. Lyon, III, 1883, p.
246,01. xxi igs. 21-23.

Unio chantri Locarp, Arch. Mus. Lyon, IU, 1883, p. 247, pl.
KKM, Wessel 7
Loecard may not have applied different specific names to

every specimen he examined from the lakes Tiberias, Antioch

and Honus, but he has evidently named nearly all of them,
and given outline figures. which differ in some trivial detail.

This form seems to differ from Bourguignat’s old U. terminalis

in not having the beaks quite so near the anterior end, in

being angled at the upper anterior part and having an angle
at the hinder end of the ligament from which it is obliquely

truncated.

Unto zABULONICcUs Locard.

Shell subrhomboid, inequilateral, solid, rather inflated ; beaks
full and high, their sculpture not observed ; dorsal line some-
what curved, meeting the oblique truncation of the dorsal
slope with a low angle; posterior ridge ending in a rounded
point at the base of the shell ; base line nearly straight ; anterior
end rounded, angled at its upper part: surface faintly, concen-
trically striate, smoothish, brilliant, yellowish inclining to burnt

UNIO 549

brown or black at the extremities and beaks; pseudocardinals

thick, subtriangular; laterals strong, short and curved; nacre

white, rose-colored in the cavities.

Length 50, height 31, diam. 22 mm.

Lakes Tiberias and Antioch.

Unio zabulonicus Locarp, Arch. Mus. Lyon, II], 1883, p. 220,
pl. xxu, figs. r1-18—Simrson, Syn., 1900, p. 689.—Kosexr,
lcon;, new ed, X VIN, roT2, p..57, pl. pvirt, fig, 2675.

Unio antiochianus Locarp, Arch. Mus. Lyon, III, 1883, p.
240, pl. Xx, figs. 14-16.

This seems to differ from allied species in being more rhom-
hoidal, in its brilliant epidermis, and the peculiar color, yellow-
ish in the middle of the shell and dark at the beaks and ex-
tremities. I cannot see the slightest reason why Locard should
separate the form from I,ake Antioch under another name—
the only difference which seems to exist between them being
that sabulonicus is a little larger.

UNIO TERMINALIS Bourguignat.

Shell beautifully and almost exactly long elliptical, subin-
flated, subsolid, somewhat wedge-shaped when viewed from
above ; beaks full and somewhat elevated above the hinge line,
their sculpture apparently a few fine, uneven corrugations ;
posterior ridge well developed but not elevated, rounded or
feebly biangulate, placed near the dorsal line and ending be-
hind near the median line; surface delicately concentrically
striate ; the posterior slope plicately wrinkled: epidermis pale
yellowish-green, sometimes with one or two darker rays on
the dorsal slope; left valve with two compressed pseudocardi-
nals, which are often united and two delicate laterals; right
valve with one pseudocardinal and one lateral: nacre bluish-
white, subshining.

Length 50, height 28, diam. 19 mm.

Length 52, height 29, diam. 22 mm.

Length 54, height 27, diam. 22 mn.

T.ake Tiberias.

55° UNIO

Unio terminalis Bourcuicnat, Test. Noviss., 1852, p. 31; Cat.
Rais. Moll. 1853, p. 76, pl. ws, figs. 4-6; Jl. de Conch., IV,
1853, p: 74, pl. 11, figs. 10’ 10”.—Kopentlcon., TV, 1876:
p. 65, pl. cxrx, fig. 115.—SIMPSON, Syn., 1900, p. 689.

Margaron (Unio) terminalis Lra, Syn., 1870, p. 39.

This species is almost evenly long elliptical, being just a
little more rounded on the dorsal than the ventral outline.
The beaks are slightly nearer the anterior end than in the
nearly allied U. pietri and it is not angled at the upper anterior
part. ‘This species has the post-dorsal slope wrinkled and in
pretri there are occasionally traces of folds in this region.
UNIO GRELLOISIANUS Bourguignat.

Shell solid, nearly regularly ovate, inequilateral, inflated or
subinflated ; beaks somewhat full and elevated, their sculpture
consisting of numerous subconcentric ridges that have a ten-
dency to wear into nodules; posterior ridge subangular, placed
near the dorsal line, ending behind in a decided point a little
below the median line: surface finely, concentrically striate ;
epidermis yellowish-fulvous ; pseudocardinals subcompressed ;
laterals slightly curved; anterior muscle scars deep; posterior
scars triangular.

Length 30, height 18, diam. 15 mm.

length 60, height 35, diam. 22 mm.

Jordan River.

Unio grelloisianus Bourcuicnar, Rev. et Mag., VIL, 1856, p.
227, pl. x1, figs. I-4.— SIMPSON, Syn., 1900, p. 689.—KoseELt,
Icon., new ed., XVIII, 1912, p. 58, pl. pvr, fig. 2676.

Unio lunulifer Bourcuicnat, Rev. et Mag., VIII, 1856, p. 227,
pl. xr. figs. 5-8.—Kopetr, Icon., new ed., XVIII, 1912, p.
57, pl. pviti, fig. 2674.

Margaron (Unio) lunulifer Lea, Syn., 1870, p. 37.

Unio jordanicus Bourcutcnat, Rev. et Mag., VII, 1856, p.
228, pl. x, figs. 1-4.—Korew, Icon., new ed., X Vil, 19r2)-p.
56, pl. pvitt, fig. 2672.

Margaron (Unio) jordanicus Lea, Syn., 1870, p. 44-

UNIO 551

The only difference I can see between Bourguignat’s Unio
grelloisianus and his jordanicus is that the former is much
smaller. The figure of the latter in the Magazin shows it to
be nearly 28 mm. in diameter instead of 22 as Bourguignat
states. Both. have the same form, degree of inflation, solidity
and sculpture and very similar teeth, and both are from the
Jordan River.

UNIO ELLIPSOIDEUS Locard.

Shell subelliptical or suboval, rather solid, somewhat inflated,
inequilateral ; beaks elevated above the dorsal line, subinflated,
their sculpture not observed; posterior ridge rounded, ending
behind in a rather blunt point about on the median line; an-
terior end rounded, scarcely if at all angular above; base line
evenly curved; surface with low, concentric ridges; epidermis
brilliant, burnt-yellow, darker or greenish anteriorly, blackish
behind; pseudocardinals ragged, subcompressed; laterals
curved, delicate ; nacre white, rose-color in the cavities.

Length 55, height 32, diam. 23 mm.

Lake Tiberias.

Unio ellipsoideus Locarp, Arch. Mus. Lyon, III, 1883, p. 211,
pl. xx1, figs. 1-3.—Si1MPsoN, Syn., 1g00, p. 690.—KOoBELT,
icon. new ed. oN LET tor, p-.50; pl.pix, fig. 2677:

Unio genezarethanus Locarp, Arch. Mus. Lyon., II, 1883, p.
213, pl. xxi, figs. 4-6—Koser, Icon., new ed., XVIII,
fOi2-p>:50, pl. Dix, fig..2678.

Unio jauberti Locarp, Arch, Mus. Lyon., ILI, 1883, p. 248, pl.
XxIL, figs. 8-to.—Kose.t, Jcon., new ed., XVIII, 1912, p.
54, pl. pvir, figs. 2670, 2671.

Unio sabulonicus Korri/r, Tcon., new ser., VI, 1893, p. 96, pl.
CLE ie, fie: 1120s

Unio lorteti Korner, Icon., rst sup., 1805, p. 14, pl. v, fig.3.

Unio kobelti Roig, Icon., 1st sup., 1895, p. 15, pl. vi, fig. 3.

Unio pietri Korner, (part), Icon., ist sup., 1895, p. 16, pl. vi,
AES) 11:2.

Unio herodes Koper, Icon., tst sup., 1895, p. 17, pl. vi, fig. 4.

552 UNIO

I am very doubtful whether this is more than a mere varia-
tion of U. pietri. It is a little more nearly oval or elliptical
and is nearly or quite destitute of the upper anterior angle.

UNIo DELIcatus Lea.

Shell almost evenly elliptical, convex, inequilateral, sub-
solid, with rather high but not full beaks, their sculpture con-
sisting of irregular, nodulous ridges, which have a tendency
to be doubly looped, the sculpture extending well out on to
the disk in the form of uneven nodules; posterior ridge low,
rounded, ending at the median line in a blunt point; dorsal
line nearly straight ; anterior end a little narrowed and round-
ed; surface with delicate, uneven growth lines; epidermis pale
greenish-yellow, with one or two faint rays on the post-dorsal
slope: teeth delicate, the pseudocardinals compressed; nacre
whitish.

Length 27, height 16, diam. 10 mm.

Orontes River. Syria.

Umo delicatus Lea, Pr. Acad. N. Sci. Phila., VII, 1863, p. 189.
—Jl. Acad. N. Sci. Phila., VI, 1866, p. 58, pl. x1x, fig. 56.—
Obs. XI, 1867, p. 62, pl. x1x, fig. 56—SimMpson, Syn., 1900,
p. 690.—Koset, Icon., new ed., XVIIT, 1912, p. 45, pl. pu,
fig. 2657.

Margaron (Unio) delicatus LEeA, Syn., 1870, p. 42.

This is no doubt a young shell and really ought not to have
been described. It is quite likely that U. ellipsoideus is the
adult of it. Its only decided character is the beak sculpture,
which extends out on to the disk in the form of scattered, ir-
regular nodules or granules.

Group of Unio littoralis.

Shell rather solid, subinflated, rounded rhomboid, with a
faint posterior ridge, usually slightly biangulate behind, and
often becoming arcuate when old; beaks prominent and full;
beak sculpture consisting of numerous rather fine, subparallel
ridges or corrugations, which are sometimes a good deal brok-

UNIO 553

en up, and which extend well out on the disk, but begin at
the beaks as normal, somewhat coarse Unio sculpture, some-
times with fine radial lines posteriorly ; pseudocardinals, rather
solid, subcompressed, smooth below ; laterals straight or slight-
ly curved; cavity of the beaks rather deep; muscle scars dis-
tinct.

I have never seen the soft parts of any member of this
group. Quite a number of descriptions have been published
of various nominal species, most of which go into details as to
the color of the different parts, but do not give an atom of
information as.to real characters. ‘The animal is dark or high-
ly colored, and seems to be gravid in summer, and no doubt
carries the voung in the outer gills alone. Gills large, wider
behind, inner the larger, especially in front; mantle thickened
at the edges ; palpi very large, elliptical, rounded behind, hang-
ing at an angle of 45°; branchial opening large, strongly
fringed.

UNIO LITTORALIS Lamarck.

Shell generally subrhomboid, subsolid to solid, subcompress-
ed to convex, somewhat inequilateral; beaks full and elevated,
their sculpture consisting of numerous broken ridges, which
have often a tendency to become doubly looped. This sculp-
ture quite commonly assumes the appearance of a checkerboard
and extends well out on to the disk; posterior ridge well de-
veloped, single or faintly double, ending behind near the base
of the shell; surface rather rough, the incremental sculpture
irregular, rarely feebly tuberculate; epidermis varying from
dirty yellow-green in the young to black in old shells; in the
lighter colored shells sometimes faintly rayed; left valve with
two pseudocardinals, the anterior compressed, occasionally
joining the triangular posterior one; right valve with one
pseudocardinal, with sometimes a vestigial one in front of and
behind it; sometimes the pseudocardinals are all heavy and
much torn; there are two straight or curved laterals in the

554 UNIO

left valve and one in the right; muscle scars well marked;

beak cavities rather deep; nacre white, flesh-color or salmon-

tinted, thicker in front.
Length &o, height 51, diam. 32 mm.
Length 63, height 46, diam. 26 mm.
Length 61, height 35, diam. 20 mm,
Southern Europe; Asia Minor; Assyria; Morocco; Algiers.

Unio littoralis LAMARCK, Syst. An. sans Vert., 1801, p. 114.—
DRAPARNAUD, Hist. Moll. Fr., 1806, p. 135, pl. x, fig. 20.—
DESHAYES, Enc. Method., II, 1827, p. 151, pl. ccxivim, fig.
2.—ROosSMASSLER, Icon., V, 1837, p. 21, pl. xxiv, fig. 340.— -
Sowersy, Conch. Man., 1839, fig. 145.—Gras, Moil. Isere.,
1840, p. 72, pl. v, fig. 20.—HAN Ey, Biv. Shells, 1843, p. 201,
pl. xx1, fig. 13.—Durvy, Hist. Moll. Fr., 1852, p. 632, pls-
Xxill, fig. 8; xxiv, figs. 5, 6, 8—RossmassiER, Icon., III,
1854, p. 37, pl. LxIx, fig. 850.—Drover, Nay. Fr., II, 1857,
p. 66, pl. 111, figs. 1, 2—RereEve, Conch. Icon., XVI, 1865, pl.
Xx, fig. 98.—-Stmpson, Syn., 1900, p. 691.

Unio littoralis var. mimor ROSSMASSLER (part), Icon., XI, 1842,
Pp. 14, pls Eve bes. 743) 2 Ag.

Unio littoralis var. acarranicus Kone.r, Icon., IV, 1879, p. 40,
pl. CL xia 10 28.

Unio littoralis var. pianensis Kopevyr, Icon., 1V, 1888, p. 43,
pl. cLx11t, fig. 1648.

Margarita (Unio) htoralis Lea, Syn., 1836, p. 32; 1838, p. 22.

Margaron (Unto) litoralis Lea, Syn., 1852, p. 34; 1870, p. 54.

Unio litoralis var. uwmbonatus ROSSMASSLER, Icon., XII, 1844.
Be 27, Di EVI, 1S. 754.

Unio granosus SCHUMACHER, Ess. Nouv. Syst., 1817, pl. 11,
fig. 1.

Unio brevialis LAMARcK, An. sans Vert., VI, 1819, p. 73.

Unio nana I,AMARCK, An. sans Vert., VI, 1819, p. 76.

Unio rubens MENKE, Syn., 1830, p. 149.—RossMASSLER, Icon.,
V and’ Vik 1337p: 56; pl: xxix ieee:

Unio subtetragona Micuaup, Comp. Hist. Moll. Fr., 1831, D-
1a

UNIO 505

Unio subtetragonus Dupuy, Hist. Moll. Fr., 1852, p. 634, pl.
ROM Vin Oe

Unio incurvus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 97, pl.
xi, fig: 27; Obs., 1; 1834, p. 107, pl: x11, fig. 27—CHENU.,
Ill. Conch. 1858, pl. x1, figs. 1, 1a, 1b.

Unio draparnaldi DesHayes, Desc. Coq. Terr., 1831, p. 38, pl.
xvi. fig. 6.

Unio pianensis Farines, Ann des Sci. Nat., II, 1834, p. 118.—
Dupuy,’ Hist. Moll. Fr., 1852, p. 635, pl. xxiv, fig. 4.

Unio bigerrensis Mitier, Guer. Mag., 1843, p. 3, pl. LXVI,
fig. I.

Umi bigorrensis Locarp, Coq. de Franc., 1893, p. 153.

Unio felimani Drsitayrs, Hist. Nat. Moll. Alg., 1848, pl. cviit,
figs. 8, 9.—Kuster, Conch. Cab., 1856, p. 151, pl. xLiv, fig. 1.

Margaron (Unio) fellmani Lia, Syn., 1870, p. 46.

Unio barrandti Dupvy, Hist. Moll. Fr., 1852, p. 635, pl. xxv,
fISeeide:

Unio astierianus Durvuy, Hist. Moll. Fr., 1852, p. 636, pl. Xx111,
fig. 9.—Sowerby, Conch. Icon., XVI, 1868, pl. LXxxv1, fig.
461.

Umio cuneatus RossmMAssiER, Icon., XIII and XIV, 1854, p.
27, Dl LXIX, tie, S5r.

Unio rhomboideus Mooutn-Tanpon, Moll. Terr. Fluvy. Fr..
II, 1855, p. 568, pl. xivim, figs. 4, 9; xLIx, figs. 1, 2—Bour-
GUIGNAT, Mal. Alg., 1864, II, p. 284, pl. xvit1—Locarp,
Caqide Pranc., 1893. p. 152, fig 165.

Unio rothi Bourcurcnat, Moll. Nouv., 1863, p. 41, pl. xx, figs.
1-6; Rev. et Mag., XVII, 1865. p. 337, pl. xv1.—KoseE tt,
lean., V1; 1879, p.-40;, pl. CLXI,. ig. 1630.

Unio umbonatus BourcutcNnat, Moll. Nouv., 1863, p. 42, pls.
xx, XVil; Rey. ct Mag., X VII, 1665, p. 330, pls: xvii, XVIII.

Unio subreniformis Bourcuicnat, Moll. Nouv., 1863, p. 43.—
Kosey.t, [con., [V, 1876, p. 64, pl. cxvii, fig. 1151.

Unio ater Reeve, Conch. Icon., XVI, 1865, pl. xx1, fig. 109.

Unio crassus Reve, Conch. Icon., XVI, 1865, pl. xx11, fig. 98.

Unio valentinus Sowrersy, Conch. Icon., XVI, 1866, pl. X11,
fig. 225.

556 UNIO

Unio mauritanicus Bourcuicnat, Moll. Nouv., 1868, p. 317,
pl. xiv, figs. 1-5.—Kosext, Icon., I, new ser., 1886, p. 5,
pl. xxxiu, fig. 230.

Umio ksibianus Mousson, Mal. Blatt., XXI, 1873, p. 156;
Jahrb. Deuts. Mal. Ges., I, 1874, p. 104, pl. v, fig. 6—Ko-
BEWT Jicon,, 1V,,new ser.;.1870,. p65, pls cxixernosemnse!

Umio jolyi Kove t, Icon., new ser., II, 1886, p. 22, pl. x1, fig.
250. :

Unio maccarthyanus Koper, Icon., new ser., II, 1886, p. 5,
DISK aie 226)

Unio letourneaurt Koper, Icon., new ser., II, 1886, p. 3, pl.
KOKI eae

Unio -lycicus RovuLE, Lcon., 1stistip.;.1895, p16, pl ie, me.
Considering the abundance of specimens of this species and

its wide distribution, I do not think it a remarkably variable
form. It is usually decidedly rhomboid, is subcompressed or
convex but rarely subinflated. The lighter colored specimens,
which are generally young, quite commonly show rays and
there is sometimes a broad ray that covers the whole posterior
end. The checker board pattern of beak sculpture is charac-
teristic, sometimes spreading well out on the disk. I have seen
no forms that seem to be worthy of varietal rank.

Lamarck refers this in the Animaux sans Vertebres first to
his Systeme An. sans Vert., published in 1801, and thirdly to
Draparnaud (Hist. Moll. Fr., 1806). Draparnaud published
this species under the name Unio littoralis without a figure in
the Tableau Mollusques de France, 1801, which appeared, ac-
cording to Moquin-Tandon, about July 1 of that year. I do
not know: which has priority, but Lamarck refers to a charac-
teristic figure in the Encyclopedia Methodique (1797), thus
fixing the species without a doubt, and as he is most generally
considered its author I shall credit it to him.

Hannibal, (Proc. Mal.-Soc. London; xX, 1912;*p.124)), ads
made this species the type of a new genus, Migranajas, based
on the characters of the beak sculpture and the hinge-teeth.

UNIO

n
on
~J

UNIO DELESSERTI Bourguignat.

Shell subrhomboid, rather short, inequilateral, subcompress-
ed, apparently subsolid ; beaks elevated a little above the dorsal
line but not full, their surface rugose; posterior ridge widely
double, ending behind near the base of the shell in a wide
biangulation ; surface densely, concentrically striated; epider-
mis yellow, faintly rayed with brown; pseudocardinals sub-
compressed, ragged; laterals nearly straight, lamellar; nacre
reddish.

Length 49, height 32, diam. 17 mm.

Syria.

Umio delessertt Bourcuicnat,, Voy. Mer. Mort., 1852, p. 77;
Cat. Rais. Moll., 1853, p. 77, pl. 1, figs. 7-9—SImMPsoN,
Syn., 1900, p. 692.—KoseExT, Icon., new ed., XIX, 1912, p.
33, pl. DXXvII, fig. 2728.

Margaron (Unio) delesserti Lea, Syn., 1870, p. 46.
Extremely close to U. duriew apparently and probably only

a variety of it. It is higher in proportion to the length than

any specimens | have seen of that shell; it is more widely and

distinctly biangulate behind and the nacre is reddish, a tint

1 have never seen in that species. .

UNIO SEMIRUGATUS Lamarck.

Shell short, subrhomboid, convex to subintlated, somewhat
inequilateral, solid; beaks full and high, their sculpture con-
sisting of broken ridges often arranged in checker board pat-
tern; sometimes they are slightly chevron-shaped or zigzag-
ged; posterior ridge faint, rounded or rarely biangulate; sur-
face usually rudely. and unevenly sculptured by the growth
lines; epidermis ashy, pale olive or yellowish-green and often
rayed in the young, becoming dark brown in the old shells;
left valve with two pseudocardinals, the anterior compressed,
often joining the more solid posterior one, and two curved
laterals; right valve with one pseudocardinal, with vestiges
of one in front, and another behind and one lateral; beak cav-
ities rather deep ; muscle scars impressed ; nacre whitish, some-

558 UNIO

times tinted flesh-color or purplish, dirty, a little thicker in

front.

Length 55, height 38, diam. 24 mm.
Length 43, height 33, diam. 19 mm.
Asia Minor.

Unio semirugatus LAMARCK, An. san. Vert., VI. 1819, p. 76.—
DELESSERT, Rec. Cog. Lam., 1841, pl. x1, figs. 6, 6a, 6b.—
SIMPSON, Syn., 1900, p. 693.

Unio emesaensis Lea, Pr. Acad. N. Sci. Phila., VIII, p. 286;
Jl. Acad. N. Sci. Phila:, VI, 1868, p. 254, pl: xxx) dig. 68
Obs., XII, 1860, p. 14, pl. xxx, fig. 68—KoseEt, Icon., new
ed;, XVIII; 19125 p: 51, pl.pve he. 2066:

Margaron (Unio) emesaensis L&A, Syn., 1870, p. 57.

Unio simonis 'TRistRAM, Pr. Zool. Soc. Lond., 1865, Pt. 2, p.
544.—Locarp, Arch. Mus. Lyon, II], 1883, p. 239, pl. xx,
figs. 1-3.—KopeLt, Icon., new ser., VI, 1893, p. QI, pl-
CLXXVL, figs T1213 first supp., 1605, p; 18, pla 1m, cess
new-ed:, XTX P1912; pa18, pl pk xahe. 2768:

Unio luynesi Locarp, Arch. Mus. Lyon, III, 1883, p. 205.

Unio galilei Locarp, Arch. Mus. Lyon, III, 1883, p. 206, pl.
Xx, figs. 10-12. KoseEtt, Icon., Ist. sup., 1895, p. 20, pl. vi,
figs. 4, 5.

Unio timius Locarp, Arch. Mus. Lyon, III, 1883, p. 207, pl.
Xx, ofigs: 13, 14; Moll. aes Tiberiade, p- 207, pl. sexs iss:
13, 14.—Koeez tt, Icon., new ed., XIX, 1912, p. 20, pl. DxxIVv,
ee 2723.

Unio rhomboidopsis Locarp, Arch. Mus. Lyon, III, 1883, p.
220 api kX, 12S.7-0:

Unio rollei Kozet, Icon., Ist. supp., 1895, p. 20, pl. Iv, figs. 1,

a

2

Unio trache@ Koper, Icon., ist. supp., 1895, p. 21, pl. vila,
fig. 2.

Unio wagnert Kose, Icon., Ist. supp., 1895, p. 22, pl. vu,
figs sins

Unio (Rhombunio) abrus Kose, Icon., new ed., XIX, 1912,
p. 10, pl. pxvt, fig. 2606.

UNIO 559

Unio (Rhombunio) halepensis Koper, Icon., new ed., XIX,

1912, p. 20, pl. Dxx1I, figs. 2709-2711.

Unio corbiculiformis Koseit, Icon., new ed., XIX, 1912, p.

227 pi, DIT, 119, 27 12.

Unio (Rhombunio) babensis Korey, Icon., new ed., XIX,

{Ol2, cp. 22, ply DEXI, fie. 2713.

Unio graeteri Kope.t, Icon., new ed., XIX, 1912, p. 23, pl.

DXXII, fig. 2714.

Unio (Khombunio) emesaensis Kovexr, Icon., new ed., XIX,

1912, p. 24, pl. DxxI1I, figs. 2715, 2716.

Unio (Rhombuno) rhomboidopsis \osELT, Icon., new ed.,

MOEX, 1012, p: 25,- pl. DxXxi, fig. 2717.

Unio (Rhombunio) naegelet Koseir, Icon., new ed., XIX,

TQM a ee255 ple DMT, 1S. 2718.

Unio blanchianus Koper vt, Icon., new ed., XIX, 1912, p. 27,

pl. Dxx1v, figs. 2719, 2720.

Unio beroeus Kosei’, Icon., new ed., XIX, 1912, p. 29, pl.

DXKIV, fies 2722.

This form seems to replace U. littoralis in Asia Minor. It
is generally smaller than that species, less rhomboid and more
inflated. Some specimens are almost suborbicular, though
they preserve the tendency towards being rhomboid; others
are almost as rhomboid as littoralis, but are, as a rule, shorter.
Locard’s figure of U. simonis in the Archives shows a slightly
larger form than I have seen, and it is decidedly rhomboid.
He may have known the reason for separating U. rhomboid-
opsis from this species, but I do not.

For this species, U. rothi Bgt., and U. homsensis Lea Ger-
main, (Bull. Mus. Hist. Nat.. 1911, p. 67), has recently pro-
posed a new subgenus, Rhombunio, but without specifying the
characters upon which it is based.

UNIO HOMSENSIS Lea.

Shell long rhomboid, subcompressed, solid, inequilateral ;
beaks somewhat elevated but not full, their sculpture not ob-
served; posterior ridge full, widely rounded, ending behind
near the base of the shell; dorsal line curved but ending in an
angle behind at the oblique truncation of the posterior slope ;

560 UNIO

surface with moderate growth lines, covered with a thick,

rather rough, dark brown or blackish, epidermis, which is

inclined to peel off; left valve with two small stumpy, nearly
smooth pseudocardinals and two low, club-shaped laterals, the
upper small; right valve with one stumpy pseudocardinal and

a vestigial one behind it, with a single club-shaped lateral ;

hinge plate rather wide; beak cavities deep, compressed ; mus-

cle scars deep, the anterior roughened; nacre rich purple,
thickened in front.

Length 96, height 56, diam. 33 mm.

Length 70, height 41, diam, 24 mm.

Syria.

Unio homsensis Les, Proc. Nat. Sei. Phila., VIII, 1864, p. 285 ;
Jl. Acad. Nat. ‘Sei. Phila, VI, 1868, p: 240, ‘pl. xxix; fie:
63; Obs. XII, 18609, p. 9, pl. xxix, fig. 63—SIMPSON, Syn.,
1900, p. 693.—Kosxrr,1, Icon., new ed., XVIII, 1912, p. 53,
pl. pvi, fig. 2669. ~

Margaron (Unio) homsensis Lava, Syn., 1870, p. 31.

Two opposed valves of this species are all the material I
have seen. In the smaller of these the posterior slope is slightly
corrugated. It is more elongated than U. littoralis, and the
nacre is a rich purple.

Unio PSEUDONYMUS Simpson.

Shell irregularly subrhomboid, much inflated, solid, inequi-
lateral; beaks high and full, with peculiar tuberculated sculp-
ture; posterior ridge not well developed, rounded; posterior
end subtruncated ; anterior end cut away slightly below; dorsal
and basal lines rounded; surface apparently having rather
strong concentric sculpture, greenish-yellow, darker behind
with a few narrow rays on the posterior half of the shell;
ligament large; pseudocardinals solid, crenate; laterals elon-
gated; muscular impressions distinct; nacre white, iridescent.

Length 75, height 42, diam. 34 mm.

Euphrates and Tigris rivers.

Unio hueti Korner, Icon., new ser., II, 1886, p. 22, pl. x1, fig.
22

Unio pseudonymus Stmpson, Syn., 1900, p. 694.

UNIO 561

Kobelt supposed this to be the Unio hueti of Bourguignat
and figured and described it for that species. It is however,
quite distinct from that and is apparently undescribed. It is
greatly inflated, more so than any member of the group that
I am acquainted with, is solid, and apparently has strong,
concentric sculpture. It is rather remarkable in having the
front half rayed and the hinder half rayless.

UNIO FERUSSACIANUS Lea.

Shell irregularly subelliptical or subtrapezoid, subsolid, cou-
vex, somewhat inequilateral; beaks somewhat elevated and
full, pointed, sculptured with a large number of corrugated,
more or less broken, ridges, which show a tendency to be
doubly looped, the sculpture extending well out on to the disk ;
posterior ridge scarcely developed; dorsal line arched, ending
behind in a feeble angle at the subtruncation of the posterior
slope; base line nearly straight; anterior end evenly rounded
and a little narrowed; surface finely concentrically striate,
greenish-yellow, feebly rayed behind and showing dark brown
rest periods: left valve with two high, compressed, sharp pseu-
docardinals and two straight laterals; left valve with a high,
compressed lower pseudocardinal and a faint upper one with
one somewhat double lateral; beak cavities moderately deep;
nacre bluish-white, scarcely thicker above.

Length 48, height 31, diam. 19 mm.

Bagdad.

Unio ferussacianus Lea, Jl. Acad. Nat. Sci. Phila., VI, 1868,
p- 255. Footnote to description of U. emesaensis—L*A,
Obs. XII, 1869, p. 15. Footnote——Simpson, Syn., 1900, p.
604.

Margaron (Unio) ferussacianus Lea, Syn., 1870, p. 46.

This may be only a variety of U. durieui, but it is shorter,
solider and a little more inflated than that species. The great-
est inflation is at the middle of the shell and from this point
it is wedge-shaped in front and behind while duriew is almost
evenly convex.

562 UNLO

UNIO EPISCOPALIS Tristram.

Shell rather large, elongated, subquadrate, solid, subcom-
pressed, somewhat inequilateral ; beaks high but not very full,
apparently sculptured with undulating plications; posterior
ridge widely rounded, ending behind near the base; posterior
end with a slightly oblique truncation above, rounded below ;
base line straight or a little incurved in the middle; surface de-
cidedly concentrically sculptured; epidermis black; pseudo-
cardinals high, thick, subacute; laterals strong, elongated ;
nacre brillant purple: pallial sinus deep ; anterior muscle scars
deep; posterior scars well marked.

Length 90-100, height 50-60, diam. 30-35 mm.

Orontes and Jeontes rivers, Syria.

Unio episcopalis TRistRAM, Pr. Zool. Soc. Lond., 1865, p. 544.
—Koeet, Icon., VI, new ser., 1893, p. 89, pl. cLxxv, fig:
LLI9.—SIMPSON, Syn., 1900, p. 694.

Tristram calls this the prince of Oriental Unionide. It
appears to be close to U. homsensis, but is much more squarely

truncate behind and is more rounded at the post-basal termina-
tion.

Unio purreut Deshayes.

Shell oblong, subrhomboid, rarely almost elliptical, having
the dorsal and basal lines nearly parallel, inequilateral, convex,
subsolid ; beaks only moderately full and elevated, their sculp-
ture consisting of numerous broken, fine, corrugated ridges,
which are sometimes more or less doubly looped and often
arranged in imperfect zigzag patterns. This sculpture extends
well out on to the disk, gradually changing to subnodulous con-
centric ridges and lower down into delicate but well-marked
growth lines that are strongest on anterior end of the shell.
Posterior ridge low, sometimes feebly double and ending at
end below the median line in an ill-defined biangulation ; epi-
dermis yellowish or ashy-green to smoky-brown, often feebly
raved: left valve with two sub-compressed, ragged pseudo-
cardinals and two nearly straight laterals; right valve with one

UNIO 563

pseudocardinal, often with a vestigial one above it and one
lateral ; beak cavities not deep; nacre whitish, often somewhat
silvery, a little thickened in front.
Length 63, height 35, diam. 21 mm.
Length 55, height 28, diam. 19 mm.
Length 51, height 31, diam. 19 mm.
Algiers ; Tunis; Asia Minor; Assyria; Southeastern Europe.

Unio duriewi Desuayes, Hist. Nat. Moll. Alg. Atlas, 1847, pl.
cIx, figs. 5-8.—Bourcuicnat, Moll. Alg., II, 1864, p. 288, pl.
xIx, figs. 4-8.—SIMPSON, Syn., 1900, p. 694.

Margaron (Umo) durieui L&a, Syn., 1852, p. 39; 1870, p. 48.

Unio sitifensis Morevet, Jl. de Conch., II, 1851, p. 360.

Unio orientalis Pourcuicnat, Test. Noviss., 1852, p. 209.

Unio brugwierianus BouRcuIGNAT, Cat. Rais., 1853, p. 78, pl. |
ul, figs. 54-58.—Kopbe rt, Icon., new ed., XIX, 1912, p. 39,
plpx yx, tie 127 37.

Margaron (Unio) brugmerianus Lea, Syn., 1870, p. 44.

Unio vescoi Bourcuicnat, Rev. et. Mag., VIII, 1856, p. 74,
pl. 11, figs. 4-8—Kopsett, Icon., [V, 1876, p. 66, pl. cxrx, fig.
1154.°

ne (Unio) vescot Lea, Syn., 1870, p. 46.

Unio schwerzenbacht Bourcuicnat, Rev. et Mag., VIII, 1856,
p- 75, pl. vin, figs. 1-5.—Kuster, Conch. Cab. Unio, 1862,
p. 266, pl. xc, fig. 2—Sowrrsy, Conch. Icon., XVI, 1868,
pl. xiv, fig. 241.—Kosevt, Icon., VII, 1880, p. 81, pl. ccv1,
fig. 2099.

Unio prusi Bourcuicnat, Rev. et Mag., VIII, 1856, p. 76, pl.
11, figs. I-4.

Unio damascensis Lua, Pr. Acad. Nat. Sci. Phila., VII, 1863,
p. 190; Jl. Acad. Nat. Sci. Phila., VI, 1866, p. 55, pl. xvi11,
fig. 52; Obs. XI, 1869, p. 59, pl. xvi, fig. 52.—KoseE-r,
Icon., new ed., XVIII, 1912, p. 45, pl. p11, fig. 2656.

Margaron (Unio) damascensis Lea, Syn., 1870, p. 52.

Unio orontesensis Les, Pr. Acad. Nat. Sci. Phila., VII, 1863,
p. 190; Jl.-Acad: Nat. Sci. Phila, VI, 1866, p. 53, pl. xvu1,
fig. 50; Obs. XI, p. 57, pl. xvi, fig. 50.—Koser‘, Icon.,
new ed., XVIII, 1912, p. 45, pl. piu, fig. 2650.

Margaron (Unio) orontesensis Lea, Syn., 1870, p. 52.

564 UNIO

Unio orphaensis Lea, Pr. Acad. Nat. Sci. Phila.; VII, 1864,
p. 285; Jl. Acad. Nat. Sci. Phila, Wi. 1868, p. 250, pl xox.
fig. 64; Obs. XII, 1869, p. 10, pl. xx1x, fig. 64—KoBEI,7,
Icon., new ed., XVIII. 1912, p..52; plo pvt, figs: 2067, 2603:

Margaron (Unio) orphaensis Lea, Syn., 1870, p. 52.

Unio orfaensis Kose, Icon., new ed., XIX, 1912, p. 37, pl.
DXXX, figs. 2734, 2735.

Unio (orfaensis var.?) ehrmanni Koper, Icon., new ed., XIX,
1912, p. 38, pl. Dxxx, fig. 2736.

Unio mardinensis LEA, Pr. Acad. Nat. Sci. Phila., VIII, 1864,
p.-286; Jl. Acad. Nat. Sei. Phila. : Vij 1868". 252) pl sexe
fig. 66; Obs. XII, 1860, p. 12, pl. xxx, fig. 66.—KOoBELT,
Icon., new ed., XVIII, 1912, p. 49, pl. pv, figs. 2663, 2664.
Deshayes’ shell is a young specimen, which is straight on

the base, but this figure agrees essentially with the shells of a
considerable number of so-called species on the south shore
and around the eastern-end of the Mediterranean. ‘There is
some variation in dimensions and color but all agree well in
the generally long, subrhomboid form, the sculpture, which is
stronger anteriorly, the much broken and wide-spread beak
sculpture, the teeth and the nacre.

Var. kullethensis Lea.

A little solider and more inflated than the typical U. durieut.
The anterior end is greenish-yellow; the posterior end is cov-
ered with almost coalescing green rays.

Length 53, height 30, diam. 20 mm.

Near Mardin in a tributary of the Tigris River.

Unio kullethensis Lea, Pr. Acad. Nat. Sci. Phila., VIII, 1864,
p. 285; jlsAcad. Nat. Sci..Phila WV i 1868) p25. ples
fig. 65; Obs. XII, 18609, p. 11, pl. xxx, fig. 65.—KoBE rT,
Icon., new ed., XVIII, 1912, p. 50, pl. pv, fig. 2665.

Margaron (Unio) kullethensis Lea, Syn., 1870, p. 53.

Unio kallethensis and kullinthensis Pavret, Conch. Sam., III,
T890, p. 156.

Unio durieui var. kullethensis, Stwpson, Syn., 1900, p. 695.

UNI 565

Unio syriacus Lea.

Shell small, subrhomboid, inflated, subsolid, inequilateral ;
beaks slightly elevated above the dorsal line, not inflated, their
sculpture not seen; posterior ridge very full, rounded; dorsal
line slightly curved; basal line straight; anterior end rounded ;
posterior end obliquely subtruncated above, rather widely
rounded below; surface with rather strong growth lines; epi-
dermis yellowish-ashy, rather smooth; left valve with two
small, subcompresséd pseudocardinals and two laterals, the
lower the larger: right valve with two pseudocardinals, the up-
per very small, and one lateral; nacre pale dirty salmon, rather
soft and silvery, a little thicker in front; muscle scars small,
well impressed.

Length 34, height 22, diam. 17 mm.

Orontes River, Syria.

Unio syrtacus Lea, Pr. Acad. Nat. Sci. Phila., VII, 1863, p.
189; Jl. Acad. Nat. Sci. Phila, VI; 1866,-p. 56, pl. xxx, fig.
53; Obs., XI, 1867, p. 60, pl. xrx, fig. 53 Simpson, Syn.,
1900, p. 695.—Kosevt, Icon., new ed., XVIII, 1912, p. 44.
pl. pir, fig. 2655.

Margaron (Unio) syriacus Lea, Syn., 1870, p. 35.

A miserable little specimen with the umbonal and post-dor-
sal regions entirely eroded away, the type, is the only specimen
I have seen. This is decidedly inflated, the greatest swelling
being along the line of the very full posterior ridge, and from
this it is wedge-shaped in front and behind.

Unio pyTHINicus Kobelt.

Shell long rhomboid. the dorsal and ventral lines nearly
parallel, the anterior end rounded, the posterior subtruncate
above, subcompressed. inequilateral, subsolid; beaks eroded
badly in the specimen figured but not raised above the dorsal
line and compressed; posterior ridge rounded and ending in
a rounded point near the base of the shell; surface concentri-
cally striate, unicolored, brownish-green ; hinge rather delicate :

566 - UNIO

pseudocardinals compressed; laterals slightly curved; nacre
bluish-white tinted with salmon, iridescent behind.

Length 57, height 27, diam. 17 mm.

Asia Minor.
Unio bythinicus Koper, Icon., new ser., VI, 1893, p. 96, pl

CLXXIX, fig. 1128.—Simpson, Syn., 1900, p. 695.

This may group with U. pictorum. It is an elongated rhom-
boid, compressed and unicolored species with no very striking
characters.

UNIO MICELII Kobelt.

Shell oblong, subinflated, solid, inequilateral, with very high,
rounded and rather full beaks, their sculpture not observed ;
posterior ridge well developed, rounded, extending towards
the posterior base where the shell is widely rounded, above
this it is obliquely truncated behind; dorsal line meeting this
truncation with an angle; base line lightly incurved; surface
strongly concentrically sulcate; epidermis brownish or black-
ish-olivaceous ; pseudocardinals heavy ; laterals low but solid;
anterior muscle scars large and deep; posterior scars super-
ficial; pallial lines strongly crenate; nacre rose-tinted.

Length 92, height 45, diam. 32 mm.

Tunis.

Unio micelu Konevt, Nach. Mal. Ges., XVI, 1884, p. 182;
Icon:, new ser., II, 1886, p. 24, pl. x1im, figs. 260, 261.—
SIMPSON, Syn., 1900, p. 695.

This seems to be a very distinct species, being quite ponder-
ous and having high, widely rounded beaks. The surface is
rudely, concentrically sculptured and is a dark brown or black-
ish-olivaceous color without rays.

UNIO EMARGINATUS Lea.

Shell oblong, slightly arcuate, subrhomboid, subsolid, inequi-
lateral, subcompressed ; beaks slightly elevated above the dor-
sal outline, scarcely inflated, their sculpture apparently a num-
ber of broken corrugations that are inclined to be doubly
looped; posterior ridge high, rounded above, somewhat dou-

UNIO 5607

ble below, ending behind at the median line and base in a wide,
feeble biangulation; dorsal line irregularly curved; dorsal
slope obliquely truncated ; base line incurved; surface irregu-
larly, concentrically sculptured; epidermis dirty greenish-yel-
low, the posterior part green; right valve with one sub-com-
pressed pseudocardinal with a vestige of another above it and
one granular lateral; muscle scars shallow; beak cavity not
deep; nacre bluish-white, silvery, iridescent behind, thickened
in front.

Length 73, height 33, diam. 22 mm.

Locality unknown. I have no doubt that it belongs some-
where in the circummediterranean region.

Unio emarginatus Lea, Tr. Am. Phila. Soc., V, 1834, p. 62, pl.
IX, fig. 22; Obs., I, 1834, p. 174, pl. 1x, fig. 22—SimpPson,
Syn., 1900, p. 695.

Margarita (Unio) emarginatus Lea, Syn., 1838, p. 26.

Margaron (Unio) emarginatus Lea, Syn., 1852, p. 39; 18760,
p. 62.

Lea’s only shell, the type, consists of two opposite, odd
valves. One of these may possibly be an elongated batavus, the
other appears distinct. This right valve is irregularly and
rather strongly concentrically sculptured, it is decidedly arcu-
ate; the front part of the shell is a dirty greenish-yellow while
all that part behind the lower angle of the posterior ridge is
dirty green. The beak is so eroded that the sculpture is not at
all distinct, but it seems to have the character of members of
the littoralis group.

UNIO CARNEUS Kuster.

Shell subrhomboid or subtrapezoidal, subcompressed to con-
vex, subsolid or rather thin, quite inequilateral; beaks only
lightly raised above the dorsal line, not inflated, their sculp-
ture consisting of numerous, wavy, somewhat broken ridges;
posterior ridge generally double, the upper angle ending be-
hind on the median line, the lower reaching to about the base
of the shell; dorsal line slightly curved, meeting the oblique
truncation of the dorsal slope with an angle; posterior end

568 UNIO

almost squarely truncated; base line nearly straight; anterior
end narrowed and rounded; surface with strong, uneven
incremental striz; epidermis ashy-green, ashy or reddish-
brown, dull; pseudocardinals compressed; laterals delicate ;
beak cavities not deep; muscle scars shallow; nacre flesh-col-
ored, sometimes blue-tinted, a little thicker in front.

Length 56, height 30, diam. 18 mm.

Southern Europe.

Unio carneus Kuster, Conch. Cab. Unio, 1854, p. 103, pl.
XXVIII, figs. 1, 2—SimMpson, Syn., 1900, p. 696.

Unio gontierti BourcuIGNAT, Rev. et Mag., IX, 1857, p. 16, pl.
Iv, figs. 1-4.

Margaron (Unio) gontieri Lea, Syn., 1870, p. 44.

Unio penchinatianus Bourcuicnat, Moll. Peu. Con., 1863, p.
A4, pl: xxv. Rev. et Mac. XS 1865p, 342, pean —
Koper, leon: 1V, 1876,-p. 66, pl: cx nev rrss.

Close to forms of U. batavus and bearing about the same
relation to it that elongatulus does to pictorum. It is less in-
flated, is thinner and rougher than batavus and is more decid-
edly widened and biangulate behind.

Unio BAtavus (Maton and Rackett).

Shell long elliptical, subrhomboid or when old slightly arcu-
ate. subsolid to solid, convex to subinflated, inequilateral ;
beaks slightly elevated above the dorsal line and but moderate-
ly inflated, sculptured with numerous rather fine, corrugated,
broken ridges; sometimes these ridges are somewhat doubly
looped and subnodulous; posterior ridge low and rounded;
surface with fine or uneven incremental lines, sometimes nearly
smooth ; epidermis vellowish-green or greenish-vellow, tawny.
olive, brownish or almost black, often rayed, especially in the
lighter colored examples; left valve with two small, subcom-
pressed or stumpy pseudocardinals and two straight or faintly
curved laterals; right valve generally having two pseudo-
cardinals, the upper small, sometimes wanting, and one lat-
eral; beak cavities not deep; muscle scars rounded, the anterior

UNIO 569

impressed; posterior scars superficial; nacre bluish-white,

white or flesh-tinted, a little iridescent behind, thickened in

front.
Length 76, height 36, diam. 29 mm.
Length 7o, height 38, diam. 24 mm.
Length 58, height 30, diam. 20 mm.
Europe; Asia Minor; Northwest Africa.

?Mya pictorum GMELIN, Syst. Nat., 13th ed., 1788, p. 3218.—
Donovan, Brit. Shells, V, 1803, pl. cLxxiv.—?CHENU, Bib.
Conch., 1st. ser., I, 1845, p. 114, pl. xLvit, figs. 8, 9.

Umo pictorum DRAPARNAUD, part, Hist. Moll. Fr., 1806, p. 131.
pl. x1, figs. 1-4.

?Unmio musivus SPENGLER, Skriv. Selsk., III, 1793, p. 67.—
Haas, Beil. z. Nachtr. D. Mal. Ges., No. 4, p. 62.

Unio crassus musivus ORTMANN, Ann. Car. Mus., VIII, 1912,
Pp. 275. ;

Unio musicus SIMPSON, Syn., 1900, p. 744.

Mya batava Maton and Racuevt, Tr. Linn. Soc. Lond., VIII,
1807, p. 37-—Woop, Gen. Conch., I, 1815, p. 303, pl. x1x,
Aen Aa end lest. 18255) p.: 12; -pl. 11, fie: 25D) meve-ed.,
POGOs asloe Dis tty fos es.

Unio batava LAMARCK, An. sans Vert., VI, 1819, p. 78.—C.
PFEIFFER, Nat. L. and Suss. Moll., Pt. 1, 1821, p.. 119, pl:
v, fig. 14—DesHaAyes, Enc. Meth., II, 1827, p. .151, pl.
Sexi to LTS sO.8p. So4.cpi CCXLVILI, fig: 3.

Mysca batava Turron, Man. L. and F. W. Shells, Brit. Is.,
Las bep. Ks TO.

Unio batavus Nitsson, Hist. Moll. Svec., 1822, p. 112.—Ross-
MASSLER, Icon., II, 1835, p. 20, pl. vit, figs. 128, 128a, 128);
Ti, 1536, pp. 28, 32; pl. xiv. He. 205); xv, fir. 214; V and
Wi e1837.7p, 50,upl. xxi ps 4a; XI, 1842, p. 14; pl. tv,
fig. 745.—Brown, L. and F. W. Conch., 1836, p. 111, pls.
XV, figs. 6-8; xxt, figs. 10, 11; Ill. Recent Conch., 1844, p.
82, pl. xxxt, figs. 3, 3a, 4-6.—Dupuy, Hist. Moll. Fr., 1852,
p. 638, pl. xxv, figs. 14, 15.—Kustrer, Conch. Cab. Unio,
1854, p. 121, pl. xxxi1t, figs. 4-7; XXXIV, figs. 1,2——MoguIn-
TANpon, Moll. Terr. et Fluv. Fr., IJ, 1855; Pp. S71, plisehs

570 UNIO

figs. 7, 8.—Drovet, Nay. Fr., I, 1857, p. 79, pl. vi, fig. 1.—

30URGUIGNAT, Mal. Alg., 1864, p. 286, pls. x1x, fig. 9; xx,
figs. I1-4.—Sowerby, Conch. Icon., XVI, 1866, pl. xii, fig.
234.—Brot, Coq. Fam. Nay. Leman, 1867, p. 49, pl. 1x, figs.
1-5.—Ciessin, Deutsche Ex. Moll., 1876, 463, fig. 302.—
SIMPSON, Syn., 1900, p. 696.

Margarita (Unio) batavus LEA, Syn., 1836, p. 26; 1838, p. 20.

Margaron (Unio) batavus Lea, Syn., 1852, p. 30; 1870, p. 47.

Unio batavi var. ? RossMASSLER, Icon., V and VI, 1837, p. 55,
pla xix ties ATO:

Unio riparia C. PFEIFFER, Nat. L. and $. Moll., 1821, pt. 1, p.
11, .pleV, Ho. 13.

Unio riparius ScHowz, Schleis L. and W. Moll., 1843, p. 129.

Unio crassus Nitsson, Hist. Moll. Svec., 1882, p. 108.—Ross-
MASSLER, Icon., [I, 1835, p. 19, pl. vri1, figs. 126, 127; V and
VI, 1837, p. 55, XXXIX, fig. 411.—Mogui1n-Tanpon, Moll.
Terr. and Fluy. Frc; lh 1855, \p: 570 alls pr sare shies oe
—NoORDENSKIOLD and NyLANpkgR, Fin. Moll., 1856, p. 84, pl.
vi, fig. 72.—Drovuet, Nay. Fr., I, 1857, p. 76, pl. iv, fig. 2.
—lLocarp, Coq. de Fr., 1893, p. 162, fig. 176.—ORTMANN,
Ann. Cara Minise Vell. Ione. 275-

Unio crassus variety batavus JORDAN, Jahrb. Deuts. Mal. Ges.,
Vij 18705p-4307.

Unio ater Nitsson, Hist. Moll. Svec., 1822, p. 107.—Ross-
MASSELBRY Icon: IL) 18350 p4295 pl mx, foe 133. Vlleand
VIII, 1838, p. 41, pl. xu, fig. 543.—Kuster, Conch. Cab.
Unio, 1854, p. 114, pls. xx, figs. 1, 2, 6; xxxt1, figs. 1-4.—
Moguin-Tanpon, Moll. Terr. et Fleuv. Fr., I], 1855, p. 570,
pl. xix, figs. 5. 6—Drouer, Nay. Fr, 11, 1857, p. 72, pl
TVs tion a

Unio atra DrsHayes, Encyc. Meth., II, 1830, p. 582.

Unio rugatus MENKr, Syn. Moll., 1828, p. 90.—ROSSMASSLER,
Teon.s V and V1, 1837, p: 65, pl xmas fie 240s:

Unio elongata Micnaup, Comp. Hist. Moll. Fr., 1831, p. 113,
ple Xvi, Teo;

Unio labacensis RossMAsstER, Icon., IT, 1835, p. 21.

UNIO 571

Unio decurvatus RossMaAss.Er, Icon., II, 1835, p. 22, pls. 1x,
fis. 131; V and VI, 1837, p. 21, pl. xxiv, fig. 339.—KustTer,
Conch. Cab. Unio, 1856, p. 108, pl. xxx, figs. 1, 2—Mus-
GRAVE, Phot. Conch., 1863, pl. 1, fig. 4.—Sowersby, Conch.
Icon., XVI, 1867, pl. Lv1, fig. 284.

Unio reniformis RossmMAss.eR, Icon., III, 1836, p. 31, pl. xv,
fig. 213.—KustTER, Conch. Cab. Unio, 1854, p. 110, pl. xxx,
figs. 3, 4.—Bourcuicnat, Rev. et Mag., 1865, pl. xxim1, figs.
4-6— Sowersy, Conch. Icon., XVI, 1868, pl. Lxxu, fig. 371.

Unio carinthiacus RossMAssieR, Icon., II, 1836, p. 30, pl. xv,
fig. 209.—Sowerrsy, Conch. Icon., XVI, 1856, pl. xxx, fig.
Roy

Unio amnicus RossMAsSLER, Icon., II, 1836, p. 31, pl. xv, fig.
212.—Kuster, Conch. Cab. Unio, 1856, p. 99, pl. xxvu, fig.
2.—LocaARD, Cog. de Fr., 1893, p. 163, fig. 177.

Unio piscinalis ROSSMASSLER, Icon., III, 1836, p. 30, pl. xv, fig.
210.

Unio atrovirens ROSSMASSLER, Icon., IIT, 1836, p. 28, pl. xv,
figs. 206, 207.

Unio consentaneus ROSSMASSLER, Icon., III, 1836, p. 29, pl. xv,
his. 208; VIL, #838, p. 25, pl. xxxv, fig. 491; p. 42, pl. xt, fig.
544; XI, 1842, p. 14, pl. Lv, fig. 742.

Unio fusculus RossMASSLER, Icon., III, 1836, p. 30, pl. xv, fig.
211.—Locarp, Cog. de Fr., 1893, p. 159, fig. 173.

Unio? RossMASSLER, Icon., IIT, 1836, p. 27, pl. xtv, fig. 201.

Unio bandini Kuster, Icon., V and VI, 1837, p. 22, pl. xxiv,
fig. 341. |

Unio glaucinus Porro, Mal. Como., 1838, p. 115.—STABILE,
Faun. Lug., 1845. p. 61, pl. 11, fig. 75.—Koper, Icon., new
Serenll toe0, p19, pla xy, figs 250,

Unio gargotte RossMASSLER,, Icon., VII, 1838, p. 26, pl. xxxv,
fig. 493.—Monterosa‘ro, Nat. Sic., new ser., 1896, p. 6, fig. 1.

? Unio corrugata MAnnuyv, Moll., Vienna, 1839, p. 8.

? Unio rotundata MAnpbuyt, Moll., Vien., 1839, p. 9.

? Unio gangrenosus Scumipt, Bull. Imp. N. H. Moscow, 1840,
p- ?.—Kuster, Conch. Cab. Unio., 1854, p. 124, pl. xxxIv,
figs. 3, 4. |

Sie UNIO

Unio pruinosus ScHMiptT, Bull. Soc. Nat. Mosc., 1840, p. 445.

Unio littoralis var. minor ROSSMASSLER, part. Icon., XI, 1842,
p14, pl: Lv, Ae 744.

Unio manca Mi1Let, Guer. Mag., 1843, p. 4, pl. Lx1v, fig. 2.

Unio mancus Dupuy, Hist. M. Fr., 1852, p. 642. pl. xxvi, fig.
17.—Locarp, Coq. Fr., 1893, p. 156, fig. 170.

Unio moquinianus Dupuy, Moll. Gers., 1843, p. 80, pl—
RossMASSLER, Icon., XII, 1844, p. 31, pl. Lx, fig. 769.—
Kuster, Conch. Cab. Unio, 1854, p. 100, pl. xxvut, figs. 3, 4,
5-—Dupruy, Hist. Moll. Fr., 1852, p. 644, pl. xxv1, fig. 18.—
Mogu1n-Tanpon, Moll. Terr. and Fluv. Fr., 1855, p. 573,
pl. 1, figs. 1, 2—Drourr, Nay. Fr: 111857, p: 88, ple was
foes.

Unio sandri RosSMASSLER, Icon., XII, 1844, p. 26, pl. LvI, figs.
748-750.—KusteEr, Conch. Cab. Unio, 1856, p. 101, pl. Xxvit,
figs. 6, 7.—SoweErRBy, Conch. Icon., XVI, 1868, pl. Lxxix,
fig. 413.

? Unio aleront ComMPpANyo and Massor, Bull. Soc. Agr. Sc.
Pyr..d’Or;, V1, Pt. 2, 1845, p. 234, he. 2-—Kopert, con: TV;
1876, Pp: 04,:pl. CXVILL fie) VES;

Unio badius oxEt,, Mich. Comp., 1831, pl. xvi, fig. 36.

? Unio wolwichi Moreier, Moll. Port., 1845, p. 105, pl. x11,
fio, ale

Wes jacquemini Dupuy, Cat. Ext. Gall. Test., 1849, No. 328;
Hist. M. Fr., 1852, p. 643, pl. xxv, fig. 17—Kosett, Icon.,
V 1) 1870; p; 42; pl. cLxin tis’ LOAD:

Unio droueti Durty, Cat. Ext. Gall. Test., 1849, No. 327; Hist.
Moll. Fr., 1852, p. 630; pixxy, fie. a4.

Unio philippi Dupuy, Cat. Ext. Gall. Test., 1849, No. 335;
Hist. M. Fr., 1852, p: 654,-pl. sex vil, tia. @:

Unio ovalis Dupuy, Hist. Moll. Fr., 1852, p. 637, pl. xxv,
fig. 13:

Unio spinellii Vita, in Moll. Bres., 1852, p. 50, fig. D.

Unio moulinsiana Durvuy, Hist. Moll. Fr., VI, 1852, p. 640, pl.
XXLV,, fig.) LO!

? Unio petterianus Kuster, Conch. Cab., 1854, p. 97, pl. XxXvIt,
fig. 4.

Margaron (Unio) petterianus Lea, Syn., 1870, p. 49.

UNIO 573

Unio capigliolo KustEr, part, Conch. Cab. Unio, 1854, p. 125,
pl. xxxwv, figs. 5, 6.—Sowersy, Conch. Icon., XVI, 1868,
pl. Lxxv, fig. 392——Dupuy, Hist. Moll. Fr., 1852, p. 645,
pl. xxv, fig. 10.

Umio heldi Kuster, Conch. Cab. Unio, 1854, p. 111, pl. xxx,
figs. 5-7.

Unio luxurians Kuster, Conch. Cab. Unio, 1854, p. 119, pl.
MCL, fier? 5.

Unio brevirostris Kuster, Conch. Cab. Unio, 1854, p. 120, pl.
WK RUE. Hos.) 1-3.

Unio natolicus Kuster, Conch. Cab. Unio, 1856, p. 144, pl.
XL, ro A.

Unio turcicus Kuster, Conch. Cab. Unio, 1862, p. 267, pl. xc,
figs. 3, 4.

Unio merdiger Rrerve, Conch. Icon., XVI, 1865, pl. xxvii,
fig. 145.

Var. requieni Rossmassler.

Shell small, rather solid, subrhomboid, considerably inflated.

Length 45, height, 24, diam. 19 mm.

Umo requient RossMASSLER, Icon., XII, 1844, p. 29, pl. Lvu,
figs. 757-761.—Kustrr, part, Conch. Cab. Unio, 1856, p. 126,
pl. xxxvi, fig. 2—Mogu1n-Tanpon, Moll. Terr. et Fluv.
Bre, We 5855, 574.. pl. i, fies: 5-7._Khosent, Icon, VE,
1670. p. 43, pl. CLxIIt, fio: 1647.

Unio nanus Duruy, Hist. Moll. Fr., 1852, p. 640, pl. xxv, fig.
16.—Kosett, Icon., VI, 1879, p. 42, pl. cLxt, figs. 1642,
1643.—Locarp, Coq. de Fr., 1893, p. 154, fig. 168.
Rossmassler figures a number of forms of batavus under

the name requieni. One of these is a small variety that may

bear the above name. The Unio nanus of Dupuy seems to
equal it but, according to Dr. Lea, the original Unio nana of

Lamarck is a small variety of littoralis.

Maton and Rackett do not figure their species, but refer to
several figures. The first is in Ginanni, Opere Postume, 1755,
pl. 1v, fig. 17. This work I have not seen. The figures referred
to in Schréter’s Flussconchylien, in Chemnitz, and the Ency-

574 UNIO

clopedie Methodique (pl. 248, fig. 3) are what we understand
as U. batavus, the latter being the one cited by Lamarck.

Lamarck does not figure his species, but refers to pl.
cexivi, fig. 3, in the Enclycopedie Methodique, which is the
species commonly known as Unio batavis.

This is a very abundant, widespread ‘and variable form.
Every shade of variation long ago received a specific name
and all these have been renamed again and again by the mem-
bers of the new school of conchology. The species has been
repeatedly confounded with the much rarer Margaritana crassa,
which is a larger, ruder and more arcuate form.

Ortmann, (1. c.), follows Thiele. (Suessw. Fauna Deutsch.,
19, 1900, p. 35). in considering the U. crassus Retz. to be this
species. He also follows Haas, (1. c.), in giving priority to
musivus Speng. over batavus 1am. According to Haas, (1. ¢.),
the batava of Maton and Rackett is not the same as Lamarck’s
species of that name, but is probably a form of pictorum, as
this species is not found in England.

Section CAFFERTA Simpson, 1900.

Cafferia Simpson, Syn., 1900, p. 824.

Shell elongated or elliptical, rhomboid when old, solid; beaks
full, the sculpture corrugated zigzag, the ridges often extend-
ing over the disk; epidermis yellowish-brown to nearly black,
dull colored, somewhat sulcate; teeth rather strong; muscle
scars deep, well defined.

Type, Unio caffer Krauss.

Since the publication of the Synopsis I have had the oppor-
tunity of examining gravid specimens of a member of this
section and find that it is a Unio.

Group of Unio caffer.
Characters as in the section.

UNIO CAFFER Krauss.

Shell somewhat elongated, subrhomboid, the posterior point
often drawn downward in old shells, solid, subinflated to in-
flated, inequilateral; beak sculpture zigzag, the beaks being

UNIO 575

only moderately full; posterior ridge full, angled or narrowly

rounded, sometimes partly double, ending below the median

line; anterior end rounded: base line straight, incurved in old
shells, usually full near the posterior end; dorsal line curved ;
dorsal slope curved or obliquely subtruncate; surface irregu-
larly concentrically sculptured, the sculpture being sometimes
broken, subnodulous or slightly zigzagged; epidermis dirty
greenish-yellow or brown; hinge moderately solid; pseudocar-
dinals rugose; laterals somewhat remote; muscle scars well
impressed ; nacre dirty or lurid, yellowish or lead-colored.

Length 67, height 34, diam. 25 mm.

Length 73, height 39, diam. 28 mm.

South Africa.

Unio caffer Krauss, Sud Af. Moll., 1848, p. 18, pl. 1, fig. 14.
Kuster, part, Conch. Cab. Unio, 1856; p: 143, pl. x11,
fig. 2—Hantey, Biv. Shells, 1856, p. 385, pl. xx1, fig. 40.—
Sowersy, Conch. Icon., XVI, 1866, pl. x11, fig. 226.

Margaron (Unio) caffer LEA, Syn., 1852, p. 32: 1870, p. 48.

Nodularia caffer S1MPSON, Syn., 1900, p. 825.

Cafferia caffra Connotiy, Ann, S. A. Mus., XI, 1912, p. 271.

Unio seyheri MEN KE, Zeitschr. Mal., 1848, V, p. 28.

Unio cyamus Priiiprr, Zeitschr. Mal., V, TSE Taps 125.

Unio verreauianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p.
SA A@bs W 1os7-9: 20, pl. xxvii, fig: 167 Jl. Ac. N. Sci.
pital tess. p. 201, pl. XVII, Hg. 16:

Unio verrauianus Sowrrsy, Conch. Icon., XVI, 1868, pl. Lx1x,
fig. 352.

Margaron (Unio) verreaurxianus Lea, Syn., 1870, p. 36.

Unio verreauxt Pater. Conch. Sam., III, 1890, p. 171.

Unio navigoliformis Lea, Pr. Ac. N. Sci. Phila., XI, 1859, p.
152; Ji. Ac. N.-Sci. Phila.; IV,. 1860, p. 248, pl. xxxvut, fig.
124; Obs., VII; 1860, p. 63, pl. xxxvu, fig. 124.—REEVE,
Conch. Icon., XVI, 1865, pl. xx1v, fig. 114.

Margaron (Unio) navigoliformis Lea, Syn., 1870, p. 31.

576 UNIO

Unio natalensis Lea, Pr. Ac. N. Sci. Phila., VIII, 1864, -p.
1133. JLvAc) .N..Se1.. Phila.) V1) 1866, paso pl. xc he see:
Obs., XI, 1867, p. 63, pl. xx, fig. 57-—Sowersy, Conch. Icon.,
x VI 1868, ple Exx fig: 362.

Margaron (Unio) natalensis Lea, Syn., 1870, p. 32.

Unio rectilinearis Sowerby, Conch. Icon., XVI, 1868, pl. Lxv,
he. 232.

Var. africanus Lea.

Shell smaller than U/. caffer, thinner, less inflated, with del-
icate, uneven, concentric sculpture, appearing almost smooth ;
umbonal region sometimes corrugated or having irregular,
zigzag bars: epidermis lurid greenish or greenish-brown ; na-
cre bluish, somewhat iridescent.

Length 45, height 22, diam. 14 mm.

South Africa.

Unio africanus Lea, Pr. Ac. N. Sei. Phila., VIII, 1856, p..94;
jl: Ac. NsJSct Phila: TN 18573 p:, 200) pl. xv oes
Obs., VI, 1857, p. 20, pl. xxvit, fig. 15.—ReeEveE, Conch. Icon.,
XVI, 1865, pl. xx, fig. 100.

Margaron (Unio) africanus Lea, Syn., 1870, p. 48.

Nodularia caffer var. africana SIMPSON, Syn., 1900, p. 825.

Unio caffer Kuster, part, Conch. Cab. Unio, 1856, p. 143, pl.
BSED s1uSi3 Ps

Unio niloticus Kuster, Conch. Cab. Unio, 1856, p. 158, pl. xLv,
fig 5.

Var. vaalensis Chaper.

Shell smaller than the type, rather thinner, more compressed ;
beaks and umbonal region with zigzag sculpture, which
changes with the later growth to granularly sulcate and finally
plainly sulcate; epidermis dull, tawny greenish, or brownish.

Length 40, height 18, diam. 11 mm.

Vaal River, South Africa.

Unio vaalensis CHarer, Bull. Soc. Zool. Fr., X, 1885, p. 480,
ply xi, fies. 153:

Nodularia caffer var. vaalensis SIMPSON, Syn., 1900, p. 825.

UNIO DAT

Var. pentheri Sturany.

“Dr. Penther collected in Panda ma tinka, which is next to
the middle stream of the Zambezi River, two specimens of a
Unio, which are most probably to be referred to U. caffer, but
which differ from the type in shape and proportions, for whic.
reason | shall mention them here under a distinct varietal
name. For greater clearness | also give two figures, one of the
left side and the other of the dorsal aspect.

The two shells measure respectively: length 51.5 and 57;
height 26.5 and 28.5; diam. 18 and 18.5 mm.

The distance from the front and hinder ends is 13: 38.5 in
the smaller specimen and 14 : 43 mm. in the larger.

These proportions point to a near relationship with U. na-
talensis Lea, but that is also a synonym of U. caffer Krss.,
according to F. Smith.” (Sturany).

Unio caffer var. pentheri Sturany, Denks. Math-Nat. Classe K.

Akad. Wissen., LX VII, 1808, p. 627, pl. 111, figs. 64-65.

The above species is an abundant widespread, and variable
one, and has consequently received a number of names. ‘The
variety africanus is much smaller and smoother than the type.
Unio vaalensis Chaper, of which specimens from the type lot
are before me, seems to be merely a small form, possibly young,
in which the posterior point is not depressed. Lea’s Unio
natalensis is evidently a young U. caffer; his verreauianus is
one of the adult forms.

Connolly (1. c.), on the authority of Haas refers both
seyheri and cyamus to this species.

UNIO TRAVERSIT Pollonera.

“Shell olive-brown, somewhat shining, concentrically striate,
pinkish within, rather thick, inflated, ovate-oblong, subrostrate ;
umbones anterior, obtuse, not prominent, eroded; anterior end
~ rounded, narrow; posterior end elongated; with the dorsal
margin, as far as the angle, slightly curved, thence obliquely
curved; ventral margin slightly incurved behind the middle;
area lanceolate; cardinal tooth in the right valve elongate,

578 UNIO

rather stout, crenulate above; lateral tooth elongate, slightly
curved, rugosely granulate posteriorly.

Length 52.5, height 26, diam. 18.5 mm.” ( Pollonera. )

‘Type locality, Hawash River, Shoa, Africa.

Unio travesti PotrLtonera, Bull. Soc. Mal. It., XIII, 1888, p.

Scapleil, Hes. T4505.

Nodularia traversii SIMPSON, Syn., 1900, p. 825.

“This species belongs to the group of U. dembee, but differs
from it very decidedly. Its shell, although not much superior
to the latter in its greatest convexity, has however the appear-
ance of being much more inflated and this comes from the fact
that in the former the curvature of the valves continues reg-
ularly even to the margins, while in the U. dembee the valves
are attenuated and flattened towards the margins. The great-
est difference, however, is on account of the fact that the pos-
terior part is more rostrated and the upper dorsal margin more
curved, the ventral margin is more distinctly incurved, the lat-
eral tooth is shorter and more curved and the area is larger.

It resembles also the U. jickelii Bourg., but may be distin-
cuished from that species by the more anterior position of
the beaks, the more pointed posterior end, the more curved
dorsal margin and the more incurved ventral margin.”

UNIO MASHON@: Preston.

“Shell elongately ovate, rather tumid, covered with a dark
blackish-brown periostracum, sculptured with somewhat coarse
and irregular concentric striz, angled posteriorly; umbones
rather large, prominent though much eroded; dorsal margin
nearly straight ; ventral margin almost straight, but very slight-
ly constricted towards the middle; anterior side rounded above,
sloping below; posterior side produced, bluntly acuminate ; an-
terior lateral teeth very short; posterior laterals long and
coarse; cardinal teeth in right valve wedge-shaped, solid in left
valve, broad, serrated: anterior adductor scar ovate, moderate-
ly deep; posterior adductor scar narrowly fan-shaped, well im-
pressed ; pallial impression coarse, nacreous, pinkish in colour ;
outer margins of interior of shell nacreous, bluish-white.

Long. 80; lat. 37.5 mm.” (Preston.)

UNIO 579

Type locality, A sluit about 16 miles from Eukeldoorn, Ma-
shonaland.

Unio mashone Preston, Ann. Mag. Nat. Hist., (8), VI, 1910,

p. 61, pl. rv, fig. Io.

Cafferia mashone Connotay, Ann. S. A. Mus., XI, IQ12, p.

Ze

“Very similar to caffra, from which it may be separable
through the absence of the umbonal scar.” (Connolly. )
Unio JICKELt (Simpson).

Shell elongated, solid, inflated, very inequilateral, subrhom-
boid; beaks apparently neither full or high; anterior end
rounded and somewhat truncated; dorsal and ventral outlines
nearly straight and parallel, the latter slightly full toward the
hinder end; posterior slope having a long, oblique truncation ;
posterior ridge full, rounded or feebly biangulate, ending be-
low the median line in a faint, narrow biangulation, surface
concentrically sulcated ; epidermis fuscous-olive ; teeth strong;
pseudocardinals short and ragged; muscle scars impressed ;
nacre bluish-white, iridescent.

Length 80, height 30.75, diam. 23.5 mm.

Northeast Africa.

? Unio teretiusculus JicKeLt, Faun. Moll., N. O. Af., 1874, p.

27O np Si, eS: 33° 30,, 3p.

Nodularia jickeli SIMPSON, Syn., 1900, p. 826.
Unio fourtaui PALLARy, Bull. Inst. Egypt, II, 1902, p. 95.

Jickeli figures the above and refers it to Unio teretiusculus
of Philippi with a question. I am sure that it is not that spe-
cies at all, but a larger form with much less intlated umbones,
solider structure, more decided concentric sculpture and
stronger, more ragged pseudocardinals. Jickeli figures the true
teretiusculus as I understand it.

Unio acuminatus H. Adams.

Shell somewhat elongated, decidedly rhomboid, inequilateral,
subinflated, apparently subsolid, beaks full with strong, nod-
ulous, zigzag sculpture, which extends out on to the disk;

580 UNIO

anterior end rounded or subtruncate ; base line straight or near-

ly so; hinge line lightly curved; dorsal slope with a long, de-

cided, oblique truncation; posterior: ridge very full, narrowly
rounded, ending at or near the base in a blunt point; surface
generally having light, concentric growth lines, those becom-
ing stronger and somewhat broken at the anterior end; epi-
dermis yellowish-green ; teeth rather delicate ; pseudocardinals.
subcompressed ; nacre whitish, iridescent.

Length 20, height 15, diam. 10 mm.

Lake Albert Nyanza.

Unio acuminatus H. Apams, Pr. Zool. Soc. Lond., 1866, p.
376.—SMiTH, Ann. and Mag., X, 1892, p. 127, pl. xu, fig.
12.—vVON MArrtENS, Besch. Deuts. Ost. Af., 1897, p. 227, pl.
Vil, ies. 11, D2

Nodularia acuminata SIMPSON, Syn., 1900, p. 826.
Distinguished by its decidedly rhomboid form, the high,

narrowly rounded posterior ridge and the strong, zigzag, nod-

ulous beak sculpture that extends out on to the disk.

UNIO DEMBE Reeve.

Shell somewhat elongated, subrhomboid or subelliptical, sub-
inflated, solid, inequilateral ; beaks moderately full and high;
posterior ridge full, more or less double, ending behind in a
biangulation at and below the median line; dorsal outline ir-
regularly curved; anterior end rounded, slightly angled above ;
base line lightly curved; posterior slope obliquely subtruncated ;
surface with light concentric sculpture; dorsal slope with a
few feeble plications ; epidermis fulvous-olive, tinged and ray-
ed with green; teeth moderately strong, swbcompressed ; mus-
cle scars deep ; nacre pale flesh-color.

Length 66, height 32.75, diam. 21.5 mm.

Length 59, height 29, diam. 19.5 mm.

Abyssinia.

Unio dembee Reve, Conch. Icon., XVI, 1865, pl. Xx1x, fig.

153.—JICKEII, Faun. Moll. Af. 1874, p. 275, pl. 1x, figs. 3-4.
Nodularia dembee@ Stuvson, Syn., 1900, p. 826.

UNIO 581

Reeve’s description is very brief and his figure does not look
like any of the African species I am acquainted with. Jickeli’s
figures are probably more accurate and represent a shell look-
ing something like a short Unio pictoruwm, to which Reeve
likens his shell.

Unio LourDELI Bourguignat.

Shell small, somewhat elongated, inflated, rhomboid, inequi-
lateral, with the greatest diameter behind the middle; beaks
only moderately full, their sculpture apparently zigzag radial
or corrugated ; dorsal line a little curved; anterior end round-
ed; base straight or incurved in old specimens; dorsal slope
obliquely truncated or having a curved outline; posterior ridge
full, rounded, ending at t’*e base of the shell; surface concen-
trically sculptured; epidermis greenish-brown; nacre reddish
or bluish-white.

Length 31, height 16, diam. 12 mm.

Victoria Nyanza Lake.

Unio lourdeli Bourcuicnat, Bull. Soc. Mal. Fr., TV, 1887, p-
271.—SMiITH, Ann. and Mag., X, 1892, p. 128, pl. x11, figs.
13-14.

Nodularia lourdelli Simpson, Syn., 1900, p. 826.

I have never seen this species but from the figures given by
Smith it seeems to be closely allied to U. acuminatus. It 1s
smaller than that species and has stronger and rougher con-
centric sculpture.

Var. smithi Germain.

“Dr. E. A. Smith has figured a beautiful variety of this
species characterized, especially, by its obliquely convex pos-
terior margin and very sinuous ventral margin. I give this
shell the name of variety smithi.” (Germain. )

Unio lourdeli (part), Smiru, Ann. Mag. Nat. Hist. (6), X,

1892, p. 128, pl. x11, fig. 15.

Unio lourdeli var. smithi GERMAIN, Bull. Mus. Hist. Nat. 1905,

A. 306: |

582 UNIO

Unio ABYSSINICUS von Martens.

Shell solid, irregularly ovate or subtriangular, inflated, in-
equilateral; beaks full and high, sculptured with a few smal!
tubercles; hinge line curved; anterior end rounded; base line
evenly curved, full at or behind the middle in young shells, be-
coming nearly straight in old ones; posterior ridge full, slight-
ly double below, ending below the median line in a narrow,
faint biangulation; surface lightly, concentrically sculptured,
the anterior part roughened, the dorsal slope with a few broken
plications ; epidermis olive-yellow, with obscure bands ; pseudo-
cardinals strong, multisuleate; laterals solid; nacre flesh-col-
ored.

Length (adult) 70, height 43, diam. 32 mm.

Length (young) 56.5, height 38.5, diam. 28 mm.

Frana Lake, Abyssinia.

Unio abyssinicus VON Martens, Mal. BL, XIII, 1866, p. 102.—
Jicketi, Faun: Moll N[OFAL 1874p: 278) ple ieanoes.
pl. x; fie} To:

Nodularia abyssinica SIMPSON, Syn. 1900, p. 826.

A decidedly heavy shell, which appears to be close to U.
dembee but is shorter, more solid and somewhat triangular.
In the young shells the base is well rounded and the general
outline is at most regularly oval, but the base line becomes
almost straight with age and it is quite probable that very
old shells may have the posterior point drawn down a little.
Jickeli refers this species to Unio habessinicus Henglin, in
Reise nach Abess., p. 290. This publication is not accessible
to me and [ do not know whether this is a mere nomen nudum
or if it be accompanied with a description. von Martens de-
scribes it as a new species in the Mal. Blatter under the name
of abyssinicus.

Unio MONcET! Bourguignat.

Shell somewhat elongated, rhomboid, inflated, subsolid,
quite inequilateral; beaks only moderately full, with strong
zigzag sculpture; surface rather strongly concentrically sculp-
tured; posterior ridge full, narrowly rounded, curved, ending

UNIO 583

in a blunt point near the base; dorsal and basal outlines nearly
straight, parallel; anterior end rounded, cut away a little be-
low; posterior end obliquely subtruncate ; epidermis greenish-
chestnut; muscle scars well marked; teeth rather delicate ;
nacre reddish.

Length 22, height 10, diam. 8 mm.

Lake Victoria, Nyanza.

Unio monceti Bourcutcnat, Moll. Ny. Ouk., 1883, p. 15, figs

13-15.

Parreysia monceti Stmpson, Syn., 1900, p. 848.

A considerably elongated, inflated, sulcate species, whose
position is somewhat doubtful. It may be closely related to
Unio caffer. I have never seen it.

UNIo DIMINUTUS Lea.

Shell rather small, subcompressed, subsolid, inequilateral,
subrhomboid; beaks small, sharp, somewhat elevated, sculp-
tured with zigzag radial ridges, this sculpture extending well
out over the disk and gradually changing into concentric
ridges ; dorsal outline curved ; anterior end rounded ; base near-
ly straight to behind the middle where it is full; outline of
dorsal slope obliquely curved; posterior ridge only moderately
full, faintly double. ending at and below the median line in a
slight biangulation; epidermis straw-yellow, rayless; teeth
somewhat compressed; nacre pale, satin-like, iridescent, sal-
mon-tinted.

Length 33, height 20, diam. 10 mm.

Fast Africa.

Unio diminutis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 151.
Unio diminutus Lra, Jl. Ac. N. Sci. Phila., IV, 1860, p. 254,

fp se eix tic. 134; Obs. VIP 1860p. 72, pl. xxx1rx, fig. 134.

—ReEEvE, Conch. Icon., XVI, 1865, pl. xxvim, fig. 141.
Margaron (Unio) diminutus Lex, Syn., 1870, p. 31.

Nodularia diminuta StmPpson, Syn., 1900, p. 820.
Unio gratiosus Payrer, Conch. Sam., IIT, 1890, p. 154.

A rather short, subrhomboid, somewhat compressed species,

quite strongly sculptured. It is something like U. vaalensis

584 UNIO

or young caffer, but is higher in proportion to its length and is
not inflated.
The following unfigured species is said to belong here:
Unio mandinguoruwm RocHEBRUNE, Bull. Soc. Phil., 7th ser.,
Ni, 1882, p: 34.
Bakoy, Upper Senegal.

Group of Unio fissidens.

Shell solid, compressed, subelliptical to subrhomboid, with
rather full beaks, which have radiate, corrugate sculpture ex-
tending out on the disk as wavy sulcations, and changing near
the edge to plain sulcations; posterior ridge low, rounded;
hinge strong; right valve with two pseudocardinals, the lower
the larger, showing a tendency to split up, and having a gape
in the plate behind, and having one lateral; two pseudocardi-
nals in the left, somewhat split, and two laterals; muscle scars
deep, distinct.

Unio FISSIDENS Bettger.

Shell subrhomboid, a little higher in front, inflated, solid
and strong, inequilateral; beaks considerably elevated, almost
pointed, their sculpture consisting of rugose, wavy or zigzag
bars, which gradually change farther down on the disk to
strong, concentric ridges; anterior end rounded; base nearly
straight ; dorsal line behind the beaks very slightly curved,
rounding into the obliquely subtruncate posterior slope; pos-
terior ridge rounded, ending in a rounded point near the base;
pseudocardinals of the left valve split up into several radial
denticles, those of the right divided into three, with a triangu-
lar pit behind them; laterals strong, nearly straight; muscle
scars deep.

Length 53-58, height 28.5-33, diam. 20-28 mm.

Kalahari Desert. Southwest Africa.

Unio (Hyridella) fissidens Bovrcrer, Ber. Senck. Ges., 1886,

Po 27; pleitanss. 6a, 6b -7a4gp.

Unio fissidens CONNOLLY, Ann. S. A. Mus., XI, 1912, p. 274.
Nedularia fissidens StMpson, Syn., 1900, p. 827.

UNIO 5385

This appeais to be a very solid species with rather sharply
elevated beaks, the shell being higher in front than behind.
It is strongly and irregularly concentrically sculptured, has
heavy, split-up pseudocardinals, with a deep triangular pit be-
hind those of the right valve. 1 am somewhat uncertain as to
the generic position of this and the next species, never having
seen the shells and knowing nothing of the anatomy, but from
the description and figures I am inclined to think them most
nearly related lo U. caffer.

Unio HyGApPar us Bottger.

Shell somewhat elongated, subrhomboid, subcompressed,
solid, inequilateral; beaks high, rather sharp, indistinctly un-
dulate ; anterior end rounded; base line nearly straight ; hinge
line lightly curved, rounding into an oblique posterior sub-
truncation; posterior ridge rounded, ending in a blunt point
almost at the base of the shell; surface strongly concentrically
sculptured; left valve with two pseudocardinals, the anterior
elongated and curved, crenulate; muscle scars small, the an-
terior ones double, deep.

Length 54, height 26.5 mm.

Kalahari Desert.

Union (Hyridella) hygapanus Borrcrr, Ber. Senck. Ges., 1886,

DB. 20; plas, figs: Sa,.50.

Nodularia hygapanus Simpson, Syn., 1900, p. 827.
Uno hygapanus CoNNouLy, Ann. $. A. Mus., XI, 1912, p. 274.

Apparently nearly related to U. fissidens, but rather more
elongated, less infiated and having pseudocardinals less split

up.
“Described from a single left valve; possibly only a less
highly sculptured form of fissidens.” (Connolly. )

Group of Unio kunenensts.

Shell elliptical, subinflated, solid, narrowly biangulate be-
hind, the point of the shell being about midway up the height,
the post-base inflated; beaks full, eroded in the specimen fig-
ured, but no doubt zigzag sculptured; whole surface of the
shell covered with wavy corrugations ; epidermis brownish ; one

586 UNIO

rather solid pseudocardinal in the right valve, deeply incised,
two in the left : nacre vellowish-white ; muscle scars deep. Ani-
mal unknown.

UNIO KUNENENSIS Mousson.

Shell irregularly elliptical or subovate, inequilateral, subin-
flated, solid; beaks moderately full and elevated; posterior
ridge somewhat double, ending behind about on the median
line in a distinct biangulation; dorsal outline curved; anterior
end rounded; base straight to behind the middle where it is
angled and obliquely truncated to the posterior end; dorsal
slope obliquely truncated; surface covered with irregular,
somewhat granulose, concentric sculpture, which in places be-
comes zigzagged ; epidermis apparently brownish; teeth rather
strong; nacre bluish-white, salmon-tinted in the cavities; an-
terior muscle scars deep.

Length 38, height 25, diam. 23 mm.

Head of Kunene River, North Ovampo, Southwest Africa.
Unio kunenensis Mousson, Jl. de Conch., XXXV, 1887, p-

300, pl. x11, fig. Io.

Nodularia kunenensis SIMPSON, Syn., 1900, p. 824.

The distinct posterior biangulation, and the peculiar sculp-
ture varying from granulous concentric to zigzag will distin-
guish this species from others. The,statement made by Mous-
son that the length of this shell is 28 millimeters is no doubt
an error, as the figure shows it to be 38.

Section E1.iprio Rafinesque, 1810.

Elliptio Rarinesgur, J.. de Phys., Chimie, Hist. Nat.,
LXXXVIII, 1819, p..426—OrtMann, Ann. Car. Mus. VIII,
1OI2, p. 265.

Shell elongated, rhomboid or oval, usually more or less bi-
angulate behind; beak sculpture consisting of a few rather
strong ridges, which are nearly parallel to the growth lines
or slightly doubly looped; the surface smooth or feebly corru-
gated.

Type, Unio crassidens Lamarck.

Ortmann, (1. c.), raises this group to generic rank.

“J

UNIO 58

Group of Unio coloratus.

Shell somewhat rhomboid, solid, slightly biangulate behind,
rather compressed, more or less sculptured with concentric
sulcations; beaks moderately prominent, their sculpture un-
known ; epidermis brownish; teeth strong; laterals rather club-
shaped ; nacre white or purple. Animal unknown.

Unto cororaAtus Charpentier.

Shell subrhomboid, convex, solid, densely sculptured with
fine striations ; epidermis brownish-olive ; beaks rather full, pos-
terior ridge moderate, scarcely double, ending in a feeble bian-
gulation near the base; pseudocardinals thick, serrated; nacre
dark purple, shining.

Medellin River, Vera Cruz, Mexico.

Unio coloratus CHARPENTIER, in Kuster, Conch. Cab. Unio,
1856, p. 155, pl. xiv, fig. 6 —StmMpson, Syn., 1900, p. 700.
Unio cuprinus var. coloratus, VON MARTENS, Biol. Cent. Amer.,

Moll., 1900, p. 506.

I am strongly inclined to believe that this and Lea's Unio
callosus are identical. The figures show Charpentier’s shell to
be a little straighter than Lea’s on the base, otherwise the out-
lines and figures agree very closely. Both authors claim that
their shells are compressed, but the outline figures of dorsal
views show them to be quite convex. l[ea’s shell has white
nacre while that of Charpentier’s is dark purple, but this is
often a difference of no importance, for the same thing occurs
in Unio complanatus, U. buckleyi, Tritogonia tuberculata and
many other species. I have seen a single specimen belonging
to Mr. Berlin H. Wright, which I was inclined to refer to this
species, though it did not fully agree with the description and
figure.

UnNIo cALLosus Lea.

Shell rhomboid elliptical, convex, solid, inequilateral with a
moderate, feebly biangulate posterior ridge, which terminates
behind a short distance above the basal line; beaks somewhat
prominent but eroded in the type; epidermis yellowish-brown.

588 UNIO

darker and wrinkled on the posterior slope; pseudocardinais

small, double in both valves; laterals heavy, long, and curved;

muscle scars rather deep; beak cavities small and angular;
nacre white and iridescent.

Length 57, height 35, diam. 23 mm.

Said to come from the Ohio Canal below Columbus. I am
sure that the locality is wrong, and it appears to be a Mexican
form.

Unio callosus Lea, Pr. Am. Phil. Soc. II, 1841, p. 31; Tr. Am.
Phil. Soc. VII: 1842,. p. 230, plo xxi, tie. 254 Obane las
1842, p. 77, pl. xx1u, fig. 54.—CHENU, Ill. Conch., 1858, pl.
XXVI, figs. 4, 4a, 4b.—Simpson, Syn., 1900, p. 701.

Margaron (Unio) callosus Lea, Syn., 1852, p. 33; 1870, p. 33.
I cannot believe it possible that the shell Lea described,

which belonged to Dr. Jay, came from the Ohio Canal 12

miles below Columbus. The region around Columbus, Ohio,

has been as thoroughly collected out perhaps as any in the

United States and nothing like this shell has ever been found

there so far as I know. It seems to me to be very closely

allied to U. coloratus Charpentier, if not absolutely identical
with it, and it is in all probability a Mexican species.

Unio MEXICANUS Philippi.

Shell rhomboid, rather solid subinflated, its greatest diame-
ter being considerably behind the beaks, with a rather strong
rounded posterior ridge; beaks high, somewhat full, their sculp-
ture not observed ; epidermis fuscous ; pseudocardinals strong ;
laterals elongated, nearly straight; nacre purple and shining.

Length 64, height 37, diam. 23 mm.

Mexico.

Unio mexicanus Purr, Zeits. fir Mal., IV, 1847, p. 95.—
Putter, Abbild. und Beschr., III, 1849, p. 110, pl. v1, fig. 3.
—Kuster, Conch. Cab. Unio, 1862, p. 285, pl. xcv, fig. 7.—
SIMPSON, Syn., 1900, p. 7OI.

Margaron (Unio) mexicanus Lea, Syn., 1870, p. 53-

Philippi gives a miserable colored figure of this species,
which is so blurred that it is almost useless for purposes of

UNIO 589

identification, while his brief Latin description helps out but
little. Kuster copies his figure, but adds nothing to our knowl-
edge of the species. In the Lea collection there is a single,
rather young shell, which was received from Wheatley which
is labeled “Unio mexicanus Philippi, Mexico,” and it may be
Philippi’s species. It is rather more inflated in front than be-
hind, is not quite so decidedly obliquely truncate behind as the
figures of mexicanis show it to be, but it has a brown epider-
mis, and pale violet nacre. It may be a young opacatus.

Group of Unio semigranosus.

Shell triangular rhomboid, solid, inflated, with a distinct
posterior ridge; beaks rather full, their sculpture consisting of
‘numerous somewhat irregular corrugations, which pass into
the pustulous sculpture of the shell; surface of the valves gen-
erally more or less sculptured with chevron-shaped or zigzag
ridges or corrugations, which often break into pustules, the
posterior slope bearing curved, radiating plications, which are
likewise sometimes nodulous; epidermis dark, scarcely rayed ;
pseudocardinals strong, radial, ragged ; laterals heavy, oblique-
ly striated; beak cavities not deep, compressed; muscle scars
well impressed; nacre purple, with bronzy or coppery shades.

Animal apparently not different from that of other related
Unios. I have not seen any with the marsupium filled.

Unio PLEXUS Conrad.

Shell subrhomboid, inflated, solid, inequilateral, with a fairly
well developed posterior ridge, which is generally feebly bian-
gulate ; beaks full and high, their sculpture not observed ; dor-
sal outline behind the beaks curved; anterior end rounded ;
base straight to slightly rounded; posterior end usually feebly
biangulate: surface usually sculptured with radiating, curved
corrugations on the disk; these are divaricate on the posterior
ridge and they often become somewhat nodulous. Sometimes
the shell is destitute of sculpture except on the posterior slope ;
epidermis black or dark reddish-brown, shining when worn or

590 ONIO

rubbed; left valve with two stumpy pseudocardinals and two

laterals, the upper smaller; right valve with one ragged pseu-

docardinal and one, often partly double, lateral; muscle scars
impressed, the anterior ones rough; beak cavities shallow,
showing numerous dorsal scars; nacre purple or coppery.

Length 55, height 35, diam. 24 mm.

Length 48, height 30, diam. 25 mm.

Mexico, in the vicinity of Vera Cruz.

Margarita (Unio) carbonarius LEA, Syn., 1836, p. 192; 1838,
Dalz

Unio carbonarius Lea, Tr. Am. Phil. Soc., VI, 1838, p. 37, pl.
*1, fig. 32; Obs., II, 1838, p. 37, pl. x1, fig? 32.— HANEY,
Biv. Shells, 1843, p. 184, pl. xxu, fig. 10—CuHENu, IIl.
Conch:, 1858, pl. xxi, figs. 1, 1a, 10.

Margarita (Unio) pliciferus Lea, Syn., 1836, p. 13; 1838, p.
TA:

Unio pliciferus Lea, Tr. Am. Phil. Soc., V, 1838, p. 61, pl.
XVI, nig. 535 Obs. 1, 1838, p60, pl xvi fees setae
LEY, Biv. Shells, 1843, p. 176, pl..xx, fig. 32-—KUSTER,
Conch. Cab., 1848, p. 142, pl. xu, fig. 1—CuHeENu, Ill.
Conch., 1858, pl. xxi, figs. 5, 5a, 5b; Manual, 1859, II, p.
142, fig. 702.—Sowersy, Conch. Icon., XVI, 1868, pl. Lxxv,
fig. 387.—FiscHER and Crossk, Miss. Sci. I, 1894, p. 580.
pl LXV, ns) 2 exe figs) 2: 2a:

Margaron (Unio) pliciferus L&A, Syn., 1852, p. 20; 1870, p. 31.

Unio plexus Conrap, Monog., X, 1838, p. 89, pl. xLix, figs.
1, 2.— SIMPSON, Syn., 1900, p. 701.

Var. minor Fischer and Crosse.

Shell considerably smaller than the type, the epidermis in
the specimens examined brownish and shining.

Length 35, height 20, diam. 14 mm.

Habitat with the typical form in East Mexico.

Unio pliciferus var. minor, Fisctter and Crossr, Miss. Sci. I,
1834, p. 580, pl. LXrx, fig. 4—von Martens, Biol. Cent. Am.,
Moll., 1900, p. 515, pl. XXxX1X, figs. 4, 4a.

UNIO 591

The names carbonarius and pliciferus were published by
Lea for this species two years before plexus appeared, but were
unaccompanied by descriptions. ‘The species seems to be a
very abundant one, but I have not heard of specimens being
found elsewhere than in the vicinity of Vera Cruz. It is
smaller, darker and more inflated, than any member of this
group.

Unio CROCODILARUM Morelet.

Shell solid, inflated, irregularly elliptical or ovate, more
rounded on the dorsal outline than on the base; posterior ridge
well developed, sometimes slightly double and ending in a
blunt point or feeble biangulation behind; beaks full and high,
their sculpture consisting of wrinkled, subpustulous bars; sur-
face either covered with close irregularly radial, subnodulous
ridges, which often break into regular pustules or smooth;
these nodules do not extend to the border of the shell; epider-
mis greenish in young shells, becoming brownish later on and
black in fully mature shells; left valve with two radial, ragged
pseudocardinals, the space between them torn and often aris-
ing into a low third tooth, with two remote laterals; right
valve with a single strong pseudocardinal and sometimes a
small one above, and one somewhat double lateral; beak cavi-
ties well impressed, their dorsal scars under the pseudocardi-
nals; muscle scars rather deep, the anterior ones rough; nacre
purplish-coppery or bronzy, sometimes white, thicker in front.

Length 90, height 55, diam. 41 mm.

Rio Usumacinta, Guatemala.

Unio crocodilarum More.et, Test. Nov., I, 1849, p. 28.—
Reeve, Conch. Icon., XVI, 1864, pl. x, fig. 37.—F1scHer and
Grosse, Miss. sScr-/LL 1004. “p.. 577. Di Lx, figs. 3, 4, 53
LXVII, fig. 3. IPSON, Syn., 1900, p. 702.—VON MARTENS,

S

SIN
3iol. Cent. Amer., Moll., 1900, p. 495, pl. xxx1, figs. 3, 3a,
b, ¢.

? Unio rusticus SowrErry. Conch. Icon., XVI, 1868, pl. LxIv,

fig. 324.

592 UNLO

Fischer and Crosse have made two varieties of this in the
Mission Scientifique, semipustulata with pustules over half the
surface and white nacre and prestricta, which is shorter, more
inflated with tubercles near the beaks. The examination of a
number of shells shows so many cross characters that I hardly
think these varieties need to stand. The species is more in-
flated and not nearly so high as semigranosus. | have seen a
large shell that was absolutely destitute of sculpture save some
slight traces of tuberculation near the beaks.

UNIo MoRiNI Morelet.

Shell very inequilateral, long subrhomboid, compressed,
solid, with a distinct double posterior ridge, which ends in a
rather wide biangulation behind; beaks rather full, their sculp-
ture not observed; surface covered with decided concentric
ridges, which are covered with small granulations or fine nod-
ules, which are arranged in radiating rows, bifurcating on the
posterior ridge; epidermis brown; left valve with two pseudo-
cardinals, the anterior one bifid, the posterior small and oblique,
with two laterals, the lower larger; right valve with one bifid
pseudocardinal and one lateral; anterior muscle scars deep and
rough; posterior scars shallow; nacre white, shaded blue or
pale rose.

Length 75, height 47, diam. 28 mm.

Rio Usumacinta, Guatamala.

Unio morini Morevet, Test. Nov., II, 1851, p. 24.—FISCHER
and Crosse. Miss. Sci.j EL, 480459. 576; ple xa. 2 eee
fig. 4SIMPSON, Syn., 1900, p. 702.

This seems to differ from U. crocodilarum in having the
beaks placed much farther forward. It is more compressed
and wider behind than that species or U. plexus, and the de-
cided double posterior ridge is a good character, if constant.

UNIo SEMIGRANOSUS von dem Busch.

Shell subtriangular, subcompressed, rather solid with a low,
scarcely double posterior ridge; the region of the beaks promi-
nent, but the beaks themselves low and compressed, their sculp-

UNIO 593

ture consisting of irregular, subnodulous ridges; surface more

or less covered with close set, small tubercles, which sometimes

form nodulous or corrugated bars, especially on the posterior
slope, the border of the shell smooth; epidermis yellowish-
brown; base line straight or slightly curved; post-dorsal line
almost evenly curved from the beaks to the base, but sometimes
showing a faint, biangulation below; left valve with two rag-
ged, subcompressed pseudocardinals and two remote laterals,
the hinge line between the two sets of teeth. very narrow ;
right valve with two pseudocardinals, the upper smaller and
one, sometimes slightly double, lateral ; beak cavities compress-
ed, moderately deep; muscle scars shallow, the anterior ones
rough; nacre coppery, thicker in front; pallial line rather dis-
tant from the border.

Length 110, height 65, diam. 32 mm.

Mexico, Vera Cruz to Tampico.

Unio semigranosus VON DEM Buscu, (in Philippi), Abbild. und
Besch., I, 1845, p. 109, pl. 1, figs. 1-3—Hantey, Biv. Shells,
1856, p. 381. pl. xx, fig. 33—lKuster, Conch. Cab. Unio,
1861, p. 252, pl. L.Xxxv, fig. 1—Simpson, Syn., 1900, p. 702.
—Vvon Martens, Biol. Cent. Amer., Moll., 1900, 493, pl.
May, figs. I-4.

Margaron (Unio) semigranosus Lea, Syn., 1852, p. 20; 1870,

P- 34-
Ouadrula semigranosa Piispry, Pr. Ac. Nat. Sci. Phila., 1909,
P- 532:

Unio carbonarius var. semigranosus Pavey, Conch. Sam., ITI,

TOOO; Pp. 147.

The Lea collection contains a fine specimen of this shell
presented by von dem Busch, and I have given its measure-
ments above. It is a little straighter on the base, and a trifle
more elongated than the specimen figured in Philippi, but it
is a more adult shell.

Unio cortum Reeve.

Shell long rhomboid, subcompressed, with a low, somewhat
double curved, posterior ridge, with rather high full beaks,
whose sculpture is not known; surface covered with close-set

594 UNIO

pustules, which fade out at the border of the shell; epidermis

dull olive ; nacre rose purple.

Length 98, height 64 mm.

State of Chiapas, Mexico.

Unio corium Rrrve, Conch. Icon., XVI, 1864, pl. x, fig. 39.—
Simpson, Syn., 1900, p. 702.—von Martens, Biol. Cent.
Amer., Moll., 1900, p. 495, pl. xxx, figs. 4, 4a, 40.

I am strongly disposed to regard this as merely an old
arcuate Unio semigranosus. I have seen a shell; which in
form stands about midway between Reeve’s figure corium and
that of von dem Busch’s semigranosus, which I at first re-
ferred to this species, and afterwards to that of von dem Busch.
The shell figured by Reeve has fuller, higher beaks than semi-
granosus. The group containing this and related species is a
very puzzling one and [ cannot be certain what species should
stand in it from the limited amount of material | have seen.

Unio pistincrus Crosse and Fischer.

“Shell inequilateral, transversely oval, slightly inflated, sub-
rostrate posteriorly, thick, heavy, covered with an olive-brown
epidermis with concentric and strong striz, regularly and finely
reticulate towards the beaks, radiately plicate posteriorly ; an-
terior end subangulate; posterior subtruncated ; area obscurely
marked and subangulated; ventral margin curved, slightly
sinuous; dorsal margin curved in both directions; beaks
scarcely projecting, somewhat eroded. Nacre of a beautiful
coppery-brown, tinged with purple. Right valve with two
short, unequal cardinals much grooved and ragged, (the lower
much larger and thicker than the upper), with a small, oblique,
grooved denticle behind them ; lateral tooth oblong and oblique.
left valve with two cardinals, the anterior thick and larger,
the posterior shorter, granular, grooved; lateral teeth two,
lamelliform, elongated, unequal, the lower more prominent.
Cicatrices of the anterior adductors deep, rugose, irregularly
oval; those of the posterior adductors superficial, larger and
subcircular. Ligament quite thick, brownish.

Length 79, height 50, diam. 33 mm.” (Crosse and Fischer).

UNIO 595

Type locality, Rio Cosamalcapam, near Chacoltianguiz,
State of Vera Cruz. Mexico.

Unio distinctus Cross and Fiscuer, Jl. de Conch., XLI, 1893,
p. 110;—Fiscner and Crosse, Miss. Scient. Mex., Moll.
II, 1894, p. 579, pl. Lx1x, figs. 2, 2a.

Unio semigranosus var. distinctus, VON MARTENS, Biol. Cent.
Amer., Moll!., 1900, p. 494.

“Unio distinctus belongs to the group of U. psoricus More-
let. but it is less elevated, more transverse, more angular in
front and the beaks are less inflated. It is to some extent inter-
mediary between that species and U. crocodilarum Morelet, a
form quite transverse and elongate.”

UNIo TESTUDINEUS Morelet.

Shell subequilateral, triangular ellipitical, compressed, solid
with an olive-green epidermis, with strong concentric growth
lines, covered densely with tubercles throughout the surface;
posterior ridge low, scarcely biangulate ; anterior end obliquely
truncate above; base rounded; beaks rather high, their sculp-
ture not observed. Left valve with two ragged pseudocard-
inals and two laterals, right valve with two pseudocardinals,
the upper compressed and small and one lateral; anterior mus-
cle scars deep; posterior scars shallow ; nacre coppery-purple.

Length o1, height 70, diam. 34 mm.

Rio Usumacinta, Guatemala.

Unio testudineus Morrier, Test. Nov., os 1849, p. 28.—FIscH-
ER and Crosser, Miss. Sei Ee srees, fe +571, pls. Lx, fig:
3; LXx, fig. 3—Srimpson, Syn., 1900, p. 702.

Unio semigranosus Rerve, Conch. Icon., XVI, 1864, pl. x
36.

Unio semigranosus var. testudineus VON Martens, Biol. Cent.
Amer., Moll., 1900, p. 493.

This species seems to differ from U. psoricus in being more

compressed, and in having tubercles all over its surface.

Unto psortcus Morelet.

Shell subtriangular, inequilateral, subdepressed, solid, with a
moderate, sometimes double, posterior ridge; anterior end
angulated and rounded; beaks rather high but not inflated:

596 UNIO

beak sculpture consisting of faint, doubly-looped, granulous
ridges; surface covered, except a narrow peripheral border
which is wider behind, with strong, irregular, closely set tuber-
cles, the outer border being smooth; epidermis tawny, brown-
ish or greenish, clouded; left valve with two very ragged,
partially united pseudocardinals and two curved laterals; right
valve with two pseudocardinals, the upper smaller and one
lateral, sometimes with a feeble second one; beak cavities
moderately deep, compressed; anterior scars rough; nacre
coppery-purple, considerably thickened in front; pallial line
remote from the border, especially in front.

Length 83, height 63, diam. 43 mm.

Length 74, height 55, diam. 30 mm.

Rio Usumacinta, Guatemala.

Unio psoricus Morrtet, Test. Nov., Pt. 2, 1851, p. 25.—FIscH-
ER and Cross, Miss. Sci., LI, 1894, p. 572, pl. Lx1, fig. 2.—
Stmpson, Syn., 1900, p. 703.—voN Martens, Biol. Cent.
Amer., Moll., 1900, p. 494, pl. xxx1, figs. I, 1a, 2.

A fine specimen of this in the Lea collection agrees very well
with the description and figure of Fischer and Crosse. It is
shorter and more triangular as well as solider than the nearly
allied U. semigranosus of Lea. The posterior slope of this
species shows slight radiating granulous ridges. The beak
cavities of this and some related species are compressed and
are deeper than they usually are in Unio and though the form
of the shell is nearest to that of members of this genus it is
possible that these species should be placed in Quadrula.

Group of Unio gibbosus.

Shell solid, compressed or inflated, triangular ovate to elong-
ateovate, arcuate when old, gibbous above, pointed or slightly
biangulate behind, with a moderate posterior ridge; beaks low,
the sculpture consisting of a few very strong ridges, which
run parallel with the growth lines; epidermis dull and cloth-
like; pseudocardinals strong, rough; laterals granular or ver-
tically striated, club-shaped; beak cavities very shallow, one
or more slight furrows or ridges occur in the cavity of the

UNIO 5O7

shell, which run nearly parallel with the laterals; muscle scars
very deep and distinct.

Marsupium occupying the entire outer gills; branchie large,
curved below, inner the wider except at the posterior end, free
from the abdominal sac only part of their length; mantle very
thin, with thickened edge; branchial opening generally large.

Unio crprosus Barnes.

Shell elongated, generally solid, rarely inflated, sometimes
subcompressed, decidedly inequilateral, usually a little higher
in front and often arcuate, especially in an adult state; beaks
not much elevated above the curved dorsal line, generally sub-
compressed, turned a little forward over a_ well-developed
lunule, their sculpture a number of strong, often rude, sub-
corrugated, longitudinal bars. which are sometimes slightly
doubly looped; posterior ridge well developed, subangular or
rounded, curved and placed close to the dorsal line, rarely dou-
ble and ending behind in a point or biangulation at or near the
base of the shell; surface with uneven growth lines, sometimes
concentrically sculptured: epidermis dull, greenish or yellow-
ish-brown in young shells, darker when old, often faintly raved
in young specimens; left valve with two rather small, stumpy
or subcompressed pseudocardinals; right valve with one, hav-
ing occasionally a vestigial tooth in front of and behind it;
laterals club-shaped, one in the right valve which is sometimes
double, and two in the left ; beak cavities exceedingly shallow ;
dorsal scars immediately under the hinge; muscle scars deep;
pallial line impressed, crenate; nacre deep purple, salmon,
straw-colored or white, obliquely ribbed.

Length 145, height 68, diam. 45 mm.

Length 125, height 56. diam. 26 mm.

Length 123, height 65, diam. 29 mm.

Length 109, height 47, diam. 30 mm.

Entire Mississippi drainage; St. Lawrence and its tributar-
ies; Alabama River system; southeast into Florida; southwest
to the Guadalupe River. Texas.

Type locality. Wisconsin.

Unio nasuta L.AMARCK, An. sans Vert., VI, 18109, p. 75.
Unio nasutus Acassiz, Arch. fiir Nat., I, 1852, p. 50.

598 UNIO

Unio gibbosus Barnes, Am. jl. Sci., VI, 1823, p. 262, pl. x1,
fig. 12.—HAn ey, Biv. Shells, 1843, p. 207, pl. xx, fig. 54.—
Kuster, Conch. Cab. Unio, 1852, p. 28, pl. 1v, figs. 3, 4.—
SoweERBy, Conch. Icon., XVI, 1868, pl. Lxxut, fig. 379.—
BAKER, Moll. Chicago, 1808, p. 70, pl. xiv, figs. 3, 4; Xv,
figs. I-4.—SIMPSON, Syn., 1900, p. 703.

Margarita (Unio) gibbosus Lema, Syn., 1836, p. 38; 1838, p. 25.

Margaron (Unio) gibbosus Lea, Syn., 1852, p. 38; 1870, p. 61.

Mya gibbosa Eaton, Zool. Text-Book, 1826, p. 220.

Elliptio gibbosus ORTMANN, Ann. Car. Mus., VIII, 1912, p.
221.

Unio mucronatus BARNES, Am. Jl. Sci., VI, 1823, p. 266, pl.
Kilt, US Tse othe).

Mya mucronata Eaton, Zool. Text-Book, 1826, p. 221.

Unio dilatatus Say, Am. Conch., VI, 1834.—Conrap, Monog.,
V, 1836, p. 42, pl. xx1.—Kusrer, Conch. Cab. Unio, 1852,
p. 38, pl. vi, fig. 4.

Unio torulosus Frrussac, Guer. Mag., 1835, p. 28.

Unio arctatus Ferussac, Guer. Mag., 1835, p. 29.

Unio arctior Lea, Vr: Am, Phil. Soc, VI, 18385 p. 10; pli,
fig. 10; Obs., II, 1838, p. 10, pl. iv, fig. 10 —HANLeEy, Biv.
Shells. 1843, p. 208, pl. xxtr, fg. 46.—Kuster, Conch. Cab.
Unio, 1861, p. 170, pl. Lvi, fig. 6 —CHENU, II]. Conch., 1858,
pl. xxI, figs. 2, 2a, 2b.—?Sowersy, Conch. Icon., XVI, 1868,
pls eK KV, hig 22:

Margarita (Unio) arctior Lea, Syn., 1836, p. 39; 1838, p. 25.

Margaron (Unio) arctior LEA, Syn., 1852, p. 38; 1870, p. 7I.
A species having an immense distribution in no less than

four distinct drainage systems and very abundant in individ-

uals. Certain specimens superficially resemble specimens of

Ptychobranchus phaseolus in form and the shape of the teeth,

but the marsupia are very different in these species and the

shells of gibbosus have different color pattern and duller col-
ored nacre. Some of the variations of this species are probably
worthy of names.

UNIO 599

Var. arcus Conrad.

Shell small, thick and ponderous, subintlated, arcuate.
Length 50, height 25, diam. 21 mm.
Alabama River drainage, probably merges into subgibbosus.
Type locality, Alabama River.
Umio arcus Conran, Am. Jl. Sci. XXV, 1834, p. 340, pl. 1, fig.
8.— Han ey, Biv. "Shells, 1843, p. 267, pl. xxi, fig. 46.
Margarita (Unio) arcus LEA, Syn., 1836, p. 38; 1838, p. 25.
Margaron (Umo) arcus LEA, Syn., 1852, p. 38; 1870, p. 61.
Unio gibbosus var. arcus SIMPSON, Syn., 1900, p. 704.

Var. subgibbosus Lea.

Shell small, solid, inflated or subinflated, with a high pos-
terior ridge. Typically subrhomboid and slightly full on the
base line.

Length 54, height 29, diam. 18 mm.

Alabama River system; Saline River, Arkansas.

Type locality, Oostanaula, Floyd Co. ; Etowah River, Ga.
Unio subgibbosus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p.

160 4, [Aga N — Sei: Philas, WV ,, 1858;. p:-53, «pl. vi, fig: 26;

Obs., VI, 1858, p. 53, pl. v1, fig. 36—Srmpson, Pr. U. S.

Nat. Mus., XV, 1892, p. 432, pl. Lxxvitt, fig. 5.

Margaron (Unio) subgibbosus LEA, Syn., 1870, p. Ot.
Unio lasarus Sowerby, Conch. Icon., XVI, 1868, pl. Lxvut,

fig. 348.

Umiovrnjus LRA Pre AGN. Sch. hild.,, 1X,’ 1857, p.171.;. JI.

Aer N-voct. Phila TV, 1858;:p.-85;.pl: xvi, fic. 6s.
Margaron (Unio) rufus LEA, Syn., 1870, p. 61.

Unio gibbosus var. subgibbosus Stmpson, Syn., 1900, p. 704.

Varies from the above form into arcus and armathwaitensis.
Var. armathwaitensis B. H. Wright.

Shell narrowed in front, widest behind, subcompressed, sub-
solid.

length 87, height 40, diam. 19 mm.

length 65, height 34, diam. 17 mm.

600 UNIO

Type locality, Branch of South Fork of the Cumberland
River, Armathwaite, Fentress Co., Tennessee; also Mammoth
Cave, Green County, Kentucky.

Unio gibbesus var. armathwaitensis B. H. Wricut, Naut., XI.

1898, p. 123.—Si1MPSON, Syn., 1900, p. 704.

Var. delicatus Simpson.

Shell subsolid or rather thin, subcompressed or compressed,
subrhomboid or almost evenly elliptical, never arcuate.

Length 98, height 36, diam. 18 mm.

Greenway, Clay County, Arkansas; widely distributed in
the Mississippi valley and into Michigan.

Unio gibbosus var. delicatus SIMPSON, Syn., 1900, p. 704.

Much more delicate than the type, rather thin, compressed, :
not arcuate.

UNIO STONENSIS Lea.

Shell oblong, irregularly elliptical or subrhomboid, solid,
compressed or subcompressed, inequilateral; beaks scarcely
elevated above the dorsal line, compressed, somewhat pointed
and turned forward over a narrow lunule, their sculpture
consisting of moderately to quite coarse, subcorrugated ridges
that follow the growth lines; posterior ridge well marked,
somewhat double, running near the dorsal line and ending
behind in a feeble biangulation below the median line; ante-
rior end rounded ; dorsal line curved; base line slightly curved
or nearly straight; surface with rude, uneven growth lines;
epidermis tawny or tawny-brown; left valve with two stumpy,
striated pseudocardinals the anterior small and two short, re-
mote, slightly curved laterals; right valve with one pseudo-
cardinal, the hinge being radially striate before and behind it
and showing vestiges of teeth, with one strong, granulated
lateral; beak cavities very shallow; dorsal scars close to the
hinge plate; muscle scars deep and smooth; nacre white, some-
times salmon-tinted in the center, a little thicker in front,
obliquely furrowed.

Length 84, height 47, diam. 22 mm.

UNIO 601

Type locality, Stones River, Tennessee. Also Roanoke

River and Southwestern Virginia.

Unio stonensis Lea, Pr. Am. Phil. Soc., I, 1840, p. 286; Tr. Am.
Phileooc., ViILLG 1841, p:.195, pl.<viil, fig..5 Obs., ITI,. 1842,
p. 33, pl. vu, fig. 5.—CueEnu, Lil. Conch., 1858, pl. xxix,
figs. 7, 7a, 76.—Sowersy, Conch. Icon., XVII, 1868, pl.
LXXXVI, fig. 462.—SIMPSON, Syn., 1900, p. 705.

Margaron (Unio) stonensis LeA, Syn., 1852, p. 27; 1870, p. 43.
The type was received by Dr. Lea from Mr. Edgar, and is

said to have come from Stones River, ‘'ennessee. Another shell

in his collection agreeing with this was donated by Dr. Sho-
walter and is said to have come from Yellow Sulphur Springs,

Montgomery County, Virginia, Roanoke River. Other shells

are in the Lea collection from Dr. Showalter, labeled Unio

racensis, said to come from the Roanoke River, in Washington

County, Virginia, which are very close to, if not identical with

stonensis. Washington County is in the southwestern part of

the state and all the streams in it flow into the Tennessee River.

Lastly I have seen other specimens in the collection of T. H.

Aldrich, said to come from the Roanoke River, Virginia, which

agree in most characters with the shell said to be from Stones

River, Tennessee. Some of the Virginia shells are a little

darker colored and are somewhat more rhomboid than the

type; part of them have white nacre and there are others with
various shades to deep purple. It seems almost improbable
that the species should be found in the Tennessee and Roanoke
systems, though it is no more remarkable than the similar dis-
tribution of Lampsilis constricta. 1 am at a loss to know
where to place this shell. Lea believed it to be near to Unio
gibbesus and the tvpe would seem to indicate such a relation.

Some of the Virginia material seems to show decided relations

to Unio complanatus.

Unio Luripus (Lea).

Shell irregularly elliptical or subrhomboid, compressed or
subcompressed, rather solid, inequilateral; beaks apparently
but little elevated, their sculpture not observed ; posterior ridge

602 UNIO

subangular or somewhat rounded, often somewhat double,

ending behind a little below the median line, usually in a faint

biangulation; surface unevenly concentrically striate; epider-
mis, finely lamellose, dull olive or dirty green, rarely showing

a few faint rays; left valve with two low, stumpy pseudocard-

inals and two laterals; right valve with one or two pseudo-

cardinals, the upper apparently small, and one lateral; nacre
bluish-white, tinted with flesh-color in the cavities, with an
oblique furrow.

Length 50, height 26, diam. 14 mm.

Georgia; Florida; Yadkin River, North Carolina?

Type locality, Coosawattee River, Murray Co., Ga.

Unio luridus Lea, Tr. Am. Phil. Soc., X, 1852, p. 273, pl. xx,
fig. 29; Obs., V, 1852, p. 29, pl. xx, fig. 29.—SIMPSON, Syn.,
Igoo, p. 705.

Margaron (Unio) luridus Lea, Syn., 1852, p. 30; 1870, p. 48.
Possibly only a small variety of U. gibbosus. It has no

decided characters, but is small, compressed, moderately solid,

and usually a little produced in the post-basal region.

Group of Unio discus.

Shell large, solid, compressed, subtriangular ; biangulate be-
hind; beak sculpture not seen; beaks high, but not swollen;
epidermis dark, rough; teeth heavy: laterals remote, club-
shaped; nacre white, yellow, or purple.

Animal unknown.

Unio piscus (Lea).

Shell large, subtriangular, compressed, solid, inequilateral ;
beaks high but compressed, their sculpture not seen; posterior
ridge low. double, ending behind in a biangulation about at
the median line; anterior end narrowed and rounded; base
line evenly curved, surface with strong, uneven, concentric
sculpture ; epidermis, brownish or blackish, rayless; left valve
with a strong, triangular pseudocardinal, often with a rudi-
mentary tooth above it and another behind it, with one heavy,
club-shaped lateral; right valve with two strong pseudocardi-

UNIO 603

nals and two short laterals, with a vestige of a third above

them; dorsal scars numerous, placed in a long row under the

pseudocardinals; beak cavities not deep; muscle scars large,
deep; pallial line deep, crenate; nacre silvery, salmon, light or
deep purple, thicker in front, obliquely ridged and grooved.

Length 131, height 88, diam. 32 mm.

Length 135, height go, diam. 33 mm.

Length 121, height 77, diam. 28 mm.

Mexico; Central America.

Unio discus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 74, pl. xvi,
fig. 57; Obs. II, 1838, p. 74, pl. xvi, fig. 57—HAnNLey,
3iv. Shells, 1843, p. 197, pl. xxu, fig. 12—Cuenu, II.
Conch., 1858, pl. xix, figs. 6, 6a, 6b—Stmpson, Syn., 1900,
Pp. 705.

Margaron (Unio) discus Lea, Syn., 1852, p. 31; 1870, p. 50.

Lampsilis discus Pitsery, Pr. Ac. Nat. Sci. Phila., 1909, p. 533-

Umio discus var. connectans von Martens, Biol. Cent. Amer.,
Moll., 1900, p. 510.

Unio panucoensis VoN DEM BuscH in Philippi, Abbild. und
Besch., I, 1843, p. 75. pl. u.-—Kuster, Conch. Cab. Unio,
1861, pl. LXxxt, fig. 1.

Unio discus var. panucoensis VON Martens, Biol. Cent. Amer.,
Moll., 1900. p. 510, pl. xxxu1, figs. 2, 2b.

Unio mexicanus Sowerby, Conch. Icon., XVI, 1867, pl. Lv,
fig. 281.

Unio lapidosus KovELt, Nach. Deuts. Mal. Ges., 1893, p. 151;
Jcon., new ed., VI, 1893. p. 90, pl. cLxxvt, fig. 1120.—Simp-
son, Syn., 1900, p. 700.—von Martens, Biol. Cent. Amer.,
Moll., 1900, pp. 511, 651.

A magnificent, ponderous species, which does not seem to be
very nearly related to anything else, though it has many of
the characters of the gibbosus group. von Martens in the
Biologia Centrali Americana, Mollusca, Supplement, page 651,
states that he has examined the type of Unio lapidosus in the
Berlin Museum said to come from the Euphrates River, and
that he feels sure that it belongs to this species. The figure
of the teeth and muscle scars and a part of the description of

6O4 UNIO

lapidosus in the New Edition of Rossmassler do not agree
with the several speciments of discus I have examined, and
the latter is somewhat more compressed than the measurements
given for lapidosus, yet I feel sure that von Martens is right.
The U. lapidosus differs totally from any form found in the
Paleerctic region or for' that matter in the Old World, and
I felt a good deal of doubt concerning this remarkable in-
truder into the circummediterranean region. But I confess
that it had not occurred to me that it might be U. discus until
I read von Martens’ statement.

Group of Unio sloatianus.

Shell rhomboid, solid, inflated, with a well-defined posterior
ridge and a smaller, fainter one above, making the posterior
of the shell distinctly biangulate, nearly straight or slightly
incurved on the base, rounded in front ; beaks only slightly ele-
vated ; beak sculpture not observed; surface of the valves cov-
ered with somewhat radiately plicate, nodulous corrugations,
which become less pronounced in front; posterior slope radi-
ally plicate; epidermis dark; pseudocardinals stumpy, radial,
granularly striate; laterals double in the left valve, single in
the right, with a faint, secondary ridge below ; anterior muscle
scars deep, nearly smooth ; cavity of the beaks moderate, slight-
ly compressed.

Animal unknown.

UNIO SLOATIANUS (l,ea).

Shell subrhomboid, somewhat inflated, solid, inequilateral,
apparently with rather full, elevated beaks; posterior ridge
high, angled, becoming double midway down, and ending at
the posterior basal part of the shell in a biangulation ; anterior
end a little narrowed and rounded; base line straight; poste-
rior slope obliquely truncated ;surface mostly covered with sub-
radiating, corrugated ridges. Those on the disk are almost
vertical and show a tendency to break into nodules; those on
the posterior ridge and dorsal slope are Strong and almost

UNIO 605

horizontal or slightly up-curved; epidermis thick, chestnut to

blackish; left valve with two strong, rough pseudocardinals

and two laterals; right valve with one pseudocardinal, a ves-
tigial one above it and sometimes traces of a third behind, with
one granular lateral, which often shows vertical striation ;
beak cavities shallow, with a few scars; anterior cicatrices deep
and smooth; nacre whitish-violet or bronzy-tinted, iridescent
behind.

Length 120, height 75, diam. 46 mm.

Chattahoochee and Flint rivers, Georgia.

Type locality, Chattahoochee River, Ga.

Unio sloatianus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr.
Ame Phils See, VET, 1842, p. 217; ple xvi, fig: 33; Obs., IT,
1842, p. 55, pl. xvi, fig. 33—CuHeENu, Ill. Conch. 1858, pl.
XXxII, figs. 7, 7a, 7b.—KustTER, Conch. Cab., 1862, p. 286,
pl. xevr, fig. 3—SIMPson, Syn., 1900, p. 705.

Margaron (Unio) sloatianus Lea, Syn., 1852, p. 21; 1870, p.
aE:

Plectomerus sloatianus Conrap, Pr. Ac. N. Sci. Phila., VI,
195 3;0p) 201.

Unio atromarginatus Lea, Pr. Am. Phil. Soc., I, 1840, p. 288;
eer. Ihe soc. Vv lil, 1642) p, 207, pi. xiii, fig. 21; Obs.
III, 1842, p. 45, pl. x1, fig. 21.—CneEnu, Ill. Conch., 1858,
pl. xxvii, figs. 6, 6a, 6b.—Kuster, Conch. Cab. Unio, 1861,
Pe 250, PlLaLeXxiv, fio. 2.

Margaron (Unio) atromarginatus Lia, Syn., 1852, p. 19; 1870,
Pp. 20.

Plectomerus atromarginatus ConraAp, Pr. Ac. N. Sci. Phila.
WI. 1853; p.260.

Umio aratus Conran, Ann. and Mag., IV, 1849, p. 302.

Unio plectophorus Conrap, Jl. Ac. N. Sci. Phila., I, 1850, p.
277 pl SRRVIL, fig. :7:

Plectomerus plectophorus Conran, Pr. Ac. N. Sci., Phila., VI,
Te53, p. 2.

A fine, robust shell, which superficially resembled the Unio
trapezoides of Lea, but which, I am convinced, is not closely
related to it. The external sculpture of the two is really quite

606 UNIO

different, that of trapesoides though nodulous in an early stage
becomes obliquely plicate on the disk as the shell approaches
maturity, while that of sloatienws is much finer and nearly ver-
tical. The beak cavities of the latter are much shallower than
those of trapezoides and it lacks the scars in the cavities of
the shell, and finally the anterior scars of the latter are very
rough while those of sloatianus are smooth. A little attention
to these characters will enable any one to separate the two
species without difficulty.

Lea’s type of sloatianus is an old, arcuate shell, while the
type of atromargimatus is young and quite different looking.
But the young plicate atromarginatus gradually changes into
the smoother sloatianus as it grows older, and specimens of
both show the dark bordered nacre, though it is more pro-
nounced in the young shells.

Group of Unio crassidens.

Shell generally solid, rather inflated, rhomboid oval, with a
sharp, well-developed posterior ridge; beaks prominent, the
sculpture consisting of a few coarse ridges running nearly
parallel with the growth lines, and swollen at the posterior
ridge; surface of the valves nearly smooth or only marked
by growth lines; posterior slope bearing wrinkled, corrugate,
radiate ridges; epidermis often faintly rayed.

Animal having the branchize very large, rounded below,
inner the larger, free nearly or quite their entire length from
the abdominal sac; branchial and anal openings large, with

many small papille; marsupium occupying the entire outer
gills.

UNIO CRASSIDENS Lamarck.

Shell ponderous, convex or subinflated, subrhomboid, inequi-
lateral; beaks full and elevated, their sculpture a few coarse
ridges running nearly parallel with the growth lines; posterior
ridge well developed and angled, sometimes faintly double
below and ending behind at the base of the shell usually in a
biangulation : base line straight or incurved in old specimens;

UNIO 607

outline of posterior slope subtruncate, slightly curved; surface

with rude, irregular growth lines; posterior slope often having

a few wrinkles; epidermis thick, reddish-brown or chestnut ;

left valve with two strong, rough pseudocardinals and two

heavy laterals: right valve with one strong pseudocardinal
with a small tooth in front of and behind it, with one very
solid lateral ; beak cavities very shallow with a few small scars ;
muscle scars small and deep; pallial line impressed, crenate ;
nacre purplish or salmon.

Length 120, height 79, diam. 50 mm.

Length 93, height 6&8, diam. 40 mm.

Length 128, height 75, diam. 44 mm.

Mississippi drainage generally; Alabama and Tombigbee
rivers ; southeast to the Chattahoochee River.

Type locality, Mississippi and other rivers and lakes.

Unio crassidens LAMARCK, An. sans Vert., VI, 1819, p. 71.—
HANLEY, Biv. Shells, 1843, p. 184, pl. xx, fig. 46—CAaLL, Tr.
Ac. Sci. St. Louis, VII, 1895, p. 12, pl. 11.—Simpson, Syn.,
1900, p. 706.—WaAGNER, Naut., XVIII, 1905, p. 97, pl. vu.

Margarita (Unio) crassidens Lea, Syn., 1836, p. 19; 1838, p.
ied

Margaron (Unio) crassidens Les, Syn., 1852, p. 24; 1870, p.
37:

Elliptio crassidens ORTMANN, Ann. Car. Mus., VIII, 1912, p.
266, figs. 10. Toa.

?Umo nigra RAFINESQUE, Ann. Gen. Sci. Brux., V, 1820, p.
Ole Pl L x, Mos, THA:

Unio niger Say, Am. Conch., VI. 1834.—Conrap, Monog.,
VI. 1836, p. 49, pl. xxv1.—Kuster, Conch. Cab. Unio, 1852,
p. 25, pl. 1v, fig. 1.—Sowerrsy, Conch. Icon., XVI, 1868, pl.
LXXvilt, fig. 408.

?Unio cuneatus BARNES, Am. Jl. Sci., VI, 1823, p. 263.—H11-
DRETH, Am, Jl. Scie XIV, 1828, p: 279, fig. -3:

Mya cuneata Faton, Zool. Text Book, 1826, p. 220.

Unio discus Sowrrey, Conch. Icon., XVI, 1868, pl. Lx, fig.
310.

Unio crassus SowERny, Conch. Icon., XVI, 1868, pl. xcv, fig.
520.

608 UNIO

Var. incrassatus Lea.

Shell smaller, more rhomboid or quadrate than the type,
wrinkled behind the posterior ridge and sometimes having
subvertical corrugations on the disks. It is rather smoother
than typical crassidens.

iength 56, height 36, diam. 23 mm.

Coosa River system; Chattahoochee and rivers of north
Florida; east to Savannah ?

Type locality, Chattahoochee River, Columbus, Ga.

Unio mcrassatus Lea, Pr. Am. Phil. Soc., I, 1840,.p. 286; Tr.
Am. Phil. Soc; Vill, 1840; pe2i7, pl Xvi, tessa Oss
ITT, 1842, p. 55, pl. xvi, fig. 34.—Cuenu, Ill. Conch., 1858,
pl. xxx, figs. 5, 5a, 5).—Kuster, Conch. Cab. Unio, 1861,
p. 192, pl. Lx, fig. 5—Rerve, Conch. Icon., XVI, 1865, pl.
XXVI, fig. 127,—SIMPSON, Syn., 1900, p. 707:

Margaron (Unio) incrassatus Lea, Syn., 1852, p. 24; 1870, p.
37:

Usually considered as a valid species, but recent careful study
and comparison of a large series of material has inclined me
to place it as a variety under crassidens. A considerable
number of intermediate specimens from the Tennessee and
Coosa rivers seem to connect the two completely.

Unio poLtyMorpuus B. H. Wright.

Shell solid, convex to subinflated, generally more or less
rhomboid, inequilateral ; beaks rather full, moderately elevated,
their sculpture not observed; posterior ridge high and sharp,
usually somewhat double below, ending in a point or biangula-
tion at or near the base line; base line straight or slightly
curved; rarely incurved in old shells; surface with irregular
growth lines, wrinkled on the dorsal slope; epidermis thick,
bronzy-green and rayed in the young, reddish-brown to black-
ish in adult shells; left valve with two stout, ragged pseudo-
cardinals and two laterals; right valve with one pseudocardinal
and a small tooth above it, with one, often somewhat double,

UNIO 609

lateral; beak cavities rather shallow; muscle scars impressed ;
nacre white, yellowish, salmon or purple, thicker in front.

Length 96, height 55, diam. 38 mm.

Length 83, height 53, diam. 37 mm.

Type locality, Spanish Creek, Charlton County, Georgia.
Unio polymorphus B. H. Wricut, Naut., XIII, 1899, p. 42.—

SIMPSON, Syn., 1900, p. 707.

A large number of specimens of this form from the type
locality are before me and [| hardly know what to do with
them. ‘The species, if species it is, seems to stand between
crassidens and forbesianus in a different way from what i-
crassatus does. It has the form of forbesianus to some extent,
but is solider and’has a different epidermis. It resembles
crassidens in its solidity and the comparatively shallow beak
cavities. It is very likely a variety of forbesianus.

UNIO FORBESIANUS Lea.

Shell subrhomboid, scarcely inflated, inequilateral, subsolid ;
beaks full and rather high, their sculpture consisting of strong,
slightly corrugated ridges that run nearly parallel with the
growth lines; posterior ridge high, angled, often narrowly
and feebly double below, ending behind in a point or slight
biangulation at or near the base of the shell; base line straight
or curved a little; surface rather smooth, but having sub-
radial plications on the posterior slope; epidermis yellowish
to olive-green and usually rayed in the young shell, tawny or
burnt brown and almost or quite rayless in the adult stage,
nearly smooth, sometimes shining; left valve with two tri-
angular, rough pseudocardinals and two curved laterals; right
valve with one pseudocardina!, sometimes with a vestigial one
above it and one lateral ; beak cavities deeper than in U. crassi-
dens; muscle scars well impressed: nacre white, biuish, cream,
salmon or purplish.

Length &0, height 49, diam. 31 mm.

Length 74, height 39, diam. 25 mm.

Tength 63, height 40, diam. 23 mm.

610 UNIO

Streams from the Congaree River, South Carolina, south
to northern Florida.

Type locality, Savannah River, Ga.

Unio forbesianus Lea, Pro Amt Phil Soc, V7, 1552... 255.
Ee Aan Phily Soci, Xe 18525 ps 204, pli xvi tie 175. Ose
1852, p. 20, pl. xvi, fig. 17—Kuster, Conch. Cab. . Unio,
1861. p. 310, pl. Lxrx, fig. 6—Musecrave, Phot. Conch.,
1863, pl: 11, fig. 2—SOwERBY eats leon, XVI; 1868: pk
LXXI, fig. 361.—SIMPSON, Pr. USs:eNat Mus., XV 192;
DAATO; Pls. XLIX) Nos 3 uy hese2ese st {QO00}p- 70%:

Margaron (Unio) forbesianus LEA, Syn., 1852, p. 24; 1870, p.
37:

Unio moussonianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 268,
pl. xvilighic. 223+ Obse Vs, 1852, ps 24, ple va leek 22.

Margaron (Unio) moussonianus tee SYN. 1852, p. 20,1870;
p. 46.

Ume corvus Lea, Pr. Ac. N. Sci. Phila., T1, 1859; p. 1125, Jl.
Acad. N. Set. Philas, 1Vs1850;pe2r7% al SVIL, fs. O75 Obs.,
VII, 1850, p. 35, pl. xxvit, fig. 97—Sowersy, Conch. Icon.,

JX VAGSI868 pl, Tacx yi ie ie

Margaron (Unio) corvus Lea, 1870, p. 37.

Unio vestitus Lua, Pr. Ac. N. Sci. Phila., V, 1861, p. 393; JI.
Ac. N: Sen Phila; V,91862;\p; 180 pl=xxv, fie 250 - Obs.
LX¢a8624p. Ti, pl: xxvcnss 250:

Margaron (Unio) vestitus Lea, Syn., 1870, p. 50.

It is difficult to draw up any description, which will prop-
erly cover and yet separate from other forms this and most
of the allied species of the crassidens group of Unios. Ina
general way the shells of this species are thinner and smoother
than those of incrassatus and have deeper beak cavities, but
many intermediates are found. which more or less connect not
only these two, but this with other so-called species. Indeed
the group is one of the most difficult to treat of American
Unios. U. moussonianus, U. corvus and U. westitus of Lea
do not seem to me to possess any claims to distinction.

UNIO 611

Unio DANtErst B. H. Wright.

Shell very solid, subinflated to inflated, inequilateral, sub-
rhomboid; beaks full and high, their sculpture not observed;
posterior ridge very full, sharp, becoming double below, be-
hind which the posterior area is often abruptly truncated ; sur-
face covered with rather wide growth lines and a thick, black
epidermis, the posterior slope strongly plicate and rough; left
valve with two triangular, rough pseudocardinals and two
strong, curved laterals; right valve with one pseudocardinal,
often with a small one above, and one lateral; beak cavities
shallow ; muscle scars small and deep; nacre whitish, purplish
or salmon, thicker in front.

Tiength 80, height 51, diam. 34 mm.

Length &o, height 62, diam. 46 mm.

Type locality, Spring Creek, Decatur County, Georgia. Also,
Escambia River, Florida.

Unio danielsti B. H. Wricut, Naut., XIII, 1899, p. 31.—SiMp-

SON, Syn., 1900, p. 708.

This seems to bear about the same relation to U. mcrassatus
that polymorphus does to forbestanus. It is a very solid, quite
inflated form, decidedly truncated behind the posterior ridge
and has a thick, black epidermis.

UNIO PUSILLUS Lea.

Shell subrhomboid, convex to subinflated, rather thin to sub-
solid, inequilateral, with moderately full, but not high, beaks,
their sculpture not observed; posterior ridge high and angled,
often becoming double below, ending in a point or biangulation
near the base of the shell; surface rather smooth ; dorsal slope
having subradial wrinkles; epidermis dirty greenish-yellow,
often feebly rayed; left valve with two subcompressed pseudo-
cardinals and two rather delicate laterals ; right valve with one
pseudocardinal, often with a second small one above it and
one lateral; beak cavities shallow; muscle scars slightly im-
pressed; nacre dull, bluish, purplish or lurid brownish.

Length 58, height 34, diam. 22 mm.

Length 43, height 26, diam. 16 mm.

612 UNIO

Abbeville district, South Carolina; south to northern Flor-
ida.

Type localitv, Ogeechee River, Ga.

Unio pusillus Lea, Pr. Ac. N. Sci. Phila., I, 1840, p. 286; Tx.
Am: Phil. Soc.; VIII, 1842, p. 220, pl. xvii, he. 46; Obes
IIT, 1842, p. 58, pl. xvii, fig. 36.—CuHeENu, Ill. Conch., 1858,
pl. xxxu, figs. 5, 5a, 5>—Kuster, Conch. Cab., 1861, p.
197, pl. Lx1, figs. 3, 4.—Simpson, Pr. U. S. Nat. Mus., XV,
1892; pi ALI, plow figs. 26; Syus, tese; a Zes:

Margaron (Unio) pusillus Laa, Syn., 1852, p. 31; 1870, p. 48.

Unio buxeus Lea, Tr. Am. Phil. Soc., X, 1852, p. 261, pl. xv,
he. /13>-Obs., V, 1852. ps 17, ple av, fe. ae

Margaron (Unio) buxeus Lea, Syn., 1852, p. 29; 1870, p. 46.

Unio anthony Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 41; Jl.
Ac. N. Sci. Phila., V, 1862, p. 197, pl. xxvus, fig. 266; Obs.,
TX, 1863, p. 19; pl. xxvir, fie. 266.

Margaren (Umo) anthonyi Lra, Syn., 1870, p. 43.

More inflated and smaller than U. congareus, more elon-
gated than U. masoni. It is close to U. merus and may be only
a form of it. In pusillus the greatest degree of inflation is at.
the posterior ridge and in front of it the shell is somewhat
wedge-shaped and it is not a very solid species. In merus a
dorsal view shows the shell to be exactly doubly convex and
it is rather a solid shell.

UnIo MERUS Lea.

Shell small, rhomboid, convex, rather solid, somewhat in-

equilateral; beaks full, slightly elevated, their sculpture a
few strong ridges, the lower ones almost doubly looped, the
upper ones curved sharply up behind; posterior ridge full,
angled, single, ending behind at the base of the shell; base line
nearly straight; posterior end decidedly and obliquely trun-
cated ; surface nearly smooth ; epidermis greenish-yellow, faint-
ly raved; left valve with two subcompressed pseudocardinals

and two delicate laterals; right valve with one pseudocardinal:

UNIO 613

and one lateral; beak cavities moderate; muscle scars small,

shallow ; nacre creamy white, thicker in front.

Length 39, height 24, diam. 15 mm.

South Carolina.

Type locality, Abbeville District, S. C.

Unio merus Lea, Tr. Am. Phil. Soc., X, 1852, p. 260, pl. xv,
fig. 10; Obs., V, 1852, p. 16, pl. xv, fig. 10—Srmpson, Syn.,
1900, p. 708.

Margaron (Unio) merus Lea, Syn., 1870, p. 54.

Unio castus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 306; JI.
HEN. set Phila, TV; 1860,-p. 340, pl..ivil, fig. 1745°Obs.,
VIII, 1860, p. 31, pl. wit, fig. 174.

Margaron (Unio) castus Lea, Syn., 1870, p. 40.

Close to forms of pusillus and perhaps only a variety of it.
The posterior ridge is single in all the shells I have seen; it is
heavier and more distinctly rhomboid than that species. The
posterior slope is without wrinkles in all the examples I have
seen, and is very feebly radially furrowed.

Unio mMasont Conrad.

Shell small, somewhat rhomboid, though rounded above, in
front and below, slightly inequilateral, subcompressed ; beaks
moderately full but not much elevated, their sculpture not
known; posterior ridge well developed, angled, ending behind
just above the base ; epidermis olive, clouded with brown, shin-
ing; pseudocardinals prominent, compressed, oblique; beak
cavities capacious ; nacre bluish-white.

Length of the figure 26, height 20 mm.

Type locality, Savannah River, Augusta, Ga.

Unio masoni Conrap, New F. W. Shells, 1834, p. 34, pl. v,
fig. 2; Monog., III, 1836, p. 28, pl. xu, fig. 2—HAN Ley, Biv.
Shells, 1843, p. 201, pl. xxi, fig. 18.—CHENU, Bib. Conch.,
tst ser., IIT, 1845, p. 18, pl. u, fig. 1—Kuster, Conch. Cab.
Unio, 1852, p. 34, pl. v, fig. 6—SIMPSON, Syn., 1900, p. 709.

Margarita (Unio) masoni Lea, Syn., 1836, p. 33; 1838, p. 23-

‘Margaron (Unio) masoni Lea, Syn., 1852, p- 34: 1870, p. 55.

614 UNIO

| have never seen anything, which I could refer to this spe-
cies and am a little in doubt as to its systematic position.
Conrad states that he found it in company with great num-
bers of U. congareus in the Savannah River, at Augusta, and
that it perhaps has more affinity with that than any other spe-
cies. It is shorter and more rounded than U. merus or any of
the forms of the crassidens group. If it were not that it is
said to come from the Savannah River | should think it might
be one of the Pleurobemas, and I am not sure but that it is.
UNIO FRATERNUS Lea.

Shell somewhat elongated, subsolid, subrhomboid, com-
pressed or subcompressed, inequilateral ; beaks apparently not
full or high, much eroded in the only shells examined ; poste-
rior ridge well developed, angled, single above, faintly double
below, ending near the base in a narrow, ill-defined biangula-
tion; surface with feeble growth lines, strongly, radiately
wrinkled on the dorsal slope; epidermis dark reddish-brown,
scarcely lamellosely wrinkled, subshining ; left valve with two
low, stumpy pseudocardinals, and two remote laterals; right
valve with one pseudocardinal and one lateral; beak cavities
shallow, with a row of dorsal scars just at the lower side of
the hinge plate; muscle scars shallow; nacre purplish-white, a
little thicker in front.

Length 65, height 37, diam. 19 mm.

Length 60, height 32, diam. 15 mm.

Type locality, Abbeville District, South Carolina.
Umo.fraternus. Lea, Vr. Am, Phill Sec, 1852, p.. 26s) pl:

XVI, fig. 15; Obs:, V;, 1852, p. 10,epl. xvi, fies 15 Kose,

Conch. Cab. Unio, 1861, p. 201, pl. Lxvi, fig. 2—SrImpson,

Syn, 19G0,,\p., 700.

Margaron (Unio) fraternus Les, Syn., 1852, p. 32; 1870, p.

51.

\ somewhat elongated, compressed shell, with reddish-
brown epidermis and purplish nacre. It is more compressed
and darker colored than U. congareus, to which it seems near-
ly allied and its pseudocardinals are more stumpy. Dr. Lea has

UNIO 615

shells in his collection labeled Unio fraternus from the Chat-

tahoochee River that I am inclined to believe are not that

species.

Unio CONGAR4US Lea.

Shell rhomboid, subcompressed, rather thin to subsolid,
somewhat inequilateral ; beaks moderately full and slightly ele-
vated ; their sculpture consisting of parallel undulations ; pos-
terior ridge high, and angled, double below, the greatest diam-
eter of the shell being along its line; in front of it the shell
is wedge-shaped; basal line nearly straight; posterior end
obliquely truncated above, somewhat biangulate below; sur-
face with irregular growth lines, wrinkled on the dorsal slope ;
epidermis dirty greenish-yellow or tawny, generally rayed, es-
pecially in young shells, scarcely shining; left valve with two
ragged, subcompressed pseudocardinals and two delicate lat-
erals; right valve with two pseudocardinals, the upper small,
and one lateral; beak cavities not deep; muscle scars super-
ficial; nacre purplish, often lurid in the shell cavities

Length 81, height 48, diam. 25 mm.

Length 62, height 34, diam. 19 mm.

Cape Fear River. North Carolina; south to Savannah, Ca.

Type locality, Congaree River, S. C.

Unio congareus Les, Tr. Am. Phil Soc., TV, 1831, p. 72, pl.
VI, fig. 4; Obs., I, 1834, p. 82, p!. v1, fig. 4.—Conrap, Monog.,
III, 1836, p. 27, pl. x11, fig. 1—Han ey, Biv. Shells, 1843,
p. 200, pl. xxu1, fig. 31-—CuENu, Ill. Conch.,-1858, pl. 111,
figs. 5, 5a, 50.—Sowersy. Conch. Icon., XVI, 1867, pl. Lx,
fig. 296.—SIMPSON, Syn., 1900, p. 709.

Margarita (Unio) congareus Lea, Syn., 1836, p. 32; 1838, p.
22.

Margaron (Unio) congareus Lia, Syn., 1852, p. 33; 1870, p.
54-

Unio fulvus Lea, Tr. Am. Phil. Soc., V, p. 96, pl. x11, fig. 39;
Obs., I, 1834, p. 208, pl. x1it, fig. 39.—HaANtey,. Biv. Shells,
1843, p. 200, ol. xxi, fig. 32—-SowrRBy, Conch. Icon.,
XVI, 1858, pl. txxx1x, fig. 483.

616 UNIO

Margarita (Unio) fulvus Lra, Syn., 1836, p. 32; 1838, p. 22.
Margaron (Unio) fulvus Lea, Syn., 1852, p. 33; 1870, p. 54.

The type is a voung shell and is close to U. pusillus, in fact
Dr. Lea has one lot of shells from Rock River, North Carolina,
labeled U. congareus that I am inclined to believe is pusillus.
The adult shells are larger and more compressed than any I
have seen of the latter species.

UNIO DARIENSIS Lea.

Shell large. subrhomboid or subtrapezoidal, convex to in-
flated, subsolid to solid, :nequilateral ; beaks moderately full to
inflated, somewhat elevated, their sculpture not seen; posterior
ridge high and sharply angled, becoming double below and
ending behind near the base in a biangulation; dorsal slope
often wrinkled, obliquely truncated; anterior end narrowed
and rounded; surface with rude concentric growth lines; epi-
dermis olive-green and faintly rayed in young shells, becoming
reddish-brown or blackish in old shells; left valve with two
ragged, stumpy pseudocardinals and two granular laterals;
right valve with one pseudocardinal, sometimes with a feeble
second one above it, and one lateral; the laterals show traces
of vertical striation; muscle scars well marked; beak cavities
shallow to moderately deep; nacre white to purple, a little
thicker in front.

Length 125, height 76, diam. 42 mm.

Length 125, height 65, diam. 33 mm.

Length 117, height 68. diam. 48 mm.

Southeast Georgia to north Florida.

Type locality, New Darien, Ga.

Unio dariensis Lea, Tr. Am. Phil. Soc., VIII, 1842, p. 246, pl.
xxvi, fig. 61; Obs., III, 1842, p. 84, pl. xxv1, fig. 61.—CHE-
nu, Ill. Conch., 1858, pl. xxxin, figs. 6, 6a, 6b.—SoweErsy,
Conch. Jcon., XVI, 1868, pl. xcr, fig. 494.—Stmpson, Pr. U.
S. Nat, Mins... 1892) px 4a ple ian, see eine oe
Syn., 1900, p. 716.

Marearen (Unio) dariensis Lea, Syn., 1852, p. 33; 1870, p. 54.

UNIO 617

A most variable species, which has close relationships with
the complanatus group. The disk is often sculptured with
subvertical furrows and it is occasionally subnodulous. Some
of the compressed specimens approach U. roanokensis, but are
rougher and have a more distinct posterior ridge. The type
is a young shell.

UNIO MONROENSIS Lea.

Shell subrhomboid, convex or subinflated, subsolid, inequi-
lateral; beaks rather full and elevated, their sculpture appar-
ently a few corrugated, longitudinal ridges; posterior ridge
well developed, angled, ending behind in a point near the base ;
base line curved; post-dorsal area obliquely subtruncated ; an-
terior end round; surface nearly smooth, the dorsal slope
sometimes having a few wrinkles; epidermis reddish or olive-
brown, darker behind; left valve with two small, ragged, sub-
compressed pseudocardinals and two delicate, curved laterals ;
right valve with one or two pseudocardinals, the upper, when
present, always small, and one lateral; muscle scars rather
shallow ; nacre brilliant, purplish or violet, iridescent behind.

Length 70, height 43, diam. 25 mm.

Florida.

Type locality, Lake Monroe, Fla.

Unio monroensis Lesa, Desc. of 12 sp. of Uniones, 1843, no
pasination: “ir. Am. Phil. Soc. EX; 1845?; p. 270, pl. Xxt,
fig. 8; Obs., IV, 1848, p. 37, pl. xu, fig. 8—Simpson, Pr.
U2. Natoiiuss XV 21892,.p. Ate; pl. Li; fig. 1; Syn., 1900,
p. 710.

Margaron (Unio) monroensis Lea, Syn., 1852, p. 29; 1870, p.
40.

Lea has only a single specimen, the type, in his collection and
it differs a little from anything else | have seen. The posterior
ridge curves up in the middle while in other shells, which seem
to be this, it curves down medially. There seems to be an
almost absolute transition from this species to U. hartwrighti
and U/. hinklevyi.

618 UNIO

Unio HAR?wrRIGHTI B. H. Wright.

Shell subrhomboid, subinflated, subsolid, inequilateral, with
full, high beaks, whose sculpture has not been observed; pos-
terior ridge high, pinched up above almost into a carina, be-
coming almost double below and ending in a point just above
the base; post-dorsal slope obliquely truncated above, some-
what biangulate below; surface nearly smooth, with a few
low, concentric ridges, decidedly wrinkled on the dorsal slope:
epidermis rich, reddish-brown, faintly rayed; left valve with
two subcompressed pseudocardinals and two remote laterals;
right valve with one pseudocardinal and one lateral; nacre
brilliant, salmon in the cavity, tinted purple at the border, iri--
descent behind.

Length 79, height 45. diam. 30 mm.

Type locality, Lake Beresford, Florida.

Unio hartwrightt B. HO. Wricut, Naut., 1X, 1896, p. 121, pl..

11, figs. .4-6.—SIMPSON, Syn., 1900, p. 710.

The only specimen, which IT have seen, is the type and this
has a remarkably high, almost pinched up, posterior ridge, de-
cided wrinkles behind and rich colored epidermis and nacre.
Unio HINKLEY! B. H. Wright.

Shell long rhomboid, inequilateral, subinflated, scarcely sub-
solid; beaks moderately full, slightly elevated, their sculpture
not seen; posterior ridge well developed, angled, ending be-
hind in a point at or near the base of the shell; dorsal slope
very faintly wrinkled, obliquely truncated; anterior end cut
away a little below, rounded; base line straight or slightly
curved; surface nearly smooth; epidermis dark green, shaded
brown and almost black behind; left valve with two compress-
ed, reflexed pseudocardinals and two delicate laterals; right
valve with one pseudocardinal and one lateral; muscle scars
shallow ; nacre rather bright, purplish, iridescent behind.

Length 74, height 38, diam. 23 mm.

Florida.

Type locality, Lake Monroe, Fla.

UNIO 619

Unio hinkleyt B. H. Wright, Pr. Ac. N. Sci. Phila., 1888, p.
p. 117, pl. iv, fig. 3—Simpson, Pr. U. S. Nat. Mus., XV,
T8902, ).422.-pl, EX, 1. 45 Syn., 1900, p. 7.10.

I have before me what is said to be the type from Mr. B. H.
Wright, but, if it is, the figure is not correctly drawn. The
shell is more pointed behind and straighter on the base than
the figure shows. ‘The species, if species it is, would go in the
buckleyi group as well as in this.

JNIO WEBSTERI B. H. Wright.

Shell somewhat elongated, subrhomboid, convex, rather thin,
inequilateral; beaks only moderately full and elevated: pos-
terior ridge angled, becoming almost double below, ending in a
rounded point or biangulation a little above the base ; basal and
dorsal lines somewhat rounded; surface with irregular
growth lines sometimes wrinkled behind; epidermis reddish-
brown to blackish, somewhat rayed in young shells; left valve
with two compressed or subcompressed pseudocardinals and
two remote laterals; right valve with one pseudocardinal and
one lateral; muscle scars shallow; nacre bluish to purplish.

Length 97, height 55, diam. 32 mm.

Florida.

Type locality, Lake Woodruff, Volusia Co., Fla.

Unio websteri B. H. Wricit, Pr. Ac. N. Sci. Phila., 1888, p.

113, pl. 11, fig. 2—Srimpson, Syn., 1900, p. 7II.

A very unsatisfactory species, if it is a species. Mr. Wright
has sent three examples to the National Museum, which he
claims are typical, but neither of them agree very closely with
his figure. The two younger shells are rayed, they are differ-
ently shaped from the older one and have heavier pseudocar-
dinals. I confess I am at a loss to know what to do with it.

UNIO porsAtus Lea.

Shell subrhomboid or sometimes almost subtriangular, in-
equilateral, convex, subsolid; beaks somewhat elevated but not
inflated, their sculpture not observed; posterior ridge full, an-
gled above, becoming double below, ending behind near the

620 UNIO

base in a biangulation; anterior end slightly narrowed; pos-

terior slope often wrinkled, obliquely truncated; surface with

irregular growth lines; epidermis dirty, tawny-brown, some-
times feebly rayed: left valve with two ragged, stumpy pseu-
docardinals and two laterals, the lower largest; right valve
with one pseudocardinal, sometimes with a small one above,
and one lateral; muscle scars well marked; nacre lurid, tinted
with purple.

Length 59, height 39, diam. 22 mm.

Type locality, Catawba River, North Carolina. Also, Flor-
ida.

Umio dorsatus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 160;
ji. Ac. N. Ser Phila; VI, 1868; pc 300, pl. xnvitie. 1127 Ops.
XIT, 1860, p. 60, pl. xiv, fig. 112.—Simpson, Pr. U. S. Nat.
Mus., XV, 1892,\p. 411, pleaay fig. 75 11, hes; n; 2 Sy
TQOO, p. ZIT.

Margaron (Unio) dorsatus Lea, Syn., 1870, p. 37.

This species shows relationships with the complanatus group.

Some specimens recall U. congareus, but the shells are shorter,

rougher and rather more narrowed in front.

UNIO WACCAMAWENSIS Lea.

Shell rather elongated, rhomboid, inequilateral, scarcely sub-
solid, subinflated or inflated; beaks not high or full, their
sculpture not seen; posterior ridge very high, decidedly an-
gled, ending behind in a point at or near the base of the shell;
dorsal slope obliquely truncate, the termination joining the dor-
sal line at an angle; surface with delicate growth lines; pos-
terior slope often wrinkled; epidermis ashy or smoky-green.
with radiating wrinkles; left valve with two compressed pseu-
docardinals and two delicate laterals; right valve with one
pseudocardinal and one lateral; nacre bluish-white.

Length 43, height 21, diam. 17 mm.

Length 37, height 18, diam. 15 mm.

Type locality, Waccamaw Lake, North Carolina.

Unio waccamawensis Lea, Pr. Ac. N. Sci. Phila., VII, 1863,
p. 193 [i Ac N. Sci. Philay: Vi;1866, p..lompion, ne. Ee;
Obs., XI, p. 20, pl. v, fig. 14.—Simpson, Syn., 1900, p. 7II.

Margaron (Unio) waccamawensis Lea, Syn., 1870, p. 36.

UNIO 621

An abberrent form, which perhaps might as well go in the
buckleyi group as here. Young shells remind one somewhat
of some of the specimens of Alasmidonta heterodon, but this
form is more inflated and a little differently colored.

Group of Unio pigerrimus.

Shell rather solid, elliptic rhomboid, somewhat inflated, with
a low, rounded posterior ridge, sometimes a little arcuate be-
low, biangulate behind; beaks full, sculpture a few coarse
ridges, which are curved upward and swollen where they cross
the posterior ridge; surface concentrically striate and often
sculptured with curved, subradiating or zigzag corrugations,
which have a tendency to break into nodules ; epidermis brown -
ish; hinge rather heavy; pseudocardinals stumpy, granular :
laterals club-shaped ; muscle scars well marked.

Animal unknown.

UNIO PIGERRIMUS Crosse and Fischer.

Shell inequilateral, subelliptical or subrhomboid, inflated
quite solid, with full high beaks whose sculpture has not been
observed ; posterior ridge rounded, slightly biangulate, ending
in a feeble biangulation behind; the posterior slope obliquely
subtruncate ; surface covered with rude, curved, subradial pli-
cations, which are divaricate on the posterior ridge; epidermis
blackish-olive ; hinge thick ; left valve with two pseudocardinals
the hinder much higher and two laterals; right valve with two
pseudocardinals, the upper small and one lateral ; anterior mus-
cle scars deep, very rough; posterior scars shallow; nacre
white, tinted with rose.

Length 59, height 38, diam. 27 mm.

Mexico.

Unio pigerrimus Crossk and Fiscuer, Jl. de Conch., XLI,
1893, p. 293.—FiscHeR and Crossr, Miss. Sci., IT, 1894, p.
582, pl. Lxv, figs. I, la—Simpson, Syn., 1900, p. 711.

Unio psoricus var. pigerrimus von Martens, Biol. Cent.
Amer., Moll., 1900, p. 494.

622 UNIO

A rather short, solid species with heavy hinge and rude
sculpture. According to its authors the nacre is tinted with
rose, while that of mitchelli is white.

UNIO MITCHELLI Simpson.

Shell subrhomboid, oblong, moderately convex, rather solid,
inequilateral, with rather low, somewhat flattened, beaks,
whose sculpture consists of a few strong, irregular ridges
running nearly parallel to the growth lines; posterior ridge
rather low, generally rounded and sometimes double, often
ending behind in a feeble biangulation; base line straight or
slightly curved, sometimes a little arcuate; surface covered
with irregular, rather feeble, concentric ridges and showing
sometimes on the posterior slope and rarely on the disk a few
faint corrugations; epidermis olive to black, greenish when
young, sometimes faintly rayed on the earlier growth; left
valve with two rather small, but solid, ragged, nearly equal
sized, pseudocardinals and two remote laterals; right valve
with one strong pseudocardinal, sometimes with a small second
one above, and one lateral; beak cavities shallow, showing nu-
merous scars; anterior scars rather shallow, smooth, posterior
scars large, round, impressed; nacre white.

Length 54, height 33, diam. 20 mm.

Length or, height 58, diam. 33 mm.

Southern Texas to New Leon, Mexico.

Type locality, Guadalupe River, Victoria Co., Texas.

Unio mniitchelli Simpson (in Dall.), Pr. -U. S. Nat. Mus.,.

XVILE 1806, p. 5; PryU Se Nat isS Cex 1rSeOne ae

pl. XXX, figs. I-33; Syn, 1000, p.. 7 ET.

Var. thermg: B. H. Wright.

Shell with a more decided posterior ridge than the type;
beak sculpture irregular and broken up, sometimes somewhat
doubly looped; epidermis smoother and more shining than in
typical shells.

Southern Texas.

Type locality, San Saba River, Menard Co., Texas.

UNIO 623

Unio thermgi B. H. Wricut, Naut. XII, 1898; p. 93.—Srmp-
SON, Pr ng och . ila 1900, p. 79, pl. Iv, fig. 5; Syn.,
LQOO; Pp. .7 12.

Var. elongatus n. v.

Shell considerably elongated, biangulate and slightly com-
pressed behind; epidermis rather smooth, greenish-brown ;
beak sculpture irregularly doubly looped.

Length 80, height 43, diam. 24 mm.

Guadalupe River, Kerr County, Texas.

Much longer in proportion to its height than the type or the
variety iieringi!, but having -the same kind of epidermis and
beak sculpture as the latter.

In deference to the opinions of some of our best concholo-
gists | have reduced the form called theringi to the rank of a
variety of mitchell:. Typically the two are quite distinct but
there seem to be many intermediate forms. Unio mitchelli is
apparently close to U. pigerrimus, but from the figures and
description of the latter, it is a shorter, much solider form,
with stronger teeth, and hinge plate, and much more rudely
sculptured surface.

UNIO SPHENORHYNCHUS Fischer and Crosse.

Shell very inequilateral, elongated, arcuate, subinflated, its
greatest diameter being opposite the beaks, from which to a
point one-third of the way from the posterior end there is a
gradual narrowing and from this point to the posterior end
there is a rapid slope, solid; posterior ridge rather well devel-
oped. scarcely double; surface strongly concentrically striate,
and having a few, short, subobsolete, radial plications ; epider-
mis brownish-black ; beaks moderately full, their sculpture not
observed: left valve with two strong pseudocardinals and two
remote curved laterals; right valve with one strong, lacerated
pseudocardinal and a faint tooth above; anterior scars deep
and rough; posterior scars shallow; nacre yellowish in the

624 UNIO

cavity of the shell, whitish or bluish and iridescent at the

border.

Length 71, height 37, diam. 27 mm.

Mexico.:

Unio sphenorhynchus Fiscuer and Crosse, Miss. Sci., LI,
1804, p. 617, pl. LXxvI, figs. 2, 2a—SIMPSON, Syn., 1900,
pei 7ae:

This shell is apparently related to Unio mitchelli, but 1s
longer and more drawn out posteriorly than the type and is
more inflated than the variety elongatus. It differs from all
allied forms in being decidedly arcuate, the base line being de-
cidedly incurved in the shell figured.

Unio RUBICUNDUS von Martens.

Shell oblong, subrhomboid, solid, subinflated with a well
developed posterior ridge, which is scarcely double; beaks
rather high about two-fifths of the way from the anterior end
of the shell, their sculpture not noted; surface rather strongly
concentrically striate or sulcate, and having curved plications
on the posterior slope: posterior end feebly biangulate; post-
dorsal margin curved; base very slightly incurved; epidermis
fuscous ; left valve with two crenulated, strong pseudocardi-
nals and two strongly curved laterals; muscle scars impressed,
the anterior ones rough; pallial line remote from the border
anteriorly ; nacre purple.

Length 80, height 57, diam. 34 mm.

North Guatemala; Coban.

Unio rubicundus von Marrens, Biol. Cent. Am., Moll., 1900,

D514, pl. Xxxiv, figs: 3,36:

Only a single valve of this is known, and I am somewhat
at a loss to say where it groups. I, however, incline to place
it with U. mitchelli and pigerrimus. Its teeth are a good deal
like those of old specimens of mitchelli and the surface is sculp-
tured somewhat after the manner of the two forms I have
placed here. Its widely removed pallial line is a good distinc-
tive character, and in its strong sulcations it differs from any
related form.

UNIO 625

Group of Unio liebmanni.

Shell rather solid, inflated, ovate rhomboid or trapezoidal.
with a well-developed posterior ridge, pointed at or near the
base behind, but not bianguiate, nearly straight or slightly
incurved below ; beaks full, sculpture not seen; surface smooth
or concentrically striate ; epidermis dark, scarcely rayed ; hinge
rather strong; pseudocardinals heavy, compressed; muscle
scars distinct ; nacre livid to whitish.

Animal unknown.

Unio LiGBMANNI Philippi.

Shell rather large, inequilateral, elongated, subelliptical to
subrhomboid, solid, convex, with a moderately developed pos-
terior ridge, which may be rounded or angled; beaks not
greatly elevated, their sculpture not observed; anterior end
rounded and angled above just in front of the lunule; dorsal
margin curved behind the beaks, sometimes feebly biangulate
behind; basal line very slightly rounded, the post-basal point
but little elevated; epidermis dark brown or blackish, sub-
shining; left valve with two ragged, subcompressed pseudo-
cardinals, the hinder reflexed, and two laterals, the upper very
feeble; right valve with one pseudocardinal and sometimes a
faint one above it, with one lateral sometimes slightly doubled ;
beak cavities shallow, showing the dorsal scars; anterior mus-
cle scars deep and somewhat torn; nacre flesh-colored or pur-
ple. thicker in front.

Length 92, height 50, diam. 35 mm.

Mexico.

Umo hebmanni Putiripri, Zeits. fir Mal., IV, 1847, p. 96;
Abbild. und Besch., III, 1849, p. 109, pl. vi, fig. 1—KuSTER,
Conch. Cab. Unio, 1862, p. 281, pl. xciv, fig. 7—Simpson.
Syn., 1900, p. 712.—von Martens, Biol. Cent. Amer., Moll.,
L900; p..500; ph XXxxKIV). figs. Tegay 10:

Margaron (Unio) licbmanni Lra, Syn., 1870, p. 48.

I have only seen a single specimen of this species, a fine
shell from Passo de Orijo, Mexico, presented to the National

626 UNIO

Museum by von Ihering. So closely does this resemble a
large Unio buckleyi that I know of no characters which con-
stantly differ between the two. It is a little wider and more
broadly biangulate behind than most specimens of buckleyi; the
epidermis is a little different from that of that species and the
nacre becomes thin behind a little more suddenly, but occa-
sional specimens of buckleyi show the peculiarities of form,
nacre and epidermis that liebmanni does. I cannot doubt that
it is a Mexican species and it 1s quite probable that a good
series showing difterent stages of growth would furnish good
differential characters.

Unto opacatus Crosse and Fischer.

Shell subrhomboid, solid, inflated, with a high, pronounced,
curved posterior ridge, with full high beaks, whose sculpture
has not been examined; lunule well marked, the epidermal
matter extending through under the beaks; there is a sort of
rounded anterior ridge and in the region of it there are some-
times curved, radial, elevated lines; anterior end rounded;
dorsal line curved from the beaks; base straight or decidedly
incurved, ending in a beak behind; epidermis dark brown or
blackish, somewhat silky, slightly rayed in the young shell;
left valve with two ragged pseudocardinals, which are partly
joined together and two short, curved laterals; right valve
with two pseudocardinals, the upper generally smaller but
sometimes equalling the lower in size, with one lateral and
often a vestigial second; beak cavities rather deep; muscle
scars impressed, the anterior ones very rough; nacre whitish-
salmon or purplish-tinted, dull.

Length 49, height 32, diam. 25 mm.

Length 58, height 36, diam. 29 mm.

Mexico, various localities.

Unio opacatus Crosse and Fiscuer, JI. de Conch., XLI, 1893,
p. 295.—Fiscurr and Crossr, Miss. Sci., 11, 1894, p. 592, pl.
LXVI, figs. I, 1@.—SIMPSON, Syn., 1900, p. 712.

A very solid shell, shaped much like U. plerus Conrad, but
entirely destitute of nodules. It has a slightly developed an-

UNIO 627

terior ridge, which is well rounded, and sometimes has faint,
curved, raised, radial lines in the anterior part of the shell.
which are shown in the figure of Fischer and Crosse though
they do not call attention to the fact. They state that the
pseudocardinals of the right vaive are equal in size, which is
the case in some specimens but not in all. The shell is often
longer in proportion than theirs.

Group of Umio buckley.

Shell oval, obovate, subtrapezoidal, or elliptical, with a more
or less developed posterior ridge, often biangulate behind,
compressed or inflated, thin or somewhat solid ; beaks generally
full, sculptured with several rather strong concentric ridges,
which are either nearly parallel with the growth lines or slight-
ly doubly looped; posterior slope often faintly wrinkled; epi-
dermis usually smooth and shining in the younger shells, often
rough when old, becoming darker with age, rayed when young.
Hinge teeth solid or compressed; nacre mostly brilliant, of
many shades. Animal not differing especially from that of
closely related groups.

UNIO BUCKLEYI Lea.

Shell generally long ovate, rarely subrhomboid or somewhat
obovate, subinflated to inflated, subsolid to solid, inequilateral ;
beaks rather full and high, their sculpture consisting of nu-
merous, slightly doubly-looped ridges; dorsal slope sometimes
carried up, especially in the younger shell, so as to form a
small wing, in which case the general outline is somewhat
rhomboid; posterior ridge usually full and rounded, ending
behind in a blunt point at or below the median line; surface
varying from smooth to somewhat rough; epidermis generally
smooth and shining in the younger shells, often black and
coarse in old ones, tawny, brownish, coppery, greenish-yellow
or olive-green, often beautifully rayed when young; left valve
with two usually subcompressed, ragged pseudocardinals and
two laterals; right valve with two pseudocardinals, the upper

628 UNIO

small, and one lateral; beak cavities shallow; muscle scars im-
pressed; nacre white, straw, yellow, salmon to purple, usually
bright and iridescent behind.

I,ength of type 94, height 50, diam. 36 mm.

Length 72, height 38, diam. 26 mm.

Length 70, height 33, diam. 21 mm.

Length 40, height 27, diam. 18 mm.

Florida.

Type locality, Lake George and Lake Monroe, Fla.

Unio buckleyt Lea, Desc. of 12 Uniones, 1843 (no pagina-
tion); Tr. Amy Phils Soc.; 1X5 1845? p. 276,)pl x xine he:
2; Obs., IV, 1848, p. 34, pl. xxxrx, fig. 2—KustrEr, Conch.
Cab. Unio, 1861, p. 177, pl. ivi, fig. 2—Sowersy, Conch.
Icon., XVI. 1866, pl. xxxiv, fig. 175.—Simpson, Pr. U. S.
Nat..Mus:, XV; 08092; pi.417; pla Lv, figs. O07 Exe hes:
Ty. 2 5 ky fie 2 5 Syms TOOO pals:

Margaron (Unio) buckley Lea, Syn., 1852, p. 30; 1870, p. 48.

Unio buddianus Lea, Desc. of 12 Uniones, 1843; Tr. Am.
Phil. (Soc, IX 18457?) pe 277, plo, ties ; ObseiVe res:
p- 35, pl. xi, fig. 5—Kuster, Conch. Cab. Unio, 1861, p.
249, pl. LXxxIVv, fig. 1—RereEve, Conch. Icon., X VJ, 1865, pl.
xx, fig. 88.

Margaron (Unio) buddianus Lea, Syn., 1852; p. 32; 1870, p.
se

Unio dali B. H. Wricut, Pr. Ac. N. Sci. Phila., 1888, p. 119,
pl Vi, fig: Te
It is difficult to write a description which will cover the

almost infinite variety of forms that I believe should be in-

cluded under the name of buckleyi. Most of the younger shells
are smooth and shining, and are often beautifully though
rather faintly rayed. Usually the epidermis becomes rough
and blackish at maturity or with age, and old specimens are
often arcuate. Under very favorable circumstances the shells
retain their brilliancy when fully mature or even when old.
There is great variation in the degree of solidity of the shell

UNIO 629

and teeth as there is in the nacre. A number of varieties
might be made but most of them so completely mix with the
typical form that it hardly seems worth while to designate
them.

Var. orcutin S. H. Wright.

Shell almost evenly ovate, rather inflated, subsolid or solid:
epidermis smooth and shining, generally bronzy or coppery,
rayed with green; nacre rich and brilliant, frequently golden,
coppery or bronzy, and iridescent.

Length 65, height 39, diam. 26 mm.

Type locality, Myakka Lake and River, Manatee County,
Florida.

The type of this was collected by the writer and sent to Mr.
Wright and it came from the Myakka River or Lake. It is
found in other Floridan localities.

Unio orcuttu S. H. Wricut, West. Am. Sci., IV, 1888, p. 60,

3 figs.

Unio buckleyi var. orcuttii StMPSON, Syn., 1900, p. 713.
Unio JAYENSIS Lea.

Shell rather elongated, subovate or subrhomboid, often being
slightly winged, in which case it assumes the latter form, con-
vex to subinflated, inequilateral, generally rather thin; beaks
only moderately full and elevated, their sculpture consisting
of irregular, corrugated, somewhat doubly-looped ridges; pos-
terior ridge rounded or subangular above, generally double
below. ending behind in a more or less definite biangulation at
or below the median line; surface with uneven growth lines;
epidermis often shining yellowish or yellow-green and rayed
in young shells, greenish-brown or blackish and dull in old
ones; pseudocardinals and laterals delicate; beak cavities shal-

low ; nacre generally purplish, sometimes salmon-tinted, usually
dull.
Type locality, Florida.

630 UNIO

Unio jayensis Lea, Tr. Am. Phil. Soc., VI, 1838, p. 28, pl. rx,
fig. 23; Obs.,. Il, 1838, p. 28, pl. 1x, fig. 23.-—Haniey, Biy,
Shells, 1843, p. 206, pl. xxi, fig. 53.—CHENu, IIl. Conch.,
1858, pl. xxi, figs. 4, 4a, 4b.—Sowersy, Conch. Icon., XVI,
1867, pl. Lx, fig. 301; pl. Lxvu, fig. 343?—Simpson, Syn.,
[QOOs ps 713:

Margarita (Unio) jayensis Lea, Syn., 1836, p. 37; 1838, p. 24.

Margaron (Unio) jayensis Lea, Syn., 1852, p. 37.

Elhiptio jayensis ORTMANN, .Ann. Car. Mus., VIII, 1912, p.
270.

Unio prasinatus Conrap, Am. Jl. Conch., II, 1866, p. 279, pl.
Venn LAR

Margaron (Unio) jayanus Lra, Syn., 1870, p. 60.

Unio javanus B. H. Wricut, Check List, 1888.—Srmpson,
Pro? s. Nate Mus. xX Ve18025p. 4 1Oupl nce teeae

Unio simpsoni B. H. Wricnt, Check List, 1888.

Umo marshu B. H. Wricwt, Pr. Ac. N. Sci. Phila., 1888, p.
PIO A pl. \e ties 2:

Unio tryom B. H. Wricut, Pr. Ac. N. Sci. Phila., 1888, p.
120; splavil, fie. 2:

Generally more elongated, less inflated, thinner and duller
colored within and without than U. buckleyi. But there are
intermediates, which I find very difficult to name and which
might about as well be placed in one species as in the other.

Unto suBLURIDUS Simpson.

Shell rather small, subrhomboid or subelliptical, convex,
solid or subsolid, inequilateral; beaks apparently not full or
high; posterior ridge low, widely rounded or widely, feebly
biangulate ending behind at and below the median line in a
wide rounded point or a biangulation; outline of dorsal slope
obliquely subtruncate, but curved; base line curved, sometimes
full behind the middle; anterior-end narrowed a little, round-
ed; surface nearly smooth; epidermis tawny-brown or pale
reddish-brown, slightly concentrically wrinkled, subshining ;
pseudocardinals subcompressed, two in the left valve and one

UNIO 631

with a faint upper one in the right valve; laterals curved:
muscle scars small: nacre dirty copper-colored, irridescent be-
hind.

Tength 42, height 23, diam. 14 mm.

Type locality, Orange Springs, Marion County, Florida.
Umno subluridus Stmeson, Pr. U. S. Nat. Mus., XV, 1892, p.

AZ2 Dio LXXUL, HES. 34> Synth, TODO; p.-743.

! can not be certain as to the relationship of this species, as
the beaks are eroded in the only shells I have seen. I placed
it in the section Uniomerus in the Synopsis, but am rather in-
clined now to put it near Unio coruscus and buckleyi. One of
the three specimens I have before me is distinctly biangulate
behind. The anterior end is rounded in front, not truncate as
it is in coruscus.

Unto coruscus Gould.

Shell generally oval, sometimes subrhomboid, subinflated
to intlated, subsolid to solid, inequilateral ; beaks moderately
full, somewhat elevated, their sculpture not observed; poste-
rior ridge full, rounded, sometimes imperfectly double below
and ending in a blunt point or slight biangulation at or below
the median line; anterior end usually more or less truncated,
ending in an angle above; dorsal and basal lines curved; sur-
face commonly smooth: epidermis tawny, yellowish-green to
reddish-brown, sometimes clouded or faintly rayed, shining ;
left valve with two compressed to stumpy, ragged pseudo-
cardinals and two curved laterals ; right valve with’one pseudo-
cardinal, often with a second small one above it and one lat-
eral ; beak cavities shallow; muscle scars deep in heavy shells,
shallow in thin ones; nacre purplish, dull or slightly shining,
sometimes iridescent behind. JI,ength of a shell in the Lea col-
lection presented by Dr. Gould, 29, height 17.5, diam. 31 mm.

Length 48, height 24, diam. 17 mm.

Length 7o, height 40, diam. 30 mm.

Florida.

Type locality, River St. John’s, near Lake Beresford, Fla.

632 UNIO

Unio ceruscus GouLp, Pr. Bost. Soc. Nat. Hist., I, 1856, p. 15.
—Simpson, Pr. U. S$. Nat. Mus., XV, 1892, p. 419, pl.
LX, figs. 1, 7.— Syn., 1900, p. 714. Frierson, Naut.,
XXV 10115 p.zo, pl. Tees el eaase

Margaron (Umno) coruscus LEA, Syn., 1870, p. 48.

This is a remarkably variable and puzzling form and inter-
mediates are abundant leading in the direction of several
other species. ‘There is a small shell in the Lea collection
from Dr. Gould with the dimensions given above, which has
no locality but “Florida” given, which may probably be con-
sidered typical. It seems to have the characters of maturity
though it may be a young shell. It is a rather solid, inflated,
oval, shining shell, the epidermis being clouded tawny, green-
ish-yellow and green, with a few faint rays, whence its name
coruscus, no doubt. Nearly all the specimens which I refer to
this species, are more or less truncated in front and angled at
the upper anterior part. The shells are usually solid, rather
inflated and oval in outline, though thinner specimens occur,
and others, which are narrowed in front. The nacre is purplish
in all the numerous specimens I have seen, and it is generally
dull. One or two forms may possibly be worthy of varietal
names.

Var. frvanus B. H. Wright.

Shell not quite so inflated as is usual, subsolid; epidermis
reddish, orange, red-brown and greenish, often finely raved,
very brilliant.

Length 43, height 25, diam. 15 mm.

Type localitv, Lake Ashby, Volusia County, Florida.

Unio fryanus B. H. Wricut, Pr. Ac. N. Sei. Phila., 1888, p:

TIS Ap hehe te

Unio coruscus var. frvanus SIMPSON, Syn., 1900, p. 714.
Var. diozensis S. H. Wright.

Shell subsolid, sometimes almost thin, narrowed at the an-
terior end and rather high on the dorsal margin at the poste-

UNIO 622

rior end of the laterals: epidermis dark, sometimes dull and
black.

Length 35, height 20, diam. 13.5 mi.

Length 57, height 28, diam. 20 mm.

Type locality, Lake Diaz, Volusia Co., Fla. Also Lake
Beresford; Lake Ashby, Florida.

Umo diazersis S. H. Wricut, Naut., XI, 1897, p. 5.
Unio coruscus var. fryanus (part), Stmeson, Syn., I1goo, p.

714.

This varies insensibly into var. fryanus and to the ordinary
manifestation, though some of the specimens are remarkably
different from typical coruscus.

UNIO TENUISCULUS Frierson.

“Shell transversely elliptical, rather solid, quite small, being
the smallest member of the great buckleyi group yet published ;
smooth, eradiate (except when quite young), brown-olive,
shining on the sides, the posterior area rough and dull; dorsal
and basal margins nearly parallel (the former a little arched
in some examples}. Posterior point low and widely biangu-
late; truncate in front. Nacre purple and salmon-colored.
Teeth double in left, single in right valve, quite stout.

Length 36.5, alt. 20, diam. 14.5 mm.” (Frierson).

Type locality, Reedy ake, Polk: Co., Fla.

Unio tenuisculus Frierson, Naut., XXV, IgII, p. 29, pl. 1,

figs. 4) 56.

“The shell is differentiated from U. coruscus by being small-
er; by its parallel outline; by its posterior point being lower
and biangulate. In proportion to size, it is heavier in texture,
and when perfect shells of both are compared, it is not so
shining as is coruscus. The squarely built anterior end is a
character common to a number of Florida Uniones.”

Unio Ferrissit Marsh.

Shell nearly elliptical, solid, convex, inequilateral; dorsal
and ventral lines rounded; anterior end subtruncated; dorsal
slope obliquely truncated, meeting the dorsal line at a low

634 UNIO

angle; beaks rather high, their sculpture not seen; posterior
ridge well developed, subangular, ending below the median
line in a point; surface nearly smooth; epidermis dark green
or blackish with capillary rays, shining; posterior slope some-
what wrinkled; pseudocardinals compressed, solid, single in
the right valve and double in the left; laterals short, slightly
curved; anterior muscle scars very deep; posterior scars well
marked; nacre pink, iridescent.

Length 57, height 30, diam. 22 mm.

Type locality, small creek near Palatka, Florida.

Umo ferrissi Marsyu, Naut., V. 1891, p. 30.—Simpson Pr.
U.S. Nat. Mus., XV, 1892, p. 423, pl. LxvI, figs. 1, 2;—Syn.,
IQOO, p. 719.

Allied to U. buckleyi and dorei, but I cannot unite it with
either. Unlike U. buckleyi it has the posterior ridge strong
and the dorsal slope wrinkled, and on the other hand it is
much less inflated than U. dorei and is differently colored. It
seems to be one of the nondescripts of the puzzling buckleyi
group, which can neither be properly separated from other
allied forms nor united with them.

Unto borer B. H. Wright.

Shell subrhomboid, the upper and lower outlines being some-
what rounded, solid, inflated, inequilateral; beaks full and
high, their sculpture not seen; posterior ridge high, angled
above, slightly double below, ending in a feeble, narrow bian-
gulation below the median line: dorsal slope obliquely trun-
cated, meeting the dorsal line at an angle; anterior end sub-
truncate, angled above: surface nearly smooth; epidermis red-
dish-brown, ravless, shining; left valve with two compressed
pseudocardinals and two curved laterals; right valve with two
pseudocardinals, the upper smaller, and one lateral; muscle
scars impressed, nacre brilliant salmon, iridescent behind.

Length 66, height 41, diam. 29 mm.

Type locality, Lake Monroe, Florida.

Unio dorei B. H. Wricut, Pr. Ac. N. Sci. Phila., 1888, p. 115,
Stmrsoan, Syn., 1900, p. 719.

ploauetioeen

UNIO 635

I have only seen the type of this. It is rather short, solid,
inflated, with a high, sharp posterior ridge. ‘The epidermis is
bright, rich brown, and on the posterior slope there are traces
of two faint radial ridges. The pseudocardinals are rather
compressed for so solid a shell; the nacre is very rich and
brilliant. In some respects it seems close to U. buckleyi, but
the high sharp posterior ridge and subrhomboid form ally it
to the crassidens group.

Unio CUNNINGHAMI B. H. Wright.

Shell usually subrhomboid, sometimes decidedly rhomboid,
solid, subinflated to inflated, inequilateral; beaks apparently
full and somewhat elevated, but too much eroded in all the
examples seen to show any characters; posterior ridge de-
cidedly developed, narrowly rounded, ending in a rather sharp
point at or near the base; ventral outline generally straight, oc-
casionally a little incurved; anterior end rounded or truncate,
usually angled above; dorsal slope obliquely truncated ; surface
with irregular growth lines; epidermis shining greenish-yel-
low, tawny, ashy-brown or brown, sometimes clouded or faint-
ly rayed with green; pseudocardinals compressed to solid, rag-
ged; laterals short and curved; muscle scars small and im-
pressed: nacre silvery, purplish, salmon or reddish, often
bright.

Length 52, height 39, diam. 23 mm.

Length 46, height 26, diam. 24 mm.

Florida.

Type locality, Lakes of Sumpter Co., Fla.

Unio cunningham: B. H. Wricut, Pr. Ac. N. Sci. Phila., XIII,
1883, p. 58. pl. 1, figs. I-4——Sr1mpson, Pr. U. S. Nat. Mus.,
XV, 1892, p. 422, pl. Lxv, fig. 6;—Syn., 1900, p. 714. -
Closely related to U. micans and U. coruscus. It is solider

and more inflated than the former, is generally lighter colored

than the latter, and is more decidedly rhomboid and has a

higher posterior ridge than either.

636 UNIO

xu

Unio MICANS Lea.

Shell subelliptical or subrhomboid, “convex, inequilateral,
rather thin to subsolid; beak only moderately raised and full,
their sculpture a few strong, subconcentric ridges, which are
strongest where they cross the posterior ridge; posterior ridge
full, narrowly rounded, ending behind in a blunt point below
the median line; surface generally smooth; epidermis ashy-
green or yellow-green, faintly rayed or rayless; left valve
with two small, subcompressed pseudocardinals and two deli-
cate laterals; right valve with one pseudocardinal and one
lateral; baek cavities shallow; muscle scars not impressed;
nacre bluish-white, rather dull.

Length 50, height 26, diam. 17 mm.

North Carolina to South Georgia and Florida.

Type locality, Catawba River, Gaston Co., and Deep River,
Gilt INC:

Unio micans Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 85; Jl. Ac.
N. Sci) Phila; V; 1862;. p50, pl-1m, fie. 2075;-Obs.. Vine
1862, p. 63, pl. m1, fig. 207—Sowrrpy, Conch. Icon., XVI,
1866, pl. xxxv, fig. 182-——Srmpson, Pr. U. S. Nat. Mus.,
XV, 1892, Dp. 423, pl. Lxv, fig. 3;—-Syn., 1900, p. 714.

Margaron (Unio) micans Lea, Syn., 1870, p. 45.

Unio perlucens Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 193;
jlo Ae. No Sei: Phila, VE 11866; pa 18, plies tie 210. Obs
Xe, 1867,p. 220 pl. vse: 16:

Margaron (Unio) perlucens Lea, Syn., 1870, p. 45.

Close to cumninghanu but thinner, less rhomboid, and with

a lower posterior ridge.

Unio LEHMAN S$. H. Wright.

Shell short elliptical, solid, convex, inequilateral ; beaks only
moderately full or high, their sculpture not seen; posterior
ridge full, faintly double, ending behind in rather narrow
biangulation just below the median line; surface nearly smooth,
yellowish-green to olive or brownish, faintly rayed, shining :
left valve with two heavy pseudocardinals and two laterals;

UNIO 637

right valve with one pseudocardinal, a vestigial one above it

and ene double lateral; beak cavities shallow; muscle scars

small, impressed; nacre dull purple.

ength 70, height 45, diam. 27 mm.

Type locality, St. Mary’s River, Florida.

Unio lehmanu S. H. Wricut, Naut., X, 1897, p. 138.—SriMp-
son, Pr. Ac. N. Sci. Phila., 1900, p. 8o, pl. Iv, fig. 9 ;—Syn.,
1900, p. 715. }

A short, nearly elliptical, solid, convex shell, with shining
epidermis and double laterals in the right valve. The nacre
is dull, but slightly iridescent behind.

UNIO RURTCHIANUS 9S. H. Wright.

Shell long elliptical, subcompressed or convex, solid, inequi-
lateral ; beaks apparently only moderately full or high; poster-
ior ridge well developed, somewhat double, ending in a nar-
row biangulation at or a little below the median line; surface
nearly smooth; epidermis tawny, more or less rayed with
green; in the type, a voung shell, the green color preponder-
ates; left valve with two rather small, ragged pseudocardinals
and two curved laterals; right valve with two pseudocardinals,
the upper small, and one lateral, which sometimes is partially
double; beak cavities shallow ; muscle scars small, impressed ;
nacre copper-colored, sometimes tinted salmon.

Length 53, height 20, diam. 16 mm.

Length 62, height 38, diam. 20 mm.

Type locality, St. Mary’s River, Florida.

Unio burtchianus S. H. Wricut, Naut., X, 1897, p. 137.—
Simpson, Pr. Ac. N. Sci. Phila., r900, p. 80, pl. iv, fig. 8 ;—
Syn., 1900, p. 715.

Too close to U. lehmanti. The only differences I can see are
that this species is a little lower in proportion and less inflated
than that species. The nacre of the three specimens | have
seen is a little warmer in tint, but this is a character of very
trifling value. The measurements first given are for the type,
a young shell which shows quite green from the large num-

638 UNIO

ber of faint, green rays that partly coalesce. The other incas-
urements are from a shell which approaches more nearly to
U. lehmanii.

UNIO CHIPOLAENSIS Walker.

“Shell ovate, not very thick, somewhat inflated in the um-
bonal region, evenly rounded before and biangulate behind
with a slight emargination just above the superior posterior
angle; dorsal margin decidedly curved; basal margin slightly
but regularly curved; epidermis smooth, chestnut-colored,
darkening to black on the umbones, with several darker lines
indicating arrested periods of growth. Umbonal slope well
rounded towards the beaks, but flattening out and becoming
slightly biangulate posteriorly. Beaks prominent, apparently
incurved when perfect. Cardinal teeth compressed, crenulate ;
those in the left valve are nearly in a straight line. Lateral
teeth rather long, slender and slightly curved. Cicatrices dis-
tinct. Cavity of the beaks large and rounded. Nacre salmon-
color, darker anteriorly.

Length 56.5, height 32, diam. 22 mm.” (Walker).

Type locality, Chipola River, Fla.

Unio chipolaensis WALKER, Naut., XVIII, 1905, p. 135, pl. 1x.

HES AOsK7.

“This species is a member of the group of U. buckleyi and
is distinguished by the smooth, chestnut epidermis, entirely
without rays, but ornamented with concentric dark bands
such as occur in Pleurobema chattanoogaensis, inflated um-
bonal slope and biangulated posterior extremity with a slight
emargination above. It is related to some forms of U. burtch-
ianus B. H. Wr., but differs in being less elongated and more
inflated with more prominent beaks. The color both of the
epidermis and nacre is also quite different.”

UNIO CONFERTUS Lea.

Shell usually more or less rhomboid, though sometimes
nearly elliptical or slightly obovate, subsolid to solid, subin-
flated to inflated, inequilateral; beaks moderately full and high,

UNIO 639

their sculpture consisting of numerous ridges that run nearly

parallel with the growth lines; posterior ridge full, rounded

above. inclined to be narrowly double below, ending behind
in a blunt point or faint biangulation below the median line;
surface with irregular growth lines, nearly smooth, tawny
and feebly rayed with green in young shells, reddish-brown
or black, often rough and dull-colored when adult; left valve
with two strong, ragged pseudocardinals and two curved lat-
erals; right valve with two pseudocardinals, the upper small,
and one lateral; anterior scars impressed; posterior scars
shallow ; nacre varying from dull pinkish-purple to bluish or
whitish.

Length 96, height 55, diam. 37 mm.

Length 68, height 39. diam. 30 mm.

North Carolina to Florida.

Type locality, Santee Canal, S. C.

Umio confertus Lea; Tr. Am. Phil. Soc., V, 1834, p. 103, pl.
xvi, fig. 47; Obs., I, p. 215, pl. xvi, fig. 47—HANLEvy, Biv.
Shells. 1843, p. 200, pl. xx, fig. 24.—Sowrrsy, Conch.
Icon., XVI, 1866, pl. xxxv, fig. 185—Simpson, Syn., 1900,

aise

Margarita (Unio) confertus Lea, Syn., 1836, p. i

Margaron (Unio) confertus L&A, Syn., 1852, p. 33; 1870, p. 53.

Unio lugubris Lea, Tr. Am. Phil. Soc., VI, 1838, p. 30, pl. 1x,
nee 25 Obs., [1 .1838, p30, pls1x, fie. phe poe Biv.
Shells, 1843, p. 206, pl. xx, fig. 9-—CHENUu, Bib. Conch.,
Tstsset. ll, 1645, p. Sappl. xv. fies. gia, 1 Conch... 1858,
pl. xx, figs. 3, 3¢, 3b.—Sowersy, Conch. Icon., XVI, 1868,
pl. LXxx, fig. 423-——Simrson, Pr. U. 8. Nat. Mus., XV,
§OO2).p). 434. pl, LXVI, fig. 4.51. xVvin, fi2., 1.

Margarita (Unio) lugubris Lea, Syn., 1836, p. 37; 1838, p. 24.

Marzaron (Unio) lugubris Lea, Syn., 1852, p. 38; 1870, p. 53.

Unio geddingsianus Lea, Pr. Am. Phil. Soc. I, 1840, p. 285;
VrsAm. Phil. Soc., Vill, 1842; p-2o2, pl. x1, fig: 155, Obs.
IIT, 1842, p. 4o, pl. x1, fig. 15. —-CHenu, II]. Conch., 1858,
pl. xxx1, figs. 3, 3a, 3b.

i)

640 UNIO

Margaron (Unio) geddingsianus Lea, Syu., 1852, p. 33; 1870,
P- 53-

Unio limatulus Conran, Pr. Ac. N. Sci. Phila., IV, 1849, p.
164; Jl. Ac. N. Seu Phila. tf 1850; p»276; pli xxv hee @)

Margaron (Unio) limatulus Lia, Syn., 1852, p. 32; 1870, p.
52)

Unio whiteianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 258 pl.
xiv, fig. 8.—Obs., V, 1852, p. 14, pl. xiv, fig. 8.

Margaron (Unio) whiteianus Lea, Syn., 1852, p. 33; 1870, p.
53:

Unio vibex Conran, Pr. Ac. Phila., VI, 1853, p. 260.

Unio similis Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 169; Jl.
Ac. N= Sci. Phila: lV, 1858,"-p0L pl sxpe fee 7ie Obs.
Vi, 1858sp. 01, plex the, ie

Margaron (Unio) similis Lea, Syn., 1852, p. 52; 1870, p. 53.

Unio protensus Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 88;
JL sAcON: Sei, Phila.y Vil 1866) pe-256, pl: sexx i tees
Obs., X11. 1860; p16) pl: xxxi, fie. 70

Margaron (Unio) protensus Lea, Syn., 1870, p. 60.

Unio radiolus Les,-Pr: Ac. Nese. Phila; 1621871, ps 1925 9k
Ac. N. Set. “Phila, VIL, 1874; p21, pls vi, fies 1820 bs.
XIII, 1874, p. 25, pl. vi, fig. 18.

Another very variable species, some specimens of which
show an affinity for the complanatus group. Generally the
shell is rather rhomboid, subinflated and solid. The epidermis
is darker and the surface is more concentrically sculptured
than in U. bucklevi.

Unio 1nsutsus Lea.

Shell rather small, rhomboid, subinflated to inflated, in-
equilateral, subsolid to solid; beaks full and elevated, their
sculpture not made out; posterior ridge well developed, single
or double, ending behind at the base of the shell in a blunt
point or biangulation; surface sometimes nearly smooth but
generally with rude growth lines; epidermis dull ashy-green
to brownish or blackish, occasionally very faintly rayed; left
valve with two small, subcompressed or stumpy, rough pseudo-

UNIO 641

cardinals and two curved laterals ; right valve with two pseudo-
cardinals, the upper small, and one lateral; beak cavities gen-
erally shallow ; nacre dirty bluish or purplish-white.
Length 60, height 34, diam. 22 mm.
Length 48, height 26, diam. 17 mm.
Length 43, height 26, diam. 18 mm.
North Carolina to Florida.
‘Type locality, Roanoke River, Weldon, N. C.

Unio msulsus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 86; Jl.
Ac seeock Pnitla, bX. 1862) p. 53, pl. 1, fig: 199; /Obs.,. VIII,
1862, p. 57, pl. L fig. 199.—Stmpson, Pr. U. S. Nat. Mus.,
mV, 1802; p- 422. pl rxv, fies. 1, 5< Syn., 1900; p. 716.

Margaron (Unio) insulsus Lea, Syn., 1870, p. 53.

Unio hicidus Lea. Pr Ac. N. Sci: Phila, VIL, 1863, p. 192;
joke. NO Se Phila. V1, 1866, pxo,-pl. 11, fig. 6; Obds., X61,
FO07, p:-13, pl. 11, fig. 6.

Margaron (Unio) lucidus Lea, Syn., 1870, p. 48.

Unio cistelliformis Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. |
[D2 fk Ac. SclLaPhilas NI, «1866, p: 10,, pl. vin fig. 375
Obs. Ki 1867, pi 23, pl. viy fis. 17:

Margaron (Unio) cistelliformis Lea, Syn., 1870, p. 52.
Smaller, more generally and decidedly rhomboid than its

near ally U. confertus. It is usually a rougher, dirtier, duller

colored shell than that of confertus.

UNIO OBNUBILUS Lea.

Shell subrhomboid, convex or subinflated, subsolid to solid,
inequilateral ; beaks not much elevated or inflated, their sculp-
ture not observed; posterior ridge well developed, double,
ending behind in a faint biangulation below the median line ;
surface with low, irregular growth lines, rather smooth, cov-
ered with a greenish-brown epidermis, which is rarely very
feebly raved, subshining; left valve with two stumpy, rough-
ened pseudocardinals and two curved laterals; right valve
with two pseudocardinals, the upper low and indistinct, with

642 UNIO

one lateral; beak cavities shallow; muscle scars impressed;

nacre purplish. salmon or fesh-color, generally bright.

Length 66, height 38, diam. 22 mm.

Length 67, height 40, diam. 24 mm.

South Carolina to Florida.

Type locality, Buckhead Creek, Burke Co., Ga.

Unio obnubtlus Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 169;
Jip AcuN- Say Phila:, 1V) 1858p. S4, pk xviny ie.64-*Obss
VI, 1858, p. 84, pk xvi, fig. 64.—Simpson, Pr. U: S. Nat.
Mus., XV, 1802; p.’ 424, pl. TxviG fies 35 Syl clOOo, pa 710:

Margaron (Unio) obnubilus La, Syn., 1870, p. 53.

Uimo opacus Lua, Pr. Ac. N. Sc. Phila, VX; 1857; p; 169; |i
ANe.N. Sci. Phila. IV, 1858, pa xvi ic.66; Obs, VWailerees:
p--86, pl xvii; he. 66.

Margaron (Unio) opacus Lea, Syn., 1870, p. 52.

Unio equatus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 170;
ji. Ac: N.-Seu Phila 1858, p: 80, pl* xix hie. Gos Obs: Va.
1858, p. 80, Pl-x1x, fies 60:

Margaron (Unio) equatus Les, Syn., 1870, p. 52.

Unto viridicatus Lea, Pr. Ac. N. Sci. Phila., 1X, 1857, p. 170;
JisAc. N.Set. Phila., TV, 1858, p: 87; pk xvi he: 67 Obs:
VI, 1858;'p187 pl xviig shes 67:

Margaron (Umo) viridicatus LEA, Syn., 1870, p. 52.

Unio hepaticus Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 154;
Jl AceN: Se. *Pinla.. TV 51860, pu-346e pl aLuin phoasie
Obes V Mik pe Bos pls Evite ae

Margaron (Unio) hepaticus Lea, Syn., 1870, p. 52.

Unio santeénsis LEA, Pr. Ac. N. Sci. Phila., I, 1871, p. 193.—J}.
Ac..N Sci >Phila,, Vill e1874)p) 20; pl vi, shige Ones
XIN, 1874, p:924. pl. vig tig. 17:

Unio nolan BeoHi> Wricht, Pr Ac. Ne Sem Bila. s16se.p
L103) pls nV, fig.

This is a sort of exaggerated U. occultus. It is generally
more rhomboid, larger and heavier than that species and has
a more northerly range. Occasional specimens are somewhat
produced in the post-basal region.

UNIO 643

Unio Fuscatus Lea.

Shell long elliptical or slightly obovate, compressed or sub-
compressed, rather thin; beaks low, somewhat compressed,
their sculpture consisting of subconcentric, subnodulous
ridges; posterior ridge !ow, usually more or less double, end-
ing behind at and below the median line in a feeble biangula-
tion; surface nearly smooth; epidermis pale reddish-brown or
ashy-brown, often feebly rayed with green, shining in the
young shells, showing lamellz in the later growth and often
covered behind with hair-like conferve; left valve with two
small, ragged pseudocardinals and two delicate, curved lat-
erals; right valve with two pseudocardinals, the upper small,
and one lateral; beak cavities shallow; muscle scars scarcely
impressed ; nacre coppery or purplish.

Length 67, height 36, diam. 18 mm.

I,ength of type, 44. height 22, diam. 12 mm.

Length 45, height 27, diam. 14 mm.

Florida.

Type locality, Black Creek, Fla.

Unio fuscatus Lea, Desc. 12 Uniones, 1843, (no pagination).
tei. mil SOC, 1X, Tots? p. 277, pl. xt, fie: 4; Obs:
IV, 1848, p. 35, pl. x1, fig. 4.-—Kuster, Conch. Cab. Unio,
1848, p. 203, pl. Lxvii, fig. 2—Rereve, Conch. Icon., XVI,
1865, pl. xx1, fig. 95.—Simpson, Pr. U. S. Nat. Mus:, XVI,
IeO2i ps 420; pls LX, fSS..2. 45" Syil., 1900, p..717:

Margaron (Unio) fuscatus LEA, Syn., 1852, p. 30; 1870, p. 48.
Young shells of this species are very close to U. occultus

and certain specimens of U. tortivuws, but are generally a little

more delicate than either. The older shells are thinner and have

a peculiar texture and a coppery tint not seen in either of the

above-mentioned forms. The old shells often become some-

what rhomboid, widening out at the posterior end, and the
epidermis is roughened on account of being pinched up into
delicate lamellz. Old shells often have a considerable growth
of hair-like conferve at the posterior end. I have a dwarf,
stunted form before me from Juniper Creek, Lake George,
Flerida, which is much narrowed in front.

644 UNIO

Unio occut'tus Lea.

Shell somewhat obovate or subrhomboid, a little narrowed
in front, inequilateral, subcompressed or convex; beaks only
moderately full or high, their sculpture consisting of nearly
longitudinal ridges; posterior ridges usually faintly double,
ending at and below the median line in a biangulation; post-
basal region generally a little produced ; surface nearly smooth,
tawny-brown, usually closely covered with faint green rays,
sometimes almost rayless and dark brown; left valve with two
subcompressed pseudocardinals and two curved laterals; right
valve with two pseudocardinals, the upper small and one lat-
eral; muscle scars slightly impressed; nacre purple, sometimes.
a little coppery-tinted.

Length 52, height 28, diam. 18 mm. (type).

Florida.

Type locality, Black Creek and Lake Monroe, Fla.

Unio occultus Lea, Desc. 12 Uniones, 1843 (no pagination ).—
Tr. Am. Phil.-Soc.; 1X>.1845°;,\p. 270. plexus ne 7 Ops,
IV, 1848, p. 37, pl. x11, fig. 7—Kustrer, Conch. Cab. Unio,
1861, p. 223, pl. LXxv, fig. 3—Simeson, Pr. U. S. Nat. Mus.,
XV, 1892, p. 420, pl. Lx, figs. 5, 6; Syn., 1900, p. 717.

Margaron (Unio) occultus Lima, Syn., 1852, p. 48; 1870, p. 48.
An exceedingly puzzling form, which varies toward fuscatus,

tortivus and even coruscus. It is generally a little solider,

darker and more inflated than fuscatus and has a little differ-
ent texture. It is not quite so rhomboid as most specimens of
tortivus nor is it arcuate; it is less solid and inflated than corus-
cus. But there seems to be a set of connecting links, which
more or less perfectly unite the above and several other so-
called species of this excessively variable and puzzling group.

Unio arctatus Conrad.

Shell elongated, compressed or subcompressed, usually ar-
cuate, inequilateral. subsolid; beak low, compressed, their
sculpture strong, corrugated ridges, which nearly follow the
growth lines: posterior ridge low, usually faintly double, end-

,

UNIO 645

ing behind below the median line in a somewhat rounded bian-

gulation; dorsal-slope obliquely truncated; basal line usually

incurved ; surface smoothish, or marked with irregular growth
lines: epidermis greenish-yellow to tawny-brown, red-brown
or black, feebly rayed, smooth and shining in young or finely
preserved adult specimens, rough and dark in old ones; left
valve with two low, small but stumpy, pseudocardinals and two
remote laterals; right valve with one pseudocardinal and one
lateral; beak cavities very shallow; muscle scars not deep;
nacre purple, rarely white, iridescent behind, usually dull in
front.

Length 63, height 29, diam, 14 mm.

Length 50, height 23, diam. 13 mm.

Florida; South Georgia; west to the Black Warrior River,

Alabama.

Type locality, Black Warrior and Alabama Rivers.

Unio arctatus Conrad, Am. Jl. Sci., XXV, 1834, p. 340, pl. 1,
fig. 9; New F. W. Shells, 1834, p. 36, pl. v, fig. 4—HANLEy,
Biv. Shells, 1843, p. 207, pl. xxi, fig. 47,—CHENU, Bib.
Conch., Ist ser., III, 1845, p. 19, pl. 111, fig. 10.—KuSTER,
Conch. Cab. Unio, 1861, p. 195, pl. Lx, fig. 3.—Srmpson,
Syn., 1900, p. 717.

Margarita (Umo) arctatus LEA, Syn., 1836, p. 38; 1838, p.

Margarita (Unio) arctatus Lia, Syn., 1836, p. 38; 1838, p.
This species has a very wide distribution and is exceeding

abundant. Conrad’s shell is higher behind than in front, is

compressed, black and quite elongated, as well as arcuate.

There is every possible variation to shorter, lighter colored,

more inflated forms, which are not at all arcuate. The species

seems close to U. lazarus and, if it did not insensibly run into
elliptical or obovate forms in Florida, I should place it in the
group of U. complanatus.

iS)

to

Sie
5.
ly

Var. tortivus Lea.

Under this name it may perhaps be well to place the ordi-
nary southern manifestation of this protean species, which
generally is not quite so elongated or arcuate as the type. In

646 UNIO

many cases shells that I refer to this form are irregularly el-

liptical or rhombic obovate. U. purpurellus seems to me to be

only a small, rather inflated form of tortivus.
Type locality, Chattahoochee River, Columbus, Ga.

Unio. tortivus Leas Pry Amr PhilvSocal11840..p. 2875
Am; Phil. Secs Villy r842apr2045-plasaiehicn1 7) @psss ile
1842, p. 42, pl. xu, fig. 17—CueENu, Ill: Conch., 1858, pl.
XXIX, figs. 6, 6a, 6b.—Sowerby, Conch. Icon., XVI, 1866,
pl. xxxvi, fig. 193.—Simpson, Pr. U. S. Nat. Mus., XV,
1892,-p422, pl. LAM, fige8; LX1V, hes. Ty 3304:

Margaron (Umio) tortivus Lea, Syn., 1852, p. 33; 1870, p: 53-

Unio arctatus var. tortivus SIMPSON, Syn., 1900, p. 718.

Omo.tetncus Lea, Pr. Aco NE Sc Pina oe 1857. pate;
jl Acs Ns Sci“ Phila, IVG1850;) po 1G5.ipl sem dies 7 Oerebse:
VI. 1850,..p. 13,° pl. xxi, fig. 78. Kuster: 1Conche abt
Unio, 18624 p:)276.pl? xer, ties 7.2 KCiliy ne

Margaron (Unio) tetricus LEA, Syn., 1870, p. 53.

Unio purpurellus Lea, Pr..Ac. N. Sci. Phila., 1X, 1857, .p. 171;
Ji. Ac. N. Sei. Phila., TV, 1859, p. 19, pl. xx1n, fig: 81; Obs., .
VIL) 18503, px 16, pla xxi, eS:

Margaron (Unio) purpurellus Lea, Syn., 1870, p. 53.

Unio merceri lasa, Pr. Ac. N. Sci. Phila., VI, 1862, p. 169; Jl.
Ac: Ni: Ser. Pinlas VV, 1862,"p 200. pl. xxx, fre 275 Obs.
DXE* 7863 pi3 tcp kx, hee e7G:

Margaron (Unio) mercerit Lea, Syn., 1870, p. 61.

UNIO NIGELLUS Lea.

Shell subrhomboid, narrowed in front, subinflated, inequi-
lateral ; beaks slightly elevated and inflated, their sculpture con-
sisting of numerous corrugated, somewhat doubly-looped
ridges ; posterior ridge full, double, ending behind in a feeble
biangulation at or near the base of the shell. The shell is most
strongly inflated along the posterior ridge, in front of which
it is somewhat wedge-shaped; posterior slope obliquely trun-
cate; base line nearly straight, sometimes a little full behind
the middle; anterior end rounded and narrow; surface with
irregular growth lines, dirty greenish and rayed in the young

UNIO 647

state, dark brown or black when old, subshining ; pseudocar-

dinals small, rough, stumpy; laterals short, remote; muscle

scars small, well marked ; nacre silvery, white, salmon, copper-
color or purplish, iridescent behind.

Length 56, height 30, diam. 18 mm.

Length 43, height 24, diam. 14 mm.

length 39, height 21, diam. 12 mm.

Chattahoochee Kiver system; south into Florida.

Type locality, Chattahoochee River, Columbus, Ga.

Unio nigellus Lea, Pr. Am. Phil. Soc., V, 1852, p. 251; Tr.
Am Phil Soc: Xs 1852; .p4 263) plo xxiv, fig. 42> Obs. V,
1852, p. 39, pl. xxiv, fig. 42—SIMPSON, Syn., 1900, p. 718.

Margaron (Unio) mgellus LEA, Syn., 1852, p. 30; 1870, p. 53.

Unio demgratus Lea, Pr. Ac. N. Sci..Phila., 1X, 1857, p. 171;
Jl. Ac. N. Sci. Phila., IV, 1859, p. 200, pl. xx111, fig. 83 ; Obs.,
VII, 1859, p. 18, pl. xx, fig. 83.—Simpson, Pr. U. 8. Nat.
Mus., XV, 1892, p.\422, pl. Lxv, figs1.

Margaren (Unio) denigratus LEA, Syn., 1870, p. 52.
Distinguished from related species by being considerably

higher behind than in front, by having the greatest diameter

at the posterior ridge and by its soft, rich nacre.

Unio pPiner B. H. Wright.

Shell long rhomboid, subinflated, subsolid, inequilateral ;
beaks apparently not very high or full, their sculpture not
seen; posterior ridge full, angled, narrowly double, ending be-
hind in a feeble biangulation at or near the base of the shell ;
dorsal and ventral lines nearly straight and parallel; dorsal
slope obliquely truncated above; anterior end rounded and
slightly angled above; surface nearly smooth; epidermis with
delicate lamella, but shining, reddish-brown, tawny and green,
faintly rayed in fine specimens; pseudocardinals subcom-
pressed, ragged; laterals nearly straight; muscle scars shal-
low ; nacre white, purple, brown or copper-colored, rather rich
and bright: iridescent behind.

Length 66, height 31. diam. 20 mm.

North Florida.

Type locality, Lake, Hernando Co., Fla.

648 UNIO

Unio pine: B. H. Wricut, Naut., XI, 1897, p. 40.—Simpson,
Pr. Ac; N.Set., Phila, 1900; prso, pip, fis? PSyn. 1900;
pazvic: ;

Unio suttoni B. H. Wricut, Naut. XI, 1897, p. 56.

Possibly a decidedly rhomboid form of U. buckleyi. Two
shells before me from Saratoga, Florida, agree very well with
this, but are darker and practically rayless. U. suttoni does
not seem to me to be specifically or even varietally different.

Unio oscar B. H. Wright.

Shell elongated, subsolid, inflated, irregularly elliptical or
suhrhomboid, inequilateral; beaks apparently full and high,
their sculpture not seen; posterior ridge high, angled and sin-
gle above, narrowly and faintly double below, ending in a
biangulation at or below the median line; dorsal and ventral
lines slightly rounded; dorsal slope subtruncated, anterior end
usually a little narrowed, rounded; surface with low, uneven,
concentric sculpture; epidermis tawny-brown, shining, rayed
in young shells; pseudocardinals low, subcompressed, often
partially obliterated; laterals remote, rather feeble; all the
teeth granular or somewhat vertically striate; muscle scars
.well impressed, large; nacre purple, coppery or bronzy.

Length 61, height 28, diam. 24 mm.

Florida.

Type locality, Creek from Lake Osceola, Winter Park, Fla.
Unio oscari B. H. Wricut, Naut., V, 1892, p. 124; IX, 1896,

p. 122, pl. 1, figs. 1-3.—StMPsON, Syn., 1900, p. 719.

Close to U. hazelhurstianus but more inflated, apparently
smaller, with brighter brown epidermis and less perfect teeth.

UNIO HAZELHURSTIANUS Lea.

Shell elongated, irregularly elliptical, inequilateral, convex
to subinflated, subsolid; beaks apparently not full or high; pos-
terior ridge double, ending in a biangulation at or below the
median line; dorsal and basal lines usually a little rounded ;
anterior end subtruncate, sometimes cut away slightly below
and angled above; epidermis black ; left valve with two stumpy

UNIO 649

pseudocardinals and two laterals, the upper smaller ; right valve

with one pseudocardinal and one lateral; muscle scars well

marked ; nacre pale brownish-purple, rather dull.

Length 77, height 32, diam. 21 mm.

Southern Georgia.

Type locality, Satilla River, Camden Co., Ga.

Unio hazelhurstianus Vea, Pr. Ac. N. Sci. Phila., II, 1858, p.
roost. Ac Ne Sei. Piila.,1V, 1850,/p: 201, pl. x xvi, fig. 92;
Obs.,. VII, 1859, p. 29, pl. xxvt, fig. 92,—Sowerby, Conch.
Icon., XVI, 1866, pl. xxxv, fig. 188-—Simpson, Syn., 1900,
Pp. 719.

Margaron (Unio) hazelhurstianus Lea, Syn., 1870, p. 60.

The surface is sculptured with rather fine, concentric ridges,
the epidermis is black and thick and unless rubbed is dull. Dr.
Lea has placed with his hazelhurstianus two shells, which |
am sure are naviculoides, that being a thinner, more rhomboid
form with smoother, lighter colored epidermis.

Unio PyGAMA&uS Lea.

“Shell smooth, elliptical, rather compressed, striate, rounded
before and angular behind: substance of the shell rather thin,
thicker before ; beaks somewhat prominent ; ligament short and
thin; epidermis dark brown, striate, with obscure rays, and
slightly polished ; umbonal slope angular; marks of growth in-
distinct ; cardinal teeth small, compressed; lateral teeth rather
long, linear, slightly curved and thickened at the posterior end ;
anterior cicatrices distinct ; posterior cicatrices confluent: dor-
sal cicatrices in the centre of the cavity of the beaks; cavity
of the shell shallow; cavity of the beaks small and angular ;
nacre blue and very iridescent behind.

Mength r2cheicht..7, diam. 4 inches?’ (Lea:)

Type locality, Abbeville District, S. C.

Unio pvemeus Les, Pr. Am. Phil Soc., V, 1852, p. 2: ;
Am. Phil. Soc., X, 1852, p. 262, pl. xv, fig. 14; Obs., V, 1852,
pl. 18, pl. xv, fig. 14——Stmpson, Syn., 1900, p. 715.

Margaron (Unio) pygmeus Lea, Syn., 1870, p. 48.

650 UNIO

“This is a very small species and a single valve only, (the
right), has been received by me. I do not think this is quite
adult. The beak is not sufficiently perfect to observe any un-
dulations. This shell is about the size of U. fabalis (nobis),
and parzvus Barnes, but cannot be confounded with either of
them. !t is a thinner shell than the former and less inflated
than: the lattem: at(Lean.

Only a single, broken valve, the right, is known. Lea de-
scribes and figures it, but it is evidently a very young shell,
too young to furnish reliable characters for identification. It
may belong in the buck/eyi group, but of that I cannot be cer-
tain.

Unio BuxTontI B. H. Wright. °
Shell much elongated, decidedly rhomboid, inequilateral,

convex; beaks low, scarcely inflated, their sculpture a few
longitudinal corrugations; posterior ridge high, angled, lead-
ing down to a point at the base of the shell; dorsal and basal
lines parallel; dorsal slope obliquely truncated, the truncation
meeting the dorsal line at an angle; anterior end cut away
below, rounded, subangulate above; surface with delicate
growth lines; epidermis tawny, covered with faint green rays,
shining ; pseudocardinals compressed, two in each valve, the
upper one of the right valve small; two straight laterals in the
left valve and one in the right ; muscle scars well marked ; nacre
rich copper-color, very bright.

Length 50, height 19, diam. 11 mm.

Type locality, Lakelets of Marion County, Florida.

Unio buxtoni B. H. Wricnut, Naut., XI, 1897, p. 55.—S1mMp-
son, Pr. Ac N. ‘Sci. Phila; 1900;-p.. 80, plh1, fe .65 Syl,
TOO, p. 710.

A rather remarkable form, the shell being much elongated
and decidedly rhomboid. It is probably nearest to U. pinei,
but is less inflated, more elongated in proportion and more
decidedly rhomboid. It is probable that the specimen before
me, whose measurements I have given, is young.

‘

UNIO 651

Group of Unio complanatus.

Shell elongate trapezoidal, moderately solid, but little inflat-
ed, nearly straight below; with a posterior ridge, and usually
biangulate behind; beaks not prominent, sculptured with sev-
eral coarse, parallel ridges, which follow the growth lines or
are nearly straight. Epidermis sometimes shining and feebly
rayed, becoming rough and rayless with age; laterals straight
or slightly curved; beak cavities shallow.

Animal with the marsupium occupying all or nearly all of
the outer branchiz; gills long, rounded below, inner much the
larger, free nearly or quite their whole length from the ab-
dominal sac.

Unio COMPLANATUS “Solander” (Dillwyn).

Shell generally rhomboid, inequilateral, subsolid to solid,
convex; anterior end rounded; dorsal and basal lines nearly
or quite parallel; dorsal slope obliquely truncated; posterior
ridge well developed, single or double, ending behind at or
near the base in a point or biangulation ; beaks not much raised
nor inflated, their sculpture consisting of strong ridges, which
run nearly parallel with the growth lines and are carried back
to the nucleus behind as delicate, radial lire; surface with ir-.
regular growth lines, often nearly smooth in young or well
developed shells, rough in old ones; epidermis tawny-green to
greenish-brown, often rayed and rather smooth in young shells,
becoming rough and dark in old ones; left valve with two
ragged pseudocardinals and two nearly straight laterals; right
valve with one pseudocardina!l and often a small one above it
with one lateral; beak cavities shallow ; muscle scars large, im-
pressed: nacre white, straw-color. salmon or various shades of
purple.

Length 105, height 55, diam. 33 mm.

Length 9o, height 55, diam. 30 mm.

Length 60, height 38, diam. 21 mm.

Length 62, height 40, diam. 25 mm.

652 UNIO

Atlantic drainage from the St. Lawrence to Georgia; west
in the British possessions to Manitoba?
Type locality, Maryland and New Jersey.

Mya complanata SOLANDER, manuscript (no date).—DILLwyn,
Cat.) re rgepe Sil

Unio complanata Dresuayes, An. sans Vert., 2d ed., VI, 1835,
P. 559.

Unio complanatus Gouup, Inv. of Mass., 1841, p. 107, figs. 68-
70.—BInnNkEY, 2d ed., Inv. of Mass., 1870, p. 167, fig. 472.—
Hantey, Biv. Shells, 1843, p. 199, pl. xx1, fig. 20.—DeE Kay,
Zool. of N. Y., Pt. 5, 1843, p. 188, pl. xx, fig. 246.—Kus-
TER, Conch. Cab. Unio, 1856, p. 137, pl. x11, fig. 2—Hart-
MAN and MicHENeErR, Conch. Cest., 1874, p. 86, fig. 187.—
SIMPSON, Syn., 1900, p. 720.

Margarita (Unio) complanatus laa, Syn., 1836, p. 30; 1838,
p: 22.

Margaron (Unio) complanatus Lea, Syn., 1852, p. 32; 1870,
Dp. sik

Elliptio complanatus OR?MANN, Ann. Car. Mus., VIII, 1912, p.
260.

? Unio violaceus SPENGLER, Skriv. Nat. Selsk. III, 1793, p. 55.

Unio purpureus Say, Nich. Enc., IH, 1817, pl. 1, fig. 1—Sow-
mRBY, Conch. Icon, XIV, 1868, pl. Lxvitt, fig. 346.

Mya purpurea Eaton, Zool. Text-Book, 1826, p. 2.

? Unio purpurea Desuayers, Encyc. Meth. II, 1827, p. 151, pl.
249, fig. 5.

Unio rarisulcata LAMARCK, An. sans Vert., VI, 1810, p. 72.
Unio coarctata LAMARCK, An. sans Vert., VI, 1819, p. 73-—
? Sowersy, Conch. Icon., XVI, 1866, pl. xxxiv, fig. 178.
Unio purpurascens I,AMARCK, An. sans Vert., VI, 1819, p. 73.

Unio georgina I,AMaRcK, An. sans Vert., VI, 1819, p. 74.

Unio rhombula L.aMarcx, An. sans Vert., VI, 1819, p.-74.—
? DELESSERT, Rec. Cog. Lam., 1841, pl. xu, fig. 8.

Unio carinifera LAmMarcK, An. sans Vert., VI, 1819, p. 74.—
Kuster; Conch: (Cab.. Unio; 1861, p.i76.4p bavi. tien.

Unio glabrata LAMARCK, An. sans Vert., VI, 1819, p. 75.

UNIO 653

Unio sulcidens LAMARCK, An. sans Vert., VI, 1819, p. 77.—
? DELESSERT, Rec. Coq. Lam., 1841, pl. x11, fig. 3.—CHENU,
Ili. Conch., 1858, pl. x11, figs. 5, 5a.

Unio virgimiana LAMARCK, An. sans Vert., VI, 1819, p. 79.

Unio fluviatilis GREEN, Jl. Mac. Lyceum, 1827, p. 41.

? Unio raveneli Conrad, New F. W. Shells, 1834, p. 39, pl. v1,
fig. 4.—CuHENu, Bib. Conch., 1st ser., III, 1845, p. 9, pl. 111,
fig. 8.

Margarita (Unio) watereensis Lea, Syn., 1836, p. 31; 1838,
p22.

Macbiroe (Unio) watereensis Lea, Syn., 1852, p. 33; 1870,

eee icone. H. and A. Apams, Gen. Rec. Moll., II, 1857,
Pp. 493-

Unio griffithianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 103,
pl. xv, fig. 46; Obs., I, 1834, p. 215, pl. xv, fig. 46—HANLeEy,
31v. Shells, 1843, p. 199, pl. xx1u, fig. 28.—KustER, Conch.
Cab. Unio, 1861, p. 208, pl. Lx1x, fig. 2—Sowerrsy, Conch.
Icon., XVI, 1868, pl. U.XxxIx, fig. 449.

Margarita (Unio) grifithianus Lea, Syn., 1836, p. 31; 1838,
pe 22:

Margaron (Unio) grifithianus Lea, Syn., 1852, p. 33; 1870,
p52:

Unio planilaterus CONRAD, Monog., XII (no date after 1838),
p. 103, pl. Lv, fig. 1.

Margaron (Unio) planilaterus Lea, Syn., 1870, p. 51.

Umio rufusculus Les, Pt. Am. Phil. Soc., V, 1852, p. 252; Tr.
Ag Phil Soc) XX, 1652hp. 250: pl. xav, fig. 7; Obs., V; 1852,
p. 14, pl. xtv, fig. 7—Sowerpy, Conch. Icon., XVI, 1868, pl.
Eerie hes 2377:

Margaren (Unio) rufusculus LEA, Syn., 1852, p. 33; 1870, p.
54-

Mya rigida Woop, Ind. Test. Rev., 1856, p. 200, pl. 1, supp.
Tee TO:

Umo abbevillensis Ura, Pr. Ac. N. Sci. Phila., I, 1857, p. 84;
jienc, IN SecePhila kV ,. aS5eaips ot, pi. V1, fig..34; :Obs.,
VI, 1858, p. 51, pl. vi, fig. 34.

Margaron (Unio) abbevillensis Lea, Syn., 1870, p. 52.

654 UNIO

Unio contractus Lea, Pr. Ac. N. Sci. Phila.; I, 1857, p. 86; JI.
Ace NSeicPhila:, V5 1802, .py203 ply xxix hee 27 27. Oss
TX) p25. pl., Sik owes

Margaron (Umo) contractus Lea, Syn., 1870, p. 61.

Umio virens LEA, Pr. Ac.'N. Sei) Phila.; 1X, 1857, p-169;"Jl:
Ae. WN... Sci. Phila., IV, 1858) paso, plaxvis fanGotObs- ir
1858, p. 80, pl. xv1, fig. 60.

Margaron (Unio) virens Lea, Syn., 1870, p. 52.

Umo savannahensis lea, Pr. Ac. N. Sci. Phila., [X, 1857, p-
1694/1. Ac-cN: Sci. Phila; IV3 1858.) p. St, pl, xis ee oi
Obs VilarScs; pSiapl. <vi, es One

Margaron (Unie) savannahensis LEA, Syn., 1870, p. 51.

Unio. subfiavus Lea, Pr. Ac. N: Sei. Phila., [X, 185759p5 170;
ji. Ac. .N: Sei. Phila, TV; 1858, p90, pl xmeies yo Ons.
VI. -858,"p.-00 pl: sax he. 7.0!

Margaron (Unio) subflavus Lea, Syn., 1870, p. 52.

Unio neusensis Lea, Pr. Ac. N. Sci. Phila., I, 1858, p. 41; Jl-
Ac. N. Sci. Phila., V, 1859, p. 60, pl. 1v, fig. 208; Obs., VIII,
1860, p. 64, pl. Iv, fig. 208.

Margaron (Unio) neusensis LEA, Syn., 1870, p. 51.

Unio exactus Lea, Pr. Ac. N. Sci. Phila., Il, 1858, p. 41; JL.
Ac. N. Sct, Phila; V;1862;p: 62, pl 1v, ‘ie 210; Obs eViae
1860, p. 66, pl. Iv, fig. 210.

Margaron (Unio) exactus Lms, Syn., 1870, p. 43.

Unio roswellensis Lea, Pr. Ac. N. Sci. Phila., I, 1858, p. 165;
WL AcaNoSc’ Philay DV6 1856, p 205, iplr xeaivs tong 7
@Obsiy Vil; 1850; p: 235 ply xx, nee.

Margaron (Unio) roswellensis Las, Syn., 1870, p. 51.

Unio postellii Lea, Pr. Ac. N. Sci. Phila., I, 1858, p. 165; Jl.
Ac. N: Sci. Phila., 1V- 1850, pa2i4 pl scxve fie nese Obs:
VII. 1850, p. 32, pl. Xxvt, fig. 94.—Sowersy, Conch. Icon...
XVI) 1866, pl. XIV, py 25s:

Margaron (Unio) postellii Lea, Syn., 1870, p. 51.

Unio baldwinensis Lea, Pr. Ac. N. Sci. Phila., IIJ, 1859, p-
1703: Jl. Ac, N. Sci. Phila? AW, 1860,.ps'330pl annie. 655).
Ohs.,, V IL, 1860, p: 12, pl. un) fies:

Margaron (Unio) baldwinensis Lea, Syn., 1870, p. 51.

UNIO 655

Umo raeensts Lea, Pr. Ac. N. Sci. Phila., IIT, 1859, p. 171; Jl.
ee OCe nila lV) (SOO, p., 330. pl. tit, fiss 156; Obs.,
NOUN S1S60, op: 1s ips Lin dies 156.

Margaron (Umo) racensis Lea, Syn., 1870, p. 52.

Umio quadratus Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 172;
JAC EN Sci, Phila, 1V, 1860,.p2 338: pl: Liv, fic. 163; Obs:,
Wi S00; px 20; pl. Liv; Tis. 163:

Margaron (Um) quadratus LEA, Syn., 1870, p. 4.

Unio squameus Wea, Pr. Ac. IN. Sci. Phila, V, 1861, p. 301;
itNca Ne sct “PhilaoV. 1862, p. 200, pli. xxvii, fig, 260;
Obs Xs 1803, ps 22, pl. xevint, fig) 260.

Margaron (Unio) squameus Lea, Syn., 1870, p. 51.

Unio lugubris Kuster, Conch. Cab. Unio, 1861, p. 234, pl.
BEX Tee Oan E.

Umo weldonensts Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p.
igi vme, Ni Sct Phila: Vi 1866. p. ti, ply a1. fie.

"Ops. dul, 1867, p.. 15, pl. mi, he. 8,

Margaron (Unio) weidonensis Lea, Syn., 1870, p. 51.

Unio gastonensis LEA, Pr., Ac. N. Sci. Phila., VII, 1863, p.
igus jl, Aer Nise) Phila; V1; 1866; p. 20, pl. vi, fig. 18;
Obs= XI 1867, ip. 24, pl. vi, fie 18:

Margaron (Unio) gastonensis Lea, Syn., 1870, p. 51.

Umio aberrans Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 191;
Acne toc, vei, Wil 1866, p. 7, pl. 1, fig. .3,-Obs., XI,
LSO75ps U1 « Pl Ii, figs 3.

Margaron (Unio) aberrans Lea, Syn., 1870, p. 52.

Unio mecklenbergensis Lea, Pr. Ac. N. Sci. Phila., VII, 1863,
De igi: ac. Ne Sci, Pinla. VI 18660) -p. 17, pl: v,. fig. 155
Olis. X11867, o. 21, pl. -v,, fig: 5:

Margaron (Unio) mecklenbergensis Lea, Syn., 1870, p. 5I.

Unio raleighensis Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p.
fon gh wee Ne Sci. enila Wil), 1866, pe. G6, pl: 1. fie. 2; Obs.,
Role ITSO 74. PALO, Pike tes. (2:

Marearon (Unio) raleighensis La&a, Syn., 1870, p. 52.

Unio mediocris Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 192;
Toe IN Sei, Phila.) Vij 1S66,.p. 245, pl: vis, fig. 22; Obs.
XI, 1867, p. 28, pl. vit, fig. 22.

Margaron (Unio) mediocris LEA, Syn., 1870, p. 52.

>

656 UNIO

Unio indefinilus Lea, Pr. Ac. N. Sct. Phila. Vil) 1862) p: G2:

Unio indefiutus Lea, Jl. Ac. N. Sci. Phila., VI, 1866,p. 15, pl.
Iv; figs. 125 Obs. 38 1867.70.12. plume tee ale.

Margaren (Unio) indefinitus Lea, Syn., 1870, p. 51.

Unio humerosus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 161 ;
fle Ac: ON. Sei, Phila: Vil, 1868," p3300, plexi, siosesienen:
Obs.,;, X11 1860; p61) pl XY, ie ons:

Margaron (Unio) humérosus LEa, Syn., 1870, p. 51.

Unio beaverensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 161;
Ji Ac. “N. Sci: Phila, Vip 1868.9. 207.0 pen ee Oe
Obs. SL 1860, p-557> pla saline Wen coo:

Margaron (Unio) beaverensis Lea, Syn., 1870, p. 52.

Unio blauverensis PTtEL, Conch. Sam., LI, 1890, p. 146.

? Umo neglectus SowERBy, Conch. Icon., XVI, 1868, pl. Lxv,
i122 320,

Unio tortuosus SOWERBY, Conch. Icon., XVI, 1868, pl. Lxv, fig.
330:

Unio uhareensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145;
jl. Ace ON. Set, Phila. VL 1868,. p; 304, plo <pva nes aoe.
Obs., XII, 1860, p. 63, pl. xLvi, fig. 116.

Margaron (Unio) uhareensis Lea, Syn., 1870, p. 52.

Unio nubilus Lea, Pr. Ac. N. Sei. Phila.) XII, 1868, p: 168;
jl, Ac: N, Sei Philax, V by S68; p= 208s pl cia neato
Obs:, X11 p. 58; pl ivy ne iro:

Margaron (Umno) nubilus Lima, Syn., 1870, p. 51.

Unio yadkinensis Lea, Pr. Ac. N. Sci. Phila., I, 1872, p. 156;
fl. Ac.wN.-Sei. Philay VI, 1874, p32, pl. Se ts 205 Oss
XIII, 1874, p. 36, pl. x, fig. 29.

Unio amplus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 157; Jl.
Aco N. Sci. Philas VII 1874, p30, ple xi. ie, 520-7 Ops.
AAT 18742 ps243>" pl. scum fies, 30

Unio ligatus ra, Pr. Ac. N. Sci. Phila, 11872 4p.157, 0
Ac: Ni Set) Phila., VIEL! 1874; p240, plitxvin, fey Obs.
XI, “1874, p: 53, pl. xvi tie: 47.

Unio subparallelus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 158;
Jl. Ac. N. Sci. Phila., VIII, 1874, p. 46, pl. xvr, fig. 44; Obs.,
XIII, 1874, p. 50, pl. xvi, fig. 44.

UNIO 657

Unio wrwinensis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 159;
Jl. Ac. N. Sci. Phila., VITI, 1874, p. 44, pl. xv, fig. 42; Obs.
XIII, 1874, p. 48, pl. xv, fig. 42.

Unio infuscus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 160;
Pisce N. oc, Phila, Vill, 1874, p. 51, pl. xvi, fig. 40:
Obs., XIII, 1874, p. 55, pl. xvn, fig. 49.

Umiorroims Tra, Pr. “ic. N. Sci. Phila., Il, 1872, p. 160; Jl.
Ac. N. Sci. Phila., VII, 1874, p. 52, pl. xvi, fig. 51; Obs.,
XIII, 1874, p. 56, pl. xvmt, fig. 51. .

Umo basalis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 161; Jl.
Ac. N. Sci. Phila., VIII, 1874, p. 48, pl. xvi, fig. 46; Obs.,
DOME TS 74." p. 52,‘ ply xvi, fie. 46.

Unio subolivaceus Lea, Pr. Ac. N: Sci. Phila., IIT, 1973), p:
A22 i Ac ON Sa. Phila; VIL 1874, "p. 57; pl. xx, fig. 56;
Ons 1874) p61, ple xx fies'56:

Unio infulgens LEA, Pr. Ac. N. Sciv Phila., III, 1873, p. 422;
ieAcwne sen Bhilai; WIT 1874, >p- 60; plo xx fig. 59; Obs.,
Xi 1874; ps 64, spl xt, fig-50.

Cmaarerratus aaa, (Pr Ac. N. Sei: “Phila. LI, 1873,;p: 422%
Pi SNcrNe oeioiila Wi 18745. p. 55; pl. xix, fies-533
Obs. 2c 1874. ps0, pl. xx, fig. 53.

Umo corneus LEA, Pr. Ac. N. Sci. Phila., II, 1873, p. 423; Jl.
On hes Sch eiid.. Ville 1674, 0p; 50; pl. xx), fic...58.5:Obs.,
Pane Tes Acc pod pl Sex, fig <5 8:

Arconaia provancheriana Piispry, Nat. Canadienne, XX, 1890,
fest teoin, Ae. Neila. LoQ24p. 132, pl.cwit, fiss.:4-6.

This species was described by Solander in Latin, but the
manuscript was never published and is now in the British Mu-
seum. Mr. Edgar A. Smith kindly examined it for me and
informed me that Dillwyn’s description in the catalogue is a
translation from Solander. The name Mya complanata was
used by Lister in Hist. Sive. Conch. (1770, p. 150), but Lister
was not a binomial author. The Portland Catalogue is anony-
mous and a mere sale list.

Complanatus Dillwyn and purpureus Say both date from
1817, and it is now impossible to determine which name had
actual priority. But in view of the fact that the name com-

658 UNIO

planatus had been used for this species by Lister and Solander
long before Say’s name was applied I think that the preference
should be given to the well-known name of Solander.

The above description is intended merely to cover the more
typical manifestations of this abundant and protean form. The
shells are often larger than the largest dimensions given, they
are sometimes smaller than the smallest measurement, they
may be more compressed or inflated in proportion to the length,
they may vary in form so that occasional specimens are al-
most evenly elliptical. In many cases the greatest diameter of
the shell is at the posterior ridge and it is wedge-shaped in
front of this; other specimens are regularly lenticular when
viewed from above. Dr. Lea and a number of other American
conchologists agreed on uniting under the name of Unio com-
planatus nearly all the forms of this group found north of
about the latitude of Washington. South of that they began
to apply specific names to the different variations, most of
which were no more divergent than the northern mutations.
When this was once begun there seemed to be no place to stop
for no two lots of shells of this exceedingly puzzling group
just agreed. ‘The result was a great multiplication of names
and almost endless confusion. I believe that the group of
which Unio complanatus may be taken as the type is one of
the most difficult to satisfactorily arrange of any of the
Naiades. I have gone over a large proportion of the types
and great quantities of material again and again in the en-
deavor, not to name up all the specimens before me, for that
would be impossible, but to draw some kind of specific lines
by which a majority of the material might be named and I have
found it well nigh a hopeless task. I have given varietal rank
to a few of the forms, which have somewhat marked and con-
stant characters.

Var. jejunus Lea.

Shell much compressed; posterior ridge widely doubie, end-
ing behind near the base in a wide biangulation; epidermis

UNIO 659

cloth-like. Sometimes slightly produced behind the center of
the base.

Length 98, height 50, diam. 21 mm.

Length 95, height 45, diam. 20 mm.

North Carolina and northward.

Type locality, Roanoke River, between Winton and Tarboro,

Ne C22 Camden? 1S. C.

Unio jejyunus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 9, pl. 1v,
fig. 9; Obs., II, 1838, p. 9, pl. iv, fig. 9 —HANteEy, Biv. Shells,
1843, p. 199, pl. xx, fig. 47,—Kustrr, Conch. Cab. Unio,
1862, p. 265, pl. xc, fig. 1.—?Sowerby, Conch. Icon., XVI,
T868, pl. Lxviu, fig. 347.

Margarita (Unio) jejunus 1A, Syn., 1836, p. 30; 1838, p. 22.

Maregaron (Unio) jejunus Lea, Syn., 1852, p. 32; 1870, p. 51.

Unio complanatus var. jejunus SIMPSON, Syn., 1900, p. 725.

Unio percoarctatus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 85;
esc aN ocieniar, Vij tSO2) po Soa pl, iin, fe. 200; Obs.,
VIII, 1862, p. 63, pl. 1, fig. 206.—Sowersy, Conch. Icon.,
DOV 1866, ple civ, fie. 277.

Margaron (Unio) percoarctatus Lea, Syn., 1870, p. 51.

Var. quadrilaterus Lea.

Shell decidedly rhomboid; posterior ridge distinctly double,
ending in a well-marked biangulation at the posterior base;
base line generally incurved in old shells. Nacre whitish,
lurid purplish or purple.

Length 71, height 41, diam. 23 mm.

Length 55, height 33, diam. 23 mm.

South and North Carolina; Florida. ?

Type locality, Abbeville District, S. C.; Neuse River, Ral-
eigh, N. C.

Unio squalidus Lea, in part, Pr. Ac. N. Sci. Phila., VII, 1863,
p. 192; Jl.. Ac. N. Sci. Phila. VI, 1866, p. 22; Obs., <a
1867, p. 26.—Stmpson, Pr. U. S. Nat. Mus., XV, 1892, P.
429, pl. LXxtI, fig. 14.

Margaron (Unio) squalidus Lea, Syn., 1870, p. 51.

660 UNIO

Unio quadrilaterus Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p.
192; Jl. Ac: N.cSeis Phila:, Vib 866) p35, {ple phe ee Oss,
XT, 1867, p9; ply figede

Margaron (Unio) quadrilaterus Lea, Syn., 1870, p. 51.

Unio complanatus var. quadrilaterus Simpson, Syn., 1900, p.
72s. ;

Variable in color of nacre and degree of inflation.

UNIO ROSTRUM Lea.

Shell elongated, rhomboid, convex, subsolid, generally full-
est at the posterior ridge; dorsal and basal lines parallel, the
latter incurved ; beaks scarcely infiated or elevated, their sculp-
ture not seen, posterior ridge high, single and angular above,
showing a tendency to become double below, ending at or
very near the base line in a blunt point or biangulation; sur-
face with strong, uneven growth lines; epidermis tawny,
tawny-brown or greenish-brown, sometimes feebly raved,
rather smooth and shining; pseudocardinals rough, double in
each valve, the upper in the right valve small; laterals remote,
straight; beak cavities shallow; muscle scars large and im-
pressed ; nacre whitish or flesh-colored.

Length 98, height 44, diam. 26 mm.

North Carolina.

Type locality, Catawba River, Gaston Co., N. C.

Unto wheatley:. Les, Pr. Ac. N. Sei. Phila, ie57,0.- pase lle
Ac. Ne-Sci. Phila:, V, 1861, p.054, -pl..1, ss 2oo hse ane
Ps 5, pl.a, Nee 200.

Margaron (Umeo) catawhbensis LEA, Syn., 1870, p. 52.

Unio catawbensis SIMPSON, Syn., 1900, p. 725.

Unio rostrum Lea, Pr. Ac. N. Sci. Phila., VIII, 1861, p. 391;
Jl. Ac. Nv Sci. Phila. V, 1862, p. 201, pl. xxix, fig. 270;
Obs.; 1X) 1863s p23, plicexix) fia 27a,

Margaron (Unio) rostrum LEA, Syn., 1870, p. 52.

Unio oblongus Lea, Pr. Ac. N. Sci, Phila., Il, 1872, p. 158;
ji. Ac. N. Set? Phila., V1) 1874, p.052) plesvain nebo
Obs., XIII 1874, p: 56, pl. xvi, ficiese:

.

UNIO 661

An elongated, rhomboid, somewhat arcuate form with a
high posterior ridge and almost shining epidermis. Many of
the shells are almost sulcate.

Unio TUOMEYI Lea.

Shell somewhat elongated, solid, varying from subrhomboid
to nearly elliptical, subcompressed to subinflated, inequilateral ;
beaks scarcely elevated or inflated, their sculpture not seen;
dorsal line curved ; basal line rarely incurved, generally straight
or rounded; posterior ridge well developed, single and often
angular above, often becoming feebly and narrowly double
below, ending behind in a point or narrow biangulation below
the median line; surface usually rather smooth; epidermis
tawny to brownish, often more or less rayed, smooth and
shining; left valve with two ragged pseudocardinals and two
laterals ; right valve with one pseudocardinal, sometimes with
a faint one above it, and one lateral; beak cavities shallow ;
muscle scars impressed; nacre generally tinted purple.

Length go, height 46, diam. 25 mm.

Length 77, height 41, diam. 21 mm.

North Carolina to Alabama.

Type locality, Abbeville District, S. C.

Unio tuomevi Lua, Tr. Am. Phil. Soc., X, 1852, p. 256, pl. X11,
fig. 4; Obs., V, 1852, p. 12. pl. x11, fig. 4.—SimPson, Syn.,
1900, p. 726.

Margaron (Unio) tuomeyi LEA, Syn., 1852, p. 33; 1870, Pp. 53.

Unio barrattii Lea, Tr. Am. Phil. Soc., X, AS p: 256, pl. x11,
feos Ops V 1852; sp. 12, pl: xi, hg. 5.

Margaron (Unio) barrattii Lea, Syn.. 1852, p. 37; 1870, p. 245.

Unio barrotti Ptrt., Conch. Sam., ILI, 1890, p. 145.

Unio pullatis Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 262.

Unio pullatus Lea, Jl. Ac. N. Sci. Phila., IV, 1858, p. 57, pl.
vin, fig. 39; Obs., VI, 1858, p- 57, pl. vin, fig. 39.—KustEr,
Conch. Cab. Unio, 1871, p. 247, pl. Lxxxtt1, fig. 3—SoweEr-
By, Conch. Icon., XVI, 1868, pl. Lxvi, fig. 335.

Margaron (Unio) pullatus Lea, Syn., 1870, p. 60.

662 UNIO

Umio' sublatus ea, Proc, No Sen Philas, 1G 1857. pe 16e;
jl. Ac. Ni Set. Phila, IV; 1858p: S27 pl: xvi he, Ga Obs,
VI, 1858, p.82ypl: xvi, fig: 62.

Margaron (Unio) sublatus Lea, Syn., 1870, p. 57.

Unio fumatus Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 271;
Jl Ac. N.Sct. Phila., 1V, 1858, p. 88, pl. xvii, tie68) Oss
VI, 1858, p. 88, pl. xvitt, fig. 68.

Margaron (Unio) fumatus Lea, Syn., 1870, p. 52.

Unio wviridiradiatus Lea, Pr. Ac. N. Sci. Phila., III, 1859, p.
154; Ji Ac: N. Ser Phila., TV, 1800,-p. 336,-plarm1, new16r;
©Obs., VIL, p. 18; plume, fis 161.

Margaron (Unio) viridiradiatus Lea, Syn., 1870, p. 46.

Unio viridans Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 170;
ji. Ac. N:-Se1. Phila; TV; 1860, 'p-"337,, pl. wav, fies 162) (@bs,,
V TS 1860)" ps 10. plsmive hor ate:

Margaron (Unio) viridans Lea, Syn., 1870, p. 52.

Umno hallenbeckn Iwas Pr Ac. ON. Ser Phila, dilly 1Ss50,"p:
yo; Jip Aci NoSe. Plilay Ivy 1stomp. 328; pl iin nes sae
Obs:, VIL, 1860;-p. 102plh 1 fees 4e

Margaron (Unio) hallenbecku Vea, Syn., 1870, p. 52.

Umio salebrosus Lea, Pr. Ac. N. Sci. Phila., XI, 1859, p. 170;
ji- Ac N. Sci. Phila, IV 1860; p. 332, ipl, fen 57 Os:
VE 1860 spasiae plsenik, die v7.

Margaron (Unic) salebrosus Lra, Syn., 1870, p. 52.

Unio verutus lea, Pr Ac. No set. Phila:, Ti S50) patie
Jl. Ac: N.-Se1.<Philas, 1V, 1860; pli aim, fie “noes s@lbs-Nalle
1600, p: 17, pl. Lim, fic. 160:

Margaron (Unio) verutus LEA, Syn., 1870, p. 57.

Unio chathamensis Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p.
Ton; Jk Ac oN. Scr. Philass V5 1666, -pi2ie pl vic ee ae
Obs. Xah 18675 ps'25, ‘pl. vp ie Te!

Margaron (Unio) chathamensis Les, Syn., 1870, p. 53.

Unio hastatus Lea, Pr. Ac. N. Sci. Phila., [1], 1873, p. 423;
JleAc. NecSa@r Phila.,. Villy 18745 piis6,. (pls sais eas ae
Obs XT 21874; p: 60, plc xxeie oan

Unio dooleyensis Lea, Pr. Ac. N. Sci. Phila., III, 1873, p. 424;
JL, Ac. N. Sei Phila., Vill, 18740%p.ib4, pl oc, tie oor
Obs.,, XIII, 2874, -p. 68, pl xx, aie. bo:

UNIO 663

Unio invenustus Lea, Pr. Ac. N. Sci. Phila., III, 1873, p. 424;
fieAc IN sciv Phila. VII, 13874, p. 66, pl. xxi, hg. 62;
Ops. Sell 1674, p. 70; pl. xxi, fig. 62.

Unio gesnerti Lea, Pr. Ac. N. Sci. Phila., III, 1874, p. 424; Jl.
Wee Ne-Ser enitas, V UL 1874, p05, pl. xxl, hg. 61; Obs.,
XIII, 1874, p. 60, pl. xxu, fig. 61.—Sowrrsy, Conch. Icon.,
XVI, 1868, pl. Lxxx1y, fig. 446.

An abundant and somewhat variable form. I have thrown
together under the name Unio tuomeyi a number of so-called
species, some of which seem to be absolutely identical. In
general this form is somewhat elongated, subcompressed or
only moderately inflated, and it has a rather smooth, shining,
though not brilliant, brownish, rayed or rayless epidermis. It
is not so rhomboid as rostrum, is rarely arcuate. is not so
sulcate as that form and does not have quite so high a pos-
terior ridge. The epidermis is rarely a little roughened.

UNIO OCMUI,CFENSIS J,ea.

Shell usually long ovate or elliptical, rarely subrhomboid,
convex or subinflated, solid, inequilateral; beaks not full or
high, their sculpture not observed ; posterior ridge full, round-
ed, sometimes double behind, ending at or below the median
line in a blunt point or biangulation; anterior end often sub-
truncate; surface with irregular growth lines; epidermis dark
ereenish-brown to almost black, lighter and rayed in the young
shell: left valve with two strong, ragged pseudocardinals, and
two heavy laterals; right valve with one pseudocardinal, often
with vestiges of one in front and another behind it, with one
lateral; muscle scars large, impressed; beak cavities shallow ;
nacre lurid purplish, somewhat shining.

Length ro4, height 51, diam. 32 mm.

Georgia.

Type locality, Little Ocmulgee River, Lumber City, Ga.

Unio ocmulgeensis Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 38;
jl. Ac. N. Sci. Phila., V, 1862, p. 95, pl. xiv, fig. 243; Obs.,
VIII, 1862, p. 99, pl. xiv, fig. 243—Simrson, Pr. U. S. Nat.
Mus., XV, 1892, p. 424, pl. Lxvu, fig. 5; Syn., 1900, p. 727.

Marzaron (Unio) ocmulgeensis.LYA, Syn., 18

664 UNIO

This species has more the form of a member of the buckleyi
group than of that of the complanatus group, but it has the
nacre and epidermis of the latter. It is duller colored than the
average manifestation of the ftiomeyi combination, and is
more nearly elliptical or ovate than that species.

UNIo aguiuus Lea.

Shell elongated, nearly evenly elliptical, compressed, rather
thin to subsolid, inequilateral ; beaks low, subcompressed, their
sculpture numerous strong ridges which are curved up behind,
the sculpture extending well on to the disk; posterior ridge
distinct though not high, subangular, scarcely double, ending
behind in a point just below the median line; above this point
there is a short, oblique subtruncation and on the dorsal slope
there are two or three faint radiating ridges ; growth lines un-
even; epidermis dirty greenish or greenish-brown, scarcely
rayed, dull; pseudocardinals rough, subcompressed; laterals.
nearly straight, two in the right valve and a somewhat double
one in the left; muscle scars shallow; nacre bluish-white to.
purplish, rather bright.

Length 65, height 30, diam. 16 mm.

South Georgia and northern Florida.

Type locality, Flint River, Macon and Chattahoochee River,
Roswell, Ga.

Unio aquilus Lea, Pr,.Ac..N, Sei. Phila, [X, 98575 p. 17230
AcoN, Sct. Phila; V,18sS, ps 02, ple ome 72) Ops anal
1858, p. 92, pl. xx, fig. 72.—Simpson, Syn., 1900, p. 727.

Margaron (Unio) aquilus Lea, Syn., 1870, p. 60.

The disk is often ornamented by a number of faint, almost
vertical, corrugations, which sometimes become subnodulous.
It is smaller, more compressed, thinner and duller colored than
U. ocmulgeensis. There are sometimes a few dark rays on the
dorsal slope.

UNIO ICTERINUS Conrad.

Shell oblong, subelliptical or subrhomboid, convex, solid, in-
equilateral; beaks moderately full and elevated, their sculpture
a number of strong concentric ridges; posterior ridge prom-

UNIO 665

inent, somewhat double, ending behind in a narrow faint bian-

gulation at or below the median line; surface nearly smooth ;

epidermis greenish-yellow to tawny or tawny-brown, usually
showing dark rest marks, scarcely rayed, shining; pseudocar-
dinals subcompressed to solid, rough; laterals long, curved;

muscle scars large, impressed; nacre white, often silvery, a

little thicker in front.

Length 103, height 57, diam. 34 mm.

Length 87, height 45, diam. 26 mm.

North Carolina to Georgia.

Type locality, Savannah River, Augusta, Ga.

Unio icterinus Conrap, New F. W. Shells, 1834, p. 41, pl. v1,
fig. 5; Monog., IV, 1836, p. 39, pl. xviul, fig. 2—CHENU,
Bib. Conch., 1st ser., III, 1845, p. 20, pl. 1, fig. 5—S1IMPson,
Syn., 1900, p. 727.

Unio fuliginosus Lea, Pr. Am. Phil. Soc., V, 1845, p. 164; Tr.
Mii, Pht 0G, <as.0 FOS nih, 705) PLavil, oS: 7193 .Obs:,. TV,
1848, p. 52, pl. vu, fig. 19.

Margaron (Unio) fuliginosus Lea, Syn., 18
53:

Unie cvratus es, Pre Ac) N: Scie Phila.,. VII, 1863, -p. 193;
Peace Nese: iil Nek sEGOO, py 23. pl. Vil, fg. .21 > Obs:,
MI 1867; p27, pl. :Vil, fis: 27.

Margaron (Unio) curatus Lea, Syn., 1870, p. 46.

Cen dats. bese rs Acs Ne pei. Philax; X11; 1868, p. 161;
jhe Ac Ne sen Phila) VI._.1868, p: 200, pl. xinv,. fie. 3; Obs.,
MIE 1809, p50; ple xiv, fie. .3:

Margaron (Unio) datus LeA, Syn., 1870, p. 45.

Unio vatus Parer, Conch. Sam., III, 1890, p. 172.

Unio cuspidatus Lea, Pr. Ac. N. Sci.- Phila., II, 1872, p. 159;
eee Serer iva, Ne orem. 43. pl) xiv, fis. 40;
Obs., XITI, 1874, p. 47, pl. xiv, fig. 40.

Unio curcaius ex, Pr. Ac: N. Set, Phila., IJ, 1872, p. 159;
fi Seo NS sce Phila, Vill tea, p38, pl. x11, fig. 35;
Obs. XT, 16745 -p. 42, pl. xi he. 35.

Unio subsquamosus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p.
iGo, fh AG oN. pcis Pilla Vy ile 7A, p: 47, pl. Xvi, fig.-455
Obs., XIII, 1874, p. 51, pl. xvi, fig. 45.

52, p. 33; 1670np-

666 UNIO

Under this name, Unio icterinus, | have united a number of
nominal species, none of which possess any very striking char-
acters. In general the form is oblong, elliptical or subrhom-
boid, and not much inflated; the shell is solid; the epidermis
smooth, shining, and some shade of tawny color. It is a more
solid species than errans and it has a different texture and
color from twomeyi, being more waxy.

UNIO CUVIERIANUS Lea.

Shell elongated, elliptic rhomboid, subinflated or convex,
solid, inequilateral; beaks slightly elevated; posterior ridge
prominent, subangulate above, becoming somewhat double be-
low, ending above the base in a faint biangulation; surface
with irregular, concentric sculpture, more or less smooth and
shining; epidermis tawny-brownish, sometimes tinged with
green; pseudocardinals double in each valve, the anterior one
of the right valve smali, the others stumpy; laterals curved;
muscle scars large, impressed; nacre white or purplish, rather
dull.

Length too, height 57, diam. 36 mm.

Type locality, Washington County, Georgia.

Unio cuvierianus Lea, Tr. Am. Phil. Soc., [X, 1852, p. 263,
plo xvE fie.-165 Obs:, V5 18525 py 10) plo xvi; fie TO:

Margaron (Umo) cuvierianus Lea, Syn., 1852, p. 32; 1870,
posi:

Unio icterinus (part) SIMPSON, Syn., 1900, p. 727.

In the Synopsis I placed this in the synonymy of U. tcter-
imus Conrad, and it approaches that species quite closely. Re-
cent study has, however, led me to believe that it may be dis-
tinct. It is somewhat more elliptical than Conrad’s shell, is
more inflated and generally rather less elongated.

UNIO ROANOKENSIS Lea.

Shell large, elongated, subrhomboid or sometimes subobo-
vate, compressed or subcompressed, inequilateral, subsolid or
solid; beaks low, subcompressed, their sculpture apparently a
few longitudinal corrugations; posterior ridge moderately de-

UNIO 667

veloped, double, ending behind in a wide biangulation at and

below the median line; anterior end often cut away, below,

rounded; basal line straight, rarely a little incurved, some-
times quite full behind the middle; surface generally rough,
with uneven growth lines; epidermis dirty tawny or tawny-
green and faintly rayed in young shells, becoming reddish-
brown or black in old specimens; pseudocardinals often blur-
red, low and strongly cross striate; laterals remote, heavy,
one in the right valve and two in the left; beak cavities shal-
low ; dorsal scars in a row under the hinge plate; muscle scars
shallow ; the anterior ones rough; nacre dirty purplish, often
thicker in front.

Length 143, height 67, diam. 35 mm.

Length 140, height 68, diam. 43 mm.

Length 106, height 55, diam. 25 mm.

Connecticut River at Northampton, Massachusetts; south
to the Savannah River, Georgia.

Type locality, Roanoke River, between Norfolk and ‘Tar-
boro, N. C.; Altamaha River, Ga.

Margarita (Unio) roanokensis Les, Syn., 1836, p. 30; 1838,
pe 20.

Unio roanokensis LEA, Tr. Am. Phil. Soc., VI, 1838, p. 27, pl.
vir, fie: 21; Obs., Il, 1838, p: 27, pl. viii, fig. 21—CHENU,
Ill. Conch., 1858, pl. xx, figs. 6, 6a, 6b—Sowerpy, Conch.
Icon., XVI, 1868, pl. Lxvi, fig. 341.—SiImMpPSoN, Syn., 1900,
pe 720.

Margaron (Unio) roanokensis Lea, Syn., 1852, p. 32; 1870, p
Cie .

Unio macer Lea, Pr. Ac. N. Sei. Phila., I, 1857, p. 86; Jl. Ac.
Niet semua. Vil; 1662, p. 2027p xxix, fig: 271 5 Obs., IX,
1803; p: 24 spk BRIX, fic. 277-

Margaron (Unio) macer Lea, Syn., 1870, p. 51.

Unio -latus gpa Pr Ac, N.ocie Phila:, III; 1859, p.. 171; Jl.
Ac NaSsc. Pinas IY. 18605 px sa4.<pl. Lit, fig.-159; Obs.,
MILL, 1860;.p.-16, pl. Tins fie E50,

Margaron (Unio) latus Lea, Syn., 1870, p. 57.

1668 UNIO

A large, elongated, compressed form, which approaches
hopetonensts, but is less inflated and less rhomboid than that
species and has a duller nacre. The young shells of this spe-
cies never have that peculiar olive-green tint found on the
young of hopetonensis.

Var. northamptonensis Lea.

Shell subelliptical or subovate, rather long, compressed, the
biangulation often a little higher up than in the type ; epidermis
tawny or tawny-greenish, generally rayed in old ones; nacre
whitish or dirty purplish.

Length 110, height 58, diam. 24 mm.

Type locality, Connecticut River at Northampton, Spring-
field and below Hartford, Mass.; Neuse River, N. C.

Unio northamptonensis ma, Pr. Ac. N. Sci. Phila., V, 1861,
p.. 3902; Jl. Ac: N.-Sci: Philas- Ve1S62) p90. pla cyano
260 ;Obs:, LX, 1863.-p: 12; ply xxv nties 2ae:

Margaron (Unio) northamptonensis Lea, Syn., 1870, p. 51.

Unio roanokensis var. northamptonensis SIMPSON, Syn., 1900,
pu 728:

This agrees so closely with specimens of roanokensis that |
have been induced to consider it as a variety of that, notwith-
standing its widely separated distribution. I have before me
roanokensis from the Savannah River, named by Dr. Lea and
belonging in his collection, that agree in all essential characters
with sxorthamptonensis from the type locality. Both have the
same general form, the inflation behind, the middle of the base
and the same color within and without. The variety has the
same low, ill-defined, strongly cross-striated pseudocardinals
as the type.

UNIO HOPETONENSIS Lea.

Shell rather large, subrhomboid, a little narrowed in front,
subcompressed to subinflated, the greatest diameter being at
the posterior ridge, in front of which the shell is wedge-shaped ;
posterior ridge well developed, single and narrowly rounded
above, double below, ending in a wide biangulation at or above

UNIO 669

the posterior base; base line nearly straight, sometimes pro-

duced a little towards the posterior end; surface with fine, un-

even growth lines; epidermis dirty or brownish-green and
sometimes rayed in young shells, brown or blackish in old
shells, scarcely shining; pseudocardinals smail and low, gen-
erally cross striated, often ill-defined; there are two short lat-
erals in the left valve and one in the right ; beak cavities shal-
low ; muscle scars impressed ; nacre flesh-color or purplish, gen-
erally bright and iridescent behind.

Length 120, height 65. diam. 38 mm.

Length 96, height 43, diam. 28 mm.

Length 135, height 65, diam. 33 mm.

Length 140, height 75, diam. 43 mm.

Georgia, in streams flowing into the Atlantic ; Santee Canal,

South Carolina.

Type locality, Hopeton, near Darien, Ga.

Unio hopetonensis Lea, Tr. Am. Phil. Soc., VI, 1838, p. 29,
pl. 1x, fig. 24; Obs., II, 1838, p. 29, pl. rx, fig. 24.—HANLEy,
Biv. Shells, 1843, p. 198, pl. xx, fig. 21 —CHENu, Il. Conch.,
1858, pl. xx, figs. 5, 5a, 5b—Kuster, Conch. Cab. Unio,
1861, p. 196, pl. Lxit, fig. 1.—Sowersy, Conch. Icon., XVI,
1868, pl. Lxvil, fig. 349.—Simpson, Pr. U. S. Nat. Mus.,
DeVe AGO2) p.4i2, pl ian, fis ss ta, iis: 1; Syn., 1900, p. 728.

Margarita (Unio) hopetonensis Lea, Syn., 1836, p. 30; 1838,
p21.

Margaron (Unio) hopetonensis Lea, Syn., 1852, p. 323; 1870,
pel
A rather fine, large species with a peculiarly tinted epider-

mis and usually rich, brilliant nacre. In a great many speci-

mens the pseudocardinals are feebly developed and not well
separated, and are decidedly cross-striated.

UNIO LIVINGSTONENSIS Lea.

Shell subrhomboid, being narrower in front than behind,
thin, not inflated, its greatest diameter being at the posterior
ridge and in front of this it is wedge-shaped, inequilateral ;
beaks low, somewhat compressed, their sculpture not seen:

670 UNIO

posterior ridge imperfectly double, the main ridge ending be-
hind at the base of the shell, above this the outline is irregularly
curved up to the dorsal line; surface with uneven growth lines ;
epidermis of different shades of greenish-brown, cloth-like
when fresh; pseudocardinals small, double in the left and sin-
gle in right valves; laterals remote, delicate, curved; muscle
scars shallow ; nacre bluish or greenish-white to purplish.

Length 68, height 40, diam. 22 mm.

North Carolina to Georgia.

Type locality, Livingston’s Creek, Brunswick Co., N. C.
Unio liingstonensis Lea, Pr. Ac. N. Sci. Phila., VII, p. 192;

jl. Ac. IN. Set; Philaz Vil, 1860;"p ei p lr io see Oboe

XI, 1867, p. 18, pl. 1v, fig. 11.—Simpson, Syn., 1900, p. 720.
Margaron (Unio) livingstonensis La, Syn. 1870, 9p. 52:

Quite a distinct species for a member of the complanatus
group. So far as I have seen the shell is always rather
thin and narrower in front, its greatest inflation is at the pos-
terior ridge and from that point forward it is wedge-shaped
when viewed from above. The wide ‘posterior end is bounded
by an uneven curved line, which shows one or two faint angles.
The epidermis is rough, dark and cloth-like.

UNI0 INUSITATIS Lea.

Shell subrhomboid, higher behind than in front, inequilat-
eral, rather thin, scarcely inflated, its greatest diameter being
at the posterior ridge; beaks moderately full and elevated,
their sculpture not seen; posterior ridge high, subangulate,
ending below in a blunt point at the base of the shell; surface
with irregular, concentric sculpture; epidermis tawny-brown-
ish and greenish, rather bright; pseudocardinals small, sub-
compressed, double in the right valve and single in the left;
laterals remote, short; muscle scars shallow, smooth; nacre
lurid, purplish, brownish or coppery, brilliant and iridescent
behind.

Type locality, Swift Creek, below Macon, Georgia.

UNIO 671

Unio musitatis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 171;
(iNew oci Phila, LV, 1860, p..333, pl. ni, fig. 158; Obs.,
VIII, 1860, p. 15, pl. Lm, fig. 158.—Simpson, Syn., 1900, p.
720.

Margaron (Unio) inusitatus Lea, Syn., 1870, p. 51.

Unio msitatus B. H. Wricut, Check List, 1888.

I do not know what to do with this. I have only seen the
type, and it appears to be injured. It is shaped something like
U. livingstonensis, but it has a higher, single posterior ridge.
The epidermis and nacre are much brighter than they are in

lizingstonensis.

UNIo DIFFERTUS Lea.

Shell irregularly rhomboid, a little higher behind, inequilat-
eral, subsolid, its greatest diameter being at the posterior ridge ;
beaks neither full or high, their sculpture apparently irregular
corrugated ridges; posterior ridge high, subangulate, inclined
to be double below, ending below the median line in a very
faint biangulation; base line curved up a little behind, nearly
straight the rest of its length; surface with uneven growth
lines, nearly smooth at the middle of the disk, strongly sulcate
in front; epidermis tawny or tawny-green, scarcely rayed,
showing the dark, widely spaced rest marks; pseudocardinals
subcompressed, elevated, double in each valve, the upper one
in the right valve small; laterals high, granular; beak cavities
impressed ; muscle scars well marked; nacre flesh-color, pur-
plish-pink and iridescent behind.

Length 84, height 47, diam. 30 mm.

Savannah River, Georgia.

Type locality, Georgia?

Umovaunertus ies Pr Ac. N.sct iila., 11; 1872, p. 158; Jl.
Neon. sem Eola VL 1874. py a2. pl. xiv, fis 39; ‘Obs..
XITI, 1874, p. 46. pl. xtv, fig. 39.—Srmpson, Syn., 1900, p.
720.

I cannot connect this with any other form. It is a smooth
almost waxy, rather attractive shell, evidently of rapid growth
as the largest specimen seen shows only two rest marks. The
nacre is rather soft and silvery, of a decidedly rich tint behind.

672 UNIO

UNIo PLANTII Lea.

Shell nearly elliptical or a little obovate, compressed, sub-
solid, inequilateral ; beaks apparently low and compressed, their
sculpture not seen; posterior ridge low, ending behind just
below the median line; anterior end a very little narrowed,
rounded; posterior end feebly subtruncated above, rounded
below; basal and dorsal line curved; surface with irregular,
concentric sulcations; epidermis greenish-brown, subshining ;
pseudocardinals small, roughened, double in each valve, the
upper in the right valve small; laterals remote; muscle scars
impressed; nacre lurid purplish, iridescent behind; pallial line
crenate.

Length 93, height 56, diam. 26 mm.

Type locality, Flint River; near Macon, Georgia.

Unio plantu Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 171; Jl.
Ac. N. Sci? Phila... V5 1859, 2-102; pl ext, fies Zon @ass
VII, 1859, p. 10, pl. xx1, fig. 76—Sowerrsy, Conch. Icon.,
XVI, 1868, pl. Lxxxvil, fig. 473.—SIMPSON, Syn., 1900, p.
729. =

Margaron (Unio) plantii Lea, Syn., 1870, p. 43.

The only shell seen, the type, appears to be a little injured
behind. It is a peculiar disk-like form, nearly evenly elliptical,
the least trifle rhomboid, and unevenly sulcate.

UNIo stRUMOSUS Lea.

Shell subrhomboid, rather short, slightly inequilateral, sub-
solid, scarcely inflated; beaks apparently neither full nor high ;
posterior ridge full, narrowly rounded, ending behind in a
blunt point at or near the base; surface with uneven growth
lines; epidermis dirty yellowish-brown or greenish-brown, sub-
shining ; pseudocardinals rather strong, ragged, double in the
left valve and single in the right, laterals short, heavy, much
curved; dorsal cavities compressed; muscle scars well marked :
nacre dirty, lurid whitish.

Length 68, height 45, diam. 24 mm.

Type locality, Yadkin River, North Carolina.

UNIO 673

Unio strumosus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 158;
Wie 2e7a ep. 4esenjl ce Nooct Phila “Vill, 1874, p. 37,
pens, ue. 55; Obs... Xl, 1874, p. Ox, pl.. xix; fig. 55—
SIMPSON, Syn., 1900, p. 729.

Appears to be near to U. dorsatis, but is smoother ; it scarce-
ly has a double posterior ridge, and its beaks and posterior
ridge are not so elevated.

UNIO PuRUS Lea.

Shell between subrhomboid and _ subelliptical, somewhat
elongated, convex, inequilateral; beaks not much elevated or
inflated, their sculpture not seen; posterior ridge high, round-
ed, curved up in the middle, ending in a rounded point near
the base of the shell; surface with uneven growth lines; epi-
dermis dirty yellowish-green or dirty brownish-green, rather
smooth in young shells, becoming dull in old ones; pseudo-
cardinals low, solid, rough, double in both valves; laterals
curved, strong, remote; muscle scars round, distinct; nacre
purplish, a little thicker in front.

Length 76, height 42, diam. 25 mm.

Type locality, Neuse River, near Raleigh, North Carolina.
Oniorpirds Teserr Ac. N. Se: Phila. 1, °1858, p. 41; Jl.

Ac. N. Sci. Phila., V, 1862, p. 61, pl. 1v, fig. 209; Obs., VIII.

1862, p. 65, pl. Iv, fig. 209.—Simpson, Syn., 1900, p. 720.
Margaron (Unio) purus Lea, Syn., 1870, p. 43.

A rather neat, finely formed species, which does not seem
to connect with anything else. The outline is between rhom-
boid and elliptical, the posterior ridge is rounded and curved
up in the middle.

UNIO SUBNIGER (Lea).

Shell subrhomboid, scarcely subsolid, convex, inequilateral ;
beaks apparently neither full nor high; posterior ridge strong,
subangular or narrowly rounded, curved up in the middle,
ending behind in a blunt point near the base line; base line
incurved a little; surface with decided concentric sculpture ;
epidermis blackish, scarcely shining; pseudocardinals small,

674 UNIO

sharp, ragged; laterals delicate, curved; muscle scars large,

shallow ; beak cavities shallow ; nacre bluish or milky-white.
Length go, height 52, diam. 28 mm.

Georgia.
Type locality, Flint River, Macon, Ga.

Unio subniger Lea, Pr: Ac. Ne sei. Philas 1 X= 1857; pa a72e
Jl Ac. NoSei.:Phila., TV 1859, 1p: 160,.pl: xx ties yon Ons
VII, 1850, p. 14, pl. xxu, fig. 79—SiIMpson, Syn., 1900, p.
730.

Margaron (Umo) subniger LEA, Syn., 1870, p. 52.

This shell is shaped much like forms of U. complanatus,
but the posterior ridge curves up in the middle and it is covered
with decided concentric sculpture.

UNIO BURKENSIS Lea.

Shell oblong, subelliptical or subrhomboid, thin, subcom-
pressed, inequilateral ; beaks neither full nor high, their sculp-
ture not seen; posterior ridge moderately full, double, ending
behind in a biangulation at and below the median line; base
line nearly straight, anterior end subtruncate above; surface
slightly marked with incremental and faint radiating sculpture ;
epidermis dull dirty green, showing vestiges of rays, subshin-
ing ; pseudocardinals small, sharp, nearly smooth, compressed,
one in the left valve and two in the right; laterals delicate,
straight ; muscle scars shallow ; nacre lurid purplish, iridescent
behind.

Length 70, height 34, diam. 17 mm.

North Carolina; south to Georgia.

Type locality, Buckhead Creek, Burke Co., Ga.

Unio burkensis Lea, Pr. Ac. N. Sci. Phila., TI, 1859, p. 112;
JL Ac. Ny, Seis Phila. IV; 1850, p. 205, pL sexviag ees,
Obs., VII, 1850, p. 33, pl. xxv, fig. 95.—Srmpson, Syn.,
1900, p. 730.

Margaron (Unio} burkensis Lea, Syn., 1870, p. 60.

Unio dissimilis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 161;

Ii., Ac. Ne Sei Phila., VILL a8745p. 53, pl. ora ee

Obs., XITI, 1874, p. 57, pls xvmu, fig. 52.

UNIO 675

Very close to U. nawiculoides and probably only a variation
of it. It is higher in proportion than that species, the poste-
rior ridge is not so high and it is a little less concentrically
sculptured.

UNIO OBLATUS Lea.

Shell subrhomboid, rather solid, convex, inequilateral ; beaks
apparently not full or high; posterior ridge high, rounded,
becoming feebly double below, ending behind in a faint biangu-
lation below the median line; anterior end round; base nearly
straight ; dorsal slope obliquely subtruncated ; surface thrown
up into low, concentric ridges at the dark rest marks, otherwise
nearly smooth; epidermis dark olive, smooth and shining; left
valve with two stumpy pseudocardinals and two club-shaped
laterals ; right valve with two pseudocardinals, the upper small,
with one lateral ; anterior scars impressed ; posterior scars shal-
low ; nacre dirty flesh-color; nacre thicker in front.

Length 65, height 32, diam. 18 mm.

Type locality, Long Creek, Gaston County, North Carolina.
Unio ablatus Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 193.
Unio oblatus Lea, Jl. Ac. N. Sci. Phila., VI, 1866, p. 13, pl. rv,

fig. 10; Obs. XI, 1867, p. 17, pl. v, fig. 10—SIMPson, Syn.,

TQO0, Pp. 730.

Margaron (Unio) oblatus Lea, Syn., 1870, p. 60.

Another puzzling nondescript. The surface of the only
authentic shell I have seen, the type, is thrown up into low,
concentric ridges at the rest marks, which are dark and nar-
rowly spaced. The epidermis is dark olive, but shining; the
nacre is much thickened in front.

UNIO ERRANS Lea.

Shell elongated, subrhomboid or subelliptical, compressed
to convex, inequilateral; subsolid or rather thin; beaks low,
not inflated, their sculpture a number of strong ridges, which
run nearly parallel with the growth lines and are heavier
where they cross the posterior ridge ; posterior ridge moderate-
ly developed, inclined to be double below, ending behind in a

676 UNIO

faint biangulation between the median line and base; surface
nearly smooth or with a few uneven growth lines; epidermis
greenish-yellow to brownish, often feebly rayed; pseudo-
cardinals delicate, subcompressed, double in each valve, the
upper in the right valve feeble; laterals delicate, nearly
straight ; muscle scars scarcely impressed ; nacre whitish to pale
brownish-purple, iridescent behind.

Length 74, height 35, diam. 22 mm.

Length 72, height 35. diam. 17 mm.

Type locality, Tobesaufke Creek, near Macon, Georgia.
Unio paliatus RAVENEL, letter—Conrap, Pr. Ac. N. Sci.

Philar, Vie 1853. pa2s4:

Margarita (Umo) paliatus Lea. Syn., 1836, p. 31; 1838, p. 22.

Margaron (Umio) pahatus Lea, Syn., 1852, p. 33; 1870, p. 53.

Unio palliatus RAVENEL, Cat., 1875, p. 57.

Umo .errans. Lea, Pr. Ac. N. Sci Phila. VIII, 1856, p. 2625
Why Ac-N.? Sct. Phila. [Vj 2S58.0p) 60; plod wie ers Olne.
VI, 1858, p. 60, pl. 1x, fig. 42.—SIMPSON, Syn., 1900, p. 730.

Margaron (Unio) errans, LeA, Syn., 1870, p. 52.

Unio vicinus Lea, Pr. Ac. N. Sci. Phila., WIII, 1856, p. 262;
jl. Ac. N. Sci,- Phila, 1V., 1858; ‘p: 61, pk ax, hes; Obs.
VI, 1858; p. 61, pl ix, fis. 43:

Margaron (Umo) vicinus Lea, Syn., 1870, p. 52.

A rather delicate, subrhomboid or sometimes subelliptical,
compressed to convex, form with no striking characters. It
is usually nearly smooth and shining. It is a much less robust
shell than U. tuomeyi.

Dr. Lea credits U. paliatius to Ravenel’s letter, (Syn., 1836),
and Ravenel, (1875), ascribes it to Lea, but neither ever de-
scribed it so far as I know.

UNIO SAGITTIFORMIS Lea.

Shell elongated, rhomboid, compressed, subsolid, inequilat-
eral: beaks slightly elevated, but not inflated, their sculpture
consisting of strong, longitudinal, somewhat corrugated ridges ;
posterior ridge well developed, ending in a somewhat produced
point near the base of the shell; dorsal slope very obliquely

UNIO 677

subtruncated ; base line nearly straight ; anterior end slopingly
cut away helow, rounded above; surface having more or less
concentric sculpture, the sulcations strong at the anterior end:
epidermis greenish-yellow, rayed, subshining; left valve with
two subcompressed pseudocardinals and two club-shaped later-
als; right valve with. two pseudocardinals, the upper small, and
one lateral; muscle scars well marked, the posterior elongated ;
nacre pale lurid brown.

Length 69, height 30, diam. 15 mm.

Type locality, Oconee River, Athens, Georgia. Also Abbe-
ville, South Carolina.

Unio sagittiformis Lea, Tr. Am. Phil. Soc., X, 1852, p. 277,
Pi socmy 1 35 Obs, V, 1852, p. 63, pl xxi, fig. 35.—
SOWERBY, Conch. Icon., XVI, 1868, pl. xcu, fig. 499—
SIMPSON, Syn., 1900, p. 731.

Margaron (Unio) sagittiformis Lea, Syn., 1852, p. 37; 1870,
“pba.

A peculiar shell, which may be diseased, yet it appears to
be normal. The posterior point is much drawn out, the ante-
rior base is decidedly cut away below. ‘The species might be
placed in the fisherianus group with about as much propriety
as in this.

UNIo DISPALANS B. H. Wright.

Shell subrhomboid, rather thin, subcompressed to convex,
inequilateral; beaks not inflated or elevated, their sculpture
consisting of strong ridges, which run parallel with the growth
lines; posterior ridge well developed, narrowly rounded or
angled, ending behind near the base in a blunt point or a fee-
ble, narrow biangulation; anterior end a very little narrower,
rounded ; surface with uneven growth lines; epidermis yellow-
green and faintly rayed in young shells, brown, rough and
cloth-like in old ones; pseudocardinals small, compressed, dou-
ble in each valve, the upper in the right valve small; laterals
delicate, curved ; muscle scars shallow; nacre dirty coppery.

Length 65, height 35, diam. 18 mm.

Type locality, Suwanee River, Florida.

OV
“NI
Ce

UNIO

Unio dispalans B. H. Wricu'r, Naut. XIII, 1899, p. 50.—
Simpson, Pr. Ac. N. Sci. Phila., 1900, p. 80, pl. 1, fig. 9;
Syn., 1900, p. 736.

A puzzling form which has no decided characters, yet which
does not seem to equal anything else. Since seeing the type
shell I have examined other material and rather incline towards
placing it in the complanatius group.

Unio ANGUSTATUS Lea.

Shell elongated, subrhomboid or subelliptical, subcompressed
to scarcely inflated, the greatest diameter being at the poste-
rior ridge; thin to subsolid, inequilateral; beaks scarcely ele-
vated or inflated, their sculpture being strong ridges running
nearly parallel with the growth lines; posterior ridge well
developed, angulated, more or less double, ending behind in
a slight biangulation at or below the median line; surface
with decided concentric sculpture; epidermis olive in young
shells, nearly black in old ones, rather dull; pseudocardinals
compressed, double in each valve, the upper one in the right
valve small; laterals long, somewhat club-shaped ; muscle scars
shallow ; nacre purplish-brown.

Length 98, height 42, diam. 23 mm.

Length 74, height 30, diam. 19 mm.

South Carolina to western Georgia.

Type locality, Cooper River, S$. C.

Unio angustatus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 114, pl.
xvu, fig. 43 ; Obs., I, 1834, p. 124, pl. xvut, fig. 43 Conran,
Monog., XI, 1838, p. 98, pl. Liv, fig. 2—HaAntEy, Biv. Shells,
1843, p. 204, pl. xxu1, fig. 25 —CuEnu, Ill. Conch. 1858, pl.
XIV, figs. 1, Ta, 1b.—Kuster, Conch. Cab. Unio; 1801)" p
178, pl. Lv1, fig. 4.—Sowersy, Conch. Icon., XVI, 1868, pl.
LXXII, fig. 372.—SIMPpsON, Syn., 1900, p. 731.

Margarita (Unio) angustatus Les, Syn., 1836, p. 35; 1838, p-
23.

Margaron (Unio) angustatus Lea, Syn., 1852, p. 36; 1870, p.

cs

We

UNIO 679

Unio extensus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 31; JI.
me. ON. pet. Phila. DY, 1858, p.\68, pl. xi, fig: 49; Obs., VI,
1868, p. 67, pl. xu, fig. 40.

Margaron extensus Lea, Syn., 1870, p. 60.

Unio subcylindraceus Lea, Pr. Ac. N. Sci. Phila., III, 1873,
putea eae Ne oe Phila: Vill, 18745"p. 58) plo-xx, fig.
as Obs: el LS 7A, pr 62) ple xx, figy 57.

Much elongated, either subrhomboid or almost elliptical,
with dull dark epidermis and decidedly sulcate sculpture.

UNIO PERSTRIATUS Lea.

Shell elongated, subrhomboid, compressed, subsolid, inequi-
lateral; beaks slightly elevated but not full, their sculpture
consisting of longitudinal bars; posterior ridge well developed,
with a tendency to becoming double below, ending behind near
the base in a rounded point or feeble biangulation; dorsal
slope obliquely truncated ; base line nearly straight ; dorsal line
curved a little; surface with fine, concentric sculpture; epi-
dermis tawny-greenish, or olive, scarcely rayed, covered with
fine, concentric lamella. very dull; pseudocardinals subcom-
pressed, rough, single in the right valve and double in the
left ; laterals straight, delicate; muscle scars large, shallow, the
posterior ones long elliptical; nacre bluish-white, dull.

Length 57, height 24, diam. 11 mm.

Length 72, height 29, diam. 12 mm.

North and South Carolina.

Type locality, Abbeville District, S. C.

Unio perstriatus Lea, Tr. Am. Phil. Soc., X, 1852, p. 255, pl.
xu, fig. 3; Obs., V, 1852, p. 11, pl. xu, fig. 3—SOwErRBY,
Conch. Icon., XVI, 1868, pl. xci1, fig. 500.—Srimpson, Syn.,
1900, p. 731.

Margaron (Unio) perstriatus Lea, Syn., 1852, p. 36; 1870, p.
57-

Unio gracilentus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 85;
ji Ac. N«Se: Phila, V, 1862,.p: 58, pl. m1, fig...205 5 Obs.,
V iti, 1862, p: 62, pl. 111, fig- 205:

Morgaron (Unio) gracilentus Lea, Syn., 1870, p. 60.

680 UNIO

Unio perlatus Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 193:
Jl. Ae. N. SerPhilas Vi; 1866; 9158 pli ive fea Obs:
XG 16673 p.21G; plaiv. ies 122

Margaron (Unio) perlatus Lea, Syn., 1870, p. 60.

A delicate, compressed form, whose surface is finely, con-
centrically striate. U. gracilentus is a little darker, but I do
not think it 1s specifically or even varietally different.

UNIO NAVICULOIDES Lea.

Shell much elongated, subrhomboid, thin, convex, inequi-
lateral; anterior end subtruncated above; base line straight or
a little incurved in the middle; posterior ridge full, double,
the lower ridge the stronger, ending behind in a biangulation
below the median line; beaks apparently low and compressed:
surface distinctly, though not strongly, marked with concen-
tric sculpture ; epidermis dull olive-green, rather dark, scarcely
shining ; pseudocardinals small, nearly smooth, one in the right
valve and two in the left; laterals long, delicate and straight ;
muscle scars small and shallow; nacre dull purplish, iridescent
behind,

Length 75, height 32, diam. 18 mm.

Length 71, height 31, diam. 19 mm.

Length 72, height 33, diam. 21 mm.

Georgia.

Type locality, Buckhead Creek, Burke Co. and Macon, Ga.
Unio naviculoides Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 170;

Jls Acs N. Seis Phila, 1V, 1858.19) 94, pl. <x-hies 74 Obs

VI, 1858, p. o4, pl. xx, fig. 74.—Simpson, Syn., 1900, p. 732.
Margaron (Unio) naviculoides Lea, Syn., 1870, p. 60.

Darker colored, more elongated, more decidedly sulcate and
having a stronger posterior ridge than U. burkensis, but
doubtfully distinct. I have seen only a limited amount of
material of the two forms that I can consider valid.

UnN1I0 sorpipus Lea.

Shell subrhomboid, subelliptical or subovate, convex, sub-
solid, inequilateral; beaks rather full and elevated above the
dorsal line, their sculpture unknown; posterior ridge full, in-

UNIO 681

clined to be double below, ending in a faint, wide biangulation

at and below the median line; surface with irregular growth

lines, sometimes having low, concentric ridges ; epidermis dark
tawny, shaded with green, sometimes faintly rayed; base line
nearly straight; dorsal slope obliquely subtruncated; anterior
end rounded, usually a little narrower than the posterior end;
left valve with low, rather blurred, double pseudocardinals and
two laterals; right valve with somewhat double pseudocardinals
and one lateral; muscle scars distinct; nacre dirty white or
purplish, thicker in front.

Length 62, height 33, diam. 19 mm.

Length 72, height 38, diam. 24 mm.

Type locality, Abbeville, South Carolina. Also Catawba

River, North Carolina.

Unio sordidus Lea, Tr. Am. Phil. Soc., X, 1852, p. 254, pl. XJ,
fig. 1; Obs., V, 1852, p. 10, pl. xu, fig. 1—Srmpson, Syn.,
IQO00, Pp. 732. —

Margaron (Unio) sordidus Lea, Syn., 1852, p. 33; 1870, p. 54-

Unio gibbesianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 254, pl.
mateo Gs nV. LO52)p. £0, pl. Xil, fig. 2.

Margaron (Unio) gibbesianus LEA, Syn., 1852, p. 33; 1870, p.

4.

A form or species with almost no distinguishing characters,

yet I cannot place it with anything else. The type of U. gib-

besianus has the pseudocardinals divided into several denti-

Fal

‘cles, otherwise it agrees with sordidus. The shell varies from
subrhomboid to subelliptical, or subovate, has a dirty tawny,
half shining, greenish epidermis and is considerably thickened
in front.

UNIO SPADICEUS Lea.

Shell rather small, oblong, subrhomboid, subcompressed,
inclined to be solid, inequilateral; beaks apparently not ele-
vated or inflated; posterior ridge feebly double, ending behind
in a biangulation at and below the median line; dorsal slope

obliquely subtruncated; base line faintly emarginate in the
middle, swollen behind that point; surface irregularly striate ;

682 UNIO

epidermis tawny or reddish-brown, with a slight bronzy hue,
shining ; pseudocardinals stumpy, double in each valve; right
valve with one curved lateral ; left valve with two; muscle scars
distinct ; nacre salmon or coppery-tinted, thicker in front.
Length 45, height 23, diam. 14 mm.
Type locality, Mountain stream, North Carolina.

Umo spadiceus Ura, Pro Ac. N. Ser Phila, 10857, p60,
AceNy Sear Phila V >) 1862, 94.55, plat: te. 201 Ops nr
1862, p. 12, pl. 1, fig. 201.—SIMPSON, Syn., 1900, p. 732.

Margaron (Unio) spadiceus Lea, Syn., 1870, p. 48.

A small form, the tvpe of which seems to be adult. It has

a rather solid shell, slightly produced on the base behind the

middle, with a half metallic, tawny-brown or reddish-brown,

shining epidermis and salmon nacre.

UnIo stricosus Lea.

Shell elongated, somewhat arcuate, compressed, solid, in-
equilateral ; basal and dorsal lines nearly parallel; anterior end
rounded ; posterior end feebly subtruncated above, almost even-
ly rounded below ; posterior ridge widely rounded, showing the
faintest trace of biangulation; beaks evidently not raised or
full; surface with delicate but well-marked growth lines; epi-
dermis greenish and shining on the disk, darker and duller
on the border of the shell; pseudocardinals feebly developed,
low, two in the left valve and one in the right ; laterals remote,
not strong; muscle scars well marked; nacre dull purplish-
greenish, iridescent behind, thicker in front.

Length 55, height 24, diam. 13 mm.

Type locality. Chattahoochee River, Columbus, Georgia.
Also Southeast Alabama ?

Unio strigosus Lea, Pr. Am. Phil. Soc., 1, 1840, p. 287; Tr-
Am: Phil Soe! VIL, 1843; -p. 168 pl. este on Ober:
1842, p. 36, pl. rx, fig. 9 —CHENU, Ill. Conch., 1858, pl. xxx,
figs. 6, 6a, 6b.—Srtmpson, Syn., 1900, p. 732.

Margaron (Unica) strigosus Les, Syn., 1852, p. 36; 1870, p. 57.
A curious form, approaching U. lazarus, but more solid

and smoother. Its teeth are but imperfectly developed; the

UNIO 683

nacre is purplish in front and green iridescent behind. Dr. Lea
has placed larger specimens with this from the Little Uchee
River, Alabama, that seems to be different.

Unio stncuLaris B. H. Wright.

Shell rather elongated. subrhomboid or subelliptical, some-
what inflated, a little narrower and rounded in front; inequi-
lateral: base line straight or slightly incurved in the middle,
full behind the middle; posterior ridge full, double, ending be-
hind in a wide, square biangulation ; surface rough, with strong
growth lines; epidermis olive in young shells, reddish-brown
in adult specimens; pseudocardinals stumpy, ragged; laterals
straight; anterior scars impressed; posterior scars shallow;
nacre coppery or purplish.

Length 66, height 33, diam. 22 mm.

Type locality, Spring Creek, Decatur County, Georgia.
Unio singularis B. H. Wricut, Naut., XIII, 1899, p. 75.

The above was accidentally omitted from the Synopsis. It
is something like U/. strigosus, but is much more inflated. I
am doubtful as to its validity, but hardly feel like uniting it
with anything else.

Unio LAZARUS Lea.

Shell elongated, decidedly arcuate, compressed, subsolid,
inequilateral ; beaks slightly elevated, their sculpture consisting
of strong ridges, which follow the growth lines; posterior
ridge low, rounded or faintly biangulate ; dorsal ‘slope oblique-
ly subtruncated; posterior end rounded or feebly biangulate ;
surface covered with irregular growth lines; epidermis green-
ish and shining in young shells, dark burnt-brown and rough
in old ones; pseudocardinals imperfectly developed; laterals
short, remote, not strong: anterior scars rough; posterior
scars faint: nacre purplish in young shells, almost chocolate-
colored in old specimens.

Length 53, height 22, diam. 11 mm.

Type locality, Abbeville district, South Carolina.

684 UNIO

Unio lazarus Lea, Pr. Am. Phil. Soc., V, 1852, p. 251; T'r. Am.
Phil. Soc., XI, 1852: p. 259). ply saw aie. Os Obs a 1ra52,
p. 15, pl. xiv, fig. 9 —Srupson, Syn., 1900, p. 732.

Margaron (Unto) lazarus Lea, Syn., 1852, p. 39; 1870, p. 62.
A curious form, whose relationships are a little doubtful.

It may be only a variety of U. arctatus, but it is more arcuate
than anything I have seen of that species, is not so biangulate
behind, and has less perfect pseudocardinals. It recalls Mar-
garitana, but I have found no pits in the nacre of any of the
shells I have seen. Unio strigosus approaches it in appearance,
but is much more solid and is less arcuate.

Group of Unio downtet.

Shell subtrapezoidal, infiated, solid, truncate and more or
less triangular behind, sometimes swollen in the post-basal
region, with a well-developed posterior ridge; beaks full, their
sculpture not observed; epidermis smooth and shining in the
young shell, becoming duller and roughened when old; hinge
moderately strong; pseudocardinals radial, roughened ; laterals
heavy, somewhat remote, curved; there is a more or less
developed secondary lateral in the right valve; dorsal scars
few, in a row just behind the pseudocardinals, and fully ex-
hibited on the inner edge of the shallow beak cavity; nacre
dull; muscle scars distinct, smooth.

Animal with the marsupium occupying the whole of the
outer gills; inner gills free from the abdominal sac a part of
their length ; palpi rather small ; mantle line thick on the border.
UNIO DOWNIEI Lea.

Shell usually obovate, solid, inflated, inequilateral ; beaks
full and high, no doubt; posterior ridge well developed, angu-
lar above, becoming double below and ending at and below the
median line; anterior end rounded or truncate; dorsal slope
rather high, scarcely truncated ; base line curved and produced
behind the middle; epidermis laminated; almost cloth-like,
dull brownish, sometimes shining a little on the middle of the
disk; pseudocardinals strong, ragged, two in the left valve

UNIO 685

and one in the right ; Jaterals very heavy, remote, double in the
left valve and having a tendency to be double in the right;
muscle scars small, deep, the anterior ones rough; beak cav-
ities shallow ; nacre flesh-color or purplish, rather dull.
Length 84, height 47, diam. 35 mm.
Southern Georgia; north Florida.
Type locality, Buck Lake, a bay of the Satilla River, Wayne

‘Co. Ga:

Unio downiei Lea, Pr. Ac. Nat. Sci. Phila., II, 1858, p. 166;
Hie Ae Nat Sein Phila: AV; 1859;.p. 2r0, pl: xxv, fig. Or;
Obs., VII, 1859, p. 28, pl. xxv, fig. 91—SowerrsBy, Conch.,
Icon., XVI, 1868, pl. Lxvint, fig. 350.—Simpson, Pr. U. 5S.
Mats, Miss CV) 18092. p. 43; spl. av) figs. 1-3; LVL, figs 5);
Sym, 1900; p17 33:

Margaron (Unio) dowmet Lea, Syn., 1870, p. 41.

A very solid, obovate, inflated, dull brown shell with strong
teeth and deep scars. Its obovate form will distinguish it
from the other members of the group.

UnIo GEMINUS Lea.

Shell slightly rhomboid or almost evenly long elliptical, in-
flated, rather solid, inequilateral ; beaks moderately full but not
high ; posterior ridge elevated, subangular or narrowly round-
ed, inclined to be double below, ending behind at and below
the median line in a slight biangulation ; surface with delicate,
concentric ridges; epidermis dirty, tawny-greenish to nearly
black with a few radiating rows of fine wrinkles, subshining
on the disk; left valve with two moderate, stumpy, ragged
pseudocardinals and two strong, curved laterals; right valve
with one pseudocardinal and a vestigial one above it, with
one solid lateral: beak cavities not deep; anterior muscle scars
impressed ; posterior scars elliptical, shallow ; nacre lurid pur-
plish, iridescent behind.

Length 76, height 44, diam. 29 mm.

Georgia.

Type locality, Buckhead Creek, Burke Co., Ga.

686 UNIO

Unio geminus Lea, Pr. Ac. Nat. Sci. Phila. VIII, 1856, p.
202; Jl.“Nat. Sc. Phila 1858)sp:037 ple xehe. 45 1Obss
VI, 1858, p. 63, pl. x, fig. 45—SIMPsoN, Syn., 1900, p. 733.

Margaron (Umo) geminus Liza, Syn., 1870, p. 41.

Unio satillaensis Lwa, Pr. Ac. Nat. Sci. Phila., II, 1858, p. 166;
Ji. Ac. Nat. Scr. Phila." 1V;-1850" p= 216;- pl xxvin, tie, 90r
Obs., VII, 1850, p. 34, pl. xxvui, fig. 96.

Margaron (Umo) satillaensis LeA, Syn., 1870, p. 41.

This differs from U. downiei in being less solid, in its nearly
elliptical instead of obovate form, and in being a smoother
shell. To the naked eye it appears as if delicately, radially
sculptured on the disk, and under a glass it is seen that there
are radiating rows of fine longitudinal folds of the epidermis.
I cannot possibly separate U. satillaensis, its only difference
consisting in a darker epidermis and slightly greater propor-
tionate height.

UNIO LECONTIANUS Lea.

Shell subelliptical or subrhomboid, inflated generally solid,
inequilateral; beaks full and apparently somewhat elevated;
posterior ridge high, somewhat double below, ending near the
base in a scarcely produced biangulation; base line curved or
nearly straight; anterior end rounded; dorsal line curved;
surface with uneven growth lines; epidermis smooth, tawny
and raved in young shells, brownish and rayless in old ones,
dull or subshining, showing occasional radial rows of longi-
tudinal wrinkles; pseudocardinals strong, low, very rough,
two in the left valve and one with sometimes a vestigial one
above it in the right: left valve with two strong, curved lat-
erals; right valve with one, which is inclined to be double;
beak cavities not deep; muscle scars impressed, rather large;
nacre dull purplish.

Length of type, a young shell, 70, height 45, diam. 28 mm.

Length 83, height 50, diam. 38 mm.

Georgia.

Type locality, Conoochee River, Ga.

UNIO 687

Margarita (Unio) lecontianus Laas, Syn., 1836, p. 23; 1838, p.
18. ;

Unio lecontianus Lea, Tr. Am. Phil. Soc., VI. 1838, p. 40, pl.
xt 35; Obs., IL, 1838p. 40, pl. x11; fig. 35.— Han ey,
Div., siells, 1643, p.. 188, pl. xxi, figs. 11, 51—CueEnu;, Il.
Conch., 1858, pl. xxiv, figs. 6, 6a, 6b—Sowersy, Conch.
Icon., XVI, 1866, pl. Xxxxi1, fig. 173.—Simpson, Syn., 1900
P. 733-

Margaron (Unio) lecontianus Lea, Syn., 1852, p. 26; 1870, p.
Al.

More solid, higher in proportion, and having lower, rather
heavier pseudocardinals and deeper muscle scars than U. gem-
mus. It seems to stand as a connecting link between that
species and U/. spissus, in fact all of the species of this group
are exceedingly close and variable and, although I have not
seen any great amount of material belonging to it, I have

,

found a number of specimens | could not satisfactorily place.
I formerly thought that U. contrarius Conrad, was a small
specimen of this with contrary teeth. Since reaching that
conclusion I have seen material which inclines me to think
I may have been wrong and I place that species in the genus
Lampsilis with hesitation.

Unio spissus Lea.

Shell subrhomboid or subobovate, being somewhat narrowed
in front, solid, moderately to greatly inflated, somewhat in-
equilateral; beaks full and high; posterior ridge high, angled,
showing a tendency to become double below, ending at or a
_ little above the base in a blunt point or biangulation; base
line more or less curved; dorsal line curved; anterior end
somewhat narrowed and rounded; epidermis brownish-green
in young shells and sometimes faintly rayed, reddish-brown
and rayless in old shells: somewhat concentrically sulcated,
rather dull; pseudocardinals small, compressed, not very per-
fect in adult shells, often strongly cross-striated, double in each
valve, the upper one in the right valve small; left valve with

688 UNIO

two heavy, curved, granular laterals; right valve with one,

which is sometimes almost double ; beak cavities often impress-

ed; muscle scars rather deep; nacre lurid purple.

Length of type, a young shell, 78, height 50, diam. 38 mm.

Length 103, height 65, diam. 47 mm.

Georgia.

Type locality, Satilla River, Wayne Co., Ga.

Unto spissus Vea, Pr. Ac. Nat. Sei. Phila lll, 150, p, 112
jlu Ae. Nat) Scr. Phila, AV, 21850; p- 208) ipl xxv hese.
Obs., VII, 1859, p. 26, pl. xxv, fig. 89.—Sowerrsy, Conch.
Icon., XVI, 1868, pl. LXxxvin, fig. 476.—Simpson, Syn.,
(900, p:"734-

Margaron (Umio) spissus Lea, Syn., 1870, p. 41.

The epidermis of this species, if it is a species, is darker than
in any of the allied forms. The shell is very solid, the pseudo-
cardinals quite small and for a shell of its solidity remarkably
compressed; in old specimens they are solidly cross-striate.
The posterior ridge is higher and more angulated than in any
of the others. Yet I have seen shells that I cannot say with
certainity whether they are this or U/. downiet.

| Group otf Unio fisherianus.

Shell elongated, rather thin, subcompressed, pointed behind
and sometimes slightly biangulate; posterior ridge generally
well developed; beaks low, the sculpture consisting of a few
coarse, slightly irregular ridges, which run nearly parallel with
the growth lines, generally heavier where they cross the pos-
terior ridge; epidermis sometimes rayed, shining ; pseudocard-
inals usually compressed; laterals long, straight and lamellar ;
beak cavities very shallow and containing two or three dorsal
sears at some distance behind the beaks; muscle scars well
marked, the posterior ones elongated; nacre generally dull.
Animal with the gills greatly elongated, inner the larger,
more or less free from the abdominal sac; marsupium occupy-
ing nearly or quite the whole length of the outer branchie ;
palpi elongated; mantle thin, thicker on the edge.

UNIO 689

UNIO LANCEOLATUS Lea.

Shell elongated, subelliptical or subobovate, subcompressed
or convex, inequilateral, subsolid; beaks not full or elevated,
their sculpture not seen; posterior ridge full, narrowly round-
ed, ending in a somewhat drawn-out point about on the median
line; sometimes the point is turned up a little; surface with
light incremental lines; epidermis straw-color, yellow or yel-
lowish-green or brown, often showing the dark rest marks,
shining ; pseudocardinals subcompressed, double in each valve,
the upper one of the right valve small, laterals straight, one in
the right valve and two in the left ; muscle scars small, shallow ;
nacre bluish-white, flesh-color or salmon-tinted, thick in front.

Length 58, height 25, diam. 15 mm.

Length 62, height 25, diam. 13 mm.

North Carolina; Virginia.

Type locality, Tar River, Tarboro, N. C.

Unio lanceolatus Lex, Tr. Am. Phil. Soc., 1828, p. 266, pl. 111,
fig. 2: Obs., I. 1834, p. 8, pl. 10, fig. 2—Conrap, Monog.,
III, 1836, p. 32, pl. xtv, fig. 2—HAaANLey, Biv. Shells, 1843,
p. 204, pl. xx, fig. 60; xx, fig. 26—CueEnu, Ill. Conch.,
1858, pl. vi, fig. 1, ta, 1b-—KustEeR, Conch. Cab. Unio,
1861, p. 204, pl. Lxvut, fig. 4.—Sowerry, Conch. Icon., XVI,
1866, pl. xi, fig. 236.—StMpson,. Syn., 1900, p. 734.

Margarita (Unio) lanceolatus Lea, Syn., 1836, p. 35
p. 24.

Margaron (Unio) lanceolatus Lea, Syn., 1852, p.
Pp. 57:

Unio lanceolata Desuayes, Enc. Meth., IT, 1830, p. 585.
A delicate, light-colored, polished species, which bears about

the same relation to U. fisherianus and other members of the

group that Lampsilis anodontoides and fallaciosa do to L.

recta. Indeed it often closely imitates a voung delicate falla-

ciosa, but is more elongated and compressed.

UNIo viriputus Lea.

Shell elongated, subelliptical, a very little wider behind than
in front; inequilateral, scarcely subsolid, convex; beaks rather
low, not inflated, their sculpture apparently strong, longitu-

690 UNIO

dinal ridges; posterior ridge full, subangular, inclined to be
double below, ending in a slight biangulation behind at and
below the median line; base a little produced behind the mid-
dle; surface finely, concentrically sulcate; epidermis bright
yellowish-green, with one or two faint rays on the dorsal
slope, polished ; pseudocardinals subcompressed, double in the
left valve and single in the right; laterals long and delicate;
muscle scars shallow: nacre bluish.

Length 35, height 14, diam. 8 mm.

Type locality, Neuse River, near Raleigh, North Carolina.
Unio viridulus Les, Pr. Aco N: Sci. Phila, VIL; 1863, ps 103;

jJiAcNat.-Sct. Phila. Vi, 1866, p.-1o;spls im, sescr7 Oese

XI, 1867, p. 14, pl. 1, fig. 17—SIMPson, Syn., 1900, p. 734.
Margaron (Unio) viridulus Lea, Syn., 1870, p. 58.

Evidently a young shell and it may be the young of some
other elongated species, which has a dark epidermis when
adult. I do not think it is a young lanceolatus, as it is fuller
on the posterior half of the base line than that species and has
a somewhat double, broader posterior ending. Besides, it is
more decidedly concentrically suleate than anything I know
of that species.

Unto propuc’ttus Conrad.

Shell elongated, subcompressed or compressed, subsolid, in-
equilateral, the dorsal and ventral lines nearly straight and
parallel, the anterior end rounded, but often cut away a little
below ; posterior end drawn out to a point at or a little below
the median line; posterior ridge rather low ; beaks not elevated
or full, their sculpture not seen: surface having fine, uneven,
incremental sculpture; epidermis dark reddish-brown or green-
ish-brown, subshining; pseudocardinals small, stumpy, two in
the left valve and one in the right; left valve with two remote
laterals ; right valve with one, which is often somewhat double ;
anterior scars impressed; posterior scars shallow; nacre pur-
plish, often salmon-tinted.

Length 67, height 26, diam. 15 mm.

Length 68, height 24, diam. 14 mm.

UNIO 691

Type locality, Savannah River at Augusta, Ga. Also, Poto-
mac River, Va.; Emmitsburg, North Carolina, etc.

Unio productus Conrap, Monog., III, 1836, p. 31, pl. x1v, fig.
1.—HAn ey, Biv. Shells, 1843, p. 205, pl. xxi, fig. 17.—
KuSsTER, Conch. Cab. Unio, 1852, p. 66, pl. xvi, fig. 2.—
SIMPSON, Syn., 1900, p. 735.

Margarita (Unio) productus Lea, Syn., 1836, p. 37; 1838, p.
24.

Margaron (Unio) productus Lea, Syn., 1852, p. 37; 1870, p.
60.

Elliptio productus ORTMANN, Ann Car. Mus., VIII, 1912,
270.

Unio barrotti Kuster, Conch. Cab. Unio, 1861, p. 189, pl. LIx,
fig. 6.

None of the specimens I have seen exactly agree with Con-
rad’s figure and description in the Monography, being a little

less solid and inflated, with dorsal and ventral lines not quite
so nearly parallel. Dr. Lea has specimens from Emmitsburg,
North Carolina, which he labels U. productus, that agree well
with our more northern specimens.

Unio NASuTULUS Lea.

Shell elongated, subrhomboid, subelliptical or slightly obo-
vate, rather conipressed, scarcely subsolid, inequilateral ; beaks
apparently low and not inflated; posterior ridge subangular,
ending behind in a drawn-out point just below the median line ;
surface closely, concentrically striate; epidermis greenish-
brown, faintly rayed, dull or subshining; base line curved, full
behind the middle; pseudocardinals stumpy; two in the left
valve and one in the right; laterals delicate, straight ; muscle
scars small, the posterior ones faint; nacre dirty pale brownish
or purplish, iridescent behind.

Length 45, height to, diam. 10 mm.

Type locality, Livingston’s Creek, Brunswick County, ‘North
Carolina.

Unio nasutilus Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 192

692 UNIO

Unio nasutulus Lea, Jl. Ac. N. Sct. Phila., VI, 1866, p. 12, pl
w1, fig. 9; Obs., XI, 1867, p. 16, pl. 11, fig. 9—SIMPson,
SYN. 1900, p75:

Margaron (Unio) nasutiulus Lea, Syn., 1870, p. 60.

The name was originally spelled nasutilus, a typographical
error, no doubt, and was afterwards changed by Dr. Lea to
nasutulus. His specimens are small, rather shorter in propor-
tion than prodiuctus or fisherianus, and in some cases inclined
to be obovate.

UNIO FISHERIANUS Lea.

Shell elongate, compressed or subcompressed, rather thin to
subsolid, inequilateral, with low beaks, whose sculpture con-
sists of strong, longitudinal, corrugated ridges; posterior ridge
well developed, subangular, generally curved down in the mid-
dle, ending behind in a long drawn-out point about at the
median line, the point often turned up a little; anterior end
rounded, wider than the hinder end; surface with decided
concentric striz; epidermis olive, dirty green, brownish or
nearly black, often feebly rayed, scarcely shining; pseudocar-
dinals stumpy, two in the left valve and one, sometimes two,
in the right: laterals straight; anterior scars impressed ; pos-
terior scars shallow; nacre whitish or purple-tinted, iridescent
behind.

Length 75, height 26, diam. 14 mm.

Length 76, height 30, diam. 18 mm.

Length 92, height 35, diam. 18 mm.

Virginia; Maryland; Pennsylvania, in the Atlantic drainage.

Type locality, Headwaters of Chester River, Md.

Unio fisherianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 8, pl. rv,
fig. 8; Obs., IT, 1838, p. 8, pl. rv, fig. 8—HAnLEy, Biv. Shells,
1843, p. 206, pl. xxu, fig. 52—CHENU, II]. Conch., 1858, pl.
XxX, figs. 4, 4a, 4b—KusTeEr, Conch. Cab. Unio., 1861, p.
205, pl. Lxvimi, fig. 6—RereEve, Conch. Icon., XVI, 1865, pl.
XXIV, fig. 113.—HaArtmMan and MicHeEener, Conch. Cest.,
1874, p. 90, fig. 187.—Simrson, Syn.,-1900, p. 735.

Margarita (Unio) fisherianus Les, Syn., 1836, p. 37; 1838, p.
24.

UNIO 693

Margaron (Umi) fisherianus Lea, Syn., 1852, p. 37; 1870, p.
Go:

Unio nasutus CONRAD (part), Monog., IT, 1838, pl. xvii, fig. 1.
It is difficult to separate this at all times from the northern

form of what I believe is U. preductus. It is generally nar-

rower and more drawn out behind, and the posterior ridge

is almost invariably curved down in the middle, which is

scarcely ever the case with productus.

UnIo EMMONSII Lea.

Shell rather large, elongated, irregularly ovate, convex, sub-
solid, inequilateral; beaks slightly elevated, compressed, their
sculpture consisting of strong, corrugated ridges that nearly
follow the growth lines; posterior ridge strong, angled, curved
down in the middle, ending behind about at the median line in
a sharp, up-curved point; base line almost straight, curved up-
ward towards the posterior end; surface with uneven growth
lines, somewhat sulcate; epidermis tawny or yellowish-green
and rayed in young shells, becoming brown in old specimens ;
left valve with two strong, rough pseudocardinals and two lat-
erals; right valve with two pseudocardinals, the upper small,
and one lateral; muscle scars impressed; nacre dirty, pale
brownish or purplish, iridescent behind.

Length 111, height 45, diam. 25 mm.

North Carolina.

Type locality, Roanoke River, Weldon, N. C.

Unio emmonsit Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 86,

Pee Ne ocr Philas. WV, 19025.p.50, pt 11, fig. 203; Obs.,

VIII, 1862, p. 60, pl. 11, fig. 203.—Sr1mpson, Syn., 1900, p-

£35:
Maregaron (Unio) emmonsti Las, Syn., 1870, p. 60.

This is a large edition of Unio fisherianus. Its dimensions
are greater in every way, it is considerably solider, and some-
what more inflated; the posterior ridge is higher and sharper.

UNIO SUBINFLATUS Conrad.

Shell subrhomboid, higher behind than in front, subsolid,
subcompressed, inequilateral; beaks apparently very low and
compressed ; anterior end rounded; dorsal line straight, meet-

694 UNIO

ing the truncation of the dorsal slope at an angle, posterior
ridge full, somewhat double below, ending behind in a biangu-
lation at and below the median line; base full behind the mid-
dle; epidermis reddish-brown and olivaceous, smooth with un-
equal green rays; pseudocardinals small; laterals slightly
curved; muscle scars distinct ; nacre pale purple.

Length 74, height 37, diam. 19 mm.

South Georgia; Florida.

Type locality, Savannah River, Augusta, Ga.

Unio subinflatus Conrap, Monog., XI, 1838, p. 97, pl. Liv, fig.

1.—SIMPSON, Syn., 1900, p. 736.

Margaron (Unio) subinflatus Lea, Syn., 1870, p. 52.

Shorter and apparently more solid than U. aheneus. The
posterior truncation in this species is square while in aheneus
it is oblique, the longer point being below. I have never seen
specimens that I can positively refer to this species.

UNIO AHENEUS Lea.

Shell long rhomboid, usually a little higher behind, sub-
solid, subcompressed, inequilateral; beaks low, compressed,
their sculpture ridges that run parallel with the growth lines;
posterior ridge fuli, inclined to be angled and double, ending
behind in a biangutation near the base, the lower angle longer ;
base line nearly straight, sometimes full behind the middle;
surface unevenly, concentrically striate; epidermis yellowish-
green and rayed in young shells, dark brown on old specimens.
scarcely shining; pseudocardinals small, often strongly cross-
striate and imperfect; laterals delicate; muscle scars shallow;
nacre purplish or chocolate.

Florida.

Type locality, Black Creek, Fla.

Unio ahencus Lea, Desc. t2 Uniones, 1843 (no paging) ; Tr.
Am: Phil. Soc., IX, 1846, p. 280) pl cagy fe 29 Ons. IY,
1848, p. 38, pl. xu, fig. 9—Sowersy, Conch. Icon., XVI,
1866, pl. xxxvi, fig. 194.—Srmpson, Pr. U. S. Nat. Mus.,
XV, 1892; p. 431, pl. uxxn, fig. 6; Syn., 1900, p. 736.

UNIO 695

Margaron (Unio) aheneus LEA, Syn., 1852, p. 37; 1870, p. 60.
The type is a young shell, but I have seen a quantity of shells
from Lake Ashby, Florida, whose young agree well with it.

Unio watont B. H. Wright.

Shell much elongated, compressed, inequilateral, rather thin,
subrhomboid ; anterior end angled above, somewhat cut away
below ; base line nearly straight, full just behind the middle ;
dorsal line straight or slightly curved, being prodticed into a
low wing; dorsal slope obliquely truncated; posterior ridge
angled, inclined to be slightly double below; ending behind
near the base of the shell in a feeble biangulation, the lower
angle longer; surface concentrically striate; epidermis dark
brown, showing vestiges of rays, dull or scarcely shining;
pseudocardinals low, small, not perfectly developed, double in
both valves; laterals long, straight and delicate; muscle scars
shallow ; nacre chocolate.

Length 80, height 30, diam. 15 mm.

Length 74, height 30, diam. 16 mm.

Florida.

Type locality, Lake Woodruff, Valusia Co., Fla.

Umo waltom Bs H. Wricut, Pr. Ac. N. Sci. Phila., 1888, p.

114, pl. 1, fig. 3— Simpson, Pr. U. S. Nat. Mus., XV, 1892,

Po 434, pl. Lex, fo: 7; Syn, 1900, p. 730.

I have only seen a few specimens of this shell but I have
always suspected that it was only an elongated, rather delicate
variety of U. aheneus. ‘The shorter shell, whose measurements
are given above, seems to hint at a connection, yet from what
material I have seen I do not feel justified in uniting the two.
U, waltoni is more sharply and obliquely pointed behind than
aheneus. ‘The beaks of all the shells I have seen are so badly
eroded that I can make nothing out of them.

UNIO ROSTRAFORMIS Lea.

Shell elongated, subelliptical or subovate, compressed or
subcompressed, rather thin, inequilateral; beaks scarcely ele-
vated, compressed, their sculpture consisting of slightly broken
ridges that run nearly parallel with the growth lines ; posterior

696 UNIO

ridge moderate, narrowly rounded or subangulate, sometimes
inclined to be double below, ending behind in a long point at
or below the median line; anterior end rounded or cut away
a little below ; base line nearly straight or lightly curved; dor-
sal slope obliquely subtruncated; surface with fine, concentric
sculpture ; epidermis dirty yellowish-green, profusely but feebly
raved, rather rough and dull; pseudocardinals low, sometimes
imperfect, double in each valve; laterals straight ; muscle scars
shallow ; nacre whitish, tinged with dirty purple.

Length 83, height 30, diam. 16 mm.

Georgia.

Type locality, Swift Creek, Macon, Ga.

Unio rostreformys na, Pr. “Ac. N. Se Phila; VE, 1856, p.
262.—SIMpson, Syn., 1900, p. 736.

Unio rostriformis Lea, Jl. Ac. N. Sci. Phila., 1V, 1858, p. 64,
pl. x, fie. -46°-Obs., Vi. 1858, p64, plas, fie. 46:

Margaron (Unio) rostriformis LEA, Syn., 1870, p. 60.

Unio maconensis Lea, Pr. Ac. N. Sci. Phila., 1X, 1857, p. 172;
Ji AG IN: Seite Rhilas VW. S1Sis8. ip. 1034 pls sexe wher a7 Osa.
Vi,1858, p2.03) pl Xx, fig73.

Margaron (Unio) maconensis Lea, Syn., 1870, p. 60.

Close to fisherianus but rougher and having a greener epi-
dermis. ‘The posterior ridge of this species is generally
straight, and sometimes curved up a little in the middle; that
of fisherianus generally is curved down in the middle. U. ros-
treformis is usually a little higher behind than fsherianus.

UNIO DUTTONIANUS Lea.

Shell long, subelliptical, the dorsal and ventral lines being
nearly parallel, inequilateral, subinflated, solid; beaks appar-
ently not much elevated; posterior ridge moderate, narrowly
rounded, becoming almost double below, ending in a feeble
biangulation on or a little above the median line; anterior end
rounded; base line almost straight; epidermis dark brown,
obscurely rayed; pseudocardinals very small, compressed ; lat-

UNIO 697

erals long, apparently curved down in the middle; anterior

. muscle scars impressed; posterior scars indistinct ; nacre white

and iridescent.

Length 70, height 25, diam. 17 mm.
Type locality, Ogeechee Canal, Savannah, Georgia.

Unio duttomanus Ira, Pr. Ac. N. Sci. Phila., II, 1841, p: 31;
ise oN oc. Phila. VE, 1842. p. 236, pl. xxi, fig. so;
Obs., III, 1842, p. 74, pl. xxu, fig. 50.—CHENU, Ill. Conch.,
1858, pl. xxxut, figs. 4, 4a, 42—Sowerry, Conch. Icon.,
XVI, 1868, pl. xci, fig. 492.—Simpson, Syn., 1900, p. 736.

Margaron (Unio) duttenianus Lia, Syn., 1852, p. 35; 1870,
P. 57:

There seems to be only one specimen of this species known,
and it is not in the Lea Collection. It is apparently close to
folliculatus, but is more cylindrical and has white, shining

nacre. As figured by Dr. Lea, the laterals are curved down in
the middle.

UNIO FOLLICULATUS Lea.

Shell much elongated, straight or slightly arcuate, the dorsal
and ventral lines being nearly parallel, convex or subinflated,
subsolid, or rather thin, inequilateral, rounded in front, drawn
out to a point or slight biangulation at or just below the me-
dian line behind; the region of the base behind the center a
little produced ; posterior ridge well developed, inclined to be
somewhat double below, angled; surface with well marked, un-
even, rather fine, concentric sculpture; epidermis tawny-green
and faintly rayed in young shells, becoming dark brown or
black in old ones, scarcely shining; pseudocardinals subcom-
pressed, double in each valve, the upper one in the right valve
small: laterals straight; muscle scars distinct; nacre whitish,
tinged with dirty purple.

Length 92, height 32, diam. 19 mm.

Length 80, height 29, diam. 16 mm.

Georgia.

Type locality, Savannah River, Ga.

698 UNIO

Unio folliculatus Lea, Tr. Am. Phil. Soc., VI, 1858, p. 38, pl.
x1, fig. 33; Obs., I, 1838, p. 38, pl. x1, fig. 33—HANLEy,
siv. Shells, 1843, p. 204, pl. xxi, fig. 55.—CHENu, II.
Conch., 1858, pl. xxii, figs. 4, 4a, 4b—lKustrr, Conch. Cab.
Unio, 1861, p. 202, pl. Lxvu, fig. 4—Sowrrby, Conch. Icon.,

XVI, 1868, pl. xc, fig. 493.—SIMPSON, Syn., 1900, p. 737.
Margarita (Unio) folliculatus Lka, Syn., 1836, p. 34; 1838,

p23:

Margaron (Unto) folliculatus Lea, Syn., 1852, p. 35; 1870, p.
Side

Umo attenuatus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 157;
JioAc. Ne Ser. Phila; VI, 1874-p.414 pl xive es 26 One.
XIII, 1874, p. 45, pl. xiv, fig. 38.—Simpson, Syn., 1900, p.
730.

Umo. exacutus Lea, Pr.cAc N. Scr Phila. i 1872p. 1G.
Ji Ac. No Set. Phila, VBL 1874 plas, pl xy hie 23) Obss
MUL 1874.9. 40; pl ave. Aa

Unio rostellum Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 160;
Jl: Ac. Ser Philay Villian 745 44 plex ie 4 Ops
XI, 1874, p. 48, pl. xv hig: An.

After bestowing additional study on the puzzling forms of
this group, I confess that I can see no valid reason why Unio
attenuatus should be kept separate from U. folliculatus. ‘The
type of U. rostellum is quite a thin shell, that of U. attenwatus
is a little more solid, while U. folliculatus and exacutus are
more solid. But there seems to be every variety in the way of
intermediates and the general form of all is the same.

UNIO SHEPARDIANUS J[ea.

Shell excessively elongated, usually more or less arcuate,
rarely straight, generally but not always, higher in front, sub-
solid, subcompressed to subinflated, very inequilateral; beaks
compressed and but little elevated above the dorsal line, their
sculpture apparently strong, slightly doubly-looped ridges;
posterior ridge well developed, subangular or narrowly round-
ed, sometimes double below, ending behind in a point or bian-
gulation near the base of the shell; surface irregularly, concen-
trically sculptured; epidermis greenish and often feebly rayed

UNIO 699

when young, dark brown or black and rough in old shells;
pseudocardinals rough, scarcely compressed, double in both
valves; laterals long and straight, inclined to be club-shaped,
granulated ; anterior muscle scars impressed, separate; poste-
rior scars well-marked, elongated; nacre coppery, chocolate,
dull purple or white, dull to brilliant.

Length 190, height 44, diam. 25 mm.

Altamaha River, Georgia.

Type locality, Hopeton, near Darien, Ga.

Unio shepardianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 95, pl.
xu, fig. 38; Obs., I, 1834, p. 207, pl. x11, fig. 38.—Conrap,
Monog., VIII, 1837, p. 70, pl. xxx1x.—HAn _ey, Biv. Shells,
1843, p. 203, pl. xx1u, fig. 25.—KustTeER, Conch. Cab. Unio,
1852, p. 65, pl. xvi, fig. 1—?CHENU, Man., 1859, II, p. 139,
fig. 647.—RereEvE, Conch. Icon., XVI, 1865, pl. xrx, fig. go.—
SIMPSON, Syn., 1900, p. 737.

Vargarita (Unio) shepardianus Lea, Syn., 1836, p. 34; 1838,
p. 23.

Margaron (Unio) shepardianus Lea, Syn., 1852, p. 35; 1870,
P. 57:

Unio sheppardianus CatLow and Reeve, Conch. Nom., 1845,
p. 64.

This species is unique and need never be mistaken for any
thing else. The specimen measured is one of the largest I
have seen; it is somewhat rayed behind and has a white nacre.
The shells in a superficial way sometimes resemble some of
the Chinese forms, but they are generally more arcuate; they
are wider behind than in front and attain a much greater size.

Group of Unio popeii.

Shell elongated, narrowed in front, and biangulate behind,
with the base slightly sinuate, feebly sulcate; beaks not prom-
inent, sculptured with rather fine, somewhat broken, often faint
ridges, which have a tendency to fall into two rounded loops ;
pseudocardinals compressed, high, sharp, ragged ; laterals Jong,
slightly curved; cavity of the beaks shallow; cicatrices not
deep. The shell is only a little thickened in front, and that of
the female is slightly swollen at the posterior base.

7CO UNIO

Animal with the marsupium occupying the whole length of
the outer gills; ovisacs not separated by a sulcus; gills long,
inner a little the larger throughout, generally free their whole
length from the abdominal sac; palpi enormous, wide, oval,
slightly pointed behind, united two-thirds of their length te
the mantle; mantle double on its edge; branchial openin;
large.

Unio porett Lea.

Shell elongated subtrapezoidal, inequilateral, scarcely sub-
solid, rather compressed, narrowed in front and the middle
and wider behind, with a low, double posterior ridge, which
ends in a wide, rather faint posterior biangulation; posterior
slope obliquely subtruncate above; base line generally incurved
at the middle, sometimes nearly straight, usually a little full
behind the middle; beaks rather low but sharp, their sculpture
consisting of a few doubly-looped ridges, the hinder loop
heavier ; epidermis olive-green, sometimes clouded with tawny,
often smoky, slightly rayed on the earlier growth, somewhat
imbricated behind; left valve with two small pseudocardinals
and two long, curved or nearly straight laterals; right valve
with one pseudocardinal, sometimes with a faint second one
above; beak cavities shallow, showing the dorsal pits; muscle
scars shallow ; nacre dull purplish or purplish lead-color. The
female shell seems to be a little fuller at the post-base than
that of the male.

Length 80, height 35, diam. 22 mm.

Length 57, height 30, diam. 16 mim.

South Texas; northeast Mexico.

Type locality, Devil’s River, Texas; Rio Salado, New Leon,
Mexico.

Unio pope Lua, Pr. Ac. N. Sci. Phila., IX, 1857, p. 102; Jl.
Ac, N. Sci. Phila., IV,. 1858, p. 372, pl. uxv1, fig. 197; Obs.
VIII, 1860, p. 54, pl. Lxvi, fig. 197——SIMPSON, Syn., 1900,
p. 738.

Unio popei Sowrrsy, Conch. Icon., XVI, 1868, pl. LXxxt, fig.
430.

Margaron (Unio) popeii Lea, Syn., 1870, p. 57-

UNIO 701

Lampsilis poper Pirspry, Pr. Ac. Nat. Sci. Phila., 1909, p. 535.
Elliptio popet ORTMANN, Ann. Car. Mus., VIII, 1912, p. 271.
? Unio vere-pacis Tristam, P. Z. S. Lond. 1863, Pt. 3, p. 414.

—Simpeson, Syn., 1900, p. 738.

Unio ravistellus var. vere-pacis VON Marvrerns, Biol. Cent.

ineT.,. WOU TOO1,: py i520; pl: ReRVIIT, figs; 1, 14.

The greatest diameter of this shell is at or a little behind the
center; from this point there is a gradual and nearly straight
slope to near the anterior end, from which place it rapidly
narrows to the anterior point. I have examined gravid fe-
males of this species and the marsupium occupies the entire
outer gills. ‘This form differs from U. poeyanus in being
wider behind and darker colored. Its beaks are much more
strongly sculptured.

Unio vere-pacis Tristam is probably a synonym.

UNIO POKYANUS Lea.

Shell elongated, inequilateral, scarcely, if at all, narrower
in front, convex, subsolid, with a low, rather rounded poste-
rior ridge, which is hardly biangulate; beaks rather low but
sharp, their sculpture consisting of very faint ridges; dorsal
line nearly straight; basal line straight or slightly incurved at
the middle, parallel with the dorsal line; anterior end rounded ;
posterior end rounded below, obliquely subtruncate above ;
epidermis straw-colored in young shells, becoming faint brown-
ish-green, often banded with yellowish, in older shells, some-
times feebly rayed and suicate; left valve with two subcom-
pressed pseudocardinals, the hinder reflexed, and two feeble
laterals; right valve with one pseudocardinal and one lateral ;
beak cavities and muscle sears shallow ; nacre whitish.

Length 55, height 23, diam. 15 mm.

Rio de las Balsas, near Coyucan, Mexico.

Unio poeyanus Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 85;
Ome. = V1, 1857. p- 35, pl. xxx, fio. 30.5 Jl. Ac. N. Sci. Phila,
III, 1858, p. 315, pl. Xxx, fig. 30.—Sowersy, Conch. Icon.,
XVI, 1868, pl. xc, fig. 486.—Srmpson, Syn., 1900, p. 738.

_

Margaron (Unio) poeyanus Lea, Syn., 1870, p. 57.

702 UNIO

This differs from U. popeii in several important particulars
It is more nearly cylindrical, its greatest diameter being he-
hind the middle. but it scarcely diminishes in front of that;
its nacre is lighter colored and the beaks are much smoother.

Section CANTHYRIA Swainson, 1840.

Canthynia Swainson, Treat. Mal., 1840, p. 378.

Shell inflated, suboval, spinose, with a high, rather sharp
posterior ridge, above which it is somewhat truncated, the
posterior slope being sometimes slightly wrinkled ; beaks rather
compressed, the sculpture not seen; epidermis smooth and
shining, variegated with angular blotches; hinge sharply
curved at the center; pseudocardinals rather compressed ; lat-
erals short, remote, the hinge plate narrowed; beak cavities
rather deep. Animal with the marsupium occupying the whole
of the outer gills, forming a smooth pad; branchiz very large,
round below, inner the larger, free nearly their whole length
from the abdominal sac ; palpi large ; mantle double on its edge,
sometimes with a few papille in front of the branchial open-
ing; branchial opening small; superanal opening colored 1n-
side.

Type, Unio spinosus Lea.

UNIo SPINOSUS Lea.

Shell subrhomboid or subtriangular, subinflated to inflated,
rather solid, inequilateral or almost equilateral; beaks high
and full, their sculpture apparently a few short, irregular cor-
rugations; posterior ridge well developed, decidedly angled,
ending behind in a point at or just below the median line;
anterior end rounded; dorsal line sharply curved at the beaks;
dorsal slope obliquely truncated; base line curved; surface
with very fine, concentric sculpture; epidermis tawny-yellow,
green or brownish, usually with faint and beautiful rays, shin-
ing; left valve with two rough, subcompressed peudocardinals
that are nearly opposite each other, with two short, club-
shaped, remote laterals; right valve with two opposed pseudo-
cardinals, the upper smaller, with one high lateral: hinge line

UNIO 703

-rounded and narrowed; muscle scars small, impressed; beak
cavities moderately deep; nacre fine rose-color, thicker in front.
The surface is ornamented with from one to five spines of
various lengths in each valve, varying from one to twenty-five
millimeters in length. They are either straight or crooked and
though usually arranged in a radial row just in front of the
posterior ridge they are sometimes scattered irregularly over
this part of the shell.

Length 102, height 60, diam. 33 mm.

Length 95, height 50, diam. 40 mm.

Type locality, Altamaha River. Georgia.

Unio spinosus 1£A, Desc. of New Sp. Unio, 1836, colored figs. ;
Pei, ell soc, VI, 1838, p: 57; plexviy fis. 50;‘Obs., IT,
£838, p. 57; pl. xvi, fig.°50.— JAY, Cat., 1839; p. 113, pl. v,
figs. I, 2.—Hantey, Biv. Shells, 1843, p. 182, pl. xx111, fig.
56.—Kustrr, Conch. Cab. Unio, 1856, p. 167, pl. xix, fig.
1.—CHENU, Ill. Conch., 1858, pl. xxur, figs. 6, 6a, 6b.—Sow-
ERBY, Conch. Icon., XVI, 1866, pl. xix, fig. 261—SIMPsoNn,
Syl LOGO). Pp: 730-

Margarita (Unio) spinosus Lia, Syn., 1836, p. 17, colored
plate; 1838, py 16:

Margaron (Unio) spinosus Lasa, Syn., 1852, p. 23; 1870, p. 35.

Canthyria spinosa Swanson, Tr. on Mal., 1840, pp. 276, 378.

Unio spinosa Goonricn, Ill. Nat. Hist., II, 1859, p. 523, fig.

Elliptio (?) spinosus ORTMANN, Ann. Car. Mus., VIII, 1912,
p. 260.

Probably this is the most remarkable member of the family
Unionide. Dr. Lea has a magnificent series of 31 specimens
ranging from young to old and exhibiting great variation. In
one specimen the right valve is destitute of spines; in another
there are no spines at all, but as it is somewhat eroded they
may have been eaten away. In a young shell a spine is seen
in each valve in the process of formation, being merely a short
tubular development open at the outer ends and in front. The
spines are compressed lengthwise, the growth lines on the
upper side of them running across them; on the lower side
it is curved sharply downward to a sort of median sulcus. No

704 UNIO

doubt the lobe of the mantle fills the hollow spines until it has
reached its full height, when it closes up the outer end and
in retreating fills the cavity solid or nearly so. One shell in
the Lea collection shows a spine broken off at the point where
it bifurcates and each part of the spine is hollow. The surface
of the shell is bright and usually rayed. One of Lea’s shells
has beautiful, dark, broad. blotched rays, which become nar-
rower below as if the dark color had been poured on at the
beaks and had run down the sides of the shell. It also has a
few detached blotches.

Notwithstanding the remarkable character of well-developed
spines on the only species of this group, U. spinosus, the animal
even when gravid does not present any striking peculiarities,
and is certainly a Unio.

Mr. Charles FE. Svkes, of Gardia, Georgia, in a letter written
to me, states that he found this species in the Altamaha River
about 15 miles above tide water in limited numbers, where they
usually burrow in white sand where there is running water
from two to four inches deep.

Section Unromerus Conrad, 1853.

Uniomerus Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 268.—

Ortmann, Ann. Car. Mus., VITI, 1912, p. 272.

Shell trapezoid, with a rounded posterior ridge, and pointed
or feebly biangulate behind; beaks not prominent, sculptured
with to to 15 curved, rather strong, concentric ridges, which
sweep decidedly upward behind, where they are drawn some-
what closely together ; epidermis generally rayless, often cloth-
like; pseudocardinals usually compressed; laterals delicate,
slightly curved; muscle scars large, shallow; nacre generally
lurid.

Animal with the marsupium occupying the whole length of
the outer branchiz, pad-like; gills large, inner the larger, free
nearly or quite the length of the abdominal sac; mantle gen-
erally rather thick, thicker and double on the edge.

Type, Unio tetralasmus Say.

Ortmann, (1. c.), raises this group to generic rank.

UNIO 705,

UNIO TETRALASMUS Say.

Shell elongated with dorsal and ventral lines nearly parallel,
convex to subinflated, rather thin to subsolid, inequilateral,
beaks somewhat full and elevated, their sculpture consisting
of six or seven moderate concentric ridges, which are evenly
and rapidly rounded up behind; posterior ridge widely round-
ed, ending behind in a point just below the median line ; on the
dorsal slope there are two radiating furrows, the slope being
slightly, obliquely truncate behind; anterior end evenly round-
ed; surface with feeble, concentric sulcations, and traces of
very fine radial sculpture ; epidermis yellowish-brown or ashy-
brown, banded with lighter color, rather smooth, often sub-
shining ; pseudocardinals two in each valve, the upper in the
right valve small, all subcompressed; laterals long, two in the
left valve and one in the right ; beak cavities impressed ; dorsal
scars immediately under the beaks; muscle scars smooth and
shallow ; nacre white.

Length of Say’s figure 112, height 49, diam. 35 mm.

Length 96, height 48, diam. 30 mm.

Alabama to ‘l’exas; north to Southern Missouri and Indian
Territory.

Type locality, Bayou St. John, New Orleans, La.

Unio tetralasmus Say, Am. Conch., III, 1830, pl. xx111.— Han-
LEY, Biv. Shells, 1843, p. 198, pl. xxi, fig. 49.—CHENU,
Bib. Conch., 1st. ser., III, 1845, p. 52, pl. x, figs. 1-3.—Simp-
SON, Syn., 1900, p. 739.—FRierson, Naut., XVII, 1893, p.
49, pl. 111, upper fig.

Margarita (Unio) tetralasmus Lea, Syn., 1836, p. 30; 1838, p.
21.

Margaron (Unio) tetralasmus Lea, Syn., 1852, p. 32; 1870, p.
50.

Uniomerus tetralasmus OrrMANN, Ann. Car. Mus., VIII,
112) p., 273.

Unio excultus Conrap, Monog., XI, 1838, p. 99, pl. Liv, fig. T.

Unio parallelus Conrap, Pr. Ac. N. Sci. Phila., I, 1841, p. 20.

Unio symmetricus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164;
pre nns Phil Sock 1853) p. 73) plea, fie, 17; Obs., IV,
To4Sy p. "47, “pl. WV, fig. 11.

706 UNIO

Margaron (Unio) symmetricus LEA, Syn., 1852, p. 32; 1870, p.

7.

Unio porrectus Conrab, Jl. Ac. N. Sci. Phila., 1854, p. 296, pl.
MMVI OIL 72 ;
Unio subcroceus CONRAD, Jl. Ac. N. Sci. Phila., VII, 1854, p.

2077) ple xvils fis: FLL
Unio jamesianus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 84; Jl.

Ac.cN. oct. Phila.,.JV;, 0858 4pe 53plevig tees uOhseavae

LOSS) Pat 52s uple Vi cease.

Margaren (Unio) jamesianus Les, Syn., 1870, p. 50.

A widely distributed, very abundant and variable species.
There are decided variations enough to make several perfectly
valid species in the material [ have examined, but they are so
completely blended together by connecting forms that 1t seems
to me better to make varieties of them. The specimen figured
by Say is much elongated, having the dorsal and ventral lines
nearly straight and parallel. It is, according to the colored
figure, yellowish-brown with an ashy tint and-has near the
base, two narrow, concentric, tawny bands. lLea’s type of
Unio jamesianus is a young and considerably distorted shell,
being injured and drawn in at the middle of the base, and dis-
eased along the hinge line, so that the hinge is curved upward.
He has several fine, healthy shells which he calls jamesianus
that agree with the type in texture, color and other characters,
excepting form, and these are exactly like Say’s figure of
tetralasmus. Generally it is smooth and shining, but I have
seen specimens that are slightly dull. In Indian Territory,
Southern Missouri and Texas specimens are abundant, which
are often a little darker than the type, varying into dark brown.
The dorsal and ventral lines of these specimens are sometimes
a little curved and in Texas it runs into the variety manubius.

Var. camptodon Say.

Shell subrhomboid, the base line usually incurved when
adult ; beaks sharper than in the type: surface dark, subshining
or rougish ; nacre bluish-white.

Length of Say’s figure 95, height 46, diam. 30 mm.

States bordering the Gulf of Mexico.

Type locality, New Orleans, La.

UNIO 7°7

Unio camptodon Say, Am, Conch., V, 1832, pl. xi1.—Han-
LEY, Biv. Shells, 1843, p. 198, pl. xxi, fig. 17—CHENU, Bib.
(Conch ist. ser, Cll, 1645, p: 53, pl. Xiv, figs. 2, 2a, 2b—
Sowersy, Conch. Icon., XVI, 1868, pl. Lxx, fig. 356.

Margarita (Umo) camptodon Lea, Syn., 1836, p. 30; 1838, p.
2K,

Margaran (Unio) camptodon LEA, Syn., 1852, p. 32; 1870, p.
50.

Unio tetralasmus var. camptodon SIMPSON, Syn., 1900, p. 740.

Unio geometricus Lea, Tr. Am. Phil. Soc., V, 1832, p. 38, pl.
Iveco, o> Obs... F-18345 perso; pli 1v,. fig. 10:

Unio decliwis geometricus FRtERSON, Naut., XVII, 1903, p. 49,
pl. 111, middle fig.

This form is decidedly obliquely truncated on the dorsal
slope; the posterior ridge is rather high and rounded and ends
at or near the base of the shell in a rounded point. Adult shells
have the base line incurved medially and the anterior end is
either evenly rounded or angled above. The surface is darker
and usually rougher than it is in typical specimens. It is a
little difficult to say just what Lea’s U. geometricus is, as the
type does not seem to be in his collection. It is a young shell
and is described as dark brown with a wrinkled and sometimes
obscurely rayed epidermis. It seems from the figure to stand
somewhat between Say’s camptodon and declivis, but I think
that the form is nearer the latter, as the base line is almost
straight.

Var. manubius Gould.

Shell often becoming large; dorsal and ventral lines more or
less curved, somewhat rhomboid, the dorsal slope being more
or less obliquely truncated; surface yellowish-ashy, dull or
feebly shining.

Length 102, height 55, diam. 33 mm.

Length 131, height 68, diam. 41 mm.

Type locality, Chihuahua, sixty miles from Fort Ringgold.
Unio manubtus Goutp, Pr. Bost. Soc. Nat. Hist., V, 1856, p.

220.

Margaron (Unio) manubius Lea, Syn., 1870, p. 54.
Unio manubrius Payrer, Conch. Sam., III, 1890, p. 158.

708 UNIO

Unio tetralasmus var. manubus SIMPSON, Syn., 1900, p. 740.

I am not aware that this form has ever been figured, but the
I,ea collection has a right valve from Chihuahua, Mexico,
which was donated by Dr. Gould under the name Unio man-
ubius. ‘The form, while slightly rhomboid by reason of the
oblique truncation of the posterior slope, becomes more nearly
elliptical than the type. The epidermis is sometimes more
nearly elliptical than the type. The epidermis is sometimes
dark and may either be dull or shining.

Var. dechivis Say.

Shell of moderate size. subrhomboid, somewhat rounded on
the base line; posterior ridge high, narrowly rounded and
standing out somewhat distinctly from the rest of the shell;
dorsa! slope having a wide, shallow, radial furrow just above”
and reaching to the posterior ridge, decidedly obliquely trun-
cated: surface dark brown, unevenly suleated and rough;
nacre sometimes purple-tinted.

Length of Say’s figure 74, height 39, diam. 25 mm.

Lower part of the Gulf States from Alabama to Louisiana.

Type locality, Bayou Teche, La.

Unio declivis Say, Transylvania Jl. IV, 1831, p. 527; Am.
Conch., III, 1832, pl. xxxv.—Han ey, Biv. Shells, 1843, p
200, pl. xxi, fig. 50—CueENnu, Bib. Conch., Ist. ser., IO ie
1645) p. AO, Ol) MINE, Mes cect. uae To Kuster, Conch. Cab:
Unio, 1852, p. 60, pl. xiv, fig. 1—-Frrerson, Naut., XVII,
1903, p. 49, pl. 1, lower fig.

Margarita (Unio) declivis Lea, Syn., 1836, p. 32; 1838, p. 22.

Margaron (Unio) declivis Lua, Syn., 1852, p. 33; 1870, p. 54-

Unio tetralasmus var. declivis StMpSON, Syn., 1900, p. 740.
Quite a distinct form, when typical, and apparently not very

abundant. The posterior ridge is elevated, its edges being

rather distinctly marked above and below ; it is rounded and
rather narrow and ends behind above the base in a sort of
beak, as noticed by Say. But I have seen specimens much

UNIO 79

like declivis with the base line almost straight and forms with
something of its shape but nearly smooth.

Frierson, (1. c.), considers declivis to be specifically distinct
from tetralasmus with geometricus Lea as a synonym.

Var. sayt Ward.

Shell rhomboid, with the dorsal and ventral lines very slight-
ly curved; dorsal slope decidedly obliquely truncated; beaks
rather full and high, their sculpture strong and distinct; pos-
terior ridge well developed, rounded and ending near the base
of the shell in a decided point; surface yellowish or greenish-
ash, generally with darker, concentric bands ; epidermis some-
times smooth, more commonly delicately, concentrically wrink-
led; nacre bluish-white.

Length 82, height 40, diam. 25 mm.

Ohio River system.

Type locality, Walnut Creek and Ohio Canal, Circleville, O.
Unio sayi Warp (in Tappan), Am. Jl. Sci, XXXV, 1839, p.

268, pl. 11, fig. 1.—Conrap, Monog., XI, 1838?, p. 102, pl.

iv, as. 2.—— Kuster, Conch... Cab. Unio, 1861, \ps.246, pl:

EK, Le. FT;

Unio savanus B. H. Wricut, Check List, 1888.
Unio electrinus Reeve, Conch. Icon., XVI, 1865, pl. xxv, fig.

121.

Unio tetralasmus var. sayi SIMPSON, Syn., 1900, p. 74T.

Sometimes becomes quite dark and elongated and I have
a series of intermediates before me, which shows a gradual
transition to typical U. tetralasmus.

The entire distribution of the species and all its varieties
is as follows:

Lower Mississippi drainage north to about latitude 40° ;
Ohio River system; Alabama River system and southwest
through Texas into northern Mexico. Not reported, so far
as I know, from the Tennessee and Cumberland rivers.

UNIO COLUMBENSIS Lea.

Shell rather elongated, rhomboid, inequilateral, somewhat
solid, convex or subinflated; beaks only moderately full and
elevated, their sculpture not observed; posterior ridge full,

710 UNIO

rounded, ending behind in a blunt point at or very near the

base of the shell: base line incurved a little in the middle ; dor-

sal line nearly parallel with the base line; anterior end rounded ;
posterior end obliquely subtruncated, the outline being some-
what curved, meeting the dorsal line with a sharper curve;
surface finely, concentrically striate; epidermis finely, concen-
trically wrinkled, becoming cloth-like around the border of the
shell, smoother on the disk, greenish-brown to reddish-brown ;
pseudocardinals stumpy, quite solid, rough, two in the left
valve and one in the right; laterals remote, somewhat club-
shaped: muscle scars shallow, anterior separate, posterior
large; nacre whitish, often tinted with lurid purple.

Length &8, height 44, diam. 28 mm.

Length 70, height 39, diam. 21 mm.

Chattahoochee River, Georgia, west to Little Patsaliga Creek,

Alabama.

Type locality, Creeks, Columbus, Ga.

Umo columbensis Wea, Pr Aco N.Sct Phila; xs 1657, pase;
JimAcoNS Sct Phila, PVs 18585 p.75, "pl. iv; tie 5c Obs
VI, 1858, p. 75, pl. xiv, fig. 55 SIMPSON, Syn., 1900, p. 741.

Margaron (Umo) columbensis L¥a, Syn., 1870, p. 50.

Unio columbiensis Parrri, Conch. Sam., HI, 1890, p. 148.
Exceedingly close to forms of U. tetralasmus on the one

hand and U. obesu

a

on the other. It is generally a solider
shell than either, its teeth are normally considerably heavier
and it differs a little from either in texture in an almost in-
describable way. Its color is colder, not so warm and soft as
that of tetralasiius or obesus.

UNIo ospesus Lea.

Shell rhomboid, subinflated or inflated, subsolid, inequilat-
eral; beaks full, high, their sculpture numerous ridges which
are strongly curved up behind; posterior ridge high, rounded,
ending in a point, rarely a feeble biangulation at or very near
the base of the shell; posterior slope with two faint, radial
sulci, obliquely truncated; surface with irregular growth
lines; epidermis tawny-brown to dark brown, longitudinally
wrinkled, often cloth-like; pseudocardinals generally small,

UNIO TEL

compressed or subcompressed, two in the left valve, one and
a vestige of a second in the right; laterals remote, curved:
muscle scars large, the posterior ones decidedly so, well mark-
ed; nacre lurid purplish.
Length 84, height 50, diam. 33 mm.
Length 108, height 66, diam. 37 mm.
Length 113, height 59, diam. 40 mm.
Southern Virginia probably ; South to Georgia.
Type locality, Georgia.
?Unio carolinensis Bosc, Hist. Nat. de coq., 1824, ILI, p. 139,
pl. xxi, fig. 2.—Cuenv, Ill. Conch., 1843, pl. xv, fig. 4.
Umio obesus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 96, pl. x11,
fig. 26; Obs., I, 1834, p. 106, pl. x11, fig. 26—HaAn_ey, Biv.
Shells, 1843, p. 198, pl. xxu, fig. 34—CuHENu, Il. Conch.,
1858, pl. xvut, figs. 4, 4a, 4b.—Kustrer, Conch. Cab. Unio,
1861, p. 196, pl. Lx, fig. 2—Rereve, Conch. Icon., XVI,
1864, pl. xvii, fig. 84.—?SowerRsBy, Conch. Icon., XVI, 1866,
pl. xxxviir, fig. 212—Srmpson, Pr. U. S. Nat. Mus., XV,
Is024pu42e,; Plwie xvid fe. Oy LIK Mies. 1. 2ad ee on 3\
Syn., 1900, p. 741.
Margarita (Unio) obesus Lea, Syn., 1836, p. 30; 1838, p. 21.
Margaron (Unio) obesus Lra, Syn., 1852, p. 32; 1870, p. 50.
Unio declizns Conrap, Monog., V, 1836, p. 45, pl. xxu1, fig. I.
Unio meptis Lea, Tr. Am. Phil. Soc., X, 1 te po 2or pl. Kv:
Hee ODS Vs Lose, p17, pl. KV. fig.
Margaron (Unio) ee MEAS Oyi., 1952, p. 31); 1870, p. 50.
Unio hebes Lea, Tr. Am. Phil. Soc., X, 1852, p. 267, pl. xviit,
fs. .20 Obs: V5 L852, p. 23, pl. XVIII, fig, 21
Margaron (Umo) hebes Lea, Syn., 1852, p. 26; 1870, p. 51.
Unio nvularis Conran, Pr: Ac. N. Sci. Phila., V1, 1853,;p. 257.
Unio cur Leavy ProAtcs Ne Sem Phila.) Vi, 2861j0p, 393 Jl:.Ac
Ne oGl. inlay Vi. 1862, p.oa, pl. xii, fic. 2415 Obs. VIEL,
1862, p. 97, pl. x11, fig. 241.
Margaron (Unio) cicur Lma, Syn., 1870, p. 52.
Unio sheet ean (part) ric. IN: Ser Phila:, XV, 1863;
p. coli Ac: N.-semiPhiae Vi. 1866, -p. 22; ply vil, fis: 20
Obs., XI, 1 ee p. 26, pl. vis, fig. 20.
Margaron (Unio) squalidus Lasa, Syn., 1870, p. 51.

712 UNIO

Unio jewetin Lea, Pr. Ac. N. Sci. Phila., XI, 1867, p. 81; Jl.
Ac. N. Sci. Phila., VI, 1868, p. 276, pl. xxxvu, fig. 89; Obs.,
XII, 1869, p. 36, pl. xxxvn, fig. 89.

Margaron (Unico) jewettti Lea, Syn., 1870, p. 51.

Unio pawensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 161;
Jl. Ac. .N..Sei. Phila, Vl; 1808, p..302, pla xy, ie. tia Obs.
AT, 1860; p62. pl. xa hee 114i

Margaron (Unio) pawensis LEA, Syn., 1870, p. 51.

A very variable species in size, color and form. Some of
the material from South Carolina and Georgia has rather a
thin reddish-tinted epidermis. Occasional shells are nearly
evenly elliptical, being only slightly rhomboid, from these
there 1s every variation to material that is incurved on the
base, decidedly rhomboid and having the posterior point drawn
down to a beak. This latter character is the result of maturity
or old age and is seen in many other unrelated Uniones.

It may be that the Unio carolinensis of Bose is the same as
Lea’s U. obesus. Dr. Lea thinks it is Margaritana margariti-
fera, but Bosc did not visit any region inhabited by that species,
and the figure seems to show lateral teeth. I confess that I
am not able to determine what species Bosc refers to and I
think it is better to use the name given by Lea.

The figure given by Conrad for U. diclivis seems to me to
be that of a typical obesus and not that of any form of tetralas-
mus.

The type locality was originally given as York River, Va.,
but Lea (Obs., I, p. 118) states that this was a mistake and that
the types were collected by Le Conte in Georgia..

Var. blandingianus Lea.

Shell dark and rough, often cloth-like, rhomboid, frequently
drawn out to a beak at the hinder end. This beak sometimes
extends below the rest of the base line.

Florida; extending northward into southern Georgia.

Type locality, St. John’s River, Fla.

UNIO 713

Unio blandingianus Lea, Tr. Am. Phil. Soc., V, 1834, p. Lol,
pl. xv, fig. 44; Obs., I, 1834, p. 213, pl. xv, fig. 44.—ConrRaD,
Monog., V, 1836, p. 46, pl. XXIIL, fig. 2.—Han_ey, Biv.
Shells, 1843, p. 200, pl. xxu, fig. 1.—Kuster, Conch. Cab.
Unio, 1852, p. 36, pl. vi, fig. 2—Sowersy, Conch. Icon.,
XVI, 1866, pl. xxxv, fig. 187.

Margarita (Unio) blandingianus Lia, Syn., 1836, p. 32; 1838,
Pp. 22:

Margaron (Unio) blandingianus Lua, Syn., 1852, p. 33; 1870,
Pp. 54-

Unio obesus var. blandingianus SIMPSON, Syn., 1900, p. 742.

Unio rivicolus Conrav, Am. Jl. Conch., IV, 1868, p. 280, pl.
Xvill, fig. 4.

In Florida and Southern Georgia the obesus is almost always
dark and rough, the epidermis becoming thick, often cloth-like
and the form is decidedly rhomboid. There is a gradual
change from the type to this form. The Unio rivicolus ot
Conrad belongs here instead of under the type.

Var. paludicolus Gould.

Shell small, usually narrower in front, rather thin to sub-
solid, greenish-brown to blackish, sometimes biangulate be-
hind and having a double posterior ridge. Nacre bluish-white,
dingy purplish or even coppery.

Length 42, height 22, diam. 12 mm.

Florida, various localities.

Type locality, Florida Everglades.

Unio paludicolus Goutp, Pr. Bost. Soc. Nat. Hist., II, 1845,

P- 53-

Margaron (Unio) paludicolus Lua, Syn., 1852, p. 33; 1870. p.

54-

Unio obesus var. paludicolus Stmpson, Syn., 1900, p. 743-
Unio paludicolor Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p-

254.

This form differs from the type merely in degree, not in
any real characters. It has never been figured, but the Lea col-
lection contains specimens donated by Dr. Gould from the
Everglades, the type locality, and some of these are almost

714 UNIO

exact miniatures of the larger U. obesus. Occasionally the
anterior end is considerably narrowed and the posterior ridge
becomes somewhat double. I have found such specimens in
Manatee County, Florida.

UNIO BISSELLIANUS Lea.

Shell long rhomboid, subsolid or solid, subinflated, inequi-
lateral; beaks somewhat elevated, moderately full, their sculp-
ture a few strong ridges that curve up decidedly behind ; pos-
terior ridge full, rounded, sometimes having above it a couple
of low, radiating ridges; dorsal slope decidedly obliquely
truncated ; base line nearly straight ; dorsal line curved a little;
anterior end rounded; surface with concentric growth lines;
epidermis dull greenish, concentrically wrinkled, usually
slightly rayed, having a broad faint ray on the posterior ridge
and two narrower ones above it; pseudocardinals subcom-
pressed, two in the left valve and one in the right; laterals
curved; muscle scars shallow; nacre having a lurid purplish
tint, iridescent behind.

Length 70, height 40, diam. 22 mm.

Type locality, Bissel’s Pond, Charlotte, North Carolina.
Unio bisselianus Lra, Pr. AGN. Sci. Phila. Xe 1867, p. S15

jt. Ac. N.; Sei. Phila, V1, 2868.9) 277. plo xevin ie oo,

Obs., XII, 1860, p. 37, pl. xxxvu, fig. 90.—Simpson, Syn.,

1900, p. 743.

Margaron (Unie) bisselianus Lea, Syn., 1890, p. 50.

Close to forms of U. obesius, but the epidermis is colder, not
so rough and is rayed behind. I have before me a shell said
to come from Lucile, Lauderdale County, Mississippi, received
from Mr. Berlin H. Wright, which approaches U. bissellianus
more nearly than anything, but I do not feel safe in referring
it to that.

Section Mrcronatas Simpson, 1900.

Micronaias SIMPSON, Syn., 1900, p. 743.

Shell small, oval, a little produced near the posterior base,
with a moderate posterior ridge and pointed near the base be-
hind: beaks rather prominent, the sculpture being apparently

UNIO 715

rather fine, irregularly concentric ridges, having a tendency to
fall into two loops; the whole surface strongly and closely con-
centrically ridged; pseudocardinals compressed, high, slightly
curved upward; laterals compressed, curved; beak cavities
moderately deep; nacre whitish; anterior muscle scars deep,
rough ; posterior well marked.

Animal with the marsupium pad-like, occupying all but the
extreme posterior part of the outer gills; branchiz elongated,
wider behind, inner the larger throughout, free from the ab-
dominal sac or united to it; palp1 large, rounded behind ; man-
tle with thickened border; anal opening crenulate.

Type, Unio aratus Lea.

A peculiar group of small species, which conchologically
resemble some of the Plagiolas of the Central American region.
But in the gravid animals the outer gills are filled throughout
their entire length with embryos. forming a pad-like marsu-
pium. That of Plagiola is very different, consisting of a limited
number of ovisacs in the hinder part of the outer gills, which
are separated from each other by sulci.

UNIO FALLACIOSUS Nn. sp.

Shell small, subtriangular, somewhat inflated, rather solid
with high beaks, whose sculpture consists of a few moderately
coarse ridges, which are corrugated and somewhat doubly
looped; from the beaks there is an almost straight oblique
truncation to the anterior and posterior points; the base line
is evenly rounded ; posterior ridge strong; surface everywhere
covered with coarse, rather sharp, concentric sculpture, tawny,
sometimes greenish-yellow or vellow-green, often having a few
faint ravs at the beaks; left valve with two rather high, sub-
compressed, ragged and, sometimes slightly refiected, pseudo-
cardinals and two laterals; right valve with two pseudocar-
dinals, the upper feeble, and one lateral; beak cavities shal-
low, showing a few scars; muscle scars moderately impressed :
nacre soiled white to salmon.

Length 32, height 23, diam. 17 mm.

Nicaragua.

716 UNIO

This form has apparently passed as Unio aratus and some
time ago I believed it to be the young of Quadrula spheniopsis.
I am now satisfied that it is neither of these, as it is a solider,
higher, rather more inflated shell than the former, and has
coarser, sharper sculpture, while the outline is less quadrate
than that of spheniopsis at the same age.

Unio aratus Lea.

Shell small, subsolid, suboval to subtriangular, somewhat
convex, with a well-defined posterior ridge, which ends behind
in a rather sharp point below the median line, anterior end
slopingly subtruncate above, rounded below ; base rather evenly
rounded ; epidermis yellowish-tawny, sometimes tinged brown-
ish or greenish and everywhere strongly and irregularly sul-
cate; left valve with two somewhat compressed, ragged pseu-
docardinals and two lamellar laterals; right valve with one
pseudocardinal, with a vestigial one above it, and one lateral,
all the pseudocardinals often slightly recurved; beak cavities
shallow, showing a few posterior scars ; muscle scars not deep ;
nacre dirty white or yellowish.

Tength 28, height 18, diam. 13 mm.

Length 34, height 20, diam 15 mm.

Central America.

Unio aratus ea, Disc. 12 Uniones, 1843; Tr. Am. Phil. Soc.,
LX, -1845, p. 282, pls xn, ies T2ag0Obs 7 AVen e148. ps 40. pL
XL, fig. 12—Sowersy, Conch. Icon., XVI, 1868, pl. Lxiv,
fig. 320.—SIMPSON, Syn., 1900, p. 744.—VON Marrens, Biol.
Cent. Amer., Moll., 1900, p. 499, pl. xxxIx, figs. I, Ia, 1D, 2,
3, 34, 30.

Margaron (Unic) aratus L&a, Syn., 1852, p. 28; 1870, p. 35.

Unio nuculinus Puitiprr, Zeit. fiir Mal., V, 1848, p. 176.—
Simpson, Syn., 1900, p. 607.—von Marvens, Biol. Cent.
Am., Moll., 1900, p. 509, pl. xxx1x, fig. 6, 6a, 6b.

This species is a variable one and some of the specimens
are much more elongated than others and occasional shells are
fuller at the posterior base than others and these are probably
females. I have examined the gravid animal of what I believe

UNIO Fy

to be this species and it seems to be a true Unio, the marsupium
occupying nearly the entire length of the outer gills as a smooth
pad. I have not been able to examine the beak sculpture of this
species.

I am quite sure that Philippi’s Umo nuculinus which has
been figured for the first time by von Martens in the Biologia
is a delicate young female aratuts.

UNIO GRANADENSIS Lea.

Shell rather small, rhombovate, subintlated, somewhat solid,
with a well-developed posterior ridge; surface slightly and ir-
regularly concentrically sulcate, covered with a dark brown or
blackish epidermis, which sometimes appears slightly silky
when fresh; dorsal line strongly curved; basal line less curved
or nearly straight ending in a rounded point behind at a level
with or just above the base line; anterior end sometimes a
little angulate but rounded; left vaive with two ragged, sub-
compressed pseudocardinals and two short, curved laterals;
right valve with one pseudocardinal, sometimes with a vestigial
one above, and one lateral, sometimes with a feeble second one
below it; beak cavities moderate; muscle scars impressed ;
nacre whitish or yellowish, soiled.

Length 37, height 24, diam. 18 mm.

Lake Nicaragua.

Umio granadensis Lra, Pr. Ac. N. Sci. Phila., XII, 1868, p. 95;
Jl. Ac. N. Sci. Phila., VI, 1868, p. 203, pl. x11, fig. 103; Obs.,
XII, 1869, p. 53, pl. xLu, fig. 103.—Simpson, Syn., 1900, p.
744-

Margaron (Unio) granadensis Lea, Syn., 1870, p. 35.

The male and female shells do not appear to differ greatly,
the latter is probably a little fuller at the base. This species
is larger, solider and more inflated than U. aratus and may be
always distinguished from it by having a nearly black epider-
mis, while that of aratus is much lighter colored. Yet the re-
semblance is sometimes rather close and Dr. Lea placed several
young granadensis in the tray containing his aratus. I am
inclined to believe that von Martens has figured one or two
specimens of this species for aratus.

718 UNIO

Species INCERT/E SEDIS
UNIO PAJAKOMBOENSIS Bullen.

“Shell solid, ovate, inflated, slightly gaping at both ends;
epidermis shining, yellow-brownish-green; valves subrotund,
sloping posteriorly, concentrically substriate; unbones close
together, eroded; cardinal tooth of the right valve long, erect,
sloping, almost smooth. sometimes with a small, auxillary
parallel tooth situated near the external margin; lateral tooth
elongate ; lateral teeth of the left valve elongate and of equal
length; cardinal tooth nearly obsolete; anterior cicatrix deep,
posterior less impressed.

Length 77, height 51.5, diam: 37 mm.” (Bullen).

Type locality. Pajakombo, Sumatra.

Unio pajakomboensis Butien, Pr. Mal. Soc. London, VII,

1906, p. 15, pl. 1, figs. 9-1T.

Schizocleithrum pajakomboense Haas, Conch. Cab. Unio,

TOU: plexi NSSs45 0:

Haas has recently, (Nachr. Deutsch. Mal. Ges., 1913, p. 36),
made this species the tvpe of a new genus, Schizocleithrum.

UnIo TAUMILAPANUS Conrad.

“Oblong, somewhat compressed; substance of shell thick
anteriorly and over the umbo; disks flattened; ligament mar-
gin nearly parallel with basal margin; umbo decorticated ;
within pure white.

Allied to U. miger Raf., but more reendlen oblong and very
white inside.” (Conrad).

Type locality, San Juan River, Taumilapas.

Unio taumilapanus Conran, Pr. Ae. N. Sei. Phila., XII, 1855,
p. 256.—Le, Syn..-1870, p. 65.—von Martens, Biol. Cent.
Am., Moll., 1900, p. 521.

Unio taumilapasensis, Fiscuer and Crosse, Miss. Scient.
Mex., Moll., II, 1894, p. 621.

This species, which was accidentally omitted from the
Synopsis, T have not been able to identify. Both Fischer and
Crosse and von Martens have been equally unsuccessful. Con-
rad identifies niger Raf. with crassidens Lam. and incrassatus
Lea.

UNIO 719

Unio sriarti Dautzenberg.

“Shell solid, transversely oval, narrowed in front, expanded
posteriorly. Beaks at the anterior third of the length. Ante-
rior extremity short, rounded and compressed; posterior end
expanded, inflated and very obliquely truncate. Surface with
irregular striz and lines of growth. An obtuse ridge ex-
tends from the beaks to the base of the posterior truncation,
and the posterior slope is ornamented with numerous, oblique
folds, curved and more or less chevroned near the margin.
Some similar, but less pronounced, folds appear on the an-
terior region, near the beaks. Interior of the valves
nacreous, very finely shagreened. Cicatrices of the anterior
muscles round, deep and with a small scar at the base of and
behind the principal one. Cicatrices of the posterior adductors
subtrigonal. superficial. Hinge not very thick, with two, short
cardinals in the right valve, slightly roughened, separated by
a narrow groove, and a long, curved, lamellar lateral; two
cardinals in the left valve, the anterior short, compressed,
roughened and erect, the posterior obsolete, and two lamellar
laterals, curved and quite close together, the upper more prom-
inent. Color uniform olive-yellow, more or less tinged with
black; nacre bluish-white. Ligament deep yellowish-brown,
quite prominent.

Length 54, height 74, diam. 32 mm.” (Dautzenberg)

Type locality, La Lufoi, Congo Free State.

Unio briarti DAUTZENBERG, Ann. Soc. Mal. Belgique, XXXVI,

T90T, p- 6, pl. 1, fies. 3, °4.

UNIO MALGACHENSIS Germain.

“General form of the shell an elongate-siliquiform; valves
strongly twisted in the infero-posterior region; anterior end
very short, obliquely rounded at the base; posterior portion
a little more than three times as long as the anterior, sub-
rectilinear-elongate, rounded at the end; beaks very large, very
prominent, incurved anteriorly ; ligament not large, but slightly
projecting; dorsal margin nearly straight; basal margin
straight, slightly sinuous in the middle curving upwards
towards the posterior end; dorsal and basal margins practically

720 UNIO

parallel: hinge and muscular impressions unknown. Epider-
mis of a clear yellowish-chestnut, almost gray towards the
beaks and dark brown posteriorly ; strize not strong, very irreg-
ular.

Length 11.5, height 4.75, diam. 3.5 mm.” (Germain).

Type locality, Madagascar.

Unio malgachensis GERMAIN, Bull. Mus. Hist. Nat., 19g1t, p.

138; pla, figs. 3) 4555:

“The unique example collected by M. Geay is a young shell
found alive. The necessity of keeping it intact for the collec-
tion of the Museum d’histoire naturelle has prevented me from
studying the hinge and muscular impressions. Consequently
it is impossible for me to decide definitely as to what subgenus
the species should be referred. I have thought it necessary
to describe and figure this Unio, which will certainly be found
again some time and which shows that the island of Madagas-
car has a more varied fauna of fresh-water pelecypods than
has heretofore been believed.”

UNIo STOLATUS von Martens.

“Shell elongate, compressed, concentrically striate; epider-
mis brown, opaque; anterior extremity shortly rounded-trun-
cate; posterior elongate, rostrate; wing slightly elevated; an
obtuse ridge extends backwards and downwards from the
beaks, behind which the posterior slope is sculptured with
small, oblique, decurrent folds; upper posterior margin very
oblique, lower posterior margin somewhat rounded; ventral
margin. moderately curved in front, straight in the middle,
slightly ascending posteriorly ; cardinal teeth thin, compressed,
parallel with the dorsal margin, obliquely sulcate above; nacre
bluish, pale yellowish towards the umbones. Beaks at one-
fourth of the length.

Long. 72, alt. vert. 32, alz 39, diam. 17.5 mm.” (von Mar-
tens).

Type locality, Lake Danau Baru, Sumatra.

Unio stolatus VON Martens, Nachtr. Deutsch. Mal. Ges., 1goo,
pis.

“Only a single example, rather thin-shelled, beaks only
slightly eroded.”

UNIO 7 PAN

Unio SZECHENYII Neumayr.

“Shell thick, very inequilateral. oval wedge-shaped, rounded
in front, very much smaller behind, pointed, very much trun-
cated, gaping; inflated anteriorly ; beaks not prominent, placed
very far forward, much eroded. Hinge moderately strong; in
the right valve a single, triangular, jagged cardinal tooth;
in the left a small lamelliform anterior cardinal and a triangu-
lar posterior one, which meet above at an obtuse angle. ‘The
lateral teeth in both valves are long. Muscular impressions
confluent, equally jiarge, the anterior deep, the posterior shal-
low. Nacre white. Epidermis blackish-brown.

Length 96, height 45, diam. 31 mm.” (Neumayr).

Type locality, Pojang Lake, Kiu-kiang, Kiang-si Province,
China.

Unio ssechenvii Neumayr, Ergebnisse d. Reise Szecheny

Ostasien. IT, 1898, p. 642, pl. u, fig. 1.

“Among the described species. Unio corderti Heude is the
nearest, but this species is very easily distinguished by the very
pronounced gaping of the shell, greater size, more pointed
form and darker epidermis.

Unio pazi I,ea differs by its distinctly keeled and much less
obliquely truncate posterior end, lamelliform cardinal teeth
and very different color of the epidermis, moreover the descrip-
tion does not say that the shell gapes posteriorly.”

Unio FLExIcosus Neumayr.

“Shell thick, inequivalve, very inequilateral, long oval,
twisted, rounded in front, slightly keeled, pointed, obliquely
truncate behind. Beaks not prominent, well anterior, much
eroded. Hinge, in the left valve, which alone is known, with
two very high, much compressed, jagged cardinal teeth, which
unite and form a continuous ridge in a straight line, lateral
tooth very long and strong. Anterior muscular impressions
deep; posterior confluent, larger, very shallow. Nacre white.
Epidermis blackish-brown.

Length 95.5, height 43 mm.” (Neumayr).

7220 UNIO

Type locality, Pojang Lake, Kiu-kiang, Kiang-si Providence,
China.

Unio flexvicosus NeuMAyR, Ergebnisse d. Reise Szecheny Ost-

asien, IT, 1898, p. 642, pl. m1, fig. 2.

“Unio flexicosus, it is true, is known only by a single left
valve, but this has such a remarkable character and so interest-
ing a form that it is entitled to be made the type of a new
species. In the small group of twisted unios, U. picinalis
Heude is the nearest, but ditfers at first glance by its much
stronger twist. Other species, such as U. contortus Heude and
triformis Lleude differ still more.”

Unio SUPERSTES Neumayr.

“Shell oval, thick, inequilateral, somewhat inflated, slightly
angulate posteriorly and very little truncated. Beaks situated
at the first third of the length, not prominent, somewhat erod-
ed. In the left valve one moderate, triangular cardinal tooth
and in front of it a very feeble lamelliform one, in the cavity
between them is an elevated ridge, which shows that the
cardinal tooth of the right valve is bifid. Lateral tooth long
and strong. Anterior muscular impression distinct, deep, pos-
terior slightly larger and much weaker. [pidermis olive-
brown. Nacre white. The size can not be accurately stated,
as the specimen is imperfect.” (Neumayr).

Type locality, Tali-fu, Province of Yunnan, South China.
Unio superstes Nwumayr, Ergebnisse d. Reise Szecheny Ost-

asien, Ti Sreo8; .p. 642" pl. me.

“Of this species I have only a single, somewhat damaged
valve. I would not have described a new species from such
a poor specimen, if it were not that, on account of its very
close relationship to the European Pliocene types, it 1s import-
ant to the interesting study of the Chinese fresh-water fauna.
It stands so exceedingly close to Unio nicolaianus Brus. from
the middle Paludina-beds, the ancestral form, from which a
whole race of other species has been evolved, that one, watch-
ing for the greatest difference, would find it very difficult to
find any variation between them, the beaks in the first species

UNIO "| gaa

{nicolaianus) are very slightly further forward, the anterior
end is somewhat less rounded and the cavity between the
cardinal teeth of the left valve a very little smaller and without
the elevated ridge. These insignificant differences are imma-
terial and there can be no error in referring to the intimate
relationship between a //nio of the European Tertiary and a
living form from the Chinese or American area.”

UNIO PANTOENSIS Neumayr.

“Shell thin, rather small, inequilateral, quadrate, slightly in-
flated, rounded in front, truncate behind, with a slight appear-
ance of being winged; dorsal margin slightly curved; ventral
margin straight. Surface with irregular growth lines, angu-
larly wrinkled at the beaks. Beaks not prominent, situated in
the first third of the length. Hinge with moderately long,
strong laterals: in the right valve a single, rather feeble, for-
ward projecting, lamelliform cardinal tooth; in the left valve
two similar ones, of which one begins under the beak and
reaches far outward, while the other is direct. Muscular im-
pressions very faint. Nacre bluish. Epidermis olive-brown.

Length 34, height 21, diam. 12 mm.” (Neumayr).

Type locality, Panto, Yunnan.

Unio pantoensis NeuMAvyR, Ergebnisse d. Reise Szecheny Ost-

asien, II, 1898, p. 644, pl. 1, fig. 5.

Unto HERES Neumayr.

“Shell oval, thick, slightly inflated, inequilateral, narrower
in front, beaks situated in the front third of the shell, not prom-
inent, the greatest breadth being behind the beaks. Shell very
indistinctly keeled posteriorly and somewhat truncated. Beaks
somewhat eroded. Hinge of the right valve with a moderately
stout cardinal tooth, striate on the upper side and a long,
strong lateral. eft valve unknown. Anterior muscular im-
pression smail and deep, posterior somewhat larger, but very
faint. Epidermis olive-brown. Nacre white.” (Neumayr).

Type locality, Lake near Tali-fu, Yunnan.

Unio heres NeumMayr, Ergebnisse d. Reise Szecheny Ostasien,

IT, 1898, p. 644, pl. 1, fig. 6.

724 UNIO

“Unio heres is at first glance extraordinarily like Unio
suferstes, but, on careful consideration, it can easily be dis-
tinguished by its form, smaller in front and truncate behind,
the greatest width being behind the beaks and the less promi-
nent beaks. The hinge of the two species must also be differ-
ent, since from the condition of the left valve in U. superstes
the cardinal tooth in the right valve must be a little stronger,
lower and split in the middle.

This interesting species is like the preceding (superstes),
very closely related to the Slavonic Unio nicolaianus. Only
a single right valve is before me.”

UNIO KOoBELTI Neumayr.

“Shell thin, long egg-shaped, inequilateral, slightly inflated ;
beaks situated in the first fourth of the length, not prominent.
greatly eroded; somewhat truncated in front; dorsal margin
curved, higher behind the beaks, where is the greatest height.
Ventral margin nearly straight; posterior end small, rostrate.
Cardinal teeth striate, lamelliform, very. thin; laterals long,
striate, lamelliform, very feeble. Muscular impressions very
faint. Epidermis blackish-brown. Nacre white.” (Neu-
mayr).

Type locality, Kiu-kiang, Province of Kiang-si, China.
Unio kobelti Neumayer, Ergebnisse d. Reise Szecheny Ost-

asien, II, 1808, p. 645, pl. 111, fig. I.

“Unio kobelti stands rather alone; Unio pfisteri Heude is
like it in a general way, but in that the beaks are somewhat
more posterior, the posterior part is keeled, the basal margin
rounded, but especially it differs in the hinge as the character-
istic lamelliform cardinal teeth are wanting. Monocondylus
nankingensis Heude resembles it only in the external surface.
Pseudodon secundus Heude is like it only in the external con-
tour ; the hinge is entirely different.”

UNIO ZAMBESIENSIS Preston.

“Shell subtrapezoidal, deep rich brown, sculptured, espe-
cially above, with wavy zigzag ridges and below with coarse,

UNIO 725-.

irregular, concentric lines of growth; anterior side obliquely
rounded; posterior side somewhat squarely rounded.

Alt. 22.5, length 35 mm.” (Preston).

Type locality, just above Victoria Falls, Zambesi River.
Unio zambesiensis Preston, Pr. Mal. Soc. London, VI, 100s,

p. 301, text-fig. 1.

UNIO ANGONIENSIS Preston.

“Shell ovate, slightly angled posteriorly, covered with a
blackish-brown, lJaminiferous periostracum; sculptured with
closely set, irregular, concentric growth-lines, and posteriorly
with curved, transverse, interrupted, slightly nodulous riblets:
umbones much eroded, rather large, moderately prominent :
dorsal margin somewhat ascending, scarcely arched; ventral
margin nearly straight; anterior side abruptly rounded; pos-
terior side sloping above, then angled and descending sharply
below ; lateral teeth elongate curved; cardinal tooth in right
valve elongate, erect and jagged anteriorly, partially cleft
posteriorly ; cardinal tooth in left valve somewhat triangular.
broad, tuberculous in the middle, erect and jagged at the sides;
anterior adductor scars deeply impressed, ovate; posterior
adductor scars light ; interior of shell nacreous, pink anteriorly,
livid bluish posteriorly.

Length 26, lat. 39 mm.” (Preston).

Type locality, Angoniland, British Central Africa, to the
south of Lake Nyassa.

Unio angoniensis Preston, Ann. Mag. Nat. Hist., (8), VI.

1910, p. 50, pl. tv, fig. 5.

UNIo CHARON Preston.

“Shell elongately ovate, slightly gaping at both sides, covered
with a black periostracum, corrugately sculptured towards the
umbonal region and marked below with irregular, concentric
ridges; umbones eroded, moderately large, not prominent;
dorsal margin curved; ventral margin slightly constricted in
the middle, otherwise straight; anterior side rather produced,
angularly rounded; posterior side elongately produced, sharply
rounded ; lateral teeth in both valves elongate, curved ; cardinal

720 UNIO

tooth in right valve elongate, rather fine, rising considerably in
the middle: cardinal tooth in the left almost obsolete, serrated
anteriorly ; anterior adductor scars deep, somewhat square in
shape; posterior adductor scars scarcely impressed.
Length 52, height 26.5 mm.” (Preston).
Type locality, Silongwe, British Central Africa.
Unio charon Preston, Ann. Mag. Nat. Hist., (8), VI, 1910,
p. (60, pl. 1%, fies 6;

UNIo SILONGWEENSIS Preston.

“Shell differing from U. charon by its narrower form and
somewhat more acuminate posterior side, lighter texture,
much smoother, concentric sculpture, and paler color, the
periostracum being of a pale yellowish-brown color; the mus-
cular scars are much larger and, in the case of the anterior
adductor, more deeply impressed.

Long: 26.5, Jat. 52 am.7).Cereston),

‘Type locality, Silongwe, British Central Africa.

Unio vicmus Preston, Ann. Mag. Nat. Hist., (8), VI, 1910, p.

60; ipl ivestion 7.

Umo silongweensis Preston, Naut., XX VI, 1912, p. 35.

“Vicmus’ having already been used for a Unio by Lea in
1856, Mr. Preston has proposed another name for his species.

Unio CHOZIENSIS Preston.

“Shell small, squarely ovate, moderately convex, covered
with a blackish-brown periostracum, sculptured with fine, con-
centric striae and rather coarse, transverse, corrugate ridges,
which become finer posteriorly ; umbones not prominent; dor-
sal margin sloping in an anterior direction; ventral margin
slightly rounded; anterior side descending somewhat abrupt-
ly; posterior side rather acuminately rounded; lateral teeth
elongate, straight; cardinal teeth in right valve weak, jagged,
erect anteriorly, bifurcate posteriorly; cardinal teeth in left
valve elongate, finely jagged, cleft anteriorly; muscular scars
deeply impressed anteriorly, scarcely apparent posteriorly ; in-
terior of shell iridescent, bluish-white.

Long 1G25elate 25mm.” “Creston ).

UNIO 727

Type locality, Chozi River, a tributary of the Chambzi, flow-
ing into Lake Bangweolo from the east.
Unio choziensis Preston, Ann. Mag. Nat. Hist., (S), VI, 1910,
p:-60,,pE iv, fig. 8.

Unto GeRETI Preston,

“Shell ovate, somewhat tumid, covered with a dark brown,
silky periostracum and sculptured with fine, rather closely set,
concentric lines of growth; umbones slightly eroded, prom-
inent:; dorsal margin nearly straight; ventral margin scarcely
rounded: anterior side angled above, obtusely rounded below ;
posterior side sloping obliquely, sharply rounded below; lat-
eral teeth short anteriorly, elongately curved posteriorly ; an-
terior cardinal tooth in right valve short, rather square, erect,
jagged, incised on the outer side; median cardinal tooth very
small; posterior cardinal rather small, projecting; anterior
cardinal in left valve bluntly triangular, incised posteriorly ;
posterior cardinal bifurcate. thus presenting the appearance of
a double tooth; anterior adductor scars ovate, well impressed ;
posterior adductor scars moderately impressed; interior of
shell pale bluish-white, somewhat iridescent.

Length 36.5, lat. 61 mm.” (Preston).

Type locality, Lake Tanganyika.

Unio gereit Preston, Ann. Mag. Nat. Hist., (8), VI, 1910, p.

Gi, pl. ty, feo.

UNIO: SHIREENSIS Preston.

“Shell ovate, moderately tumid, covered with a pale, reddish-
brown, rather thin periostracum, which becomes thicker, fol-
iaceous, and darker in color posteriorly, both valves sculptured
with coarse, concentric growth-lines; umbones much eroded,
very smal!; dorsal margin somewhat arched; ventral margin
shghtly rounded; anterior side rounded above, sloping below ;
posterior side bluntly rostrate ; anterior lateral teeth very short ;
posterior laterals long and straight, slightly serrated; cardinal
teeth curved, massive, jagged, especially in the left valve; an-
terior adductor scar deeply excavated, squarish; posterior ad-
ductor scar irregularly triangular, not deeply impressed; in-

728 UNIO
terior of shell iridescent, pale pinkish, shading to bluish-white
towards the ventral, anterior and posterior margins.
Long. 21; lat. 37 mm.” (Preston).
Type locality, Shiré River, at a point from 3 to 4 kilometres.
to the south of Lake Nyassa.
Unio shireensis Preston, Ann. Mag. Nat. Hist., (8), VI, 1910,
De OL, spr me, fo i:

UNIO SWINHOEI “Reeve” Sowerby.

“Shell broad, oblong, inflated, thin, bluish-white within,
smooth without, obscurely blackish-olive, anterior side rather
rounded, ventral margin inflated, posterior side wide, dorsal
margin elevated, dorso-lateral margin rather straight, umbones.
depressed.”” (Sowerby).

Type locality, Formosa.

Unio swinhoe: Reeve MS., Sowersy, Conch. Icon., XVI, pl. -
XLII, fig. 232, May, 1866—H. Apams, P. Z. S., 1866, p. 319.
—Pinspry, Pr.) Ac. Nat. Sci. Phila:.1905;'p. 750:

Margaron (Unio) swinhoei Lea, Syn., 1870, p. 45.

Cristaria swinhoei (part), SIMPSON, Syn., 1900, p. 586.

“This species was published independently by Sowerby and
Henry Adams. ‘The later author presented his paper to the
Zoological Society at the meeting of May 22, 1866; and since:
a colored plate had to be prepared, it could not well have been
published for some months later. The descriptions, so far as
they go, agree. Sowerby’s figure measures, length 65, alt.
40 mm.; and Adams gives the size as, length 60, alt. 39, diam.
22mm. Sowerby gives the false locality “Camboja’’—a region
where Swinhoe never collected: but then the monograph of
Unio in the Tconica is famous for false localities.

Mr. Simpson, in his Synopsis of the Naiades, 1900, p. 586,
has quoted this species in the synonymy of “Cristaria szwin-
hoei H. Ad.,” which is a totally different species. It may be-
long to Simpson’s genus Lamellidens.’ (Pilsbry).

UNIO PURPURIATUS Savy.

“Transversely oval, slightly oblong, in some specimens with
a littlé tendency towards ovate; dirty vellowish or fuscous, ob-
scurely radiate with blackish-green; beaks in front of the

UNIO 729

middle, hardly raised; posterior edge rounded or rather com-
posed of two nearly rectilinear lines ; anterior margin rounded ;
hinge margin regularly rounded; cavity of the hinge mem-
branes (in front of the beaks) narrow, but very obvious ; basal
margin arquated, a little compressed in the middle, and some-
times almost contracted in that part; within purple, margin

livid, posterior submargin iridescent; primary teeth nearly di-

rect, rather thick, striated; lateral teeth hardly extending be-

yond the sinus of the hinge margin.

Var. a. Within white.

Var. b. Within dull yellowish,

Length 3.1, height 1.6, diam. over .9 inches.” (Say, emend-
ed).

Type locality, a stream a few leagues from Vera Cruz, Mex-
ico.

Unio purpuriatus SAy, New Harm. Diss., 1831.—Conrap, Pr.
Ae Nat. Sat Phila, VI; 1853, p.. 255-

? Unio medellinus FiscHerR and Crossr, Miss. Sci. Mex.,
Moll. II, 1894, p. 603.—von Martens, Biol. Cent. Am.,
Moll., 1900, p. 517.—SIMPSON, Syn., 1900, p. 592.

Unio (Lampsilis?) purpuriatus Frierson, Naut., XXV1, 1912,
p. 22; pl. 111; figs. 4, 5.

“It resembles U. purpureus, nob., but differs in having the
teeth more direct; in the lateral teeth being shorter, with re-
spect to the sinus of the hinge margin; in having the greatest
width at the middle of the posterior margin, etc. In the young
and middle-aged specimens the radii are very distinct, but are
obsolete in old specimens. ‘The umbones are widely decorti-
cated in age, but seldom are they so deeply eroded as to dis-
close the waxen-colored stratum. It may be considered as
the Mexicon analogue of the purpureus.” (Say).

This species has never been satisfactorily identified. Say
did not figure it and his types seem to have disappeared. Con-
rad was the first to identify it with the medellinus of Lea. In
this he has been followed more or less dubiously by later writ-
ers and by myself in the Synopsis. Von Martens (1. c., p. 503),
states that there are in the Berlin Museum two specimens from

730 UNIO

the Dunker collection labeled “Unio purpuriatus Say, Mexico,
Anthony,” which agree very well with smaller, scarcely sin-
uated specimens of Unio aztecorum. He also expresses the
opinion that “Say’s description . . . basal margin a little
compressed in the middle and sometimes almost contracted in
that part,” agrees better with U. astecorum than with U. me-
dellinus; but as the American conchologists refer Say’s name
to the latter, I dare not contradict them.”

Mr. Frierson has recently (1. c.) identified with Say’s species
a-series of specimens collected by Hinkley in the Valles River,
near Mecos, Mexico and identified by Dr. Pilsbry as Lampsilis
strebeli Lea.

In this connection I am permitted to quote from a note by
Dr. Pilsbry::

“T considered the question of U. purpuriatus Say when
working on Elinkley’s species and then decided that the descrip-
tion fits medellinus better than anything else, though I agree
with Simpson that the case is too uncertain to use Say’s name.
Of course, it is quite possible that some other species exists,
which we do not know. but | have a specimen of medellinus,
which is very close in measurements, and of the right color,
etc. Hinkley’s shells do not have the rays and none are deep
purple. I consider them strebeli. U. strebeli is certainly dis-
tinct from medellinis.”

It may be added that Fischer and Crosse consider strebeli
a valid species, while von Martens refers it to astecorum as a
variety.

In view of this conflict of opinion, the only thing to do, in
my opinion, is to still leave the form among the “Species
mquirende.”

Unio mMwervensis E,. A. Smith.

“Shell small, inequilateral, rather thin, narrowly gaping at
both ends; rounded in front; narrower and produced behind;
epidermis brownish-olive, with a few, radiating, green lines
on the posterior portion, smooth, but sculptured with growth

UNIO 731
lines and towards the umbones more or less corrugated ; um-
bones eroded. placed well in front; nacre white, iridescent ;
cardinal teeth rugose; laterals thin, elongate; anterior cica-
trices not deep; posterior light, scarcely impressed.

Length 26, height 15, diam. 10.5 mm.” (Smith).

Type locality, Lake Mweru, Central Africa.
Unio mweruensis EF. A. Smiry, Pr. Mal. Soc. London, VIII,

1908, p. 13, text figures.

The following species are of Rafinesque, and | am utterly
unable to make anything out of them:

Unio dilatata, elliptica, fasciata, fragilis, levigata, nervosa,
ziridis, sonata, all in Monograph, 1820; Unio bicolor, calendis,
castaneus, chloris, diaphanus, fontimalis, fulvus, lasmabrachys,
montanus, pallens, platiolus, rivuiaris, rimosus, teneltus, venus,
all in Continuation of Monograph. 1831.

Other indeterminate Unionide of Rafinesque are: Amblema
antrosa, costata, gibbosa, olivaria, rubra, torulosa; Lasmonos
fragilis; Obovaria obovalis, pachostea; Obliquaria triangularis,
attenuata, atroviolacea, bullata, cliffordiana, cuprea, cyphia,
ellipsaria, fasciolaris, flava, flexuosa, lateralis, lineolata, nodu-
lata, obliquata, pusilla, quadrula, sintoxia, sinuata, subrotunda,
all in Monograph, 1820. Bariosta diploderma, ponderosus, wit-
tatis; Epilobasma biloba; Toxolasma cinerescens, cyclips, flex-
us, in Continuation of Monograph, 1831.

The following are also indeterminate and spurious Unios:
Unio tahetianus CatLow and Rerve, Conch. Nom., 1845, p.

64. Is probably U. taitianus Lea.

Unio radula Say, N. Harm. Diss., 1829, p. 323.

Unio plombarius Viit.A, Disp. Conch. Terr. Fluv., 1841, p. 62-
Unio pequottianus Lanstey, Am. Jl. Sci., 1845, p. 277.

Unio tridescens Conran, Cov. of Monog., No. If.

Unio angusta L,AMARCK, An. sans Vert., VI, 1819, p. 80.
Unio conus SPENCLER, Skriv. Nat. Selsk., 1793, p. 60.

Unio delphinus SpENGLER, Skriv. Nat. Selsk., 1793, p. 63.

We: PLEUROBEMA

Unio doumeti LerouRNEUX and Bourcuicnat, Prod. Mal.
Tunis, p. 163.

Unio distortus Bran, Ann. and Mag., 1836, p. 376, ne. 53.

Unio uber Conrad, Am. Jl. Conch., IT, p. 279.

Mya obovata SoLANpER, Portland Cat., p. 100.

Unio specialis Kort, Icon., new ed., XIX, NGI2, pi S,. pk
DXV, fig. 2694.

Unio hyperamblius Kopevr, Icon., new ed., XIX, TOUS, ps has
pl. pxrx, fig. 2701.

Unio diarbekerianus Koxe., Icon., new ed., XIX, 1912, p. 15
pl. Dx1x, fig. 2702.

,

Umio calliopsis Kozutt, Icon., new ed., XIX, 1912, p. 15, pl.
DXIX, fig! 2702.

Umio deschampsi Konrttr, Icon., new ed., XIX, 1912, p. 28,
pl. Dxx1v, fig. 2721. |

Unio raymondopsis Kovetyr, Icon., new ed., XTX, 1912, p. 30,
pl. Dxxv, fig. 2724.

Unio kuwetkensis Kosar, Icon., new ed., XIX, 1912, p. 31,
pl. DXXV, fies 2725:

Umo ancyrensis Kose, Icon., new ed., XIX, 1912, p. 32, pl.
DXXVI, fig. 2727.

Unio ancyrensis var. louisei Korner, Icon., new ed., XIX,
IOT2, p. 32; ‘pl. Dxxv1, fig! 2726.

Unio bitlisensis Koper, Icon., new ed., XIX, 1912, p. 35, pl.
DXXVING es 2731,

Unio raymondi Locarp, Moll. Lacs ‘Tiberiade, p. 208.—Kosett,
Icon., new ed., XIX, 1912, p. 40; pl. pxxx1, fig. 2738.

Genus PLEUROBEMA (Rafinesque, 1820) Agassiz.

Pleurobema Rarrnesour, Ann. Gen. Sci. Phys., Brux, 1820,
p. 313.—ORTMANN, Ann. Car. Mus., VIII, 1912, p. 261.
Shell solid, triangular to rhomboid, usually with a prominent

umbonal region; beaks at or near the anterior end of the shell,

incurved and pointed forward over a small but well-developed

PILEUROBEMA 733.

lunule: beak sculpture coarse, consisting of a few irregular,
often broken ridges, which curve upward posteriorly; pos-
terior ridge present, but low and rounded; epidermis showing
the rest periods plainly, tawny to olive, often ornamented with
rays, which show a tendency to break into square spots ; hinge
rather strong, the plate generally narrow ; pseudocardinals tri-
angular, ragged: laterals reaching nearly or quite to the pseu-
docardinals, double in both valves, in the right valve the inner
being smaller; muscle scars deep, the posterior rounded; cav-
ity of the beaks shallow; nacre silvery ; male and female shells
essentially alike.

Animal having the inner gills much the larger, rounded be-
low, free from the abdominal sac for a part or all of their
length; marsupium occupying the entire outer gills, the ovi-
sacs in some cases seeming to be arranged in pairs; animal
generally yellowish to salmon-red, sometimes more or less
brown or blackish.

Type, Unio clava Lamarck.

The species which I have placed under the generic name
Pleurobema seem to stand between Quadrula and Unio. ‘The
heavy inflated forms of the clava, showalterti and troscheliana
groups approach Quadrula in some cases so closely that it is
difficult to separate them from it. But all have shallow beak
cavities, while those of Ouadrula are almost invariably deep,
and I have no doubt that all carry the young in the outer gills
alone, instead of in all four as the Quadrulas do. On the
other hand many species of the argentea group and a few in
the clava and other groups approach Unio so closely that I
have been at a loss to know where to place them. Most of
the shells of the genus, though not all, have a tawny-colored
epidermis often marked with broken, bright green rays that is
different from the species of either Unio or Quadrula and
nearly all of them are confined to the Ohio, Tennessee and
Alabama River systems. ‘Two or three forms whose relations
are a little doubtful belong in the Atlantic drainage.

ios)

4 PILEUROPEMA

KEY TO SPECIES OF PLEUROBEMA.

Shell with a subvertical median row of nodules.

Epidermis smooth, shining. @sopus.
Epidermis cloth-like or silky, dull. compertum, cicatricosum.

Shell not nodulous.

Epidermis dark greenish-brown or blackish.
Shell more or less rhomboid,
Somewhat ‘elongated, blackish. brimleyt.
Short, brownish. striatulum, modicellum, gibberum.
Generally ovate,
Rather thin, not inflated. patsaligense, simulans.
Rather solid, subinflated. bulbosum, ravenelianum,
hagleri, harperi, reclusum, nux, brumbyanum,
perovatum, pinkstom.
Elliptical, solid, much inflated.

Subsolid, black. strodeanum.
Solid, brown, rubellum, avellana, furvum.
Subtriangular.
Inflated, solid. curtum, showalteru.
Somewhat compressed, nacre purplish. lenticulare.
Nacre white. argenteum, fassinans.

Epidermis yellowish, tawny or light brown,
Rayless or feebly rayed.

Beaks terminal or subterminal. decisum,
chattanoogaense.

Beaks not terminal.
Oval or ellipttcal. hanleyanum, interventum, flav-
idulum, swordianum, litum, georgianum,
murrayanum.

Rhomboid.
Short. instructum, meredithii, breve, striatum.
Longer. argenteum, conasaugense, pyriforme,
amabile, estabrookianum.
Triangular. altum, instructum, troschelianum,

stabile, cor, verum, hartmanianum, crudum.

PLEUROBEMA 735

Generally raved,

Rays broken.
Compressed. planius, favosum.
Inflated. ornatum, acuens, cuneolus, appressum,
clinchense, Iesleyt.

Rays entire, or nearly so,

Compressed. bigbyanum, pudicum, oviforme.
Subinflated to inflated. validum, barnesianum.

Group of Pleurobema clava.

Shell solid, triangular; beaks high, generally anterior; beak
sculpture consisting of three or four broken, coarse, irregular
ridges; epidermis yellowish or tawny, marked with broken
green rays, which show a tendency to form square spots;
pseudocardinals often somewhat lengthened and more or less
parallel with the laterals.

Animal having the inner gills the larger except at the ex-
treme posterior end, free nearly or quite their whole length
from the abdominal sac; marsupium occupying the entire outer
gills; branchial opening rather large, with small papilla; anal
opening with minute papillee or crenulations. Animal dirty
whitish to salmon.

PLEUROBEMA CLAVA (Lamarck ).

Shell decidedly triangular, more or less inflated, solid ; beaks
excessively high, full, placed almost at or even in front-of the
anterior end, turned forward over a decided lunule that ex-
tends under and behind them, their sculpture consisting of a
few strong, irregular, often broken, ridges that turn up be-
hind ; anterior end generally truncate, often with a slope down-
ward and backward; sometimes the truncation is square, at
other times this end is evenly rounded and projects a little in
front of the beaks; base line nearly straight or somewhat
curved; dorsal line curved, the curve being sharper at or a
little behind ihe middle and meeting the base line at a point
on or a very little above the base; posterior ridge rather low,
but well defined, narrowly rounded, curved up in the middle,

736 PILEUROBEMA

running close to the dorsal line; near the ante-ior end there
is a wide, radial inflation extending from the beaks and fading
out below and the greatest diameter of the shell is at this in-
flation; growth lines rude and uneven; epidermis yellowish-
green, greenish-yellow, tawny, or brownish, usually more or
less decorated with bright green rays; the rays often coalesce
and are broken until they appear as square blotches, some-
times they are narrow and broken, smooth and shining to
rough and dull; pseudocardinals variable; there are generally
two in the left valve, the posterior stronger, often united above,
solid, rough, radial or the upper running nearly parallel with
the dorsal line; right valve with a strong pseudocardinal, there
is often one above it and another in front of it; laterals two
in the left valve and a double one in the right, heavy and gran-
lar; beak cavities shallow; muscle scars small, deep; nacre
silvery white, thicker in front.

Length 80, height 50, diam. 35 mm.

Length 87, height 47, diam. 37 min.

Length 58, height 39, diam. 33 mm.

Ohio, Cumberland, and Tennessee River systems, Maumee
Basin, Western New York, Ottawa, Canada (Call). Reported
from Iowa City, lowa; St. Peter’s River, Minnesota, and from
Nebraska.

Type locality, Lake Erie.

Unio clava LAMARCK, An. sans Vert., VI, 1819, p. 74.—Con-
RAD, Monog., I, 1835, p. 5, pl. 1, fig. 1—Kustrer, Conch.
Cab. Unio, 1852, p. 39, pl. vu, fig. 2—Sowersy, Conch.
Icon., XVI, 1868, pl. Lxrx, fig. 354.

Pleurobema clava Acassiz, Arch. fur Naturg., I, 1852, p. 49.—
SIMPSON, Syn., 1900, p. 745.—ORTMANN, Ann. Car. Mus.
VIII, 1912, p. 264. figs. 9-9a.

Unio clavus Reeve, Conch. Syst., I, 1841, p. 117, pl. LXXxXvIII,
fig. 3—Han ey, Biv. Shells, 1843, p. 187, pl. xx, fig. 52—
Cann, TreAcad Sci. Storms, Vil 18952 Wor te pso, pleu

Margarita (Unio) clavus Laas, Syn., 1836, p. 22; 1838, p. 18.

Margaron (Unio) clazus Lea, Syn., 1852, p. 26; 1870, p. 40.

PLEUROBEMA 737

? Unio patulus Lea, Tr. Am. Phil. Soc., III, 1829, p. 44. pl.
x11, fig. 20; Obs., I, 1834, p. 55, pl. xu, fig. 20.—Conrap,
Monog., X, 1838, p. 92, pl. L, fig. 2—HANLeEy, Biv. shells,
1843, p. 187, pl. xxu, fig. 27—CueENU, Ill. Conch., 1858, pl.
XVI, figs. 6, 6a, 6b.—Kuster, Conch. Cab. Unio, 1861, p.
250, pl. LXXxXvIl, fig. 5.

Margarita (Unio) patulus Lea, Syn., 1836, p. 22; 1838, p. 18.

Margaron (Unio) patulus Lea, Syn., 1852, p. 26; 1870, p. 40.

Unio cuneatus Say, Am. Conch., VI, 1834.

One of the most striking of North American Uniones. The
species is excessively variable in form and it is remarkable
that these variations have not oftener received specific names
at the hands of students. In some cases the very high beaks
project considerably ahead of any other part of the shell, the
anterior end below them being cut away with a strong, straight,
oblique truncation. At other times the beaks do not reach
quite to the anterior end, this end may be rounded or squarely
truncated; the truncation even slopes backward at the top i
some cases.. Specimens so shaped approach the form I have
taken for Unio maculatus of Conrad. There is a hitch of some
kind about Lea’s Unio patulus, which I cannot untangle. Dr.
Lea states that it came from T. G. Lea, from Ohio and he fig-
ures a shell that is shaped almost exactly like that of his U.
lesleyi, which is from Kentucky and Tennessee. J have never
seen stich a shell from Ohio and I am inclined to think that the
figure was made from a rather brightly rayed Jesleyi. All Lea’s
specimens marked patulus are quite different from the figure
and are evidently clava.

PLEUROBEMA MACULATUM (Conrad).

Shell subtrianguiar, compressed to subinflated, rather solid ;
beaks prominent and inflated, their sculpture apparently a few,
not very strong, irregular ridges; lunule small; anterior end
nearly evenly rounded, projecting a little in front of the beaks ;
base line nearly straight ; posterior and post-dorsal outline sub-
truncated, slightly curved, raised almost into a low angle near
the hinder end of the ligament: posterior ridge well developed,
suhangular above, narrowly rounded below, ending behind near

738 PI,EUROBEMA

the base in a blunt point ; surface nearly smooth in young shells
but having irregular, concentric growth in the old ones; epi-
dermis tawny-greenish to tawny-brown, beautifully marked
with narrow and wide interrupted dark green rays, scarcely
shining ; left valve with two moderate sized, somewhat stumpy
pseudocardinals and two curved laterals; right valve with two
pseudocardinals, the upper small and a double lateral; beak
cavities impressed; muscle scars very small and very deep;
nacre silvery white, brilliant, iridescent behind.

Length 65, height 50, diam. 30 mm.

Elk, Flint and Duck rivers, Tennessee.

Type locality, Elk and Flint rivers, Ala.

Unio maculatus Conrap, New F. W. Shells, 1834, p. 30, pl.
Iv, fig. 4.—CHENU, Bib. Conch., 1st ser., III, 1845, p. 17, pl.
I, fig. 7.—Kuster, Conch. Cab. Unio, 1861, p. 216, pl.
PAXIL ess 2

Margarita (Unio) maculatus Lea, Syn., 1836, p. 34; 1838, p.
22%

Margaron (Umo) maculatus Lea, Syn., 1852, p. 24; 1870, p.
38.

Pleurobema maculata SIMPSON, Syn., 1900, p. 747.

[ cannot be positive as to what Conrad’s species is as his
figure is rather poor. I have specimens before me from Duck
River, Tennessee, collected by Jas. H. Ferriss, that agree well
in form with Conrad's figure and description, but are a little
brighter and more distinctly painted with green than his figure
shows. Although specimens of clava somewhat approach this
in form and painting I consider the two perfectly distinct.
his shell is shorter, and the pseudocardinals are different,
being short and radial and not in any case parallel with the
dorsal line.

Dr. Lea is inclined to believe (Syn., 1870, p. 38), that Con-
rad’s Unio maculatus is the same as his own ravenelianus, and
if this were the case Lea’s name should have precedence. From
an examination of specimens in the Philadelphia Academy of
Natural Sciences and Conrad’s figure and description, I am
forced to differ from Dr. I,ea, as I consider the species close
to Lamarck’s clava.

PLEUROBEMA 739

PLEUROBEMA HOLSTONENSE (Lea).

Shell of moderate size, subtriangular, inflated, decidedly in-
equilateral, solid; beaks very high and full, sometimes in old
shells extending a very little in advance of the rest of the an-
terior end; anterior end either truncate or rounded; base line
somewhat rounded; dorsal and posterior outline curved, al-
most angular just at the hinder part of the ligament; lunule
small but well developed ; posterior ridge of moderate elevation,
narrowly rounded, ending behind in a blunt, rounded point
near the base of the shell; surface with irregular growth lines ;
epidermis yellowish, greenish-yellow or tawny, marked with
wide and narrow, interrupted rays; pseudocardinals rather
small, stumpy, subradial and rough, two in the left valve and
usually three in the right, the front and hinder one of the
right valve vestigial; laterals two in the left valve and a dou-
ble one in the right; beak cavities impressed; muscle scars
small, deep; nacre whitish.

Leneth 50, height 38, diam. 28 mm.

Length 52, height 37, diam. 29 mm.

Length so, height 35, diam. 25 mim.

Tennessee River system.

Type locality, Tuscumbia, Ala.

Umo holstonensis Lea, Pr. Am. Phil. Soc., I, 1840, p. 288;
ie aieel wile, SOs, Vil sto42 1p2202- pl. xy: fis 27°" Obs:,
IIT, 1842, p. 50, pl. xv, fig. 27—Cuenu, III. Conch., 1858.
pl. xxxu, figs. I, ta, 1b—Kuster, Conch. Cab. Unio, 1862,
Paco ple xGvin Hes A.

Margaron (Unio) holstonensis LEA, Syn., 1852, p. 25; 1870,
p. 38.

Pleurobema ho!stonensis SiMPSON, Syn., 1900, p. 746.

Unio mundus Ima, Pr. Ac. N. Sci. Phila., I, 1857, p. 83; Jl.
Ac. N. Sci. Phila., VI, 1866, p. 40, pl. xiv, fig. 38; Obs., XJ,
(867, p. 44, pl. xiv, fig. 38—Rerve, Conch. Icon., XVI,
1864, pl. xvt, fig. 72. ;

Margaron (Unio) mundus Lea, Syn., 1870, p. 40.

749 PLEUROBEMA

Unio law. Lea, Pr. Ac. N.eSct. Philagciy i879, 4.160; jl. Ane
N. Sei. Phila.: VII, 1874, 2p. 8) pl a ietc4 Obs er
1O7A,) Da.T2 pli. fie eA

Umo pattinoides Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 193;
Ji. Ac. N. Sei..:Phila., VW, 1874.69.16; soleing bee Once
XIII, 1874, p. 20, pl. rv, fig. 12.

Umno belluing Lea, Pr. Ac. No Sein Phila, 1) 1872.92 10% coe
Ac. N. ok. Phila.; VIM 1874) p250; ai xvi, fig. 48; Ore
XITI, 1874, p. 54, pl. xv, fig. 48.

I have united under one name a number of nominal species,
which, though they have some slight differences, do not seem
to me to be worthy of specific or even varietal rank. In gen-
eral this form is smaller than that, which I believe to be mac-
ulatum, it is more inflated and its base line is more rounded.
It is not so much lengthened as clava nor are its beaks placed
so far forward as a rule. The type of Unio holstonensis is.
quite a young, brightly rayed shell and very different from sev-
eral larger, rough, rayless specimens that Dr. Lea has placed
with it under that name, which I think, are his Unio pilaris.
The group typified by Unio clava is one of the most puzzling
in North America and I confess that in some cases I have not
been able to satisfactorily untangle its intricacies.

PI,EUROBEMA BOURNIANUM (Lea).

Shell triangular, short, subinflated or inflated, solid ; beaks.
very high, rather sharp, full, turned forward over a lunule,
placed nearest to the anterior end, their sculpture a few broken
ridges; anterior end somewhat obliquely truncated, posterior
outline curved from the beaks to the base; base line curved in
front, nearly straight behind; posterior ridge low, narrowly
rounded, placed almost at the posterior outline, ending below
in a point at the base of the shell; in front of the middle of
the shell there is a wide, high, radial swelling and here the
diameter is much the greatest ; between this and the posterior
ridge there is a wide radial depression; surface with irregular
growth lines; epidermis greenish-yellow or pale tawny, with
conspicuous, narrow and wide, interrupted green rays, sub-

P1,EUROBEMA 741

shining ; pseudocardinals low, irregular, rough, two in the left

valve and three in the right; laterals curved, left valve with

two, right valve with a double one; beak cavities shallow,
muscle scars small, deep; nacre white.

Length 30, height 32, diam. 19 mm.

Length 38, height 40, diam. 26 mm.

Type locality, Scioto River, near Chillicothe, Ohio.

Unio bournianus Lea, Pr. Am. Phil. Sci., I, 1840, p. 288; Tr.
Avex Phils soc. IV LEL Mr S42. p. 213) pl xv, he: 23: ‘Obs., IT,
p- 51, pl. xv, fig. 28.—CHENU, Ill. Conch., 1858, pl. xxvii,
figs. 2, 2a, 2b.

Margaron (Unio) bournianus Lea, Syn., 1852, p. 25; 1870,
P. 30.

Pleurobema bournianus SIMPSON, Syn., 1900, p. 747.

Lea has three shells, to which he gives this name. The
larger one is considerably deformed, and the medium one, the
type, is probably not exactly normal. I am doubtful whether
the third, a young shell, is the same as the others. The species
is close to edgarianum and may possibly be merely a slight
malformation of that. It is higher than long and the beaks.
are more pointed than they are in that species.

PLEUROBEMA EDGARIANUM (Lea).

Shell subtriangular, subinflated to inflated, solid, inequilat-
eral: beaks full and high, turned forward a little over a lunule ;
their sculpture a few strong, broken, subnodulous ridges; an-
terior end obliquely truncated above, rounded below ; posterior
end curved from the beaks to the base, often subangular just
behind the ligament; base line nearly straight behind, curved
up in front; posterior ridge well developed, curved so that it
runs nearly parallel with the posterior outline, but placed some
distance in front of it, narrowly rounded or angular, some-
times slightly double below, ending in a point or biangulation
at the base line: in front of the middle there is a wide radial
swelling and here the diameter of the shell is greatest ; surface
with uneven growth lines; epidermis greenish-yellow, yellow-
green or brownish, in young shells generally having wide and

742 PLEUROBEMA

narrow broken rays, and shining, often dull and feebly raye.,
in old shells; pseudocardinals irregular, rough, two in the left
valve and three in the right, the anterior and posterior teeth
in the right feeble; two laterals in the left valve and a some-
what double one in the right; beak cavities compressed, deep
for a Pleurobema; nacre white; muscle scars deep, small.

Length 45, height 45, diam. 35 mm.

Length 53, height 48, diam. 31 mm.

length 45, height 40, diam. 3: mm.

‘ennessee River system.

Type locality, Holston River, Tenn., and Tennessee River,
Florence, Ala.

Unio edgarianus Lea, Pr. Am. Phil. Soc., I, 1840, p. 288; Tr.
Am. Phil: Soc, Vil 1842" p. 214. pl axe noe 0 -e@)ns. mien
1842, p. 52, pl. xv, fig. 30.—CueENu, Ill. Conch., 1858, pl.
XXIX, figs. 5, 5¢, 5b>—Kustrr, Conch. Cab., 1861, p. 213,
pl. Lxx, fig. 5——Muscrave, Phot. Conch., 1863, pl. 11, fig. 6.
—Rerve, Conch. Icon., XVI, 1864, pl. xv, fig. 65.

Margaron (Unio) edgarianus Lea, Svn., 1852, p. 25; 1870, p.
39.

Pleurobema edgarianus SIMPSON, Syn., 1900, p. 747.

Unio obuncus Lea, Pr. Ac..N: Se, Phila., 1, 1871, ‘p. 1925 Ji:
Ac: Nw Ser Phila: Vill, 1874p. 9;.pl ais fears Oss axe
1874, Pe 13s split, fies <5.

Unio andersonensis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p.
rs; jl Ac. N. Sew Phila., VIL 1874, p..30,.ple in ie 3 4,
Obs:, <I, 18745 p. 40; plo; fe. 32.

The specimens placed by Dr. Lea under Unio edgarianus
show a wide degree of variation in form and color. I have
placed in the synonymy his Unio obuncus and andersonensis,
which differ less from edgarianus than specimens of that spe-
cies do among themselves. The young shells are mostly bright
and rayed, they usually become dull and feebly rayed when
old and at this stage they may be brown or tawny colored.
The beaks are fuller and less sharply elevated than in bourni-
anum, the beak cavities are deeper, in fact they are unusually
deep for a Pleuwrobema; the posterior ridge is not so low nor
is it placed so near the posterior line as it is in bournianum.

PLEUROBEMA 74

o>)

PLEUROBEMA CUNEOLUS (Lea).

Shell subtriangular or subrhomboid, convex to subinflated,
inequilateral, solid; beaks high, moderately full; anterior end
usually obliquely truncated above, rounded below, sometimes
rounded throughout; basal line nearly straight; post-dorsal
line curved, rising in the middle almost or quite to an angle;
posterior ridge subangular, ending below in a point at the base,
not so high as the radial swelling in front of it; epidermis
greenish-yellow or yellow-green, with wide or narrow, broken
rays, rather dull; pseudocardinals rough and uneven, double
in each valve, laterals curved, that of the right valve partly
double; muscle scars small, impressed; nacre white.

Length 50, height 38, diam. 23 nim.

Length 45, height 36, diam. 19 mm.

Tennessee River system.

Type locality, Holston River, Tenn.

Unio cumeolis Vex, Pr Am. Phil.-Soc., 1, 1840, p. 286% Tr.
Aime Eiko soc, Vill. 1842p) 163) pl. vil, fig. 3: Obs:, 1,
$842, p. 31, pl. vi, fig. 3—Cuenu, Ill. Conch., 1858, pl. xxx,
figs. 2, 2a, 2b.—Kuster, Conch. Cab. Unio, 1861, p. 182, pl.
LXvu, fig. 4—Rreve, Conch. Icon., XVI, 1865, pl. xxir,
fee TO?

Margaron (Unio) cuneolus Lea, Syn., 1852, p. 24; 1870, p. 38.

Pleurobema cuneolus SIMPSON, Syn., 1900, p. 748.

\ rather compressed species when compared with those that
precede it. The post-dorsal line is quite high behind the liga-
ment, so that the shell becomes in some cases subrhomboid.
The beak cavities are not so deep as those of edgarianum, the
muscle scars are comparatively shallow. I cannot separate
Jjea’s Unio cuneolus and clinchensis by any characters of
value.

PI,EUROBEMA CLINCHENSE (Lea).

Shell subtriangular, inequilateral, scarcely inflated, solid;
beaks high but not very full; anterior end rounded; base near-
ly straight: post-dorsal line curved, elevated into a low angle
medially ; posterior ridge rounded, ending near the posterior

744 PILEUROBEMA

base of the shell; surface with irregular growth lines, greenish-
yellow with two or more broken, narrow or wide rays; pseudo-
cardinals solid, radial, two in the left valve and three in the
right; left valve with two laterals, that of the right partly
double; muscle scars small, impressed; beak cavities shallow ;
nacre whitish or straw-color, thinner and iridescent behind.

Length 45, height 36, diam. 20 mm.

Clinch River, Tennessee.

Type locality, Clinch, French Broad and Holston Rivers,
Tenn.

Umio clinchensis Lea, Pr. Ac. N. Sci. Phila., XI, 1867, p. 81;
Ji Ac. N.-Sei” Phila.” V1, 1868: 9.2276, pl. xxvii hie a Or
Obs.; XIT, 1860;-p. 28) pl. xx xvi, fis. OL:

Margaron (Unio) clinchensis Lea, Syn., 1870, p. 38.

Pleurobema cuneolus (part), SIMPSON, Syn., 1900, p. 748.

{n the Synopsis I placed this species in the synonymy of
Unio cuneolus Lea. lLea’s figured type of the latter is a
young shell and is more rhomboid and is straighter on the base
than is the type of his clinchensis. In his collection there is a
large shell from the Clinch River, which he has labeled Unio
cuneolus, which approaches his clinchensis so closely that I am
not sure which species it should be referred to. In general
cuneolus is a little more rhomboid than clinchensis and has a
straighter base line, it being sometimes slightly incurved, while
that of clinchensts is very faintly curved.

PLEUROBEMA LESLEYI (Lea).

Shell somewhat drawn out, subtriangular, subrhomboid or
. nearly evenly ovate, inequilaterai, subsolid to moderately solid,
subcompressed to scarcely subinflated; anterior end rounded
or very slightly subtruncate above; base line lightly curved to
straight: post-dorsal line curved, often elevated nearly to an
angle in the middle; beaks only moderately high, not very full;
surface with rather rude growth lines; epidermis dull green-
ish, tawny or yellowish, with a few broken, green rays, not
shining ; pseudocardinals two in the left valve and one in the
right, with occasionally vestigial teeth in the right valve; lat-

PLEUROBEMA 745

erals two in the left valve and a somewhat double one in the
right; beak cavities not deep; muscle scars well impressed ;
nacre white, thicker in front.

Length 61, height 40, diam. 24 mm.

Length 58, height 35, diam. 18 mm.

Type locality, Kentucky ; Tennessee.
imo tesievi Lea, Pr. Ac. N. Sci. Phila., 1V,. 1860, p. 306; Jl.

AcwN. oc rila;, TVe tooo, p:.352, pl. tvit, fig. 17753 Obs.,

VTL, 1860, p: 34, pl.Lvint, fig: 177.

Margaron (Unio) lesleyi Lea, Syn., 1870, p. 40.
Pleurobema les!eyi StIMPSON, Syn., 1900, p. 748.

Approaches cuneolus, but is more elongated, rather more
nearly elliptical and has perhaps more regular pseudocardinals.
I have heretofore remarked that the figure of Unio patulus
seems nearer to this than anything else.

PLEUROBEMA OVIFORME (Conrad).

Shell irregularly ovate or subrhomboid, scarcely subinflated,
rather solid; beaks high, not very full, turned forward over a
well-developed lunule, their sculpture a number of broken, sub-
nodulous ridges: posterior ridge moderate, narrowly rounded,
ending just below the median line in a point; outline of the
dorsal slope curved, much elevated and subangular near the
middle; base line rounded; anterior end rounded; epidermis
with fine, concentric folds, nearly smooth on the earlier growth,
tawny, greenish-yellow or yellow-green, with narrow and
broad broken rays; pseudocardinals uneven, two in the left
valve, one with vestiges of two others in the right; laterals
two in the left valve, a double one in the right; beak cavities
rather shallow ; muscle scars deep, small; nacre silvery-white.

Length 46, height 33, diam. 20 mm.

Type locality, Tennessee.

Unio oviformts Conrap, New F. W. Shells, 1834, p. 46, pl. 1,
fig. 6.—CHENu, Bib. Conch., tst ser., III, 1845, p. 22, pl.
a. Ss 7.

Margaron (Unie) oviformis Lra, Syn., 1852, p. 26; 1870, p. 40

Pleurobema oviformis Simpson, Syn., 1900, p. 748.

746 PLEUROREMA

“, beautiful species, which is more brightly painted than
cuneolus, and is more compressed behind laterally than that
shell. It is brighter and less elongated than P. lesleyi.

PLEUROBEMA ACUENS (lLea).

Shell irregularly ovate or subrhomboid, subinflated, solid,
inequilateral; beaks high and full, with a lunule in front of
them ; anterior end rounded or very slightly subtruncate above ;
base line evenly curved: outline of dorsal slope curved, high
and almost angled behind the ligament; posterior ridge round-
ed, ending behind above the base of the shell in a rounded
point ; surface with uneven growth lines ; epidermis pale tawny,
with a few broken, green rays, scarcely shining; pseudocardi-
nals small, triangular, two in the left valve and one in the
right ; two laterals in the left valve and a double one in the
right; beak cavities shallow; muscle scars small, deep; nacre
beautiful silvery, richly iridescent and thinner behind.

Length 33, height 25, diam. 16 mm.

Tennessee River system.

Type locality, Holston River, Concord, Tenn.

Unio acuens Wek, Pr-Ac. Nat; Sci. Phila.” 1871. p: 19o0seyL-
Ae. Nata semjbhila. VI 1874 sp.27,.pl. vin, te 24 Oras
XT, 1674. si pl Winn, no eae

Pleurobema acuens SIMPSON, Syn., 1900, p. 479.

Apparently this is a rare shell and all the specimens I have
seen are small, though they have the appearance of being adult.
It is a neat species, the posterior ridge being widely rounded,
the greatest degree of inflation being above it. The nacre is
beautifully soft and rich, and it has the faintest hint of red.
The hinder part is richly iridescent and almost coppery and it
is much thinner than the rest of it.

PLEUROBEMA ORNATUM (Lea).

Shell subrhomboid, subcompressed, solid, inequilateral ;
beaks high, only moderately full, their sculpture apparently a
few coarse ridges; lunule small; posterior ridge rounded, end-
ing behind in a rounded point near the base of the shell; base

P1LEUROBEMA 747

line slightly curved; anterior end rounded; outline of the dor-
sal slope curved, raised almost to an angle in the middle; sur-
face nearly smooth; epidermis greenish-tawny with a few con-
spicuous, widely interrupted rays, the whole rather bright:
left valve with two ragged pseudocardinals, the anterior small,
and two nearly straight laterals; right valve with three pseudo-
cardinals, the median one large, the others small, and a slightly
double lateral; muscle scars small, impressed; beak cavities
shallow, compressed; nacre silvery, thick in front, thin, cop-
pery, iridescent and almost transparent behind.

Length 27, height 22, diam. 12 mm.

Type localitv, Alabama.

Umo ornatus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 4; Jl. Ac.
Ne pei winnila.. Vi. 1S02.\p. O5, plexity fic! 2394; Obs; VITT,
1862, p. 80, pl. x1, fig. 234.

Margaron (Unio) ornatus LA, Syn., 1870, p. 57.

Pleurobema ornata SIMPSON, Syn., 1900, p. 749.

I have no doubt that the only specimen I have seen of this.
the type, is a young shell, though Dr. Lea believed it to be
nearly adult. It is one of those puzzling forms, which have
no very decided characters, yet do not seem to belong to any
other species. It is more rhomboid than oviforme, not so
much drawn out behind to a point. It is much less inflated
than tesserule, is smaller and less triangular than bigbyense,
to which Dr. I,ea compares it.

PIEUROBEMA APPRESSUM (T[,ea).

Shell subrhomboid, very inequilateral, the beaks being placed
almost at the extreme anterior end, solid, subcompressed or
scarcely inflated, with a well-developed, rounded, curved pos-
terior ridge. In front of this ridge the shell is somewhat flat-
tended, the compressed area extending to a sort of rounded,
radiating, wide ridge near the anterior end; beaks high, full,
turned forward over a well-developed lunule, their sculpture
not observed: surface with irregular growth lines; epidermis
somewhat wrinkled, greenish-yellow in the young state, dark
tawny-brown in the adult shell, with faint indications of broken

748 PILEUROBEMA

rays; left valve with two strong pseudocardinals, which are
slightly roughened, the posterior slightly divided, with two
curved laterals, the lower the stronger; right valve with one
strong pseudocardinal, with a vestigial one in front of it and
sometimes one or more imperfect denticles behind it and one
lateral ; hinge plate wide and flat ; cavity of the beaks not deep,
but compressed; muscle scars small, impressed; pallial line
crossed by. short radiating ridges; nac:e dirty or lurid white,
blotched in the type.

Length 60, height 47, diam. (near anterior end) 28, near
posterior end 24 mm.

Clinch and Holston rivers.

Type locality, Tuscumbia, Ala.; Tennessee River and Hols-
ton River, Tenn.

Unio appressus Lea, Pr. Ac. N. Sei. Phila. Ij, 1871; pa 169;
jl. Ac. Ny Sei: Philaz, VILEA1874; py pe a hes aban
XIII, 1874, pl. 11, fig. 8.

Pleurobema appressa SIMPSON, Syn., 1900, p. 749.

Unio argenteus SowrERBY, Conch. Icon., XVI, 1866, pl. xxxvit,
fig. 204.

This species is dangerously near two or three others. The
fact is an almost unbroken chain seems to exist connecting this
with Unio tuscumbiensis, favidus, tumescens, radiosus, dolla-
helloides, thorntonii, mooresianus, recurvatus, circumactus and
some other forms. Most specimens of appressum are a little
more compressed than most of these and are tawny-brown
and rayless, though the type is rayed and more inflated than
the average. I confess that with the types of all these so-
called species and an abundance of other material, 1 am unable
to make any arrangement that is satisfactory.

PLEUROBEMA TUSCUMBIENSE (Lea).

Shell subtriangular or subrhomboid, subinflated to inflated,
solid, inequilateral: beaks high, full, long, their sculpture ap-
parently a few broken, nodulous ridges ; lunule well developed ;
anterior end somewhat obliquely truncate above, rounded be-
low; base line curved or straight; outline of the dorsal slope
curved, elevated almost to an angle behind the ligament; pos-

PLEUROBEMA 749

terior ridge well defined, narrowly rounded, curved, it is not
so high as the wide radial swelling near the anterior end;
between the two the surface is flattened ; surface with irregular
growth lines; epidermis greenish-yellow to tawny, usually
marked with narrow and wide, broken, green rays; pseudo-
cardinals irregular, ragged, left valve with two, right valve
with three, the lateral ones small; laterals two in the left
valve and a double one in the right ; beak cavities shallow, com-
pressed; muscle scars deep, small; nacre bluish to yellowish-
white.

Length 38, height 34, diam. 22 mm.

Length 43, height 37, diam. 24 mm.

Tennessee River system.

Type locality, Tuscumbia, Ala.; Holston River, Tenn.

Unio tuscumbiensis Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 191;
(inc. No Sci, Pinta VILL 13874, p, 11, pli, Ag.7; Obs.,
Pee Logs. 5. Pl. Ao. 7

Umio flavidus’ Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 156; J).
Dew apcmrnia Vill 1a74, p. 28, pl 1x, fie. 2s5;--Obs.,
Mel aS74.-p. 32> pl. 1X, fig..25,

Pleurobema appressa (part), SIMPSON, Syn., 1900, p. 749.
Although there are specimens, which may be about as easily

referred to P. appressum as to this, it may be best to separate

the two. Generally this form seems to be smaller than ap-
pressum, a little more inequilateral, and a little more inflated.

Lea's Unio flavidus seems to me to be absolutely identical with

his tuscumbiensis.

PLEUROBEMA TESSERULA (Lea).

Shell small, much inflated, subrhomboid, solid, inequilateral ;
beaks high, full, but not much elongated, their sculpture ap-
parently a few coarse ridges, which curve up behind; lunule
small; anterior end narrowly rounded and gaping; base line
nearly straight; dorsal line behind the beaks straight, meeting
the oblique truncation of the dorsal slope at an angle ; posterior
ridge full, narrowly rounded, ending behind in a rounded point
at the base of the shell; surface finely but unevenly, concentri-
cally striate; epidermis yellowish-green, marked with a few

750 PILEUROBEMA

green rays that break up into squarish blotches, scarcely shin-

ing ; pseudocardinals small, stumpy, two in the left valve, three

in the right; laterals two in the left valve and a somewhat
double one in the right; beak cavities shallow; muscle scars
small, deep; nacre bluish-white, thin and iridescent behind.

Length 28, height 21, diam. 18 mm.

Type locality, Nolachucky River, ‘l’ennessee.

Umno tesserule les, Pr Aci Ne Scr Phila, Vie 186i, page
Ji, Ac: IN. Set. Phila., VI, 1866, "p: 40,-pl: xy, fig: 39+) Obs:
XI, 186075 p. 44, pl xvotie) 30.

Margaron (Unio) tesserule Lea, Syn., 1870, p. 36.

Pleurobema tesserule Simpson, Syn., 1900, p. 749.

A well-characterized little species, which seems to be quite
rare, as | have only seen two or three authentic specimens. It
is much inflated, is decidedly rhomboid; it gapes rather widely
at the anterior base and the hinder part of the nacre is thin,
and iridescent, almost translucent and has a purplish tint. It
seems to be a healthy, normal species.

PLEUROBEMA VALIDUM (Lea).

Shell subtriangular, scarcely inflated, solid, inequilateral ;
beaks high, rather full; lunule narrow; anterior end very
slightly, obliquely truncated above, widely rounded below
base line curved; outline of the dorsal slope curved, raised al-
most to an angle at the hinder part of the ligament; posterior
ridge narrowly rounded, straight, ending below in a blunt
point near the base of the shell; surface with uneven, concen-
tric sculpture ; epidermis tawny-greenish, with numerous, rath-
er faint, scarcely broken rays; pseudocardinals rough, radial,
two in the left valve and three in the right, the middle
one in the right valve strong; left valve with two laterals;
right valve with a somewhat double one; beak cavities shallow ;
muscle scars small, deep; nacre silvery, slightly iridescent be-
hind, thicker in front.

Length 55, height 45, diam. 26 mm.

‘Tennessee.

Type locality, Duck River, Tenn.

PLEUROBEMA Heyl

Unio validus Ia, Pr. Ac. N. Sci. Phila., I, 1871, p. 189; Jl. Ac.
N. Sci. Phila., VIII, 1874, p. 6, pl. 1, fig. 2; Obs., XIII, 1874,
pL kO; pli, fig. -2.

Pleurobema valida Simvson, Syn., 1900, p. 749.

This shell is more distinctly triangular than its allies; the
rays are rather narrow on the only examples I have seen, and
are scarcely broken.

PLEUROBEMA TUMESCENS (Lea).

Shell nearly triangular, inflated, solid, inequilateral; beaks
long, very high and full; lunule large; anterior end decidedly,
obliquely truncated above, rounded below; base line nearly
straight ; outline of the dorsal slope slightly curved; posterior
ridge well developed, rounded, the shell being only a little
fuller in front of it; surface with uneven growth lines; epider-
mis greenish-yellow to tawny, faintly rayed; pseudocardinals
irregular, two in the left valve and three in the right; laterals
curved, two in the left valve and a double in the right ; beak
cavities shallow; muscle scars small, moderately deep; nacre
white or yellowish.

Length 43, height 40, diam. 27 mm.

Tennessee. The localities, Alexandria, Louisiana, of Lea,
of the type, and Ouachita River, given by Call, are open to
doubt.

Unio tumescens La, Pr. Am. Phil. Soc.. IV, 1845, p. 164; Tr.
Am: Phil: Soc, Xx, 1848, p. 71, pl: m1 fie.-7 ; Obs.; 1V, 1848,
(Fe At my 8) un cr a Keane

Margaron (Unic) tumescens Lea, Syn., 1852, p. 25; 1870, p.
38.

Pleurobema tumescens SIMPSON, Syn., 1900, p. 750.

Umo radiosus lea, Pr. Ac N. Ser. Phila. 1, 1871, p. 192; Jl.
Ac, Necocterhila,, Villy s137421p) <3; pli 1m, figs -93-/Obs.,
ML 18745 /p. a7 plyan, figso.

Close to dolabelloides but more strictly triangular and small-
er. The beaks are not quite so high nor so much curved for-
ward as in that species. I cannot see that radiosus differs in
any character from tumescens.

752 PLEUROBEMA

PLwZUROBEMA DOLABELLOIDES (Lea).

Shell subtriangular, inflated, very solid, with high, full beaks,
which with the umbonal region curve forward, and are placed
near the anterior end, inequilateral; anterior end obliquely
truncate above, rounded into the base below; base curved;
outline of the dorsal slope strongly curved; posterior ridge
narrowly rounded, not elevated so much as the radial swell-
ing in front of it, strongly curved throughout; surface irregu-
larly concentrically sculptured; epidermis tawny to brownish
with a few broken rays; pseudocardinals uneven, two in the
left valve and three in the right; laterals curved, two in the
left valve and a double one in the right ; beak cavities shallow,
compressed; muscle scars small, deep; nacre white, straw-color
or somewhat lurid.

Length 51, height 55, diam. 36 mm.

Length 48, height 52, diam. 32 mm.

Tennessee River drainage.

Type locality, Holston River, Tenn.

Unio dolabelloides Lea, Pr. Am. Phil. Soc., I, 1840, p. 288;
Tr. Am. Phil. Soe. VIEL, 1842, py 215, pix, fie er eS @hse,
III, 1842, p. 53, pl. xv, fig. 31—CueEnu, Ill. Conch., 1858,
pl. xxix, figs. 4, 4a, 4b.—Kusrer, Conch. Cab., 1861, p. 214,
pl. .xxi, fig. 3—Sowesry, Conch. Icon., XVI, 1866, pl.
XXXVI, fig. 205.

Margaron (Unio) dolabelloides Lua, Syn., 1852, p. 35; 1870,
p. 50.

Pleurobema dolabelloides StMPSON, Syn., 1900, p. 750.

Unio thornton Lea, Pr. Ac. N. Sei. Phila., I, 1857, p. 83; Jl.
Ac. N.- Sei: Phila., V1, 1866, pi38; pl. xiv, fies 36.7 Obss OG
1867, p. 42, pl. xiv, fig. 36.

Margaron (Unio) thornton Lea, Syn., 1870, p. 56.

Unio mooresianus Tea, Pr. Ac. N. Sci. Phila., I, 1857, p. 83;
Jl. Ac. N. Sci. Phila., VI, 1866, p. 39, pl. xiv, fig. 37; Obs.,
Xi2.1867,-p. 42; pl xiv, fetes

Margaron (Unio) mooresianus LEA, Syn., 1870, p. 39.

Unio moorenianus Pret, Conch. Sam., IIT, 1890, p. 159.

x PLEUROREMA 753

Unio recurvatus Lua, Pr. Ac. N. Sci. Phila., I, 1871, p. 192;
jiexcoN. Set Phila. VIL, 1874; p. 10,, pl. 11, fig. 6; Obs.,
XIE, 1874, p- 14, pl: 11, fig. 6.

Umo cireumactus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 192;
jienc IN. sci. Phila, Vill, 1874, plk.av, fig: 11; Obs., XIII,
taza. p. LOs piv, fis. Li.

Unio subglobatus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 191;
ie Nese cis baila.” VIL 1874.4... 7; «pls 1, fig:.3; Obs.
Rell 1874, 'p: ar, pl: he: 3.

Pleurobema subglebata Simpson, Syn., 1900, p. 751.

I have united under the oldest name a number of nominal
species, some of which seem to be slightly identical and others
are apparently the merest variations. I placed Unio subglob-
atus by itself as a species in the Synopsis and it has slightly
higher beaks than the average dolabelloides. But there is a
complete connection through thorntonii to dolabelloides and to
circumactus, which has slightly lower beaks and is a little
less inflated than the rest.

PLEUROBEMA CRUDUM (Lea).

Shell subtriangular, subinflated. solid, inequilateral, with full
high beaks; posterior ridge well developed, rounded, curved ;
anterior end rounded or very slightly, obliquely truncated
above; base line nearly straight; post-dorsal outline evenly
curved from the beaks to the rounded posterior point near the
base of the shell; surface with irregular growth lines; epider-
mis cloth-like, brownish or greenish-brown, nearly rayless;
hinge plate wide; pseudocardinals irregular, torn, two in the
left valve and three in the right; laterals two in the left valve
and a double one in the right; beak cavities shallow ; muscle
scars very small, deep; nacre white, thicker in front.

Length 46, height 39, diam. 22 mm.

‘Type locality, French Broad, and Holston rivers, Tennessee ;
Swamp Creek, Murray County, Georgia. Also Cumberland
River, Tenn.

Unio crudus Les, Pr. Ac. N. Sci. Phila., I, 1871, p. 190; Jl.
Boon. Seto Phila. Villy 1674.apens, pl. iv, fig, 10; Obs.,
XIII, 1874, p. 18, pl. rv, fig. -1o.

Pleurobema cruda StMPpson, Syn., 1900, p. 757.

754 PLEUROBEMA

Something like P. appressum, but not so compressed on the
disk. It seems close to dolabelloides, but the beaks are hardly
so high and the color and texture of the epidermis differs a
little from that of either of them. I have only seen one shell
that I am sure is valid, the type. Another that Dr. Lea has
placed with that 1s his Unio pudicus, I think.

PLEUROBEMA BARNESIANUM (Lea).

Shell nearly elliptical, rather solid, convex or subinflated,
inequilateral; beaks rather high and full; posterior ridge
strong, subangular or narrowly rounded, ending below the
median line in a point; anterior end nearly evenly rounded;
base line curved; dorsal line lightly curved, meeting the outline
of the subtruncated dorsal slope at an angle; surface with
fine, uneven growth lines; epidermis tawny to dirty greenish-
brown, faintly rayed, subshining ; pseudocardinals small, radial,
two in the left valve and three in the right; laterals two in the
left valve and a somewhat double one in the right; beak cavi-
ties shallow ; muscle scars smail, impressed ; nacre white, tinted
purple.

Length 44, height 34, diam. 20 mm.

Length 37, height 27, diam. 15 mm.

Cumberland and Tennessee River systems.

Type locality, Cumberland River, Tenn.

Unio barnesianus Lea, Tr. Am. Phil. Soc., V1,.1838, p. 31, pl.
x, fig. 26; Obs., II, 1838, p. 31, pl. x, fig. 26—HANLEy, Biv.
Shells, 1843, p. 185, pl. xxtu, fig. 14.—Cuenu, Ill. Conch.,
1858, pl. xrx, figs. 2, 2a, 2b>—Sowersy, Conch. Icon., XVI,
1866, pl. XxxIV, fig. 180.

Vargarita (Unio) barnesianus LEA, Syn., 1836, p. 20; 1838, p.
Ge

Margaren (Unio) barnesianus LEA, Syn., 1852, p. 24; 1870, p.
38.

Pleurobema barnesiana SIMPSON, Syn., 1900, p. 751.

Unio ravenelianus Rerve, Conch. Icon., XVI, 1864, pl. xvt,
fig. 70.

Unio tellicoensis Lua, Pr. Ac. N. Sci. Phila., II, 1872, p. 155;
Jl. Ac. N.. Scis Phila, VINE 1874; (p: 31) ph xyes 26-7Obs.
XL, 1874, peesepl- x, exec:

PLEUROBEMA TOD

I have given first the measurements of the type of Lea’s
Unio tellicoensis and then those of his barnesianus. The latter
is a younger shell and naturally not quite so inflated as the
older one. I can see no other difference worthy of mention
between the two. The form is quite elliptical for a Plewrobema
of this group, but it has the characteristic texture and epider-
mis and | believe that it should be placed there.

PLEUROBEMA PUDICUM (Lea).

Shell subrhomboid or subelliptical, subinflated, inequilateral,
rather solid; beaks full and high; posterior ridge strong, nar-
rowly rounded, sometimes feebly and narrowly biangulate
below, ending in a slight biangulation near the base of the
shell: anterior end nearly evenly rounded; base line curved ;
post-dorsal outline curved, raised in the middle almost to an
angle; surface with fine, uneven growth lines; epidermis yel-
lowish-green to tawny-brown, more or less rayed, scarcely
shining ; pseudocardinals small, uneven, rough, two in the left
valve and three in the right; laterals curved, two in the left
valve and a double one in the right; beak cavities not deep;
muscle scars small, impressed; nacre silvery, white tinted pur-
ple.

Tennessee River system.

Type locality, Florence and Northern Alabama.

Unio pudicus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 92; Jl.
Neen: Scuebhila., kV, 1660, po 346, pl tv1, fig. 171;-Obs.,
VIII, 1860, p. 28, pl. tvt, fig. 171—Sowerrsy, Conch. Icon.,
NVI, 1668 pl rxXxxt, fig. 427.

Margaron (Unio) pudicus Lea, Syn., 1870, p. 37.

Pleurobema pudica SIMPSON, Syn., I900, p. 751.

Unio subrotundus Sowerby, Conch. Icon., XVI, 1866, pl.
XVil, He. 2OD.

Unio lyonii Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 89; Jl. Ac.
N. Sci. Phila., VI, 1869, p. 259, xxxu, fig. 74; Obs., XII,
(O00; pidO, pl xxx, fie. 74.

Margaron (Unio) lyonii Lea, Syn., 1870, p. 56.

Pleurebema lyonii StMrson, Syn., 1900, p. 751-

756 PLEUROBEMA

The type of Unio pudicus is a young shell and is brighter
and more compressed than that of Unio lyonit, which is an
adult shell. Since writing the Synopsis I have had an oppor-
tunity of examining a number of shells of the U. pudicus and
it seems to me to he identical with lyonii. The form is less
triangular than bigbyense and a little more inflated.
PLEUROBEMA BIGBYENSE (Lea).

Shell subcompressed, subtriangular or subrhomboid, inequi-
lateral, subsolid; beaks high and moderately full, their sculp-
ture a few strong, uneven, subnodulous ridges that curve up
behind; anterior end rounded ; base line lightly curved; outline
of the dorsal slope curved, raised to an angle behind the liga-
ment; posterior ridge rounded or imperfectly double, ending
in a blunt point near the base of the shell; surface nearly
smooth ; epidermis greenish-yellow with numerous green, en-
tire or broken rays, sometimes with broken bands of green;
the whole bright and glossy; pseudocardinals radial, two in
the left valve and three in the right; laterals two in the left
valve and a somewhat double one in the right; muscle scars
rather small, impressed: beak cavities shallow; nacre white.

Length 52, height 39, diam. 18 mm.

Tennessee River drainage; Indian Territory? Texas? The
two last localities very doubtful.

Type locality, Big Bigby Creek, Maury Co., Tenn.
Umolbigbyensis Lea,-Pr Am. Phil, Soe, Hy as4i.ep. 305ehi

Am, Phil.-Soc., VILL 1843, p; 237,.pl: sox, hie BOs

ITT, 1842, p. 75, pl. xxu, fig. 51.—CuHeENu, Ill. Conch., 1858,

pl. xxu, figs. 5, 5a, 5b.—Kuster, Conch. Cab. Unio, 1862, p.

270, pl. xciv, fig. 3—Sowersy, Conch. Icon., XVI, 1866, pl.

ST Aey 2277.

Margaron (Unio) bigbyensis Lea, Syn., 1852, p. 24; 1870, p.

38.

Pleurobema bigbyensis Simpson, Syn., 1900, p. 75T.

This species seems allied by its form to the argenteum
group, but the coler pattern is that of the clava group. Its
form is much like that of P. argenteum, but that species 1s
dull and rarely exhibits even traces of rays.

PLEUROBEMA

be
in
“J

Group of Pleurobema swordianum.

Shell oval, convex; beaks only moderately elevated, epider-
mis nearly or quite ravless; teeth strong; laterals reaching well
forward; muscle scars large, deep; nacre lurid.

PLEUROBEMA SWORDIANUM (S. H. Wright).

Shell large, irregularly ovate, not inflated, quite inequilat-
eral; beaks moderately elevated and full, placed well forward;
lunule narrow ; ligament long; posterior ridge widely rounded:
outline of dorsal slope almost evenly curved; posterior end
rounded ; base line slightly curved; anterior end rounded ; sur-
face widely, concentrically striate; epidermis tawny-brownish,
nearly or quite ravless; left valve with two strong, rough,
radial pseudocardinals and two strong, curved laterals; right
valve with three radial pseudocardinals and a somewhat double
lateral; laterals reaching forward to the pseudocardinals ;
beak cavities shallow; muscle scars latge, deep; pallial line
crenate, remote from the border; nacre lurid, greenish-vellow.

Length 95, height 71, diam. 38 mm.

Type locality, Powell’s Creek, Lee Co., Va.

Unio swordianus 5. H. Wricut, Naut., XI., 1897, p. 4.
Pleurobema swordiana Simpson, Pr. Ac. N. Sci. Phila., 1900,

p. 81, pl. iv, fig. 4; Syn., 1900, p. 750.

A peculiar and puzzling form, which has characters of sev-
eral groups. It has something of the form of Quadrula kirt-
landiana, and it resembles O. bursa-pastoris, but it has shallow
beak cavities. It has some of the characters of P. appressiwm,
but is larger, has large muscle scars, remote pallial line, and
it has remarkably elongated laterals, which reach forward to
near the front part of the pseudocardinals. J have placed it
for these reasons in a separate group.

Group of Pleurobema decisum.

Shell solid, inflated, ovate to elliptical, very inequilateral,
somewhat truncated in front and rounded or bluntly pointed
behind, wedge-shaped when looked at from above ; base slight-

758 PIL.EUROBEMA

ly angled in front, then nearly straight for two-thirds of its
length, from whence it curves to the posterior point; beaks
high, curved inward and forward; beak sculpture consisting
of a few coarse, irregularly concentric ridges, which curve
slightly upward behind; epidermis tawny to brownish, rayless,
the rest periods very distinctly marked by dark bands; pseudo-
cardinals stumpy, ragged, often showing a tendency to elonga-
tion in the direction of the axis of the shell.

Animal having the branchiz rather small, inner the larger,
free nearly or quite the entire length of the abdominal sac,
marsupium occupying all but the extreme posterior end of the
outer gills; branchiz and anal openings papillose.

PLEUROBEMA DECISUM (Lea).

Shell somewhat elongated, subtriangular, solid, inflated;
beaks high and full, placed close to the anterior end in young
shells, and projecting well in advance in the old ones; lunule
extending under the beaks; anterior end sometimes rounded
in young shells, sharply cut away below in old ones; base line
rounded; outline of the dorsal slope slightly curved or even
straight in old shells; posterior ridge not greatly elevated,
rounded or subangular, ending in a rounded point about at
the median line. In front of the posterior ridge there is a
wide, radial swelling that is much fuller than it is; epidermis
tawny to greenish-brown or brown, nearly or quite rayless,
often showing the dark rest marks very plainly, there are fre-
quently one or two broad, dark, dimly outlined rays at the
posterior part of the shell; pseudocardinals irregular, radial,
two in the left valve and three in the right; left valve with
two laterals ; right valve with a double one ; muscle scars small,
the anterior deep, the posterior round and impressed; beak
cavities shallow ; nacre silvery, thicker along the anterior base.

Length 8o, height 40, diam. 34 mm.

Alabama and Tombigbee River systems.

Type locality, Alabama River.

PILEUROBEMA 759

Unio decisus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 92, pl. x11,"
Aseeesee@bs., ll. 1634, op. «102, ph” xu,’ figs 23.——CoNraAD,
Monog., I, 1835, p. 6, pl. m1, fig. 2—HAnNtery, Biv. Shells,
1843, p. 187, pl. xxu, fig. 21—Kusrer, Conch. Cab. Unio,
1852, p. 41, pl. vu, fig..3—Cuenu, Ill. Conch., 1858, pl.
xvill, figs. 3, 3a, 3).—ReeEve, Conch. Icon., XVI, 1864, pl.
XVip fe 7 1.

Margarita (Unio) decisus Lea, Syn., 1836, p. 21; 1838, p. 18.

Margaren (Unio) decisus Lea, Syn., 1852, p. 26; 1870, p. 40.

Pleurobema decisa SIMPSON, Syn., 1900, p. 752.

Unio scalenius Say, Am. Conch., VI, 1834.

Unio anaticulus Lea, Pr. Ac. N. Sci. Phila., I, 1861, p. 40;
1 Ac: N.-ScioPhila., V,-1862, ‘p. 92, pl. x11, fig. 240; Obs.,
VIII, 1862, p. 96, pl. xin, fig. 240.—Sowerpsy, Conch, Icon.,
OV 1866) pl. xxvii -fioy 190.

Margaron (Unio) anaticulus Lea, Syn., 1870, p. 40.

Unio consanguineus Lea, Pr. Ac. N. Sci. Phila., VI, 1861, p.
boule, N-Scenremla WV; 1862)0p. 67) pl! vin, figs 217;
Obs., VIII, 1862, p. 71, pl. vu, fig. 217——SowerrsBy, Conch.
Icon., XVI, 1868, pl. Lxxvitt, fig. 409.

Margaron (Unio) consanguineus Lea, Syn., 1870, p. 40.

Unio crebrivittatus Lea, Pr. Ac. N. Sci. Phila., VI, 1861, p.
Goris Ac. Ni. Ser Phila Vi 18606, p. 43, ‘pl. xv; fig. 41;
Obs., XI, 1867, p. 47, pl. xv, fig. 41.

Margaren (Unio) crebrivittatus Lea, Syn., 1870, p. 40.

?Unic medius Reeve, Conch. Icon., XVI, 1864, pl. xvu, fig. 77
I have united a number of nominal species under the oldest

name. There is considerable variation in the form, the anterior
end being often rounded in young or almost adult shells, while
in old ones it is obliquely and strongly cut away below, leav-
ing the beaks to project well in advance of the rest of the
shell. The posterior end is generally bluntly pointed, but 1s
sometimes widely rounded, young shells or those almost adult
often have broad, dark green rest marks; they are rarely rayed,
but often have one or two irregular blotched rays on the hinder
part of each valve.

760 P1LEUROBEMA

PILEUROBEMA CHATTANOOGAENSE (Lea).

Shell subelliptical, subinflated or inflated, solid, very inequi-
lateral ; beaks full and high; lunule distinct ; posterior ridge low,
often scarcely marked; anterior end feebly truncate or evenly
rounded; base line curved; outline of dorsal slope generally
more nearly straight than that of the base; posterior end
rounded, sometimes bluntly pointed or slightly biangulate;
outline of shell when viewed from above wedge-shaped; epi-:
dermis tawny-brown, sometimes shaded green, usually having
the rest-marks very distinct; these and one or two ill-defined
rays on the posterior end are often dark green; pseudocar-
dinals irregular, radial, two in the left valve and three in the
right; laterals two in the left valve and a double one in the
right ; beak cavities shallow ; nacre white, iridescent behind.

Length 56, height 33, diam. 25 mm.

Alabama River system.

Type localitv, Chattanooga, Tenn.; Etowah, Oostanaula and
Coosawattee Rivers, Ga.

Unio chattanoogaensis Lmwa, Pr. Ac. N. Sci. Phila., I, 1858, p.
166; Jl. Ac. NoSet. Phila. 20V;:1850;p. 200) pl. xv neetoer,
Obs., VIT, 1859, p. 27, pl. xxv, fig. 90.—ReEEveE, Conch. Icon...
XVI, 1864, pl. xvi, fig. 60.

Margaron (Unio) chattanoogaensis Lea, Syn., 1870, p. 40.

Pleurobema chattanoogaensis StMPson, Syn., 1900, p. 753-
Although this approaches P. decisum so closely in some cases

that it is difficult to separate the two, I am inclined to believe
them distinct. This is a more distinctly elliptical shell at al!
ages than decisum, the beaks are not placed so far forward,
the anterior end, though sometimes truncate, is cut away little
if any below, the posterior end is not usually pointed but round,
and the growth marks are stronger and greener than in that
species. I am doubtful whether this form is found at Chat-
tanooga, Tennessee, as Dr. ea was informed. It is probably
confined to the drainage of the Alabama River system. Ac-
cording to T. H. Aldrich the animal of this and allied species
is a brilliant scarlet.

PI.EUROBEMA

“I
©)
-

PLEUROBEMA INTERVENTUM (Lea).

Shell irregularly oval or elliptical, subinflated, solid, inequi-
lateral ; beaks full and high; posterior ridge low; dorsal and
ventral outlines curved; region behind the ligament sometimes
elevated into a low angle; anterior end rounded or slightly,
almost squarely truncated; posterior end rounded or feebly
biangulate; epidermis tawny or tawny-brownish, often with
dark rest marks, sometimes with a few faint broken rays or
small dark ‘spots; pseudocardinals small, triangular, two in
the left valve and one to three in the right ; left valve with two
laterals ; right valve with a double one; beak cavities shallow ;
nacre white, iridescent and thinner behind.

Length 36, height 25, diam. 16 mm.

{Length 37, height 26, diam. 19 mm.

Type locality, Cahawba River, Alabama.

Unio interventus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60;
Hie AcoN. Sci Phila. V,.1962,p:, o#,, pl. x1, fie. 233% Obs;
VIET 1S62-peco, pis x1 e233.

Margaron (Unio) interventus LEA, Syn., 1879, p. 40.

Pleurobema interventus SIMPSON, Syn., 1900, p. 753.

Umo pallidofulvus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60;
ie AceNS set Phila? V5) 1662, p. 83, pl. xt, fig. 222; Obs.,
Vili, 1862; p::S7, pl. x1, fig. 232.

Margaron (Unio) pallidofulvus Lea, Syn., 1870, p. 40.

I cannot possibly separate this from the Unio pallidofulvus
and I do not know why Dr. Lea did so, as both were described
at the same time. The species is smaller than chattanoogaense,
it is shorter than that and not quite so inequilateral and it is
generally lighter colored.

PLEUROREMA MURRAYENSE (I.ea).

Shell oval, elliptical or subtriangular, solid, inflated, inequi-
lateral ; beaks full and high, the greatest diameter of the shel!
being just below them; posterior ridge low, narrowly rounded :
anterior end nearly squarely subtruncated or rounded; dorsal
and basal outlines curved, the latter usually more strongly so;
posterior end narrowly rounded ; epidermis dull, ashy or green-
ish-brown, with strong, sometimes greenish, rest marks;

762 PLEUROBEMA

pseudocardinals small, triangular, two in the left valve, three

in the right; laterals two in the left valve and a double one in

the right ; muscle scars small, impressed ; beak cavities shallow ;
nacre white.

Length 37, height 29, diam. 22 mm. (type)

Length 45, height 30, diam. 23 mm.

Coosa River system; Columbus, Georgia ?

Type locality, Connasauga Creek, Whitfield Co., and Eto-
wah River, Ga.

Umio murrayensis Lea, Pr. Ac. N. Sci. Phila., II, 1868, p. 143;
ji- Ac N. Sct; Philay Vl 18605 pp: 403) pl xiva tio, pense
Obs; So 1860, p62, plaxivi, hes Mis:

Margaron (Unio) murrayensis L&A, Syn., 1870, p. 40.

Pleurobema murrayensis SIMPSON, Syn., 1900, p. 753.

The type, whose dimensions | have given above, is not as
elongated as most specimens of this species are. The shell is
shorter than chattanoogaense, it 1s solider and more inflated
than imterzentum and is duller colored than either. It is close
to the troschelianum group.

Group of Pleurobema curtum.

Shell elongate, triangular, truncated in front, rounded on
the base, where it is quite full behind the middle, with a low
posterior ridge, the space between the middle of the disk and
the ridge flattened or sometimes slightly excavated, rather
sharply pointed behind ; umbonal region very prominent ; beaks
well forward: beak sculpture not observed; epidermis rather
smooth, brownish-olive; pseudocardinals distinct, triangular,
radiate; laterals heavy, slightly curved: cicatrices small and
deep ; nacre iridescent posteriorly. Animal with the gills large,
semicircular, the outer slightly larger than the inner, which
are free nearly their whole length from the abdominal sac;
marsupium occupying the entire length of the outer gills.

PLEUROBEMA CURTUM (Lea).

Shell subtriangular, solid, inflated, the beaks high and full,
placed nearly or quite at the anterior end, which below them
is squarely truncated; outline of dorsal slope nearly straight ;

PI.EUROVEMA 763

base rounded in front, cbliquely truncate behind; posterior
ridge low, ending behind in a point about on the median line ;
in front of the center of the shell there is a wide, radial swell-
ing; epidermis dark greenish-brown, greenish in the young
shell, often showing faint rest marks; pseudocardinals trian-
gular, radial, three in the right valve and two in the left; lat-
erals two in the left valve and a double one in the right ; beak
cavities shallow ; muscle scars small, impressed; nacre bluish-
white, thin and iridescent behind.

Length 47, height 34, diam. 24 mm.

Type locality, Tombighee River, Columbus, Mississippi.

Uniaveurins Ins Pr. Ac. IN. Sei Phila., Tl; 1850,. p..112); Jl.
New Noein bila: Vi51S02, pxlO3.pl.. XVvil, fig. -253;< Obs.,

VEE S625 p.4107,.pl. xvii fie: 252:

Margaron (Unio) curtus Lea, Syn., 1870, p. 40.
Pleurobema curta SIMPSON, Syn., 1900, p. 754.

The radial swelling at and in front of the middle of the shell
is strong and wide. Behind it the shell is compressed and the
base line is straight or even a little incurved. The anterior
truncation is square. ‘The form and the dark epidermis will
distinguish it from all other species.

Group of Pleurobema troschelianum.

Shell rather small, solid, rounded-triangular, inflated, some-
what inequilateral, slightly pointed near the posterior base,
and rounded angular at the hinder end of the ligament; base
of the shell almost evenly rounded; posterior ridge low; beaks
high and slightly curved inward and forward over a well-de-
fined lunule; epidermis dull tawny, showing the rest periods
and occasionally marked with a radiating row of dark green,
squarish spots in front of the posterior ridge; hinge plate wide
and ‘lat; pseudocardinals small, triangular, rough; laterals
short. curved: muscle scars small, rather deep. Animal with
semicircular gills, the inner the larger and free from the ab-
dominal sac half to nearly their whole length; ovisacs of outer
gills apparently in pairs.

764 PLEUROBEMA

PLEUROBEMA TAITIANUM (Lea).

Shell obliquely triangular, solid, inflated; beaks very full
and high, placed at or in advance of the anterior end of the
shell; anterior end obliquely truncated, sometimes showing an
almost double lunule, rounded below ; base line straight ; post-
dorsal line only slightly curved; posterior ridge low, ending in
a rounded point near the base of the shell; in front of the
posterior ridge there is a wide, radial swelling; surface with
uneven, concentric ridges; epidermis tawny or tawny-brown,
scarcely shining; pseudocardinals broken up, solid, ragged,
two in the left valve and one, with often one or more small
ones, in the right; laterals irregular, two in the left and a dou-
ble one in the right; muscle scars small, deep; beak cavities
shallow ; nacre white or pink, thin and iridescent behind.

Length of type 40, height 40, from beak to post-basal point
45, diam. 26 mm.

Length 52, height 48, diam. 24 mm.

Type locality, Alabama River.

Unio taitianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 39, pl. rv,
hg. 11; Obs., I, 1834, p. 151, pl. rv, fig. 11.—Hantey, Biv.
shells, 1243, po 186, plaxxann fie. 26.

Margarita (Unio) taitianus Lea, Syn., 1836, p. 21; 1838, p. 18.

Margaron (Unio) taitianus Lea, Syn., 1852, p. 25; 1870, p. 38.

Pleurobema taitiana SIMPSON, Syn., 1900, p. 754.

This shell bears a most striking superficial resemblance in
shape to Quadrula pyramidata, but the epidermis is very differ-
ently colored and the beak cavities are unusually shallow, while
in QO. pyramidata they are deep and compressed. A specimen
from Claiborne, Alabama, in the Lea collection has rich pink
nacre.

PLEUROBEMA TOMBIGREANUM Frierson.

“Shell short, triangular, thick, solid and heavy; truncated
in front, roundly pointed behind at the post-base. Beaks high
and incurved, their sculpture not seen. Post-ridge rounded
and close to post-margin. The sides are slightly flattened just
in front of the post-ridge and an inflated, raised area extends

PILEUROBEMA 765

from the beaks to the anterior base. his area is to a consid-
erable degree concentrically sulcated, the sulci becoming obso-
lete behind. where it becomes striated; epidermis rayless, dark
reddish-brown or having faint, greenish rays near the beaks.
Lunule triangular and membranaceous. ‘The shell is remark-
ably flattened in front, half way from beaks to base, showing a
sort of so-called “secondary lunule.’”’ Nacre white, to rose-
color and iridescent. Muscle scars well impressed and sepa-
rate. Beak cavities shallow. In the left valve there are two
low, thick, curved laterals, somewhat striate, and a stout, up-
right, bifid, striate, acuminate cardinal. In the right valve,
a single low, stout, curved lateral upon a very wide, heavy
plate or shelf and a wedge-shaped cardinal arising from a pit
surrounded by a semicircular, low ridge. Cardinal plate thick,
on the inner surface of which may be noted the dorsal muscle
scars.

Length 48, alt. 40, diam. 32.3 mm.

Length 41, alt. 39, diam. 27.5 mm.” (Frierson).

Type locality, Tombigbee River, Demopolis, Marengo Co.,
Ala. Also found at Columbus, Miss., and in the Alabama
River.

Pleurobema tombigbeanum Frierson, Naut., XXII, 1908, p.

27, OLoMt, hes 13+ A.

“The shell may be mistaken by the casual observer for a
small Ouadrula pyramidata Lea, but may be easily distinguish-
ed by its smaller size and especially its shallower beak cavities,
lower beaks and less pronounced sulcus from beak to post-
base. It seems to be a rather rare shell in the Tombigbee and
Alabama rivers. Compared with P. taitianwm Lea ours is less
convex, with a more or less distinct sulcus back of the convex-
if ig

PI.UROBEMA Cor (Conrad).

Shell obliquely subtriangular, solid, inflated, inequilateral ;
beaks very high, full and rounded; anterior end slightly trun-
cated above, sometimes almost angled in the middle, base line
decidedly rounded; outline of the dorsal slope curved; pos-

766 PILEUROBEMA

terior ridge rounded, ending behind near the base in a rounded
point; surface irregularly, concentrically striate; epidermis
tawny or tawny-brown; pseudocardinals triangular, two in the
left valve and three in the right; laterals two in the left valve
and a double one in the right; beak cavities shallow; muscle
scars small and impressed; nacre silvery-white, iridescent he-
hind.

Length 35, height vertically from the beaks 38, from beak:
to post-basal point 43 mm.

Alabama River system; Flint River, Georgia.

Type locality, Elk and Flint Rivers, Ala.

Unio mytilloides Conrap, Am. Jl. Sci., XXV, 1834, p. 343, pl-
1, HIS 7

Unio cor Conran, New F. W. Shells 1834, p. 28, pl. 111, fig. 3.
—CneENu, Bib. Conch., 1st ser., JI], 1845, p. 16, pl. 11, fig:
2.

Margarita (Unio) cor Lma, Syn., 1836, p. 21; 1838, p. 18.

Margaron (Unio) cor Lua, Syn., 1852, p. 26; 1870, p. 39.

Pleurobema cor SIMPSON, Syn., 1900, p. 754.

Unio crapulus Lua, Pr. Ac. N. Sci. Phila., V, 1861, p. 39; Jl.
Ac. N..Sci. Phila: V1.W1866, ‘p..42, pi xvachs: 40: Obs ae
1867, p. 46, pl. xv, fig. 40.

Margaron (Unio) crapulus Lea, Syn., 1870, p. 41.

Umolewisu les, Pr. Ac; N. Sei. Phila, V5 1861, p: 40: Ave
N;.sci Phila.y V5 1862, p:.75,.pl> want, tic 220 Obs, Wine
1862, p. 75, pl. Vull, 1ig220:

Margaron (Unio) lewisti LEA, Syn., 1870, p. 56.

Conrad’s shell is evidently fully adult or old; Lea’s U. lewis
and crapulus are young or barely adult specimens of what
seem to me to be the same. The species is less angular than
P. taitanum, and the disk is evenly swollen, there being no
compression in front of the posterior ridge.

Conrad says this is between Unio ellipsis Lea and mytiloides
Rafinesque, but that he has no doubt that it is the latter. It
is certainly very different from the shell Rafinesque figures
and describes as Pleurobema mytiloides. (Am. Gen. Sci.
Phys. Brux., XII; 1820, p. 313) pl. 1x%x11,; fies, 6-10). iCan-

PL_EUROBEMA 767

rad’s Unio cor was published in May, 1834, and his mytilloides
in January of the same year, so that the latter has priority,
but as Rafinesque’s name was placed under the genus Pleuro-
bema, and as I place Conrad’s species, which is an entirely
different thing, in the same genus, the name mytilloides can
not be used for it, and it must therefore take the next name
proposed, which is Conrad's cor.

Dr. Lea admits Rafinesque’s mytiloides with doubt, and in
his collection places under that name specimens which I regard
as a rather elongated Quadrula pyramidata. Rafinesque’s
figure represents an elongated shell, almost absolutely straight
on the dorsal line, and with the beaks carried far in front of
the rest of the shell. I have never seen anything which at all
agrees with it.

PLEUROBEMA PEROVATUM (Conrad).

Shell irregularly oval, inflated, rather thick, inequilateral ;
beaks full, high and rounded, undulated, placed not very near
the anterior end; anterior end rounded, slightly cut away be-
low; base line curved; post-dorsal line raised into a decided
angle at some distance behind the ligament; below this angle
the posterior end is obliquely truncate; posterior ridge narrow-
ly rounded; epidermis olive; pseudocardinals erect and promi-
nent, not very thick; laterals straight, compressed; anterior
muscle scars deep; posterior scars impressed; nacre white,
much thinner behind.

Length ef Conrad’s figure 44, height 30 mm.

Tvpe locality, Prairie Creek, (tributary of the Tombigbee),
Marengo County, Alabama. Also small streams, Greene Co.,
Ala.

Unio perovatus Conrap, Am. Jl. of Sci, XXV, 1834, p. 338,
pl. 1, fig. 3; ?New F. W. Shells, 1834, p. 47, pl. 1, fig. 3.—
€Henw, Bib. Conch., rst. ser., II; 1845, p. 22, pl. 1, fig: 3.

Margarita (Unio) perovatus IA, Syn., 1836, p. 23; 1838, p.
10.

Margaron (Unio) perovatus Tea, Syn., 1852, p. 27; 1870, p.
42.

Pleurobema perovata Simpson, Syn., 1900, p. 755.

768 PLEUROBEMA

I have never seen what | felt certain was a specimen of this
species and am at a loss to know just where to place it. Conrad
states that “the young shell is broader behind, approaching to
an oval figure, and is prettily ornamented with green rays on
an olive-yellow ground.” His figure in the New Fresh Water
Shells is considerably different from the one in the American
Journal of Science, but the former may be from a younger
shell. The high broadly rounded, mammillar beaks, placed at
some distance from the anterior end and the rather decided
angle behind the ligament are distinguishing characters.

PLEUROBEMA NUCLEOPSIS (Conrad).

Shell short elliptical, subinflated, solid, inequilateral; beaks
moderately full and high; posterior ridge scarcely developed,
widely rounded ; anterior end almost evenly rounded; base and
dorsum curved : posterior end rounded ; surface nearly smooth ;
the rest marks a little depressed; epidermis tawny or tawny-
brown with a row of small green spots on the posterior ridge
in the young shell, dirty brown in the old state; pseudocardi-
nals triangular; laterals short, stout, that of the right valve
partly double; muscle scars small; beak cavities shallow ; nacre
bluish-white.

Length 30, height 24.5, diam. 15 mm.

Length 46, height 39.5, diam. 24 mm.

Coosa River system.

Type locality, Etowah River, Ga.

Unio nucleopsis Conrap, Ann. and Mag. Nat. Hist., IV, 1840,
p 2013: JL Ac Nw Sci Phila, 1) 850, p..276, pease ee
8r.— Kusrer, Conch. (Cab, Unio, 1801) piety) piaenmen tie
fig. 3. Reeve, Conch. Icon., XVI, 1864, pl. xv1, fig. 68.

Margaron (Unio) nucleopsis Lua, Syn., 1852, p. 35; 1870, Pp.
56.

Pleurobema nucleopsis SIMPSON, Syn., 1900, p. 755.

Conrad’s figure is evidently taken from a young shell and
shows it to be almost evenly short elliptical. A specimen in
the Lea collection about the size of Conrad’s figure, bearing
the name Unio nucleopsis Conrad, agrees very well with the
figure of that species but is somewhat broken behind. Lea

PLEUROBEMA 769

has several older shells with the same name, but most of them
are perhaps something else. The species is more evenly ellip-
tical than P. irrasum, but I am doubtful whether it is distinct.

PIEUROBEMA STABILE (Lea).

Shell subovate, subelliptical or subtriangular, solid, inflated,
somewhat inequilateral; beaks high, full and rounded; lunule
narrow ; anterior end evenly rounded; base line curved; out-
line of the dorsal slope curved, sometimes raised behind the
ligament into a low angle; posterior ridge rather low, slightly
double below, ending at and below the median line in a faint
biangulation; surface with irregular, concentric striz ; epider-
mis tawny or tawny-brownish, rarely with a broken row of
squarish green blotches: pseudocardinals ragged, triangular,
two in the left valve and one to three in the right; laterals
two in the left valve and a double one in the right; beak cav-
ities shallow; muscle scars small, impressed; nacre whitish,
slightly iridescent behind.

Length 36, height 27, diam. 22 mm.

Length 43, height 33, diam. 27 mm.

Type locality, Coosa River, Alabama.

Umino staihsyiean, Pr: Ac. .N. sei. Phila., V,. 1861, p. 59; Jl.
ie Ne oci Phta.2V Eso2./pie71, pk. viii, fis) 221; Obs.
VIII, 1862, p. 75, pl. vii, fig. 221.

Margaron (Unio) stabilis Lea, Syn., 1870, p. 38.

Pleurobema stabilis SIMPSON, Syn., 1900, p. 755.

Umo medus Lua, Pr. Ac. N. Sci. Phila., V., 1861, p./ 40% Jl.
ACN. oc Emila.), 1802, p. 7euplax, fig, 227:;-Obs.,. VEIL,
1862, p. 82, pl. x, fig. 227.—Sowerpy, Conch. Icon., XVI,
1500, pl Lxxmr, fic. 375:

Margaron (Unio) medius Lea, Syn., 1870, p. 40.

A species with no very striking characters. Lea’s Unio
medius seems to me to be only the younger shell of his stabilis,
which appears to be adult. The high, full, rounded beaks
placed at some distance back from the anterior end sometimes
give the shell a somewhat triangular outline. ‘The double pos-
terior ridge and faint biangulation where it ends behind are
constant characters in all the specimens IT have seen.

770 PLEUROBEMA

PLEUROBEMA TROSCHELIANUM (Lea).

Shell irregularly elliptical, subtiiangular or subovate, some-
what inflated, rather solid; beaks full, rather high and round-
ed, placed near the anterior end; anterior end rounded or
slightly obliquely truncate above; base and dorsal outlines
rounded, the Jatter sometimes raised almost to an angle behind
the ligament; posterior ridge well developed, narrowly round-
ed, slightly double below, ending near the base in a faint bian-
gulation ; epidermis tawny to dirty greenish-brown, sometimes
with a single, broken ray near the posterior ridge; pseudocar-
dinals small, stumpy; two in the left valve and one to three
in the right: iaterals two in the left valve and a double one in
the right; beak cavities shallow ; muscle scars small, impress-
ed; nacre whitish, thinner and iridescent behind.

Length 4o, height 28, diam. 21 mm.

Alabama River system.

Type locality, Coosawattee River, Murray Co., Ga.

Unio troschelianus Lua, Tr. Am. Phil. Soc., X, 1852, p. 280,
ply Xxim, fig’ 390: VObs.,. Vo18525p. 30). pl Soxtiiee ao:
Margaron (Unio) troschelianius Lea, Syn., 1852, p. 26; 1870,

p. 40.

Pleurobema troscheliana SIMPSON, Syn., 1900, p. 750.

Close to stabile, but less inflated, less solid, having a stronger
posterior ridge and a darker epidermis with a tint of dirty
green. It is more elongated than irrasum or alium.

PLEUROBEMA JRRASUM (Lea).

Shell subtriangular, short, rather inflated, solid, slightly in-
equilateral; beaks full, high, rounded; anterior’ end rounded.
slightly obliquely truncate above; base line rounded; outline
of dorsal slope somewhat curved, elevated into a low angle
behind the ligament; posterior ridge well developed, narrowly
rounded, ending in a rounded point below the median line ; epi-
dermis dirty greenish-brown, rarely with vestiges of rays;
pseudocardinals subtriangular, two in the left valve, one to
three in the right; laterals short, two in the left valve and a

PLEUROBEMA gpa

double one in the right; muscle scars small, impressed; beak

cavities shallow ; nacre white, thinner and iridescent behind.
Length 35, height 28, diam. 20 mm.

Length 44, height 35, diam. 29 mm.
Coosa River system.
Type locality, Etowah River, Ga.

Unio irrasus Lua, Pr. Ac. N. Sci. Phila., V, 1861, p. 38; Jl.
Ac N= sect. Phila. V_1862,-p. or, pl. x11, fig: 239% Obs.,
VIII, 1862, p. 95, pl. x1u, fig. 230.

Margaron (Unio) irrasus Lea, Syn., 1870, p. 38.

Pleurobema irrasa SIMPSON, Syn., 1GO0, p. 756.

Close to troschelianum, but it is not so elongated, it is more
nearly triangular and the beaks are nearer the center of the
shell. It is quite likely that the two forms may run together.

PLEUROBEMA ALTUM (Conrad).

Shell suborbicular or somewhat subtriangular, inflated, solid,
subequilateral; beaks high, full and rounded; anterior end
nearly evenly rounded, sometimes very faintly subtruncate
above ; base line much rounded; outline of dorsal slope slightly
curved, raised into a slight angle behind the ligament ; poste-
rior ridge strong, narrowly rounded, generally narrowly double
below, ending below the median line in a narrow biangulation ;
surface with irregular growth lines; epidermis dirty tawny or
tawny-brown, sometimes having a few faint, squarish, green
spots; pseudocardinals subtriangular, two in the left valve,
one to three in the right; laterals very short and heavy; two
in the left valve and a double one in the right; beak cavities
shallow; muscle scars small, deep; nacre white, thinner and
iridescent behind.

Length 35, height 33, diam. 21 mm.

Alabama River system.

Type locality, Tennessee. ?

Unio altus Conran, Jl. Ac. N. Sci. Phila., II, 1854, p. 298, pl.

XXVU, fig. 5.

Margaron (Unio) altus Lea, Syn., 1870, p. 42.
Pleurobema alta Stmpson, Syn., 1900, p. 756.

792 PLEUROBEMA

Unio tibulcides Lata, Pr. Ac. N. Sci. Phila., III, 1859, p. 154;
Jl. Ac N.Sei: Philas VV,:1850; poe to pl: xexvinehie toe;
Obs., VII, 1859, p. 37, pl. Xxvu, fig. 100 —Sowerrpgy, Conch.
Icon., X V1, 1866, pl. x11, fie. 223:

Margaron (Unio) fibuloides Lea, Syn., 1870, p. 56.

Very close to irrasum, but shorter, rather more nearly round,
solider and having a more tawny epidermis. Conrad’s Unio
altus is apparently a light-colored young shell, having a ray
on each valve broken into squarish spots.

PLEUROBEMA HARTMANIANUM (Lea).

Shell almost triangular, inequilateral, inflated, solid; beaks.
full and high, turned a little forward; anterior end generally
obliquely truncate above, rounded below; base line slightly
curved; outline of dorsal slope curved, elevated to a low angle
behind the ligament; posterior ridge well developed, angled
above, somewhat double below, ending near the base in a bian-
gulation; surface rudely and unevenly concentrically sculp-
tured, epidermis tawny to tawny-brown; pseudocardinals rag-
ved, two in the left valve, three in the right; laterals strong,
two in the left valve and a double one in the right; beak cav-
ities shallow, compressed; muscle scars small, deep; nacre
white, thinner and iridescent behind.

Length 50, height 51, diam. 35 mm.

Coosa River, Alabama.

‘Type locality, Coosa River, Wetumpka, Ala.

Unio haritmanmianus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p.
307.> Jl, Ac. Nu Scis Phila, Vji862, p.73;, ple wan; fie ear
Obs., VI, 1862)'p.'77; pl; vant, Hes 222:

Margaron (Unio) hartmanianus Lea, Syn., 1870, p. 38.

Pleurobema hartmaniana Simpson, Syn., 1900, p. 756.

Close to taitianwm, but not so high, the outline being near to
an equilateral triangle while that of faitianwm is an inequilat-
eral triangle. ‘There are, however, intermediates, which hint
strongly at a connection of the two. The two forms differ
pretty constantly from P. cor in having a decided posterior
ridge, in front of which the disk is flattened. In cor the pos-

7

PLEUROBEMA 773

terior ridge is feebly developed and the disk in front of it is

full.

Dr. ea has shells in his collection from the Clinch River,
which he places with this species, which I am certain belong
to the clava group. .
PLEUROBEMA INSTRUCTUM (Lea).

Shell subtriangular, convex to subinflated, inequilateral, sub-
solid: beaks high, rather full, their sculpture a few strong, ir-
regular ridges that curve up decidedly behind; anterior end
evenly rounded; base line slightly curved; outline of dorsal
slope curved, raised into an angle behind the ligament; pos-
terior ridge high, somewhat narrowly double, ending in a bian-
gulation near the base: surface unevenly, concentrically striate,
epidermis pale greenish-tawny ; pseudocardinals small, two in
the left valve, one to three in the right ; laterals two in the left
valve and one in the right. the latter somewhat double; beak
cavities shallow ; muscle scars small, not deep; nacre white or
bluish-white, silvery or iridescent behind.

Length 38, height 30, diam. 17 mm.

Length 35, height 28. diam. 19 mm.

Type locality, Cahawba River, Alabama.

Unaorinstructus Ea Pra Ac. IN. Sct. Phila. V, 1861, p. 59;
iseAcw IN oct e aids. Vv .1S02. pp: o2.\pl. x, fie: 230% Obs.,
VI, 1862, p. 86, pl. x, fig. 230.

Margaron (Unio) instructus Lea, Syn., 1870, p. 38.

Pleurobema instructa SIMPSON, Syn., 1900, p. 756.

Thinner and less inflated than any of the nearly related spe-
cies. In fresh specimens the epidermis is often somewhat
cloth-like.

Group of Pleurobema showalterit.

Shell small, rounded triangular, inflated, slightly truncated
anteriorly, posterior end arched and ending in a bluntly round-
ed point at the post-base, posterior ridge well defined ; umbonal
region full; beaks rather prominent, the sculpture not observ-
ed: epidermis brown, not rayed; hinge plate rather wide:

774 PLEWROBEMA

pseudocardinals small, triangular, radial, roughened; laterals

short, heavy ; nacre white, brilliantly iridescent posteriorly.

Animal apparently having ovisacs in pairs, which are slight-
ly wavy and lirate at the base; gills rather large, semicircular,
inner much the larger, partly free from the abdominal sac;
mantle thin, thickened at edge, and bordered with a dark line.
PLEUROBEMA SHOWALTER (Lea).

Shell subtriangular to suborbicular, inflated, very solid, in-
equilateral, or equilateral; beaks high and full; posterior ridge
generally well developed, narrowly rounded, usually ending
in a blunt point below the median line; anterior end rounded
or slightly subtruncate above, base more or less rounded ; pos-
terior outline curved ; surface with irregular growth lines ; epi-
dermis tawny to dark greenish-brown, sometimes feebly rayed ;
pseudocardinals subtriangular, two in the left valve and one
to three in the right; left valve with two short laterals; right
valve with a double one; beak cavities very shallow; muscle
scars smal!, deep; nacre whitish, sometimes tinted with purple,
thicker in front.

Length 32, height 30, diam, 20 mm.

Length 31, height 33, diam. 24 mm.

Coosa River, Alabama.

Type locality, Coosa River, Wetumpka, Ala.

Unio showalterii Lea, Pr. Ac. N. Sci. Phila., [V, 1860, p. 307 ;
jiAc NeSer, Phila.“ 1862; *p:-73,-pl) vin, te 223. Obs.
VIII, 1862, p. 77, pl. vin, fig. 223.—Sowersy, Conch. Icon.,
XVI, 1868, pl. 1.xxx1, fig. 426.

Margaron (Unio) showalterti LEA, Syn., 1870, p. 55.

Pleurobema showalterii SIMPSON, Syn., 1900, Pp. 757.

This species varies from subtriangular to almost orbicular
and considerably in the degree of inflation. It is generally
dark greenish-brown, though occasional specimens show a
flush of tawny-color. Some shells appear almost exactly on a
casual view like young Quadrula solida or pyramudata, but the
almost total want of beak cavities will at once distinguish them
and the shell is solider than the voung of either of them.

PIL.EUROPEMA

“I
~
cn

Group of Plewrobema nuv.

Shell oval, inflated, moderately solid, with a low posterior
ridge, swollen at the post-basal part; posterior end pointed at
the termination of the posterior ridge; beaks full, rather high,
considerably removed from the anterior end; epidermis pale
to dark brown, rest lines very distinct; pseudocardinals small,
stumpy, radiate, rough; laterals straight; nacre brilliantly iri-
descent posteriorly; front part of shell heavy, suddenly be-
coming thinner behind.

Animal unknown.

PLEUROBEMA VERUM (Lea).

Shell subovate or subtriangular, subinflated, subsolid, inequt-
lateral; beaks elevated, moderately full; anterior end rounded
or slightly truncated above; base line curved; outline of dor-
sal slope curved, subangulate just behind the ligament; pos-
terior vidge well developed, narrowly rounded, ending in a
blunt point above the base; surface with uneven growth lines ;
epidermis dull tawny-brown to greenish-brown, generally
showing the rest marks; pseudocardinals small, two in the left
valve and one to three in the right; two laterals in the left
valve and a double one in the right; muscle scars impressed ;
beak cavities rather shallow ; nacre whitish.

Length 50, height 40, diam. 23 mm.

Black Warrior and Cahawbha rivers, Alabama.

Type locality, Cahawba River, Perry Co., Ala.

Unio verus Lea, Pr. Ac. N. Sci. Phila., V, 1860, p. 140; Jl. Ac.
Ne Sct) Phila 1862; -p.' 83, phix1 fie. 231 ;- Obs.,. VIL,
[o62) p87 .pl. SL, fe! 230

Margaron (Unio) verus Lea, Syn., 1870, p. 38.

Pleurobema vera SIMPSON, Syn., 1900, p. 757.

The type is a young shell, and seems to stand between the
troschelianum and nux groups, and to show some relation to
that of Pleurobema argenteum. The shell is only moderately
solid and inflated.

776 PLEUROBEMA

PLEURGBEMA HAGLERI Frierson.

Shell subelliptical, subinflated, inequilateral; beaks only
moderately full and high; posterior ridge well developed, slight-
ly double below, ending at and below the median line in a
feeble biangulation ; anterior end almost evenly rounded; base
line curved, quite full just behind the middle; outline of dor-
sal slope curved, a little more prominent just behind the liga-
ment than elsewhere; surface with irregular growth lines; epi-
dermis pale to rather dark reddish-brown, often very faintly
rayed, scarcely shining ; pseudocardinals triangular, two in the
left valve, one to three in the right; two laterals in the left
valve and a scarcely double one in the right; beak cavities
shallow; muscle scars of moderate size, impressed; nacre
whitish, purplish or salmon-red, thinner and iridescent behind.

Length 47, height 34, diam. 20 mm.

North and Black Warrior Rivers, Alabama.

Type locality, North River, Tyner, Ala.

Unio (Pleurobema) hagleri Frierson, Naut., XIII, 1900, p.

TOO}, ply 1:

Pleurobema haglert StMPsoN, Syn., 1900, p. 757.

This species has no strong characters, yet it does not seem
to be referable to anything else. It is larger, less solid and
inflated than what I take to be Conrad’s Unio rubellus; it 1s
lighter colored than that species. It is much lighter colored
apparently than his U. furvus and does not have the minute,
crowded wrinkles he mentions as belonging to the latter spe-
cies. It may be a mere variety of furvus. The swelling just
behind the middle of the base differentiates it from the Unio
fassinans of Lea, to which it bears some resemblance.

PLEUROBEMA RUBELLUM (Conrad).

Shell rather small, inflated, solid, somewhat triangular or ir-
regularly elliptical, slightly inequilateral ; heaks full, high; an-
terior end usually obliquely subtruncate above, slightly cut
away below, narrowly rounded in the middle; base line
strongly curved, unusually full in most cases at the middle;
outline of the dorsal slope curved; posterior ridge well devel-

PLEUROBEMA ar

oped, narrowly rounded, ending in a blunt point below the

median line; epidermis scarcely smooth, reddish-brown; pseu-

docardinals triangular, two in the left and one to three in the
right valve; beak cavities shallow; muscle scars rather small,
impressed ; nacre whitish, thinner behind.

Length 33, height 27, diam. 22 mm.

Length 32, height 24, diam. 17.5 mm.

Black Warrior and Cahawba Rivers, Alabama.

Type locality, Black Warrior River, near its source.

Unio rubellus Conrav, New F. W. Shells, 1834, p. 38, pl. vr,
fig. 2—CHENU, Bib. Conch., rst ser., III, 1845, p. 20, pl. 11,
fig. 2.

Margarita (Unio) rubellus Lea, Syn., 1836, p. 33; 1838, p. 28.

Margaron (Unio) rubellus Lea, Syn., 1852, p. 34; 1870, p.

Pleurobema rubella Simpson, Syn., 1900, p. 757.

Unio rudis Conrad, Monog., No. 9, 1837, p. 76, pl. XLiIl, fig. I.

Unio pulvinulus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164; Tr.
Mitieee mike Oe, Sy loio. pO: Ot, pl. vill, fic. 24; Obs., EV;
1945; ps 55, pl. viti, ig: 24:

Margaron (Unio) pulvinulus Lua, Syn., 1852, p. 26; 1870, p.
Al.

[ have before me a large number of shells from the above
two rivers that agree in all essential characters with Conrad’s
Umo rubellus. It is a small, very solid, inflated form with a
reddish-brown, rayless, almost rough epidermis, and_ with
white nacre in all the examples I have seen.

ot
on

PLEUROBEMA FURVUM (Conrad).

Shell somewhat obovate, solid, subinflated or inflated, in-
equilateral; beaks rather full and high; anterior end a little
narrowed and rounded; base line curved, fullest just behind
the middle; outline of dorsal slope rounded, sometimes raised
almost to an angle at the hinder end of the ligament ; posterior
ridge rounded, ending in a point at or below the median line;
surface with uneven, concentric sculpture; epidermis reddish-
brown, dark brown or nearly black with very fine, crowded,
concentric wrinkles, dull to subshining; pseudocardinals tri-

778 PLEUROZEMA

angular, two in the left valve and one to three in the right;

laterals two in the left valve and a somewhat double one in the

right; beak cavities shallow; muscle scars rather small, im-

pressed; nacre white or reddish, thinner and iridescent behind.

Length 50, height 40, diam. 30 mm.

Length 509, height 39, diam. 26 mm.

Type locality, Black Warrior River, Alabama.

Unio furvus ConRAD, New F. W. Shells, 1834, p. 39, pl. v1,
fig. 3—CHENUu, Bib. Conch., ist ser., III, 1845, p. 20, pl. 1,
fig. 4.

Pleurobema furva SIMPSON, Syn., 1900, p. 758.

I cannot be positive that the shells, which I call Pleuwrobema
furvum, are Conrad’s Unio furvus, but I think they are. They
agree well in shape; some of them are quite dark and they
have the epidermis beautifully and minutely concentrically
wrinkled, a character he notes in his description. He gives
no dimensions, but if the shells I have are that, his figure is
taken from a young specimen, as it is 32 millimeters long and
18 high.

PLEUROBEMA AVELLANA Simpson.

Shell small, solid, inflated, inequilateral, nearly elliptical ;
beaks full, slightly elevated; posterior ridge well developed,
narrowly rounded, ending below the median line; anterior end
evenly rounded ; base line curved, a little fuller in the middle ;
outline of dorsal slope almost evenly curved, the posterior end
narrowly rounded ; surface lightly concentrically striate, green-
ish-brown, slightly clouded but scarcely rayed ; pseudocardinals,
two in the left valve and one in the right; laterals, two in the
left valve and one in the right, which is somewhat double;
muscle scars deep; nacre bluish, iridescent behind.

Length 30, height 20, diam. 15 mm.

Type locality, Cahawba River, Alabama.

Pleurobema avellana Stmpson, Pr. Ac. N. Sci. Phila., 1900,

D. Ol, pl 1s. (6, 7; Syn), OOO mp7 Se.

A small, compact, solid, inflated species, which is more
nearly elliptical than P. rubeliam and differently colored.

PLEUROREMA 779

P).2UROBEMA NUX Lea.

Shell small, solid, inflated, inequilateral, irregularly ellipti-
cal or ovate; beaks high and full, with two or three strong,
irregular ridges ; anterior end evenly rounded; base line curved,
fullest just behind the middle; outline of dorsal slope evenly
curved or raised almost to an angle behind the ligament ; pos-
terior ridge low but well marked, subangular or narrowly
rounded, ending in a point at the median line; in front of it
the shell is much swollen ; epidermis greenish-brown to reddish-
brown, often showing the dark rest marks, almost cloth-like
in fresh shells; pseudocardinals triangular, two in the left
valve and one to three in the right; two laterals in the left
valve and a somewhat double one in the right; beak cavities
small; muscle scars impressed; nacre bluish-white, thinner
and iridescent behind.

Length 42, height 29, diam. 21 mm.

Alabama River system.

Type locality, Alabama River.

Unio nux Lea, Tr. Am. Phil. Soc., X, 1852, p. 283, pl. xxiv,
ne. 43; Obs., V, 1852; p: 30; pl: Xx1v, fig, 43.

Margaron (Unio) nux Lea, Syn., 1852, p. 31; 1870, p. 49.

Pleurobema nux SIMPSON, Syn., 1900, p. 758.

Unio cinnamomicus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 39;
iaAc Ne set Phila. V 71862). p. 100; pl: xvi; fig. 248. Obs:.
VIII, 1862, p. 104, pl. xvi, fig. 248.

Margaron (Unio) cinnamoniinus, Lea, Syn., 1870, p. 40.

Unio cinnamominus Sowrrry, Conch. Icon., XVI, 1868, pi

LXXXIIt, fig. 436.

I cannot see that cinnamomicus differs in any way except in
having a reddish-brown epidermis. Between this and typical
nux there is a complete blending in the matter of color. This
differs from avellana in having a decided point on the median
line behind.

PLEUROBEMA JOHANNIS (Lea).

Shell irregularly, elliptical, subrhomboid or subovate, sub-
inflated or inflated, inequilateral, solid; beaks full and high;
posterior ridge much less inflated than the disk in front of it.

780 PLEUROBEMA

subangular or narrowly rounded, ending at or below the me-
dian line in a blunt point; anterior end evenly rounded; base
line curved, fuller behind the middle; outline of dorsal slope
curved, raised to an angle behind the ligament; surface nearly
smooth; epidermis greenish-yellow, clouded or irregularly
marked with broad bands of rich green and these are broken
by faint, light rays; rest marks often distinct ; pseudocardinals
two in the left valve and three in the right; laterals two in the
left valve and a somewhat double one in the right; muscle scars
small; beak cavities shallow; nacre bluish-white, thinner and
iridescent behind.

-Length 37, height 23, diam. 18 mm.

Alabama River system.

Type locality, Connasauga and Etowah Rivers, Ga.

Umo johannis Lea, Pr. Ac. N? Scr Phila, TEL 1Ss5o.ap= 1705
jl Ac: NaScu ‘Phila, 1V.1860ep. 340. pla hve iS. foe sO Ds
VIII, 1860, p. 25, pl. Lv, fig. 168.

Margaron (Unio) johannis Lea, Syn., 1870, p. 41.

Pleurobema johannis StmMpson, Syn., 1900, p. 759.

Shorter and solider than P. flavidulum and having a very
different color pattern from it or P. hanleyanum. ‘The largest
specimen I have seen is covered all over with what appears
like low blisters of the epidermis, but this character is not
present in other shells I have seen.

PLEUROBEMA HANLEYANUM (Lea).

Shell irregularly elliptical, subinflated to inflated, inequilat-
eral, rather solid; beaks full and high; posterior ridge low,
narrowly rounded, ending in a blunt point about at the median
line; in front of the ridge the disk is decidedly inflated; ante-
rior end rounded; base curved, full behind the middle; outline
of the dorsal slope curved, most elevated behind the ligament ;
epidermis brownish or greenish-brown, somewhat cloth-like,
showing the dark rest marks plainly ; pseudocardinals triangu-
lar, two in the left valve and one to three in the right; two
short laterals in the left valve and a more or less double one

PILEUROBEMA 781

in the right; beak cavities shallow; muscle scars small; nacre

white or bluish, thin and iridescent behind.

Length 37, height 24, diam. 20 mm.

Length 38, height 22, diam. 17 mm.

Coosa River drainage, Georgia and Alabama.

Type locality, Coosawattee River, Murray Co., Ga.

Unio hanleyanus Lea, Tr. Am. Phil. Soc., X, 1852, p. 279, pl.
XXIII, fig. 37; Obs., V, 1852, p. 35, pl. xxi, fig. 37.REEvE,
Conch. Icon., XVI, 1864, pl. xvut, fig. 76—Sowerey, Conch.
feony OVE, - 1866. pl. svi, fig. 240.

Margaron (Unio) hanleyanus Lea, Syn., 1852, p. 26; 1870,
p. 40.

Pleurobema hanleyana SiMPSON, Syn., 1900, p. 759.

This species is close to ?. johannis but the latter seems to
constantly differ in the texture and color of the epidermis.
P. hanleyanum is never clouded nor marked with green, it is
more cloth-like and has the dark rest marks in all cases. It is
a solider, darker colored species than flazidulum.

PLEUROLEMA FLAVIDULUM (Lea).

_ Shell subelliptical, convex or subinflated, inequilateral, rath-
er thin to subsolid; beaks moderately full and elevated; pos-
terior ridge well developed, narrowly rounded, ending in a
point at the median line; epidermis dirty yellow, tawny or
dirty greenish, sometimes with one or two rays on the poste-
rior slope; pseudocardinals subcompressed, two in the left
valve, and one to three in the right ; two delicate laterals in the
left valve and one in the right; beak cavities shallow ; muscle
scars scarcely impressed; nacre whitish or purplish, a little
thinner and iridescent behind.

Length 37, height 21, diam. 15 mm.

Type locality, Columbus, Mississippi.

Unio: fazvidulus Warns, Pr: Ac’ N. Sei. Phila. V, 1861, p. 39;
{iA N. Set.Phila., V, 1862; p.o77: pl. xv; fig. 245 ; Obsi,
VIII, 1862, p. tor, pl. xv, fig. 245.

Margaron (Unio) flavidulus Lua, Syn., 1870, p. 40.

Pleurobema flavidulus Simpson, Syn., 1900, p. 759.

More delicate, thinner and less compressed than either jolan-
nis or hanleyanum. It is sometimes flushed a little with green.

“J
ee)
i)

PLEUROBEMA

Group of Pleurobema bulbosum.

Sheil elongate oval, solid, inflated, with a high posterior
ridge, ending in a point behind, above which it is feebly wrin-
kled; beaks full, sculpture not seen; epidermis smooth, dark,
rayless; hinge strong; pseudocardinals heavy, torn, sometimes
a small third one in the left valve; laterals heavy, club-shaped,
granulate, two in the left valve and one and a small secondary
lateral in the right. Animal unknown.

PI#ZUROLEMA BULBOSUM (Lea).

Shell irregularly ovate or subelliptical, inequilateral, moder-
ately solid; beaks high and full; posterior ridge high, suban-
gular above, narrowly rounded below, ending in a point on
the median line; dorsal slope somewhat truncated and wrin-
kled; surface with irregular growth lines; epidermis black,
subshining ; pseudocardinals small, rough, two in the left valve
and one to three in the right ; laterals two in the left valve and
a decidedly double one in the right; beak cavities shallow ;
muscle scars small; nacre whitish, purplish or salmon-colored.

Length 47, height, 31, diam. 20 mm.

Length 45, height 29, diam. 20 mm.

Ocmulgee and Flint rivers, Georgia.

Type locality, Flint River, Macon, Ga.

Unio bulbosus Lea, Pr Ac N. Sei) Phila 1X) 1857.0p. 2172.
jk Ac NS Ser Phula.. 1V5 1850> p. roi. placa nesace Ons.
Wil, 1850, De 0. ph xxi noms

Margaron (Unio) buibosus Les, Syn., 1870, p. 40.

Pleurobema bulbosa SIMPSON, Syn., 1900, p. 759.

This group is quite different from any other of the genus
Pleurobema and | am not positive as to its relationships, though
the general form, small muscle scars and double lateral of the
right valve incline me to place it here. The truncation of the
post-dorsal slope, and its wrinkles, together with the black epi-
dermis are peculiar characters.

PIEUROREMA HARPERI (B. H. WricH’r).

Shell oval, subinflated, subsolid, inequilateral ; beaks full and
high; posterior ridge angled above, double below, ending in a
biangulation at and below the median line; anterior end some-

PLEUROBEMA 783

what squarely truncated; base line slightly curved, outline of
dorsal slope curved; surface irregularly, concentrically striate ;
epidermis black, strongly, concentrically wrinkled around the
border of the shell, nearly smooth and shining below the um-
bonal region; pseudocardinals two in the left valve and three
in the right; laterals straight, two in the left valve and one in
the right; beak cavities shallow; muscle scars small; nacre
reddish flesh-color.

Length 50, height 30, diam. 20 mm.

Type locality, Altamaha and Flint rivers, Georgia ; Suwanee
River, Florida.

Unio harperi B. H. Wricut, Naut., XIII, 1899, p. 6.
Plewrobema harperi Simpson, Pr. Ac. N. Sci. Phila., 1900, p.

Sr pl. fs. LO; Syl. OOO, ‘p.-750.

I strongly suspect that this is a mere form of P. bulbosum,
but I have only seen a very limited amount of material and
cannot be certain. This differs from that species, so far as
the material I have seen indicates, in being squarely truncate
in front, in being more wedge-shaped when viewed from above,
in having the lateral of the left valve single, and the epidermis
around the border of the shell more rough. But specimens of
bulbosum differ so much that these characters may be only in-
dividual.

PLEUROBEMA RECLUSUM (B. H. Wright).

Shell irregularly ovate, inequilateral, subinflated, rather sol-
id; beaks moderately full and high; their sculpture apparently
a few strong, irregular ridges that curve up behind; posterior
ridge strong, subangular, ending below the median line in a
point ; base line rounded: anterior end subtruncated ; outline of
the dorsal slope curved; surface nearly smooth; dorsal area
with a few plications; epidermis greenish-brown, smooth and
shining; left valve with two ragged pseudocardinals and two
laterals; right valve with one pseudocardinal and a double lat-
eral; beak cavities shallow; muscle scars small, impressed;
nacre brilliant silvery, bluish-tinted, iridescent and thinner be-
hind.

Length 4o, height 25, diam. 17 mm.

Type locality, Ochlocknee River, Leon County, Florida.
Umo reclusus B. H. Wricut, Naut., XI, 1808, p. 3.

784 PT,EUROBEMA

Pleurobema reclusa Stmpson, Pr. Ac. N. Sci. Phila., 1900, p
82, pl. 1, fig. 2; Syn., 1900, p. 760.
Close to bilbosum. It is not so inflated as that species, its
beaks are not so full, the dorsal slope is more plicate, the epi-
dermis is greener, and the nacre is different.

Group of Pleurobema brumbyanum.

Shell oval, inflated, moderately solid, faintly swollen at post-
basal region; beaks rather prominent, somewhat distant from
the anterior end; beak sculpture not seen; disks irregularly,
concentrically sculptured; epidermis dark olive to blackish,
striate; pseudocardinals subradiate, slightly compressed; lat-
eral of the right valve nearly or quite single; beak cavities

shallow; nacre iridescent posteriorly, somewhat thickened in
front.

PLEUROBEMA BRUMBYANUM (Lea).

Shell almost evenly elliptical, subinflated to inflated, sub-
solid, inequilateral ; beaks somewhat elevated and inflated ; pos-
terior ridge well developed, narrowly rounded or subangular,
ending behind in a blunt point at the median line ; anterior end
rounded ; base line curved, sometimes a little fuller just behind
the middle: outline of dorsal slope curved, elevated at the
hinder end of the ligament almost into an angle; surface un-
evenly -and somewhat feebly concentrically sculptured, the
sculpture strongest on the dorsal slope; epidermis greenish-
brown to blackish, rather smooth, subshining ; pseudocardinals
slightly subcompressed, two in the left valve and one in the
right; two delicate laterals in the left valve and one in the
right; muscle scars rather shallow; beak cavities not deep;
nacre whitish, a little thicker in front.

Length 52, height 34, diam. 22 mm.

Length 47, height 30, diam. 22 mm.

Alabama River system.

Type locality, Warrior River, Tuscaloosa, Ala.

Unio brumleyanus Lea, Proc. Am. Phil. Soc., II, 1841, p. 82.
Unio brumbyanus Lea, Tr. Am. Phil Soc., VIII, 1842, p. 245,
pl. xxvi, fig.c62;Obs., ITT, 1842) p--8a; pla xxv, fies Gat

PLEUROBEMA 785

Margaron (Unio) brumbyanus Lea, Syn., 1852, p. 31; 1870,
Pp: 49.

Pleurobema brumbyana SiMPson, Syn., 1900. p. 760.

Umo concolor Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 40; Jl.
Nee Ne oC Auld. Wj. 1o02, p. 89; pl. xis, ne. 237; Obs., VIII,
1862, p. 93, pl. x11, fig. 237.—-SowrErRBy, Conch. Icon., XVI,
1868, pl. LXxxil, fig. 440.

Margaron (Unio) concolor Lwa, Syn., 1870, p. 49.

Less inflated, thinner, smoother and more strongly concen-
trical!y sculptured than P. pinkstoni. I have given above the
measurements of the types of Lea’s Unio concolor and brum-
byanus. ‘The latter is a little smaller, a little more inflated and
a trifle darker than concolor, but I believe they are both one
species.

PLEUROBEMA PINKSTONI (S. H. Wright).

Shell almost regularly oval, inflated. subsolid, somewhat in-
equilateral; beaks full, only moderately elevated; posterior
ridge rather low, rcunded, the disk in front being much more
inflated; surface with irregular growth lines; epidermis dark
brownish or blackish, irregularly, concentrically wrinkled, of-
ten showing the rest marks, dull; left valve with two triangu-
lar, radial pseudocardinals and two delicate, slightly curved
laterals; right valve with one pseudocardinal, sometimes with
vestigial ones, and one lateral; muscle scars impressed; beak
cavities not deep; nacre bluish-white, thicker in front, 1rides-
cent behind.

Length 58, height 35. diam. 30 mm.

Alabama River system.

Type locality, Tallapoosa River (not Tuscaloosa), Macon
Co., Ala.

Unio pinkstoni S. H. Wricu7, Nautilus, X, 1897, p. 136.
Pleurobema pinkstoni Stmrson, Pr. Ac. N. Sci. Phila., p. 81,

pl i, fic. 8; Sym, 1900; p. 758:

Since writing the Synopsis I have seen additional material
of this species and am inclined to place it near P. brumbyanum
rather than in the troschelianum group. In fact it 1s close to

786 PIL.KUROBEMA

that species, but has a duller, more brownish epidermis, which
sometimes shows the rest periods quite plainly. It is also more
inflated and a little solider than that shell.

Group of Pleurobema argenteum.

Shell solid, oval to rhomboid, generally compressed, with
high but not inflated beaks, well removed from the anterior
end, which have strong, irregular sculpture, curved up and
swollen behind where the bars are slightly looped; epidermis
brownish to straw-color, sometimes having a few broken,
blotched rays; teeth strong; cicatrices deep and distinct. Ani-
mal unknown.

PLEUROBEMA SIMULANS (Lea).

Shell somewhat rhomboid, subcompressed, inequilateral, sub-
solid ; beaks moderately full and high; posterior ridge well de-
veloped, narrowly rounded, ending in a blunt point near the
base of the shell; anterior end rounded; base line lightly
curved; outline of the dorsal slope curved and raised into an
angle behind the ligament, surface rather smooth; epidermis
brownish-green or greenish-brown, sometimes faintly rayed
or clouded with yellow ; left valve with two triangular pseudo-
cardinals and two curved laterals; right valve with one pseudo-
cardinal and vestiges of one or two others, with one double
lateral; beak cavities not deep; muscle scars small; nacre blu-
ish-white, thinner and very iridescent behind.

Length 40, height 25, diam. 15 mm.

Black Warrior and Cahawba rivers, Alabama; Pine Barren
Creek, Escambia County, Florida.

Type locality, Cahawba River, Shelby Co., Ala.

Unio simulans Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 190; Jl.
Ac, N, ‘Sei: Phila., VIE, 1874; p. 18;/plk vo ne aS Obes
DUD ie Zea. 22 0p le Vvestionmse

Pleurobema simulans Stmpson, Syn., 1900, p. 760.

This species is close to P. patsaligense, but is more elon-
gated, is darker colored and has a rather higher posterior
ridge. Some specimens appear almost black. It is much
shorter than P. strodeanum, and is not black like that species.

PLEUROREMA 787

PLEUROBEMA UTRICULUM (Lea).

Shell almost elliptical. subinflated or convex, inequilateral,
rather solid; beaks full and high; anterior end narrowed and
rounded; base line curved; posterior end obliquely subtrun-
cated; posterior ridge full, rounded, ending near the base in
a feeble biangulation; epidermis greenish-brown, showing
faint, dark rest marks; pseudocardinals small, triangular, two
in the left valve and one in the right; laterals two in the left
valve and one in the right ; beak cavities shallow ; nacre bluish-
white, thinner and iridescent behind.

Length 43, height 30, diam. 19 mm.

Type localitv, North Carolina.

Unio uiriculus Lea, Pr. Am. Phil. Soc., TV, 1845, p. 164; Tr.
Am Phils Soe., ©, 1848 ip- 69, pl. a, fig. 3; Obs., 1V, 1848,
pe 4g; pl i figs 3:

Margaron (Unio) utriculus Lea, Syn., 1870, p. 46.

Ouadrula utriculus SIMPSON, Syn., 1900, p. 785.

In the Synopsis I placed this species in Quadrula with a
question. [ am inclined on giving it additional study to place
it in Pleurobema near simulans. Its beak cavities are shallow ;
the pseudocardinals are small and not split up. Lea has two
shells placed with the type of wtriculus, said to come from Ar-
kansas, which do not seem to me to be that at all, but are prob-
ably undescribed. They are so badly worn that I do not think
it advisable to give diagnosis of them.

PLEUROBEMA STRODKFANUM (B. H. Wright).

Shell irregularly short elliptical, subcompressed, scarcely
subsolid, slightly inequilateral ; beaks moderately full and high;
posterior ridge well developed, subangulate, ending in a point
below the median line; anterior end round; base line rounded ;
outline of dorsal slope almost evenly curved; epidermis closely,
concentrically striate, cloth-like on the border, shining at the
umbonal region, nearly jet black; left valve with two pseudo-
cardinals and two nearly straight laterals ; right valve with one
pseudocardinal and a double laterai; beak cavities not deep*

788 PLEUROBEMA

muscle scars small, shallow; nacre bluish-white, thinner and
iridescent behind.

Length 37, height 28, diam. 16 mm.

Type locality, Escambia River, Florida. Also, Flint River.
Rhoadsville, Georgia.

Umo strodeanus B. H. Wricut, Naut., XII, 1808, p. 5.
Pleurobema strodeana Stmpson, Pr. Ac. N. Sci. Phila., 1900,

p: 81, plot, hig. 35 Syn, 1900, pp. 7ole

The type, whose dimensions are given above, may be a young
shell. Its short, nearly elliptical form and black epidermis
together with the almost blue nacre distinguish it from allied
species.

PLEUROBEMA PATSALIGENSE Simpson.

Shell nearly elliptical or subrhomboid, convex or subinflated,
scarcely subsolid, inequilateral; beaks moderately full and
high ; posterior ridge subangular or narrowly rounded, ending
in a point or slight biangulation below the median line; sur-
face finely and unevenly concentrically sculptured; epidermis
tawny-green flushed with brown at the umbonal region and
generally faintly rayed, rather dull and cloth-like, sometimes
slightly blistered; pseudocardinals two in the left valve and
one to three in the right; left valve with two laterals; right
valve with one; beak cavities not deep; muscle scars small;
nacre dirty whitish, sometimes tinted purple and blotched.

Length 45, height 33, diam. 18 mm.

Length 43, height 25, diam. 17 mm.

Type locality, Little Patsaliga Creek, Crenshaw Co., Ala-
bama.

Pleurobema patsaligensis Stimpson, Pr. Ac. N. Sci. Phila.,

1900; p. 82, pl. 11, fig: 1; Syn. 1960; Pp. 70m:

Thinner and generally shorter than P. simulans, usually
lighter colored and having duller nacre.

PLEUROBEMA STRIATULUM (Lea).

Shell short, subrhomboid, subsolid or solid, convex or sub-
inflated, slightly inequilateral ; base somewhat rounded; beaks
full and high, their sculpture consisting of ridges which are

PLEUROBEMA 789

curved up behind; posterior ridge high, angled, ending behind

in a point near the base; dorsal slope obliquely truncated,

meeting the dorsal line at an angle; epidermis greenish-brown ;
left valve with two low, rough, rather solid pseudocardinals
and two short, straight laterals; right valve with one pseudo-
cardinal and one lateral, the latter inclined to be double ; mus-
cle scars small, shallow ; beak cavities compressed ; nacre whit-
ish, iridescent behind.

Length 40, height 28, diam. 17 mm.

Type locality, Roanoke River, Weldon; also Salem, North

Carolina.

Umo striatulus Lea, Pr. Acad. N. Sci. Phila., I, 1857, p. 86;
ie Necad Ne Set. (Phila. V_.1862, p-.55; pl. 1, fig..202,; Obs.,
VIII, 1862, p. 59, pl. 1, fig. 202.—Sowerpy, Conch. Icon.,
XVI, 1868, pl. Lxxu, fig. 367——SIMPSON, Syn., 1900, p. 719.

Margaron (Unio) striatulus La&a, Syn., 1870, p. 37.
Conchologically this and a few other apparently related spe-

cies seem closely allied to the Unio argenteus of Lea, and I am

now inclined to place them in that assemblage notwithstanding
the fact that they are found in the Atlantic drainage. The
beak sculpture of these forms, so far as I can ascertain, is rath-
er strong ridges which turn up sharply behind and this style of
sculpture is more characteristic of Plewrobema than of Unio.

Their peculiar distribution is no more remarkable than that of

Lampsilis constricta, which is found in both the Atlantic and

Tennessee areas.

PLEUROBEMA FAVOSUM (I[,ea).

Shell subrhomboid, subcompressed or convex, subsolid, in-
equilateral; beaks rather full and high, their sculpture a few
irregular corrugations; posterior ridge narrowly rounded, end-
ing in a blunt point near the base of the shell; anterior end
rounded ; base evenly curved; dorsal line nearly straight, meet-
ing the obliquely truncated posterior slope with an angle; sur-
face delicately, concentrically striate; epidermis yellowish-
green or brownish, generally with a broad, ill-defined, broken
ray in front of the posterior ridge ; pseudocardinals two in the

790 PLEUROBEMA

left valve and one in the right; left valve with two laterals :

right valve with a somewhat double one; beak cavities not

deep; muscle scars small, shallow; nacre whitish, thinner and
iridescent behind.

Length 50, height 33, diam. 18 mm.

Alabama River system.

Type locality, Othcalooga Creek, Gordon Co., Ga.

Umio favosus les, Proc. Ac. N. Sci. Phila., VIII, 1856, p. 262;
jl. Ac.ON. Sci. Phila:; TV 1858) pe 58. pliavan, ties yom Oboe
VI, p. 58, pl. vir, fig. 40-—SowkERBy, Conch. Icon., XVI,
1868, pl. xc, fig. 488.

Margaron (Unio) favosus Lea, Syn., 1870, p 38.

Pleurobema favosa SIMPSON, Syn., 1900, p. 76T.

The shell approaches that of several species, simulans, ar-
genteum, amabile and patsaligense, etc. It is larger and light-
er colored than simulans, smaller, brighter colored and more
curved on the base than argenteum, larger, more compressed,
and greener than amabile, thinner and more rounded below
than pyriforme, more elongated than patsaligense and does
not have fine rays. It must be confessed that many of the
forms I have placed in this group are close and puzzling, that
a good many specimens are found that cannot be referred with
certainty to anything. The types of all these species are dis-
tinct enough and I have not felt that the material I have seen
would justify me in uniting them. The base is sometimes
swollen just behind the middle.

PLEUROBEMA LENTICULARE (Lea).

Shell between subtriangular and subrhomboid, subcompress-
ed, rather solid, somewhat inequilateral; beaks apparently not
very full or high; posterior ridge rather low, slightly double,
ending below the median line in a biangulation; anterior end
faintly and obliquely truncate above, rounded below; base line
lightly curved; outline of dorsal slope curved; epidermis close-
ly, concentrically wrinkled, brownish, showing feeble rest
marks; left valve with two triangular pseudocardinals and
two curved laterals; right valve with three pseudocardinals,

PILEUROBEMA 791

the anterior and posterior ones feeble, and a double lateral ;

beak cavities shallow; muscle scars small, impressed; nacre

lurid purple; iridescent and thinner behind.

Length 44, height 33, diam. 16 mm.

Type locality, Tellico River, Monroe County, Tennessee.
Also, East ‘Tennessee.

Unio lenticularis Lma, Pr. Acad. N. Sci. Phila., II, 1872, p.
i557 Jl Acad: N. Se: Phila, Vill, 1874, p: 30, pl. 1x, fig.
27; Obs., XIII, 1874, p. 34, pl. 1x, fig. 27—Simpson, Syn.,
1900, p. 761.

A very rare species. A small shell, which Lea has placed
with this, is, I think, a P. barnesianum, and another is possibly
a P. meredithti in bad condition. The species is close to the
latter and may merge into it. The type is rather dark brown,
and the nacre is a peculiar lurid purple tint.

PLEUROBEMA MEREDITHI! (Lea).

Shell subovate or subrhomboid, lenticular, subsolid, inequi-
lateral; beaks little elevated or inflated; posterior ridge well
developed, inclined to be narrowly double, ending below the
median line in a feeble biangulation; anterior end round; base
line curved; outline of dorsal slope curved, elevated just be-
hind the ligament; surface with irregular, concentric sculp-
ture; epidermis finely, concentrically wrinkled, greenish-yel-
low or brownish, dull; left valve with two pseudocardinals and
two curved laterals; right valve with one to three pseudocard1-
nals and a double lateral; beak cavities not deep; muscle scars
small, impressed; nacre silvery white or flesh-colored.

Length 45, height 36, diam. 18 mm.

Tennessee River system; Black Warrior River, Alabama.

Type locality, Tennessee River, Tuscumbia, Ala.

Unio meredithn Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 40;
tieAcy Na Ses, (Phila. 7V , 1862, p: 65, ple vi, fig: 2145" Obs:,
VIII, 1862; p. 69, pl. vi, fig. 214.

Margaron (Unio) meredithti Lax, Syn., 1870, p. 35.

Pleurobema meredithti Stimpson, Syn., 1900, p. 76.

792 PLEUROBEMA

The shell is lighter colored than P. lenticulare, it is wider
and more rounded anteriorly and is much lighter colored with-
in and without, but it is quite likely only a variety of that
species.

PLEUROBEMA LITUM (Lea).

Shell subrhomboid, convex, subsolid, somewhat inequilat-
eral; beaks only moderately developed; posterior ridge rather
strong, narrowly rounded, ending in a blunt point near the
base of the shell; anterior end rounded ; base curved ; posterior
end obliquely truncated ; surface with irregular growth lines;
epidermis straw-color to tawny, finely, concentrically wrinkled,
shining, showing the dark rest marks; pseudocardinals two
in the left valve and one and an anterior rudimentary one in
the right; two laterals in the left valve and one in the right ;
beak cavities shallow; muscle scars small, not deep; nacre
brilliant salmon or reddish, iridescent and thinner behind.

Length 41, height 26, diam. 15 mm.

Cahawba and Black Warrior rivers, Alabama.

Type locality, Cahawba River, Shelby Co., Ala.

Unio ltus ea, Pr AGN. Sei.Phila., | 1871) p. mao. ie ne.
N.. Sct Philas VII ae74p. 17, pi wv. ne anes Oliere alien
10745 pi 2ic Pile Vhs AT se

Pleurobema lita Simpson, Syn., 1900, p. 761.

I am not positive as to where this form should be placed.
There are only two shells in the Lea collection, the larger, of
which I have given measurements, may be adult, the other is
a young shell. The rich, bright epidermis with its dark rest
marks and the brilliant nacre are good characters.

PLEUROREMA GEORGIANUM (Lea).

Shell subrhomboid, slightly obovate, being narrower at the
anterior end, convex, subsolid, somewhat inequilateral; beaks
apparently not very full or high; posterior ridge narrowly
rounded, ending below the median line in a blunt point; an-
terior end rounded; base line curved; posterior end obliquely
subtruncate, joining the dorsal line with an angle; epidermis

PILEUROBEMA 793

dull, dirty tawny with a tint of green, showing faint rest

marks; pseudocardinals triangular, nearly smooth, two in the

left valve and one in the right; laterals two in the left valve
and a double one in the right: muscle scars shallow ; beak ecav-
ities not impressed; nacre pale dirty violet, thinner behind.

Length 40, height 28, diam. 16 mm.

Type locality, Stump Creek, northwest Georgia.

Unio georgianus Lita, i, Aim. Phil s0¢. "bE tear, py ar 5s.
Am. Phil. Soc., VIII, 22). 235, pl. xx. hie. 4g Obs. TIT.
1542. Pp. AZ. pl -XXE, ee 49.—CHENU, Ill. Conch., 1858, pl.
ARE, WIS, 3, 3a). 30:

Margaron (Unio) georgianus Lea, Syn., 1852, p. 27; 1870,
p. 42.

Pleurobema georgiana SIMPSON, Syn., 1900, p. 761.

I am uncertain as to the position of this species. I have
seen only the type, which is broken and in rather bad condi-
tion. It is a remarkably lenticular form, with a dull, dirty
brownish or greenish-tawny epidermis.

PLEUROBEMA PYRIFORME (Lea)

Shell subelliptical or subrhomboid, subcompressed, solid, in-
equilateral; beaks apparently neither full nor high; posterior
ridge narrowly double, ending above the base line in a bian-
gulation: anterior end rounded; basal and dorsal outlines
curved, the former least so; the outline of the dorsal slope is
sometimes elevated almost into an angle at or behind the liga-
ment; surface finely, concentrically striate; epidermis tawny
or tawny-brown, often shaded or clouded with green; more or
less shining, polished at the umbonal region; hinge rather
strong ; pseudocardinals two in the left valve and one to three
in the right; laterals two in the left valve and one in the
right: beak cavities shallow; muscle scars small, not deep:
nacre salmon, thinner behind.

Length 54, height 33, diam. 17 mm.

Length 52, height 29, diam. 16 mm.

Type locality, near Columbus, Georgia.

794 PLEUROBEMA

Unio pyrifornus Lea; Pro Ac Nasc: Phila x 1857 ps a
Jl, Ac. N.seis PhilagelV ses erp ‘Copii che 50.5 Ose
VI, p60; pl xi, figss5o.

Margaron (Unc) pyriformis Lea, Syn., 1870, p. 40.

Pleurobema pyriformis SIMPSON, Syn., 1900, p. 762.

Close to P. argenteum, but smaller, more nearly elliptical,
with a brighter epidermis and salmon nacre.

PLEUROBEMA AMABILE (Lea).

Shell rather small, subovate, convex, solid, inequilateral ; an-
terior end rounded, base curved; posterior slope obliquely sub-
truncate; posterior ridge high, narrowly rounded, ending be-
hind in a point just below the median line; beaks high and
full, their sculpture a series of strong ridges, running nearly
parallel with the growth lines, but heavier and suddenly turn-
ed up behind; epidermis almost smooth, tawny or tawny-
brownish, subshining, sometimes very feebly rayed; left valve
with two solid, subcompressed, rough pseudocardinals and two
short laterals; right valve with one pseudocardinal and a ves-
tigial tooth in front of and behind it, and one somewhat dou-
ble lateral ; beak cavities shallow but compressed ; muscle scars
small; nacre whitish or straw-colored, iridescent and thinner
behind.

Length 37, height 25, diam. 16 mm.

Type localitv, Butler, Taylor County, Georgia.

Unio amabilis Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 89; Jl.
Ac Ne Sem Phila, Vil, 1869). p:-257, pixxx te) 72 Ops
XII, 1869, p. 17, pl. xxx, fig. 72.—SIMPSON, Syn., 1900, p.
720.

Margaron (Unio) amabilis Lea, Syn., 1870, p. 37.

Apparently close to the Unio pyriformis of Lea and it may
connect with that species. Judging from the type, it is short-
er, smoother and lighter colored than that species and has a
somewhat higher posterior ridge.

PLEUROPEMA MCDICUM (Lea).

Shell small, subrhomboid, inequilateral, convex to subinflat-
ed, subsolid : beaks full and high, sculptured with a few strong
ridges ; posterior ridge rather full, but not distinctly biangulate,

PLEUROLEMA 795:

ending in a blunt point at the base of the shell; anterior end

rounded; base line nearly straight; outline of posterior slope

obliquely truncated ; surface nearly smooth; epidermis brown-
ish-green when young, dirty reddish-brown when old, dull
colored; left valve with two pseudocardinals and two curved
laterals ; right with one pseudocardinal and one, usually double,
lateral; muscle scars shallow; beak cavities not deep; nacre
flesh-colored or purplish, thicker in front.

Length 38, height 22, diam. 17 mm.

Chattahoochee River, Georgia.

Type locality, Columbus, Ga.

Unio ‘cee Eiri oene. IN. Och biitla., PX, 1857, p. 1705
i Ae Ne se Phila -1V, 1850, p. 204, plo xxiv, fig. 86;
Obs., VI, 1800, Pp: 22; pl. XxIv, fig. 86.

Margaron (Unio) medicus Lea, Syn., 1870, p. 40.

Pleurobema modica SiMpson, Syn., 1900, p. 762.

Smaller than P. gibberum, more inflated and having a less
distinctly biangulate posterior ridge. It is duller colored with-
in and without.

PLEUROBEMA STRIATUM (Lea).

Shell small, subrhomboid, subcompressed or compressed,
scarcely subsolid, inequilateral; beaks only moderately full
and high, their sculpture a few strong irregular ridges; pos-
terior ridge rounded or feebly biangulate, ending below the
median line; anterior end rounded; base line curved; outline
of dorsal slope curved, sometimes angular behind the liga-
ment; epidermis decidedly, concentrically wrinkled, dirty
greenish or brownish, somewhat cloth-like; left valve with two
pseudocardinals and two laterals; right valve with one pseudo-
cardinal and a double lateral; beak cavities and muscle scars
shallow ; nacre dirty purplish, iridescent behind.

Length 36, height 23, diam. 13 mm.

Chattahoochee River, Georgia.

Type locality, Columbus, Ga.

Unio striatus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr.
Asn Phil. Socy VILE, 1643) p. 203, pl.ixir) fig. 165; /Obs.,, ITT,
1842, p. 41, pl. xu, fig. 16—CHENu, III. Conch., 1858, pl.
SI ies TG ST:

796 PLEUROBEMA

Margaron (Unio) striatus Lea, Syn., 1852, p. 26; 1870, p. 40.

Pleurobema striata SIMPSON, Syn., 1900, p. 762.

A small. rather thin, compressed species, having the dull
epidermis decidedly, concentrically wrinkled, so that the un-
rubbed shell is cloth-like. There is a good deal of variation in
the development of the posterior ridge.

PLEUROBEMA GIBBERUM (Lea). °
Shell subrhomboid, convex, rather solid, inequilateral ; beaks

moderately elevated and full; posterior ridge double, ending
at the base of the shell; anterior end a little narrowed, round-
ed: base line nearly or quite straight; outline of dorsal slope
lightly curved; surface with delicate, uneven, concentric sculp-
ture; epidermis reddish-brown, subshining; left valve with
two pseudocardinals and two laterals; right valve with three
pseudocardinals and one lateral; muscle scars not deep; beak
cavities shallow ; nacre bronzy or coppery-purple, thin and iri-
descent behind.

Length 45, height 26, diam. 14 mm.

Type locality, Caney Fork River, Tennessee.

Unio gibber Lea, Tr. Am. Phil. Soc., VI, 1838, p. 34, pl. x,
fig. 30; Obs., II, 1838, p. 35, pl. x, fig. 30—HANLEy, Biv.
Shells, 1843, p. 185, pl. xx1, fig. 46—CueENu, Il. Conch.,
1858, pl. Xxi1!, figs. 2, 2a, 2b.--Sowerpy, Conch. Icon., XVI.
1866, pl XE, fey 210!

Margarita (Unio) gibber Laas, Syn., 1836, p. 20; 1838, p. 17.

Margaron (Unio) gtbber Lea, Syn., 1852, p. 24; 1870, p. 37-

Pleurobema gibber Stimpson, Syn., 1900, p. 762.

Close to pyriforme and modicum. Smaller and more trt-
angular in outline than the former: larger, less inflated and
having a more distinctly biangulate posterior ridge than the
latter.

PLEUROBEMA RAVENELIANUM (lea).

Shell -subovate or subrhomboid, subinflated, inequilateral,
solid; anterior end rounded; base lightly curved or straight ;
post-dorsal line curved or obliquely subtruncated ; beaks full,
moderately high; posterior ridge well developed, rounded,

PLEUROREMA 797

rarely slightly biangulate, ending near the base of the shell
in a blunt point or feeble biangulation ; epidermis concentric-
ally wrinkled, dull, greenish-brown, or yellowish-brown, ray-
less or with faint, broken rays; pseudocardinals low, stumpy,
two in the left valve and one with vestiges of two others in
the right ; laterals two in the left valve and a somewhat double
one in the right; beak cavities shallow; muscle scars small,
deep; nacre white or lurid whitish.

Length of type 37, height 24, diam. 16 mm.

Length 52, height 35, diam. 21 mm.

Length 50, height 36, diam. 25 mm.

Kentucky ; Tennessee; western North Carolina.

Type locality, French Broad River, Asheville, N. C.

Unio ravenelianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 32, pl.
ur, fig. 5; Obs., I, 1834, p. 144, pl. 11, fig. 5 —HaNn_ey, Biv.
Shells, 1843, p. 187, pl. xx, fig. 59—Kuster, Conch. Cab.
Unio, 1862, p. 269, pl. xcr, fig. 1—Rkreve, Conch. Icon.,
XVI, 1864, pl. xvr, fig. 70.

Margarita (Unio) ravenelianus Lea, Syn., 1836, p. 22; 1838,
pe ie:

Margaron (Unio) ravenelianus Lea, Syn., 1852, p. 26; 1870,
p. 40.

Pleurobema raveneliana SIMPSON, Syn., 1900, p. 748.

Unio decisus Kusier, (part) Conch. Cab. Unio, 1852, p. 41,
pl. viii, fig. 1.

I placed this in the group of Pleurobema clava in the Synop-
sis with considerable doubt. It is an aberrant form having
some of the characters of the argentewm group, but is quite
solid and inflated for that assemblage. I now place it near
P. modica with some hesitation. It is larger and rather more
inflated than that species and is considerably solider and much
more inflated than P. pyriforme.

PLEUROREMA FASSINANS (Lea).

Shell subelliptical or subrhomboid, convex, rather solid, 1n-
equilateral; beaks high but not full; posterior ridge well de-
veloped, inclined to be double, ending in a feeble biangulation
below the median line; anterior end rounded; base line wel!

798 PLEUROBEMA

curved; outline of dorsal slope curved, elevated to a low angle

behind the ligament: surface rudely, concentrically striate;

epidermis concentrically wrinkled, reddish-brown, not shining ;
left valve with two pseudocardinals and two laterals; right
valve with two pseudocardinals and a double lateral; muscle
scars impressed ; beak cavities not deep; nacre lurid flesh-color,
shining, thinner behind.

length 60, height 40, diam. 22 mm.

Upper Tennessee River drainage.

Type locality, Headwaters of the Holston River, Washing-
ton Co., Va.

Unio fassinans Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 143;
fl.-Acl ON. Ser Phila, Vil 860; p) 305s) pl.) sive.
Obs) Xl p65, pl xvi, fee:

Margaron (Unio) fassinans LEA, Syn., 1870, p. 42.

Pleurobema fassinans SIMPSON, Syn., 1900, p. 762.

Close to several forms of this puzzling group. It is more
evenly elliptical than argentewm and has a darker epidermis.

Var. rhomboideum Simpson.

Shell considerably more rhomboid than the type.

Type locality, Upper waters of the Clinch River, Virginia.
Pleurobema fassinans var. rhomboidea SIMPSON, Syn., 1900,

[Dn AOS

A form occurs in this region, which has most of the char-
acters of fassimans, but is more rhomboid. It may be a dis-
tinct species but I do not feel like adding another specific
name to this terribly difficult group without the very best of
reasons.

PLEUROBEMA ARGENTEUM (Lea).

Shell subrhomboid or subovate, compressed or subcompress-
ed, rather solid, inequilateral; beaks not very full or high;
posterior ridge single or double, ending in a point or biangula-
tion near the base line; anterior end rounded; base line
curved; outline of dorsal slope raised to an angle behind the
ligament, the posterior end being obliquely truncated ; surface
with fine, uneven, concentric sculpture; epidermis dull green-

PLEUROBEMA 799

ish, dull brownish or somewhat tawny, often showing rest
marks, not shining; pseudocardinals low, ragged, two in the
left valve and one to three in the right ; laterals two in the left
valve and one in the right ; muscle scars impressed ; beak cavi-
ties not deep; nacre whitish, often silvery, thinner and irides-
cent behind.

Length 63, height 39, diam. 20 mm.

Upper Tennessee River drainage.

Type locality, Holston River, Tenn.

Ujiorarcenteus eA, Pr. Am. Phil. Soc., II, 1841, p. 82; Tr.
Eiken Soc, .V ll 184% p. 242,pl. xxv, fig. 57; lise EE
1842, p. 80, pl. xxv, fig. 57—CueEnu, III. Conch., 1858, pl..
ROME HOS, 2. Sa, 2b—Kus'rer, Ganch Cab. Unio, 1861,
p- 188, pl. Lrx, fig. 4; 1861, p. 225, pl. Lx xvi, fig. 3—SowEr-
BY, Conch. Icon., XVI, 1868, pl. xxxvit, fig. 204.

Margaron (Unio) argenteus LEA, Syn., 1852, p. 26; 1870, p. 40.

Pleurobema argentea SIMPSON, Syn., 1900, p. 763.

The type differs somewhat from any shells I have seen,
being more ovate in outline and having a smoother, greener
epidermis than other shells, which Dr. Lea refers to the species.
The shel! is larger than pyriforme and lacks the almost coppery
luster of that form. It is not so rhomboid as flanius or
estabrookianum and lacks the strong, concentric sulcations that
characterize them. It is near to breve and I am not sure but
what some of the material referred to argenteum should be
placed in that species. The former has a higher posterior
ridge and is more distinctly rhomboid.

Var. pannosium Simpson.

Shell more rude and solid than the type, the surface being
roughly concentrically sculptured; epidermis coarse, brownish
or tawny-brown, dull colored; nacre thick in front, suddenly
becoming thinner.

Length 75, height 47, diam. 26 mm.

Type locality, Hot Springs, Arkansas.

Pleurobema argentea pannosa Stmpson, Pr. Ac. N. Sci. Phila

1900, p. 82; Syn., 1900, p. 763.

800. PLEUROBEMA

This may be a distinct species, but I do not feel like separat-
ing it on the limited amount of material I have seen. The
surface is quite dull and rude; the anterior basal part of the
nacre is quite solid, becoming suddenly thinner at the cavity
of the shell.

PLEUROBEMA CONASAUGENSE (Lea).

Shell long rhomboid, solid, subinflated, inequilateral ; beaks
moderately full and high; posterior ridge well developed,
somewhat double, ending behind in a biangulation near the
base of the shell; anterior end rounded; base line nearly
straight ; posterior end obliquely truncated above; the trunca-
tion joining the slightly curved dorsal line at an angle; sur-
face with irregular growth lines; epidermis dark tawny or
brownish, concentrically wrinkled, almost cloth-like; left valve
with two triangular pseudocardinals and two short, curved
laterals; right valve with one pseudocardinal and two rudi-
mentary ones, with a double lateral; beak cavities not deep;
muscle scars well impressed; nacre soiled whitish.

Length 65, height 40, diam. 26 mm.

Upper Tennessee River drainage. '

Type locality, Conasauga Creek, Monroe Co., Tenn.

Unio conasaugaensis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p.
r553 Jin Ace, No se Phila Vu e743, pLisees 40.
Obs), XT 18745 p27,eple ype 30:

Pleurobema conasaugaensis SIMPSON, Syn., 1900, p. 763.

A subinflated, rather solid species, which is close to P. breve.
It is a little more inflated, heavier and more elongated than
that species. The form from Hardy, Arkansas, which I called
variety subelliptica of breve might as well be considered a
variety of conasaugense as specimens seem to almost connect
the two.

PLEURORRMA BREVE (Lea).

Shell rhomboid or somewhat subtriangular, compressed or
subcompressed, rather solid, somewhat inequilateral; beaks
apparently only moderately full or high; posterior ridge strong,
narrowly and feebly double, ending in a biangulation at the

PLEUROREMA Sor

base of the shell; anterior end somewhat slopingly truncate
above, rounded below; dorsal slope obliquely truncate, angled
at the hinder end of the ligament; base line nearly straight ;
epidermis tawny, sometimes showing rest marks, concentrically
wrinkled and dull, rarely faintly rayed; pseudocardinals two
in the left valve, one to three in the right; left valve with two
laterals; right valve with a somewhat double one; beak cavi-
ties not deep; muscle scars small, slightly impressed; nacre
whitish or purplish tinted, thinner behind.

Length 50, height 35, diam. 18 mm.

‘Tennessee River system.

Type locality, Conasauga Creek, Monroe Co., Tenn.
Unagrbrenis Wea Pr Aco N. Sc. Phila., 11; 1872,'p. 157; Jl.

AeeN.eoei Philas VIE, 21874; p: 35; pl- xi), fig. “32°; Obs.,

REET 7AG p> 36, pl-cxin fist.42.

Pleurobema brezis SIMPSON, Syn., 1900, p. 763.

This has a higher posterior ridge than P. argenteuwm, and the
shell is usually most inflated along that line, being often wedge-
shaped in front, when viewed from above. But there are
intermediates that cannot be placed with certainty in either
species.

Var. subellipticum Simpson.

Shell larger and more elongated and inflated than the type;
posterior ridge decidedly double.
Type locality, Hardy, Arkansas.
Pleurobema brevis subelliptica Simpson, Pr. Ac. N. Sci. Phila.,
TgOO, p. 8o.
Pleurobema brevis var. subilliptica Stmpson, Syn., 1900, p.
763.
This may be a valid species, but there are specimens, which
seem to be intermediate between the two. By a typographical
error this name was spelled subilliptica in the Synopsis.

PLEUROBEMA MISSOURIENSE Marsh.

“Shell smooth, obliquely triangular, rounded before, sub-
triangular behind, moderately thick, very much thicker ante-
riorlv, sides somewhat flattened; beaks wide, solid, incurved:

802 PLEUROBEMA

ligament long, light brown; epidermis light brown, without
rays; growth lines numerous, not raised; umbonal slope wide
and rather flat; posterior slope wide, flattened, with two dark,
inconspicuous lines running from beaks to posterior margin;
beak sculpture unknown; cardinal teeth rather long and solid,
depressed, disposed to be double in both valves, corrugate;
lateral teeth straight, oblique, corrugate; anterior cicatrices
distinct, deep ; posterior cicatrices distinct and well impressed ;
shell cavity wide and deep; nacre white.” (Marsh).

(Dimensions not given. )

Type locality, Black River, Poplar Bluff, Butler Co., Mo.
Pleurobema missouriensis MArsH, Naut., XV, 1gol, p. 74.

“T know of no described species, which this closely resem-
bles; in outline tt is perhaps nearest to U. bigbyensis Lea, but
differs in every other respect. Specimens of bigbyensis from
Flint River, Ala., attain twice the size of this shell. Bigbyen-
sis is nearly always covered with green rays. This shell is ray-
less. It also has higher and more massive beaks, 1s more
equilateral and differs entirely in the color of epidermis, teeth,
etc. The color of the epidermis and the character of the beaks
is more like U. hartmanianus Lea, but that shell has very much
higher beaks, more swollen and pointed, and is in every respect
a more solid shell.”

PLEUROBEMA PLANIUS (Lea).

Shell decidedly rhomboid, subcompressed, subsolid, inequi-
lateral ; beaks apparently not very full or high; posterior ridge
double, ending below in a rather wide biangulation at the base
of the shell; above the posterior ridge there is a shallow, radial
depression ; anterior end rounded; base line straight ; posterior
end obliquely truncated; surface feebly concentrically sculp-
tured; epidermis greenish-yellow, tawny behind, with a few
broken green rays, scarcely shining, showing rest marks; left
valve with two small pseudocardinals and two laterals; right
valve with one pseudocardinal, a rudimentary one in front, and
a somewhat double lateral; muscle scars rather shallow ; beak

PLEUROBEMA 803

cavities not deep; nacre whitish, purple tinted and iridescent

behind.

Length 58, height 38, diam. 19 mm.

Upper Tennessee River drainage.

Type locality, Tennessee; Holston River, Washington Co.,
Va.

Unio planior Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145;
jieekes Neeser Phila Vl S60) p: 316; pl 1, fig: 120° Obs.,
NIT, 1869, p. 76, pl. @ fig. 129.

Margaren (Unio) planor Lia, Syn., 1870, p. 35.

Pleurobema planior SIMPSON, Syn., 1900, p. 763.

The only shell I have seen, which I am certain is this, is the
type, which is probably young. Compared with specimens of
estabrookianum of equal size it is more elongated, straighter
on the base, less sulcate and has broken rays. It is less solid
and more compressed than P. breve or its variety.

PLEUROBEMA ESTABROOKIANUM (Lea).

Shell rather large, subrhomboid, compressed, solid, some-
what inequilateral ; beaks compressed but considerably elevated,
slightly turned forward over a narrow lunule, their sculpture
a few strong, irregular ridges; posterior ridge more or less
double, curved, ending near the base in a feeble biangulation ;
above them there is a light, radial depression; anterior end
rounded; base line more or less curved; outline of dorsal slope
almost evenly curved in old shells, angular at the middle in
young ones; surface strongly, concentrically sculptured; epi-
dermis straw-colored in young shells, tawny or greenish-brown
in old: ones, showing rest marks; pseudocardinals strong, two
in the left valve, two or three in the right; left valve with two
laterals; right valve with one, which is sometimes double;
muscle scars well impressed; beak cavities shallow; nacre sil-
very white and thinner behind, thicker and duller colored in
front.

Length 78, height 57, diam. 24 mm.

Upper Tennessee River drainage.

Type locality, Clinch River; Second Creek (Knoxville ?),
Tenn.

804 -PLEUROBEMA

Unio estabrookianus LEA, Pr. Am. Phil. Soc., [V, 1845, p. 164;
Tr. Am. Phil. Soc, X;°1853;:p2 77, pl. vy) Ge. 17; Obs iy;
1848, p. 51, pl. v1, fig. 17-

Margaron (Unio) estabrookianus Lea, Syn., 1852, p. 24; 1870,
P- 35:

Unio estabrokianus Pare, Conch. Sam., III, 1890, p. 152.

Pleurobema estabrookiana SIMPSON, Syn., 1900, p. 763.

Unio striatissimus ANTHONY, Am. Jl. Conch., I, 1865, p. 156,
pl. xu, fig. 1—Sowersy, Conch. Icon., XVI, 1868, pl.
LXXXVI, fig. 460.

Strongly concentrically sculptured and not very inequilateral.

The hinge plate is wide and flat; the muscle scars are deeper

than in any of the allied forms.

PLEUROPREMA SUBPLANUM (Conrad).

Shell decidedly rhomboid, compressed or subcompressed,.
somewhat inequilateral, rounded in front and slightly cut away
below; base line almost straight; dorsal slope subtruncate ;
posterior ridge full, rounded but disposed to be double below,
ending in a narrow, feeble biangulation at the base of the shell ;
beaks high, only moderately full, their sculpture a few strong
ridges, which are heavier and turned up decidedly behind;.
surface with irregular incremental striz; epidermis dirty
greenish, sometimes feebly rayed; left valve with two strong,
ragged pseudocardinals and two short, straight laterals; right
valve with one pseudocardinal and one double lateral; beak
cavities not deep, compressed; nacre whitish, thinner and.
slightly iridescent behind.

Length 45, height 30, diam. 16 mm.

North Carolina and Virginia.

Type locality, Branch of James River, Lexington, Rock--
bridge Co., Va.

Unio subplanus Conran, Monog., IX, 1837, p. 73, pl. xi, fig.
1.—Han ey, Biv. Shells Supp., 1856, p. 383, pl. xx1, fig. 16.
—Kuster, Conch: Cab. Unio, 1862, p. 272. pl. xc fe. 5 —
SIMPSON, Syn., 1900, p. 720.

Margaron (Unio) subplanus Lea, Syn., 1852, p. 33; 1870, p-
54-

PILEUROBEMA 805

Unio subplanum Sowersy, Conch. Icon., XVI, 1866, pl. xuvit,
fig. 252.
More rhomboid and compressed than striatulum, lighter col-
ored and less decidedly rhomboid than brimleyi.

PLEUROBEMA BRIMLEYI (S. H. Wright).

Shell decidedly rhomboid, convex or subinflated, somewhat
inequiliteral; anterior end rounded but a trifle cut away be-
low ; base Jine straight; dorsal slope obliquely truncate; dorsal
line curved a little; beaks rather full, somewhat elevated,
their sculpture not seen: posterior ridge full, narrowly round-
ed; above it, separated by a shallow furrow, 1s a second slight
ridge ; epidermis almost cloth-like, rather dull, dark dirty green-
ish; left valve with two ragged pseudocardinals and two
straight laterals; right valve with one pseudocardinal, and a
faint tooth above it, with one lateral disposed to be double:
beak cavities compressed; muscle scars shallow, small; nacre
bluish and bluish-white, much thinner and iridescent behind.

Length 58, height 36, diam. 21 mm.

Type locality, Neuse River. Also Irwin’s Creek, North
Carolina.

Umio brimleyi S. H. Wricut, Naut., X, 1897, p. 138.—Simp-
SON tG.wnes Netoct: Phila. 1900; pp: So; ‘pl. 1v,-fis. 6; Syn.,
1900, p. 720.

I have seen only the type of this species, which appears to be
perfectly distinct. It is a little more elongated than subplanum,
to which it seems most nearly related, is more decidedly rhom-
boid, is darker and less compressed.

Section PLETHOBASUS Simpson, 1900.

Plethobasus Stapson, Syn., 1900, p. 764.—ORTMANN, Ann.

Car. Mus. VILE, 1912; p: 259.

Shell large, irregularly oval, inflated, solid, somewhat sud-
denly swollen at the posterior base; posterior ridge low and
rounded; beaks rather high, near the anterior end, having a
few strong ridges, which are curved upward behind; a row of
low, irregular tubercles extends from near the beaks to the

806 PLEUROBEMA

post-basal part of the valves; epidermis tawny-brown in the
younger shell, becoming darker with age; hinge plate solid,
not flattened; pseudocardinals triangular, rough; cavity of the
beaks not deep; front part of the shell very heavy ; hinder part
much thinner.

Animal having the mantle somewhat toothed posteriorly ;
branchial and anal openings large, the latter smooth or with
very faint papilla; inner gills the larger, rounded below, free
nearly or quite their whole length from the abdominal sac ;
marsupium occupying the entire outer gills.

Type, Unio esopus Green.

Ortmann, (1. c.), raises this group to generic rank.

PLEUROBEMA AHSOPUS (Green).

Shell irregularly oval, inflated, solid, inequilateral; beaks
full and high, turned slightly forward over a lunule; their
sculpture a few irregular ridges: anterior end rounded; front
half of base rounded; at about the middle of the shell a row of
irregular knobs runs from the beaks to the base; behind this
row of knobs the base line is straight or incurved; outline of
the dorsal slope curved; posterior ridge low, rounded, ending
in a blunt point about on the median line ; surface with uneven,
concentric sculpture; epidermis straw-color and shining in
young shells, becoming brown and roughened in old shells;
left valve with two strong, triangular pseudocardinals and two
stout laterals; right valve with one to three pseudocardinals
and a more or less double lateral; muscle scars nearly round,
impressed; beak cavities rather shallow; nacre white, thicker
in front.

Length 120, height 80, diam. 55 mm.

Ohio, Cumberland and Tennessee river systems; west to
Missouri and Minnesota; Alabama River, according to Call.

Type locality, Pittsburgh, Pa.

Unio wsopus GREEN, Cont. Mac. Lyceum, I, No. 2, 1827, p. 46,
fg. 3.—HAaniry, Biv. Shells, 1843, p. 181, pl. xxtv, fig. 7.
—Catt, Jl. Cin. Soc. N. H., XVIII, 1896, p. 157, pl. vr.

Margarita (Unio) wsopus Lea, Syn., 1836, p. 17; 1838, p. 16.

PLEUROBEMA 807

Margaron (Unio) wsopus Lea, Syn., 1852, p. 23; 1870, p. 34.

Pleurobema @sopus SIMPSON, Syn., 1900, p. 764.

Plethobasus «esopus ORTMANN, Ann. Car. Mus., VIII, 1912,
p. 260, fig. 8. |

Unio cyphia Conrap, New F. W. Shells, 1834, p. 68.

Unio cyphius Say, Am. Conch., VI, 1834.—REEvE, Conch.
Icon., XVI, 1864, pl. vit, fig: 28.

Unio cyphias var. esopus Pavrer, Conch. Sam., III, 1890, p.
150.

Unio scyphius Kusrer, Conch. Cab. Unio, 1861, p. 181, pl.

VLE il

eeue:

I am not positive as to the generic position of this and the
following species, but I am inclined to place them in Pleuro-
bema. No other living species of this genus has any develop-
ment of tubercles, but a great number of fossil forms from the
Tertiary of eastern Europe, which seem to be most like Pleuro-
bema, are decidedly pustulous. The heavy, inflated, high beaks
and the comiparatively shallow beak cavities are characters
found in nearly all the species of this genus. In the single
gravid specimen | examined (one cut of a large number from
different localities) the outer gills were not filled very full of
ova, though they were found throughout their extent, while
the most careful search did not disclose any in the inner gills.

In some specimens the radial ridge of nodules is strongly
developed, so that the knobs become large, often compound
humps. In this case there is a sort of wide radial depression
behind the ridge and in front of the low posterior ridge. In
other shells this ridge of nodules is feeble and there is no
appreciable depression behind it. The species differs from
cicatricosum in being more angular at the base of the nodulous
ridge, and in having a harder, smoother epidermis.

PLEUROREMA CICATRICOSUM (Sav).

Shell subtriangular or subquadrate, somewhat inflated, solid,
inequilateral ; beaks very high and full, turned slightly forward
over a well-developed lunule; in the middle of the disk there
is a curved, radial row of low, irregular nodules, reaching

808 PLEUROBEMA

to the base; posterior ridge low, narrowly rounded, ending
in a blunt point at or below the median line; anterior end
rounded or slightly truncated; base line rounded and quite
full at the termination of the row of nodules, from this to the
posterior point it is straight or slightly incurved; outline of
dorsal slope curved; surface generally sculptured with low,
uneven, concentric ridges; epidermis tawny to brown, lighter
colored on the dorsal slope, silky; left valve with two rather
small, triangular pseudocardinals and two laterals; right valve
with one to three pseudocardinals and a double lateral; beak
cavities rather shallow; muscle scars small, impressed; nacre
white, thicker in front.

Length 70, height 66, diam. 38 mm.

Ohio River; Tennessee; Claiborne, Alabama. The last local-
ity I consider doubtful. Lea gives St. Paul, Minnesota, as a
habitat, but I do not think it possibly can be.

Type locality, Wabash River.

Unio varicosus Lea, Tr. Am. Phil. Soc., [V, 1829, p. 90, pl. x1,
fig. 20; Obs., I, 1834, p. 100, pl. x1, fig. 20—HANntey, Biv.
Shells, 1843, p. 181, pl. xxi, fig. 14—CueEnu, Il. Conch.,
1858, pl. x1, figs. 6, 6a, 6b.

Margarita (Unio) varicosus L&A, Syn., 1836, p. 17; 1838, p. 16.

Margaron (Unio) varicosus LEA, Syn., 1852, p. 23; 1870, p. 34.

Unio cicatricosus Say, N. Harm. Diss., II, No. 19, 1829, p-
292.—Kusver, Conch. Cab. Unio, 1861, p. 185, pl. ivi, fig.
2.—ReEVE, Conch. Icon., XVI, 1864, pls. vii, fig. 31; x11,
fig. 50.

Unio cicatricosus var. varicosus ParEL, Conch. Sam., III,
T8go, p. 148.

Pleurobema cicatricosa Stimpson, Syn., 1900, p. 765.

Unio detectus Frierson, Naut., XXV, 1911, p. 52, pl. 11, lower ;
pl. 111, upper figures.

Unio cicatricoides Frierson, Naut., XXV, 1911, p. 53, pl. 11,
upper figure.

Not so inflated nor so large as P. esopus. The base is more
widely rounded at the end of the row of nodules and the shell
is higher in proportion than it is in that species. The texture

PLEUROBEMA 809

of the epidermis is soft and silky while in @sopus it is hard
and shining.

I change Lea’s name because Lamarck previously applied
the name Unio waricosa to what is no doubt, Alasmidonta mar-
ginata. Mr. T. G. Lea, of Cincinnati, took many specimens of
this species, the shells of which he sent to Dr. Lea, and in
several of them he has written in pencil “not charged” or
“ovaries charged,” with the date, but neither of them seems
to have described the animai. I am somewhat at a loss to
know where to place this curious form. The young are much
like those of Ouadrula solida, and do not show the swellings
until the third or tourth year, and occasionally the adult shell
is nearly smooth.

PIEUROBEMA COMPERTUM (Frierson).

“Shell medium in size. Apparently dimorphic, the females
(?) being broader behind than the males and more rounded,
the males (?) being somewhat triangular and pointed behind,
beaks high and well forward (their sculpture not seen). Epi-
dermis dirty vellow, darker before (as in circulus). Basal
outline rounded and, in the females, expanded in the middle;
shell not very much inflated. The posterior ridge is rounded
and becomes more and more inflated with age. ‘The posterior
area is narrow, with several more or less well-defined lines
from beak to margin. Down the centre of the disk runs a row
of pustules, larger in the females, as well as more numerous.
Inside, the nacre is white, quite thick in front, as far back as
the centre, or row of pustules, from thence it becomes remark-
ably thin in comparison, producing a trough-like excavation
from beak to posterior base. Teeth erect and fairly stout ;
two cardinals and two laterals in the left valve and one each in
the right.

Length 2.3, height 2.1, diam. 1.3 inches.” (Frierson)

Habitat: Clinch and Holston rivers.

Type locality not specified.

Unio compertus Frierson, Naut., XXV, ro1t, p. 53, pl. 1,
middle and lower figures.

810 TETRACENE

“This shell is remotely, if at all, related to the other shells
above mentioned (cicatricosus Say and varicosus Lea). There
is apparently a slight relationship to Unio propinquus in its
general facies. but the species is in reality quite distinct.”

Doubtful and indeterminate species.

PLEUROBEMA ABACUS (Haldeman).

“General form of U. subplanus Conrad. Substance of the
shell thick; umbones approximate, depressed, anterior end
without interior cavity; posterior slope regularly arched; mus-
cular and pallial impressions very well marked; epidermis
brown, rough.

Length 3.8, height 2.0, thickness 1.0 inch.

Hab. Holston River, Tennessee.” (Haldeman).

Unio abacus HatpEMAN, Jl. Ac. N. Sci. Phila., VIII, 1842, p.

202.

ee)

Margaron (Unio) abacus Lua, Syn., 1852, p. 24; 1870, p. 38-
Pleurobema abacus SIMPSON, Syn., 1900, p. 749.

I! am wholly unable to say what this is as it never has been
figured and I have never seen the type. Shells that are in the
Lea collection and others that I have seen labeled Unio abacus
Haldeman are much like Plewrobema appressum and cannot
be the genuine abacus of Haldeman, which according to his
measurements is a longer, larger, form.

The following species are described by Rafinesque, but I am
unable to make them out.

Pleurobema mvytiloides RAFINESQUE, Ann. Gen. Sci. Brux., V,

1820, Pp. 313, pl LX XXII, figs. 3-10.

Pleurobema cineata RAFINESQUE, Ann. Gen. Sci. Brux., V,

1820; p. 313:

TETRAGENE AL.

Male and female shells alike, solid; beak sculpture consist-
ing of coarse, subparallel ridges; beak cavities deep; marsup-
ium filling all four gills, smooth, pad-like.

QUADRULA SII

Genus OQUADRULA (Rafinesque, 1820) Agassiz.

~

Quadrula RAFINESQUE, Ann. Gen. Sci. Phys. Brux., 1820, p.

305.—OrTMANN, Ann. Car. Mus., VIII, 1912, p. 250.
Rotundaria Acassiz, Arch. fur Naturg, 1852, p. 48.
Orthonymus AGassiz, Arch. fur Naturg, 1852, p. 48.

Shell triangular, quadrate or rhomboid, solid, inflated, with
rather prominent beaks, which are generally sculptured with
a few coarse, irregular, subparallel ridges that are inflated
where they cross the posterior ridge; posterior ridge ordinarily
well developed; base often incurved in old specimens; disks
sculptured or smooth; epidermis usually dull colored, dark
and rayless, or feebly raved; hinge plate heavy, wide, flattened ;
pseudocardinals solid, direct, ragged; laterals double in the left
and single in the right valve, often with a small secondary
lateral below the large one in the right valve; cavity of the
beaks deep and compressed; dorsal scars under the hinge plate ;
male and female shells alike.

Animal having the inner gills the larger, generally free
from the abdominal sac the greater part or all of their length;
marsupium occupying all four of the gills throughout, the
whole smooth and pad-like.

Type, Quadrula metanevra Rafinesque.

The forms, which I have placed in the genus Ouadriula,
seem to me to be perfectly well characterized by differences
of the animal and the shell, so much so that I have placed them,
together with a few Asiatic species, in a group of higher than
generic value. In almost all cases the shells of Quadrula are
short and solid, they are quite commonly, though not always,
inflated, and with scarcely an exception the beak cavities are
decp. ‘This last character separates them almost invariably
from the species of Pleuwrobema, in which the beak cavities
are uniformly shallow.

With but few exceptions the epidermis is dark, rough and
rayless. The exception occurs in the section Quadrula, in
which the epidermis is sometimes painted and bright. Two
anomalous forms occur in the United States, the Unio cylindri-

812 QUADRULA

cus of Say and Unio trapezoides of Lea. The former is nearly
cylindrical, and looks like an elongated metanevra. ‘This fact
and the deep beak cavities led me to place it in Quadrula
though I know nothing of the character of the marsupia. Sub-
sequently Mr. L. E. Daniels of La Porte, Indiana, who has
rendered great assistance in furnishing anatomical material,
sent me a lot of gravid specimens of both species. In the
metanecvra all four of the gills were filled with young, the
whole being a rich purple and I was delighted to find that the
marsupia of cylindrica were exactly like those of metanevra in
texture, in color and in occupying all four of the gills, like
pads, differing only in being more elongated.

It has been believed by most students that the Unio trape-
zoides of Lea was closely related to his Unio sloatianus, both
being shaped somewhat alike and having obliquely, plicate
sculpture. This view I held until I carefully examined the
shell. Those of trapezoides have much deeper beak cavities
than the shells of sloatianus and for this reason I placed the
former in Quadrula, in the section Crenodonta, near fplicata,
and the latter in Unio. Recently Mr. Lorraine S. Frierson,
who has been making a study of the anatomy of the Naiades
of Louisiana and Texas, has repeatedly found the trapezoides
gravid, and in each case the marsupia are pad-like, occupying
all four leaves of the branchiz.

If I am right in supposing that the earliest and lowest forms
of the Unionide had radial beak sculpture, that the marsupia
of such forms occupied only the inner gills, that the higher
and more modern forms have concentric beak sculpture and
carry the young in the outer gills only, then the Quadrulas
and the few other forms I have placed with them would be a
sort of transition group. It is quite reasonable, if this sup-
position is correct, that occasionally female specimens placed
in the subfamily Hyriane (Endobranchi@) may have more or
less young in the outer as well as the inner gills and that some
gravid females of the Unionine (Exobranchie) may have the
young in all four of the gills, the inner as well as the outer.
Suter is authority for the statement that the gravid females of

QUADRULA 813

Diplodon menziesii of New Zealand occasionally have some
embryos in the outer gills. One or more examples of the
Anodontoides ferwssacianus, which the writer examined, had
more or less young in the inner gills. And in the Quadrulas
all four gills are filled, though the outer are usually thicker and
more pad-like. Now, if these are transition forms, it would
also be reasonable to expect that the beak sculpture would
sometimes be neither radial or strictly concentric. In most of
the Quadrulas the beak sculpture seems to be a sort of com-
promise between the two patterns, consisting of parallel bars
arranged in zigzags or chevrons. In many of the species of
this genus and of allied groups there are a few strictly radial,
delicate ridges either before or behind the main sculpture.

In Volume XV, page 53, of the Nautilus, Dr. H. von Ihering
has applied the name Quadrulinae to the Quadrulas and allied
forms. My reason for not giving them the rank of a subfamily
is that in the character of the shells, their beak sculpture and in
the anatomy they seem much more nearly allied to the Union-
ine than to the Hyriane.

Section CRENODON’TA Schliuter.

Crenodonta SCHLUTER, Virz. meiner Conch., 1836, p. 33.—Orr-

MANN, Ann. Car. Mus., VIII, 1912, p. 245.

Shell more or less alate; beaks prominent; the surface of
the valves usually sculptured with oblique folds; posterior
slope generally. having smaller radial plications, which curve
upward behind; epidermis brownish or blackish ; anterior mus-
cle scars large, distinct, very shallow, the anterior edge
smooth, the rest apparently filled with roughened shelly mat-
ter ; posterior scars large, shallow, indistinct ; escutcheon large
and dark.

Animal with the gills generally large, rounded below ; inner
the larger, usually free nearly or quite the entire length of the
abdominal sac, the two pairs united to the mantle nearly, but
not quite, to the posterior end, having a small portion free;
marsupium occupying all the four branchize, forming very
heavy, thick pads; labial palpi usually large.

Type, Unio plicatus Say.

814 QUADRULA

Schluter applied the name Crenodonta to a group of Union-
ide, the first species of which was the Unio plicatus of Say,
but he gave no description of his group and did not designate
a type. In 1853 Morch (Yoldi catalogue, p. 45) used this
name without a description or a type, and it has been applied
to the plicate uniones by von Martens (Biologia Centrali-
Americana, Mollusca, 1900, p. 479).

ORTMANN, (1. ¢.), raises this group to generic rank.

Dr. Lea found in Quadrula heros the inner gills generally
nearly or entirely free, but in certain specimens they were
wholly united. My own experience in examining the animals
of this species exactly coincides with his, thus showing that
the character of the union of the inner gills with the abdom-
inal sac, or their separation from it, is not a generic character,.
as Agassiz beheved, nor is it even of specific value.

Group of Ouadrula plicata.

Shell rounded to subrhomboid; plications usually strong,
oblique, though in occasional specimens the surface may be
perfectly plain or slightly concentrically sculptured.

QUADRULA PLICATA (Say).

Shell subquadrate or subrhomboid, inflated, solid, inequilat-
eral; beaks full and high, turned forward over a well-marked.
lunule, their sculpture consisting of a few coarse, irregular,
somewhat corrugated ridges; anterior end generally narrowed
a little, rounded and often cut away somewhat below; base
line rounded or nearly straight: dorsal slope often carried up
into a low wing, obliquely truncated behind; posterior ridge
rounded ; above it there is often a wide, shallow, radial depres-
sion; surface with uneven, concentric sculpture and having
usually several very strong, irregular ridges below the pos-
terior ridge running nearly parallel with it; posterior slope
with or without radial ridges; epidermis yellow-green, brown-
ish or blackish, generally coarse and rough; left valve with
two strong, radial pseudocardinals, which are often split into
a number of radial denticles, with two strong laterals; right

QUADRULA 815

valve with three pseudocardinals, the middle one large and

frequently much split, with one lateral, which is sometimes

partly double; beak cavities deep, compressed; muscle scars
shallow, the anterior very rough; nacre white, much thinner
and iridescent behind; pallial line strongly crenate.

Length 1109, height 83, diam. 54 mm.

length 120, height 90, diam. 46 mm.

Length 90, height 62, diam. 52 mm.

Upper Mississippi drainage area south to the Tennessee and
Arkansas rivers; Red River of the North; Saskatchewan Riv-
er; Lake Winnipeg; western Michigan.

Type locality, Lake Erie.

Unio plicata Say, Nich. Encyc., II, 1817.

Unio (Theliderma) plicata Swatnson, Tr. on Mal., 1840, p.
271, fig. 54e.

Mya plicata Eaton, Zool. Text-Book, 1826, p. 219.

Ouadrula plicata BAKER, Moll. Chicago, Pt. 1, 1898, pl. xxv,
fig. I.—SIMPSON, Syn., 1900, p. 767.

Unio plicatus HAntEy, Biv. Shells, 1843, p. 175, pl. xx1, fig.
21.—KustER, Conch. Cab. Unio, 1856, p. 137, pl. XL, fig. 3.
—Rerrve, Conch. Icon., XVI, 1864, pl. 11, fig. 5.

Margarita (Unio) plicatus Lea, Syn., 1836, p. 12; 1838, p. 14.

Margaroen (Unio) plicatus Lea, Syn., 1852, p. 20; 1870, p. 30.

Plectomerus plicatus Conran, Pr. Ac. N. Sci. Phila., VI, 1853,
p. 261.

Unio peruziana L,AMARCK, An. sans Vert., VI, 1819, p. 71.—
Drsuayrs, Encyc. Meth., 1827, pl. 248, fig. 7; pl. 249, fig. 1.

Unio crassus BARNES, Am. Jl. Sci., VI, 1823, p. 118.

Unio rariplicata DesHayes, Enc. Mth., II, 1830, p. 578.

Unio giganteus Lea, Obs., II, 1838, p. 35.

Unio heros Kuster, Conch. Cab. Unio, 1856, p. 136, pl. Xt,
Bes. Te 2.

An exceedingly variable species in general form, degree of
inflation. development of beaks, etc. As in most of the species
of this group there are occasional specimens that are wholly
destitute of plications. Normally it is perfectly distinct from
its near ally Ouadrula undulata, being more inflated, solider

816 QUADRULA

in proportion, shorter and having much fuller, higher beaks

but there are intermediates, which can hardly be placed. The

beaks of plicata are generally a little nearer the anterior end
than those of wndulata.

Say says: “It was found by Mr. Lesueur in Lake Erie, and
was communicated by him under the above name.” As there
is no evidence that Lesueur described the species, and as Say
was the one to first properly characterize it, I believe that he
must be credited with it.

Var. hippopea (Lea).

Smaller and more delicate than the type; epidermis green-
ish, greenish-brown or reddish-brown.

Length 60, height 42, diam. 27 mm.

Type locality, Lake Erie. Also, Eastern Michigan.

Unio hippopeus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 163;
Tr: Am. Phils Soe.;--X,. 1848.-p: (67, pl. a, ie. Obs ve
1848, p. 41, pl. 1. fig. 1—Kuster, Conch. Cab., 1861, p. 251,
pl. LXxx1v, fig. 3—Reerve, Conch. Icon., XVI, 1864, pl. x1,
fig. 40.

Margaron (Unio) hippopeus Lea, Syn., 1852, p. 21; 1870, p.
2.

Quadrula plicata var. hippop@a SIMPSON, Syn., 1900, p. 767.

Crenodonta plicata ORtTMANN, Ann. Car. Mus., VIII, 1912, p.
24h.

Very variable in form and size. Some adult shells are very
much smaller than the measurements given above. A form of
plicata left in the St. Lawrence drainage at the close of the
Glacial Epoch, no doubt, and developed by its environment.

Ortmann, (1. c.), says, “this species has been misunderstood
hitherto. ‘The type locality of plicata is Lake Erie, and thus
the only known Crenodonta from Lake Erie should bear this
name, but this is the form called hippopea by Lea. The pli-
cata of authors should be Cr. peruviana (Lamarck).”

He also says that “this is undoubtedly only a local race of
undulata.” If this is correct, plicata Say would take precedence
over undulata Bar. as the specific name for that species.

QUADRUTA 817

QUADRULA PERPLICATA (Conrad).

Shell subrhomboid, inflated, solid, inequilateral; beaks full
and high, turned forward over a well-marked lunule, their
sculpture a few strong, irregular bars; anterior end rounded,
a little narrower than the posterior end, often cut away a little
below ; base line: curved; post-dorsal slope usually developed
into a slight wing, the hinder part obliquely truncate; surtace
with light, irregular, concentric ridges, and with very strong,
oblique ridges on the hinder half of the disk that run well
on to or cross the posterior ridge; epidermis dark brown or
nearly black, often subshining; pseudocardinals strong, radial,
much split, two in the left valve and three in the right; two
laterals in the left valve and one in the right; muscle scars
shallow, the anterior ones rough; beak cavities deep, com-
pressed; nacre white. generally purple-tinted and iridescent
behind.

Iength 145, height 110, diam. 60 mm.

Length 87, height 67, diam. 55 mm.

Alahama River drainage and streams flowing into the Gulf
of Mexico west to central Texas, north to southern Kansas.

Type locality, Jackson, La.

Umo perplicatus Conrap, Pr. Ac. N. Sci. Phila., I, 1841, p.
fOr ae, Ne ocls nila. 1850, -p. 276, pl. xxxvin, fig.
—Rerve, Conch. Icon., XVI, 1864, pl. 1x, fig. 35.

Margaren (Unio) perphicatus Lea, Syn., 1852, p. 20; 1870, p.
20. .

Plectomerus perplicatus Conrap, Pr. Ac. N. Sci. Phila., VI,
£953, p: 201.

Ouadrula perplicata Stmeson, Syn., 1900, p. 767.

Crenodonta perplicata ORTMANN, Ann. Car. Mus., VIII, ro12,
Pp. 247.

Unio atrocostatus Lea, Tr. Am. Phil. Soc., X, 1848, p. 70, pl.
im ne.-5 Obs. 1V, 1848. p. 44) pl. 1, fig. 5.

Margaron (Unio) atrocostatus Lea, Syn., 1852, p. 20; 1870,
p. 20.

Unio pearlensis Conrad, Tr. Am. Phil. Soc., VII, 1855, p. 256.
—Reeve, Conch. Icon., XVI, 1864, pl. xt, fig. 42.

Unio perlensis Pater, Conch. Sam., IIT. 1890, p. 163.

bo

818 QUADRULA

Unio bragesensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144;
JL. Ac.“ N."Set.-Phila:. V1, 1660, p.- 3009 ply sci, sno oar
Obs., XII, 1860, p. 69, pl. xLvui1, fig. 122.

Margaron (Unio) brazosensis Lea, Syn., 1870, p. 31.

Unio lincecumti Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144;
Jl. Ac. -N. Sei Phila, VI 1860; p32) sple <i ie ee
Obs., XII, 1860, p. 72, pl. x11x, fig. 125.

Margaron (Unio) lincecumu Lea, Syn., 1870, p. 31.

Unio lincecuru Pare.., Conch. Sam., II, 1890, p. 157.

Umo pauciplicatus Lea, Pr. Ac. N. Sci. Phila., I], 1872, p.
1565 0L Ac Ne Sei Phila, Vill 8745p. 20. ple renee 2
©bs., SEM 8 74. 9:33, plaixe se. 2,

This has.about an equal degree of inflation as Q. plicata, but
as a rule its beaks are not so high, its outline is less rhom-
boid, the ridges are stronger and cover more of the shell.
They sometimes extend behind the posterior ridge and curve
up to the hinder end of the dorsal slope. Generally it is a
smoother, more shining shell than plicata and the nacre is
more often tinted with purple. The Unio atrocostatus of Lea
is a little shorter than the ordinary manifestation of the spe-
cies, seeming to stand between it and elliottiu, but it hardly
seems to me to be worth a.varietal name. U. brazosensts,
pauciplicatus and lincecumti are merely forms more or less
destitute of plications.

Var. quintardu (Cragin).

Shell with light brown, glossy epidermis; surface with a
series of V-shaped ridges on the disk.

Kansas.

Type locality, Salt Creek, Sac and Fox Reservation, Okla-
homa.
Unio quintardu Cracrn, Bull. Wash. College, I, 1887, p. 6—

Prispry) Pry Ac. IN. Set. Phila; 1892, p13. plow, tiess ise
Quadrula perplicata var. quintardit SIMPSON, Syn., 1900, Pp.

768.

I do not think this form worthy of a specific name. It often
happens that shells of other related species show decided traces
of V-shaped sculpture.

QUADRULA 819

QuapRULA ELLIOTTIL (Lea).

Shell subquadrate or subtrapezoidal, inflated, solid, inequt-
lateral; beaks only slightly elevated or inflated, their sculpture
a few strong, somewhat corrugated ridges that curve up
strongly behind; anterior end somewhat narrowed and round-
ed; base line lightly curved; dorsal line straight or nearly so;
posterior end almost squarely truncate ; posterior ridge scarcely
developed; surface sculptured with uneven concentric ridges
and with 6 to 8 very strong, oblique folds; these fade out be-
fore reaching the anterior end and trend in the direction of
the posterior base; dorsal slope strongly plicate; epidermis
often bright green in young shells, brownish to blackish in old
shells ; pseudocardinals low and rather small, ragged and some-
what split up, two in the left valve and two to three in the
right ; left valve with two short laterals; right valve with one;
beak cavities deep, compressed, muscle scars shallow, the an-
terior partly filled with roughened nacre; pallial line deep, re-
mote from the border; nacre white, iridescent behind.

Length 130, height 112, diam. 67 mm.

Southern Georgia; west to Texas.

Type locality, Othcalooga Creek, Gordon Co., Ga.

Unio elliottti Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 262;
je Ae N= Sct. sPhbila., 1V, 1858) p: 543. pl. vu, fig.. 37; Obs.,
VI, 1858, p. 54, pl. vi, fig. 37—Reeve, Conch. Icon., XVI,
1864, pl. v, fig. 20.

Margaron (Unio) elliotiti Lea, Syn., 1870, p. 29.

Ouadrula elliottii Simpson, Syn., 1900, p. 768.

T am strongly inclined to believe that this is only a variety
of perplicata. It is more decidedly quadrate than that species,
the anterior end is narrowed and the pseudocardinals are
smaller and less elevated. ‘The Unio atrocostatus of Lea
seems to be to a certain extent a connecting form.

QUADRULA UNDULATA (Barnes).

Shell somewhat elongated, irregularly rhomboid, subcom-
pressed to subinflated, solid, inequilateral ; beaks only moder-
ately elevated and inflated, their sculpture a°few strong ridges,
which are swollen where they cross the posterior ridge; pos-

820 QUADRULA

terior ridge low and rounded; anterior end rounded ; basal and

dorsal lines curved; posterior end obliquely truncated above,

pointed or rounded below; surface concentrically sculptured
and having uneven, oblique folds on the hinder half of the
disk, which run nearly parallel with the posterior ridge and
are sometimes broken into corrugations or pustules; dorsal
slope usually having radial plications; epidermis greenish or
yellow-green and sometimes rayed in young shells, becoming
brown or blackish with age; pseudocardinals strong and rag-
ged, two in the left valve and two or three in the right; left
valve with two laterals; right valve with one; beak cavities
deep, compressed; muscle scars shallow, the anterior partly
filled with rough nacre; pallial line deep, remote; nacre whit-
ish, iridescent and thinner behind.

Length 165, height 108, diam. 60 mm.

Length 140, height 97, diam. 60 mm.

Length 136, height 93, diam. 42 mm.

Mississippi basin generally; St. Lawrence drainage; Red

River of the North; Lake Winnipeg; Alabama River system.
Type locality, Ohio River.

Unio undulatus Barnes, Am. Jl. Sci., VI, 1823, p. 120, pl. 11—
Hantry, Biv. Shells, 1843, p: 175, pl. xx, fig. 26—CHENU,
ib; Conch, rst -ser:, TM; 1845, p: 24,°pl. v, figs! 1, 10; Man-
ual, 1859. Il, p. 143, fig. 704.—Sowerrsy, Conch. Icon., XVI,
1868, pl. LXXVvI, fig. 390.

Margarita (Unio) undulatus Lia, Syn., 1836, p. 12; 1838, p.
T4.

Margaron (Unio) undulatus Lea, Syn., 1852, p. 20; 1870, p.
20.

Mya undulata Eaton, Zool. Text-Book, 1826, p. 219.

Unio undulata VALENCIENNES, Rec. Obs. Zool. Anat., II, 1833,
p. 229, pl. Liv, figs. 3, 3a, 3b.—Desuayves, Tr. Elem. Conch.,
1920; Pp. tOsple xxx, f1es.8, 10:

Ouadrula undulata BAKEr, Moll. Chicago, Pt. I, 1898, p. 82,.
pl. xxu1, figs. 1, 2; xm, fig. 1—Srmpson, Syn., 1900, p. 769.

Crenodonta undulata Orrmann, Ann. Car. Mus., VIII, 1912,
p. 246.

QUADRULA 821

Onio costatus CONRAD, Monog., II, 1836, p. 17, pl. vir.—Kus-
TER, Conch. Cab., 1852, p. 54, pl. x1, fig. 4.—Rerrve, Conch.
Icon., XVI,. 1864, pl. tv, fig. 16.

Plectomerus costatus Conrap, Pr. Acad. N. Sci. Phila., VI
1853, p. 260.

Unio plicatus Kuster, Conch. Cab., 1856, p. 137, pl. x1, fig. 3.
—CueEnv, Manual, 1859, IJ, p. 143, fig. 706.

Unio atrocostatus Sowrersy. Conch. Icon., XVI, 1868, pl.
LXXvVII, fig. 404.

Var. latecostata (lea).

This is possibly worthy of a varietal designation. It is gen-
erally not quite so solid as the tvpical form and the oblique
folds are finer and more numerous.

Length 135, height 85, diam. 50 mm.

Type locality, Tuscaloosa, Alabama. Also, Illinois; Mis-
souri: south to Texas.

Unioriatecosiatus ma, Pr. Am. Phil. Soc., 1V, 1845;. p. 1633
ime. Philo Soc. ©, 1648,, p. 68, pl. 1, fig. 2; Obs., TV,
1848, p. 42. pl. 1, fig. 2—Kusrer, Conch. Cab., 1861, p. 251,
Pile Lx ety, fis. 4.

Margaron (Unio) laticostasus Lea, Syn., 1852, p. 21.

Margaron (Unio) laticostatus LEA, Syn., 1870, p. 31.

Umio laticostatus H. and A. ApAMs, Gen. Rec. Moll., II, 1857,
P. 497.

Ouadrula undulata var. latecostata Stimpson, Syn., 1900, p.
760.

More delicate in every way than the type, but connecting
with it.

Var. pilsbryi (Marsh).

Shell subrhomboid, slightly inflated and thickened before,
compressed and thin behind; epidermis dark reddish-brown:
plications small. seminodulous.

Kansas.

Type locality, Little Red River, Arkansas.

822 _ QUADRULA

Unio pilsbryt Marsu, Nautilus, V, 1891, p. 1.—Prispry, Pr.
Ac. N. Sci. Phila. 1892, p. 131, pl. vit, figs. 7, 8; Nautilus,
VIL 18093" plaseehes ge:

Quadrula undulata var. pilsbryt SIMPSON, Syn., 1900, p. 760.

I do not think this 1s more than a variety of wndulata. It is
more wedge-shaped when viewed from above, has a browner
epidermis than the ordinary manifestation of that species, and
the plications are somewhat broken into nodules, a character
often found in wndulata.

On the one hand this species closely approaches Q. plicata
and on the other it almost connects with forms of Q. heros.
Ordinarily it is much more compressed, is shorter and has
lower and less inflated beaks than the former, but there is a
great deal of intermediate material. Frequently the strong,
oblique folds become broken up by cross folds until the sculp-
ture so closely resembles that of heros that the two forms can
scarcely be separated. The Unio pilsbryi of Marsh shows
something of this style of sculpture.

A peculiar shell belonging to Mr. J. H. Ferriss, of Joliet,
Illinois, from Iake Winnipeg, has been examined by the writ-
er. It has unusually strong growth lines and is quite full in
the ventral region, and has only the very faintest vestiges of
plications below the lower part of the posterior ridge. I re-
gard it as a smooth form of Q. undulata, and if any consid-
erable number of such specimens were found it might be
worthy of a varietal name.

QuapruLA picITATA. (Morelet).

Shell large, very solid, subcompressed, irregularly elliptical
or subrhomboid ; beaks moderately developed ; dorsal line near-
ly straight; anterior end rounded and cut away somewhat be-
low; base line nearly straight; posterior end rounded, some-
what pointed about on the median line, angular above; surface
strongly, concentrically striate, and nearly covered with strong
folds, which radiate from behind the beaks to a point some-
what lower on the disk and extend to the border of the shell ;
anterior end having low, rather regularly arranged pustules ;

QUADRULA 823

epidermis dark brown or blackish; pseudocardinals somewhat
split up radially ; laterals lamellar; muscle scars large, shal-
low, the anterior partly filled with roughened nacre; nacre
white.

Length 125, height 92, diam. 46 mm.

Rio Usumacinta, Guatemala.
Unio digitatus Moree, Test. Noviss., Pt. 2, 1851, p. 24.—

FiscHrr and Crossr, Miss. Sci., II, 1894, p. 563, pl. Lx, fig. 1.
Quadrula digitata SIMPSON, Syn., 1900, p. 770.

The prominent and distinguishing characters are the radiat-
ing ribs, about 15 in number that start from behind the beak
and along to a point lower down the disk and extend back-
ward and outward to the extreme edge of the shell from the
middle of the ligament to the base, and the small, regularly
arranged pustules on the anterior end.

QUADRULA TRIUMPHANS (B. H. Wright).

Shell short, irregularly obovate, scarcely subinflated, inequi-
lateral, solid: beaks low and compressed; anterior end nar-
rowed and rounded; base line lightly curved; dorsal outline
nearly straight, elevated into a wing; posterior end somewhat
obliquely truncated above, widely rounded below ; surface cov-
ered with concentric growth marks and narrowly spaced rest
marks, having a series of folds, which radiate backward and
outward from below the region of the beaks, these folds are
strongest below and aré somewhat corrugated, broken and
divaricate ; along the anterior end and anterior base there are
numerous uneven tubercles; epidermis blackish; pseudocardi-
nals rather small, radial and radially striate; laterals granu-
late ; beak cavities deep and compressed; anterior scars small,
slightly roughened: nacre whitish or flesh-color, thinner, pur-
plish and iridescent behind.

Length 105, height 94, diam. 40 mm.

Type locality, Coosa River, St. Clair County, Alabama.

Unio triumphans B. H. Wricut, Naut., XI, 1898, p. ror.
Ouadrula triumphans Simpson, Pr. Ac. N. Sci. Phila., 1goo,
p. 83, pl. 11, fig. 3; Syn., 1900, p. 770.

824 QUADRULA

In some characters this species is close to O. boykiniana.
‘The general sculpture is much as it is in that species, but in the
type, the only absolutely authentic specimen I have seen, there
is no indication of chevron shaped patterns. I have seen ma-
terial, which hints strongly at a connection of the two species
and would not be surprised if it would eventually be found
necessary to unite them, different as they are typically.

(QUADRUI,A BOYKINIANA (Lea).

Shell trapezoid or subrhomboid, subinflated to inflated, solid,
inequilateral ; beaks full and elevated, their sculpture consist-
ing of coarse, sometimes doubly looped or zigzagged, nodu-
lous ridges; anterior end narrowed and rounded, often full
and subangular above and slightly cut away below; base line
straight or nearly so; post-dorsal part produced into a rather
high wing; posterior end almost squarely or obliquely trun-
cate, rounded or pointed below the median line; posterior ridge
moderate to full, rounded; surface with strong, irregular con-
centric sculpture and covered with oblique, corrugated or sub-
nodulous plications. These folds are generally strongest along
the posterior portion, where they are often divaricate and they
frequently are formed into irregular, chevron-shaped patterns
on the anterior half of the shell; epidermis dark brown or
blackish; pseudocardinals radially striate, often uneven and
broken up; laterals granular; beak cavities deep, compressed :
posterior scars indistinct; anterior scars nearly filled with
rough nacre; nacre white, often dull purplish in the cavities,
much thinner and iridescent behind.

Length 162, height too, diam. 63 mm.

Length 112, height 86, diam. 43 mm.

Chattahoochee River system: Claiborne, Alabama; Pine
Barren Creek, Escambia County, Florida.

Type locality, Chattahoochee River, Columbus, Ga.

Unio boykinianus Lea, Pr. Am. Phil. Soc., I, 1840, p. 288;
Tr. Am., Phil, Soc:, VEL, 1842) ps 208 spl saiias 222s
Obs., III, 1842, p. 46, pl. x11, fig. 22—CueEnu, Ill. Conch.,
188, pl. xxvit, figs. 2, 2a, 2b—Kuster, Conch. Cab., 1861,
p. 181, pl. tvi, fig. 1—Sowexrey, Conch. Icon., XVI. 1868,
pli fiesta

QUADRULA 825

Margaron (Unio) boykimanus Lea, Syn., 1852, p. 19; 1870,

p. 28.

Plectomerus boykinianus Conrap, Pr. Ac. N. Sci. Phila., VI,

1853, p. 260.

Quadrula boykiniana SIMPSON, Syn., 1900, p. 770.
Unto baykinianus Pairer, Conch. Sam., III, 1890, p. 145.

Differs from Q. triwmphans in being longer in proportion
to its height, in being less rounded and in having chevron-
shaped sculpture. But it is quite probable that the two will be
found to run together, when a sufficient amount of material
is examined.

QUADRULA HEROS (Say).

Shell long rhomboid or long quardate, subintlated to inflated,
solid, inequilateral ; posterior ridge usually full, rounded ; beaks
rather full and high, their sculpture strong, doubly looped or
zigzag ridges; dorsal line straight or lightly curved; anterior
end rounded, generally angled above; base line straight or a
little curved; posterior end almost squarely or somewhat
obliquely truncate and angled above where it joins the low
dorsal wing, rounded below; surface with uneven,. concentric
sculpture, all, except the anterior basal part, more or less
covered with oblique folds and nodules. The earlier growth
is usually densely covered with subradial or chevron-shaped,
nodulous plications; frequently the sculpture in front is de-
cidedly nodulous: epidermis brownish or blackish; pseudo-
cardinals elevated, radial, radially striate; laterals straight or
slightly curved; muscle scars large, the anterior ones with
rough nacreous matter; beak cavities deep, compressed ; nacre
whitish, often blotched with lurid color, much thinner and irt-
descent behind; pallial line remote.

Length 210, height 133, diam. 70 mm.

Length 133, height 91, diam. 60 mm.

Length 112, height 82, diam. 55 mm.

Mississippi River system generally ; Red River of the North;
Tombigbee River, Alabama; southwest to New Leon, Mexico.

Type locality, Fox River, tributary of the Wabash.

826 QUADRULA

Unio heros Say, New Harm. Diss., II, No. 19, 1829, p. 291.—
Conrap, Monog., XII, 1840, p. 107, pl. L1x.—HANLEy, Biv.
shells, 18435 p.175: pl. xxi figs 28:

Quadrula heros SIMPSON, Syn., 1900, p. 770.

Crenodonta heros ORtMannN, Ann. Car. Mus., VIII, 1912, p.
248.

Unio heros var. multiplicatus Pavren, Conch. Sam., II], 1890,
p. 155. |

Unio undulatus Say, Am. Conch., I, 1831, pl. xvi (April).

Unio multiplicatus Lua, Tr. Am. Phil. Soc., TV, 1831, p. 70,
pl. iv, fig. 2 (latter part of the year) ; Obs. I, 1834, p. 80, pl.
Iv, fig. 2—Potirz and Micuaup, Gall. Moll., 1844, p. 155,
pl. Lx, fig. 1—CnHeENu, Ill. Conch., 1858, pl. rx, figs. 2, 2a,
2b;.Manual, 1859; 11; pri435 fic. 7032.

Margarita (Unio) multiplicatus Lea, Syn., 1836, p. 12; 1838,
po ae

Margaron (Unico) multiplicatus Lea, Syn., 1852, p. 20; 1870,
p: 20.

Unio. eighisa, Lea, Pr. Ace N.-oet-Phila, lV 1860, +p 4065
Ji Ae: N. Sct: Phila SsIV3 1860)p. 367. ple xiv.ties eer
Obs., VEIT, 1860;: p40; plo ixiv, fige 192:

Margaron (Umno) eightsu La, Syn., 1870, p. 20.

Unio eighti Pztet, Conch. Sam., III, 1890, p. 151.

Unio atrocostatus Reeve, Conch. Icon., XVI, 1864, pl. tv, fig.
13. (Changed in Errata to Unio heros.)
his is one of the largest known North American Uniones.

Specimens have been reported exceeding the largest dimen-

sions given above, which are those of a specimen taken from

the Little Miami River, near Cincinnati, Ohio, and is in the

I.ea collection. J,ea’s shell is 8 inches long and weighs 2 lbs.

9:5 oz, Dro WAS: Strode‘in-the: Nautilus, Vol “Exp. 10 re-

ports a specimen of this species from the Spoon River, Illinois,

8.5 inches in length, Symphynota complanata the same length

~and “Lampsilis alata 9 inches long. I can see no reason for

separating Unio eightsii from heros even varietally. The spe-
cies apparently extends through Mississippi, Louisiana and

Texas well into Mexico.

QUADRULA 827

There has been some dispute as to what name should be
applied to this species. In 1829 Say fully described in the New
Harmony Disseminator a species, which he called Unio heros,
but did not figure. Later in the American Conchology he
placed it in the synonymy of Unio undulatus Barnes, though
the figure, which he gives as undulatus in that work and to
which his description refers, is plainly not Barnes’s species,
but the heros described in the Disseminator. In 1831 Dr. Lea
described Say’s species as Unio multiplicatus. Notwithstand-
ing the fact that Say placed his own species in the synonymy,
it is perfectly distinct and was properly characterized in his:
description, and his name will have to take the place of the bet-
ter known one of Dr. Lea.

QUADRULA NICKLINIANA (Lea).

Shell short trapezoid, compressed, solid, inequilateral, beaks
rather elevated, subcompressed, or slightly inflated, their sculp-
ture strong, somewhat zigzagged, ridges; anterior end nar-
rowed and rounded; base line somewhat curved; dorsal out-
line produced into a wing, which is somewhat obliquely trun-
cated behind; posterior ridge nearly wanting, feebly and very
widely double, the lower ridge often being developed into a
wide lump or swelling about the middle; the whole ending be-
low ina very wide, faint biangulation at and below the median
line; surface rudely, concentrically sculptured. The posterior
end has a few, more or less strongly developed, radial folds
and besides these there is a set of fine, radial wrinkles reach-
ing to the front of the posterior ridge. In front of this the
umbonal region is sculptured with broken corrugations, which
change into irregular, radial wrinkles and pustules below; epi-
dermis greenish-brown ; pseudocardinals rough, radial ; laterals
short, remote: beak cavities very deep and compressed ; mus-
cle scars large, shallow, the anterior filled with roughened
nacre; pallial line remote; nacre white, very thick on anterior
base, suddenly becoming thin behind.

Length 145, height over all 125, diam. 47 mm.

Mexico ; Guatemala.

828 QUADRULA

Unio nicklinianus Lua, Tr. Am. Phil. Soc., V, 1834, p. 28, pl.
1, fig. 1; Obs., 1, 1834, p. 140, pl. 1, ig. 1—HaNLEy, Biv.
Shells, 1543, p. 175, pl. XXI, hg. 52.—SoweERBy, Conch. Icon.,
AV 1 1666, pl rau, e270:

Margarita (Unio) mckunianus Lea, Syn., 1836, p. 12; 1838,
De EA:

Margaron (Umo) mcklinianus Lua, Syn., 1852, p. 19; 1870,
Dp. 28.

Plectomerus nicklinianus Conran, Pr. Ac. N. Sci. Phila., VI,
1853, p. 261.

Quadrula nickliniana SIMPSON, Syn., 1900, p. 771.

Unio nicklianus Kustrr, Conch. Cab., 1861, p. 218, pl. Lxxrt,
fig's:3:

Shorter than Q. stolli, having a more elaborate pattern of
sculpture and usually a sort of hump on the middle of the
lower posterior ridge. I am able to separate Lea’s shells,
which he calls Unio nicklinianus, into two lots, one agreeing
with his type, the other longer and answering very well to the
description and figure of Unio stolli von Martens.

QUADRULA STOLLI (von Martens).

Shell subtrapezoid, compressed, solid, quite inequilateral ;
beaks compressed and rather low; dorsal line nearly straight,
produced into a gradually expanding wing behind; posterior
slope with a long oblique truncation, angled above, rounded
below ; base line nearly straight; anterior end somewhat nar-
nowed and rounded, angled a little below the beaks; surface
covered with low, radiating, somewhat corrugated or broken
folds, whose radius is below the beaks and which spread out
behind in light curves; there is also moderate concentric sculp-
ture; pseudocardinals strong, radial, rough, two in the left
valve and three in the right; laterals heavy, remote, two in the
left valve and one in the right ; beak cavities deep, compressed ;
muscle scars large, the anterior nearly filled with roughened
matter; nacre white, much thicker in front; pallial line re-

mote.
Length 160, height over all 120, diam. 40 mm.
Rio de las Salinas, Guatemala; Moctezuma River, Central

America?

QUADRULA 829

Unio stolli von Martens, Biol. Cent. Amer., Moll., 1900, p.

492; (pl: SxXix,- fie’ 2.

Quadrula stolli Simpson, Syn., 1900, p. 771.

I am inclined to believe that this is a valid species. It seems
to be uniformly more elongated than Q. nickliniana, the nacre
is not so suddenly or greatly thickened in front and it lacks
a swelling just back of the middle of the shell generally seen
in that species. The sculpture near the beaks is considerably
corrugated and broken. von Martens believes that Kuster’s
Unio nicklianus (Conch. Cab. Unio, p. 217, pl. Lxxitt, fig. 3)
is not the nicklinianus of Tea, but his species. I cannot agree
with him in this.

QUADRULA NEISLERII (Lea).

Shell subquadrate, inflated, solid, inequilateral ; beaks mod-
erately full and high; posterior ridge high, narrowly rounded,
sometimes slightly double, ending at the base in a feeble bian-
gulation or a blunt point; anterior end narrower and rounded ;
base line nearly or quite straight; post-dorsal slope scarcely
winged above, almost squarely truncated behind; surface with
the usual concentric sculpture of the group and having, often,
throughout all the shell, except the extreme anterior end, a
series of nearly horizontal, moderate folds, these sometimes
descend a very little in front and behind and on the dorsal slope
they curve slightly upward; in the umbonal region the sculp-
ture is corrugated somewhat as in Q. heros; epidermis brown-
ish to blackish; pseudocardinals radially striate, often radially
split up; laterals short; beak cavities moderately deep, com-
pressed; anterior scars partly filled with rough nacre; nacre
whitish or purplish, iridescent and slightly thicker behind.

Length 80, height 65, diam. 43 mm.

Type locality, Flint River, amer Co., and Macon, Georgia.
Unio neislerii Lea, Pr. Ac. N. Sci. Phila., I, 1858, p. 165; Jl.

Ac WN. Sci. Phila, DY; 1859: \p. 212, pl. xxvi, fig. 93; Obs.,

VII, 1859, p. 30, pl. xxvt,. fig. 93.

Margaron (Unio) neislerti Lea, Syn., 1870, p. 29.
Quadrula neislerii Simpson, Syn., 1900, p. 771.

830 QUADRULA

A rather small member of the plicata group, always much
inflated, decidedly quadrate and having delicate, almost hori-
zontal folds. ‘The posterior ridge is always full. I have seen
a specimen without locality, which I refer to this, in which
the folds are almost wanting. <A shell of trapezoides before
me is shaped almost exactly like neislerii, but it has only a few
short folds in front of the posterior ridge and a deep purple
nacre.

Group of Ouadrula trapezoides.

Shell rhomboid, inflated, with a high posterior ridge; beak
sculpture coarse, irregular corrugations swollen to nodules
on the posterior ridge; surface sculptured on posterior half
with oblique ridges, which are sometimes corrugated, and with
strong corrugations on post-slope; beak cavities only moder-
ately deep; nacre purple.

Animal with the gills slightly rounded below, inner the
larger throughout, free from the abdominal sac; palpi enor-
mous, long ; branchial opening very large, finely papillose ; anal
opening with fine papillz or crenulations.

QUADRULA TRAPEZOIDES (Lea).

‘Shell long rhomboid, subinflated to inflated, solid, inequilat-
eral; beaks only moderately full and high, their sculpture con-
sisting of a few decidedly nodulous corrugations; posterior
ridge strong and high, often pinched up into a sharp angle,
ending at the base of the shell in a point; anterior end a little
narrowed and rounded: base line straight; post-dorsal area
somewhat winged; posterior end obliquely truncated with a
slightly curved outline; surface with a few oblique folds in
front of the posterior ridge and on the posterior end there are
curved folds; umbonal region with lengthened nodules ar-
ranged in zigzagged patterns; epidermis brownish or black-
ish; pseudocardinals ragged, radially split; laterals long; mus-
cle scars large, the anterior ones filled with roughened nacre ;
beak cavities moderately deep; pallial line remote; nacre pur-
ple-red.

Length 160, height too, diam. 65 mm.

Length 108, height 67, diam. 43 mm.

QUADRULA 831

Streams flowing into the Gulf of Mexico, from the Alabama
River west to eastern Texas; northward in the Mississippi
system to northwest Tennessee.

Type locality, Lake St. Joseph. La.

Unio crassidens var. a, LAMARCK, An. sans Vert., VI, 1819,
pazie

Plectomerus crassidens var. a, CONRAD, Pr. Ac. N. Sci. Phila.,
VI, 1853, p. 261.

Unio trapesoides Lea, Tr. Am. Phil. Soc., IV, 1831, p. 69, pl.
1, fig. 1; Obs., I, 1834, p. 70, pl. 1m, fig. 1—Hantey, Biv.
Shells, 1843, p. 176, pl. xx11, fig. 29.—CHENU, Ill. Conch.,
1858, pl. x, figs. 2, 2a, 2b; Manual, 1859, II, p. 142, fig. 690.
—Kuster, Conch. Cab., 1862, p. 274, pl. xct1, fig. 2—REEVE.
Conch. Icon., XVI, 1864, pl. v, fig. 17.

Margarita (Unio) trapezoides Lea, Syn., 1836, p. 12; 1838,
pi 34.

Margaron (Unio) trapezoides Lea, Syn., 1852, p. 21; 1870,
Piost:

Quadrula trapezoides SIMPSON, Syn., 1900, p. 772.

Crenodonta trapezoides ORTMANN, Ann. Car. Mus., VIII,
1912, p. 248, figs. 5-5a.

Unio interruptus Say, Transylvania Journal, IV, 1831, p. 525;
Am. Conch., IV, 1832, pl. xxx111.—CHENU, Bib. Conch., 1st
ser., ITI, 1845, p. 45, pl. xvu, figs. 1-3.

Unio dombeyana VALENCIENNES, Rec. Obs. Zool., II, 1833, p.
227, Ol. El. eS. IY. 1d, 10:

Ouadrula heros dombeyana Vanatra, Naut., XXIII, 1910,
Pp. FO2:

The only number of the section with purple, red or coppery
nacre.

Var. pentagonoides FRIERSON.

“This shell differs from the type in having its dorsum very
much arched or bent midway. The posterior is widely bian-
gulated. The anterior is singularly truncated like U. corus-
cus Gld. The effect being that the outline forms nearly an
equilateral pentagon, hence the name. Aside from its form,

832 QUADRULA

it differs in being much smaller and frequently entirely devoid
of plication on either its sides or posterior slope. A striking
peculiarity is that the posterior end of the ligament is per-
pendicularly over the centre of the base, whereas in the ordi-
nary trapezoides the end is situated about three-fourths of the
distance from the anterior to the posterior.” (Frierson).
Type locality, Calcasieu River, La.
Ouadrula trapezoides var. pentagonoides Frierson, Naut.,
XVI,. 1902, p. 40.

Section QUADRULA Ss. Ss.

Shell rhomboid, surface pustulous, with a high, rounded or
sharp posterior ridge; epidermis generally smooth and bright.
Type, Unio-cylindricus Say.

Group of Ouadrula metanevra.

Shell quadrate or rhomboid, with a wide, rounded posterior
ridge, above which, on the posterior slope, is a decided radial
furrow ; whole surface except the anterior end generally pus-
tulous, the sculpture of the posterior slope being often wrin-
kled; umbonal region high; epidermis shining, usually painted
with a beautiful pattern of triangular spots, and sometimes
chevron-shaped lines; hinge strong, the secondary lateral in
right valve rather feeble, but there is often a faint third lateral
above ; cavity of the beaks deep and compressed.

Animal with the marsupium filling all four leaves of the
branchie, the ova giving it a purplish tint ; inner gills free from
the abdominal sac for the greater part of their length; mantle
bordered with black; branchial opening: opposite the lobe of
the shell, extending well on to its base; anal opening without
papille.

QUADRULA CYLINDRICA (Say).
Shell much elongate, inflated and having parallel dorsal and

ventral lines so that it is almost cylindrical, inequilateral, solid ;
beaks rather full and elevated, turned forward over a deep.

QUADRULA 833

wide lunule, their sculpture a few irregular, strong ridges that
are nodulous on the posterior ridge; posterior ridge full,
rounded; above it there is usually a wide, radial impression
that sometimes ends in a slight sinus behind; anterior end
rounded, subangular above; posterior end squarely or oblique-
ly truncate; sometimes there is a point behind below the me-
dian line; surface with irregular, concentric sculpture, having
a row of knobs extending along the posterior ridge and often
more or less covered with lachrymous nodules and plications ;
epidermis straw-color, tawny, yellowish-green or greenish-yel-
low, generally overlaid with a pattern of triangular, green
blotches, these are sometimes developed into radial stripes as
if they had been painted on and had drizzled down; sometimes
the green blotches are so close that they are only separated by
narrow, greenish-yellow, zigzag lines, the whole smooth and
somewhat shining; pseudocardinals radially split up; laterals
long and straight ; anterior scars impresed; beak cavities deep,
compressed; nacre silvery white, rarely purplish, iridescent
and much thinner behind.

Length 114, height 50, diam. 46 mm.

Entire Ohio, Cumberland, and Tennessee river systems;
west to Nebraska (Aughey, doubtful) ; south to Arkansas and
Indian Territory.

Type locality, Wabash River.

Umio cylindricus Say, Nich. Encyc., I, 1817, pl. 1v, fig. 3.—
HitpretH, Am. Jl. Sci, XIV, 1828, p. 283, figs. 13, 13b.—
HANLEY, Biv. Shells, 1843, p. 182, pl. xx, fig. 31—KusTEr,
Conch. Cab. Unio, 1861, p. 194, pl. Lx, figs. I, 2—SOwER-
By, Conch. Icon., XVI, 1867, pl. Lx, fig. 300—Catu, Tr.
ead. Set, St. ous, Vil, 895, p:-15,-pl. x11.

Margarita (Unio) cylindricus Lea, Syn., 1836, p. 17; 1838, p.
10.

Margaron (Unio) cylindricus Lea, Syn., 1852, p. 23; 1870, p.
35:

Orthonymus cylindricus Acassiz, Arch. fiir. Naturg., I, 1852.
p. 48.

Mya cylindrica Eaton, Zool. Text-Book, 1826, p. 210.

834 QUADRULA

Unio (Theliderma) cylindrica SwAINson, Treat. on Mal., 1840,
pe 27 tig 5 4c.

Quadrula cylindrica SIMPSON, Syn., 1900, p. 773.

Unio (Eurynia) solenoides var. cylindrica RAFINESOUE, Ann.
Gen. Sci. Phys.’ Brux., V, 1820; p. 208.

Umio nawiformis LAMARCK, An. sans Vert., VI, 1819, p. 75.—
VALENCIENNES, Rec. Obs. Zool., IJ, 1833, p. 233, pl. Lut,
fig. 4.—Rreve, Conch. Syst., 1841, p. 118, pl. Lxxx1x, fig. 7.

Umo rugosus CHENU, Man., 1859, II, p. 138, fig. 668.

This is perhaps the most beautifully painted Naiad in the
world. Occasional specimens are uniformly colored, but a
great majority have a lovely pattern of green angular markings
on a lighter ground. The form is an aberrant one and can
never be mistaken for any other.

Mr. BR. H. Wright, Nautilus, XII, 1898, p. 6, has made a
var. strigillatus of a compressed, very rough form of cylindrica.
There seems to me to be an absolute graduation from cylin-
drical, nearly smooth specimens to this form.

QUADRULA METANEVRA Rafinesque.

Shell irregularly rhomboid, more or less inflated, solid, in-
equilateral; beaks rather full and high, turned forward over
a narrow lunule, their sculpture a few strong, irregular ridges,
which are nodulous on the posterior ridge; posterior ridge ele-
vated. rounded, separated from the rest of the shell in front
and behind by a radial depression; anterior end rounded ; base
line straight or incurved behind the middle; dorsal slope ob-
liquely truncated, the sulcation above the posterior ridge end-
ing in a well-marked sinus; surface more or less covered with
lachrymose knobs or tubercles, a row on the posterior ridge
usually higher; epidermis yellow-green, tawny or brownish,
often marked with small, dark green, triangular patches, sub-
shining to dull and rough; pseudocardinals ragged, two in the
left valve and three in the right; laterals short ; anterior scars
small, impressed ; beak cavities deep, compressed ; nacre white,
rarely pinkish, greatly thickened at the anterior base.

Length 100, height 72, diam. 55 mm.

QUADRULA 835

Mississippi drainage area except its southern portion, ex-
tending to the Tennessee and Arkansas rivers.

Type locality, Kentucky River.

Obliquaria (Quadrula) metanevra RAFINESQUE, Ann. Gen.
oci., Brux., V, 1820, p. 305, pl. LXxXI, figs. 15, 16—CHENU,
Bibs Conch. tseser., [Ll 1845) -p. 18; pl. 11, fig. 15; 16.

Unio (ITheliderma) metanevra SwAINson, Treat. on Mal.,
1840, p. 268, figs. 50, 540.

Quadrula metanevra SIMPSON, Syn., 1900, p. 774.—ORTMANN,
Ann. Car. Mus., VIII, 1912, p. 255, figs. 6-6a.

Unio metanever HAN Ey, Biv. Shells, 1843, p. 179, pl. xx1,
fig. 31.—Rereve, Conch. Icon., XVI, 1864, pl. vir, fig. 25.
Margarita (Unio) metanever Lia, Syn., 1836, p. 15; 1838, p.

15.

Unis metanevrus CONRAD, Monog., I, 1835, p. 10, pl. v, fig. 2.
=Car, It Acad. N. Sci. St. Lots, VII, 1895, p. 28, pl. x.

Margaron (Umo) metanevrus Lea, Syn., 1852, p. 22; 1870, p.

Unie metaneurus Kuster, Conch. Cab. Unio, 1852, p. 50, pl. x,
fig. 4.

? Unio nodosus Barnes, Am. Jl. Sci., VI, 1823, p. 124, pl. v1,
figs. 7, 7a, 7).—CuENu, Manual, 1859, II, p. 138, fig. 663.

Mya nodosa Katon, Zool. Text-Book, 1826, p. 216.

A solid, rhomboid form usually covered with tear-like tu-
bercles and having stronger knobs on the rounded posterior
ridge. ‘The smaller forms run suspiciously close to Q. tuber-
osa.

Var. wardu (Lea).

Shell more compressed, more delicate and less solid than the
type, usually smoother, sometimes scarcely tuberculate.

Ohio ; west to Iowa.

Type locality, Walhonding River, Ohio; Wassepinicon Riv-
er, lowa; Coal River, Logan Co., Va.

Unio wardi Lea, Pr. Ac. N. Sci. Phila., V, 1861, p.-392; Jl.
mc Ns sci. Phila. 2-12. p s7,.pl. xxiv, fig. 257; Obs.,
IX, 1863, p. 9, pl. xxiv, fig. 257——SowerpBy, Conch. Icon.,
XVI, 1868, pl. txxxt1, fig. 434.

Margaron (Unio) wardiit Lea, Syn., 1870, p. 33.

836 QUADRULA

Ouadrula metanevra var. waydu SIMPSON, Syn., 1900, p. 774.
This form is about as well separated from typical metanevra
as is tuberosa. ‘There are intermediates, which completely con-
nect the variety with the species. The typical wardii is a

trifle more elongated than the average metanevra.

QUADRULA TUBEROSA (Lea).

Shell irregularly subrhomboid, solid, subinflated, inequi-
lateral ; beaks high, rather full; lunule small or almost wanting ;
anterior end rounded; base line rounded, generally emarginate
in front of the posterior ridge; dorsal slope truncated obliquely,
with a sinus above the posterior ridge and an angle where the
truncation joins the dorsal line; posterior ridge elevated,
rounded. with a shallow radial depression in front of it and
a deeper one behind it; surface, except the anterior end, cov-
ered with irregular, elevated tubercles ; epidermis tawny, tawny-
greenish or brown, often having faint, triangular, green mark-
ings, dull colored; pseudocardinals radial, marked with radial
striz ; laterals short, that of the right valve double; beak cav-
ities deep, compressed ; nacre white, thin and iridescent behind.

Length 60, height 60, diam. 32 mm.

Length 56, height 46, diam. 25 mm.

Cumberland and Tennessee River systems.

Type locality, Caney Fork and Cumberland rivers, Tenn.
Unio tuberosus Lea, Pr. Am. Phil. Soc., I, 1840, p. 286; Tr.

Am. Phil. Soc., VIII, 1842, p. 210, pl. xiv, figy 25; Obs.,

TIT, 1842, p. 48, pl. xiv, fig. 25—Cuenu, Hl. Conch., 1858,

pl. xxvii, hies:*7, 7¢,°70:

Margaron (Unio) tuberosus LEA, Syn., 1852, p. 22; 1870, p. 33.
Ouadrula tuberosa SIMPSON, Syn., 1900, p. 774.

Generally a little shorter in proportion than metanevra, not
knobbed on the posterior ridge, smaller, less brightly painted
and having a more decided projection of the posterior ridge.
‘he lateral of the right valve is more completely double than

it is in metanevra.

QUADRULA 8

ios)
“I

Var. sparsa (Lea).

Shell smaller than twberosa, generally not nodulous.

Length 47, height 38, diam. 22 mm.

Holston and Clinch rivers, Tennessee.

Type locality, Holston river, Tennessee.

Umo sparsus Lea, Pr. Am. Phil. Soc., II, 1841, p. 82; Tr. Am.
Phi ode. UL, 1642, p:-242, pl xxv, fig. 58; Obs., ITT,
1842, p. 80, pl. xxv, fig. 58—CHENU, Ill. Conch., 1858, pl.
XXVI, figs. 2, 2a, 2b.—RreEveE, Conch. Icon., XVI, 1864, pl.
IV, fig. 14.

Margaron (Umio) sparsus Lea, Syn., 1852, p. 22; 1870, p. 33.

Quadrula sparsa SIMPSON, Syn., 1900, p. 775.

After critically comparing large series of this and tuberosa,
it does not seem to me that it can take any higher rank than
that of a variety of the latter. It is smaller and generally a
little less nodulous, but the coloring, texture, form and general
characters are practically the same. I am very strongly in-
clined to believe that both should be considered mere varieties
of metanevra.

QuADRULA INTERMEDIA (Conrad).

Shell subelliptical, suborbicular or subquadrate, convex to
subinflated ; beaks moderately high but not full; posterior ridge
scarcely elevated above the outline of the shell, but having
above it a deep, wide, radial depression, so that on its upper
side it is well defined; the depression ends in a deep, rounded
sinus: surface covered, except on the anterior end, with large,
elevated warts, which are sometimes double; epidermis green-
ish-yellow or yellowish-green, variegated with fine, angular
green spots or zigzags, sometimes with imperfect rays; pseu-
docardinals radial, radially striate; lateral of right valve dou-
ble; beak cavities deep, much compressed ; muscle scars small,
impressed; nacre white or straw-color, thinner and iridescent
behind.

Length 59, height 51, diam. 29 mm.

Tennessee River system.

Type locality, Nolachucky River, Tenn.

$38 QUADRULA

Unio mtermedius CONRAD, Monog., VII, 1836, p. 63, pl. xxxv,
fig. 2—Han.ey, Biv. Shells, 1856, p. 381, pl. xx, fig. 28.—
Kuster, Conch. Cab. Unio, 1861, p. 213, pl. Lxx, fig. 6.—
REEVE, Conch. Icon., XVI, 1864, pl. x11, fig. 48.

Margaron (Unio) intermedius Lea, Syn., 1852, p. 22; 1870,
D. 33:

Quadrula intermedia SIMPSON, Syn., 1900, p. 775.

Unio kleinianus Kusver, Conch. Cab. Unio, 1861, p. 191, pl.
EX, ea As
More compressed and lenticular, more nearly round or short

elliptical than tuberosa, to which it sometimes closely approach-

es. The posterior radial depression is deeper and more sin-
uate behind than in any member of the group and the posterior
ridge is less elevated or produced below.

QUADRULA STAPES (Lea).

Shell irregularly quadrate, subinflated to inflated, solid, equi-
lateral; beaks high but not very full; posterior ridge high,
narrowly rounded or subangular, behind it there is a radial
depression and the posterior end of the shell is decidedly trun-
cated: anterior end rounded; base rounded, straight behind,
sometimes slightly incurved in front of the posterior ridge; .
surface covered with warts or lachrymose tubercles; these
are sometimes triangular or formed into broken, zigzag
ridges; epidermis yellowish-green in the young shells with
fine, zigzag or triangular green markings; old shells usually
brown; pseudocardinals radial, ragged; laterals short, that
of the right valve double; beak cavities deep, compressed ;
muscle scars small, impressed; nacre silvery white, thinner and
iridescent behind.

Length 60, height 53, diam. 27 mm.

Length 49, height 44, diam. 36 mm.

Alabama and Tombigbee rivers.

Type locality, Alabama river.

Umo stapes Lea, Tr. Am: Phil. Soc. 1V, 1831, p- 77, pl. vil,
fig. 8; Obs., I, 1834, p. 87, pl. vu, fig. 8—Conrap, Monog.,
VII, 1836, p. 62, pl. xxxv, fig. 1—HANtEy, Biv. Shells,
1843, p. 179, pl. xxi, fig. 38.—CueEnu, Ill. Conch., 1858, pl.
XV, figs. 5, 5a, 5b; Manual, 1859, II, p. 142, fig. 997.—
Reeve, Conch. Icon., XVI, 1864, pl. x11, fig. 52.

QUADRULA 839

Margarita (Unio) stapes Lea, Syn., 1836, p. 15; 1838, p. 13.
Margaron (Unio) stapes Lea, Syn., 1852, p. 22; 1870, p. 33.
Quadrula stapes SIMPSON, Syn., 1900, p. 775.

Unio retusus Say, Am. Conch., VI, 1834.

Unio stegarius Kuster, Conch. Cab. Unio, 1861, p. 211, pl.

Lexy Ho.

In this species the beaks are placed usually midway between
the anterior and posterior ends, sometimes a little in front
of the center and occasionally just behind it. The shell is
almost as decidedly truncate behind as is that of Plagiola ele-
gans. ‘These two characters will distinguish it from all other
related forms.

Section THELIDERMA (Swainson, 1840) Simpson.

Theliderma Swainson, Treat. Mal., 1840, p. 378.—SiMpsoN,

Syn., 1900, p. 775.

Shell rounded, quadrate to rhomboid, solid, inflated; beaks
rather prominent; beak sculpture consisting of a few rather
coarse, subparallel ridges; anterior end rounded or slightly
subtruncate above; base often arcuate; posterior end truncate,
high, angled behind the ligament; epidermis scarcely rayed,
never painted ; beak cavities rather deep.

Type, Unto lachrymosus Lea.

Group of Quadrula lachrymosa.

Shell quadrate or rhomboid, generally with a sharp, well-
developed posterior ridge, in front of which 1s a wide, shallow,
radial excavation; base incurved; posterior end sharply trun-
cate, generally slightly biangular below, high and distinctly
angled behind the ligament; posterior tubercles often in some-
what radiating rows; earlier beak sculpture consisting of
ridges nearly parallel with the growth lines; but later on be-
coming doubly looped and blending into the general sculpture
of the shell; epidermis smooth; pseudocardinals strong: lat-
erals straight; nacre white.

840 QUADRULA

Animal with all four gills used as a marsupium throughout,
inner much the larger, free from the abdominal sac nearly or
quite their whole length; palpi very large; branchial opening
generally having clustered, often branching, papille; anal
opening smooth; superanal opening closed below.

(QUADRULA ASPERA (Lea).

Shell subrhomboid, moderately inflated, subsolid to solid,
somewhat inequilateral; beaks high, rather full, their sculpture
a number of strong, somewhat double-looped ridges, which
gradually blend into the sculpture of the surface; posterior
ridge well-developed, distinctly double and angled, ending at
the base oi the shell in a decided biangulation; in front of it
there is a wide radial depression and there is often another be-
hind it, the outline of the shell being incurved where these
depressions end; anterior end rounded, slightly, obliquely trun-
cate above; base line incurved in front of the posterior ridge;
post-dorsal slope often curved, sometimes raised to an angle
behind the ligament; surface more or less covered with coarse
and fine pustules, which are often longitudinally compressed,
they are frequently stronger in the anterior post-ridge and
down the middle of the disk ; the depressed area between being
smoother ; epidermis lurid greenish to brown, scarcely shining ;
pseudocardinals radial, radially striate and often much split;
laterals curved, that in the right valve somewhat double ; ante-
rior scars deep, partly filled with rough nacre; beak cavities
moderately deep; nacre whitish, iridescent behind.

Length 63, height 50, diam. 30 mm.

Length 7o, height 47, diam. 30 mm.

Length 56, height 47, diam. 27 mm.

Streams flowing into the Gulf of Mexico from Alabama
west to central ‘l‘exas, and northward to the Verdigris river,

Kansas.

Type locality, Alabama river.

Unio asper Lea, Tr. Am. Phil. Soc., IV, 1831, p. 85, pl. 1x, fig.
15; Obs., I, 1834, p. 95, pl. rx, fig. 15.—HANLEy, Biv. Shells,
1843, p. 179, pl. xxu, fig. 37—CuENu, Ill. Conch., 1858, pl.
XV, figs. 4, 4a, 4b; Manual, 1859, II, p. 142, fig. 695.—REEvE,
Conch. Icon. XVI, 1864, pl: vee 16.

QUADRULA 841

Margarita (Unio) asper Lea, Syn., 1836, p. 15; 1838, p. 15.
Margaron (Unio) asper Lma, Syn., 1852, p. 22; 1870, p. 33.
Quadrula asper SIMPSON, Syn., 1900, p. 776.

Quadrula aspera OrtMANN, Ann. Car. Mus., VIII, 1912, p.
253;

Unio turgidus Reeve, Conch. Icon., XVI, 1864, pl. 11, fig. 10.
Unio apiculatus var. asper Payren, Conch. Sam., III, 1890, p.

144.

Variable in size, form, tuberculation and smoothness of epi-
dermis, and very closely related to several other forms. Some
specimens are almost smooth with the exception of the rows
of strong tubercles on the median and posterior ridges, and
approach dangerously close to forms of what I believe are
lachrymosa. On the other hand certain shells are quite densely
tuberculate and approach very near to apiculata.

QUADRULA LACHRYMOSA (Lea).

Shell subrhomboid, subinflated, solid, somewhat inequilat-
eral; beaks high and full, their sculpture doubly looped or
zigzagged bars, with radial threads behind them; posterior
ridge well developed, generally somewhat double, ending at
the base of the shell in a feeble biangulation; in front of and
behind it there is a wide, radial depression; anterior end
rounded; base line incurved in front of the posterior ridge;
posterior end squarely or somewhat obliquely truncated, with a
sinus in the middle; at the middle of the shell or a little in
front of it there is usually a wide radial swelling ; surface gen-
erally more or less covered with tubercles, excepting in front
of this ridge; the sculpture on this and the posterior ridge
often stronger than elsewhere; epidermis greenish in young
shells, greenish-brown, brown or tawny in old ones, usually
somewhat shining, sometimes feebly rayed; pseudocardinals
very strong, triangular, ragged: lateral of the right valve
somewhat double; anterior scars well impressed ; beak cavities
moderately deep; nacre white, thinner and iridescent behind ;
pallial line deep, roughened, remote in front.

Length 143, height 110, diam. 63 mm.

Length 100, height 88, diam 50 mm.

842 QUADRULA

Iintire Mississippi river drainage; various localities in the
St. Lawrence basin; Red River of the North; southwest into
eastern Texas.

Type locality, Ohio.

Unio lachrymosus Lea, Tr. Am. Phil. Soc., III, 1828, p. 272,
pl. v1, fig. 8; Obs., I, 1834, p. 14, pl. vi, fig. 8 —Han ey, Biv
Shells, 1843, p. 177, pl. xx, fig. 38.—Kuster, Conch. Cab.,
1854, p. 70, pl. xv, fig. 3—CneEnu, Ill. Conch., 1858, pl.
xv, figs. 6, 6a, 6b; Manual 1849, II, p. 142, fig. 698.— REEVE,
Conchs Icon: 20V, 1864, pl nie tie 333?

Margarita (Unio) lachrymosus Lea, Syn., 1836, p. 14; 1838,
De 15:

Margaron (Unio) lachrymosus Lea, Syn., 1852, p. 21; 1870,
pase:

Quadrula lachrymosa BAKER, Moll. Chicago, Pt. I, 1808, p. 83,
pl. xxv, fig. 1; xu, fig. 2—SIMPSON, Syn., 1900, p. 776.
Unio asperrimus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 71, pl-

v, fig. 3; Obs., I, 1834, p. 81, pl. v, fig. 3—-HANLEy, Biv.

Shells, 1843, p. 178, pl. xx1, fig. 12—Potigz and MicHaAup,

Gall. Moll., 1844, p. 156, pl. tix, figs. 2, 3—CuHeEnu, III.

Conch., 1858, plo 1x, figs. ©, ta, vb.

Margarita (Unio) asperrimus LEA, Syn., 1836, p. 14; 1838, p.
WS:

Margaron (Unie) asperrimus Lea, Syn., 1852, p. 21; 1870, p.
33.

Unio quadrulus Say, Am. Conch., VI, 1834.—KustrEr, Conch.
Cab., 1861, p7184, plivin, tie. 1:

Unio quadratus REEVE, Conch. Icon., XVI, 1864, pl. vr, fig. 24.
Abundant, widespread and variable. Specimens occur,

which are almost without tubercles, others are almost entirely

covered with them. Those on the central ridges are often
elongated in the direction of the growth lines, while the ones
on the posterior ridge are rounded.

QUADRULA COUCHIANA (Lea).

Shell of medium or rather small size, subrhomboid, subin- |
flated, rather solid, slightly inequilateral; beaks full and ele-
vated, their sculpture consisting of strong doubly-looped or

QUADRULA 843)

zigzag ridges: posterior ridge moderately developed, generally

double, and indistinctly angled, ending at the base of the shell

in a biangulation; in front of and behind it there is a slight
radial depression; there is usually a more or less developed,
median, radial elevation; surface with fine, concentric growth
lines, otherwise nearly smooth or covered with scattered pus-
tules; epidermis greenish in the young shell, ashy-brown in
the adult; pseudocardinals elevated, ragged and uneven; lat-
eral of the right valve single or slightly double; beak cavities
moderately deep; muscle scars impressed; nacre white, often
silvery and iridescent behind.

Length 50, height 38, diam. 26 mm.

Length 41, height 30, diam. 20 mm.

Type locality, Rio Salado, New Leon, Mexico. Also south-
western Texas.

Umio couchianus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 305;
jieAc oN oct: Piila LV. Tsbo; peis7t, (pl. UxXVie-he. TOO:
Obs., VIII, 1860, p. 53, pl. xvi, fig. 196—Sowersy, Conch.
Teons XV I, 1868; pl. uxxxi, fig. 420.

Margaron (Unie) couchianus Lea, Syn., 1870, p. 54.

Ouadrula couchiana SIMPSON, Syn., 1900, Pp. 777.
lea has in his collection two matched pairs of this form,

which are almost smooth. Other shells received from Dr.

Mearns from the southwestern part of the state are more or

less covered with scattered nodules. It is a rather small,

somewhat elongated species having an ashy-brown epidermis.

QUADRULA FRAGOSA (Conrad).

Shell short, irregularly quadrate, inequilateral, subinflated,
solid; beaks very high, full, turned forward over a well-de-
veloped lunule; anterior end rounded; base line incurved in
front of the posterior ridge; posterior end almost squarely
truncated ; posterior ridge single above, double below, with a
radial depression in front of and behind it; surface with un-
even, concentric growth lines; anterior third of the shell other-
wise smooth; remainder of the shell having coarse, scattered,
irregular tubercles, which are strongest on the posterior and

844 QUADRULA

median ridges; epidermis brownish, not shining ;. pseudocar-

dinals elevated, exceedingly ragged and torn; lateral of the

right valve usually single; beak cavities deep, compressed;
anterior scars small; nacre white, thinner and slightly irides-
cent behind.

Length 96, height 85, diam. 53 mm

Ohio, Cumberland, and Tennessee river systems; westward
probably to Minnesota, Nebraska, and Kansas.

Type locality, Scioto River, Ohio.

Unio fragosus Conrap, Monog., II, 1836, p. 12, pl. v1, fig. 2.—
Kuster, Conch. Cab. Unio, 1861, p. 173, pl. Lv, fig. 1.—
Reeve, Conch. Icon., XVI, 1864, pl. 1, fig. 2; pl. vu, fig. 27.

Margarita (Umno) fragosus Lea, Syn., 1836, p. 14; 1838, p. 15.

Margaron (Unio) fragosus LEA, Syn., 1852, p. 22; 1870, p. 33.

Unio fragosa CatLow and Reve, Conch. Nom., 1845, p. 59.

Quadrula fragosa SIMPSON, Syn., 1900, p. 778.

Unio tragosus HANLEY, Biv. Shells, 1843, p. 178, pl xx, fig. 4o.
A robust, rude, short quadrate species with strong tubercles,

which sometimes are knob-like on the posterior and median
ridges. The epidermis is brown, rayless and dull. It is gen-
erally much more quadrate than lachrymosa and has stronger
sculpture, though there are intermediate specimens that are
sometimes difficult to place.

QUADRULA FORSHEYI (Lea).

Shell rather short, subquadrate, subinflated, nearly or quite
equilateral, solid; beaks elevated but not inflated, their sculp-
ture sharply doubly-looped ridges; posterior ridge well de-
veloped, single above, double below, ending at the base of the
shell in a biangulation and having in front of and behind it
a radial depression; anterior end round; base line incurved
in front of the posterior ridge; posterior end almost squarely
truncated, with a sinus just above the termination of the poste-
rior ridge; surface with uneven growth lines, more or less
covered throughout with rather small tubercles; epidermis
greenish in young shells, brownish or ashy-brown in old ones ;
pseudocardinals strong, triangular, not greatly torn; lateral

QUADRULA 845

of the right valve somewhat double; beak cavities deep, com-

pressed; muscle scars impressed; nacre whitish, thinner and

slightly iridescent behind.

Length go, height 80, diam. 47 mm.

Alabama to Texas, in streams flowing into the Gulf of
Mexico. |

Type locality, Fayette Co., Texas.

Umo forsheyi Lwa, Pr. Ac. N. Sci. Phila., III, 1859, p. 155;
i Ac, Nose Phila. 9 V, re60, p. 357, pl. Lx, fig. 182; Obs.,
VIII, 1860, p. 39, pl. Lx, fig. 182—RerEve, Conch. Icon.,
XVI, 1864, pl. vi, fig. 21.

Margaron (Unic) forsheyt Lea, Syn., 1870, p. 32.

Ouadrula forsheyi StMPSON, Syn., 1900, p. 778.

This species varies much in the degree of smoothness or
roughness of its surface. Young specimens are more tuber-
culous than old ones. The tubercles usually extend over the
whole surface and in this it differs from the ordinary mani-
festation of /achrymosa and fragosa where they are usually
wanting on the anterior end. I am inclined to think that it
may run into Q. speciosa.

QUADRUILA SPECIOSA (Lea).

Shell long rhomboid or long quadrate, subcompressed, in-
equilateral, subsolid; beaks rather high but not full, their
sculpture sharply doubly-looped ridges; posterior ridge single
and angled above, becoming double below, ending in a bian-
gulation at the base of the shell; in front of and behind it
there is a faint radial depression; surface densely covered with
rather small, uneven pustules, which are arranged on the pos-
terior slope in curved, subradial lines; epidermis greenish ;
pseudocardinals elevated, two in the left valve and one with
two vestigial ones in the right; left valve with two laterals;
right valve with one double one; beak cavities rather deep,
compressed; anterior scars impressed, rough; nacre bluish-
white, silvery.

Length 62, height 45, diam. 20 mm.

Kansas, south to Texas.

846 QUADRULA

Type locality, Colorado River, La Grange and Leon Co.,
dexas:

Unio speciosus Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 168;
jl. Ac. N. Sex Phila, V,) 1622p: 207, ipl sxe, ic pees
Obs., IX, 1863, p. 29, pl. xxx1, fig. 276.—SoweErsBy, Conch.
Icon., XVI, 1868, pl. LXxxIv, fig. 447.

Margaron (Unio) speciosus Lea, Syn., 1870, p. 33.

Quadrula speciosa SIMPSON, Syn., 1900, p. 778.

Lea has four shells in his collection labeled Unio speciosus.

I have given above the measurements of the largest one

and am doubtful whether any of them are adult. ‘They are

very much like young forsheyi, but are more compressed and
elongated.

QUADRULA APICULATA (Say).

Shell subrhomboid, rather short, slightly inequilateral, sub-
solid to solid; beaks high, moderately full; posterior ridge well
developed, narrowly rounded, angled or showing a tendency
to be double, ending in a point or feeble biangulation at the
base of the shell; in front of and behind it there are radial
depressions ; anterior end rounded, sometimes obliquely trun-
cated above; basal line sinused in front of the posterior ridge;
outline of dorsal slope raised to an angle behind the ligament,
squarely or obliquely truncate below; surface covered with
fine, close pustules, which are often laid down in zigzag pat-
terns; epidermis greenish in young shells, ashy-brown in old
ones, dull; pseudocardinals radial, somewhat split; lateral of
right valve partly double; beak cavities moderately deep; an-
terior scars well impressed: nacre white, iridescent behind.

Length 72, height 59, diam. 37 mm.

Length 60, height 52, diam. 32 mm.

Louisiana to Texas.

Type locality, New Orleans, La.

Unio apiculatus Sav, New Harm. Diss., II, No. 2, 1829, p. 309 ;
Am. Conch., VI, 1834, pl. L11—Conrap, Monog., IX, 1837,
p. 78, pl. xi1v, fig. 1—Hantey, Biv. Shells, 1843, p. 178, pl.
Xxill, fig. 51.—CHenu, Manual, 1850, II, p. 142, fig. 696.—
Reeve, Conch. Icon., XVI, 1864, pl. 1, fig. 11.

QUADRULA 847

Margarita (Unio) apiculatus Lea, Syn., 1836, p. 15): 1838, <p:
iit

Margaron (Unio) apiculatus Lea, Syn., 1852, p. 22; 1870, p.
33-

Quadrula apiculata Simpson, Syn., 1900, p. 778.

Unio nobilis Conrap (part), Jl. Ac. N. Sci. Phila., 1854, p.

267, Pls SORVin, Noy 2.

Close to aspera, but, as a rule, not quite as elongated. It
is more densely covered with pustules, which are often ar-
ranged in partly zigzag patterns, they are finer, and are equally
numerous in the radial depression in front of the posterior
ridge. Those on the posterior and median ridges are not en-
larged and the epidermis in mature specimens is more ashy-
colored and less brown than in aspera.

QUADRULA RUMPHIANA (Lea).

Shell subquadrate, subinflated, solid, equilateral or having
the beaks slightly nearer to the posterior end; beaks high,
moderately full; their sculpture consisting of sharply doubly
looped bars; posterior ridge full, rounded or showing a slight
inclination towards being biangulate, ending at the posterior
base of the shell, and having in front of and behind it a de-
cided radial depression ; anterior end round; base line incurved
in front of the posterior ridge; posterior end almost squarely
truncated, sinused above the posterior ridge; surface more or
less covered with low tubercles of various sizes, the posterior
ridge nearly or quite smooth; post-dorsal slope with radial,
nodulous plications; epidermis greenish in the young shell,
rich reddish-brown in the adult shell, shining; pseudocardinals
subtriangular, rough, but not much split; laterals short,
straight, that of the right valve more or less double; beak
cavities deep; muscle scars well marked; nacre silvery, thinner
and iridescent behind.

Length 90, height 78, diam. 45 mm.

Type locality, Western Georgia. Also Alabama in the Gulf

drainage. the

848 QUADRULA

Unio rumphianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 276, pl.
xxi, fig) 347 Obs. .V; 2852) pa 32s plex, ie ae

Margaron (Unio) rumphianus Lea, Syn., 1852, p. 21; 1870, p.
33:

Quadrula rumphiana SIMPSON, Syn., 1900, p. 778.

Unio blandianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p.
203; Jl Ac ON. Set. Phila. TV, 1858) p65, cpiexiaioael ye
Obs., VI, 1858, p. 65, pl. x1, fig. 47—Sowerry, Conch. Icon.,
XVI, 1868, pl. Lxxvitl, fig. 405.

Margaron (Unio) blandianus Lea, Syn., 1870, p. 33.

A very fine species with generally smooth, somewhat round-
ed posterior ridge and rich shining brown epidermis. The
nacre is fine and silvery. I have seen specimens, which I re-
ferred to this species with doubt, that have quite strong, rough
pustules.

Group of Quadrula pustulosa.

Shell round quadrate, truncated behind, full and angled
back of the ligament; beaks high; beak sculpture a few coarse
ridges, which are swollen at the posterior ridge, which is
rounded; surface generally more or less pustulous, but some-
times entirely smooth, and in some cases slightly corrugated ;
epidermis often having broad, faint, green rays; hinge strong ;
nacre white or purple.

Animal with the marsupium occupying all four gills
throughout; inner gills the larger, free the whole or the
greater part of their length from the abdominal sac ; branchial
opening having clustered, often branching papille.

QUADRULA PUSTULOSA (Lea).

Shell subquadrate, subrhomboid, subtriangular or suborbic-
ular, generally inflated, solid, inequilateral; beaks full and
high, turned forward over a deep lunule, their sculpture a few
coarse corrugations; anterior end rounded; base straight or
lightly curved; posterior end squarely or obliquely truncated,
usually well-angled behind the ligament; posterior ridge only
moderately developed, rounded; there is often a slight radial

QUADRULA 849

depression above it; surface, excepting at the anterior part,

usually more or less covered with warty or lachrymose tuber-

cles, sometimes nearly or quite smooth; epidermis tawny or
tawny-greenish in young shells, often with a wide, broken,
bright green ray, dirty brownish in old shells ; pseudocardinals
strong, triangular, more or less ragged, two in the left valve
and three in the right; lateral of the right valve sometimes
partly double; beak cavities deep, compressed; muscle scars
impressed ; nacre white, thinner and iridescent behind.

Length 105, height 95, diam. 70 mm.

Length 75, height 72, diam. 40 mm.

Length 56, height 51, diam. 35 mm.

Entire Mississippi drainage; Michigan; Lake Erie.

Type locality, Ohio; Alabama river.

Unio pustulosus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 76, pl.
vil, fig. 7; Obs., I, 1834, p. 86, pl. vir, fig. 7—HAnN Ley, Biv.
Shells, 1843, p. 180, pl. xx, fig. 34.—CneEnu, III. Conch.,
LQ5O. pl, XXIU, oes..2,. 20. 2b.

Margarita (Unio) pustulosus Lea, Syn., 1836, p. 15; 1838, p.
1S.

Margaron (Unio) pustulosus Lea, Syn., 1852, p. 22; 1870, p.
33.

Ouadrula pustulosa BAKER, Moll. Chicago, Pt. 1, 1898, p. 86,
pl. xxv, fig. 2; xxvu, fig. 13.—Srmpson, Syn., 1900, p. 779.

Unio verrucosa VALENCIENNES, Rec. Obs. Zool. Anat., II,
Lege Sale pk Litt, figs 2.

Unio nodulosus Say, Am. Conch., VI, 1834.

Unio prasinus Conrap, New F. W. Shells, 1834, p. 44, pl. 311,
fig. 1; Monog., TX, 1837, p. 790, pl. xiv, fig. 2—CHENU, Bib.
Gonch:; -ist\ ‘ser; TL, 2845; p: 22;-pl. 10,. fig: 1.—REEvE,
Conch. Icon., XVI, 1864, pl. vir, figs. 26, 26a, 26D.

Unio bullatus var. prasinus Pavrer, Conch. Sam., III, 1890, p.
146.

Unio bullatus Conrap, New F. W. Shells, 1834, p. 68; Monog.,
X, 1838, p. 82, pl. xiv, fig. 2—Kusrer, Conch. Cab. Unio,
1852, p. 47, pl. tx, fig. 3—Rreve, Conch. Icon., XVI, 1864,
pl. x11, fig. 2.

850 QUADRULA

Unio dorfeuillianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 73,
pl. xvii, fig. 54; Obs., II, 1838, p. 73, pl. xvu, fig. 54.—Han-
LEY, Biv. Shells, 1843, p. 179, pl. xxu111, fig. 10.—CHENU, IIl. -
Conch., 1858, pl. xxv, figs. 5, 5a, 5b.—Rereve, Conch. Icon.,
XVI, 1864, pl. x, fig. 38.—Cat (part), Tr. Ac. N. Sci., St.
Louis; Vil; 1895;"p: 40-pls) xan; XT AKIVs KV, tess Tees

Margarita (Unio) dorfeuillianus Lea, Syn., 1838, p. 15.

Margaren (Unio) dorfemlianus Lea, Syn., 1852, p. 22; 1870,
P. 33-

Unio uber Conrap, Am. Jl. Conch., II, 1866, p. 270, pl. xv, fig.
10:

Abundant throughout the most of the Upper Mississippi
drainage and very variable. The anterior one-fourth to two-
fifths of the surface is usually smooth, the remainder is gener-
ally furnished with various sized pustules, though in some cases
the whole shell is destitute of tubercles. A large quadrate
shell with high beaks from the Wabash was called Unio dor-
fenillianus by Dr. Lea, but it scarcely differs from shells, which
he has placed with his pustulosus. Two of the specimens he
has placed with dorfeuillianus are from Columbus, Mississippi,
and are certainly Q. mortoni Conrad.

Var. schoolcraftensis (Lea).

More quadrate and compressed than the type, the young us-
ually with a broad, often broken, ray in the middle of the disk
with narrow ones on the dorsal slope; surface varying from
smooth to pustulous. It is distributed over much the same
area as the type.

Length 72, height 64, diam. 35 mm.

Mississippi valley.

Type locality, Fox River of Green Bay.

Unio schoolcraftensis Lea, Tr. Am. Phil. Soc., V, 1834, p. 37;
pl. 1, fig. 9; Obs., I, 1834, p. 149, pl. 11, fig. 9.—SOWERBY,
Conch. Icon., XVI, 1868, pl. 1, fig. 3; pl. x1, fig. 47.

Margarita (Unio) schoolcraftensis Lea, Syn., 1836,. ps 25%
1838, p. 15.

Margaron (Unio) schoolcraftensis Lea, Syn., 1852, p. 22.

QUADRULA 851

Unio bullatus var. schoolcraftensis Payret, Conch. Sam., III,
1890, p. 146.
Margaron (Unio) schoolcraftu Liza, Syn., 1870, p. 33.
Unio schoolcraftu, B. H. Wricut, Check List, 1888.
Varies absolutely into the type, but possibly worthy of
varietal rank. ‘Che type was a young shell and is not in the
Tea collection.

Var. perncdosa (Lea).

Suborbicular, moderately inflated, pustulous ; epidermis yel-
lowish-brown.

Length 50, height 50, diam. 33 mm.

Tennessee and Alabama River systems.

Type locality, North Carolina.

Unio pernodosus Lea, Pr. Am. Phil. Soc., [V, 1845, p. 163;
daeAmaw ehal: ‘Sock, Xi 1848, pi 71, pl 11; fies 8 ;-Obs;5 LV,
1848, p. 45, pl. 1, fig. 8.—Rrrve, Conch. Icon., XVI, 1864,
ply sree his: 4G:

Margaron (Unio) pernodosus Lea, Syn., 1870, p. 34.

Ouadrula pustulosa var. pernodos@ SIMPSON, Syn., 1900, p.
780.

Unio asperatus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 41; Jl.
AGN voc enila. Vii i862, ps 6s, pl. vir, fig. 218 Obs;
VIII, 1862, p. 72, pl. vir, fig. 218.—Sowerpy, Conch. Icon.,
XVI, 1868, pl. Lxxxv, fig. 450.

Margaron (Unio) asperatus Lea, Syn., 1870, p. 33.
Distinguished from the type by being nearly orbicular in

outline. Specimens connecting it with the type are abundant

in the Chio and adjacent rivers.

Var. kieneriana (Lea).

Shell suborbicular, smooth or somewhat nodulous; epider-
mis ashy-brown or greenish-brown.

Length 39, height 39, diam. 22 mm.

Alabama river system.

Type locality, Coosawattee river, Murray Co., Ga.

852 QUADRULA

Unio keinerianus Lea, Pr. Am. Phil. Soc., V, 1852, p. 251;
Tr: Am. Phil; Soc. X; 1852, p.281, plax xt, se. 4aOwelps.
V, 1852, p. 37, pl. xx111, fig. 40.

Margaron (Unio) kemerianus L&A, Syn., 1852, p. 22.

Margaron (Unio) kienerianus Lea, Syn., 1870, p. 34.

Quadrula pustulosa var. keimeriana SIMPSON, Syn., 1900, p.
780.

Seems tc merge into variety pernodosa, but it is smaller
and the epidermis is differently colored. Some specimens have
broken green bands and are feebly rayed.

This form was named by Lea after Kiener, but he inad-
vertently misspelled the name. It is therefore proper to cor-
Tech tne eLLor.

QUADRULA COOPERIANA (Lea).

Shell subtriangular, rarely suborbicular, subinflated, solid,
inequilateral; beaks very high, rather full, turned forward
over a deep lunule; posterior ridge low, rounded; anterior
end usually obliquely truncated above, rounded below; base
line more or less rounded; outline of dorsal slope slightly
curved, sometimes raised almost into an angle behind the
ligament; surface with irregular growth lines; posterior two-
thirds covered with strong, irregular pustules; epidermis red-
dish-brown; pseudocardinals triangular, not greatly rough-
ened ; lateral double in the right valve; beak cavities deep, com-
pressed; muscle scars deep; nacre white or pink, thinner be-
hind where it is often bronzy.

Length 90, height 80, diam. 47 mm.

Length &o, height 84, diam. 43 mm.

Ohio, Cumberland, and Tennessee River systems. Reported
by Keyes at Muscatine, lowa, but this is probably an error.

Type locality, Ohio river.

Unio cooperianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 61, pl.
vill, fig. 21; Obs., I, 1834, p. 173, pl. vit, fig. 21—HANLEY,
Biv. Shells, 1843, p. 180, pl. xxi, fig. 1.—Kuster, Conch.
Cab. Unio, 1861, p. 183, pl. Lv, fig. 5.

Margarita (Unio) cooperianus Lea, Syn., 1836, p. 16; 1838,
ES:

QUADRULA 853

Margaron (Unio) cooperianus Lia, Syn., 1852, p. 22; 1870, p.
34.
Quadrula cooperiana Simpson, Syn., 1900, p. 781.
Plethobasus cooperianus ORTMANN, Ann. Car. Mus., VIII,
1912, p,.. 267.
Unio striatus Reeve, Conch. Icon., XVI, 1864, pl. vii, fig. 30.
Usually somewhat triangular and always having very high
beaks. It is occasionally nearly orbicular in outline. The
epidermis is reddish-brown, the hinder two-thirds of the shell
has very strong, irregular pustules. They are usually strong-
est and longitudinally compressed from the umbonal region
down towards the middle of the base. Very young shells are
greenish-brown or brownish-green.
Ortmann, (1. c.), states that “the anatomy of this species 1s
practically identical with that of P. @sophus, agreeing in all
particulars, chiefly so in the peculiar color of the soft parts.”

QUADRULA MORTONI (Conrad).

Shell subquadrate, inflated, subsolid, sometimes solid when
old, inequilateral; beaks high and full, turned forward over
a lunule; posterior ridge well developed, angled or narrowly
rounded, rarely somewhat double below, ending at the base
of the shell in a blunt point; anterior end rounded, sometimes
slightly, obliquely truncate above; base line straight or lightly
curved; outline of dorsal slope curbed or raised in the middle
to an angle; surface varying from almost smooth to densely
pustulous, pustules generally covering the whole shell; epi-
dermis ashy-brown or lurid brown, having a greenish tint and
sometimes a broad, broken, green ray when young; pseudo-
cardinals triangular, not greatly split up; lateral of the right
valve scarcely double; beak cavities deep, compressed ; muscle
scars impressed ; nacre whitish with a purplish tint, purple and
iridescent behind.

Length 60, height 52, diam. 35 mm.

Lower Mississippi river drainage as far north as western
Tennessee and Indian Territory; west into eastern Texas.

Type locality, Bayou Teche, La.

854 QUADRULA

Unio mortoni Conrap, Monog., II, 1836, p. 11, pl. vr, fig. 1—
Kuster, Conch. Cab. Unio, 1852, p. 51, pl. x1, fig. 1.

Quadrula mortont SIMPSON, Syn., 1900, p. 781.

Unio turgidus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 11, pl. v,
fig. 11; Obs., II, 1838, p. 11, pl. v, fig. 11—Hanuey, Biv.
Shells, 1843, p. 180, pl. xx1, fig. 51.—CHENU, III. Conch.,
1950; Pl. KV, a1oSa ly haope

Margarita (Unio) turgidus Lea, Syn., 1836, p. 16; 1838, p. 15.

Margaron (Unio) turgidus Lea, Syn., 1852, p. 22; 1870, p. 34.
Varies greatly in the degree of smoothness. Some shells

have scarcely a nodule; in others they are crowded over the

whole surface. ‘The pustules are often compressed, sometimes
into short ridges and some of them are laid on obliquely to

the growth lines. .

QUADRULA SPH&RICA (Lea).

Shell subquadrate or suborbicular, inflated, solid, slightly
inequilateral; beaks full and high, turned forward over a
lunule; posterior ridge moderately developed, subangular ; an-
terior end rounded or slightly subtruncate above; base round-
ed: posterior end almost squarely truncated; posterior three-
fifths of the surface somewhat nodulous, the nodules generally
rather feeble; epidermis reddish-chestnut, subshining ; pseudo-
cardinals irregular, somewhat torn and ragged; laterals short,
that of the right valve single or double; beak cavities deep,
compressed; muscle scars deep; nacre brilliant purplish or
violet, richly and darkly iridescent behind.

Length 48, height 48, diam. 35 mm.

Streams of Alabama and Mississippi flowing into the Gulf
of Mexico.

Type locality, Pearl River, Jackson, Miss.

Unio sphericus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145;
jl. Ac. N. Sei. Phila., 1860; p: 310; pl. 11, fe 132;9@bs, Son,
1860, p. 79, pl: El) fig. 132:

Margaron (Unio) sphericus Lea, Syn., 1870, p. 33-

Ouadrula spherica SIMPSON, Syn., 1900, p. 781.

QUADRULA 855

A fine richly-colored species, suborbicular in outline. The
nacre and epidermis are fine, the former having comparatively
few, irregular pustules. It is more inflated, less elongated and
has fainter tubercles than QO. refulgens.

QUADRULA REFULGENS (Lea).

Shell subelliptical, subcompressed to slightly inflated, some-
what inequilateral ; beaks elevated but not inflated, their sculp-
ture a few coarse, nodulous ridges ; posterior ridge subangular,
ending in a blunt point near the base of the shell; anterior
end rounded or very little truncate above; base line curved ;
outline of dorsal slope curved, often raised to an angle in the
middle; on the disk there is a wide band extending from the
umbonal region to the base that is covered with large, low,
rather even nodules; dorsal slope somewhat nodulously wrink-
led; anterior end without nodules ; epidermis reddish-chestnut,
subshining; pseudocardinals triangular, ragged, two in the
left valve and three in the right; lateral in right valve single
or double; beak cavities deep, compressed ; muscle scars small,
impressed; nacre purple or violet, iridescent behind.

Length 48, height 38, diam. 23 mm.

Length 50, height 40, diam. 28 mm.

Mississippi and probably Alabama.

Type locality, Oktibbiha River, Lauderdale Co., Miss.
Unio refulgens Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145;

jim AceN Sci. Phila, Vi, 1860;p.. 317; pl. L1, fig. 130; Obs.,

ME 1860, p: 77, pl. L1, fig. 130.

Margaron (Unio) refulgens Lea, Syn., 1870, p. 34.
Quadrula refulgens StmPson, Syn., 1900, p. 782.
Unio pustulosus Cau, (part), Tr. Ac. Soc. St. Louis, VII,

FSO5, ps 42, pl xv, hese aoe

Typically quite distinct from spherica, but there are exam-
ples that almost connect the two. Generally the pustules on
this species are large, rather regular and evenly spaced, and
they occupy a wide band in front of the posterior ridge, run-
ning vertically, while in spherica they are smaller and less reg-
ularly disposed. The shell is more elliptical and compressed
than spherica.

856 QUADRULA

QUADRULA PUSTULATA (Lea).

Shell subqauadrate, inflated, slightly inequilateral, solid;
beaks high and full, turned forward over a lunule, their sculp-
ture a few coarse, irregular corrugations; posterior ridge well
developed, narrowly rounded or subangular, sometimes in-
clined to be double below; anterior end rounded, sometimes
feebly angled above; base line slightly curved; posterior end
almost squarely truncated, sinused in the middle at the termi-
nation of a radial depression above the posterior ridge; surface
with a few large warts or pustules, often arranged in two im-
perfect rows, one on the posterior ridge, the other some dis-
tance in front of it; epidermis generally smooth, subshining,
ashy-green in young shells, rarely feebly rayed, ashy-brown in
old shells; pseudocardinals considerably split up; lateral of the
right valve single or double; beak cavities deep, compressed ;
anterior scars small, deep; nacre white, iridescent behind.

Length 60, height 53, diam. 33 mm.

Ohio, Cumberland, and Tennessee River systems; Mississip-
pi River and tributaries from eastern Iowa south to Louisiana.
Type locality, Ohio; Tennessee.

Unio pustulatus Lea, Tr. Am. Phil. Soc., IV, 1834, p. 79, pl.
vil, fig. 9; Obs., 1, 1834, p. 89, pl. vi1, ig. 9 —HANtEy,, Biv.
Shells, 1843, p. 178, pl. xxu, fig. 36—CueEnu, Ill. Conch.,
1858, pl. xv, figs. 8, 8a, 8b.

Margarita (Unio) pustulatus Lua, Syn., 1836, p. 15; 1838, p-
se

Margaron (Unio) pustulatus Lea, Syn., 1852, p. 22; 1870, p.
33-

Ouadrula pustulata Stwpson, Syn., 1900, p. 782.

Unio nodulatus Say, Am. Conch., VI, 1834.—Conrap, Monog.,
1837, p. 80, pl. xiv. fig. 1.—Kustrer, Conch. Cab., 1861, p.
264, pl. Lxxxvi, fig. 1—Rerxrve, Conch. Icon., XVI, 1864, pl.
MITT SS

Unio nodulatus RAFinKsouE var. pustulatus Pate, Conch.
Sam., LDL, 18¢0, pp. 16%:

QUADRULA 857

This species is associated with Q. pustulosa and is often
mistaken for it. It has as a rule smoother epidermis, much
fewer and larger tubercles, which are inclined to be placed
in two radial rows. ‘There are occasional specimens, which are
nearly or quite destitute of pustules. Occasionally this species
has a few small nodules on the dorsal slope. ‘The truncation
of the posterior end is strong and, as in some of the species

of this group, the upper part of the truncation often overhangs
the lower part.

QUADRULA NODIFERA (Conrad).

Shell subquadrate or subrhomboid, inflated, moderately solid,
somewhat inequilateral; beaks full and high; anterior end
rounded, usually a little narrowed; base line curved in front,
straight behind; posterior end rounded from the beaks to the
lower end of the posterior ridge; posterior ridge moderately
developed, subangular, ending in front of the extreme poste-
rior end of the shell; surface smooth or having a few scattered
nodules; epidermis dull, dirty or grayish-brown; pseudocar-
dinals triangular, much split up into radial denticles; lateral
of the right valve double or single; beak cavities rather deep ;
muscle scars small, impressed; nacre white or lurid, often
blotched.

Length 47, height 39, diam. 27 mm.

Length 44, height 34, diam. 27 mm.

Louisiana and eastern Texas.

Type locality, Jackson, La.

Unio nodiferus Conran, Pr. Ac. N. Sci. Phila., I, 1841, p. 19;

(i owc Ne Sey Phila. Ie tsco: p.. 277, pl. xxxvii,.fies..4, 8.
Quadrula nodifera Stimpson, Syn., 1900, p. 782.

A somewhat doubtful species. I have seen no specimens,
which exactly agree with the figure of the species as given
by Conrad. Is is usually a little narrowed in front and the
outline of the posterior end sweeps around in an almost regular
curve from the beaks to a point on the base considerably in
front of the extreme hinder part of the shell. It is rarely
raised into a low angle behind the ligament.

858 QUADRULA

There are six shells bearing the name Unio nodiferus Con-
rad in the Philadelphia Academy of Natural Sciences. Part
of them are the same as figured in the Journal, and the rest
are probably mortomi.

QUADRULA CAHABENSIS (Lea).

Shell subquadrate, compressed or subcompressed, slightly
inequilateral, moderately solid; beaks elevated and full; an-
terior end rounded; base nearly straight ; posterior end oblique-
ly truncated, the upper part overhanging ; posterior ridge low,
widely rounded; surface thickly covered, except the upper an-
terior portion, with strong, wart-like tubercles, which on the
posterior slope are sometimes elongated; epidermis tawny to
brownish, showing the dark growth lines; pseudocardinals
radial, roughened; lateral in right valve single or double ; beak
cavities deep, compressed; anterior scars small; nacre flesh-
color or salmon-tinted, brilliant, thinner and iridescent behind.

Length 46, height 37, diam. 18 mm.

Cahawba River, Alabama.

Type locality, Cahawba River, Shelby Co., Ala.

Unio cahabensis Lea, Pr. Ac. N. Sci. Phila., XXIII, 1871, p.
190 3 JL Ac! N Set Fanila., “Viti 1874 ool oleate leemaletes
Ob; SGIIL 1874p: Zu pla ve ere

Quadrula cahabensis SIMPSON, Syn., 1900, p. 782.

I have seen larger shells than the type (whose measure-
ments I have given) in the collection of T. H. Aldrich of Bir-
mingham, Alabama. ‘Typically it is quite distinct from Q.
vallata, being more compressed, more quadrate and having
brighter epidermis and nacre, but I should not be surprised
if an abundance of material would demonstrate that the two
run together.

QUADRULA VALLATA (Lea).

Shell subquadrate, convex or subinflated, solid, subequilat-
eral; beaks neither very full nor high; anterior end slopingly
truncate above, rounded below; base line nearly or quite
~ straight ; posterior end somewhat obliquely truncated, the up-

OQUADRULA 859

per end of the truncation slightly angled; posterior ridge full,

widely rounded; surface more or less covered with low pus-

tules, taking the form on the dorsal slope of nodular, curved
ridges ; epidermis lurid or ashy-brownish; pseudocardinals ra-
dial, rather smooth, two in the left valve and a single or
double one in the right: beak cavities very deep, compressed ;
muscle scars large and deep; nacre dull, lurid whitish.

Length 60, height 53, diam. 30 mm.

Alabama and Black Warrior Rivers, Alabama.

Type locality, Alabama River.

Umio vallatus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 45; Jl-
We: Ns sci Phila., 1860, .p. 315, pl. a, fig: 128; Obs:, XI,
LOGO. P75) Pls L, fig. 128:

Margaron (Unio) vallatus Lea, Syn., 1870, p. 34.

Quadrula vallata SIMPSON, Syn., 1900, p. 782.

Not so quadrate of cahabensis, more inflated, solider and
duller colored throughout. Yet it is quite probable that the
two species run together.

QUADRULA HOUSTONENS!IS (Lea).

Shell subrhomboid or subquadrate, inflated, solid, nearly or
quite equilateral; beaks full and high, turned forward over a
lunule; posterior ridge well developed, narrowly rounded or
subangular, ending at or near the base in a blunt point; an-
terior end rounded, sometimes slightly slopingly truncate
above ; base line curved or nearly straight ; posterior end near-
ly or quite squarely truncated; surface usually free from pus-
tules, rarely having a few feeble ones; epidermis yellowish-
green in young shells, sometimes faintly rayed, becoming ashy
brown or lurid brown when old; pseudocardinals strong, ofte:
split up: left valve with two laterals; right valve with a single
or somewhat double one; beak cavities deep; muscle scars
large, impressed; nacre silvery white.

Length 66, height 59, diam. 38 mm.

Texas and southern Arkansas. Verdigris River, Kansas?

Type locality, Houston and Rutersville, Texas.

860 QUADRULA

Unio houstonensis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p.
£653 jl. Ac: Ny Scie Phifas, LV; 2860; ps 258 ple ne eae
Obs., VIII, p. 40, pl. Lx, fig. 183.—Sowrrsy, Conch. Icon.,
XVI, 1868, pl. LXxxI, fig. 425.

Margaron (Unio) houstonensis Lea, Syn., 1870, p. 55.

Quadrula houstonensis SIMPSON, Syn., 1900, p. 782.

A solid, inflated form with the beaks near the center. Us-
ually the shell is entirely free from tubercles, but occasionally
there are a few weak ones. It is not so smooth as petrina
and the epidermis is duller colored.

QUAPRULA PETRINA (Gould).

Shell subelliptical, subquadrate or subrhomboid, somewhat
inflated, slightly inequilateral, solid; beaks moderately full and
high, turned forward over a lunule, their sculpture consisting
of irregular corrugations, which are almost nodulous on the
posterior ridge; posterior ridge widely rounded, sometimes
feebly biangulate below; anterior end rounded; base line
curved; posterior end obliquely or squarely subtruncate; um-
bonal region corrugated; posterior slope faintly corrugately
wrinkled, the rest of the shell smooth or very feebly corru-
gated; epidermis rather smooth, somewhat shining, sometimes
uniform dirty straw-color, usually yellowish-green with irreg-
ular bands or clouds of green; pseudocardinals stumpy, trian-
gular, two in the left valve and three in the right; beak cavi-
ties deep, compressed; muscle scars deep, smooth; nacre sil-
very, iridescent and thinner behind.

length 70, height 53, diam. 32 min.

Length 47, height 38, diam. 25 mm.

Texas. Cragin’s localities, Verdigris and Neosho Rivers,
Kansas, are probably erroneous. 7

Type locality, Llanos River, Texas.

Unio petrinus Gout, Pr. Bost. Soc. N. Hist., V, 1855, p. 228.
Margaron (Unio) petrinus La, Syn., 1870, p. 55.
Quadrula petrina SIMPSON, Syn., 1900, p. 783.

More inflated, less quadrate or rhomboid than Q. aurea; less
inflated and not so short as Q. houstonensis, and having a dif-
ferently colored epidermis from either.

QUADRULA 861

QUADRULA AURFA (Lea).

Shell subrhomboid, subcompressed to convex, inequilateral,
subsolid; beaks slightly elevated, rather compressed, their
sculpture a few coarse, irregular ridges; posterior ridge round-
ed; anterior end rounded; base straight or lightly curved ; pos-
terior end obliquely, rarely squarely, truncate; surface nearly
smooth; there are occasionally faint plications on the dorsal
slope and a few feeble nodules on the disk; epidermis yellow-
ish-tawny or brownish, rarely greenish or having slight green-
ish markings, scarcely shining; pseudocardinals radial, some-
what split up; lateral of the right valve single or somewhat
double; beak cavities moderately deep, compressed; muscle
scars not deep; nacre whitish, often purple-tinted, iridescent
behind.

Length 62, height 46, diam. 21 mm.

Length 56, height 39. diam. 23 mm.

Length 50, height 34, diam. 22 mm.

Type locality, Texas.

Unio aureus Lea, Pr. Ac. N. Sci. Phila., ITI, 1859, p. 112; Jl.
Ac. N. Sci. Phila., V, 1862, p. 195, pl. xxvi, fig. 264; Obs.,
IX. 1863, p. 17, pl. xxvr, fig. 264—Sowersy, Conch. Icon.,
XVI, 1868, pl. Lxxxm1, fig. 438.

Margaron (Unio) aureus Lea, Syn., 1870, p. 37.

Quadrula aurea StmPsoN, Syn., 1900, p. 783.

Unio bolli Catt, Am. Naturalist, XV, 1881, p. 390.

This species is usually more elongated and more rhomboid
than petrina, less solid and inflated, smoother, and not so
brightly painted. Its beak cavities are generally shallower,
and the beaks are more compressed. Yet there are intermedi-
ates that are hard to place.

QUADRULA ARCHER: Frierson.

“Shell small, thin, lenticular, somewhat quadrate, smooth.
Anterior margin rounded, basal margin slightly curved, dor-
sal margin somewhat bent midway, posterior margin rounded
or bluntly pointed. umbones low and flattened. Sides com-
pressed, raised slightly at the posterior angle, which is nearly

862 QUADRULA

obsolete ; posterior slope wide and somewhat elevated ; epider-
mis smooth, light brown, sometimes inclining to orange, two
or three concentric bands of green or black mark the earlier
lines of growth. ‘Teeth of the left valve double, anterior car-
dinal high, thin and wedge-shaped, the posterior cardinal tri-
angular, low and small; laterals thin, rather short and nearly
straight. In the right valve, the cardinals are divided by a
deep cleft, extending nearly to the bottom of the anterior ad-
ductor scar, the posterior tooth being much the smaller. The
dorsal plate is quite wide for so small a shell. The shell cavity
is quite capacious: the beak cavities deep and compressed.
Nacre white, with brown splotches and very iridescent. The
nacre is probably also salmon-colored in some individuals. The
pallial line in the specimens before me is nearly imperceptibe
in the posterior part of the shell, where the nacre is very thin.
One specimen shows in the upper part of the shell cavity, 20
or 30 almost microscopic muscle scars extending from the beak
cavities half way to the pallial line.

Long. 34, alt. 28, diam. 14 mm.” (Frierson).

‘Type locality, Tallapoosa River, Tallahassee, Ala.

Ouadrula archeri Frierson, Naut., XIX, 1905, p. 13, pl. 1

HES jhe 2:

“This shell is not closely allied to any shell, with which I am
acquainted. On the one hand, it resembles some of the Pleu-
robemas of the group typified by P. fassinans Lea and, on the
other hand, it bears some resemblance to a young and thin Q.
aurea Lea. In the concentric coloring of the lines of growth,
it reminds one of O. asperata Lea. Its deep and compressed
beak cavities place it in the genus Quadrula, while its resem-
blance to the latter two species is too slight to cause any error
in their direction.”

QUADRULA PAUPERCULA (Lea).

Shell subquadrate, a little narrower in front, subinflated,
rather solid, slightly inequilateral; beaks probably full and
high; posterior ridge full, angled, ending at the hinder base
in a blunt point; anterior end round; base curved; posterior
end with a somewhat curved, square truncation ; surface near-

QUADRULA 863

ly smooth; the posterior slope shows faint plications in some
individuals and there are rarely traces of pustules on the disk ;
epidermis greenish-yellow or yellowish-green, somewhat cloth-
like when fresh; pseudocardinals considerably split up; lateral
of the right valve single or partly double; beak cavities moder-
ately deep, compressed; muscle scars small; nacre dirty whit-
ish.

Length 30, height 23, diam. 15 mm.

Lexas:

Type locality, Columbus, Miss.

Unio pauperculus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 39;
ieNce Ne sete hia. Vi 1862, p.90, pl xv, fe. 247; Obs:,
WIE 1662) p. 102, pl. xv, fis. 247.

Margaron (Unio) pauperculus Lea, Syn., 1870, p. 55.

Ouadrula paupercula SIMPSON, Syn., 1900, p. 783.

The above measurements are from the type. I have seen a
specimen in the collection of Wm. A. Marsh, Sr., which is
somewhat larger and has a few faint tubercles on the disk. It
is a doubtful species, and all the material I have seen is prob-
ably young. I,ea’s shell and a couple of others I have seen
have been scraped until the epidermis has been nearly de-
stroyed. The color and the angular posterior ridge differ from
those in any closely allied form, yet it may be the young of
some well-known species.

Group of Quadrula infucata.

Shell small, rounded rhomboid, with a low, distinct posterior
ridge, truncated behind and angled back of the ligament ; beaks
moderately elevated, subcentral; beak sculpture, four or five
coarse, subparallel ridges, which curve upward behind, with
fine, radial ridges between them and the ligament; surface
blackish, sculptured with zigzag or chevron-shaped corruga-
tions, which often become pustulous below; posterior slope
having radial, broken wrinkles ; pseudocardinals small, stumpy ;
secondary lateral of the right valve present ; beak cavities mod-
erately deep, slightly compressed ; anterior scars small, smooth ;
nacre rather dull, purplish.

864 ; QUADRULA

Animal with the marsupium occupying all four leaves of
the gills; inner gills the larger, free from the abdominal sac
only part of their length; anal opening without papille. .

I have been puzzled as to the relationship of this group and
have been strongly inclined to place it near chickasawhensis,
but I now believe it is more closely allied to the pustulosa
group. Its posterior truncation, the prominent angle behind
the ligament, and beak sculpture lead me to place it here. The
general sculpture of QO. petrina approaches that of these species.

QuADRULA INFUCATA (Conrad).

Shell subrhomboid, convex or subinflated, solid, somewhat
inequilateral ; beaks high, rather full, their sculpture consisting
of strong, irregular ridges, which curve up sharply behind,
and behind these there are a few radial, subnodulous ridges;
anterior end a little narrower and rounded; base line curved;
posterior end obliquely subtruncate; posterior ridge full, nar-
rowly rounded, ending in a blunt point on the base line; sur-
face sometimes nearly smooth, but usually sculptured with
low, nodulous ridges arranged in zigzag or chevron-shaped
patterns; epidermis greenish in young shells, thick, black and
subshining in old ones; pseudocardinals considerably split ; two
laterals in the left valve and one, which is often somewhat
double, in the right; beak cavities not very deep, compressed ;
anterior scars small; nacre purplish, iridescent behind.

Length 38, height 30, diam. 17 mm.

Chattahoochee and Flint Rivers, Georgia.

Type locality, Flint River, Ga.

Unio infucatus Conrap, New F. W. Shells, 1834, p. 45, pl.
ut, fig. 2—CuHENU, Bib. Conch., Ist ser., III, 1845, p. 22,
pl. u, fig. 6—Kuster, Conch. Cab. Unio, 1861, p. 176, pl.
Lv, fig. 5.—-Sowxrrpy, Conch. Icon., XVI, 1866, pl. xt, fig.
221.—Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 409, pl.
MNIK, Mes: cae, 10:

Margarita (Unio) infucatus Lea, Syn., 1836, p. 34; 1838, p. 23.

Margaron (Unio) infucatus Lea, Syn., 1852, p. 20; 1870, p. 30.

Unio securiformis Conrap, Ann. and Mag., IV, 1849, p. 300;
Pr. Ac. Nat. Sci. Phila., I, 1850, p. 275, pl. xxxvu, fig. 1.
Generally a little smaller, solider and smoother than klein-

iana and having a darker epidermis.

QUADRULA 865

(QUADRULA KLEINIANA (Lea).

Shell subquadrate, convex to subinilated, solid, inequilateral ;
beaks apparently moderately full and high; posterior ridge
full, almost subangulate, ending at the base of the shell in a
blunt point; anterior end round; base line slightly curved or
straight ; posterior end obliquely truncated; surface generally
covered with chevron-shaped, subnodulous ridges; epidermis
brown, scarcely shining; pseudocardinals triangular ; lateral in
the right valve rarely double; beak cavities not very deep,
compressed ; anterior scars small; nacre dull purplish.

Length 50, height 36, diam. 24 mm.

Sonthern Georgia; northern Florida.

Type locality, Suwanee River, Fla.

Umo klemianus Lea, Pr. Am. Phil. Soc., V, 1852, p. 251; Tr.
Ate Epil SOG, ...;) 0o52, ps 205, pl. xvity fig. 18; Obs:, V,
1852, p. 21, pl. xvi, fig. 18—Rerve, Conch. Icon., XVI,
1864, pl. 11, fig. 6.

Margaron (Unio) kleinianus Lea, Syn., 1852, p. 20; 1870, p.
30.

Quadrula kleiniana Simpson, Syn., 1900, p. 784.

Unio sparsus Kuster, Conch. Cab. Unio, 1861, p. 252, pl.
DASNY, fie. 2.

Generally larger, more elongated, more sculptured and light-
er colored than Q. infucata. The pseudocardinals do not seem
to be so irregular or so much split up. But there are interme-
diates that might almost as well be placed in one species as the
other.

Section Fusconara Simpson, 1900.

Fusconaia SIMPSON, Syn., 1900, p. 784.
Fusconaja ORTMANN, Ann. Car. Mus., VIII, 1912, p. 240.
Shell round, rhomboid, triangular, or short elliptical, with a
moderate posterior ridge; beaks high and full, curved inward
and forward, sculptured with a few coarse, parallel ridges,
which curve upward behind ; epidermis dark ; surface not sculp-
tured ; hinge plate of moderate width; pseudocardinals strong ;
nacre white. salmon or purple.

866 QUADRULA

Animal having all four gills occupied throughout as a mar-
supium, filled with pink or purplish ova when gravid; inner
gills much the wider in front, free generally from the abdom-
inal sac; outer gills cut away slopingly in front.

Type, Unto trigonus Lea.

Ortmann, (1. c.), raises this group to generic rank.

Group of Quadrula beadleiana.

Shell moderately solid, somewhat triangularly rounded,
bluntly pointed and sometimes slightly triangular at post-base,
with a more or less developed posterior ridge, in front of which
it is full; beaks not very high; beak sculpture very coarse, con-
centric ridges; disks irregularly, concentrically striate ; epider-
mis rich, dark chestnut; hinge plate rather narrow; pseudo-
cardinals radial, stumpy: cavity of the beaks only moderately
deep.

No gravid specimens have been seen, but those examined
do not seem to differ from others of the genus.

QuADRULA CHICKASAWHENSIS (Lea).

Shell subelliptical to subrhomboid, compressed to subinflated,
inequilateral, subsclid; beaks only moderately full or high;
posterior ridge full, narrowly rounded or subangular, ending
near the base in a blunt point: anterior end rounded; base
curved; outline of dorsal slope curved, rarely subtruncate;
surface with fine growth lines; epidermis dark brown, some-
times tinted with green, often showing dark rest marks; pseu-
docardinals triangular; laterals curved, sometimes partly dou-
ble in the right valve ; beak cavities only moderately deep; mus-
cle scars impressed ; nacre whitish, pink or salmon-tinted.

Length 55, height 41, diam. 25 mm.

Mississipp1 and Louisiana.

Type locality, Chickasawha River, Miss.

Umno chickasawhensts Lea, Pr. Ac. N. Sci. Phila., V, 1861, p.
3907 Jl) Ae ONe Sc. Phila.= V5 1862, ps. 1Ol plain, ne eenore
Obs WiRE 1862) p. TOs, plans noe sO:

Margaron (Unio) chickasawhensis Lea, Syn., 1870, p. 55.

OQuadrula chickasawhensis SIMPSON, Syn., T1900, p. 785.

QUADRULA 867

The base and dorsal outlines are usually so curved that the
shell is almost evenly short elliptical. It is less inflated, less
solid and more evenly elliptical than Q. beadleiana.

QUADRULA SUCCISSA (Lea).

Shell subrhomboid, convex or subinflated, somewhat inequi-
lateral, subsolid or solid; beaks apparently only moderately full
and high; anterior end, obliquely truncate above, rounded be-
low; base line straight or nearly so; outline of posterior end
curved from the beaks to the base; posterior ridge well devel-
oped, subangular above, inclined to be double below ; surface
finely and unevenly, concentrically striate; epidermis reddish-
brown, sometimes showing faint, dark rest marks, scarcely
shining; pseudocardinals triangular, split up or striated; lat-
erals curved, scarcely double in the right valve; beak cavities
rather deep, compressed; muscle scars impressed; nacre pur-
plish or violet.

Length 44, height 31, diam. 18 mm.

Type locality, West Florida. Also, southern Alabama.
Unio succissus Lea, Tr. Am. Phil. Soc.; X, ‘1852, p. 275; pl.

xxJ, fig. 32; Obs., V, 1852, p. 31, pl. xx1, fig. 32—SOweErRBy,

Conch. Icon., XVI, 1866, pl. xxx, fig. 174.—SIMPSON,

Pie ley SoiNateiMitis., SVs 1802, p. 209, pl. Lxxi,; fig. 5.
Maregaron (Unio) succissus L&A, Syn., 1852, p. 24; 1870, p. 38.
Ouadruia succissa SIMPSON, Syn., 1900, p. 785.

Unie cacao Wes, Pr Ac. N. Sct. Phila., TIT, 1850; p. 154.5 Jil.
AG Ne sci euild., 1V, 1860, p. 344, pl. ivi, fig. 160: :Obs.,
WILE 18005 9: 26; pl. Evi, figs 160.

Margaron (Unio) cacao Lea, Syn., 1870, p. 54.

The type of this is from West Florida and is a subsolid,
scarcely inflated, reddish-brown shell with a purple nacre. It
is an older shell than Lea’s cacao, but I believe that the two
are absolutely identical. In Lea’s collection there is a shell
which he calls Unio succissus, from New Orleans, that I be-
lieve is chickasawhensis and another bearing that name from
Alexandria, Louisiana, is, I think, Quadrula cerina Conrad.

868 QUADRULA

QUADRULA WRIGHTII Nn. s.

Shell subrhomboid or subtriangular, convex to inflated, solid,
inequilateral: beaks somewhat elevated, not inflated, their
sculpture a few coarse, undulating ridges; posterior ridge full,
narrowly rounded, ending near the base in a blunt point; an-
terior end obliquely truncated above, rounded below; base
line curved ; post-dorsal outline usually rounded from the beaks
to the base, sometimes truncated behind; surface irregularly,
concentrically sculptured ; epidermis dark reddish-brown, some-
what silky; pseudocardinals considerably split up; lateral in
right valve sometimes slightly double; beak cavities rather
deep, compressed ; muscle scars small; nacre violet at the bor-
der, lighter colored in the cavity of the shell.

Length 55, height 44, diam. 25 mm.

Length 43, height 37, diam. 25 mm.

Type locality, Pine Barren Creek, Escambia County, Florida.

1 formerly thought this was identical with Q. succissa, but
although the specimens before me show much variation they
differ from that species constantly in being solider, shorter and
in the pattern of coloring of the nacre. Young shells are
shorter and solider than Lea’s cacao.

QUADRULA PUMILA (Lea).

Shell small, subrhomboid, convex, scarcely subsolid, inequi-
lateral; posterior ridge full, somewhat double below ; anterior
end rounded, narrowed and slightly truncate above; base line
nearly straight; posterior end obliquely subtruncated ; epider-
mis reddish-brown, somewhat cloth-like; pseudocardinals tri-
angular ; laterals straight ; beak cavities moderately deep ; mus-
cle scars small; nacre dirty or lurid purplish.

Length 28, height 19, diam. 13 mm.

Type locality, Black river, North Carolina.

Unio pumilus Lua, Tr. Am. Phil. Soc., VI, 1838, p. 23, pl. vir,
fig. 17; Obs., II, 1838, p. 23, pl. vu, fig. 17—HAn ey, Biv.
Shells, 1843, p. 185, pl. xxutr, fig. 13—-CueEnu, Ill. Conch.,
i858, pl. xrx, figs. 1, ra, 1b—Sowersy, Conch. Icon., XVI,
1866, pl. xxxv1, fig. 198.

OUADRULA 869

Margarita (Unio) pumilus Lea, Syn., 1836, p. 20; 1838, p. 17.
Margaron (Unio) pumilus Lea, Syn., 1852, p. 243; 1870, p. 37.
Quadrula pumila SIMPSON, Syn., 1GOO, p. 785.

The type, the only shell I have seen, is a small specimen, so
badly eroded that nothing whatever of the beak characters can
be made out. I cannot be sure where it should go, but am in-
clined to place it in this group.

QUADRULA BEADLEIANA (Lea).

Shell subrhomboid or subtriangular, inflated, solid; beaks
full and high, placed almost centrally ; posterior ridge well de-
veloped, subangular; anterior end rounded, sometimes slightly
truncate above; base line well curved; posterior end obliquely
subtruncated; surface with strong, irregular, concentric
growth lines; epidermis rich reddish-brown, scarcely shining ;
pseudocardinals triangular; laterals curved, that of the right
valve partly double; muscle scars deep; beak cavities not very
deep ; nacre whitish, purple-tinted or salmon.

Length 54, height 45, diam. 34 mm.

Mississippi to eastern Texas.

Type locality, Pearl River, Jackson, Miss.

Unio beadleianus Lua, Pr. Ac, N. Sci. Phila., V, 1861, p. 39;
Jl. Ac. N. Sek Phila., V, 1862, p. 94, pl. xiv, fig. 242; Obs.,
VIII, 1862, pl. 98, pl. xiv, fig. 242.

Margaron (Unio) beadleianus Lea, Syn., 1870, p. 55.

Ouadrula beadleiana Simpson, Syn., 1900, p. 786.

Elliptio beadleianus ORtMANN, Ann. Car. Mus., VIII, 1912,
p. 268.

Much more solid and inflated than chickasawhensis and
rather more truncate behind.

Ortmann, (1. c.), states that only the outer gills are mar-
supial.

QuUADRULA ASKEW! (Marsh).

Shell somewhat rhomboid, inflated, almost or quite equilat-
eral, rather solid; beaks full and high; posterior ridge full,
generally angled above, sometimes biangulate below; anterior
end rounded, obliquely truncate above; base line generally a

870 QUADRULA

little sinuate in front of the posterior ridge; outline of dorsal
slope generally curved, sometimes raised into an angle behind
the ligament; surface somewhat concentrically sculptured ; epi-
dermis dark reddish-brown, dull; pseudocardinals triangular,
ragged; laterals curved; beak cavities moderately deep; mus-
cle scars small; nacre whitish or pinkish.

Length 54, height 40, diam. 29 mm.

Length 70, height 47, diam. 32 mm.

Length 47, height 41, diam. 34 mm.

Western Louisiana; eastern Texas.

Type locality, Village Creek, Hardin Co., and Sabine River,
Nexas.
Unio askewi Marsu, Nautilus, X, 1896, p. 91; X, 1897, pl. 1,

figs.n2, 4.
OQuadrula askew SIMPSON, Syn., 1900, p. 786.

Exceedingly variable. It has a higher, sharper posterior
ridge than beadleiana and is generally more distinctly rhom-
boid.

QuaADRULA LANANENSIS Frierson.

“Shell quadrate to triangular, nearly equilateral, anterior
margin rounded. Base round in front, nearly straight behind.
Posterior oblique, biangular, slightly emarginate. Dorsum
curved; smooth, nearly polished above, striate below and up-
on posterior slope. Lines of growth distinct and ill-defined.
Dark reddish-brown, sometimes a little olive, obscurely radiate.
Beaks eroded. umbos low, somewhat inflated. Anterior um-
bonal slope rounded. Jateral slope flattened. Posterior ridge
angular near the beaks, becoming obsolete near the base. Lig-
ament brown, smooth, medium sized. Shell of medium thick-
ness, thinner behind. Teeth double in left valve, single in
right. Laterals rather thin, nearly straight. Cardinals stumpy.
Muscle scars well marked, generally separate, sometimes con-
fluent. Pallial line distinct in front, less so behind. Cavity of
shell dish-like; of the beaks deep and full. Sometimes the
dorsal muscle scars are situated in the extreme end of the beak
cavity, but generally upon the base of cardinal and dorsal

QUADRULA 875

plate. Nacre rose-color, with blotches of yellow surrounded
by brown. Cavity nearly always studded with numerous pearly
excrescences.

Flesh of the animal whitish or salmon-colored exteriorly,
but shows scarlet when cut. Eggs carried in all four gills,
very red, and the gravid animal thus presents a striking ap-
pearance.

Length 3.2, height 2.3, diam. 1.5 inches.” (Frierson).

Type locality, Lanana Creek, also Banita Creek, near Na-
cogdoches, Texas.

Quadrula lananensis FRIERSON, Naut., XV, 1901, p. 75, pl. Iv.
Fusconaja lananensis ORTMANN, Ann. Car. Mus., VIII, 1912,

Pp. 244.

“Q. lananensis is closely allied to Q. askewi Marsh, both by
its conchological and anatomical characteristics. It may be
differentiated from that shell by being longer, more compress-
ed, more oblique, and its shell is never so inflated and thick-
ened in front as askew? and not so acutely angled on the pos-
terior ridge. Internally, Jananensis is rose-colored nearly in-
variably and the color is uniformly spread over its surface.
Askew is mostly white, and, when colored (pink) the color
is almost always confined exterior to the pallial line. Finally,
Q. askewi never possess those peculiar pearly excrescences,
which seem to belong to lananensis.”

Group of Quadrula undata.

Shell triangular, generally inflated, with high, full beaks,
which are incurved and turned forward over a well-developed
lunule; anterior end obliquely truncate above, often with a
curved, shallow depression in each valve, running from the
beaks to midway down the anterior end, and forming a sort
of secondary Junule ; posterior base, usually incurved ; the pos-
terior ridge ending in a rather sharp point; beak sculpture, a
few coarse, concentric ridges turned upward behind, and often
swollen on the posterior ridge, sometimes becoming finer and
broken or irregular on the upper disk; hinge solid but not very
wide; psetidocardinals triangular and radial, torn; there is a

872 QUADRULA

secondary lateral in the right valve; cavity of the beaks gen-

erally deep and compressed ; muscle scars small, deep.

Animal with the marsupium occupying the whole of all four
branchiz, inner gills generally free from the abdominal sac,
much wider than the outer in front; outer nearly or quite
equaling them in width behind; anal opening distinctly crenu-
late or papillose.

QUADRULA RUBIGINOSA (Lea).

Shell rhomboid, compressed to slightly inflated, swbsolid to
solid, equilateral or inequilateral; beaks high, generally full,
turned forward over a Junule, their sculpture a few corruga-
tions that curve up strongly behind; anterior end rounded, of-
ten slopingly truncate above; base line sometimes slightly
curved, usually straight or feebly sinused in front of the pos-
terior ridge; dorsal slope angled in the middle, obliquely trun-
cate below; posterior ridge high, subangular or narrowly
rounded, ending in a point at the base of the shell; surface
with more or less irregular, concentric sculpture; epidermis
brown or greenish-brown, sometimes feebly rayed, cloth-like
when fresh; pseudocardinals triangular, more or less ragged ;
lateral in the right valve single or double; beak cavities rather
deep; muscle scars impressed; nacre bluish-white to salmon-
tinted, thinner and iridescent behind.

Length 110, height 80, diam. 45 mm.

Length 71, height 52, diam. 29 mm.

Length 68, height 51, diam. 23 mm.

Length 8o, height 68, diam. 42 mm.

Entire Mississippi drainage; eastern Texas; St. Lawrence
River system; Nelson River and its tributaries.

Type locality, Ohio.

Unio rubiginosus Lea, Tr. Am. Phil. Soc., III, 1829, p. 427,
pl. vir, fig. 10; Obs., I, 1834, p. 41, pl. vim, fig. 10.—HAaAnN-
LEY, Biv. Shells, 1843, p. 185, pl. xx1, fig. 43.—CHENU, IIl.
Conch., 1858, pl. xt, figs. 4, 4a, 4b.—REEvE, Conch. Icon.,
XVI, 1865, pl. xxvu, fig. 136—Watton, Moll. Monroe Co.,
1892, p. 16, pl. vit, fig. I.

QUADRULA 873

Margarita (Unio) rubiginosus Lia, Syn., 1836, p. 20; 1838,
pot:

Margaron (Unio) rubiginosus Lia, Syn., 1852, p. 24; 1870,
P- 37:

Unio rubiginosa Dresuayes, An. sans Vert., 3d ed., II, 1839,
pr 672.

Quadrula rubiginosa BAKER, Moll. Chicaco, Pt. 1, 1898, p. 77,
pl. x1x, fig. 2; xx, fig. 1-——Simpson, Syn., Igoo, p. 786.

Fusconaja rubiginosa ORTMANN, Ann. Car. Mus., VIII, 1912,
Dp. 241, figs. 4-4a.

Unio flavus Conran, Monog., IX, 1837, p. 74, pl. xi, fig. 2.—
Koster. Conch. Cab), 1852, p. 61, pl. xiv, fig. 25 p: 265, pl.
EGR Ms fe. 15.

Unio flavus var. rubiginosus Pater, Conch. Sam., IIT, 1890,
p- 152.

Unio trigonus Sowerby, Conch. Icon., XVI, 1868, pl. LXIv, p.
322. ;

This is a very abundant, widespread and variable species.
Some specimens are compressed and long rhomboid, of rather
light structure. Others are subtriangular, inflated, solid and
approach so close to undata that it is a question to which spe-
cies they should be assigned. It is also close to cerina, so much
so that Dr. Lea believed the latter to be synonymous. It is
less strongly sculptured than rubida and does not have the pe-
culiar reddish tint commonly found in that species. It is more
rude than cerina, it is not so richly or darkly colored and it
lacks the rest marks often found in that species.

QUADRULA CERINA (Conrad).

Shell. rhomboid, convex to subinflated, subsolid, inequilat-
eral; beaks somewhat full and high; posterior ridge well de-
veloped, subangular, often slightly double below, ending in a
feeble biangulation at the base of the shell; anterior end
rounded; base line straight or lightly curved; outline of dor-
sal slope raised to an angle in the middle, obliquely truncate
below; surface with faint, uneven, concentric sculpture; epi-
dermis brownish to reddish-brown, generally showing feeble

874 QUADRULA

rest marks, rather cloth-like when fresh; pseudocardinals tri-
angular, rough; laterals curved, that of the right valve usually
single; muscle scars impressed ; beak cavities moderately deep ;
nacre whitish, pinkish, purplish or red.

Length 78, height 56, diam. 32 mm.

Louisiana; eastern Texas; Mississippi; Alabama; north to
Arkansas. .

Type locality, New Orleans, La.

Unio cerinus CONRAD, Monog., XI, 1838, p. 95, pl. L11.—Sow-

ERBy, Conch. Icon., XVI, 1868, pl. Lxxxvi, fig. 468.
Ouadrula cerina Simpson, Syn., 1900, p. 787.

Fusconaja cerina OrRTMANN, Ann. Car. Mus., VIII, 1912, p.

243.

I have before me a shell from Lanana Creek, Nacogdoches
County, Texas, which agrees well with Conrad’s figure of
Unio cerinus. Other shells before me probably belong to the
same species, but are not so typical. The waxen spots on the
nacre, for which he bestowed the name cerinus, are present in
the specimen before me from Texas and are probably patho-
logic. In this shell they are bronzy-yellowish.

QUADRULA HEBETATA (Conrad).

Shell quadrate, rather inflated, solid, slightly inequilateral ;
beaks moderately full and high; posterior ridge full, curved,
angled throughout its length, ending in a point at the base of
the shell; anterior end rounded; base line nearly or quite
straight ; posterior end truncated, the upper part overhanging,
the truncation slightly curved; surface rough, somewhat con-
centrically sculptured; epidermis dull, shaggy, ashy-brown or
blackish; pseudocardinals triangular, somewhat ragged; lat-
eral in right valve somewhat double; muscle scars deep; beak
cavities deep and compressed ; nacre white.

Length 67, height 54, diam. 35 mm.

Type locality, Missouri. Also, Tallapoosa River, Alabama.
Unio hebetatus Conran, Jl. Ac. N. Sci. Phila., II, 1854, p. 2096,

pl. xxv1, fig. 5.

Margaron (Unio) habetatus Lea, Syn., 1870, p. 38.
Ouadrula hebetata Simpson, Syn., 1900, p. 787.

QUADRULA 875

A peculiarly quadrate form, the posterior end being trun-
cated and slightly rounded, the upper portion overhanging.
The posterior ridge is curved and sharp throughout and the
surface is rough. It seems to be rather rare. I have seen spec-
imens larger than the one whose measurements are given
above. It is more quadrate and less inflated than chunit.

QUADRULA RUBIDA (Lea).

Shell long rhomboid, convex to inflated, rather solid, inequi-
lateral ; beaks high, more or less inflated, their sculpture con-
sisting of numerous corrugations that curve up behind; pos-
terior ridge full, sharp above, narrowly biangulate below, end-
ing at the shell’s base in a point or double angle; anterior end
rounded, sometimes obliquely truncate above ; base line straight
or incurved in front of the posterior ridge; outline of dorsal
slope curved or raised to a decided angle behind the ligament ;
surface covered with strong, concentric ridges; epidermis
greenish to reddish-brown, sometimes feebly rayed in the
young shell; pseudecardinals triangular, rough; lateral of right
valve single or partly double; beak cavities moderately deep,
compressed ; muscle scars impressed ; nacre white or flesh-color.

Length 82, height 60, diam. 40 mm.

Length 73, height 55, diam. 34 mm.

Length 70, height 48, diam. 24 mm.

Streams flowing into the Gulf of Mexico from Alabama to
Louisiana.

Type locality, Tombigbee River, Miss.; Coosa River and
Big Prairie Creek, Ala.

Unio rubidus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 40; Jl.
Ace (Nee Sciaohilap se tsG2rn ps OSaspl. \ xiv, fies. 244-5 Obs.,
VIII, 1862, p. 99, pl. xiv, fig. 244.

Margaren (Unio) rubidus LEA, Syn., 1870, p. 35.

Ouadrula rubida SIMPSON, Syn., 1900, p. 787.

Unio negatus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 59; JI.
nee, sci, Phila. VW; 1662. pe Zo, pl. 1x, fig.225; Obs., VILL,
1862, p. 80, pl. 1x, fig. 225.—Sowersy, Conch. Icon., XVI,
1866, pl. Xxx, fig. 165.

Margaron (Unio) negatus Lua, Syn., 1870, p. 35.

876 QUADRULA

I hardly see why Dr. Jlea made two species out of this form
which is reasonably constant in its characters. It is shaped
something like Q. cerina but is strongly, concentrically ridged.
It is more evenly quadrate and more strongly sculptured than
rubiginosa.

The shell reported under the name Unio negatus, from Kan-
sas, is probably a somewhat sulcate rubiginosa.

QUADRULA RUBIDULA Frierson.

“Shell small, heavy, somewhat triangular; base emarginate ;
dorsum arched; posterior angle biangulate ; ligament elevated,
light red. Beaks not very high; umbones inflated; sides flat-
tened; epidermis brown, rough, obsoletely raved and showing
traces of a greenish tint. Cardinals stout, short, rough, in-
clined to be double in both valves; laterals rather short, heavy,
rough and slightly curved; cavity of shell very irregular, ex-
cavated from beak to posterior margin; beak cavity deep and
compressed; nacre white, sometimes pinkish, not very iride-
Scent.

Length 36, height 32, diam. 22 mm.” (Frierson).

Type locality, Mulberry River; Black Warrior River and
North River, Ala.

Ouadrula rubidula Frierson, Naut., XIX, 1905, p. 14, pl. 1,

figs: 324.

“The shell is close to QO. rubida Lea and some forms resem-
ble some of the depauperate specimens of Q. trigona Lea.
From either of these species it may be differentiated by its
small size and by the biangulated posterior angle.”

QuapRULA CHUNITI (Lea).

Shell subtriangular or subrhomboid, rather solid, inflated,
somewhat inequilateral; beaks high and full with strong, ir-
regular corrugations, and a few radial linze behind them; an-
terior end rounded, somewhat obliquely truncate above ; base
straight; dorsal slope with an angle behind the ligament,
obliquely truncate below ; surface feebly, concentrically sculp-
tured; epidermis brownish or greenish-brown, often faintly

QUADRULA 877

rayed, cloth-like; pseudocardinals ragged, the anterior one in

the left valve compressed and joined to the posterior one;

laterals curved, that of the right valve partly double; muscle
scars impressed, the posterior ones round; nacre bluish-white,
thinner behind; beak cavities deep, compressed.

Length 57, height 48, diam. 33 mm.

Mississippi; west to central Texas north to Arkansas.

Type locality, Dallas, Texas.

Unio chunu, Es, Pr. At. N, Sci; Phila.; V, 186%, p. 392; Jl.
Hensel i tila, Vo Ta62..p. 160, pl. XxvIL, p. 265; Obs.,
DXrs69.sp. 18; ple xxvun, fig, 265.

Margaron (Unio) chunu Tea, Syn., 1870, p. 38.

Quadrulo chunu Simpson, Syn., 1900, p. 787.

Close to wndata and certain specimens can scarcely be sepa-
rated from that species. It is generally less triangular, the
beaks are not so full and high, the posterior ridge is not so
pronounced and it has a smoother, less rude shell than that
species.

Var. nasuta n. v.

More elongated, more drawn to a point at the posterior base
than the type, less solid, with a higher posterior ridge.
Length 55, height 39, diam. 30 mm.

I formerly thought this was a variety of cerina but since
seeing what I believe are valid specimens of that I am inclined
to make it a variety of chuni?. ‘Typically it is quite different,
but material before me seems to connect the two.

QUADRULA CASTANEA 0. S.

Shell irregularly ovate, inflated, solid, inequilateral; beaks
full and elevated ; posterior ridge fairly well developed, single
or imperfectly double, narrowly rounded, angular or slightly
biangulate ; anterior end rounded or subtruncate above, some-
times having an angle at the front end of the compressed
lunule; base line lightly curved to straight; outline of dorsal
slope lightly curved from the beaks to near the base, sometimes
raised into a low angle behind the ligament; surface rather

878 QUADRULA

rough, irregularly, concentrically striate; epidermis reddish-
brown, wrinkled, rarely feebly rayed; pseudocardinals ragged,
the anterior of the left valve often compressed and joined to
the posterior one; muscle scars small and deep; beak cavities:
moderately deep, compressed; nacre whitish to salmon, dull,
much thicker in front, sometimes obliquely ribbed.

Length 64, height 44, diam. 27 mm.

Length 50, height 38, diam. 26 mm.

Type locality, Tombigbee River, Moscow, Alabama.

This species has something of the form of a Pleurobema,
but it has a higher and different posterior ridge and the beak
cavities are deeper than in any Pleurobema I know of. There
are four shells before me, which vary considerably, but they
agree in essential characters. They are about as much elongat-
ed as the form I have called chan var. nasuta, but are more
nearly oval. they have no such beak behind, the posterior ridge
is lower and the epidermis has a reddish tint.

QUADRULA RIDDELLIT (Lea).

Shell short, subquadrate, inflated, sclid, equilateral.or nearly
so; beaks high and full, turned forward over a lunule, their
sculpture consisting of numerous corrugated ridges that are
strongly curved up behind; posterior ridge elevated, carinated
throughout, ending in a point near the base of the shell; an-
terior end almost evenly rounded, having a slight oblique trun-
cation above; base line rounded; posterior end almost squarely
truncated, the upper part sometimes overhanging a little, with
an angle behind the ligament; surface unevenly, concentrically
striate; epidermis greenish-brown; pseudocardinals rough,
irregular ; laterals short, that in the right valve somewhat dou-
ble; muscle scars small, deep; beak cavities moderately deep,
compressed ; nacre bluish-white, thinner and iridescent behind.

Jlength 35, height 34, diam. 23 mm.

Length 36, height 34, diam. 20 mm,

astern ‘Texas; western Louisiana ?

Type locality, Dallas, Texas.

QUADRULA 879 ;

Unio riddellii Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 392; Jl.
ac, N; ect. Phila. V,. 1862;p. 198, pl..xxvit, fig. 267: Obs.,
1X, 1863, p. 20, pl. xxvu, fig. 267—Sowrrzy, Conch. Icon.,
XVI, 1868, pl. LXxxi1I, fig. 442.

Margaren (Unio) riddell Lua, Syn., 1870, p. 38.

Quadrula riddellii SIMPSON, Syn., 1900, p. 787.

Pleurobema riddellii ORrTMANN, Ann. Car. Mus., VIII, 1912,
Pp 262.

This seems to be a rare species and I have never séen more
than four or five specimens that I could refer to it with any
certainty. The overhanging of the posterior truncation and
the rounded base will distinguish it from Q. friersoni. It is
more inflated in the middle of the disk than that species or
chunu. Yet some intermediate material that I have seen
hints at a connection with the latter.

QUADRULA._ FRIERSONT (B. H. Wright).

Shell triangular, inflated, solid, nearly or quite equilateral ;
beaks very high and full, their sculpture apparently consisting
of numerous oblique corrugations; posterior ridge high, an-
gled, ending near the base of the shell; anterior end obliquely
subtruncated above. rounded below; base line in adult shells
nearly straight; outline of dorsal slope curved, often elevated
into a low angle behind the ligament; surface irregularly, con-
centrically striate; epidermis varying from ashy-brown to red-
dish-brown; pseudocardinals triangular rough; lateral of
right valve partly double; beak cavities moderately deep, com-
pressed; muscle scars small, impressed; nacre whitish to pur-
ple.

Length 56, height 49, diam. 35 mm.

Length 43, height 37, diam. 27 mm.

Louisiana: eastern Texas.

Type locality, Bayou Pierre, De Sota Parish, La.

Unio friersoni B. H. Wricut, Nautilus, IX, 1896, p. 134, pl.

IIT.

Ouadrula-friersont Stmpson, Syn., 1900, p. 787.

880 QUADRULA

The beak sculpture of this form seems to be different from
that of any allied species. I have never seen it perfect, but
it is apparently oblique or zigzagged. It is longer in propor-
tion to its height than ;iddellii, is more distinctly triangular
than it or chunti.

QuADRULA UNDATA (Barnes).

Shell triangular, inflated, solid, slightly inequilateral ; beaks
very high and full, turned forward over a lunule, their sculp-
ture a few irregular ridges, which turn up behind and occa-
sionally two or three rayed lire behind them; anterior end
usually obliquely truncate above and angular in front of the
lunule, though rarely evenly rounded; base line straight or
lightly sinused in front of the posterior ridge; outline of dor-
sal slope often curved, raised into a low angle behind the
ligament; posterior ridge well developed, angled or narrowly
rounded, ending in a blunt point at the base line; in front of
the posterior ridge there is generally a wide, radial depression
and in front of this is the greatest diameter; surface with
uneven growth lines; epidermis brownish-green and_ faintly
rayed in the young state, greenish-brown, brownish or black-
ish in the old shell, rather dull; pseudocardinals strong, torn;
lateral of the right valve often partly double; muscle scars.
very deep; beak cavities moderately deep ; nacre white, salmon
or rose-tinted, thinner behind.

Length 87, height 70, diam. 52 mm.

Length 85, height 74, diam. 52 mm.

Length 50, height 50, diam. 38 mm.

Entire Mississippi drainage; Coosa River, Alabama; Michi-
gan and the Upper St. Lawrence drainage.

Type locality, Wisconsin and Fox Rivers.

Unio undatus BARNES, Am. Il. Sci., VI, 1823, p. 121, pl. rv, fig.

A.

Mya undata Eaton, Zool. Text book, 1826, p. 219.
Ouadrila undata WaiKER, Naut., XXIV, 1910, p. 24, pl. 1,

figs. 1-3; pl. 11, figs. 1-2.

Fusconaja undata OrtTMANN, Ann. Car. Mus., VIII, 1912, p-

241.

QUADRULA 881

Unio trigonus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 110, pl.
XVI, fig. 40; Obs., I, 1834, p. 120, pl. xvi, fig. 40—HANLEy,
Biv. Shells, 1843, p. 185, pl. xx1, fig. 6.—CueEnu, Ill. Conch.,
1858, pl. xvi, figs. 7, 7a, 7b.—Sowersy, Conch. Icon., XVI,
1868, pl. LXXXVI, fig. 450.

Margarita (Unio) trigonus Lira, Syn., 1836, p. 18; 1838, p. 17.

Margaren (Umo) trigonus Lea, Syn., 1852, p. 25; 1870, p. 38.

Quadrula trigona BaxeEr, Moll. Chicago, Pt. 1, 1808, p. 76, pl.
Xv, fig. 5—S1mpson, Syn., 1900, p. 787.

Unio triangularis KustER, Conch. Cab. Unio, 1852, p. 56, pl.
EEL, LS.

Unio pilaris Reeve, Conch. Icon.; XVI, 1865, pl. xxvu, fig. 138.

Quadrula obliqua (part), Stmpson, Syn., 1900, p. 788.
This abundant species approaches closely to several others

but in all cases that I have seen there is a wide, shallow radial
groove in front of the rather sharp, well-defined posterior
ridge and in front of this depression the disk is swollen, so that
along this swelling the shell has a much greater diameter than
at the posterior ridge. There is usually a large, wide lunule,
and often below this there is an illy-defined, flattened area,
which almost forms a second lunule. In chunii and friersoni
there is no such lunule-like depression and scarcely anything
of the radial depression on the disk. Q. rubiginosa is gener-
ally considerably less inflated than wndata and lacks the second
lunule and radial depression, but there are intermediate shells
that may be referred to one species as well as to the other.

QUADRULA OBLIQUA (Lamarck).

Shell subtriangular, inflated, solid, somewhat inequilateral ;
beaks very high and full, turned inward and forward over a
decided lunule, their sculpture a few, coarse, irregular ridges
that are turned up behind, and nodulous on the posterior ridge;
anterior end usually obliquely truncate above, rounded below;
base line usually lightly sinused in front of the posterior ridge ;
outline or dorsal slope generally almost evenly curved from the
beaks to the base; posterior ridge rather low but well develop-
ed, narrowly rounded, placed near the edge of the shell and
curved throughout ; in front of the middle of the shell is a high.

882 QUADRULA

wide, curved, radial swelling ; between this and the much lower
posterior ridge is a wide, curved, radial depression; surface
having irregular, concentric striz ; epidermis tawny-brown and
raved in the young, dark reddish-brown in the old shells, dull;
pseudocardinals ragged; lateral of right valve partly double;
muscle scars and beak cavities deep; nacre white, thinner and
somewhat iridescent behind.

Length 115, height 95, diam. 57 mm.

Length 95, height 78, diam. 50 mm.

Length 77, height 69, diam. 40 mm.

Ohio, Cumberland, and Tennessee River systems; west in
Illinois to the Mississippi; Claiborne, Alabama.

Type locality, Ohio River.

Unio obliqua I.AMarcK, An. sans Vert., VI, 1819, p. 72.

Margarita (Unie) obliqua Lea, Syn., 1836, p. 20.

Quadrula obliqua Simpson, Syn., 1900, p. 788.

Unio obliquus HANLEY, Biv. Shells, 1843, p. 186, pl. xx, fig.
24.—KusTer, Conch. Cab. Unio, 1852, p. 63, pl. xv, fig. 1.—
CALE, Ir. Xe. Ser St. Louise Ville r8o5 mare te eplcany:

Margarita (Unio) obhiquus Lea, Syn., 1838, p. 17.

Margaron (Unio) obliquus Lea, Syn., 1852, p. 25; 1870, p. 38.

Pleurobema obliquum OrtTMANN, Ann. Car. Mus., VIII, 1912,
Dp: 2045

Unio mytiloides SHort and Eaton, Transylvania Jl., 1831, p.
74-

Unto cerdatus Conrap, Monog., V, 1836, p. 48, pl. xxv.—
Kuster, Conch. Cab., 1852, p. 57, pl. x1, fig. 1.—SoweErsy,
Conch: licon., SOV, 1868; ply L xxii, 376,

The posterior ridge and outline of the dorsal slope are curv-
ed. In wndata the posterior ridge is straight, and the post-dor-
sal outline is raised to an angle in the middle. QO. obliqua ap-
proaches more nearly to an equilateral triangle than either
pyramidata or solida. It is less inflated and longer than
plena.

Ortmann, (1. c.), states that only the outer gills are marsupi-
al, But Lefevre and ‘Curtis, (Bull, Bur Fish, XOGX, 1or2:
p. 120), find that all four gills are used for that purpose.

Ortmann also remarks that this species, in his opinion, is
not specifically different from coccineum.”

QUADRULA 883

QUADRULA COCCINEA (Conrad).

Shell subtriangular, convex to moderately inflated, inequi-
lateral, solid; beaks high, moderately full, turned forward over
a lunule, their sculpture a few corrugations which curve up
behind; anterior end generally obliquely truncated above,
rounded below ; base line straight or curved; outline of dorsal
slope curved, usually subangulate behind the ligament; pos-
terior ridge narrowly rounded above, widely rounded below,
ending near the base in a blunt point or faint biangulation ;
the shell has its greatest diameter in front of the middle but
there is no radial depression behind it; surface with irregular
growth lines ; epidermis brownish or reddish-brown, somewhat
cloth-like when not rubbed; tawny or yellowish-green and
raved when young; pseudocardinals triangular ; lateral of left
valve more or less double; beak cavities moderately deep, com-
pressed; muscle scars impressed; nacre rich pink, salmon-
tinted, flesh-colored or white, thinner and iridescent behind.

Length roo, height 76, diam. 43 mm.

Length 90, height 74, diam. 41 mm.

Entire Upper Mississippi drainage; St. Lawrence basin in
various localities. |

Type locality, Mahoning River, near Pittsburgh.

Unio coccinetis CONRAD, Monog., III, 1836, p. 29, pl. x11, fig.
fee br. im hike sec. Villn83s,-p: 12, pl..v, fis.12;
Obs., II, 1838. p. 12, pl. v, fig. 12—HANLEy, Biv. Shells,
1843, p. 203, pl. xx, fig. 54——Kustrer, Conch. Cab., 1852,
p. 49, pl. x, fig. 2.—CuHeENv, II]. Conch., 1858, pl. xxv, figs.
4, ta, 4b.—Sowerry, Conch. Icon., XVI, 1868, pl. xcrv, fig.
Hie.

Margarita (Unio) coccineus LEA, Syn., 1836, p. 34; 1838, p. 23.

Margaron (Unio) coccineus Lea, Syn., 1852, p. 35; 1870, p. 56.

Ouadrula coccinea BAKER, Moll. Chicago, Pt. 1, 1898, p. 79, pl.
XIV, fig. 1; pl. xrx, fig. 3—S1mpson, Syn., 1900, p. 788.

Pleurobema coccineum OrRtMANN, Ann. Car. Mus., VIII,
Ione p. 263:

Unio rubens Menke, Syn., Meth. Moll., 1828, p. go.

$84 QUADRULA

Unio catillus Conrap, Monog., III, 1836, p. 30, pl. xm, fig. 2.

—Kusterr, Conch. Cab., 1852, p. 64, pl. xv, fig.-2.

Unio catilis B. H. Wrtcut, Check List, 1888.
Unio gouldianus Warp, Jay’s Catalogue, 3d ed., 1839, p. 24.
Unio cuneus. Cat, Tr. Ac. Sci. St. Louis, VII, p. 14.

In the Transactions of the American Philosophical Society,
VI, 1838, p. 12, pl. v, fig. 12, Lea described this species, and
stated that about eighteen months previous Dr. Hildreth had
sent him a single specimen under the name Unio coccmeus;
but there is nothing to show that Hildreth had described it.
In the Monography in 1836, III, p. 20, pl. xin, fig. 1, Conrad
describes this species under the same name, and also credits it
to Hildreth, stating that it was in the collection of the Phila-
delphia Academy of Natural Sciences under that name. ‘The
species must be credited to Conrad, who first described it,
though I,ea read his description in 1834.

This is an exceedingly variable species and difficult to
diagnose. It is more compressed than solida, the beaks are not
quite so high, there 1s no such full, median, radial swelling,
and it does not have a radial depression in front of the poste-
rior ridge. Yet there are intermediates that I do not believe
any one can satisfactorily name. ‘This species occasionally
shows dark rest marks.

Ortmann, (1. c.), states that in this species only thé outer
gills are marsupial.

Var. magnalacustris n. n.

Shell much smaller than the typical form, subinflated to
inflated, subsolid; epidermis light reddish-brown, with darker,
impressed rest marks, subshining.

Length 49, height 39, diam. 23 mm.

Length 44, height 30, diam. 24 mm.

Type locality, St. Lawrence basin at and near Niagara Falls.
Quadrula coccinea var. paupercula SIMPSON, Syn., 1900, p.

789.

In this form the epidermis is almost shining, a light reddish-
brown and the darker rest marks are decidedly impressed.

QUADRULA 885

Some of the specimens are distorted and have the upper part
of the anterior end decidedly angled. But all are of light, deli-
cate structure. The name paupercula having already been
used by Lea for a species of Quadrula, | am obliged to change
the name of this form.

QUADRULA SOLIDA (Lea).

Shell having almost the form of a right-angled triangle, gen-
erally inflated, solid, inequilateral ; beaks high and full, turned
forward over a wide lunule, their sculpture a few strong, irreg-
ular ridges that curve up behind; anterior end squarely or
somewhat obliquely truncated above, rounded below ; base line
nearly or quite straight ; outline of dorsal slope lightly curved ;
posterior ridge not greatly elevated, rounded, ending in a
rounded point at the base of the shell; there is a wide inflation
running from the beaks down to a little in front of the middle
base; between this and the posterior ridge there is scarcely
any depression ; surface with irregular growth lines ; epidermis
greenish-brown to reddish-brown, somewhat silky when fresh,
slightly rayed in young shells ; pseudocardinals strong, ragged ;
lateral of the right valve usually somewhat double; muscle
scars deep ; beak cavities moderately deep; nacre white, yellow-
ish, salmon-tinted or pink.

Length 115, height 75, diam. 43 mm.

Length 110, height 67, diam. 44 mm.

Length 70, height 68, diam. 41 mm.

Length 72, height 65, diam. 42 mm.

Ohio, Cumberland, and Tennessee River systems; south to
Louisiana; west to Arkansas and Kansas; north to Minnesota ;
east, through Wisconsin, Illinois, and Indiana, to Ohio.

Type locality, Ohio River, Cincinnati; Mahoning River,
Ohio.

Unio solidus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 13, pl. v, fig.
13; Obs., II, 1838, p. 13, pl. v, fig. 13—HANLEy, Biv. Shells,
1843, p. 186, pl. xxi, fig. 15 —CHENU, Ill. Conch., 1858, pl.
XXV, figs. 2, 2a, 2b.—-Kuster, Conch. Cab., 1861, p. 258, pl.
LXXXvil, fig. 4.—RreEve, Conch. Icon., XVI, 1865, pl. xxvIt,
fig..1 33.

886 QUADRULA

Margarita (Unio) solidus Lea, Syn., 1836, p. 20; 1838, p. 17.
Margaron (Umo) solidus lea, Syn., 1852, p. 25; 1870, p. 38.
Quadrula solida StMpPson, Syn., 1g00, p. 789.

?Unio cardiacea DesHAyes, Tr. Elem. de Conch., 1839, p. 19,
pla xx xt ess te2: :
Unio fulgidus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164; Tr.

Am. Phil. Soc, X, 1848, px 735pl: iv, fis-.105 Obs:, WWE 348

p47, play, fig 10:

Margaron (Unio) fulgidus Lea, Syn., 1852, p. 25; 1870, p. 38-
Unio obovalis Conran, Pr. Ac. N. Sci. Phila., VI, 1853; p. 253.

It is almost impossible to draw up a description that will
characterize all the variations of this protean species and sepa-
rate it from the other closely allied forms. Generally its out-
line approaches that of a right-angled triangle, the beaks being
full, high and piaced far forward. ‘The anterior end is ordi-
narily truncated, sometimes squarely, occasionally falling back
a little above. The base line is nearly straight; the post-dorsal
outline is lightly curved; the posterior ridge is low and nearly
straight. Although the shell has its greatest diameter in front
of the middle there is scarcely any depression between this
inflation and the posterior ridge as there is in plena, undata,
obliqua and many specimens of pyramidata.

I have seen numerous old shells, which are much lengthened
at the posterior base, with high beaks placed far forward that
I have been unable to satisfactorily name. One of these is in
the Lea collection and Dr. Lea calls it Unio solidus. 1 cannot
be sure whether he is right or wrong.

QUADRULA PLUNA (Lea).

Shell short and high, subtriangular, inflated, inequilateral,
solid; beaks very full and high, turned forward over a deep,
ragged lunule, sculptured with a few irregular nodulous ridges ;
anterior end strongly and obliquely truncated, the truncation
often developed into a second lunule; base line short, straight
or lightly sinused in front of the posterior ridge; outline of
dorsal slope curved; posterior ridge narrowly rounded, curved,
ending at the base in a blunt point; median radial ridge full

QUADRULA 887

and wide; between it and the posterior ridge there is generally
a radial depression; surface with irregular growth lines; epi-
dermis cloth-like, reddish-brown, dull and rather rough; pseu-
docardinals radial, somewhat split up; lateral of the right valve
more or less double; beak cavities deep, compressed; muscle
scars small, deep; nacre white, thinner and iridescent at the
posterior base.

Length 54, height 6o, diam. 38 mm.

Length 50, height 53, diam. 33 mm.

Ohio, Cumberland, and Tennessee River systems ; southwest
to Kansas and Arkansas.

Type locality, Ohio River, Cincinnati, Ohio.

Unio plenus Ura, Pr. Am. Phil. Soc. 1, 1840, p. 286; Tr. Am.
Pink Socy VEIT, 1843, p21, pl. xy Ge: 26; Obs., I, 1842.
p- 49, pl. xtv, fig. 26.—Kusrer, Conch. Cab., 1861, p. 264, pl.
LXXXJX, fig. 3—Sowersy, Conch. Icon., XVI, 1868, pl.
ET ho. 205.

Margaron (Unio) plenus Les, Syn., 1852, p. 25; 1870, p. 39-

Quadrula plena Stupson, Syn., 1900, p. 790.

Close to several species, yet probably as distinct as any
member of the group. It is usually a little higher than wide
and in this character it differs from obliqua and solida. ‘The
epidermis is rougher and more cloth-like than in any allied
species. The post-basal point is short and never drawn out as
it is in solida or pyranudata.

QUADRULA FLEXUOSA Simpson.

Shell subtriangular, solid, inflated with a feebly double pos-
terior ridge, which ends in a blunt point or slight biangulation
at the base of the shell, inequilateral; beaks high and rather
full, badly eroded in the only shell seen; anterior end rounded ;
base line nearly straight, slightly sinused at the lower end of
a wide, radiating depression in front of the posterior ridge;
outline of dorsal slope almost evenly curved; epidermis rough-
ly, concentrically striate, tawny to brownish, showing the rest
marks ; hinge plate wide and flat ; pseudocardinals low, diverg-
ing, ragged; laterals straight, short, that of the right valve

888 QUADRULA

double; anterior muscle scars deep; posterior scars distinct;
nacre lurid whitish, dull.

Length 65, height 55, diam. 33 mm.

Type locality, Holston River, Tennessee.

Quadrula flexuosa Stmpson, Proc. Ac. N. Sci. Phila., 1900, p.

83, pl. m1, fig. 8; Syn., 1900, p. 790.

The above form shows relationship to several others, yet
although I have only seen a single shell, which is in the col-
lection of Mr. L. S. Frierson, I cannot connect it with any-
thing else. It is less inflated and more elongated than Q. plena,
it is less triangular than Q. obliqua and the light-colored epi-
dermis with the distinct rest marks differs from that of any
related species:

QuADRULA PYRAMIDATA (Lea).

Shell generally, when adult, having the outline of a scalene
or right-angled triangle, the beaks being placed at the extreme
anterior point and often projecting in advance of the rest of
the shell, subinflated or inflated, solid; beaks high and full,
turned forward over a wide, deep lunule that passes forward
under them; anterior end truncated squarely or with a slope
below and usually having a large, faint second lunule; base
line nearly or quite straight; outline of dorsal slope lightly
curved; posterior ridge, low, rounded, ending in a rounded
point at the base of the shell; median ridge very high, rounded,
curved, usually separated from the posterior ridge by a radial,
concave depression; surface with irregular growth lines; epi-
dermis brown to blackish, brownish-green and rayed in young
shells, scarcely subshining; pseudocardinals radial, often ob-
lique, torn; lateral of right valve more or less double; muscle
scars small, deep; beak cavities deep, compressed ; nacre rose-
colored or white, rarely yellowish or salmon, thinner and
iridescent behind.

Length along base 75, from beaks to post-base 84, height 63,
diam. 41 mm.

Length over all 110; height 60, diam. 47 mm.

Length on base 105, over all 115, height go, diam. 58 mm.

QUADRULA 889

Ohio, Cumberland, and Tennessee River systems ; southwest
to Arkansas; west to Nebraska’; north in the Mississippi to
Prairie du Chien, Wisconsin.

Type locality, Ohio.

Unio pyramidatus Lea, Tr. Am. Phil. Soc., [V, 1834, p. 109,
pl. xvi, fig. 39; Obs., I, 1834, p. 119, pl. xvi, fig. 39.—Han-
LEY, Biv. Shells, 1843, p. 186, pl. xx, fig. 45—DESHAYES,
Traite Elem..de Conch., II, 1850?, p. 216, pl. xxxz1, figs. 1, 2.
—CHENJ, III. Conch.» 1858, pl. xvi, figs. 5, 5a, 5 —SowEr-
By, Conch. Icon., XVI, 1868, pl. Lxrv, fig. 323.

Margarita (Unio) pyramidatus Lea, Syn., 1836, p. 21 ; 1838, p.
17.

Margaron (Unio) pyramidatus Lea, Syn., 1852, p. 25; 1870, p.
39.

Quadrula pyramidata SIMPSON, Syn., 1900, p. 790.

Pleurobema pyranidatum OrtMANN, Ann. Car. Mus., VIII,
1912, p. 264.

Umio mytiloides Desuayes, Enc. Meth., II, 1830, p. 586, pl.
CCXLIX, fig. 4—ConraAp, Monog., IV, 1836, p. 41, pl. xx.—
Swainson, Treatise on Mal., 1840, p. 267, figs. 52-53.—
Muster= Conch. Cab 1852, p> 50; pl. xu, ‘fig. 3; 1861, p:
265, pl. LXXXIXx, fig. 4.

Margarita (Unio) mytiloides Lea, Syn., 1836, p. 21; 1838, p.
17.

Margaron (Unio) mytiloides Lea, Syn., 1852,, p. 25; 1870, p.
39. ‘

Unio mytiloides Rafinesque var. pyramidatus Pavre., Conch.
Sam., IIT, 1890, p. 160.

Unio cardiacea GUERIN, Icon. Regne Animal, 1828?, IT, pl.
SRV, ees 7.

Unio ruber Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 257.

Unio obliqua Woon, Ind. Test. Rev., 1856, p. 200, pl. 1, fig. 8.
Differs from allied forms in its great obliquity and in usually

having rose-colored nacre. The young shells are not nearly

so oblique.

Ortmann, (1. c.), states that only the outer gills are mar-
supial and savs that “this is only an extreme form of P.
obliquum.”?

890 QUADRULA

Group of Quadrula subrotunda.

Shell solid, rounded, elliptical or ovate, with high beaks
curved inward and forward over a distinct lunule; beak sculp-
ture a few coarse ridges curved up behind; posterior ridge
feebly developed; epidermis brownish or blackish and often
painted with a few faint rays on the earlier shell, which are
disposed to break into squarish spots; hinge and teeth strong ;
secondary lateral in right valve well developed; beak cavities
deep, compressed; muscle scars deep. Animal with all four
gills used as a marsupium throughout, filled with pink ova;
gills large, inner only slightly the larger, free the greater part
of their length; anal opening crenulate or papillose.

QUADRULA BURSA-PASTORIS (B. H. Wright).

Shell irregularly ovate or subrhomboid, subcompressed to
convex, solid, inequilateral; beaks apparently not very full
or greatly elevated: posterior ridge rather low, usually widely
and faintly double; ending near the base of the shell in a bian-
gulation; anterior end rounded, sometimes truncated above;
base line curved or straight in young or adult shells, often
slightly sinused in front of the posterior ridge in old speci-
mens; outline of dorsal slope curved, sometimes subangular
behind the ligament; surface rough, having strong, irregular,
growth lines; epidermis brownish, wrinkled, dull; pseudocar-
dinals radially striate; laterals heavy, that of the right valve
somewhat double; muscle scars large, impressed; beak cavities
deep, compressed ; nacre dirty white to lead-colored, generally
with large, greenish-yellow blotches, thinner behind.

Length 110, height 77, diam. 42 mm.

Length 92, height 67, diam. 33 mm.

Clinch and Powell Rivers; Virginia and Tennessee.

Type locality, Powell River, Va.

Unio bursa-pastoris B. H. Wricut, Naut., 1896, p. 133, pl. mr.
Ouadrula bursa-pastoris SIMPSON, Syn., T900, p. 79T.

Close to O. kirtlandiana, but generally more elongated and
having more lurid nacre. The pallial iine is nearer the edge of
the shell than it is in kirtlandiana and the epidermis is more
inclined to be tawny-brown.

QUADRULA 891

QUADRULA KIRTLANDIANA (Lea).

Shell large, subrhomboid or subelliptical, subcompressed or
convex, inequilateral, solid; beaks moderately full and high;
posterior ridge varying from low to somewhat elevated, often
widely double, ending near the base of the shell in a wide,
feeble biangulation ; anterior end rounded, often slightly trun-
cate above; base line usually curved; outline of dorsal slope
usually having the angle behind the ligament; surface irregu-
larly, concentrically sculptured ; epidermis yellowish-green with
broken rays when young, becoming greenish-brown, brown or
blackish and rarely raved. when adult; pseudocardinals radially
striate; lateral of right valve partly double; beak cavities
deep, compressed; muscle scars well marked; pallial line re-
mote in front; nacre white, rarely lurid, porcellaneous, thinner
behind.

Length 120, height 8&, diam. 45 mm.

Length 126, height 88, diam. 42 mm.

Ohio, Cumberland, and Tennessee River systems ; southwest
to Arkansas; north to Wisconsin?; east through southern
Michigan.

Type locality, Mahoning River, O.

Unio kirtlandianus Lea, Tr. Am. Phil. Soc. V, 1834, p. 98, pl.
xiv, fig. 41; Obs., I, 1834, p. 210, pl. xiv, fig. 41.—HANLEY,
Biv. Shells, 1843, p. 203, pl. xx1u, fig. 27-KusteEr, Conch.
Cab. 1856, ps 165, pl. xiix, fies. 2,35 1861,.p. 214, pl. txx1,
fig. 1.—SoweErBy, Conch. Icon., XVI, 1868, pl. Lxxvit, fig.
402.

Margarita (Unio) kirtlandianus Lea, Syn., 1836, p. 34; 1838,
Pp. 23.

Margaron (Unio) kirtlandianus Lea, Syn., 1852, p. 35; 1870,
p. 56.

Quadrula kirtlandiana Simpson, Syn., 1900, p. 791.

Fusconaja kirtlandiana OrtMANN, Ann. Car. Mus., VIII,
ROU 2:p:. 245;

Unio kirklandianus HANiEy, Test. Moll., 1842, p. 203.

892 QUADRULA

The young shell is very different from that of bursapastoris,
being short, and quadrate or elliptical, smooth and rayed,
while that of the latter is long oval, and scarcely rayed. Q.
kirtlandiana is not as elongated as bursapastoris and is usually
curved on the base line.

Var. minor Simpson.

Shell smaller and more delicate in every way than the type,
not very solid, usually greenish-yellow or greenish-brown, the
young with broken rays.

Length 63, height 48, diam. 22 mm.

Length 40, height 37, diam. 20 mm.

Type locality, Various localities in the ‘Tennessee River
drainage.

Quadrula kirtlandiana var. minor SIMPSON, Syn., 1900, p. 791.

It was the opinion of the late Prof. A. G. Wetherby that this
is a form of Lea’s Unio subrotundus. It seems to me to be
too much compressed for that species, which is generally quite
inflated. Dr. Sterki believes that O. swbrotunda and kirtland-
zana should be united. ‘While they approach closely and there
may be intermediates that can scarcely be named, it seems to
me they are as distinct as most of the closely related species
of this and other allied groups.

QUADRULA SUBROTUNDA (Lea).

Shell irregularly elliptical or subquadrate in outline, subin-
flated to inflated, solid, inequilateral; beaks high, full, turned
forward over a lunule, their sculpture a few subnodular ridges
or wrinkles; anterior end obliquely truncate above, rounded
below; base line curved throughout, sometimes quite full
behind the middle of the shell; outline of dorsal slope curved,
raised almost to an angle behind the ligament; surface gener-
ally sculptured with low, wide, concentric ridges; epidermis
greenish-brown, somewhat cloth-like, usually with wide and
narrow green, broken rays in the young, which often remain
on the umbonal region in the adult shell; pseudocardinals tri-
angular, rough; lateral in the right valve disposed to be double ;

QUADRULA 893

muscle scars impressed; beak cavities rather deep, compress-

ed: nacre white, porcellaneous, thinner and slightly iridescent

_ behind.

Length &9, height 65, diam. 44 mm.

Length 74, height 65, diam. 38 m.

Length 68, height 46, diam. 30 mm.

Ohio, Cumberland, and Tennessee River systems. Reported
from Michigan and the Grand River, Ontario, but it is prob-
able that the material from these localities is not subrotunda.

‘Type locality, Ohio.

Unio subrotundus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 117,
pl. xvi, fig. 45; Obs., I, 1834, p. 127, pl. xviu, fig. 45.—
HAN LEY, Biv. Shells, 1843, p. 203, pl. xx, fig. 58. ?>CHENU,
Ill. Conch., 1858, pl. xv, figs. 1, 1a, 1b—Kuster, Conch.
Cab.,,font; p. 190, pl. LX, ne. 3.

Margarita (Unio) subrotundus Lea, Syn., 1836, p. 343; 1838, p.
22:

Margaron (Unio) subrotundus Lua, Syn., 1852, p. 35 ; 1870, p.
50.

Quadrula subrotunda Stimpson, Syn., 1900, p. 791.

Fusconaja subrotunda ORtTMANN, Ann. Car. Mus., VIII, 1912,
p. 244.

?Umio brevialis CRoucH, Ill. Int. to Lamarck, 1827, p. 16, pl.
ix, Hie. 3.

Unio personatus Conrav, New F. W. Shells, 1834, p. 71.

Unio politus Say, Am. Conch., VI, 1834.—Conrap, Monog.,
VIII, 1837, p. 67, pl. xxxvil, fig. 2—Kuster, Conch. Cab.
Unio, 1852, p. 62, pl. x1v, fig. 4.—Sowerrsy, Conch. Icon.,
XVI, 1866, pl. xxx, p. 168.

It is very hard to draw a satisfactory line between this and
QO. kirtlandiana. Both have the same scheme of coloring, but
the latter is generally larger, more compressed and has lower

beaks.

QUADRULA PILARIS (Lea).

Shell irregularly short oval, inflated, solid, inequilateral ;
beaks rather high and full, turned forward over a lunule;
anterior end generally lightly truncated above, rounded below ;

894 QUADRULA

base line rounded to almost straight; outline of dorsal slope
curved, sometimes elevated just behind the ligament ; posterior
ridge moderate, rounded; greatest diameter of the shell just
below the beaks , surface covered with rude, concentric growth
lines; epidermis concentrically wrinkled, of various shades of
dull brown or greenish-brown with faint, broken rays when
young; pseudocardinals triangular, radially striate; lateral of

the right valve inclined to be double; muscle scars small, im-

pressed ; beak cavities decidedly deep, compressed ; nacre whit-

ish, often blotched, thinner and brownish or bronzy, iridescent
behind.

Length 66, height 51, diam. 31 mm.

Tength 50, height 45, diam. 27 mm.

Tennessee and Cumberland River systems; Green River,
Kentucky ; reported from the Ohio River.

Type locality, French Broad and Holston Rivers, Tenn.

Unio polaris Lea, Pr. Am. Phil. Soc., I, 1840, p. 285; Tr. Am.
Phil. Soc., VIIT, 1842, p. 209, pl. x1v, fig. 24; Obs., III, 1842,
p. 47, pl. xiv, fig. 24.—Cuenu, Ill. Conch., 1858, pl. xxix,
figs. 3, 3a, 3b.—Kuster, Conch. Cab., 1861, p. 255, pl
LXXXVI, fig. 3—Rreve, Conch. Icon., XVI, 1865, pl. xxvit,
fig. 138.

Margaron (Unio) pilaris Lea, Syn., 1852, p. 35; 1870, p. 56.

Quadrula pilaris SIMPSON, Syn., 1900, p,. 792.

Umio lesueurianus Lea, Pr. Am. Phil..Soc., I, 1840, p. 286;
Tr. Am. Phil. Soc., VIII, 1842, p. 195, pl. vu, fig. 6; Obs.,
III, 1842, p. 33, pl. vin, fig. 6—CueEnu, Ill. Conch., 1858,
pl. xxx, figs. 4, 4a, 4b.—Kustrr, Conch. Cab. Unio, 1861,
Pp. 215, pl. xccm, he. 2:

Margaron (Unio) lesuerianus LeA, Syn., 1852, p. 353 1870, p.
56.

Closest, perhaps. to Q. subrotunda. It is a smaller species,
the young shell is more evenly curved on the dorsal slope, and
the beaks are hardly so high. The posterior part of the nacre
is usually darker.

QUADRULA 895

QUADRULA ANDREWSI! Marsh.

“Shell smooth, triangular, solid, beaks swollen, incurved,
shell very inequilateral, compressed and striate at the base;
obliquely rounded before, obtusely biangulate behind; liga-
ment rather short, light brown; epidermis reddish-brown,
maculate; growth lines numerous; rather rough; umbonal
slope slightly rounded; posterior slope flat, cordate, with very
indistinct lines from beaks to basal margin; beak sculpture un-
known; cardinal teeth thick, very much sulcate, single in
right, double in left valve; lateral teeth thick, short and slight-
ly curved; anterior cicatrices small and deep; posterior cica-
trices distinct. small and deep; shell cavity rather deep; cavity
of the beaks deep and angular; nacre silver white and irides-
cent.

Diameter 1.1, length 1.6, breadth 2 (inches). (Marsh).

Type locality, Holston River, Tenn.

Quadrula andrewsu Marsu, Naut., XV, 1902, p. T15.
Quardula andrewse Marsu, Naut., XVI, 1902, p. 8, pl. 1, upper
two figures.

“Several years ago Mrs. Geo. Andrews of Knoxville, Ten-
nessee, sent me a number of these shells. They belong to the
group of which trigonus Lea is the type, but in no way do
they resemble that species. There is no species, which they
closely resemble, except globatus Lea, but it is a very much
less inflated shell than that species, having a differently colored
epidermis, rougher and coarser growth lines; at least one-half
of the disk is covered with wide, dark green spots, and between
these rows of maculations are very narrow, dark green inter-
rupted.rays. The outline of globatus is rounded, while my
shell is triangular.”

QUADRULA BEAUCHAMPI! Marsh.

“Shell subtriangular, inflated over the umbones and beaks;
shell very thick and solid, thicker before; beaks solid, raised
and incurved; inequilateral, rounded before, obtusely angular
behind; ligament short, thick, light brown; epidermis yellow-
ish-brown; growth lines close, and very prominent, almost

896 QUADRULA

sulcate. Shell compressed at the base, slightly flattened on
the sides, umbonal slope rounded, posterior slope rather wide,
with a dark impressed line from beaks to basal margin. Beak
sculpture unknown. Cardinal teeth heavy and solid, rather
compressed, corrugate and sulcate; lateral teeth short, thick
and slightly curved. Anterior cicatrices small and deep; pos-
terior cicatrices distinct and well impressed; shell cavity wide;
cavity of the beaks deep and obtusely angular; nacre white.

Diam. 1.4, length 2.2, breadth 2.3 inches.”’ (Marsh).

Type locality, Little Tennessee River, Tenn., and Holston
River, Tenn.

OQuadrula becuchampu Marsi, Naut., XVI, 1902, p. 7, pl. 1,
lower two figures.

“T obtained three specimens from Wm. M. Beauchamp a
number of years ago; afterwards Mrs. Geo. Andrews sent me
several of them from Holston River, Tenn. They are near
globatus Lea, but were too different to place with that species.
In outline they are subtriangular, not spherical and rounded
like that species. ‘They are more solid and heavy and a larger
species than globatus. ‘They have a lighter colored epidermis,
with closer growth lines and the surface of the shell is rougher.
They need not be confounded with my andrewsii as they differ
in outline, teeth and character of the rays and are a very
much larger species and more solid and heavy. ‘They vary
greatly in character of the rays;.some are rayless, two have
obscure maculations, while some have very obscure, indistinct
rays.”

QUADRULA CUNEUS (Conrad).

Shell subovate, subinflated to inflated, more or less solid,
inequilateral ; beaks high and quite full; diameter through the
umbonai region greatest; disks flattened behind the middle
and descending wedge-shaped to the posterior extremity; an-
terior end rounded, sometimes slightly truncate above ; outline
of base and dorsal slope curved; surface with irregular, con-
centric growth lines; epidermis reddish-brown, more or less
rough; teeth heavy; lateral of right valve disposed to be

QUADRULA — 897

double; beak cavities moderately deep, compressed; muscle
scars small, impressed; nacre rich pink, thinner and iridescent
behind.

length so, height 45, diam. 33 mm.

lLength 50, height 42, diam. 26 mm.

Arkansas; Louisiana; Sabine River, Texas.

‘Type locality, Little Red River, Ark.

Unio cuneus Conrav, Monog., XII, 1840, p. 105, pl. Lvri, fig.

Pp
Quadrula cuneus SIMPSON, Syn., 1900, p. 792.

There are a number of Conrad’s species, which according
to his figures and descriptions differ from anything I have
ever been able to examine, even though in several cases I have
seen material from the type localities, and this is one of them.
Conrad’s Unio cuneus was obtained from the Little Red River,
Arkansas, and I have before me specimens from that same
stream, which are thinner, smoother, less inflated and not
so decidedly wedge-shaped as his description and figures show.
Yet I think they must be cuneus. I have seen no shells which
agree any more closely with his Unio productus, U. contrarius,
U. furvus, U. maculatus, U. perovatus, Alasmodonta radiata,
Anodonta subvexa, A. teres, etc., though I have seen examples
of what are probably a considerable number of these species.
Conrad was an excellent naturalist, but was careless and in a
number of cases his descriptions are considerably at variance
with his figures, and his localities are apparently wrong.
QuADRULA EBENUS (Lea).

Shell subquadrate or subelliptical, inflated, solid, very inequi-
lateral; beaks exceedingly high, full, turned inward and for-
ward over a lunule, their sculpture a few rather feeble corru-
gations ; anterior end squarely or obliquely truncate above un-
der the sometimes overhanging beaks, rounded below; base
rounded, straight or incurved in old shells; outline of dorsal
slope a full curve: posterior ridge rather low, often somewhat
double, curved; surface with low, irregular, concentric ridges ;
epidermis tawny-brown, reddish-brown or blackish, usually

898 QUADRULA

wrinkled ; pseudocardinals subradial, usually curved, split up

and torn; lateral of right valve disposed to be double; muscle

scars deep; beak cavities very deep, compressed; nacre white,
thinner and iridescent behind.

Length 110, height 92, diam. 60 mm.

Length 102, height 75, diam. 55 mm.

Length go, height 74, diam. 53 mm.

Mississippi drainage generally, except its western portion;
Alabama and Tombigbee Rivers; northeast Texas?

Type locality, Ohio River.

Unio ebenus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 84, pl. 1x,
fig. 14; Obs., I, 1834, p. 94, pl. 1x, fig. 14—Han ey, Biv.
Shells, 1843, p. 202, pl. xx, fig. 47——CuHeENu, III. Conch.,
1858, pl. xv, figs. 7, 7a, 7b——SoweERBy, Conch. Icon., XVI,
1868, pl. Lxvi, fig. 334.

Margarita (Unio) ebenus Lua, Syn., 1836, p. 34; 1838, p. 23.

Margaron (Unio) ebenus Lea, Syn., 1852, p. 35; 1870, p. 56.

Ouadrula ebents SIMPSON, Syn., 1900, p. 793.

Fusconaja ebena OrtMANN, Ann. Car. Mus., VIII, 1912, p.
245. ne ais

Unio obovalis Say, Am. Conch., VI, 1834.

Unio obliquus Conran, Monog., [X, 1837, p. 77, pl. xia, fig.
2.—Kuster, Conch. Cab. Unio, 1861, p. 215, pl. Lxx1, fig. 4.

Unio mytiloides Swatnson, Treatise on Mal., 1840, p. 270,
figs. 52, 53.

An abundant, widespread and variable form. It is the “‘nig-
gerhead” of button manufacturers of the Mississippi River
and the most valuable and important species used by them.
It has exceedingly full, high beaks, which are usually placed
at the extreme anterior end of the shell. The lunule is gener-
ally placed farther back than in allied species; in fact, the
beaks often project in front of it. There is sometimes a faint
secondary lunule. The young are often light ashy-brown on
the beaks with a pale or whitish area on the dorsal slope, very
different from those of any related forms.

QUADRULA 899

QUADRULA GLOBATA (Lea).

Shell suborbicular or subelliptical, very much inflated, solid,
inequilateral; beaks very full, high, apparently turned inward
and forward over a lunule; anterior end rounded or slightly
truncated ; outline of base and dorsal slope as well as the pos-
terior part of the shell rounded; posterior ridge but slightly
marked, curved; greatest diameter below the beaks, surface
with rude, irregular growth lines; epidermis dull, greenish-
brown or ashy-brown, often cloth-like, with broken, green rays
in the young shell; pseudocardinals triangular, ragged; lateral
of right valve double; beak cavities deep, compressed ; muscle
scars small, deep; nacre bluish-white, thinner and slightly iri-
-descent behind.

Length 52, height 44, diam. 35 mm.

Holston and ‘Tennessee Rivers, Tennessee; Etowah River,
Georgia.

Type locality, Holston River, Tenn.; Etowah River, Ga.
Umo globatus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 191; Jl.

Rew Sere ita. Ville hors. p 5. ply t fios Tr Obs.) DTT,

1974,(p- 9, pl. 1 Hg...

Ouadruia globata SIMPSON, Syn., 1900, p. 793.

While this form is nearly allied to OQ. subrotunda, I believe
it to be a valid species. In all the specimens I have seen the
beaks are badly eroded and the outline of the shell is either
nearly orbicular or irregularly short elliptical. The posterior
ridge is scarcely developed, the disks being almost evenly
swollen from the anterior to the posterior ends. The hinder
end of the shell is nearly evenly rounded, and in all these
characters it differs from subrotunda, pilaris or any of the
allied forms. The name globata is very appropriate.

Group of O. glandacea.

Shell rhomboid-oval, nearly straight below and slightly bi-
angulate behind, with a well-defined double posterior ridge;
beaks probably full; surface slightly and irregularly sulcate;
epidermis wrinkled, tawny; hinge strong, the plate somewhat

goo QUADRULA

flattened; pseudocardinals triangular; laterals strong, second-
ary lateral of right valve well developed; beak cavities deep,
compressed; muscle scars very deep, smooth; nacre dirty
straw-color.

QUADRULA GLANDACEA (Lea).

Shell subrhomboid, or rhomboid-oval, somewhat inflated,
rather solid, inequilateral; beaks probably full and high; pos-
terior ridge well developed, usually narrowly double, ending
below in a blunt point or a biangulation ; anterior end rcunded,
sometimes slightly truncate above; base line straight; outline
of dorsal slope curved or raised into an angle behind the liga-
ment; surface with rude, irregular growth lines; epidermis.
wrinkled, tawny, scarcely shining; pseudocardinals triangular,
strongly radially striated; muscle scars small, impressed; beak
cavities deep and compressed: nacre whitish or straw-colored,
thinner and iridescent behind.

Length 50, height 38, diam. 26 mm.

Coosa and Cahawba Rivers, Alabama.

Type locality, Cahawba River, Ala.

Unio glandaceus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 593.
Ji. Ac. N. Sc.) Phila. "V, 1862, p:.77,. pl. 1%, n¢.2220; taps.
VILE: p. Sty pl. rx, fas. 226,

Margaron (Unio) glandaceus Lea, Syn., 1870, p. 38.

Quadrula glandacea SIMPSON, Syn., 1900, p. 793.

I have seen but a limited amount of material of this peculiar
species. It has the texture, form and coloring of many of the
members of the genus Pleurobema, but the beak cavities of all
the specimens I have seen are deep and compressed and this
would indicate that it is a Quadrula. In two of the shells ex-
amined there is a slight, radial groove on the dorsal slope but
I do not know whether this is a constant character. There is
a somewhat eroded valve in the national museum collection
donated by Dr. Powell, labeled “Arkansas” which is marked
“Unio glandaceus” by Dr. Lewis. While it may be that species,

I am a little in doubt concerning it.

QUADRULA gol

Section PAcHyNAIAsS Crosse and Fischer, 1893.

Pachynaias Crosse and iscHer, Miss. Sci. Mex., Moll., 1893,

p. 550.

Shell elongate-triangular, inflated, truncated above and
rounded below in front, straight on the base, with a high,
sharp posterior ridge; the post-base slightly biangulate; beaks
full, the sculpture consisting apparently of faint ridges, which
run parallel with the growth lines; whole surface distinctly
concentrically ridged ; epidermis without rays; pseudocardinals
solid, stumpy, somewhat radiate, roughened; beak cavities
rather deep; muscle scars deep, smooth; nacre bluish-white,
thicker in front.

Animal unknown.

Type, Unio spheniopsis Morelet.

QUADRULA SPHENIOPSIS ( Morelet).

Shell subtriangular, subequilateral, solid, inflated, with a
high, sharp posterior ridge and 2 low fainter one not far above
it, with a high umbonal region though the beaks are not very
prominent; beak sculpture appearing to consist of concentric,
irregular ridges much like the strong, rather sharp, irregular
sculpture that covers the shell throughout ; epidermis greenish-
yellow or yellowish-green, showing a few faint rays behind;
left valve with two short, remote laterals, the lower higher;
hinge plate between the two sets of teeth somewhat narrowed
and rounded; right valve with one strong pseudocardinal and
a vestigial one above and one lateral; beak cavities deep,
scarcely compressed; muscle scars distinct, the anterior ones
deep ; pallial line deep; nacre whitish or bluish-white, thicker
in front.

Length 60, height 47, diam. 35 mm.

Rio Usumacinta, Guatemala; State of Tabasco, Mexico.
Unio spheniopsis Morrier, Test. Nov., I, 1849, p. 29.—Fiscu-

ER and Crosser, Miss. Sci., IT, 1894, p. 583, pl. Lxt, figs. 2,

2a, 2b.

Ouadrula spheniopsis Stupson, Syn., 1900, p. 794.

The specimen figured by Fischer and Crosse in the Mission
Scientifique is not quite adult. The measurements given above

go2 QUADRULA

are from a shell taken in the Usumacinta River, Guatemala,
and sent to the National Museum by von Ihering. The Na-
tional Museum has still larger specimens from Tabasco, Mex-
ico. It is shorter, more inflated, and solider than the nearly
allied rugososulcata and the pallial line is closer to the shell
border than it is in that species.

QUADRUILA RUGOSOSULCATA (Lea).

Shell elongately triangular, subequilateral, rather inflated
and solid, with a sharp, double posterior ridge, the lower ridge
decidedly angled, the upper less pronounced; truncated above
and rounded below in front; the base line nearly straight ;
beaks high and moderately full, their sculpture consisting of
rather fine bars running nearly parallel with the growth lines;
surface closely and rather sharply, concentrically sculptured
throughout; epidermis dirty greenish-brown, darker above,
somewhat wrinkled; left valve with two stumpy, radial pseudo-
cardinals and two laterals, the lower larger; the hinge plate
flattened under the beak and narrowed behind; right valve with
one pseudocardinal, a small tooth in front of it and a vestigial
one behind it; beak cavities rather deep, scarcely compressed ;
anterior scars very deep; posterior scars large and impressed ;
pallial line deep and broken, distant from the edge of the shell
in front ; nacre bluish-white, thicker in front.

Length 80, height 57, diam. 35 mm.

Central America.

Unio rugososulcatus. Lex, Pr. Ac. N. Sci. Phila., X, 1866, p.
235 ji Aco NSci- Phila.,- Vij 1868, sp. 260, pl aamciy tie eee
Obs:; STL 1 860,2p- 26, pr xexociy ieee

Margaron (Unio) rugososulcatus LeA, Syn., 1870, p. 35.

OQuadrula rugososulcata SIMPSON, Syn., 1900, p. 794.

A fine species, the type being in the Lea Collection. Signor
Paz sent Lea two shells, one of which Lea kept and the other
he returned. The locality “Central America” is written inside
the left valve of Iea’s shell. It is longer and less inflated than
O. spheniopsis, to which it seems to be nearly related and is
not so heavy as that species.

QUADRULA 903

Subgenus RoruNDARIA (Rafinesque, 1820) Simpson.

Rotundaria RAFINESQUE, Am. Gen. Sci. Phys. Brux., V, 1820,
p. 308.—OrtTMANN, Ann. Car. Mus., VIII, 1912, p. 257.
Shell rounded or quadrate, slightly truncate above in front ;

posterior ridge low; beaks prominent, curved inward and for-
ward over a strongly marked lunule; beak sculpture consist-
ing of numerous (20 to 30) fine, irregular, broken, somewhat
concentric corrugations, which extend well on to the second
year's growth and gradually blend with the regular sculpture ;
posterior three-fifths of the shell tuberculate ; epidermis brown ;
beak cavities very deep, compressed ; nacre violet.

Animal having the gills very large, inner very much wider
in front, free the whole length from the abdominal sac; bran-
chial opening immense, with many small papillz; anal open-
ing very large, smooth; superanal opening not at all closed
below.

Type, Obliquaria tuberculata Rafinesque.

Ortmann, (1. c.), raises this group to generic rank.

Group of Quadrula tuberculata.

Shell rounded, truncated behind, with a wide depression
down the post slope.

QUADRULA TUBERCULATA (Rafinesque).

Shell subelliptical to subquadrate, subcompressed or only
slightly inflated, inequilateral, solid or ponderous; beaks ele-
vated but not inflated, turned forward, rather sharp, their
sculpture consisting of numerous fine, corrugations that are
sometimes broken and doubly looped or zigzagged; anterior
end usually evenly rounded; base. line curved; posterior end
squarely or obliquely truncated with a well-marked sinus above
the posterior ridge, usually angled behind the ligament; pos-
terior ridge low, above it is a wide radial depression that ends
in a notch or sinus; posterior three-fifths of the shell more or
less tuberculate; anterior third concentrically sculptured; epi-
dermis reddish-brown or greenish-brown, scarcely shining;

904 QUADRULA

hinge plate wide and flat, pseudocardinals ragged; lateral of
right valve more or less double; beak cavities very deep, com-
pressed; muscle scars well marked; pallial line remote; nacre
various shades of purple, thinner behind.

Length 136, height 104, diam. 50 mm.

Length 125, height 111, diam. 55 mm.

Iength go, height 80, diam. 42 mm.

Mississippi drainage generally; southern Michigan; San
Saba County, central Texas. —

Type locality, Ohio River and adjacent streams.

Obliquaria (Rotundaria) tuberculata RAFINESQUE, Ann. Gen

Sci. Brux., V, 1820, p. 103.

Rotundaria tuberculata Acasstz, Arch. fur Naturg., I, 1852,

p. 48.—OrTMANN, Ann. Car. Mus., VIII, 1912, p. 258, fig. 7.
Unio tuberculatus Conrap, Monog., V, 1836, p. 43, pl. Xx11.—

Kuster, Conch. Cab. Unio, 1852, p. 45, pl. 1x, fig. 1—REEVE,

Conch); Tcon., X Vi) 1864. pl. om tissG, i:

Quadrula tuberculata SIMPSON, Syn., 1900, p. 795..
Unio verrucosus BARNES, Am. J]. Sci., VI, 1823, p. 123, pl. v,

fig. 6—Hantsy, Biv. Shells, 1843, p. 180, pl. xx1, fig. 24.
Margarita (Unio) verrucosus Lma, Syn., 1836, p. 16; 1838,

Del 5:

Margaron (Unio) verrucosus Lea, Syn., 1852, p. 22; 1870,

Pp. 34.

Unio verrucosus purpureus Hirpreru, Am. Jl. Sci., XTV, 1828,

p. 281.

Mya verrucosa Eaton, Zool. Text-Book, 1826, p. 216.
Ouadrula verrucosa BAKER, Mol. Chicago, Pt. 1, 1898, p. 85,

Pl Orie:

Unio tuberculosa VALENCIENNES, Rec. Obs. Zool. Anat., IT,

1O225 232)

This has usually been placed in the pustulosa group, but the
character of the beak sculpture, a large number of fine, often
broken, zigzagged corrugations reaching well out over the
disk seems to separate it quite distinctly from that assemblage
and ally it to a number of Mexican and Central American

QUADRULA 995

forms. The distinct radial furrow on the dorsal slope, ending
in a notch or sinus below and the enormous anal and branchial
openings of the animal are good characters.

It has been quite generally believed that the Unio gran-
iferus of Tea is merely the young, or a small form of this
species, but it seems to me perfectly distinct. It is a much
smaller, more inflated, brighter colored form and the nacre is
usually differently tinted.

I greatly regret that the well-known name verrucosus of
Barnes must be changed for the less known tuberculatus of
Rafinesque. His description of tuberculatus applies to this
species and cannot be made to cover any other.

QUADRULA GRANIFERA (Lea).

Shell suborbicular or subquadrate, inflated, solid, somewhat
inequilateral; beaks high, full; anterior end and base usually
rounded ; posterior end truncated, often slightly sinused above
the posterior ridge; posterior ridge moderately developed ;
above it there is a light, radial depression ; posterior two-thirds
of the shell with coarse, scattered tubercles; anterior third
without tubercles ; epidermis greenish-brown to reddish-brown,
usually somewhat shining; hinge plate wide; pseudocardinals
radial, torn; laterals short, straight, that of the right valve
partly double; beak cavities very deep, compressed; nacre
purplish, often coppery and shining.

Length 60, height 60, diam. 35 mm. ~

Length 46, height 50, diam. 33 mm.

Ohio, Cumberland, and ‘lennessee River systems ; northwest
to Iowa.

Type locality, Ohio River, Cincinnati, O.

Unio graniferus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 60, pl.
xIx, fig. 60; Obs., II, 1838, p. 69, pl. x1x, fig. 60.—HANLEY,
Biv. Shells, 1843, p. 180, pl.. xxt, fig. 11—CueENu, IIl.
Conch., 1858, pl. xxv, figs. 3, 3a, 3b—Kuster, Conch. Cab,
Unio, 1861, p. 212, pl. Lxx, fig. 4.—Rkreve, Conch. Icon.,
XVI, 1864, pl. 1x, fig. 34.

Margarita (Unio) graniferus Lea, Syn., 1838, p. 15.

go6 QUADRULA

Margarcn (Unio) graniferus Lea, Syn., 1852, p. 22; 1870, p.

34-

Quadrula granifera SIMPSON, Syn., T900, p. 795.

Smaller, more inflated, usually brighter, higher in propor-
tion to length, with stronger tubercles, more coppery nacre
and a less remote pallial line than tuberculate. The young of
that species are compressed as are the adults.

Var. pusilla Simpson.

Much smaller than the type, with an angled posterior ridge,
which ends in a point; posterior furrow deeper than in the
type; epidermis less smooth.

Length 34, height 32, diam. 22 mm.

Type locality, Green River, Ky.

Quadrula granifera var. pusilla SIMPSON, Syn., 1900, p. 795.

Were it not for the fact that a dwarf form of Cyprogenia
irrorata was found with this form, I should be inclined to give
it specific rank. It is more elongated than the granifera and
the tubercles are sharper. |

Group of Ouadrula ostreata.

Shell rhomboid, incurved on the base, with a well-developed
posterior ridge, somewhat biangulate behind; beak sculpture
consisting of a number of fine, concentric ridges showing a
tendency to be doubly looped, which gradually change, first to
corrugations and then to pustules; pseudocardinals ragged;
secondary lateral of right valve but slightly developed.

Animal unknown.

QUADRULA OSTREATA (Morelet).

Shell subtriangular, inequilateral to subequilateral, some-
what inflated, solid in front, thinner behind, with a very high
umbonal region, the beaks curved inward and forward: beak
sculpture faint, consisting of slight doubly-looped ridges ; pos-
terior ridge well developed, double, the lower ridge strong and
angular; base rounded, incurved behind in old shells; surface
covered with rather strong, irreguiar, concentric ridges and

QUADRULA 907

nodulous generally throughout; epidermis yellowish-brown
to ashy in young shells, darker in old shells; left valve with
two rather high, subcompressed pseudocardinals, the anterior
one elongated, and there is an indication of a low ragged tooth
below and between them, with two nearly straight laterals, the
lower larger; right valve with a ragged, solid, but somewhat
compressed, pseudocardinal ; sometimes there is a second tooth
above it and again it is wanting, and one lateral, which shows

a tendency to split a little; beak cavities deep, compressed ;

anterior scars ragged; posterior scars round and _ shallow;

pallial line distant from the border; nacre pale purplish, sal-
mon-rose or deep coppery.

Length go, height 73, diam. 48 mm.

Length 80, height 64, diam. 37 mm.

Length 68, height 63, diam. 37 mm.

Guatemala: Tabasco, Mexico.

Unio ostreatus Moreier, Test. Noviss., 1849, p. 290.—FISCHER
and Crosse, Miss. Sci., IJ, 1894, p. 573, pl. xi, fig. 3; LXx,
fig. 4.

Quadrula ostreata SImPpson, Syn., 1900, p. 796.

Fischer and Crosse have figured a young, very high shell in
the Mission Scientifique. As the species grows older it be-
comes elongated and drawn down at the posterior base. ‘This
is more triangular, more solid, and inflated than guadrata and
is in every way a more robust shell.

QUADRULA PROFUNDA N.. S.

Shell irregularly triangular or trapezoidal, very inequilateral,
solid in front and thinner behind, inflated, the umbonal region
greatly elevated: beaks strongly turned inward and forward,
but rather remote from each other, their sculpture not ob-
served; lunule large, truncate in front, extending under the
beaks; posterior ridge high, curved, angled with a faint ridge
behind it and a shallow, wide radial furrow in front of it and
ending at the base in a blunt point; post-dorsal line almost reg-
ularly curved from the umbonal region to the posterior base;
anterior outline in the form of an ogee, rounded below, in-
curved sharply above to the overhanging beaks, base line in-

908 QUADRULA

curved behind; surface covered with strong, irregular, con-
centric, nodulous ridges; epidermis greenish-brown, much de-
corticated in the only shell seen; left valve with a long, curved
upper pseudocardinal formed no doubt by the union of two
teeth, and a small ragged tooth below it and two remote, curved
laterals, the upper very small; beak cavity enormous and pro-
found, not compressed; dorsal scars at the base of the pseudo-
cardinals; posterior scars shallow; anterior scars ragged;
nacre whitish, pink-tinted.

Length 77, height 64, diam. 55 mm.

Usumacinta River, Guatemala.

The National Museum possesses a single valve of this ro-
bust species presented by Dr. von Ihering. I at first referred
it to the Unio usumasinte with doubt, but I am now satisfied
that it is not that, but an undescribed species. It is much more
rudely sculptured than that species and has a totally different
epidermis, the beaks are nearer the anterior end of the shell,
and the outline below them is an ogee, while it is truncate
above in usumasinte. Its beaks are turned farther forward
and the enormous beak cavity is much deeper. On account of
this immense and deep cavity I have called it Quadrula pro-

funda.

QUADRULA USUMASINTA (Crosse and Fischer).

Shell subtriangular, inflated, very solid, cordiform with a
high umbonal region greatly raised above the hinge; beaks
turned upward and forward over a wide lunule; anterior end
slopingly truncate above, rounded below; posterior end slop-
ingly truncate; posterior ridge distinctly double, ending in a
biangulation just at and above the base; beak sculpture con-
sisting of rather fine, irregular, subnodulous ridges; this grad-
ually passes into the strong, irregular, concentric sculpture
covering the shell, these ridges are granular in front and fee-
bly subnodulous behind; on the posterior slope there are radial,
nodulous wrinkles and a few faint, radial folds on the front
part of the shell; ligament long, brown; epidermis ashy or
ashy-brown; hinge very strong; left valve with two large, con-

QUADRULA 909

nected, torn pseudocardinals and two curved, heavy laterals,
the lower larger; right valve with two pseudocardinals, the
lower very large, the upper long and compressed and one
strong lateral with a vestige of another above and a third be-
low it; beak cavities very deep, not compressed; dorsal scars
in a long row under the pseudocardinals; muscle scars deep,
the anterior ones very rough; pallial line distant from the bor-
der in front; nacre rose-colored to deep coppery-purple, very
much thickened in front.

Length 82, height 70, diam. 55 mm.

Guatemala in the Usumacinta River; Tabasco, Mexico.
Unio usumasinte Crossr and Fiscrer, J. de Conch., XL, 1892,

p. 294.—-Fiscurr and Crosse, Miss. Sci., I, 1894, p. 574,

piss Perino 4 5 Lxvit, fig, 5:

Ouadrula usumasinte SIMPSON, Syn., 1900, p. 796.

The specimen figured by Fischer and Crosse is young and
has a pink nacre. I have seen a fine adult specimen of what
is undoubtedly this species, which is one of the most robust
in the development of its parts of any Naiad | know of. It is
larger, more inflated, and solider than Q. ostreata.

QUADRULA GUATEMALENSIS Simpson.

Shell subrhomboid, longer than high, inequilateral, subcom-
pressed, subsolid, with moderately high, but not swollen, beaks,
whose sculpture is eroded in the only specimen seen; anterior
end narrowed, subangular, rounded in front; posterior ridge
low, double, ending in a feeble biangulation behind at the base*
of the shell; surface with rather close, irregular, nodulous, con-
centric sculpture; epidermis brown, lighter behind, rayless;
left valve with two subcompressed pseudocardinals and one
lateral with a vestige of another above it; right valve with a
ragged pseudocardinal and one curved lateral; beak cavities
only moderately deep; anterior muscle scars impressed; pos-
terior scars shallow; nacre coppery-purple, slightly iridescent
behind, thicker in front.

Length 45, height 28, diam. 14 mm.

Rio Usumacinta, Guatemala.

gI10 QUADRULA

Quadrula guatemalensis Simpson, Pr. Acad. N. Sci. Phila.,

1900, p. 83, pl. 11, fig. 4; Syn., 1900, p. 796.

This has a more elongated form than any member of the
group, but it seems to show rather close relationship to Q.
quadrata. The general external appearance of the shell and
its comparatively shallow beak cavities lead me to believe that
it is rather young. It differs from Q. quadrata in being more
elongated, and compressed, in being lighter colored behind, in
the shallower beak cavities. color of nacre and size.

(QQUADRULA RUDIS Simpson.

Shell elongated, somewhat rhomboid, rather inflated, very
solid in front but much thinner behind, with a rather sharp,
curved posterior ridge, which ends in a blunt point at the base
line and there is an indication of a faint secondary ridge on
the posterior slope; dorsal line curved rather regularly from
the beaks to the post-base; basal line incurved behind; anterior
end rounded; umbonal region very high, the beaks curved in-
ward and forward but not approaching, their sculpture seem-
ing to be nodulous, irregular ridges; lunule well marked and
passing under the beaks; surface covered with rather close
pustules, which gradually change at the border of the shell to
slightly nodulous, irregular sulcations; epidermis brown, the
only specimen seen nearly decorticated; left valve with three
rather strong, but illy separated, ragged pseudocardinals, there
being a deep crater between the lower and anterior teeth; lat-
erals two, the lower the larger; right valve with one large
pseudocardinal and one lateral; beak cavities very deep, sub-
compressed ; dorsal scars in a row at the base of the pseudo-
cardinals; anterior muscle scars very rough; pallial line deep,
distant from the border, nacre cream-colored.

Length 113, height 65, diam. 46 mm.

Rio Taxtunilha, tributary of Rio de la Pasion, Guatemala
Quadrula rudis Stmpson, Pr. Ac. N. Sci. Phila., 1900, p. 82

DENI, hes 2:

Unto crocodilarum var. rudis von Martens, Biol. Cent. Amer.

Moll., t901, p. 648.

QUADRULA gII

Lea received the only specimen I have seen, the type from
Wheatley, who had labeled it Unio psoricus. It differs most
decidedly from that species, being longer, more inflated, dif-
ferent colored, and having much deeper beak cavities. This
species was overlooked by accident when making up the Syn-
opsis.

QUADRULA QUADRATA 0. S.

Shell subquadrate, subcompressed to convex, rather solid;
beaks located subcentrally or near the anterior end, rather high
but compressed and turned inward and forward; posterior
ridge rather low, wide and double; posterior end subtruncated ;
base slightly incurved behind; surface covered with small pus-
tules and irregular, low, concentric ridges; epidermis dirty
brown, in places tinted with bottle-green, decorticated on the
nodules ; left valve with two strong, low, ragged, radial pseudo-
cardinals with an imperfect, much torn tooth between and two
small laterals; right valve with one ragged pseudocardinal
and one lateral, partly divided ; beak cavities deep, compressed ;
anterior scars rough; pallial line distant from the shell border ;
nacre creamy-white.

Length 67, height 55, diam. 33 mm.

Length 72, height 53, diam. 27 mm.

Length 60, height 50, diam. 30 mm.

Usumacinta River, Guatemala.

The National Museum possesses three specimens sent by
Dr. von Ihering from the above locality, which I at first doubt-
fully considered to be the Unio ostreatus of Morelet and one
of them has something of the outline of that species. In gen-
eral it is much more quadrate, it is a smaller and more delicate,
more compressed species and the pseudocardinals are very
different. Those of quadrata are low and rather wide, while
in ostreata they are high and subcompressed. The National
Museum recently received a fine series of ostreata from
Messrs. Nelson and Goldman, collected in southern Mexico,
and the difference in the two species is at once apparent.

gt2 QUADRULA

QUADRULA PERCOMPRESSA (von Martens).

Shell large. triangular or subtriangular, solid, greatly com-
pressed, with very high beaks, whose sculpture has not been
examined; equilateral or inequilateral; posterior ridge nar-
rowly biangulate ; anterior slope often incurved above, rounded
below ; posterior slope rounded ; surface with strong, nodulous,
concentric ridges; in some cases the ridges become almost re-
placed by nodules; epidermis pale brownish, the surface gen-
erally nearly decorticated ; left valve with two low, solid, radial,
rough pseudocardinals and one lateral with a vestige of a sec-
ond above it; right valve with a large, somewhat divided, pseu-
docardinal and one lateral; hinge plate very wide and flat and
on it there is a wide epidermal deposit under the beaks, which
often covers the entire width of the plate; beak cavities very
deep and compressed ; anterior scars shallow, rough; posterior
scars rather long ; nacre varying from whitish to purple, great-

ly thickened in front; pallial line remote from the shell border
in front.

Length rto, height 96, diam. 25 mm.

Leneth 94, height 92, diam. 28.5 mm.

Length 95, height 73, diam. 24 mm.

Rio Usumacinta and Rio de las Salinas, Guatemala.

Unio percompressiis VON MARTENS, Sitzungs Ber. Nat. Tr.
1887, p. 107; Biol. Cent. Am. Moll., p. 406, pl. xxxm, figs.
1-3.

Ouadrula percompressa SIMPSON, Syn., 1900, p. 796.

A remarkable shell, of which two large, teft valves are in
the National Museum, both of which turn to the left in front
and to the right behind. From an examination of these re-
markable valves I believed it best to give the species the rank
of a group, but the figures, which von Martens has lately pub-
lished in the Biologia, show much variation in the species and
that it varies towards QO. quadrata and ostreata. I therefore
place it in the same group with these species. It cannot be
mistaken for any known form.

QUADRULA 913

Subgenus LAMPROTULA Simpson, 1900.

Lamprotula S:MPsSoNn, Syn., 1900, p. 796.

Shell rounded to triangular, inflated, with high beaks; beak
sculpture consisting of a few coarse, subparallel ridges, which
are slightly doubly looped; surface of the shell generally cov-
ered with coarse nodules or knobs; posterior slope radially
ridged; epidermis dark; hinge strong; secondary lateral of
right valve well developed; cavity of the beaks deep and com-
pressed: nacre mostly whitish, usually radially, granularly
striated outside the pallial line, and having one or more pecu-
liar calluses behind and below the laterals, which are iridescent
and granularly striate.

Animal unknown.

Type, Chama plumbea Chemnitz.

Group of Ouadrula plumbea.

Shell rounded, slightly angulated behind the ligament, solid,
moderately inflated, covered with coarse pustules, and having
broken, upcurved corrugations on the posterior slope; epider-
mis light brownish; hinge rather strong, somewhat flattened ;
laterals vertically striated.

QUADRULA PLUMBEA (Chemnitz).

Shell suborbicular, solid, somewhat inflated, inequilateral ;
beaks moderately high, turned forward; surface sculptured
with oblique corrugations in the umbonal region, which de-
scend toward the anterior base, having irregular, radial folds
below and behind; the basal and anterior parts of the shell are
somewhat tuberculous; epidermis brownish; hinge plate wide
and flat; pseudocardinals very strong; laterals with strong
vertical striation; beak cavities no doubt deep; nacre white.

Length of figure 42. height 45 mm.

South East Asia, probably. The locality, “South Sea,” given
by Chemnitz is, no doubt, erroneous.

Chama plumbea CurmMnitz, Conch. Cab., XI, 1795, p. 237, pl.
ccul, figs. 1991, 1992.—Woon, Ind. Test. Rev., 1856, p. 52,
pl. rx. fig. 6.

Ouadrula plumbea Stmevson, Syn., 1900, p. 797.

gt4 QUADRULA

Unio plumbeus Kuster, Conch. Cab. Unio., 1862, p. 289, pl.
KEVIL Ss) Le 2:
Chemnitz’ figures are not carefully finished and they, no
doubt, give an erroneous representation of the pseudocardinals.
The outline is nearly orbicular ; the shell is evidently very solid.

QuAPRULA COREANA (von Martens).

Shell subelliptical, inequilateral, not inflated, rather solid;
beaks moderately full and elevated, their sculpture not ob-
served; posterior ridge moderately developed, rounded; sur-
face strongly sculptured, there being a row of heavy chevron-
shaped folds down the posterior ridge, while the anterior end
_ 1s somewhat pustulous ; epidermis yellowish-green, with green-
ish cloudings; left valve with two radial pseudocardinals, the
hinder heavier, and two remote, delicate laterals; right valve
with one pseudocardinal and two vestigial ones, with one
vertically striate, slender lateral; anterior scars small, poste-
rior scars faint; beak cavities very deep, compressed; nacre
white, thinner behind.

Length 43, height 36, diam. 21 mm.

Seoul, Korea.

Unio coreanus von Marvrens, S. B. Nat. Fr., 1886, p. 78;

Zool. Jahrb. Suppl., VIII, 1904, p. 50, pl. m1, fig. 5.
Ouadrula coreana SIMPSON, Syn., 1900, p. 797.

“Among the Chinese species figured by Heude, Unio affinis,
(Ouadrula similaris Simpson), is the nearest to this Korean
species, but in the Chinese species the anterior end is much
shorter, so that the form is in a general way more triangular,
the folds of the posterior portion are stronger and less nu-
merous, the tubercles are arranged in concentric rows and are
longer in this direction; towards the beaks the rows are
oblique.” (von Martens).

A single specimen belonging to the collection of Mr. Fred-
erick Stearns, from Seoul, Corea, which seems to be von
Martens’ species, is here described. ‘The specimen was taken
dead and the surface is slightly worn. It is apparently a more
compressed, less solid species than the Chama plumbea of
Chemnitz, to which it seems to be closely related.

QUADRULA 915

Group of Quadrula messageri.

Shell subquadrate, almost squarely truncated behind, having
a few wavy, almost longitudinal folds on the upper part of the
disk.

QUADRULA MESSACERL (Bavay and Dautzenberg).

Shell subquadrate, solid, inflated, inequilateral, with low,
but apparently inflated, beaks, whose sculpture is not known ;
posterior ridge full and rounded, ending behind at or near the
base line; above it there is a wide, very shallow, radial de-
pression; posterior end of the shell almost squarely truncated ;
dorsal and basal lines slightly and similarly curved toward the
somewhat narrow, rounded anterior end; surface sulcated an-
teriorly, nearly smooth behind and below, having a number
of rather strong, wavy, almost longitudinal, folds on the upper
part of the disk; epidermis yellowish-brown, faintly rayed ;
pseudocardinals ragged; laterals curved; nacre whitish, tinted
bronze.

Length 44, height 31, diam. 20 mm.

Lang-Son and That-Khe, Indo-China.

Unio messageri BAvAy and DautTzeNBERG, Journ. de Conch.,

OLEXS 1001; pay) pl: 1.figss 3,4.

Protunio messageri Haas, Conch. Cab. Unio, 1912, pl. 32, figs.

T-2.

Apparently a Ounadrula related to the Chinese forms and
bearing some resemblance to depauperate, rather smooth,
specimens of O. undulata and perplicata of the Mississippi
Valley. The strong longitudinal or very slightly oblique folds
on the upper part of the disk recall the American species.

Haas has recently, (Nachr. Deutsch. Mal. Ges., 1913, p. 37),
made this species the type of a new genus, Protunio.

Group of Quadrula nodulosa.

Shell very solid, oval or rounded, inflated, inequilateral, in-
equtivalve, the valves more or less twisted on their axis or hav-
ing the appearance as if one of them had been pushed for-
ward on the other, so that a dorsal view shows the outline to

g16 QUADRULA

be rhomboid: each valve with a posterior ridge, that on the
valve pushed forward less developed; beaks high, full, appar-
ently sculptured with a few coarse, irregular ridges; posterior
slope usually having strong, radiating, upcurved ridges; hinge
plate generally wide and flattened; pseudocardinals heavy,
somewhat radiate, often with the sockets evenly, radially
grooved; laterals strong, heavily vertically ridged; secondary
lateral of right valve well developed; anterior cicatrices small,
deep, posterior shallow ; cavity of the beaks enormously deep,
compressed ; dorsal cicatrices on the under side of the shell.
Animal unknown.

QUADRULA TORTUOSA (Lea).

Shell subelliptical, inequivalve, very inequilateral, twisted,
inflated, solid; beaks prominent, terminal, swollen; anterior
end cut away below; base line curved; outline of posterior end
curved and cut away below; dorsal slope with a gently curved
outline; left valve pushed either forward or back on the right;
posterior ridge strongest on the valve projecting behind; dor-
sal slope having subradial, curved, broken corrugations; sur-
face with concentric growth lines but lacking nodules; epider-
mis somewhat silky when fresh, ashy-brown; pseudocardinals
large, heavy, elongated, running almost parallel with the hinge
line, a heavy posterior and a smaller split one in the left valve
with one in the right valve; lateral of right valve single or
partly double, vertically striate; anterior muscle scars small,
deep ; beak cavities very deep, compressed ; nacre silvery white.

Length 67, height 47, diam. 35 mm.

Length 72, height 46, diam. 37-mm.

China.

Unto tortuosus Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 76;
Jl. Ac. Ny Set Phila.; Vi, 1868; ps 286.) pl xxx, fis es
Obs., XII, 1860, p. 46. pl. xxx1x, fig. 98.

Margaron (Unio) tortuosus Les, Syn., 1870, p. 30.

Ouadrula tortuosa SIMPSON, Syn., 1900, p. 798.

Unio (Lampsilis) subtortus Barry and Apams, Proc. Zool.
Soc. Lond., 1867, p. 491, pl. xxv1, figs. I, Ta.

QUADRULA 917

Unio subtortus SowERBY, Conch. Icon., X VI, 1868, pl. LXxxvu,
fig. 465.—Herupbr, Conch. Fluv. Nank., VIII, 1883, pl. Lx1,

fig. 1109.
Unio retortus Heupr, Conch. Fluv. Nank., VIII, 1883, pl. ivi,
fig. 100.

Two examples of this species are before me, one agreeing
perfectly with Dr. Lea's figure, the other differing a little. In
one of these the right valve is pushed forward; in the other
it is pushed back. The line of junction of the valves is curved
somewhat. It differs from the allied forms in having the disk
free of nodules and has stronger plications on the posterior
slope than fibrosa or tientsinensis.

It is quite probable that when a large amount of material
can be examined some of the species of this group will have
to be relegated to the svnonymy.

QUADRULA TIENTSINENSIS (Crosse and Debeaux ).

~

“Shell almost evenly elliptical, solid, inflated, one valve de-
cidedly pushed ahead on the other; beaks full and high, sub-
terminal; surface sculptured with strong, irregular, concen-
tric ridges and having in the umbonal region a number of tu-
bercles; epidermis silky, russet or ashy brown, painted with
bright, green, narrow bands and small blotches ; pseudocardi-
nals strong, striate and crenulate; laterals with vertical stria-
tion; beak cavities deep; nacre whitish at the border, yellow-
ish in the center of the shell.

Length 65, height 53, diam. 41.5 mm.

China.

Unio tientsinensis Crosse and Drpeaux, Jl. de Conch., III,
1863, p. 257, pl. x, fig. 1—Sowerpy, Conch. Icon., XVI,
1868, pl. xct, fig. 514, 5340, 5140.

Margaron (Unio) tientsinensis Les, Syn., 1870, p. 30.

Quadrula tientsinensis Stimpson, Syn., 1900, p. 708.

Much more evenly elliptical than tortuosa, the sculpture con-
sisting of concentric ridges and nodules being very different.
Q. tortuosa is uniformly colored, while Crosse and Debeaux’
species is painted with green, their shell has yellowish nacre
and that of tortwosa is silvery.

gis QUADRULA

QUADRULA ZONATA (Heude).

Shell long elliptical, solid, inflated, transversely oblique;
beaks terminal, full; posterior ridge only moderately devel-
oped; surface with irregular, concentric ridges and more or
less nodules on the disk ; posterior slope with a few subradial,
curved plications, which are more or less subnodulous; epi-
dermis bright, rich chestnut, sometimes slightly rayed, with
lighter color; pseudocardinals radial, elongated, radially fold-
ed or ridged; laterals with vertical striation; beak cavities
deep, compressed ; nacre white.

Tength 75, height 55, diam. 40 mm.

China. |
Unio sonatus Heung, Conch. Fluv. Nank., VIII, 1883, pl. uxt.
OQuadrula zonata SiMPSON, Syn., 1900, p. 798.

Unio tientsinensis Heupr, Conch. Fluv. Nank., VIII, 1883, pl.
i xige Lis: ‘
Very close to tientsinensis, but it has higher, larger, more

decidedly terminal beaks. the color of the epidermis is differ-

ent, the concentric ridges are wider and more feeble and the
pseudocardinals are longer.

QUADRULA FIBROSA (Heude).

Shell somewhat elongated, irregularly triangular, solid, in-
flated, the valves asymmetrical ; beaks full, high, and terminal ;
anterior end much cut away below the beaks, its outline slight-
ly curved; base line curved; outline of the dorsal slope a long,
low curve; posterior ridge only moderately developed, round-
ed; surface with irregular, concentric, nodulous ridges; epi-
dermis olive-green or olive-brown; pseudocardinals curved,
elongated, roughened; laterals curved, strongly vertically stri-
ate; beak cavities excessively deep, compressed ; anterior scars
deep, narrow, partly filled with rough nacre; nacre white, the
posterior calluses strong.

Length 117, height 63, diam. 50 mm.

Length 82, height 57, diam. 37 mm.

China.

QUADRULA 919

Unio fibrosus Hxupr, Conch. Fluy. Nank., II, 1877, pl. x1, fig.

22.

Quadrula fibrosa SIMPSON, Syn., 1900, p. 798.
Unio spuriuws Heupr, Conch. Fluv. Nank., II, 1877, pl. x1,

fig. 23.

I have examined author's specimens of both Unio fibrosus
and spurius and they so unite the figures given by Heude of
the two species that I believe they are both one thing. The
form is more elongated than tientsinensis or sonata, is more
triangular and the beaks are higher than in either.

QUADRULA SAT,APUTIUM von Martens.

“Shell orbicular-subquadrate, heavy, inflated, sculptured
with elevated warts of varied shape, linear, subcircular or
‘ forked over the whole surface; epidermis yellowish-brown, not
shining: rounded before; subtruncate behind; ventral margin
slightly, posterior margin greatly undulated by larger, heavy,
elongated, radiating pustules; beaks obtuse, eroded. Three
cardinal teeth in the right valve, the middle one heavy, trian-
gular, deeply sulcate, the posterior rather ‘smooth, weak,
oblique and the anterior sublinear, small; in the left valve two,
triangular, sulcate, anterior moderately, posterior very heavy ;
lateral teeth quite short, slightly curved, one in the right valve,
transversely striate on both sides like a Castalia; in the left
valve two, parallel. the upper one the smaller, transversely
striate on the inner face, the lower swollen posteriorly, trans-
versely striate on the upper face; sinulus none. Nacre yellow-
ish-white, scarcely pearly ; impressions of the anterior adduc-
tors very deep; accessory impressions small, oblong.

Length 38, height 33, diam. 20.5 mm. Beaks in 2-5 of the
length.” (von Martens).

Type locality, Thuyen-Quan, Anam.

Ouadrula salaputium von Martens, Nachtr. Deutsch. Mal.

Ges., 1902, p. 132.

“Only a single specimen is before me, so that I can not tell
how largely individual characters, as for instance, the color
of the nacre, are included in the above description. It differs

920 QUADRULA

quite strongly from all the Chinese species figured by Heude;
especially in that the teeth are not so oblique as in the related
forms, such as plumbeus Chemn., polystictus and fibrosus
Heude. The striation of the lateral teeth like Castalia I find
likewise, sometimes stronger, but varying in individual speci-
mens, both in the above named species and in Heude’s figures.
It is remarkable that in all the species collected by Fruhstorfer
in Tonkin, the silky lustre, which is found in so many of the
Chinese species, is absent.”

QUADRULA NODULOSA (Wood).

Shell subtriangular, inflated, solid, beaks full and high, ter-
minal or subterminal ; posterior ridge full, subangular, ending
at the posterior base of the shell in a rounded point; anterior
end cut away and rounded below ; base line somewhat curved ;
outline of dorsal slope a long, almost even, curve; surface
somewhat concentrically ridged and covered with coarse nod-
ules; posterior end with very strong, curved, subnodulous
ridges, which are often divaricate on the posterior ridge; epi-
dermis rough, tawny-brown; hinge plate very wide; pseudo-
cardinals radial, curved, rough and split, laterals with strong,
vertical striz ; anterior muscle scars small, deep; beak cavities
very deep, compressed; nacre straw-colored, thinner and iri-
descent behind.

Length 90, height 69, diam. 45 mm.

China.

Mya nodulosa Woop (in part), Gen. Conch. 1, 1815, p. 106,
pl. xxi1, figs. 1, 2;..Jndex, Test, 1825, ip. 42, plein he. aon.
Index West) Rev... 1856ip:.10) play eso:

OQuadrula nodulosa StMPSON, Syn., 1900, p. 708.

Unio nodulosus SowrerRBy, Conch. Icon., X VI, 1868, pl. LXxX XIII,
hg. 430.

Margarita (Unio) nodulosus Lea, Syn., 1836, p. 16; 1838, p.
TS.

Margaren (Prisodon) nodulosus Lea, Syn., 1852, p. 27: 1870,
p27

OQUADRULA g2I

Castalia nodulosa H. and A. ApAmMs, Gen. Rec. Moll., II, 1857,
p. 509.

Umio grandidens Lema, Pr. Ac. N. Sci. Phila., V, 1862, p. 168;
piece. No Seis Phila. V, 1862; p. 205,-pl. xxx, fig. 274; Obs:,
DX 1863* pn 27, phi-xx kis. 277:

Margaron (Unio) grandidens Lia, Syn., 1870, p. 34.

I have before me two opposite, matched valves of this spe-
cies, the right valve being Lea’s figured type of Unio grandi-
dens, the left one accompanying it and sent as from Hot
Springs, Arkansas, by Dr. Byrd Powell to the Smithsonian
Institution. ‘The valves agree exactly with Wood's figures
and brief description of M/ya nodulosa. his shell certainly
never caine from Arkansas and it has the characters of Heude’s
Unio polystictus in such a degree that [ suspect that the two
run together. It 1s a very heavy shell, much more nodulous
and strongly sculptured than Q. tortwosa, tientsinensis, zonata
or fibrosa.

Wood gives four figures of his Mya nodulosa, the first and
second being a solid, nodulous, Chinese species; the third and
fourth seem to be Unio pictorum. Lamarck used the name
nodulosa for a Unio (An. sans Vert. VI, 1819, p. 78), and
refers to the Encyclopedia Methodique, pl. 248, fig. 19, 1797,
and this figure is no doubt that of Unio pictorum. Wood
seems to have confounded the two.

QUADRULA LIEDTKEI Rolle.

“This magnificent, heavy, massive, nodulously sculptured
species, which is not inferior to the finest North American
species, stands nearest to the Chinese Unio nodulosus Wood,
(grandidens Lea), but differs by the incurving of the anterior
margin immediately under the beaks, where there is a distinct
lunule, which is wanting in the Chinese species. “The cardinal
tooth of the right valve is also less deeply paralleled grooved.
I give four figures of the shell and can well dispense with a
precise description.

Length 138, height 90, diam. 90 mm.” (Rolle).

Type locality, Riviere Claire, Tonkin.

Q22 OUADRULA

Unio (Quadrula) ledtkei Route, Nachr. Deutsch. Mal. Ges.,
1904, p. 25, pl. 3; pl. 4, fig. a—DautTzenBerc and Fiscuer,
Ji. -de‘Conch:, Lligareo5) p21.

Dautzenberg and Fischer, (1. c.), consider this to be only a
variety of nodulosus Wood.

QUADRULA BLAISEI Dautzenberg and H. Fischer.

“Shell oval, elongated, very thick and heavy, greatly inflated
anteriorly and with two diverging carine, the lower of which
soon disappears, while the posterior, decreasing in size towards
the posterior extremity, sharply limits the posterior slope. Sur-
face ornamented with irregular, concentric folds, which to-
wards the summits become more pronounced and are mingled
with irregular tubercles, becoming obsolete, however, poste-
riorly where the shell is compressed and almost smooth. Pos-
terior slope with strong, oblique folds, which undulate the
dorsal margin. Ligament corneus, strong, but slightly prom-
inent. Cardinal plate large and overhanging a deep cavity.
Hinge very thick, in the right valve a single, large, sulcate
cardinal tooth (situated between a deep cardinal pit and the
equally deep impression of the anterior adductor muscle) and
an elongated lateral; in the left valve, two cardinal teeth (the
anterior small, situated between a deep cardinal pit and the
equally deep impression of the anterior adductor, the posterior
strong, sulcate) and two elongated, lamellar laterals. Impres-
sion well marked. Epidermis fibrous, deep olive. Nacre
white, iridescent.

Length 08, height 62, diam. 55 mm.” (D. and F.).

Tvpe locality, Bas Luc-Nam, village of Van-len, Tonkin.
Unio (OQuadrula) blaisei Dau'zeNnerRG and FiscuHer, Jl. de

Conch: LUI, 10905, p2i0./plo way figs ae 2:

“This species is distinguished from U. leat Gray by its
heavier shell, much more inflated in the umbonal region and
by the two, elevated carinz that diverge from the beaks. It
is also related to Ouadrula liedtkei Rolle (Nachtrichtsbl. d. d.
Malak. Ges. 1904, p. 25, pl. 3 and pl. 4, fig. a, a) but this latter
species is more regularly oval, does not have the characteristic
carine of blaisei and appears to us to be only a variety of U.
nodulosus Wood.”

QUADRULA 923

QUADRULA MORELETIANA (Heude).

Shell ovate, very heavy, subcompressed; beaks but slightly
elevated, placed at the upper part of the anterior end, but not
terminal ; anterior end widely and almost evenly rounded; post-
dorsal and basal lines evenly curved; posterior end narrowed
and somewhat rounded; surface with subobsolete, concentric
ridges, covered with scattered, coarse nodules, and having a
few curved, subnodulous ridges on the posterior slope; epi-
dermis brownish-chestnut; pseudocardinals somewhat elon-
gated, slightly curved; laterals with vertical striation; beak
cavities deep, compressed; nacre dirty white.

Length 80, height 55, diam. 40 mm.

River Konang-té-tcheou, China.

Unio moreletianus Hrupr, Conch. Fluv. Nank., VIII, 1883,
eins pi Kees er
Quadrula konangensis SIMPSON, Syn., 1900, p. 799.

The outline of this species is almost exactly egg-shaped, and
the species differs from all allied forms in this character. In
the Synopsis I changed Heude’s name moreletianus to konan-
gensis because the name moreleti had been previously applied
to a Unio by Deshayes. But as the two names differ slightly,
it is probably better that Heude’s name should stand.

QUADRULA PoLysticra (Heude).

Shell somewhat rhomboid in outline, moderately inflated,
solid; beaks high, full, terminal; anterior end cut away slop-
ingly below, rounded where it joins the straight or lightly
curved base; outline of dorsal slope raised to a low angle be-
hind the ligament; posterior ridge well-developed, subangular ;
surface covered with rather close, large tubercles; dorsal slope
with curved, subnodulous ridges; epidermis light brownish,
somewhat silky; pseudocardinals elongated, radial, curved,
more or less split; laterals vertically striate ; beak cavities very
deep; anterior muscle scars small, deep; nacre dirty white,
thinner behind.

Length 82, height 58, diam. 36 mm.

China.

924 QUADRULA

Unio polystictus Hgupr, Conch. Fluv. Nank., II, 1877, pl. xu,

hig. 25.

Quadrula polystictus SIMPSON, Syn., 1900, p. 799.
Unio polysticto-scriptus Heupr, Conch. Fluv. Nank., II, 1877,

pl. x11, fig. 26.

Quadrula polysticto-scriptus SIMPSON, Syn., 1900, p. 799.
Unio scripto-polystictus Heupre, Conch. Fluv. Nank., II, 1877,

pl. Xui; fig. 26:

Unio scripto-polystrictus PayreL, Conch. Sam., III, 1890, p.

107.

Heude remarks that some of the species of this group ap-
parently hybridise and it is quite likely he is correct. The
same remark might be applied to some of the Anodontas of
the woodiana group, on which he has so lavishly bestowed
specific names. I have before me a shell of Unio polysticto-
scriptus from the author, which does not exactly agree with
that form or U. scripto-polystictus. ‘The National Museum
specimen is something like Q. nodulosa, but is more decidedly
rhomboid and more strongly nodulous. Heude’s figures of
his two species slightly recall the Q. leat of Gray. After
further study of these forms I think it best to place them under
polystrictus as synonyms, as it does not seem to me that any
clear specific lines can be established. The species as above
constituted is scarcely, if at all, twisted on its axis.

QUADRULA SIMILARIS Simpson.

Shell subrhomboid, solid, inflated; beaks rather full and
high, subterminal; anterior end rounded, somewhat slopingly
cut away below; base rounded; outline of dorsal slope curved,
raised almost to an angle behind the ligament ; umbonal region
covered with narrow, oblique, corrugated ribs, which run
nearly parallel with the dorsal line; surface generally, except
the extreme anterior end, covered with pustules; dorsal slope
with strong, curved ridges; epidermis brown; pseudocardinals
strong, radial, split up into regular divisions; lateral in the
right valve somewhat double; beak cavities deep, compressed ;
nacre white, thinner behind.

Length 85, height 70, diam. 42 mm.

China.

QUADRULA 925

Unio affints Hrupe, Conch. Fluv. Nank.. I, 1875, pl. 1, figs.

7) 74.

Quadrula similaris SIMPSON, Syn., 1900, p. 799.

In the shell figured by Heude there are strong, corrugated
ridges in the umbonal region running nearly parallel to the
dorsal edge of the shell. The author’s specimen in the Nation-
al Museum collection is somewhat eroded in this region, but
does not seem to have these plications very much developed
and I am not certain that it has been accurately named. It is
close to microsticta, but is rather shorter, less decidedly rhom-
boid and is not so finely sculptured. I am doubtful if the two
are distinct. ‘The valves of this species and microsticta are
scarcely, if at all, twisted.

The name affinis was used long before by Dr. Lea for a

Unio.

QUADRULA MicRosticta (Heude).

Shell subrhombcid, scarcely inflated, inequilateral, solid;
beaks only moderately full and high, placed at some distance
from the anterior end; posterior ridge full, rounded; anterior
end rounded; base line curved, sometimes having a light sinus
in front of the posterior ridge; outline of the dorsal slope
curved, sometimes raised into a low angle behind the liga-
ment ; surface, except the anterior portion, covered with strong
nodules; dorsal slope having heavy, curved, corrugated ridges ;
epidermis dark brown or blackish; pseudocardinals striate
but not much split; laterals short, heavy, vertically striate,
that of the right valve partly double; beak cavities very deep,
compressed; anterior scars partly filled with rough nacre;
nacre white, polished behind.

Length 80, height 63, diam. 34 mim.

China.

Unio microstictus Heupr, Conch. Fluv. Nank., II, 1877, pl. x11,

fig. 24.

Quadrula microstictis StmPSON, Syn., 1900, p. 799.

The epidermis is quite dark, the outline is rather rhomboid,
the inflation is moderate and the ridges on the posterior end
are numerous and strong.

926 QUADRULA

Group of Quadrula rochechouarti.

Shell rhomboid, with a strong posterior ridge, rounded be-
fore, incurved below, and somewhat biangulate on the posterior
base, with very strong folds on posterior slope, which begin
on the posterior ridge as knobs; surface strongly pustulous;
beaks rather well forward, sculpture not seen; epidermis con-
centrically wrinkled, black and rough; pseudocardinals strong,
somewhat radial, rough, striate ; laterals more or less vertically
striate, secondary lateral in right valve well developed; beak
cavities very deep, compressed ; posterior calluses faint.

Animal unknown,

QUADRULA ROCHECHOUARTI (Heude).

Shell subtriangular, solid, scarcely inflated, inequilateral ;
valves scarcely, if at all, twisted ; beaks high and full; posterior
ridge very strong, curved, subangular, ending at the base of
the shell; anterior end evenly rounded; base line decidedly
sinused in front of the posterior ridge; outline of dorsal slope
lightly curved; post-basal part somewhat obliquely truncated ;
surface, except the extreme anterior end, covered with very
strong, often lachrymose or double, tubercles; dorsal slope
sculptured with very strong, curved ridges; epidermis black-
ish, thick, often cracking off; pseudocardinals strong, radial,
radially striate; laterals vertically striate, that of the right
valve partly double; anterior muscle scars partly filled with
roughened nacre; beak cavities enormously deep, compressed ;
nacre dull purplish.

Length 130, height 92, diam. 48 mm.

Province of Kiang-su, China.

Unio rochechouarti Hrupr, Conch. Fluv. Nank., I, 1875, pl. v-

fig. 13.

Quadrula rochechouarti SIMPSON, Syn., 1900, p. 800.

A remarkably strong, rude species, which recalls certain
specimens of our Tritogonia tuberculata. ‘The two specimens
in the National Museum collection are from Heude, and are
more elongated than the figure given by him.

QUADRULA 927

Group of Quadrula triclava.

Shell solid, elongate triangular, obtusely pointed at the pos-
terior base, with a decided posterior ridge, along which runs
a row of ponderous knobs; beaks high and far forward; sur-
face strongly nodulous; posterior slope slightly corrugated ;
epidermis dark chestnut; pseudocardinals heavy, subradial,
radially striate; laterals vertically striate, secondary lateral of
right valve well developed; cavity of the beaks enormously
deep and compressed; a granular callus behind the laterals;
nacre silvery, radially, granularly striate outside the pallial
line.

Animal unknown.

QUADRULA TRICLAVUS (Heude).

Shell long, triangular, solid, scarcely inflated, very inequi-
lateral ; beaks elevated, somewhat compressed ; posterior ridge
high, ending near the base in a blunt point ; anterior end round-
ed and somewhat cut away below; base line nearly straight;
outline of the dorsal slope lightly curved; along the posterior
ridge there is a row of ponderous knobs; the rest of the disk,
except the anterior end, is covered with irregular nodules;
epidermis brownish; pseudocardinals strong, radial, slightly
curved, granularly striate; laterals vertically striate, that in
the right valve somewhat double; beak cavities enormously
deep ; compressed; posterior callosities well developed ; pallial
line remote; nacre white, iridescent behind.

Length 110, height 72, diam. 37 mm.

China.

Unio triclavus Heupr, Conch. Fluv. Nank., II, 1877, pl. x,
fies. 27, DTG.
Ouadrula triclava Stmpson, Syn., 1900, p. 800.

A remarkable Naiad, its most prominent character being a
row of four or five large, elevated knobs running down the
posterior ridge.

Group of Oucdrula bazint.

Shell elongate-trigonal, with a fairly well developed poste-
rior ridge, pointed behind: beaks not high, almost at extreme
front of the shell: surface more or less covered with knobs

928 QQUADRULA

and tubercles, which show a tendency to an arrangement in
curved lines; epidermis chestnut to blackish; hinge strong;
pseudocardinals radial, radiately striate; laterals granular,
showing traces of vertical striation; beak cavities very deep.
compressed ; nacre silvery.

Animal unknown.

QUADRULA BAZINI (Heude).

Shell long ovate, solid, very inequilateral, scarcely inflated ;
beaks only moderately full, or elevated; anterior end rounded;
base and dorsal outlines lightly curved to a point some distance
above the base; posterior ridge elevated; surface more or less
covered with knobs or tubercles that have a tendency to be
arranged in curved, subvertical rows; epidermis light and
dark brown, clouded, shining; pseudocardinals radial, radially
striate; laterals with slight vertical striation, that of the right
valve partly double; beak cavities deep, compressed; pallial
line not very remote; nacre white.

Length 105, height 57, diam. 33 mm.

China.

Unio bazini Heupr, Conch. Fluv. Nank., II, 1877, pl. rx, fig.

20.

Quadrula bazini Simpson, Syn., 1900, p. 800.

Heude’s figure differs considerably from the specimen from
him in the National Museum collection, being much less strong-
ly tuberculate and having the later growth of the shell smooth,
while that in the Museum is noduled throughout. The shell is
more ovate than triclavws and lacks the ponderous knobs on
the posterior ridge.

Group of Quadrula leat.

Shell obovate, obtusely pointed behind; posterior ridge low ;
whole surface generally tuberculate or knobbed, with strong,
radial, curved ridges on the posterior slope; beaks rather low,
the sculpture coarse, irregular, broken bars somewhat doubly
looped and swollen on the posterior ridge, with strong, radiat-
ing ridges behind them; pseudocardinals solid, often com-

QUADRULA 929

pressed in the direction of the axis of the shell; laterals granu-
lar ; beak cavities moderately deep; one or more granular cal-
luses behind the laterals; nacre white or lurid, slightly radially
granular outside the pallial line.

Animal unknown.

QuADRULA LEAI (Gray).

Shell somewhat lengthened, more or less obovate, convex,
rather solid, very inequilateral ; beaks moderately full and high,
their sculpture consisting of strong, slightly doubly-looped
ridges, which are sharply angled behind, and radiating lire
back of the main sculpture ; posterior ridge somewhat elevated
above, fading out below; anterior end narrowed, rounded,
often cut away a little below; base line curved, often quite full
at or behind the center; outline of dorsal slope curved, some-
times raised to an angle behind the ligament; surface more or
less covered with strong, lachrymose pustules; these are often
elongated, and arranged in curved or zigzagged patterns ; epi-
dermis greenish or greenish-brown in the young shell, becom-
ing dark brown in the adult stage, sericeous; pseudocardinals
elongated, when adult nearly parallel with the curved, granu-
lar laterals; beak cavities moderately deep, compressed; an-
terior scars partly filled with rough nacre; nacre white or
straw-colored.

Length tot, height 62, diam. 30 mm.

Length 88, height 47, diam. 29 mm.

Length 75, height 52, diam. 28 mm.

China ; ‘fonkin; Mekong River.

Unio leai Gray, Griff. Cuvier, XII, 1834, p. 600 (index), pl.
XxI, fig. 1—KusteR, Conch. Cab. Unio, 1861, p. 232, pl.
LXXVIl1, fig. 3—?HeEupE, Conch. Fluv. Nank., I, 1875, pl.
iV tie. Tes pls wh

Quadrula leat StMpson, Syn., 1900, p. 801.

Margarita (Unio) leati Lua, Syn., 1836, p. 17; 1838, p. 16.

Margaron (Unio) leau Lea, Syn., 1852, p. 23; 1870, p. 34.

Unio leeai HAN EY, Biv. Shells, 1843, p. 182, pl. xxi, fig. 55.

Unio nodulosus Reeve, Conch. Icon., XVI, 1864, pl. 1x, fig. 32.

930 QUADRULA

This species varies much in outline, occasionally being much
narrowed in front, while often shells are quite high anteriorly.
Some specimens are rather short and others are considerably
lengthened, the latter establishing a connection with Heude’s
Unio lelect.

Var. lelect (Heude).

Shell considerably elongated.

Length 72, height 45 mm.

J,ength of an author’s specimen 80, height 45, diam. 29 mm.
Unto lelecit Heupr, Conch. Fluv. Nank., I, 1875, pl.-tv, fig. 12;

pl. v, fig. 14.

Unio leat var. lelecs Paste, Conch. Sam., III, 1890, p. 157.
Quadrula lea var. leleci SimMpson, Syn., 1900, p. 8oI.
Unio richthofeni von Martens, S. B. Nat. Fr., 1875, p. 3;

Nov. Conch, 1V7-1876, p2156, pl. Cxxxvip digs: 1-3.

The figure of Unio leleci in the Conchyliologie Fluviatile
Nanking does not differ from specimens which Dr. Lea has
in his collection under the name Unio leat Gray. But an
author’s specimen of Unio leleci in the National Museum col-
lection is much elongated, is rather more inflated than typical
leai and has smaller nodules.

Var. truncatula ( Neumayr).

“Shell rather small, low, thick, very inequilateral, somewhat
elliptical, with a sloping basal margin and a broad, obliquely
truncate posterior margin. Dorsal margin curved. Beaks not
very prominent, very little eroded. Surface with strong sculp-
ture, which is heavier posteriorly. The beaks are surrounded
with coarse ridges, towards the basal margin are more rather
irregularly arranged tubercles; posterior slope with coarse.
subparallel ridges, which become straight towards the posterior
margin. Hinge of the right valve with a prominent, stout,
quadrate cardinal tooth ; lateral tooth long, lamelliform, curved.
Muscular impressions feeble. Nacre white. Color of epider-
mis. ?

Length 39.5, height 25, diam. 15 mm.” (Neumayr).

QUADRULA 931

Type locality, either Lake Tai-hu or the King’s Canal,
Province of Kiang-su, China.

Unio leai var. truncatula NeuMAyr, Ergebnisse d. Reise Szech-

eny Ostasien, II, 1898, p. 643, pl. 11, fig. 8.

“This form belongs to what appears to be a widespread type
in China characterized by its rather remarkable sculpture.
To it belong Unio affinis Heude, scriptus Heude, leat Heude,
montanus Heude, Jeleci Heude; the last two mentioned forms
should, as it appears, be referred to the very variable Unio
leai Gray as varieties and to this group, doubtless, belongs
the form here described; but it differs from all of the other
varieties by its small size, elongate form, straight basal margin
and obliquely truncate, pointed posterior end; in spite of these
clear differences, I believe that at present it should only be
considered as a variety, but a sure decision can only be reached
with more material. One, probably full grown, example only.”

Var. ponderosa Dautzenberg and H. Fischer.

“Form very thick, greatly inflated, very inequilateral, beaks
terminal, with a strong carina extending from the beaks and
bounding the posterior slope, which is ornamented with large,
oblique, regularly spaced folds. Ventral margin curved and
sharply bent upwards posteriorly ; the ligament appears to be
constantly shorter than in typical leat. U. leleci Heude,
(Conch. fluv. pl. 1v, fig. 12), appears to be a connecting link
between the type and our var. ponderosa, while the shell fig-
ured by -Heude, (pl. v, fig. 14), appears to us to be almost
identical with typical Jeai.” (D. and H. F.).

Unio (Quadrula) leat var. ponderosa DAuTZENBERG and H.

Fiscuer, Jl. de Conch., LIII, 1905, p. 200.

QUADRULA GOTTSCHEI (von Martens).

“Shell oblong-elliptical, compressed, epidermis somewhat
silky, brown (reddish-yellow in the young), shortly and rather
narrowly rounded in front, expanded posteriorly and sculp-
tured in the middle with wart-like tubercles, which become
elongated and radially divergent towards the margin, obsoles-
cent in the adults; posterior dorsal margin quite curved, the

932 QUADRUL,A

hinder end an obtuse, subdeflexed, truncated rostrum ; ventral
margin in the young decidedly curved, in the adults scarcely at
all. Beaks somewhat swollen, eroded. Nacre white, reddish-
yellow in the centre. Cardinal teeth almost horizontal, sub-
parallel, two in the left valve; the anterior delicate, smooth,
the posterior heavier, subtrigonal, longitudinally sulcate; one .
in the right valve stout, rugose; lateral teeth slightly curved,
rather smooth, elongate, two in the left valve, the lower sub-
duplicated posteriorly : one in the right valve. Anterior mus-
cular impressions longitudinally oblong, rugose; pallial line
often transversely striate.

Specimen maximum, long. 120, alt. ad vertices 45, posterior
65, diam. 36 mm.

Specimen medium, long. 82, alt. ad vertices 35, posterior 46,
diam, 25 mm.

Beaks situated at one-fifth of the length; ligament extended
to three-fifths of the length.” (von Martens).

Type localitv, Soeul, Amnokgang near Wiwon and Puk-
chang, Korea.
Unio gottschei von Martens, S. B. Nat. Fr., 1894, p. 215.—

SIMPSON, Syn., 1900, p. 862.
Unio (Ouadrula) gottschei von Martens, Zool. Jahrb. Suppl.,

WL O05) P45, ple oe

“Groups with the Chinese U. leai Gray and, young, scarcely
distinguishable, but the anterior end of our species is not so
broadly rounded as in U/. leai, the length of the shell in pro-
portion to its height is greater, the sculpture is weaker and is
more closely drawn together in tuberculous ridges, there
being few isolated warts. I know of no similar species from
Japan-”

QuapruLtA MANsuyI Dautzenberg and H. Fischer.

“Shell very thick and heavy, elongate trapezoidal, rounded
in front, angulated behind, surface with irregular lines of
growth and in the centre of the disk some radiating, subverti-
cal, more or less confluent, folds, which on the posterior slope
become much stronger, slightly nodulous and divergent; an-

QUADRULA 933

terior part of the disk without folds. Beaks approximate,
eroded, a little in front of the anterior one-third of the length.
Interior of the valves nacreous, shining, somewhat covered
with microscopic granulations. Hinge very heavy; in the
right valve two sulcate cardinals, of which the anterior is the
larger and more projecting, and a single lateral, strong, ele-
vated, angulated above and separated from the dorsal margin
by a wide, deeply grooved space; in the left valve, two sulcate
cardinals, of which the posterior is the larger and two lamellar
laterals, separated from each other by a deep groove and from
the margin of the shell by a rather large, deeply excavated
space. Cicatrices of the adductor muscles small, rounded, well
marked. Pallial impression entire, ascending anteriorly, where
it separates gradually from the margin of the shell. Edge of
the shell simple, sharp. Epidermis deep brownish-yellow,
slightly fibrous towards the margin. Nacre white, not bril-
liant and scarcely iridescent.
Length 100, height 64, diam. 37 mm.” (D. and F.).

Type locality, Song Bang-Giang a Cao-Bang, Indo-China.
Unio (Quadrula) mansuyi DautzENBERG and H. Fiscuer, Jl.
de Conch., LVI, 1908, p. 214, pl. VIII, fig. 5 and text-fig.

“This species differs from U. leai by its posterior region
obliquely truncate and acuminate at the post-basal extremity ;
its sculpture is also different, consisting of folds subvertical in
the centre of the disk and sharply diverging on the posterior
slope; there are no isolated tubercles as in that species.”

QuADRULA OVATA Simpson.

Shell rather small, irregularly ovate, solid, inequilateral, in-
flated; beaks apparently not very full or high; posterior ridge
somewhat double, ending behind in a wide, nearly square bi-
angulation: anterior end rounded; base lightly curved, outline
of dorsal slope straight in front, curved behind; beaks corru-
gated; carina spinose; epidermis greenish-black or chestnut,
faintly rayed; pseudocardinals short, solid; nacre flesh-color,
maculate with white.

Length 45, height 28, diam. 20 mm.

River Ning-Konofou, China.

934 QUADRULA

Unio vestitus var. a Heupr, Conch. Fluv. Nank., VIII, 1883,
pl Lyin, figs E12:

Quadrula ovata SIMPSON, Syn., 1900, p. 801.

Acuticosta ovata Haas, Conch. Cab. Unio, 1912, pl. 30, figs.

8 and Io.

Parren'sia hunanensis Haas, Nachr. D. Mal. Ges., 1910, p. 97;

Conch. Cab. Unio, 1912, pl. 30, fig. 9.

I have never seen this shell, which does not seem from the
figure to be a variety of Unio westitus as Heude believes. The
specimen from which it was taken was considerably eroded
and the species may not group here at all. The teeth as figured
-are much like those of cornuam-iune.

Haas, (1. c. 1912), considers his hunanensis a synonym of
this species.

QUADRULA CAVEATA (Heude.

Shell slightly obovate, subrhomboid, convex to subinflated,
solid, inequilateral; beaks apparently not high nor very full;
anterior end somewhat narrowed and rounded; dorsal and
basal outlines lightly curved ; posterior end somewhat obliquely
truncate above; surface with irregular, strong ridges that fol-
low the growth lines and often having a few nodules; epider-
mis chestnut to blackish; pseudocardinals rather small, almost
parallel with the curved laterals; laterals slightly vertically
striate, that of the right valve somewhat double; nacre dirty
whitish.

Length 89, height 55 mm.

Length 85, height 50, diam. 30 mm.

China.

Unio caveatus HEupE, Conch. Fluv. Nank., III, 1877, pl. xxrv,

fig. 53.

Quadrula caveata SIMPSON, Syn., 1900, p. 801.
Unio contritus Heupr, Conch. Fluv. Nank., VII, 1881, pl. Lv1,

fig. 103.
Unio quadrangulosus Hreunr, Conch. Fluv. Nank., VII, 1881,

pl. ivi, fig. 104.

I have united under the oldest name three of Heude’s forms,
which do not seem to me to be separable. The Unio caveatus

QUADRULA 939

is a rudely sculptured form; the other two are smoother.
The species is heavier than the forms I have united under
cornuum-lune, and are rather more elongated and differently
sculptured.

QUADRULA CORNUUM-LUN@ (Heude).

Shell irregularly elliptical with a tendency to become some-
what rhomboid, subsolid to moderately solid, scarcely inflated ;
beaks not high or full; posterior ridge low, rounded, some-
times slightly biangulate; anterior end rounded; basal and
dorsal lines lightly curved; posterior end somewhat obliquely
subtruncate above, rounded or biangulate below; surface, ex-
cept the anterior end, covered with elongated pustules, which
are sometimes developed into radial ridges; epidermis brown
or blackish; pseudocardinals rather small; laterals granular,
scarcely vertically striate; beak cavities only moderately deep ;
nacre dirty white or purplish.

Length 52, height 38, diam. 22 mm.

China.

Unio montanus Heupe, Conch. Fluv. Nank., I, 1875, pl. iv.
fig.
Unio cornuum-lune Hrupr, Conch. Fluv. Nank., VIII, 1883,

pl. tvil, fig. 105.

Quadrula cornvuum-lune Simpson, Syn., 1900, p. 802.
Unio paschalis Hrupre, Conch. Fluv. Nank., VIII, 1883, pl.

EVV, os, 110:

Unio verruculosus Hrunr, Conch. Fluv. Nank., VIII, 1883, pi.

EVirE, is. TIT.

Unio abortivus Heupvr, Conch. Fluv. Nank., VIII, 1883, pl.

UXT, eer ne
Unio monticcla Hrupr, Jl. de Conch., XXXII, 1884, p. 10.

In the Synopsis the name Unio trisulcatus Heude was by
oversight made a synonym of cornuum-line. It has a very
different shell indeed. Heude changed the name montanus,
proposed in 1875 for the above species, to monticola in 1884
because the former had been used for a Unio previously. His
name, cornuum-lune, proposed in 1883 for what I believe is

936 QUADRULA

the same species, will have to stand if my idea as to the identity
of these forms is correct. The shell is shorter than Jeai, not
narrowed in front and is not so inflated. This species and
some of the others of this group approach some of the forms
of the Unio japanensis, but on the whole they have heavier and
ruder shells than that form has and the beak cavities are
deeper. I therefore am inclined to believe that they are elon-
gated Quadrulas.

Var. cinnamomea (Gredler).

Shell almost regularly elliptical or very slightly ovate;
beaks not at all prominent; surface, except the anterior end,
covered with fine, radiating somewhat broken corrugations,
having a few pustules in front.

Hunan, China:

Unio leai var. cinnamomeus GREDLER, Jahrb. Deuts. Mal. Ges.,

VIIL, 1889, p. 122, pliavi, foie: ;
Ouadrula cornuum-lune var. cinnamomeus SIMPSON, Syn.,

1900, p. 802.

This form was made a variety of Jeai by Gredler, but I am
inclined to believe it to be nearer cornuum-lune. Gredler does
not give the dimensions.

QuADRULA SCRIPTA (Heude).

Shell irregularly long elliptical, inflated, solid, inequilateral ;
beaks moderately full and elevated; posterior ridge well de-
veloped, subangular above, ending in a point about on the
median line; surface having strong, wide, uneven, concentric
ridges, which are separated by narrow grooves, and on these
ridges irregular knobs, tubercles and subradial ridges ; pseudo-
cardinals somewhat triangular, split up radially ; laterals with
faint, vertical striation; beak cavities somewhat deep.

Length 73, height 51, diam. 39 mim.

China.

Unio scriptus Heupr, Conch. Fluv. Nank., I, 1875, pl. 11, figs.

8, 8a.

OQuadrula scripta Simpson, Syn., 1900, p. 802.

QUADRULA 937

This is a robust, solid, quite inflated form, which has some
of the characters of the nodulosa group. The form however is
much like that of QO. cornuum-lune.

QUADRULA DIVERGENS (Benson).
Unio divergens Benson, Jl. As. Soc. Beng., XXIX, 1855, p.

ig.

Quadrula divergens SIMPSON, Syn., 1900, p. 802.

Unio divergens Benson, from Chusan Island, China, has
never been figured, so far as I know. It probably groups
here and may be a form of Q. leai. The description is not now
accessible to me.

Subgenus Discomya Simpson, 1900.

Discomya SIMPSON, Syn., 1900, p. 802.

Shell subsolid, round obovate or subrhomboid, lenticular,
rather compressed, widely, faintly biangulate behind, with
scarcely any vestige of a posterior ridge; beaks very low,
sculpture not seen; front half of the shell densely covered with
fine pustules arranged in curved rows in two directions as if
engine-chased, over which the epidermis is wrinkled. The
hinder half is covered with fine, radiating and undulating
corrugations, curved upward posteriorly, which are slightly
nodulous and show through on the inside of the shell; one
slightly compressed pseudocardinal in the right valve and two
in the left; one delicate, curved lateral in the right valve and
two in the left; beak cavities deep, compressed; nacre lurid;
pallial line showing a slight posterior sinus.

Type, Unio radulosus Drouet and Chaper.

QUADRUILA RADULOSA (Drouet and Chaper).

Shell obovate with a tendency towards being subrhomboid,
convex, subsolid, inequilateral, lenticular; beaks apparently
not full or elevated; anterior end rounded or sometimes. a little
truncate and angled above; base line lightly curved ; dorsal line
behind the beaks elevated almost into a wing, the hinder part
of the wing and dorsal slope obliquely truncated; posterior

938 QUADRULA

ridge scarcely developed above, sometimes feebly and widely
double below and ending in a wide, ill-defined biangulation ;
surface throughout in front of the posterior ridge densely
covered with pustules, looking as if engine-chased, rarely in
somewhat chevron-shaped patterns; behind the front part of
the posterior ridge is a series of fine, curved, subradial ridges ;
epidermis wrinkled, scarcely shining, various shades of brown.
or brown and green; pseudocardinals small, radially striate;
laterals rather delicate, curved; beak cavities moderately deep,
compressed; muscle scars not deep; nacre lurid brownish,
thinner behind where the pattern of sculpture shows through..

Length 58, height 45, diam. 20 mm.

Borneo.

Unio radulosus Drourt and CHAprgEr, Mem. Soc. Zool. Fr., V,
18Q2, p.. E50, pl. Vv, hes.,00-12:

OQuadrula radulcsa StMPSON, Syn., 1900, p.°803.

Discomya radulosa Haas, Con. Cab. Unio, 1910, pl. xvi, figs.
T-2.
A decidedly interesting and unique shell. In many cases the

sculpture in front of the posterior ridge is almost as perfect

and regular as though it had been turned out by machinery.

The lenticular form the curiously varigated epidermis, the
visibility of the sculpture through the posterior nacre are
striking characters. Although I cannot be certain as to the
systematic position of this form, yet I believe that it is rather
closely related to the heavy Chinese forms that I have placed
in Quadrula and probably most near to the group of Q. leat.
Var. rhomboidea Simpson.

Shell longer than the type, rhomboid, the posterior ridge
widely double, ending at and near the base in a wide biangula-
tion ; base line incurved behind ; nacre lurid, dark purplish lead-
color.

Length 57, height 37, diam. 22 min.

Selrocany, Borneo.

Ouadrula radulosa var. rhomboidea SIMPSON, Syn., 1900, p-
803.

SCUISTODESM US 939

I have seen only a single shell of this form (No. 126472 of
the U. S. Nat. Museum) and it is so different from radulosa
that if I were positive that it was normal I would give it
specific rank. It is badly eroded, but is very differently shaped,
has much less strongly marked sculpture and is more tawny
than typical shells. With it is a normal younger specimen of
radulosa from the same locality.

Genus SCHISTODESMUS Simpson, 1goo.

Shistodesmus SIMPSON, Syn., 1900, p. 803.

Shell rather solid, triangular, inflated, truncate above in
front, somewhat swollen just behind the center of the base,
pointed behind; beaks high; beak sculpture not seen; surface
thrown up into strong, very wide, concentric ridges, one or two
with each season’s growth, and pinched up in the central part
to form a radiate row of compressed knobs or spines; epi-
dermis shining, greenish-yellow or brownish, having mar-
velously delicate, concentric, microscopic lire, often painted
with a few elegant, broken, green rays; there is one large,
high, triangular pseudocardinal in the left valve under the
beak, a deep, triangular pit in front of it, with an erect, radial
lamellar tooth in its center and a high, lamellar, curved tooth
in front of the pit, parallel with the edge of the shell connected
with the central tooth. A heavy triangular bifid or trifid pseu-
docardinal in the right valve stands close to the anterior edge
of the shell and is separated from it by a deep, compressed
pit ; behind this tooth, deep down at its base, is a narrow shelf,
and back of this the entire hinge plate is cut out in a deep
sinus to the beak; two laterals in each valve; cavity of the
beak in left valve deep, somewhat compressed; in the right
entirely opened by the sinus; muscle scars small, deep, smooth :
pallial line with a sinus at its posterior end; a beautiful, gran-
ularly striate callus is developed behind the laterals; nacre
finely, often bifurcately, radiate striate outside the pallial line.

Animal unknown.

Type, Unio lamprevanus Baird and Adams.

940 SCHISTODESMUS

SCHISTODESMUS LAMPREYANUS (Baird and Adams).

Shell triangular ovate, solid, subinflated to inflated, inequi-
lateral; beaks moderately full and high; anterior end slightly,
obliquely truncate above, rounded below; base rounded; out-
line of dorsal slope lightly curved or straight; posterior ridge
low, placed close to the post-dorsal edge of the shell, ending
behind in a point about on the median line; surface having a
series of strong, concentric ridges, which fade out just in
front of the posterior ridge as in Venus paphia, each ridge is
elevated into an elongated knob about the middle of the disk ;
epidermis shining, apparently smooth but under a strong glass
it is seen to be beautifully concentrically striate, yellowish-
green or greenish-yellow with a few, elegant, broken, green
rays, the old shells becoming brownish; pseudocardinals ele-
vated, ragged; left valve with one high one under the beak;
there is a compressed anterior tooth in front of this, close to
the edge of the shell that connects with it and between them
there is a deep pit filled with ragged matter; right valve with
a somewhat double pseudocardinal in front of the beak; be-
hind this there is a depressed shelf, and behind the shelf, under
the beak the hinge plate is entirely cut off; laterals granular,
that of the right valve partly dowble; beak cavities of the left
valve deep; that of the right made shallow by the hiatus of
the hinge plate; muscle scars small, impressed; callus behind
the laterals small and distinct; nacre white, iridescent behind.

Length 45, height 38, diam. 20 mm.

Length 40, height 38, diam. 24 mm.

Length 57, height 37, diam. 28 mm.

China.

Unio (Dysnomia) lampreyanus Barro and Apams, Proc. Zool.
Soc. Lond., 1867, p. 491, pl. xxv1, figs. 2, 2a.—SOWERBY,
Conch. jicon., XVI, 1868, pl. Lxxxvir, fig. 469—HeEuDE,
Conch. Fluv. Nank., VII, 1883, pl. trx, figs. 114a, 114D.

Margaren (Unio) lampreyvanus Lea, Syn., 1870, p. 30.

Shistodesmus lampreyanus SIMPSON, Syn., 1900, p. 804.

Schistodesmus iampreyanus Haas, Conch. Cab., Unio, 1912,
pl. 31, figs. 1-4, 6.

GIBBOSULA 941

Three shells of this remarkable form are before me and
they vary a good deal in dimensions, but agree very well in
the essential characters. ‘The one whose measurements are
first given is probably hardly adult and is elegantly painted ;
the other two are older and not so bright. I know nothing
whatever of the anatomy of this species and it is only placed
near Quadrula provisionally. Its form and the deep beak
cavities would seem to ally it to that genus.

SCHISTODESMUS SPINOSUS Simpson.

Shell somewhat triangular, inequilateral, subinflated or in-
flated, moderately solid; beaks rather full and high; posterior
ridge apparently well developed, angular, ending in a blunt
point not far above the base of the shell; anterior end obliquely
truncate above, rounded below; base line rounded; outline
of dorsal slope curved; surface apparently sculptured with a
few, widely spaced, concentric furrows, having wide, flat
ridges between them, having on the posterior ridge one or
more, well-developed, short spines; epidermis probably bright,
with narrow, scattered, broken rays; right valve having the
hinge plate cut off at the beak, its lateral somewhat double.

Length 35, height 30, diam. 20 mm.

China.

Unio vestitus HeupDE, var. B, Conch. Fluv. Nank., VIII, 1883,

PLL foe TDS.

Shistodesmus spinosus SIMPSON, Syn., 1900, p. 804.
Schistodesmus spmosus Haas, Conch. Cab., Unio, 1912, pl. 31,

fig. 5.

Heude makes this a variety of his Unio vestitus, but it seems
to me to be totally different and closely related to, if not a
variety of, lampreyanus. He gives no separate description, so
I am in the dark regarding several important characters. The
ridges are wider than in lampreyanus and the latter has no
spines.

Genus GIBBOSULA Simpson, 1900.

Gibbosula SIMPSON, Syn., 1900, p. 804.
Shell very solid, inequilateral, triangular, elliptical, arcuate,
pointed behind, with a low, well-marked posterior ridge; beaks

942 GIBBOSULA

rather high; beak sculpture not seen; posterior two-thirds of
the shell covered with somewhat radiating corrugations and
nodules; posterior slope having strong, subradial folds; epi-
dermis dark ; hinge plate very wide; pseudocardinals not large,
stumpy, rough; laterals very heavy, club shaped; beak cavities
enormously deep and compressed; anterior cicatrices rather
shallow, rough in the bottom; posterior cicatrices deep and
distinct; a strong rib runs from the front part of the beak
cavity toward the posterior base; nacre whitish.

Animal unknown.

Type, Mya crassa Wood.

GIBBOSULA CRASSA (Wood).

Shell somewhat elongated, convex, subtriangular, inequi-
lateral, ponderous; beaks rather low, but the umbonal region
elevated; posterior ridge well developed, narrowly rounded,
not so full as the region in front of it; anterior end rounded ;
base nearly or quite straight; outline of dorsal slope curved,
ending behind in a point at the termination of the posterior
ridge, the region between this and the base obliquely subtrun-
cated; surface with rude, concentric growth lines; the hinder
three-fifths of the shell covered with broken, subradial ridges,
which are divaricate just in front of the posterior ridge; epi-
dermis brown; hinge very heavy, the plate flattened ; pseudo-
cardinals low, somewhat ragged; laterals remote, short, solid,
that of the right valve partly double; muscle scars deep; beak
cavities very deep, compressed; nacre white or flesh-colored,
thick in front with an oblique rib running downward and for-
ward from the pseudocardinals, an oblique furrow near the
laterals, and having numerous small scars, by which the mantle
is attached to it.

Length t10, height 71, diam. 40 mm.

China.

Mya crassa Woop, Gen. Conch., 1815; p. 106, pls.) xx, xxi;
Ind. Test., 1825, p. 12, pl. 11, fig. 28b ; Ind. Test. Rev., 1856,
Ds 10.) ple nie es 28.

Gibbosula crassa StMPSON, Syn.. 1900, p. 804.

Mya ponderosa.Dituwyn, Dill. Cat., I, 1817, p. 5.

CUNEOPSIS 943

Margarita (Unio) ponderosus Lea, Syn., 1836, p. 14; 1838, p.

14.

Unio ponderosus Hanyey, Test. Moll., 1842, p. 177.
Margaron (Unio) ponderosus Les, Syn., 1852, p. 21; 1870, p.

22:

A remarkable Naiad of whose systematic position I cannot
be certain. Its general form is something like that of a very
heavy Afargaritana and the numerous small pits by which in
life the mantle is attached to the nacre carry out this resem-
blance. But the shell is exceedingly ponderous, the hinge plate
is wide and flat, the teeth are well developed and Ouadrula-like,
as are the very deep, compressed beak cavities. The oblique
rib and furrow in the cavity of the shell recall Unio gibbosus
or some of the Ptychobranchi.

Genus CUNEOPSIS Simpson, 1900.

Cuneopsis SIMPSON, Syn., 1900, p. 804.

Shell solid, elongated, wide and truncate or rounded in front,
tapering to a point behind; often twisted on its axis and curved
to the right or left; beaks rather high, anterior; beak sculp-
ture apparently a few coarse, subparallel, nodular ridges curved
up behind; posterior ridge low, close to the hinge line and in
front of it the shell is full; surface slightly, irregularly, con-
centrically striate; epidermis dark, having a peculiar, dull,
silky luster; hinge rather narrow; pseudocardinals two in the
left valve immediately under the beak, the anterior com-
pressed, high and nearly parallel with the outer edge of the
shell, the posterior heavy, joined to the anterior above, with
a deep, triangular cavity between; right valve with one large,
triangular, anterior pseudocardinal with a deep, triangular pit
back of it, and often a small, low, compressed tooth behind the
pit; laterals granularly striate; beak cavities rather deep; an-
terior muscle scars deep, rough at the bottom; posterior scars
large, long and oblique; nacre silvery, sometimes radially
striate at the edge; pallial line indented into a sinus at its
posterior end, above which is a granular, striate callus.

Animal unknown.

Type, Unio celtiformis Heude.

944 CUNEOPSIS

The species, which I have placed in Cuneopsis, though vary-
ing considerably in details are all evidently closely related and
form a natural group. This group is characterized by having
elongated, intlated shells with unicolored, silky, brownish ept-
dermis, two, more or less connected, pseudocardinals in the
left valve with a deep pit between them, one in the right valve
with a deep pit behind it, very deep beak cavities, and elongat-
ed, oblique posterior muscle scars. Owing to our almost
total ignorance of the anatomy of most of the Oriental Natades
much of the classification I have offered is only tentative. I
have endeavored to do the best I could from the shell char-
acters, but in most cases the beak sculpture is completely
eroded away, and for some of the species I have only seen
figures or descriptions, which do not cover some of the most
important points.

Key to species of CUNEoPSIS.

Shell more or less obliquely truncate above posteriorly.

Strongly curved and twisted. pisciculus.
Not curved or twisted. rufescens.
Shell. not obliquely truncated, pointed behind at the median
line.
Distinctly swollen in front. ~ capitata.
Scarcely swollen in front, inequivalve. celtiformis.
Subtruncate above the posterior ridge, drawn out to a long
point behind. heudet.
Truncate anteriorly. tauriformis.

CUNEOPSIS CAPITATA (Heude).

Shell wedge-shaped, long triangular, inequilateral, solid,
rounded and infiated a short distance in front, becoming sud-
denly contracted behind the inflation; beaks high, full, placed
close to the anterior end; anterior end rounded ; anterior part of
the base rounded; behind the anterior inflation there is a sinus;
outline of dorsal slope nearly straight, the shell ending behind
in a point; surface with low ridges, which follow the growth
lines; epidermis brownish, silky; left valve with an anterior,

CUNEOPSIS 945

compressed pseudocardinal running parallel with the edge
of the shell and an elevated, triangular, striate posterior one,
with two straight laterals; right valve with a strong, elevated
anterior pseudocardinal and a vestigial posterior one, and a
somewhat double lateral, the pseudocardinals fitting into deep
cavities in the hinge; muscle scars deep, the posterior ones
oblique and elongated; beak cavities very deep, compressed ;
nacre white, thinner behind.

Length 86, height 44, diam. 31 mm.

China.

Unio capitatus Hrupr, Jl. de Conch., XXII, 1874, p. 114;

Conch. -Eliuy. Nank., 1.1875, pl. 11, fig. s.

Cuneapsis capitatus SIMPSON, Syn., 1900, p. 805.

A remarkable shell, which is wedge-shaped whether viewed
from the side or above. The anterior end is suddenly thick-
ened and this part of the shell is much solider than the poste-
rior part. In both of the specimens in the National Museum
the hinder end is flexed to the left, that of the larger shell
being decidedly so. ‘The two pseudocardinals are remarkably
large and elevated, and are striate. The National Museum
has fossil specimens of this species, which are considerably
larger than the above measurements or those given by Heude.

CUNEOPSIS HEUDEI (Heude).

Shell elongate, ovate, inflated, solid, inequilateral; beaks
rather high and full, their sculpture appearing to consist of
strong, irregular ridges, which curve up decidedly behind;
posterior ridge rather low, but pinched up into a sharp angle,
nearly straight and close to the dorsal part of the shell, which
is somewhat truncated; anterior end rounded; base line lightly
curved, ending in a point about on the median line; surface
with low, rather fine ridges, which follow the growth lines,
sometimes having a few, faint, subradial ridges on the disk ;
epidermis dark brown, silky; left valve with an anterior com-
pressed pseudocardinal and a triangular, elevated posterior
one, with two straight laterals; right valve with a high pseudo-
cardinal and one lateral; the pseudocardinals and sockets rag-

946 CUNEOPSIS

ged; muscle scars deep, the posterior ones oblique and elon-
gated ; beak cavities deep, compressed ; nacre white.
Length 70, height 33, diam. 24 mm.
China.
Unio heudei Arupe (Bazin manuscript), Jl. de Conch., XXII,
1874, p. 114.
Cuneopsis heudei Stmpson, Syn., 1900, p. 805.
Unio corderii Heupr, Conch.,-Fluv. Nank., I, 1875, pl. 1, fig. 3.
This species bears a strong superficial resemblance to the
Unio pazi lea, but is much solider and has deeper beak cavi-
ties and totally different teeth. The beak sculpture, which is
somewhat eroded in the specimens examined, seems most like
that of the Pleurobemas. The National Museum specimens
gape slightly behind, but are not bent to the right or left.

CUNEOPSIS CELTIFORMIS (Heude).

Shell much elongated, slightly inequivalve, inequilateral,
solid, wedge-shaped, inflated; beaks full and elevated in old
shells; posterior ridge low, rounded, close to the dorsal line;
anterior end rounded; base line nearly or quite straight, some-
times rather full towards the posterior end; dorsal line straight
or lightly curved; the hinder end of the shell pointed; surface
with numerous, low, concentric ridges; epidermis light green-
ish brown in the young state, dark brown when old, silky ;
left valve with a compressed anterior pseudocardinal, which
is more or less united to an elongated, triangular posterior one,
and below and between them there is a deep socket; right valve
with one elevated, rather solid, pseudocardinal, pseudocardinals
recurved; laterals two in the left valve and one in the right;
anterior scars large, deep and rough; posterior scars oblique,
impressed ; beak cavities very deep, compressed; nacre white,
thinner behind.

Length 117, height 38, diam. 31 mm.

China.

Unio celtiformis Hrupx, Jl. de Conch., XXII, 1874, p. 113;

Conch., Fluv., Nank., I, 1875, pl. 1, fig. 4.

Cuneopsis celtiformis Stmeson, Syn., 1900, p. 805.

CUNEOPSIS 947

Old specimens of this species show a little of the sudden
swelling forward that is seen so strikingly in capitata. The
shell is slightly inequivalve, the left valve, in the examples
seen, being pushed down so that the right is higher. One of
the specimens which I have examined has the posterior end
very lightly turned to the left.

CUNEOPSIS PIscIcuLUs (Heude).

Shell elongated, solid, inequilateral, slightly inequivalve,
twisted and very strongly turned to the right behind; beaks
full, high, elongated; posterior ridge well developed, placed
near the dorsal line, narrowly rounded, or somewhat angular
above, ending behind in a point midway between the base and
dorsum ; anterior end rounded; base line nearly straight; dor-
sal outline curved a little; surface nearly smooth or with slight-
ly elevated growth lines; epidermis greenish-brown when
young, almost blackish when old, silky; left valve with two
elevated pseudocardinals, the anterior somewhat spur-like, the
hinder long triangular, with a pit between them, and two lat-
erals, the upper small; right valve with one elevated pseudo-
cardinal, a vestigial one behind it and a deep pit between, with
a strong, faintly vertically striate lateral; anterior scars deep;
posterior scars oblique; beak cavities very deep, compressed ;
nacre white, silvery, iridescent behind ; pallial line widely trun-
cate behind, the space outside of it radially striate.

Length 123, height 49, diam. 30 mm.

China.

Unio pisciculus Heupe, Jl. de Conch., XXII, 1874, p. 115;
Conch. Fluv. Nank., I, 1875, pl. m, figs. 6, 6a.

Cuneopsis pisciculus SIMPSON, Syn., 1900, p. 805.

Unio retortus von Martens, Sitz. Ber. Ges. Nat. Fr., 1875,
p. 4; Nov. Conch., IV, 1876, p. 158, pl. cxxxv1, figs. 3, 4.
This species is so contorted that it can scarcely be measured.

In this character it is like Arconaia, but there is no vestige of

an anterior wing, the pseudocardinals are constructed on a

totally different plan and the beak cavities are deep, a char-

acter common to all the forms I have placed in Cuneopsis,

948 CUNEOPSIS

while in both the species of Arconaia they are remarkably
shallow: in fact they have no beak cavities at all. The elon-
gation of the shells of these forms, their dark, silky, unicol-
ored epidermis, the oblique, elongated posterior muscle scars
and the hint at a pallial sinus in some of them and the tortion
of the shell are characters common to Arconaia. In this spe-
cies the nacre outside the pallial line is decidedly granularly
radiate striate and there are indications of the peculiar nacre-
ous calluses behind the laterals, characters seen to some ex-
tent in other species of the group, in some specimens of Ar-
conaia and many of the forms I have placed in Quadrula.

CUNEOPSIS RUFESCENS .(Heude).

Shell long rhombic, subsolid, inflated, inequilateral; beaks
full and high; posterior ridge well developed, narrowly round-
ed, ending in a point near the base of the shell; above it there
is a shallow, radial depression; anterior end rounded; basal
and dorsal lines nearly straight and subparallel; posterior end
obliquely truncated above; surface nearly smooth, covered
with a greenish-brown, silky epidermis; left valve with two
high, compressed pseudocardinals, which are partly united, the
hinder being slightly triangular, with a deep pit below and
between them; left valve with one pseudocardinal; laterals
two in the left valve and one in the right ; anterior scarsdeep ;
posterior scars shallow, slightly oblique; beak cavities deep ;
nacre warm flesh-color, lighter colored at the edge, thinner and
iridescent behind; pallial line with a shallow sinus behind.

Length 70, height 28, diam. 24 mm.

Province of Kiang-Si, China.

Unio rufescens Heupr, Jl. de Conch., XXII, 1874, p. 113;

Conch. Fluv. Nank., I, 1875, pla, fig. 2:

Cuneopsis rufescens Simpson, Syn., 1900, p. 805.

The beak sculpture is partly visible in one of the valves of
a specimen in the National Museum collection and the poste-
rior part of it consists of fine, radiating lirze, such as is seen
in some of the North American Uniones. This species may
at once be distinguished from the other members of the group
by its obliquely and decidedly truncate posterior end.

NODULARIA 949

CUNEOPSIS TAURIFORMIS Preston.

“Shell obliquely ovate, truncate anteriorly, wedge-shaped
posteriorly, solid. periostracum dark, having a silky lustre, ex-
terior umbonal region with raised zigzag ridges, concentric
striz below, the umbones turned slightly inwards, decorticated ;
two cardinal teeth in the left valve, the anterior rather thin,
the posterior thick with a deep triangular pit between; right
valve with one thick cardinal tooth situated below the umbo,
lateral teeth long and roughly striated; nacre silvery; a deep
pit marks the place of the anterior adductor, the posterior
scar being only moderately indented.

Length 31, height 20, diam. 16.5 mm.” (Preston).

Type locality, Yunnan-fu, Yunnan.

Unio (Cuneopsis) tauriformis Preston, Ann. Mag. Nat. Hist.,

£7), 2c NV LE, 1906,. p..246, pl. 1x; fig’ 9.

“T have been unable to find any species closely allied to this,
which I take to belong to the genus Cuneopsis Simpson.”

Subfamily HYRIANA® Swainson.

(ENDOBRANCHL®. )

Male and female shells alike, with beak sculpture radial or
zigzag-radial ; marsupium occupying the inner gills only.

ROSANORHAMPHUS.

Beak sculpture zigzag-radial.

Genus NODULARIA Conrad, 1853.

Nodularia Conran, Pr. Ac. N. Sci. Phila., 1853, p. 268.

Pharaonia Bourcuicnat, Mat. Moll. Aceph. Syst. Europ.,
1880, I, p. 3.

Zairia ROCHEBRUNE, Bull. Soc. Mal. Fr., III, 1886, p. 10.

Reneus JousSEAUME, Bull. Soc. Zool. Fr., XI, 1886, p. 481.
Shell elliptical to elongated, pointed behind about midway

up from the base, the post-basal part produced; beak sculpture

variable, irregularly zigzag-radial, often breaking into nodules,

950 NODULARIA

and extending in many cases over a part or all of the disk;
right valve with two, usually compressed, pseudocardinals, one
above the other, the lower the more elevated, separated by a
parallel-sided socket, and having one lateral; left valve with
two compressed pseudocardinals, both in front of the beaks,
and two laterals; cavity of the beaks moderate, not compress-
ed; anterior muscle scars deep, posterior shallow; nacre white.

Animal (of N. japanensis and N. e@quatoria) having the
inner gills alone filled throughout their entire length with ova,
forming a pad-like marsupium, united to the abdominal sac
or free from it.

Type, Unio douglasie Gray.

The genus Nodularia was established by Conrad in 1853 in
the Proceedings of the Academy of Natural Sciences of Phil-
adelphia with Unico douglasie Gray as the type. The name
Lanceolaria, with Unio grayanus Lea as its type, was given
by Conrad a few lines above this on the same page, but as he
used this name only in a subgeneric sense I think that the
name Nodularia should be used for the genus. In his descrip-
tions of the two groups on the following page Nodularia is
placed first.

I have placed under this name a large number of species
from southeastern Asia and Tropical Africa, which are fairly
typified by the Unio douglasie of Gray. In general the shells
are small to moderate in size, only one species, U. anodonte-
formis, becoming large. The structure is usually rather light,
the hinder end is nearly always pointed. The posterior base
of almost every species is more or less inflated, as are the fe-
male shells of many species of Lampsilis. Generally the form
varies from tong elliptical or ovate to very long. The beaks
are usually sculptured with zigzag-radial ridges and in a ma-
jority of the species this sculpture extends over the disk to a
greater or less degree, often breaking up into nodules or gran-
ulations. In such species as U. crispisulcata, the sculpture of
beaks and disks is almost strictly radial, showing, however,
slight zigzags and standing as a connecting link between the

NODULARIA 951

ordinary Nodularias, and Diplodon with almost or quite strict-
ly radial sculpture.

I have only been able to examine the soft parts of two spe-
cies, which I have placed in this genus, the Unio japanensis
of Lea and U. equatoria Morelet. In these there seemed to be
no striking differences in the more obvious characters from
the majority of the Uniones, but the embryos filled the inner
gills above as in Diplodon, showing their near relationship with
that great group.

Section JANCEOLARIA Conrad, 1853.

Lanceolaria Conrap, Pr. Acad. Nat. Sci. Phila., 1853, p. 268.

Shell ensiform, solid, with a distinct, pinched-up posterior
ridge, rounded in front, the posterior end sharp and generally
turned a little to the right or left; beaks low, their sculpture
nodulous, zigzag, often extending more or less over the sur-
face; pseudocardinals rather stumpy, ragged, striate above,
smooth below: anterior muscle scars distinct, the upper round,
very deep, appearing as if bored out; pallial line truncate be-
hind.

Animal unknown. :

Type, Unio grayanus Tea.

NopULARIA GRAYANA (Lea).

Shell exceedingly elongated, subinflated or inflated, inequi-
lateral, rather solid; posterior ridge pinched up, cord-like,
ending behind on the median line in a long, sharp point, some-
times turned down a little; umbonal region compressed ; lun-
ule long and well developed; anterior end rounded; base line-
nearly straight, full near the posterior end; surface more or
less sculptured, there being a series of subradial, slightly cor-
rugated ridges at the middle of the disk, and a number of
strong, subconcentric folds near the anterior end. ‘There is
often some zigzag-radial sculpture in the umbonal region; epi-
dermis olive, often with yellowish or green clouds, somewhat
silky when fresh; ieft valve with two strong, rough, subcom-
pressed pseudocardinals and two long, straight laterals; right

952 NODULARIA

valve with two pseudocardinals, the upper small, and a single

lateral; dorsal cavities shallow with a number of pits; muscle

scars well impressed, the hinder ones long; nacre brilliant
silvery, iridescent.

Tength 92, height 22, diam. 13 mm.

China.

Unio grayanus Lea, Tr. Am. Phil. Soc., V, 1834, p. 66, pl. rx,
fig. 26; Obs., 1, 1834, p. 178; pl. 1x, tie. 26.— Reeve, Conch,
syst., I, 1841, p. 118, pl. L.xxxvin, fig. 4—Hanzey, Biv.
Shells, 1843, p. 177, pl. xxiv, fig. 5.—Kuster, Conch. Cab.
Unio, 1856, p. 167, pl. xiv, fig. 5 —CHEnu, Man., 1859,
II, p. 142, fig. 700—ReEEve, Conch. Icon., XVI, 1865, pl.
xxv, fig. 191.—Hxrupe, Conch. Fluv., Nank., II, 1877, pl.
XVI, fig. 36.

Margarita (Umo)} grayanus Lea, Syn., 1838, p. 14.

Margaron (Unio) grayanus Lea, Syn., 1852, p. 21 ; 1870, p. 32.

Unio grayu GrirFity, Grif. Cuv., XII, 1834, pl. xx1, fig. 3.

Nodularia grayana Simpson, Syn., 1900, p. 806.

Lanceolaria grayana Haas, Con. Cab. Unio, 1910, p. 44, pl. 2,
figs. 1-5.

Unio (Nodularia) gracillimus Roti, Nachr. Deutsch. Mal.
Ges., 1904, p. 26, pl. tv, figs. b, ec.

The posterior end is sometimes turned a little to the right
or left, and the laterals show occasional traces of vertical stri-
ation. A most striking species and one that is apparently
quite abundant, judging from the number of specimens in col-
lections.

NODULARTA FRUHSTORFERT (Dautzenberg).

Shell much elongated, solid, very inequilateral, subinflated,
slightly arcuate; posterior ridge well developed, somewhat
rounded, slightly curved; ending in a point at the median line;
base line incurved in the middle, very full towards the poste-
rior end; surface with irregular growth lines, and a few, heavy,
irregular, nearly vertical folds on its hinder part, also having
finer, subradial folds in the umbonal region; epidermis brown-
ish; pseudocardinals strong, somewhat split up into radial den-
‘icles ; laterals long and slightly curved; muscle scars well im-

NODULARIA 953

pressed, the posterior one elongated; pallial line well marked;

nacre brilliant, rose-tinted, iridescent.
Length rio, height 31 mm.
Phuc-son (Annam).

Unio frithstorferi DAUTZENBERG, Jl. de Conch., XLVIII, 1900,
p. 429.—-Bavay and Dautzrenserc, Jl. de Conch., XLIX,
[GOL 5 plo u OSs. 1, 2:

Lanceolaria friihstorferi Haas, Con. Cab. Unio, 1910, p. 50,
pli.3, fig: 6, text he. 1
This species is close to U. gladiolus and grayana, but is

probably perfectly distinct. It differs from both of them in
having a slightly arcuate outline, in being decidedly full at
the post-basal region and in consequence having a much more
blunt posterior point. The specimen referred to in a footnote
on page 807 of the Synopsis, belonging to Mr. Bryant Walker,
is no doubt this species.

NopuULARIA BILIRATA von Martens.

“Shell elongate, heavy, convex above, compressed below,
mostly smooth except for the lines of growth; olive-brown,
not shining; very shortly rounded in front; produced poste-
riorly in a long beak, subacutely angled at the end, sculptured
above with two. elongate, parallel lire, the lower the more
prominent; dorsal margin slightly convex to the end of the lig-
ament, then sloping gradually to the posterior point; ventral
margin straight, slightly sinuous. Cardinal teeth sulcate on
both sides, unequal, in the right valve the anterior is much
compressed, small, the posterior heavy and broadly triangular ;
in the left valve, the anterior is moderately compressed, small,
the posterior broadly triangular; sinulus obsolete. Nacre
white; anterior adductor impressions moderate, posterior very
‘superficial.

Length 79, height 25, diam. 17 mm. Beaks in from 1-5—
1-6 of the length.” (von Martens).

Type locality, Tonkin.

Nodularia (Lanceolaria) bilirata von Marrens, Nachtr.

Deutsch. Mal. Ges., 1902, p. 133.—DAuTzENBERG and Fiscu-

ER). de“ Conch., WIE, 105; p. 204.

954 NODULARIA

Lanceolaria bilirata Haas, Con. Cab., Unio, 1910, p. 55, pl. 4,

figs. 3-5.

“Similar to the Japanese NV. oxyrhynca Marts., not only in
the two elevated lines that run down on the upper half of the
posterior end, but also in the proportionately shorter form, but
not quite so sharply pointed. Ona younger specimen, only 54
mm. in length, on the under side of the hinder end, some
grooves and swellings are noticeable, which recall those of the
Chinese NV. grayana Lea, and therefore establishes a natural
relationship with that group, but nothing of this is seen in the
adults.”

Dautzenberg and Fischer, (1. c.), consider this species iden-
tical with N. friihstorfert.

NoDULARIA LAEVIS von Martens.

“Shell elongate, thick, above angulated and slightly convex,
compressed below, smooth except for the growth lines, brown,
paler posteriorly, not shining, anterior end very shortly round-
ed, posterior produced in a long, narrow, straight beak, ob-
tusely angled at the end; posterior dorsal margin at first hor-
izontal, thence from a little before the end of the lgament
descending in a straight line; ventral margin slightly sinuous
in the middle and somewhat wider posteriorly ; cardinal teeth
two in both valves, triangular, sulcate, in the right valve the
posterior and in the left valve the anterior is much the heavier ;
lateral teeth elongate, nearly straight, one in the right valve,
slightly bifid, two in the left valve, parallel; sinulus not con-
spicuous. Interior very pale yellow, somewhat shining; an-
terior adductor muscle impressions deep, posterior superficial.

Length 73, height 15, diam. 10 mm. Beaks situated at 1-7
of the length.” (von Martens).

Type locality, Tonkin.

Nodularia (Lanceoiaria) levis von Marrens, Nachr. Deutsch.
Mal. Ges., 1902, p. 134.—DauTzenBerc and H. FIscHer.
Jide .Concheaiclil; 1005. p..204.

Lanceolaria levis Haas, Con. Cab. Unio, 1910, p. 57, pl. 4,
fics.'6:

NODULARIA 955

“Near to the Chinese V. grayana lea in form, but without
the V-shaped sculpture.”

Dautzenberg and Fischer, (1. c.), express the opinion that
this is the same as N. friihstorfert.

NoODULARIA GLADIOLUS (Heude).

Shell greatly elongated, solid, inflated, inequilateral, poste-
rior ridge strong, elevated, somewhat rounded, ending behind
in a point at or below the median line, sometimes turned down-
ward or to one side; umbonal region subcompressed ; surface
-with more or less faint, subvertical folds, and strong, irreg-
ular growth lines ; epidermis coarse, rough, brownish; pseudo-
cardinals something like those of grayana, but stronger and
rougher: laterals elongate, strong; muscle scars well impress-
ed, the hinder elongated; behind the laterals there is in each
valve a decided, elongated callus; nacre dull, flesh-color or
purplish.

Length 110, height 30, diam. 20 mm.

China.

Unio gladiolus Heupr, C. Fluv. Nank., II, 1877, pl. xv, fig. 35.
Nodularia gladiolus Stmpson, Syn., 1900, p. 807.
Lanceolaria gladiolus Haas, Con. Cab. Unio, 1910, p. 47, pl.

ae ies 2:

Closely related to N. grayana, but a larger, solider, ruder
species. The posterior ridge is not so sharp, there are, appar-
ently, no strong, concentric ridges on the anterior end, the epi-
dermis is rougher than in grayana and the nacre is far more
dull. The posterior calluses in the nacre of this species are
strongly developed and show traces of reticulation, these be-
ing feeble in the nearly allied N. grayana. ‘These peculiar
growths, the twisting and bending of the posterior end of the
shell and the vertical striation of the teeth are characters com-
mon to many apparently wholly unrelated forms of Unionide
found in Chinese waters, and with the singular inequality
caused by one valve being pushed over the other, seen in many
Ouadrulas, may be the result of some peculiarity of their en-

vironment. According to Bavay and Dautzenberg this species
attains a length of 160 millimeters.

956 NODUT,ARIA

NoDULARIA TRIFORMIS (Heude).

Shell much elongated, solid, inequilateral, subinflated ; pos-
terior ridge raised, rounded, ending behind in a point below
the median line; umbonal region compressed; anterior end
rounded; base line nearly straight; slightly incurved in front
of the middle, full behind the middle; surface with indications
of subvertical folds; epidermis brownish; teeth much as in N.
gladiolus, the laterals well impressed, the hinder ones elon-
gated; pallial line with indications of a sinus behind; nacre
whitish or bluish, dull brownish in the cavities.

Length 70, height 20, diam. 15 mm.

China.

Unio triformis Hrupr, Conch. F. Nank., II, 1877, pl. xv1, fig.

34.

Nodularia triformis Simpson, Syn., 1900, p. 807.
Lanceolaria triformis Haas, Con. Cab., Unio, 1910, p. 49, pl.

3, figs. 3-5.

Unio distortus Heupr, Conch. F. Nank., VIII, 1883, pl. ux,

figs. 122, 122).

Possibly only a small variety of gladiolus. ‘The shell fig-
ured by Heude appears to turn strongly to the right at the
posterior point and the one in the National Museum (an au-
thor’s specimen) turns sharply to the left. The epidermis is
rather more silky than that of gladiolus; the surface is not so
rude.

NopULARIA ACRORHYNCHA (von Martens).

“Shell elongate, compressed, epidermis rather silky, black-
ish-brown, shining, shortly rounded in front, posteriorly sculp-
tured for the most part with subperpendicular, elongated, par- -
allel tubercles and produced into a long, acute beak, with an
elevated carina on the upper side extending to the extremity ;
beaks depressed, eroded. Nacre pale reddish or yellowish-red,
slightly showing posteriorly the external tubercles. Cardinal
teeth of the left valve two, triangular, subequal, rugose, the
anterior directed forward; in the right valve the anterior is
small, compressed, nearly parallel to the dorsal margin, the
posterior broadly triangular, rugose; lateral teeth elongate,

NODULARIA 957

straight, in the left valve two, slightly rugosely sulcate, in the
right valve one, slightly transversely sulcate. Anterior muscu-
lar inipression large, round, very near to the anterior margin;
pallial line in front rather wide, pitted, simple behind.

Length 125, height 34, diam., under the beaks 15 mm. Beaks
situated at 1-6 of the length, ligament extends to 4-6 of the
length.” (von Martens).

Type locality, Naemigang River, near Hatanggyong, and in
a tributary of the Imjingang, Korea; also in the Kwanchon-
gang near Pukchan, north of Naga-Naju.

Unio acrorhynchus VON Martens, 5. B. Nat. Fr., 1894, p. 214.

—Simpson, Syn., 1900, p. 861.

Unio (Lanceolaria) acrorhynchus von Martens, Zool. Jahrb.,

Supple Vi 2905. p:.53, pl. 1, fis. 4.

Lanceolaria acrorhyncha Haas, Con. Cab., Unio, 1910, p. 61,

pl. v, fig. 4.

“Groups with the Chinese U. grayanus Lea and the Japan-
ese U. oxyrhynchus Marts., but larger and proportionately
more compressed than either, not so low as grayanus and in
the general appearance more like oxyrhynchus, but longer and
at the posterior end more equally pointed above and below,
whereas in oxyrhynchus the posterior part of the basal margin
scarcely ascends, so that the point is lower; also in acrorhyn-
chus the carina from the beaks to the posterior end is more
prominent. With reference to the sculpture, in grayanus the
vertical folds are more regular, more numerous, about 20, and
consequently closer and also smaller, in LU. acrorhynchus they
are less numerous, about 8, broader and irregular, in U. oxy-
rhynchus they are similar, but decidedly weaker. On com-
parison of adult examples, the differences are very clear, but
the young shells resemble each other very much and especially
in a young example of U. acrorhynchus from Massangabe,
which has the same diameter as U. grayanus of the same size.”

NopuLARTA OXYRHYNCHA: (von Martens).

Shell elongated, subsolid, scarcely inflated, inequilateral ;
posterior ridge full, pinched up, cord-like, ending behind in a
point at or above the median line ; anterior end rounded, some-

958 NODULARIA

times a little angled above; base line very slightly curved,
quite full near the posterior end; surface with irregular growth
lines, but with no other sculpture in the specimens seen; epi-
dermis brownish, cloth-like ; pseudocardinals triangular, two in
the left valve, one and a compressed one in the right; laterals
long, slender, straight ; muscle scars rather shallow, the hinder
ones slightly elongated; nacre bluish, dirty brownish in the

cavities. .

Length 65, height 20, diam. 12 mm.
Japan.

Unio oxyrhynchus von Martens, Mal. Blatt, VII, 1861, p. 57.
—Koseutr, Abh. Senck. Nat. Ges., XL, 1879, p. 420, pl. x11,
figs. 3, 4.—PFEIFFER, Nov. Conch., V, 1879, p. 192, pl. CLV1I,
figs. 4, 6.

Nodularia oxyrhynchus SIMPSON, Syn., 1900, p. 807.

Lanceolaria oxyrhyncha Haas, Con. Cab., Unio, 1910, p. 53,
plea, tress ie 2s
Less solid, more compressed and higher than any of the

related species. In all the examples I have seen there is only

irregular, concentric sculpture, though it is probable that some
specimens might show traces of corrugation.

Section CYLINDRICA Simpson, Igoo.

Cylindrica SIMPSON, Syn., 1900, p. 807.

Shell inflated, solid, cylindrical, smooth, with a rounded pos-
terior ridge; teeth heavy, pseudocardinals radiate, curved.

Type, Nodularia cylindrica Simpson.

NODULARIA CYLINDRICA Simpson.

Shell greatly elongated, inflated, rather solid, slightly ar-
cuate, very inequilateral, rounded in front, with a low, round-
ed posterior ridge, which ends behind in a rounded point near
the base line; the dorsal slope is obliquely truncated ; ligament
large, long; surface apparently without sculpture, with the
exception of slight, concentric ridges; epidermis thick, brown;
dorsal line wavy at the hinder end where the point is turned

NODULARIA 959

a little to one side; pseudocardinals broken up into several
slightly curved, subradial denticles; anterior scars deep and
large.

Length 155, height 45, diam. 38 mm.

China.

Unio grayanus SCHRENCK, Reis und Forsch. in Amur-Lande,

1867, p. 694, pl. xxvul, figs. 1-3.

Nodularia cylindrica Stmpson, Pr. Ac. Nat. Sci. Phila., 1900,

p. 84; Syn., 1900, p. 807.

Lanceolaria cylindrica Haas, Con. Cab., Unio, 1910, p. 58,

pl. 5, figs. 1-3.

Schrenck supposes this species to be the Unio grayanus of
Lea, but it is very different. There is no pinched up or ele-
vated posterior ridge whatever as there is in that and all the
species 1 have placed with it. It is an almost cylindrical,
smooth shell, with very thick, apparently silky, epidermis. The
line of junction between the valves behind is wavy and the
hinder part of the shell is turned to one side a little, as is the
case in N. gladiolus.

Section NODULARIA S. S.

Characters the same as the genus.

Group of NV. douglasie.

Shell olive to blackish, subsolid : surface more or less covered
with nodules arranged in subradiating or chevron-shaped pat-

terns.

NoODULARIA DOUGLASL® (Gray).

Shell somewhat elongated, subsolid, subinflated, inequilat-
eral: beaks full, with nodular, zigzag-radial sculpture ; anterior
end rounded; base line straight or slightly incurved in the
middle, full behind; posterior ridge moderate, ending in a
point about at the median line; surface in the umbonal region
sculptured with nodulous chevron-shaped or irregular corru-
gations, the remainder of the shell usually smooth; epidermis

960 NODULARIA

varying from greenish through olive to black, usually smooth

and shining; pseudocardinals compressed, the two in the left

valve often partly united; laterals nearly straight, granular,
beak cavities moderately deep; muscle scars shallow; nacre
bluish-white.

Length 55, height 27, diam. 18 mm.

China; Amurland; Formosa; Cambodia ?

Unio douglasie Gray, Griff. An. King., XII, 1833, (p. 601 in-
dex, 1834) pl. <xa,~fieae.

Nedularia dowglasie SIMPSON, Syn., 1900, p. 808.— Haas,
Con. Cab., Unio, 1910, p. 68, pl. vi, figs. I-10.

Unio murchisonianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 33,
pl. mm, fig. 6; Obs., I, 1834, p. 145, pl. 111, fig. 6—HANLEy,
Biv. Shells, 1843. p. 177, pl. xx1, fig. 53.—Kuster, Conch.
Cab. Unio, 1856, p. 166, pl. xiv, figs. 3, 4—CHENU, Man.,
1859, Il, p. 142, fig. 701—Sowersy, Conch. Icon., XVI,
1866, pl. Xxxvut, fig. 207.

Margarita (Unio) murchisonianus Lea, Syn., 1836, p. 14;
1838, p. 14.

Margaron (Unio) murchisonianus Lea, Syn., 1852, p. 21; 1870,
Dp: 32:

Unio osbecki Puiiivrt, Zeits. fiir Mal., 1845, p. 164; Conch.,
III, 1847, p. 45, pl. m1, fig. 1—Kustrr, Conch. Cab., Unio,
1861, p. 236, pl. LXxrx, fig. 3—Sowerry, Conch. Icon., XVI,
1868, pl. LXTxX, fig. 353.

Margaren (Unio) osbecki LEA, Syn., 1852, p. 21; 1870, p. 32.

Unio nux-persicus DuNn«eER, Zeits. fiir Mal., 1848, p. 83.—
Muscraver, Phot. Conch., 1863, pl. 1, fig. 10.—SOWERBY,
Conch: Teonfox V 1, 1868; ‘pl. pscxanne hess 735

Margaron (Unio) nux-persicus L&a, Syn., 1870, p. 32.

Unio wrighiti Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 75; ie
Ac. N.Sei. Phila’, VI21868, p. 263, pla xxi Heo7 VOps.,
XIP, 1860)795 43, pl acxcxix, feo7

Margaron (Unio) wrightii Lea, Syn., 1870, p. 32.

Unio sculptus Desuayrs, Bull. Nouv. Arch. Mus., IX, 1873,
p. 9, pl. 1, figs. 3, 3a.—Herupr, Conch. F. Nank., III, 1877,
plex Xiv, seas 1

Unio dactylinus Hxupr, Conch, F. Nank., 1885, pl. LxXv.

NODULARIA g6I

Unio pictorum var. longirostris \WWESTERLUND, Kong so. vet.

Ak. Hand, XIV, No. 12, p. 74.

Unio schrencki WrSTERLUND. Where described?
Unio abbreviatus \VESTERLUND. Where described?

An abundant and variable form, which has received a num-
ber of names. Some of the forms are probably worthy of va-
rietal distinction. ‘The general form is much like that of
Lampsilis subrostrata of Say, but all the shells appear to have
a post-basal swelling. It is probable that the Unio pictorum,
which Westerlund credits to Amurland, is a form of this. The
sculpture sometimes extends well over the disk.

Var. shanghaiensis (Lea).

Shell smooth, usually quite dark, and larger than the typi-
cal form.

Length 67, height 30, diam. 23 mm.

China; Eastern Siberia; Japan.

Umo shanghaiensis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p.
Peas lene. JN.ock Phila. V5.1860; pi 242, pl. xxxvi,'fig.
121; Obs., VII, 1860, p. 60, pl: xxxvi, fig. 121.—REEVE,
Conch. Icon., XVI, 1865, pl. xx1, fig. 96.

Nodularia douglasie var. shanghaiensis SIMPSON, Syn., 1900,
p. 808.—Haas, Con. Cab., Unio, 1910, p. 71, pl. vu, fig. 1.

Unio pictorum var. amurensis Mousson, J. de Conch., XX XV,
Eoo7, p. 26, pl. 1, fic. &.

Sometimes no larger than typical form, but smooth and
darker.

Var. nipponensis (von Martens).

A rather small, dark form, either nearly smooth or having
considerable sculpture on the disk. I have seen shells from
Japan, which are nearly smooth and as large as any specimens
of shanghaiensis.

China; Amurland ; Japan.

Unio nipponensis voN Martens, S. B. Nat. Fr., 1877, p. 119.
—Kose.t, Abh. Senck. Nat. Ges., XI, 1879, p. 422, pl. xu,
fie.2:

Nodularia douglasie var. nipponensis Stmpson, Syn., 1900, p.
809.—H as, Con. Cab., Unio, 1910, p. 72, pl. vit, figs. 2, 3.

962 NODULARIA

Var. sinuolata (von Martens).

“Shell elongate, swollen posteriorly, with a distinct point and
with the ventral margin somewhat incurved. Beaks situated
at 2-7 of the length, moderately eroded, anterior part of the
dorsal margin only slightly sloping and passing with a broad,
scarcely noticeable angle into the short and symmetrically
rounded anterior margin, the posterior part of the dorsal mar-
gin as far as the end of the lateral teeth is almost horizontal,
then in a very obtuse angle it slopes and with the much
stronger ascending basal margin forms a distinct point. Sculp-
ture only weak remnants of small folds behind the eroded por-
tion, elsewhere only concentric growth-lines, which towards
the basal margin become more pronounced. Epidermis shin-
ing, dark greenish-brown. Nacre silvery white, in many speci-
mens somewhat ocre-yellowish towards the beaks. Cardinal
teeth compressed, the two in the right valve about equal and
parallel, the upper one in the left valve much more prominent
than the very weak under one; the lower lateral tooth in the
right valve is wholly or almost wholly wanting.

a) Length 56, height at beaks 24, at wing 26, diam. 20 mm.

b) Length 50.5, height at beaks 21, at wing 22, diam. 18
mm.” (von Martens).

Type locality, Naemingang River, near Hatanggyoen, Prov-
ince of Choellado and the mouth of the western tributary of the
Imjingang. near Ichoen, Province of Kangwoendo, Korea.
Unie douglasie var. sinuolatus von Martens, Zool. Jahrb.

Suppl., VII; 190s, p57.

Nodularia douglasie sinuolatus Haas, Con. Cab., Unio, 1910,

P1735 pla Vinee. 6:

“This form by its somewhat expanded basal margin and
the strong inflation of the posterior third of the shell is very
remarkable. It is quite possible that this feature is only an
unusual strong expression of the characteristic female form,
that in this portion lie the swollen gills, in which the embryos
live. In the Naemingang another example was found, which
represents the usual form of dowglasie in Korea, rather com
pressed and high, with a straight basal margin and without

NODUI,ARIA 963

any inflation, 58 mm. long, at the beaks and at the wing 28
and 20 mm. in diameter; this perhaps is the male form. But
it is remarkable that in all of the specimens before me, in-
cluding the possible males, the second (lower) lateral tooth
of the right valve is wholly or almost wholly wanting.

Compare with Unio douglasie var. osbeckii Phil., in Heude
Conch. Fluv. Nank., pl. 65), fig. 1281, which represents the
Chinese analowae of this form.”

Var. taiwanica Pilsbry.

“Shell oblong, narrow, inflated, rather solid, the dorsal and
ventral margins subparallel, the former slightly arcuate, an-
terior end rounded, basal margin straightened in the middle,
posterior end long, somewhat pointed. Beaks full, swollen,
worn, but showing traces of oblique corrugation on the an-
terior and posterior slopes, situated at the anterior two-sev-
enths of the length. Exterior covered with a blackish cuticle,
somewhat wrinkled along growth-lines. Interior white, iri-
descent posteriorly. Cardinal teeth compressed, strong, single
in the right, double in the left valve. Laterals moderately
strong, rather short.

Length 49, alt. 25, diam. 19.7 mm.” (Pilsbry).

Type locality, Formosa.

Nodularia douwglaske taiwanica Pinsspry, Pr. Ac. Nat. Sci.

Phila., 1905, p. 750.

“A mussel closely related to N. dowglasie of China, but
showing only very weak traces of corrugation.”

Var. crassidens Haas.

“Among the typical specimens of N. dowglasie of nearly all
localities, there occur heavy, inflated shells with extremely
thick and jagged cardinals and strongly curved laterals, upon
which I bestow the subspecific name of crassidens. 1 have
examined specimens from Hainan, from Hunan and from
Ningpo, Northern China.” (Haas).

Nodularia douglasie crassidens Haas, Ann. Mag. Nat. Hist.,

(8), VI, 1910, p. 499; Con. Cab., Unio, 1910, p. 75, pl. vit,

figs. 4, 5.

964 NODULARIA

NoDULARIA PLICULOSA (von Martens).

“Shell elliptic-oblong, inflated, epidermis brown or blackish,
shortly rounded in front, elongate and obtusely subrostrate
behind, sculptured with sparse, short, radiating, compressed
folds, subparallel in the umbonal region, often interrupted and
usually obliquely descending in front, zigzag posteriorly ; ven-
tral margin straight in the young, slightly sinuous in the
adults; posterior margin above slightly oblique, subtruncate
in the middle, slightly ascending below. Nacre bluish. Car-
dinal teeth compressed, rather stout, the anterior one of the
left valve much elongated, those of the right valve are sub-
parallel, the lower the stronger; lateral teeth long, slightly
curved, smooth. /

a) Length 45, height 22, diam. 15 mm. Beaks situated at
1-4 of the length. [Ligament extending to 2-3 of the length.

b) Length 33, height 15, diam. 10.5 mm. Beaks at 2-7 of
the length. Ligament extending to about 2-3 of the length.”
(von Martens).

Type locality, (a) Singei in Southern Korea and (b) be-
tween Okkwa and Changpyoeng, Northern Korea.

Unio pliculosus von Marrens, S. B. Nat. Fr., 1894, p. 216.—

Simpson, Syn., 1900, p. 862.
Nodularia pliculosa Haas, Con. Cab., Unio, tg10, p. 76, pl.

vil, figs. 7-11.

NODULARIA VERRUCIFERA (von Martens).

“Shell oblong-elliptical, slightly inflated, solid, grayish-green,
sculptured anteriorly with rows of warts curving upwards,
ending in an acute angle at the middle of the shell; rounded in
front; posterior portion elongate, subrostrate, sculptured with
rather numerous, radiating, compressed folds; ventral margin
straight; posterior margin strongly oblique above and some-
what ascending below. Nacre white, reddish-yellow in the
centre. Cardinal teeth rather heavy, crenate, the anterior one
of the left valve much the longer, the upper one of the right
valve slight, small; lateral teeth strong, moderately elongate,
nearly straight, rugose.

NODULARIA 965

Length 37, height 18, diam. 12 mm. Beaks situated at 3-5
of the length; ligament extending to 3-4 of the length.” (von
Martens).

Type locality, Hangang River, Middle Korea.

Unio verrucifer VON Martens, S. B. Nat. Fr., 1894, p. 216.—

SIMPSON, Syn., 1900, p. 862.

“The Chinese Unio douglasie Gray (murchisonianus Lea)
is very close to this species, but is more elongate posteriorly
and consequently the beaks are proportionately more anterior
and the height less.”

NOpULARIA BO&TTGERT (Neumayr).

“Shell thin, inequilateral, rather long-oval, slightly inflated,
beaks situated in the first third of the length; rounded in front,
feebly keeled behind, rounded, a little pointed. Beaks not
prominent, strongly wrinkled, eroded. Posterior slope feebly
defined. Hinge very feebly developed, in each valve a thin,
anteriorly directed, long, lamelliform cardinal tooth, in the left
valve is a second rudimentary tooth parallel with the first.
Lateral teeth feeble. Anterior muscular impressions slight,
posterior very faint. Nacre white, iridescent. Epidermis
blackish-brown.

Length 55, height 28, diam. 20 mm.” (Neumayr).

Type locality, Region of Tsching-kiang, Province of Kiang-
su, China.

Unio bettgeri NeuMAyR, Ergebnisse d. Reise Szecheny Ost-

asien, II, 1898, p. 645, pl. 11, fig. 3.

“Of all the allied species, Unio sculptus Deshayes, from the
Province of Petschili, China, is the nearest and in fact the
figure of that species in contour, size, sculpture and indeed in
the great part of all the characters shows no important differ-
ences ; only in the structure of the hinge is there such a marked
difference that it is impossible to bring them together as one
species. In Unio sculptus the posterior cardinal tooth is tri-
angular, whereas in Unio bettgeri it is a rudimentary, forward-
projecting lamella. Unio pfisteri Heude and rufescens Heude
also clearly differ in the character of the hinge; there is also

966 NODULARIA

a very well recognizable external difference, even if the inner
one was not so noticeable. Unio douglasie Gray is also re-
lated, but differs in its keeled anterior end and olive-green
color.”

NopuLARIA porRI ( Wattebled).

Shell small, elongated, inflated, subsolid, inequilateral ; beaks
apparently full; posterior ridge well developed, sharp, ending
in a point about on the median line; anterior end rounded;
base line straight, full behind the middle, from which it is
slopingly truncate to the posterior end; outline of the dorsal
slope curved; surface with very delicate growth lines and
some very slight corrugations on the umbonal region and the
dorsal slope; epidermis dark brown, shining; pseudocardinals
elevated, ragged, subcompressed, granular and somewhat den-
ticulate; laterals nearly straight; beak cavities rather deep;
muscle scars impressed; nacre bluish, sometimes yellowish in
the cavity, thinner and brilliantly iridescent behind.

Length 36, height 15, diam. 13 mm.

Cochin China; Anam; Mekong River; Tonquin.

Unio dorrt WATTEBLED, Jl. de Conch., XXXIV, 1886, p. 71,

plw, ne. 5:

Nodularia dorri Simpson, Syn., 1900, p. 809.—Haas, Con.

Cab., Unio, 1910, p. 81, pl) vin, figs. 15 2!

Close to forms of N. douglasie, but very much smaller, hav-
ing a more sharp and elevated posterior ridge and brighter
iacre:

NODULARIA DENSERUGATA Haas.

“Shell elongate-elliptical, rather solid and inflated, rounded
in front. distinctly biangulate behind. Posterior ridge rather
high, rounded. Basal margin almost straight. Beaks not prom-
inent, situated at 26-100 of the total length, greatly eroded;
their sculpture covers the greater part of the disk and consists
of concentrical, wavy wrinkles standing very close. Epidermis
of a dull blackish gray. Hinge consisting of two cardinals and
two laterals in the left, one cardinal and one lateral in the

NODULARIA 967

right valve. Cardinals rather solid, stumpy, that of the right
valve accompanied in front by a low, lamellar auxiliary tooth.
Laterals nearly straight, high. Interval short, rather smooth.
Anterior cicatrices distinct, deep; posterior distinct and very
faint. Dorsal cicatrices united to a narrow groove situated at
the inner side of the interval. Beak-cavities rather deep. Na
cre silvery.

Length 53, height 26, diam. 18 mm.” (Haas).

‘Type locality, Hainan.
Nodularia denserugata Haas, Ann. Mag. Nat. Hist., (8), VI,

1910, p. 496; Con. Cab., Unio, 1910, pl. vii, figs. 3-4.

NopuLarRia Brw-& (Kobelt).

Shell somewhat elongated, solid, subinflated, inequilateral ;
beaks apparently rather full, their sculpture not observed ; pos-
terior ridge well marked, subangular, ending in a sharp point
on the median line; base line nearly straight in front, full be-
hind the middle ; anterior end rounded, subangular above; out-
line of dorsal slope evenly curved; surface with faint, uneven,
growth lines; epidermis brown or blackish, shining; pseudo-
cardinals subsolid, somewhat split into denticles; laterals
curved; beak cavities impressed; muscle scars rather deep,
small; nacre dirty flesh-colored or brownish with a coppery
or bronzy iridescence.

Length 45, height 22, diam. 16 mm.

Lake Biwe, Japan.

Unio biwe Kosgir, Abh. Senck. Nat. Ges., XI, 1879, p. 425, pl.

XXUI, figs. 2-4.

Nodularia biwe Simpson, Syn., 1900, p. 810.—Haas, Con.

Cab., Unio, 1910, p. 94, pl. 1x, figs. 6-8.

A small, solid, shining, dark colored species. At the time
ot writing the Synopsis I had never seen this shell, but have
since had an opportunity of examining authentic specimens.
It should be placed in the group of N. dowglasie instead of
that of N. japanensis. It differs from the latter species in be-
ing considerably more wedge-shaped when viewed from above,
and in having different nacre.

968 NODULARIA

NODUL,ARIA DIGITIFORMIS (Sowerby).

Shell elongated, slightly arcuate, solid, inflated, inequilat-
eral; beaks full; outline of dorsal slope curved; anterior end
rounded; base line incurved but very full behind the middle;
posterior basal part obliquely truncate; posterior ridge full,
slightly double, ending below the median line in a narrow bi-
angulation; epidermis black, smooth; pseudocardinals large,
ragged; laterals elongated ; nacre white.

? Length 100, height 37 mm.

India.

Unio digitiformis Sowrrsy, Conch. Icon., XVI, 1868, pl. Lxv,

fig. 333.

Nodularia digitiformis SIMPSON, Syn., 1900, p. 8090.

I have never seen this species, which seems something like
a large, elongated, smooth N. dowglasic. It is more solid than
that species and is slightly arcuate according to the figure,
which is probably taken from an old shell.

Group of Nodularia japanensis.

Shell solid, elliptical, subrhomboid or oval, biangulate, round-
ed or pointed behind and often produced at the posterior base ;
posterior ridge low or scarcely developed; beaks moderately
full; sculpture zigzag-radial ; surface of the valves concentric-
ally striate or more or less covered with corrugated, chevron-
shaped sculpture, which often becomes somewhat nodulous ;
epidermis greenish and sometimes rayed in young shells, be-
coming brown or blackish when adult.

Animal having the inner gills wider than the outer in front,
equal behind, free from the abdominal sac throughout, united
to the mantle to the extreme posterior point ; palpi rather large,
long; mantle double on the border and toothed below; bran-
chial opening large, with well-developed, brown papillz; anal
opening large, with small, tubercular papillze on its inner edge,
covered with wart-like papilla inside; superanal opening not

closed below.

NODULARIA 969

NopuLARIA JAPANENSIS (Lea).

Shell rhomboid elliptical, more or less elongated, convex,
inequilateral, rounded in front, base line nearly straight, or
somewhat curved, usually full behind the middle; posterior
ridge but moderately developed, usually feebly double, ending
in a faint biangulation below the median line; beaks not full
or high, their sculpture zigzag-radial; surface more or less
covered with nodulous sculpture, which is usually arranged in
zigzags or chevron-shaped figures, the nodules often united
together into corrugated ridges; epidermis varying from rich
green in young shells to brown or black, dull or shining ; pseu-
docardinals subcompressed to subsolid, rough, two in each
valve, the upper one of the right valve small; laterals with
traces of vertical striation; muscle scars not deep; beak cavi-
ties shallow ; nacre dirty or lurid brownish.

Length 62, height 33, diam. 19 mm.

Length 40, height 30, diam. 15 mm.

Japan.

Unio japanensis Lua, Pr. Ac. N. Sci. Phila., III, 1859, p. 153;
Wee Ne Sci, Phuila.- lV, 18600, p. 244; pl. xxxvi, fir. 123;
Obs.,. VII, 1860, p. 62, pl. Xx xvi, fig. 123.—Kustrer, Conch.
Cab. Unio, 1862, p. 227, pl. xcru, fig. 4.—Sowersy, Conch.
Icon., XVI, 1868, pl. Lxxx, fig. 420.

Margaron (Unio) japanensis Lea, Syn., 1870, p. 31.

Nodularia japanensis Simpson, Syn., 1900, p. 809.—Haas,
Con. Cab., Unio, 1910, p. 85, pl. viii, figs. 5-8.

The type of this is not in the Lea collection, there being
only a large shell, whose measurements are given above. The
species varies considerably in the degree of sculpture, some
specimens being only faintly nodulous, while others are strong-
ly and densely sculptured throughout.

Var. jokohamensis (von Thering).

Differs from the typical form in being more blunt and
rounded behind. It seems to be connected by intermediate
forms.

Japan.

970 NODULARIA

Unio japanensis KopeLt, Abh. Senck. Nat. Ges., XI, 1879, p.
AB2s Pls ily Mies: ue

Unio jokohamensis von IwertInc, Abh. Senck. Nat. Ges.,
XVI 18o3epe rss:

Nodularia japanensis var. jokohamensis Stmpson, Syn., 1900,
p. $10.—Haas, Conch. Cab., Unio, 1910, p. 87, pl. vai,
figs. 9-13.

NODULARIA HACONENSIS (von Ihering).

Shell rhomboid elliptical, convex, inequilateral, subsolid,
rounded in front, slightly curved on the base line and but little
produced at the postericr base; obliquely subtruncate on the
posterior slope; posterior ridge low, often with a slight ten-
dency towards being double; surface more or less strongly,
concentrically sulcate, showing faint traces of nodular sculp-
ture on the middle of the disk; epidermis dirty tawny or
brownish, somewhat cloth-like; pseudocardinals rather strong,
rough, not split into dentillations; laterals well developed,
curved; beak cavities well impressed; muscle scars well mark-
ed; nacre dirty, lurid brownish or lead-colored.

Length 47, height 28, diam. 16 mm.

Japan.

Unio haconensis VON IHERING, Abh. Senck. Nat. Ges., XVIII,

T8035 p., LOlasie-h3.

Nodularia haconensis Stmpson, Syn., 1900, p. 810.—HAas,

Con, ‘Cab. (Unio, 1910, sp. SO) pli, ossar=3.

Close to N.. japanensis and possibly a variety of it, but dif-
fering in having well marked, concentric sculpture, in being
almost destitute of nodules and having a pale brownish or
tawny epidermis.

NopuULARIA BRANDTII (Kobelt).

Shell rather short, elliptical or rhomboid elliptical, very solid,
subinflated, inequilateral ; dorsal outline almost evenly curved ;
basal outline curved; posterior ridge moderate, ending below
the median line in a dull point ; anterior end rounded; surface
with irregular growth lines, blackish-olive; beaks prominent ;

NODUL ARIA g7I

teeth strong, the laterals decidedly curved; nacre brownish
flesh-colored ; muscle scars distinct.

Length 40, height 27, diam. 17 mm.

. Japan.
Unio brandtu Koper, Abh. Senck. Nat. Ges., XI, 1879, p.

AOR RTT, fast TS:

Nodularia brandtui Simpson, Syn., 1900, p. 810 —Haas, Con.

Cab., Unio, 1910, p. 102, pl. 1x, figs. 9-10.

This is something like NV. haconensis, judging from Kobelt’s
description and figures, but appears to be very much more
solid and a darker shell. A dorsal view shows it to be some-
what wedge-shaped.

For this species and N’. parcedentata Haas, (Conch. Cab.,
Unio, 1912, p. 102), has established a new section, /nversidens.

NopULARIA PARCEDENTATA Haas.

“Shell irregularly rhomboid, quite thin and inflated. An-
terior end straight above, thence regularly rounded; ventral
margin straight or slightly convex. Posterior point not prom-
inent; posterior margin obliquely rounded; dorsal margin
nearly straight. Beaks situated anteriorly at 24-100 of the
total length, prominent in young shells, but in older ones lower
than the highest point of the dorsal margin, eroded, but in
young shells sculptured with wavy wrinkles, of which remnants
are visible on the areola of the adults. Posterior slope high,
triangular, compressed and, owing to the elevated posterior
ridge, is: distinctly separated from the rest of the shell, the
inner as well as the upper areal carinz are also recognizable
as indistinct lines. The areola is small, compressed. Liga-
ment long, strong; sinulus nearly obsolete, long, lanceolate;
sinus short, triangular. From above the outline of the shell
is sharply pointed in front, rapidly increases in width, reach-
ing its maximum at about the center of the shell, thence grad-
ually decreasing to the posterior end. Epidermis shining black,
covered at both ends with a rust-colored deposit. Hinge very
variable. Only one cardinal tooth in each valve. That of the
right valve lies in front of the beak, square and jagged above;

972 NODULARIA

that of the left valve lies under the beak and is stumpy, trian-
gular and smooth. Laterals short, thick, a little curved, 1-2 in
each valve. In the four specimens before me they are as
follows:

RIGHT LEFT
a)

b) 2 2
@) I 2
d) 2 2

The angle of the cardinal teeth is 30°; of the laterals 0°.
Both the anterior and posterior muscular impressions are
merged; those of the posterior retractors, however, show a
tendency to be differentiated ; dorsal scars united in a deep pit
under the interval. Nacre reddish in the beak cavities, bluish
towards the margin.

Length 50, greatest height 36, at beaks 30, diam. 22 mm.”
(Haas).

Type locality, Japan.

Nodularia parcedentata Haas, Con. Cab., Unio, 1910, p. 104,

pl. xia, figs. 3-4; Nachr. Deutsch. Mal. Ges., 1911, p. 43.

NODULARIA CONTINENTALIS Haas.

“Shell elongate-elliptical, solid, inflated, somewhat truncated
in front and slightly arcuate behind. Posterior ridge moder-
ately rounded. Basal margin slightly sinuate at its posterior
part. Beaks not prominent, eroded, situated at 21-100 of the
total length; their sculpture is not to be seen when adult, in
young sheils it consists of few concentrical, slightly looped
ridges, the posterior loops running upwards across the pos-
terior slope. Epidermis of a rather dull black. Hinge con-
sisting of two cardinals and two laterals in the left, one car-
dinal and one lateral in the right valve. Cardinals solid,
stumpy, jagged on the surface, a narrow lamellar auxiliary
tooth standing in front of the one of the right valve. Laterals
long, high and curved. Interval short, broad, covered with
small. denticular structures. Anterior cicatrices united to a

NODULARIA 973

narrow, short groove situated at the inner side of the interval.
Beak-cavities deep. Nacre silvery, brilliant.

Length 62, height 36, diam. 25 mm.” (Haas).

Type locality, Hunan, Middle China..

Nodularia continentalis Haas, Ann. Mag. Nat. Hist., (8), VI,
IQIO, p. 497; Con. Cab., Unio, 1910, p. 92, pl. rx, figs. 4-5.
“Very near to Nod. japanensis Lea of Japan, the first form

of this group recorded from the continent.”

NoODULARIA OMIENSIS (von Heimburg).

Shell obovate or subrhomboid, narrow in front, rather thin,
convex, inequilateral; beaks apparently not very full; anterior
end rounded; base line curved, full behind the middle; poste-
rior end obliquely subtruncate above, somewhat biangulate
below ; surface with rather fine, concentric ridges, and more or
less corrugated subnodulous sculpture; epidermis brownish
or blackish; pseudocardinals subsolid; laterals curved; beak
cavities moderate; muscle scars not deep; nacre bluish-white,
richly iridescent.

Length 51, height 28, diam. 15 mm.

Province of Omi, Japan.

Jnio omiensis VON Heimburc, Nach. Deuts. Mal. Ges., XVI,
1884, p. 93; Jahrbuch Mal. Ges., XIV, 1887, p. 2, pl. 1, figs.
B52:

Nodularia onuensis SIMPSON, Syn., 1900, p. 810.—HAas, Con.
Cab., Unio, 190, p. 95, pl. 1x, fig. I1.

Thinner, more obovate and with a richer colored nacre than
N japanensis. I have seen a single valve of what may be this
species, which is much more strongly corrugately sculptured
than the figure given by von Heimburg. It does not differ any
more in this respect than specimens of N. japanensis do.

NoODULARIA HIRASEI Haas.

‘Shell wedge-shaped, thick, heavy, moderately inflated. An-
terior margin short, regularly rounded; ventral margin quite
convex; posterior point blunt; posterior margin oblique; dor-
sal margin slightly curved. Beaks well in front at one-fifth
of the total length, not very prominent, eroded, rather inflated ;

974 NODULARIA

their sculpture, in young shells, consisting of concentric, wavy
wrinkles, which become zigzag-shaped posteriorly and are
continued over the posterior ridge in curved, parallel lines
over the dorsal area. . Area low, somewhat compressed, with
indistinct areal-lines. Areola very small, compressed. Ljiga-
ment long and strong. Sinulus broad, lance-shaped. Sinus
short, triangular. Epidermis black with a light silky gloss.
Dorsal outline lance-shaped, quite blunt in front, abruptly
increasing in width, the maximum being at one-fourth of the
length of the shell; thence gradually decreasing to the sharp
posterior end. Hinge with one cardinal and one lateral in
the right, two cardinals and two laterals in the left valve.
Cardinal tooth of the right valve blunt, strong, very jagged,
in front of it a smaller, weaker, lamelliform auxiliary tooth;
anterior cardinal of the left valve small, low, posterior elongat-
ed, high jagged. Interval short, broad. Laterals long, strong,
in the left valve the lower is the stronger. Angle of the car-
dinal teeth 15° ; of the laterals 10°. Anterior muscular impres-
sions deep, that of the adductors united with that of the upper
retractors; posterior faint; dorsal lying in a row under the
interval. Mantle-pad in front quite strong, becoming’ flat-
tened posteriorly. Nacre reddish, bluish posteriorly.

Length 79, height 46, diam. 30 mm.” (Haas).

Type locality, Yamashiro, Japan.
Nodularia hirasei Haas, Nachr. Deutsch. Mal. Ges., 1911, p.

45; Con. Cab., Unio, 1910, p: 96, pl. xiia, figs. 1-2.

Group of Nodularia reiniana.

Shell elliptical oval, very solid, truncated in front and some-
what biangulate behind, slightly produced at the posterior
base ; beak sculpture not known; pseudocardinals heavy, elon-
gated, parallel with the dorsal line. Animal unknown.

NoDULARIA REINIANA (Kobelt).

Shell irregularly long ovate, solid, convex, very inequilat-
eral; beaks nearly terminal and apparently full; posterior
ridge widely rounded; anterior end of the shell somewhat

NODULARIA 975

truncated; base line nearly straight; outline of dorsal slope
curved; posterior end somewhat narrowed and almost evenly
rounded; surface covered with a very thick, dark, rather
rough epidermis; teeth strong; pseudocardinals two in each
valve, inclined to be parallel with the large, granular laterals;
beak cavities moderately impressed; muscle scars roughened;
nacre brownish and lead-color, slightly thicker in front.

Length 66, height 36, diam. 22 mm.

Lake Biwe, Japan.

Unio reinianus Koneir, Abh. Senck. Nat. Ges., XI, 1879, p.

424, pl. XXNIM, fig. 1.

Nodularia reiniana Simpson, Syn., 1900, p. 8t0o.—Haas, Con.

Cavs, Unio; 2OrO, p..O7, pl. Xx, fig. 1.

A curious form, but apparently related to U. japanensis.
Since writing the Synopsis I have seen a specimen, in bad con-
dition, which is undoubtedly this species. It came from Lake
Biwe, Japan, and is larger than that measured by Kobelt.
Its form, being somewhat long ovate, its solidity, the heavy
teeth, the pseudocardinals running nearly parallel with the
straight laterals and the brownish and lead-colored, clouded
nacre are good characters.

NopuULARIA UNDULATA Haas.

“Shell rhomboid-elliptical, rather thin and moderately inflat-
ed, rounded in front and nearly vertically truncated behind.
Posterior ridge high, distinctly angulated. Basal margin
straight or slightly curved. Beaks somewhat prominent, situ-
ated at 23/100 of the total length, their sculpture consists of
concentrical, undulated ridges, covering about one-half of
the disk, and running upwards and backwards across the pos-
terior slope. E;pidermis of a yellowish-green, shining. Hinge
consisting of two cardinals and two laterals in the left, one
cardinal and one lateral in the right valve. The cardinals are
solid, lamellated, that of the right valve accompanied by a
very low, lamellar auxiliary tooth. “Laterals long, straight.
Interval short, broad, not distinctly separated from the car-
dinal teeth. Anterior cicatrices distinct, deep; posterior dis-

976 NODUL ARIA

tinct, faint. Dorsal cicatrices united to a groove situated at
the inner side of the interval. Beak cavities shallow. Nacre
silvery, iridescent.
Length 43, height 25, diam. 16 mm.” (Haas).
Type locality, Pisui, Hainan. .
Nodularia undulata Haas, Ann. Mag. Nat. Hist., (8), VI,
1910, p. 497; Con. Cab., Unio, 1910, p. 100, pl. x, figs. 2-3.

Nopul,ARIA PERSCULPTA Haas.

“Shell elongated, low, quite solid. Anterior end very short,
semicircular ; ventral margin horizontal or slightly constricted,
posteriorly bent upwards angularly to the lower angle of the
posterior end; posterior margin first horizontal, then oblique ;
the posterior point is biangulate, the lower angle being more
pronounced than the upper. Beaks anterior, at 19/100 of the
length, very prominent, swollen, their sculpture consisting of
radial wrinkles, of which the central ones unite below forming
a series of successive Vs. Ligament short, weak. Posterior
slope low, distinctly defined. On the posterior ridge is a sys-
tem of wrinkles, which extends in parallel, somewhat wavy
lines both over the posterior slope and the posterior part of
the disk almost to the ventral margin, these parallel lines
meeting on the posterior ridge. In front of the posterior
ridge the lines unite with the aforesaid V-shaped wrinkles ;
the anterior portion of the disk is covered with weaker wrink-
les, which are arranged on the edge of the areola as on the
posterior ridge. This sculpture covers the whole surface in
young shells and nearly all in the adults. Hinge rather weak;
cardinal tooth of the left valve bifid, compressed, with a small
triangular pit, in which arises a small tooth at right angles
to the axis of the shell; cardinal tooth of the right valve tri-
angular, cleft, with a fine vertical slit, in which the lamella
in the pit of the left valve fits; laterals long, thin; one in the
left valve, two in the right valve, a large one and the other
only about half as large, situated at the rear half of the larger
one. Cardinal teeth forming an angle of about 45 degrees
with the axis; laterals parallel with the axis. Anterior muscu-
lar impressions deep, funnel-shaped, posterior shallow. Nacre

NODULARIA 977

bluish-white. Epidermis green or yellow, on the wrinkles
yellowish-brown to brown, eroded on the beaks.
Length 38, height 19.5, diam. 16 mm.” (Haas).
Type locality, Hunan, Central China.
Nodularia persculpta Haas, Nachr. Deutsch. Mal. Ges., 1910,
p. 98; Con. Cab., Unio, 1910, p. 105, pl. x, figs. 4-7. .

Group of Nodularia sagittaria.

Shell elongated, the hinder point above the middle of the
shell, with a sharp posterior ridge and a faint ridge above it;
beaks rather low, their sculpture irregularly radial; disks
finely concentrically striate, not otherwise sculptured; epider-
mis yellowish-olive, cloth-like; pseudocardinals greatly elon-
gated, compressed sometimes dentellate under the beaks; lat-
erals long, compressed. Animal unknown.

NopULARIA SAGITTARTA (Lea).

Shell elongated, subinflated, subsolid, inequilateral; beaks
not greatly elevated; posterior ridge rounded or feebly bian-
gulate, sometimes there are two slightly pinched-up ridges,
ending in a point above the median line; dorsal and ventral
outlines nearly parallel; anterior end rounded, sometimes sub-
angular above; post-basal region but slightly produced, grad-
ually curved up to the much-produced posterior point; surface
with irregular growth lines but not otherwise sculptured; epi-
dermis grayish or yellowish-olive to greenish-olive; teeth
lamellar, rather feeble, the pseudocardinals sometimes slightly
dentellate under the beaks; muscle scars shallow; nacre sil-
very and iridescent.

Length 50, height 18, diam. 14 mm.

Siam ; Cambodia.

Unio sagittarius Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 93;
iss coUN<} Sct veitia.. Uh te57 ps 206, pl. xvi, fier 12 5
Ops; VI, 1857, po £6, pl. xxvii, fie. 12.

Margaron (Unio) sagittarius Lea, Syn., 1870, p. 58.

Nodularia sagittaria Simpson, Syn., 1900, p. 811.

Oxynaia sagittaria Haas, Con. Cab., Unio, 1910, pl. xv, figs.
4-6.

978 NODULARIA

Unio dugasti Morier, Jl. de Conch., XL, 1892, p. 86; XLI,
LSOQ3, P-. 150; Plawa, tigate
Unio jaculus ROCHEBRUNE, Bull. Soc. Phila., 1882, p. 44.
Oxynaia jacula Haas, Con. Cab., Unio, 1910, pl. xv, figs. 5-6.
Remarkable for its greatly alternated pseudocardinals and
laterals and silvery nacre. There are two shells of Unio
dugasti Morlet from the Mekong River, in the National Mu-
seum, which differ from J,ea’s shell only in being smaller, a
little less solid and inflated, and in having a lighter colored
epidermis. I believe them to be the young of N. sagittaria.

Group of Nodularia cerulea.

Shell elliptical, inflated, pointed about on the median line
behind, the post-basal region produced, with a well-developed
posterior ridge; beaks sculptured with numerous fine, radiat-
ing riblets, the central ones of which join below, the whole
often more or less zigzagged and extending well over the
disk ; epidermis generally bluish-green. Animal unknown.

NoODULARIA CERULEA (Lea).

Shell somewhat elongated, subinflated to inflated, inequilat-
eral, rather thin; beaks moderately full, sculptured with radial
ridges, which are somewhat zigzagged; anterior end rounded,
sometimes produced slightly above ; base line straight or lightly
curved, full behind the middle and obliquely truncate behind
to the somewhat produced posterior point ; posterior ridge well
developed; sometimes slightly double, ending in a point about
on the median line; surface with delicate, irregular growth
lines, and often having radiating folds on the posterior slope
and the anterior end; teeth lamellar, delicate, the pseudocar-
dinals somewhat elevated; muscle scars shallow; nacre bril-
liant silvery-bluish, iridescent behind. ‘The exterior of the shell
varies from ashy to bluish-green or nearly blue and is generally
dull.

Length 46, height 22, diam. 17 mm.

Length 4o, height 21, diam. 14 mm.

Length 26, height 13, diam. Io mm.

India; southeast Asia.

NODULARIA 979

Unio ceruleus Lua, Tr. Am. Phil. Soc., IV, 1831, p. 95, pl.
Mii 25 Obs. ,°1834, p.105, pl xii, fig. 25. Haney;
Biv. Shells, 1843, p. 194, pl. xx, fig. 49.—CHENU, III. Conch.,
1858, pl. xvi, figs. 3, 3a, 3b.—Kuster, Conch. Cab. Unio,
1861, p. 228, pl. Lxxvit, fig. 4——Sowsrsy, Conch. Icon.,
XVI, 1866, pl. xt, fig. 230—HaAniey and THEOBALD,
Conch. Ind., 1876, p. 6, pl. x11, figs. 3; 3c:

Margarita (Unio) ceruleus Lea, Syn., 1836, p. 26; 1838, p. 20.

Margaron (Unio) ceruleus LeA, Syn., 1852, p. 30; 1870, p. 47.

Nodularia cerulea Simpson, Syn., 1900, p. STI.

Umo gerbidont Kypoux, Guer. Mag., 1838, p. 9, pl. cxvm,
figs. 2, 2a, 2b.—HANLry, and THEOBALD, Conch. Ind., 1876,
pr Ompl science. 2:

Unio humilis Lwa, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 93;
Ops-WVLeiss7-p, 16, pl. xxvt, figs 16, Ji Ac: N..Sct.’ Phila;
III, 1858, p. 298, pl. xxvi, fig. Io.

Margaron (Unio) humilis Lea, Syn., 1870, p. 32.

Unio corrianus Kuster, Conch. Cab. Unio, 1861, p. 229, pl.
LXVII, fig. 5.

Unio leioma Brnson, Ann. and Mag., 1862, p. 192—HANLEy,
and THEOBALD, Conch. Ind., 1876, p. 6, pl. xu, fig. 6.

Umo pilatus Leaw@ePr Ac. N.Sci. Phila, X, 1866, p. 133; Jil.
mes Ns oct Phila. Vij 186s. p. 281, pl.-xxxvin, fig: 95;
Obs. XT, 1860; p: 47, pl. Xx xvill, fie. O5.

Margaron (Unio) pilatus Lea, Syn., 1870, p. 47.

Unio evitatus Lea, Pr. Ac. N. Sci. Phila., X, 1868, p: 133;
Tie AG oN. cies bhilas) V1, 1868;.p..270, pl: xxxvinl, fig, 92);
Oybs., 2ell, T8609, p- 20;.pl. xxxvi1, fig. 92.

Margaron (Unio) evitatus Lea, Syn., 1870, p. 47.

Unio trirostris Sowrrpy, Conch. Icon., XVI, 1868, pl. Lxv, fig.
331.

Unio andersonianus Nevit1, Jl. As. Soc. Beng., XLVI, 1877,
p. 40; Researches Yun. Exp., 1877, p. goo, pl. Lxxx, figs. 8,
2s

Nodularia andersoniana Preston, Rec. Ind. Mus., VII, 1912,
p. 291.

980 NODULARIA

An abundant, variable species widely distributed through
southeastern sia. I have united a number of nominal species.
not being able to satisfactorily separate them. ‘The species
is usually rather thin or barely subsolid, and more or less
tinted with blue; the surface is almost always dull, the nacre
brilliant and bluish. Unio evitatus of Lea is generally a little
higher and more compressed than the type; U. humilis of Lea
is a small form and might possibly be worthy of varietal rank
if there was not so much intermediate material. Unio ander-
sonianus Nevill is probably a synonym. U. gerbidoni Eydoux
seems from the figure to be a rather solid cerulea.

NopDULARIA SUBSTRIATA (lL,ea).

Shell small, elongated, subinflated, scarcely subsolid, inequi-
lateral; beaks full, rather high, apparently sculptured with a
few irregular nodules: anterior end rounded, subangular
above; base line nearly straight to a decided swelling behind
the middle, obliquely truncated behind the swelling; posterior
ridge somewhat double. ending in a point at or above the
median line; surface ashy-greenish, dull; teeth delicate, lamel-
lar; muscle scars shallow ;-nacre brilliant bluish-silvery, irides-
cent behind.

Length 26, height 13, diam. 9 mm.

Siam.

Unio substriatus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p.

93; Obs., VI, 1857; p.'20, pl: xxva, fig. 14.

Margaron (Unio) substriatus Lea, Syn., 1870, p. 47.
Unio subtriatus Léa, Jl. Ac. N. Sci. Phila., III, 1858, p. 300, pl.

EXVL, hora.

Nodularia cerulea (part) Simpson, Syn., 1900, p. 811.

In the Synopsis I placed this in the synonymy of NV. cerulea,
but the type, the only specimen I have seen, differs in some
minor characters. It is a small shell, though no smaller than
other specimens before me, which I believe are genuine ce-
rulea, and it is possibly a little more elongated than shells of
that species of its size. The beaks are slightly eroded but
their sculpture occupies a less area than in cerulea and appears
to be more granulous or nodular.

NODUTLARIA 981

Ne@DULARIA TERETIUSCULA (Philippi).

Shell elongated, subinflated or inflated, rather solid, inequi-
lateral, with the greatest diameter along and just in front of
the angled posterior ridge; anterior end rounded; base line
nearly straight, full towards the posterior end and obliquely
truncated behind the inflation; posterior point somewhat drawn
out, about midway up from the base; dorsal outline slightly
curved; post-dorsal slope somewhat obliquely truncated ; beaks
moderately elevated, with slightly converging, more or less
zigzag-radial sculpture; surface with irregular growth lines
and sometimes with faint, seminodulous, subplicate sculpture
anteriorly and posteriorly ; epidermis gray-green to blue-green,
generally slightly rayed, dull; left valve with two compressed,
elevated pseudocardinals and two slender laterals; right valve
with one pseudocardinal, often divided and one lateral; ante-
rior scars impressed; nacre bluish, slightly iridescent.

Length 50, height 20, diam. 16 mm.

Upper Nile drainage.

Unio teretiusculus Puitippi, Conch., III, 1847, p. 45, pl. m1.
fig. 3—?Kuster, Conch. Cab., 1856, p. 133, pl. xxxv, fig. 5.
—Sowerpy, Conch. Icon., XVI, 1868, pl. Lxxv, fig. 389.—
jieKecy Faun, gO. Af., 1874,.p. 276, pl. X1, figs. 1,-2.

Nodularia teretiuscula Simpson, Syn., 1900, p. 812.

Margarita (Umio) cailliaudi Lea, Syn., 1838, p. 24.

Margaron (Unio) cailliaudi Lea, Syn., 1852, p. 36; 1870, p. 58.
Although this is an African species, it appears to be very

closely related to N. c@rulea, which is confined to southeast

Asia. It is a little more elongated than that species, is more

solid, is usually somewhat rayed, while cerulea is rayless or

almost so, and it has duller nacre.

Var. lithophaga “Ziegler” Pallary.

‘Differs from the type figured by Philippi by its smaller
size, its beaks nearer the posterior margin and more elongated
anterior end.” (Pallary).

Type locality, the White Nile.

Unio lithophagus ZiecLeR, manuscript, probably.

982 NODUL ARIA

Nodularia (Lanceolaria) teretiusculus var. lithophaga “Zi%c-
LER’ PaLLAry, Mem. Inst. Egypt., VI, 1909, p. 79.
Nodularia terctiuscula (part), Simpson, Syn., 1900, p. 812.

NOpDULARIA LEDCULXIANA (Charmes).
Central Africa.
The description of this species is not accessible to me, and

I have never seen an authentic specimen. von Martens places

it in the group of Unio teretiusculus. It has never been figured

so far as I know.

Unio ledoulxianus CHARMES, Bull. Soc. Mal. Fr, IT, 1885, p.
173.—BourcuiIcnat, Moll. Af. Eq., 1889, p. 194.—voN
Martens, Besch., 1897, p. 220. .

Nodularia ledoulxiana Stmpson, Syn., 1900, p. 812.

NODULARIA GAUDICHAUDI (Eydoux).

Shell irregularly subelliptical, slightly narrower in front,
apparently rather solid, inequilateral, convex ; beaks moderate-
ly elevated, slightly sculptured; posterior ridge well develop-
ed, narrowly rounded, ending behind in a blunt point about
on the median line; anterior end rounded; base line straight,
but very full behind the middle and obliquely truncated behind
this point; dorsal line nearly straight; dorsal slope obliquely
truncate; epidermis dirty greenish with brown, concentric
bands; muscle scars well marked; nacre rose-purple.

Iength 40, height 22, diam. 15 mm.

Small streams of Bengal.

Unio gaudichaudi Eypoux, Guer. Mag., 1838, p. 10, pl. cxvim,

SS.

Margaron (Unio) gaudichaudi Lea, Syn., 1850, p. 32; 1870,
p50:

Nodularia gaudichaudi Stimpson, Syn., 1900, p. 812.

Nodularia cerulea var. gaudichaudii Preston, Rec. Ind. Mus.,

Vil. 1912 pa2se,

There are some slight discrepancies between the descrip-
tion and the well-executed, colored figure of this species. The
latter shows the shell to be somewhat solid, with brownish,

NODULARIA 983

concentric bands; in the description the shell is said to be thin
and no mention is made of the color bands. It is a shorter
shell than ceriulea and differs in the color of its nacre.

NODULARIA KERAUDRENI (Eydoux).

Shell subovate, subinflated, inequilateral; beaks rather full;
anterior end narrowed; base line curved, full behind the mid-
dle, curving from the swelling to the blunt posterior end;
dorsal slope subtruncate ; posterior ridge not strongly develop-
ed, apparently somewhat double; epidermis brownish or
brownish-green; pseudocardinals somewhat compressed, rag-
ged; laterals delicate, curved; anterior scars well marked,
posterior scars shallow ; nacre yellowish-white.

Length 41, height 22, diam. I5 mm.

Rivers and swamps of Bengal.

Unio keraudreni Kypoux, Guer. Mag., 1838, p. 8, pl. cxvut,
figs. I, Ia.
Margaron (Unio) keraudreni Lua, Syn., 1852, p. 30; 1870, p.

46.

Nodularia keraudrenit Simpson, Syn., 1900, p. 812.
Nodularia cerulea var. keraudrent Preston, Rec. Ind. Mus.,

VII, 1912, p. 289.

This shell is somewhat obovate, and the outlines are much
less angular than they are in cerulea and other related forms.

NopULARIA SHURTLEFFIANA (Lea).

Shell somewhat elongated, inflated, rather solid, inequi-
lateral ; beaks full and high, sculptured with a great number of
fine, radiating, somewhat zigzag ridges, which extend well
on to the disk; anterior end rounded; base line straight or
lightly curved, rather full behind the middle; posterior ridge
full, somewhat double, ending in a feeble biangulation at and
below the median line; surface delicately, concentrically, sub-
granulously ridged, and having more or less fine, subradial,
corrugated sculpture; epidermis tawny to greenish, the green
predominating behind, slightly rayed, and having two or
three broad green rays on the dorsal slope; pseudocardinals

984 NODULARIA

subcompressed, somewhat irregular; laterals delicate; ante-

rior scars impressed; nacre silvery-white, thinner behind.
Length 57, height 27, diam. 21 mm.

India; Siam.

Umio shurilefianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p-
o4? Obsi; VI-1857,. p22) pk ey ene 7s Ae en oe
Phila., TT, 1858;p;'302; pl. xxvii, 17;

Margaron (Unio) shurtlefianus Lea, Syn., 1870, p. 32.

Nodularia shurtleffiana SIMPSON, Syn., 1900, p. 813.

A larger species than cerulea, biangulate, and not so point-
ed behind. The color of the epidermis is different and the
surface is sculptured to a greater extent.

NODULARIA ANCEPS (Deshayes).

Shell irregularly long elliptical, subsolid, convex, inequi-
lateral; beaks neither very full or high, sculptured with fine,
radial ridges, some of which are zigzagged and extending
well on to the disk; the sculpture gradually changes to fine
nodulous corrugations and fades out on the border of old
shells: posterior ridge well developed, having a tendency to
be narrowly double, ending behind in a point or slight bian-
gulation at or below the median line; anterior end rounded ;
base line straight or lightly curved, full behind the middle;
hinge line lightly curved; dorsal slope obliquely truncated ;
surface and epidermis roughened, scarcely shining, ashy, yel-
lowish-green or greenish, frequently banded with yellowish
and darker behind, where it is sometimes faintly rayed; hinge
teeth subsolid; pseudocardinals rather short; anterior scars
well impressed ; nacre white or flesh-colored, brilliant.

Length 43, height 24, diam. 14 mm.

Cambodia.

Unio anceps Desuayes, Nouv. Arch. de Mus., X, 1874, p. 127,.

pl. vi, figs. 8-12.

Nodularia anceps SIMPSON, Syn., 1900, p. 814.
Oxynaia anceps Haas, Con. Cab., Unio, 1910, pl. xiv, figs. 1-3.

Dr. Lea has a number of specimens which he has called
U. shurtlefhanus, which I am satisfied are not that species, but

NODULARIA 985

are Deshayes’ U. anceps. The type of the former is not in his
collection, but there are two authentic, larger specimens. These
are much more inflated, are more elongated than anceps, and
have three distinct posterior rays. ‘They are on the whole,
less strongly sculptured than anceps. While it is possible that
the two may run together, [ am inclined to believe them dis-
tinct.

NODULARIA occaTA (Lea).

Shell subrhomboid, subcompressed, inequilateral, rather sol-
id; beaks low and subcompressed, their sculpture consisting
of radial and somewhat zigzag ridges, this sculpture extending
over the whole shell and becoming somewhat granulous; an-
terior end rounded; base line curved, slightly fuller near the
posterior end; posterior ridge well developed, ending in a
blunt point below the median line; dorsal slope obliquely,
strongly truncate; surface covered with granular, concentric
sculpture; epidermis dirty greenish, dull; pseudocardinals
rather solid; laterals curved; anterior scars well impressed ;
posterior scars shallow; nacre bluish-white, flesh-colored in
the cavities, iridescent.

Length 36, height 20, diam. 11 mm.

India.

Unio occatus, Lea, Pr. Ac. N. Sci. Phila., 1V, 1860, p. 307;
jl. Ac. N. Sci. Phila.; VI, 1863, p. 398, pl. 1, fig. 304; Obs.,
X, 1863, p. 34, pl. L, fig. 304.—Sowersy, Conch. Icon., XVI,
1868, pl. LXxIXx, fig. 412.

Margaron (Unio) occatus Lea, Syn., 1870, p. 31.

Nodularia occata SIMPSON, Syn., 1900, p. 813.

Unio macilentus BENSON, Ann. and Mag., X, 1862, p. 187.—
Hantey, and THroparp, Conch. Ind., 1876, p. 5, pl. x, figs.
2, ASD. O62, DIL ICLIV, figs 5.

Unio rugesus HANtEY and THrKoBaLp, Conch. Ind., 1876, p.
62 pl. CLIV, Hees.

More compressed than any of the allied species. It is a com-
paratively short, rhomboid form, covered throughout with
granular concentric ridges and traces of zigzag sculpture.

986 NODULARIA

NoODULARIA MOSSAMBICENSIS (von Martens).

Shell subrhomboid, subsolid, inequilateral, somewhat inflat-
ed; beaks moderately full; anterior end rounded; base line
curved, not very full behind the middle; dorsal outline lightly
curved; dorsal slope obliquely subtruncated; posterior ridge
low, rounded, ending in a rounded point below the median line ;
surface strongly concentrically striate; epidermis olivaceous ;
pseudocardinals subcompressed, triangular, sulcate; macre
pearly.

Length 41, height 24, diam. 17 mm.

Sennaar, northeast Africa; Mosambique, Zambezi River.
Unio mossambicensis von Marrens (Peter’s manuscript),

Mal. BL, Vi, 1860, p. 218) pl. wi.tigs. 3-55 Besch. Deuts.

Ost. Af:, 1807,-p. 225, pla vu, he. 2:

Nodularia mossambicensis SIMPSON, Syn., 1900, p. 813.
Cafferia mossambicensis ConNoLLy, Ann. S. A. Mus., XI,

1Q12, "p. 273.

Unio sennariensis var. von Martens, Mal. BL, XXI, 1873,

Pp. 43.

Unio parreysi (v. d. Busch.) var. schweinfurtlt voN MARTENS,

Noy. Conch., 1V, 1876, p. 140, pl. cxxxm, figs. 4-5:

I cannot be positive as to the relationship of this species,
which I have never seen. The outline is subrhomboid, and
in the specimen figured a very little cut away at the antertor
base.

NoDULARIA INORNATA (Lea).

Shell somewhat elongated, slightly obovate, thin, convex,
inequilateral; beaks full and high; posterior ridge rounded,
ending in a blunt point about on the median line; dorsal line
lightly curved; anterior end rounded; base line rounded or
nearly straight, fuli behind the middle; dorsal slope somewhat
obliquely truncated; surface nearly smooth; epidermis dirty
bluish-green or yellowish-green, dull, having two or more
faint, posterior rays; teeth greatly compressed, attenuated ;
muscle scars shallow, faint; nacre bluish-silvery, iridescent.

Length 45, height 23, diam. 16 mm.

Siam ; Cambodia.

NODULARIA 987

Unio mornatus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p.-93;
Obs:, VI, 1857, p13; pl. xxiv, fig. 6; Jl. Ac: N. Sci. Phila.,
PE aie ep: 2024 ply KTV ei k6:

Margaron (Unio) tmornatus Lea, Syn., 1870, p. 47.

Nodularia inornata Simpson, Syn., 1900, p. 813.

Physunio imornatus Haas, Conch. Cab., Unio, 1912, pl. 34
figs. 3-4.

Much thinner than cerulea, to which it seems closely related,
and not so pointed nor angulated behind. ‘The beak sculpture
appears to be zigzag radial, but the beaks are too badly
eroded in all the specimens seen to allow: of any definite con-
clusion.

>

NopulLARIA PACHYSOMA (Benson).

Shell somewhat elongated, inflated, rather solid, inequilat-
eral; beaks full and high, their sculpture zigzag radial, not ex-
tending over the disk; posterior ridge strong, apparently in-
clined to be double, curved down in the middle, ending behind
in a blunt point on the median line; anterior end rounded,
subangulate above; base line lightly curved, quite full behind
the middle; dorsal slope decidedly and obliquely truncate;
surface apparently nearly smooth; epidermis bright green with
faint, yellowish bands, with two or more dark green, posterior
rays; hinge line nearly straight; teeth somewhat strong; lat-
erals straight ; nacre pinkish.

Length 45, height 22, diam. 20 mm.

Assam.

Unio pachysoma Brnson, Ann. and Mag., X, 1862, p. 186.—
Haniey and THEOBALD, Conch. Ind., 1876, p. 6, pl. x1,
Moir:

Margaron (Unio) pachysoma Lea, Syn., 1870, p. 63.

Nodularia pachysoma Simpson, Syn., 1900, p. 813.

Unio pachystema Payret, Conch. Sam., III, 1890, p. 162.

This species is smoother and much more inflated than
cerulea, to which it is evidently nearly related, and it seems
to be solider and brighter. The above description is drawn
from the figures of this species in the Conchologia Indica,
these figures being made from the type.

9388 NODULARTA

NoepuLARIA CHAUDHURII Preston.

“Shell small, rather thin, elongately ovate, pale olive, covered
with a finely laminiferous periostracum; both valves concen-
trically striate, sculptured with irregular, minute, nodulous,
radiate ridges, which appear posteriorly as regular corruga-
tions; umbones small, somewhat prominent; dorsal margin
slightly arched; ventral margin straight; anterior side pro-
duced, rounded; posterior side bluntly rostrate, abruptly slop-
ing above and below; hinge-teeth elongate, anteriorly project-
ing; anterior scars deep, roundly triangular; posterior scars
scarcely impressed; interior of shell iridescent, nacreous, pos-
teriorly corrugate.

Long. 12.75, lat. 23 mm.” (Preston).

Type locality, Upper Burma.

Nodularia (Nodularia) chaudhurti Preston, Rec. Ind. Mus.,

Wil 1912) p.-200:

NopULARIA BONNEAUDI (Eydoux).

Shell irregularly subrhomboid, much inflated, being decided-
ly fullest in the middle, inequilateral, rather thin; beaks full
and high; dorsal outline curved; anterior end narrowed, more
full above; base line nearly straight to a remarkable swelling
behind the middle, and rounded from the swelling to the
hinder end; posterior ridge well developed, subangular, end-
ing in a rounded point a little below the median line; dorsal
slope decidedly and obliquely truncate; surface with fine,
wrinkled sculpture, especially on the dorsal slope ; epidermis
greenish, lightly banded with brownish; laterals delicate,
curved; nacre bluish-white, brilliant.

Length 43, height 24, diam. 19 mm.

India.

Unio bonneaudi Eypoux, Guer. Mag., 1838, p. 10, pl. cxrx,
figs. 1, ta—Sowerpy, Conch. Icon., XVI, 1868, pl. xcv, fig.
sts.—Hantxy and THroparp, Conch. Ind., 1876, p. 5, plex
fig. 6.—ANpERsoN, Yunnun Exp., 1878, p. 900, pl. LXxx,

figs. 8-12.

NODULARIA 989

Margaron (Unio) bonneaudi Lea, Syn., 1852, p. 32; 1870, p.

50.

Nodularia bonneaudi Simpson, Syn., 1900, p. 813.

More rhomboid than N. cerulea or any of the nearly allied
forms, and decidedly inflated. Looking at the shell from
above, its greatest diameter is at the middle, decreasing very
suddenly toward each end. According to Eydoux the beaks
are not roughened.

NODULARIA ASPERULA (Lea).

Shell somewhat obovate, convex or subinflated, thin, inequi-
lateral; beaks high and full; posterior ridge full, narrowly
double, ending in a narrow biangulation about on the median
line; anterior end rounded, angular above; base line lightly
curved, quite full behind the middle; hinge line curved; dor-
sal slope decidedly obliquely truncated; surface with faint,
nodulous corrugations or almost smooth ; epidermis yellowish-
green, sometimes having feeble, yellowish bands, with two or
three dark green rays on the posterior end, shining; teeth
very much compressed; pseudocardinals well developed; lat-
erals curved; muscle scars shallow; nacre bluish, brilliant and
silvery.

Length 43, height 24, diam. 16 mm.

Siam; Cambodia.

Unio inornatus Reeve, Conch. Icon., XVI, 1865, pl. Xx1x, fig.
147.

Unio asperulus Vea, Pr. Ac. N. Sci. Phila., X, 1866, p. 133;
jl. Ac. N. Sci. Phila., VI, 1868, p. 280, pl. xxxvui1, fig. 94;
Obs., XII, 1869, p. 40, pl. xxxvui1, fig. 94.

Margaron (Unio) asperulus Lua, Syn., 1870, p. 31.

Nodularia asperula SIMPSON, Syn., 1900, p. 814.

Oxynaia asperula Haas, Con. Cab., Unio, 1910, pl. xiv, fig. 5.

Margaron (Unio) versus Les, Syn., 1870, p. 46.

This species combines characters of the cerulea and contra-
dens groups. The younger shells, which I have seen, would in-
dicate close relationship to the former assemblage; adult
specimens have characters of the latter. The species is not so
elongated as cerulea or inornata and is more polished.

990 NODULARIA

NoOpULARIA PUGIO (Benson).

Shell irregularly long ovate, subsolid to solid, subinflated,
inequilateral; beaks somewhat elevated but not very Tall:
posterior ridge strong, sharply angled, nearly straight or light-
ly curved, ending in a decided, rather prolonged point at or
below the median line; anterior end rounded; base line nearly
straight, inflated behind the middle and ending behind in a
long, oblique, truncation; hinge line decidedly curved behind
the pseudocardinals ; dorsal slope having a long, oblique trun-
cation; surface irregularly striate; posterior slope often pli-
cate; epidermis yellowish, tawny or greenish, often banded,
subshining ; pseudocardinals subcompressed, ragged; laterals
remote; muscle scars impressed; nacre dirty flesh-color.

Length 60, height 30, diam. 20 mm.

Burma.

Unio pugio Benson, Ann. and Mag., X, 1862, p. 193—SOWER-

By. Conch: Icons XVI, 18664 ple xev, Hows 16.

Nodularia pugio Simpson, Syn., 1900, p. 814.
Oxynaia pugio Haass, Con. Cab., Unio, 1910, pl. xiv, figs. 6-7.

Sowerby’s figure represents a young specimen. The color
of this species is quite variable, some specimens being almost
clear green, others olive-green, while still others are tawny,
but all that I have seen are banded. The high, sharp posterior
ridge and long, sharp posterior point are good distinguishing
characters.

NoODULARIA MICHELOTI (Morlet).

Shell subovate, solid, inflated, inequilateral, somewhat nar-
rowed and rounded in front; base line lightly curved, full
and rounded behind the middle; dorsal outline almost evenly
curved; posterior ridge rather high, subangulate, placed close
to the dorsal margin and parallel with it, ending in a blunt
point above the median line; surface sculptured with irregu-
lar strize; epidermis olive-green and black; pseudocardinals
somewhat solid; laterals strong, nearly straight; anterior
scars deep; posterior scars shallow ; nacre straw-colored.

Length 38, height 21, diam. 15 mm.

Tonkin.

NODULARIA 991

Unio micheloti More, Jl. de Conch., XXXIV, 1886, pp. 77,
291, pl. x11, figs. 6, 6a.

Nodularia micheloti Simpson, Syn., 1900, p. 814.

Oxynaia micheloti Haas, Con. Cab., Unio, 1910, pl. xiv, fig.
8-9; (“O. hedeja MaBiLie”’), ibid, pl. xv, figs. 1-2.

A rather small, solid, inflated, somewhat obovate species,
which would seem from the figure to be closely related to N.
pugio.

NoDULARIA GLADIATOR (Ancey).

Type locality, Tonkin.

Unio gladiator Ancry, Le Nat., II], 1881, p. 468.—Simpson,
Syn., 1900, p. 862.—DaAutzEenBuRG and H. Fiscuerr, Jl. de
Conch: LITI»1roa5; ps 206.

The description of this species is not now accessible to me.
Dautzenburg and Fischer, (1. c.), state that in their opinion
the name will have to be dropped, as owing to the lack of a
figure and a sufficient description, it is impossible to determine
whether Ancey referred to N. jowrdyi or N. micheloti.

NopULARIA FLUCTIGERA (Lea).

Shell somewhat elongated, subrhomboid, scarcely subsolid,
convex, inequilateral, a little narrower in front, the anterior
end being cut away below and narrowly rounded; base line
straight or lightly incurved to behind the middle where it is
full; dorsal outline curved a little; dorsal! slope obliquely trun-
cate behind; posterior ridge subangular, ending in a blunt
point below the median line; beaks moderately full, but little
elevated, sculptured with strong, oblique ridges, which are
somewhat zigzagged and continued over the whole surface;
in addition to this the growth lines are raised into numerous,
distinct threads, causing the shell to appear somewhat unevenly
reticulate ; epidermis dull brownish-green or olive-green; teeth
delicate, sublamellar; dorsal scars strong; muscle scars shal-
low; nacre bluish, iridescent, and in the examples seen, show-
ing something of the external sculpture.

Length 48, height 21, diam. 14 mm.

Southeast Asia, no doubt.

992 NODUL,ARIA

Unio fluctiger Lua, Pr. Ac. N. Sci. Phila., III, 1850, p. 152;
Ji. Ac. N. Sc1.;Phila., DV 51860; "p. 250,-ple xx xix ne 30,
Obs., VII, 1860, p. 68, pl. Xxx1x, fig. 130.—Kustrr, Conch.
Cab. Unio, 1861, p. 237, pl. LxxXx, fig. 1—Sowerrsy, Conch.
Icon., XVI, 1866, pl. x11, fig. 299.

Margaron (Unio) fluctiger Liza, Syn., 1870, p. 32.

Nodularia fluctiger Stmpson, Syn., 1900, p. 814.

Nodularia fluctigera Haas, Con. Cab., Unio, 1910, p. 107, pl.
x) fies S.

In the description of this species Dr. Lea states that it be-
longs in the Cabinet of Mr. Cuming, and no locality is given.
Two shells, which are labeled Unio fluctiger, are in his col-
lection and seem to be genuine. These are said to come from
the Yuruari River, British Guiana, received from R. P. Stev-
ens. While this may be true, I am inclined to believe that
there is some mistake about the locality, and that these shells
came from Southeast Asia. The species is sculptured through-
out with oblique, subradial ridges and in Lea’s shells this sculp-
ture is most decidedly zigzag. ‘This is a character not found
in any South American species, so far as I know, but it is
very common in the shells of the Oriental region.

NODULARIA SCOBINATA (Lea).

Shell small, somewhat elongated, convex inequilateral, sub-
solid ; beaks only moderately full and high, their sculpture con-
sisting of strong, zigzag-radial ridges, which extend over the
entire surface; posterior ridge subangular, ending in a point
on the median line; dorsal outline almost evenly curved; ante-
rior end rounded; base line a little incurved, but becoming: full
behind, then obliquely truncated to the posterior point; in front
of the posterior ridge there is a wide, radial inflation and in
front of this a median depression; epidermis greenish, the
ridges upon it bright green; pseudocardinals subcompressed ;
laterals curved; anterior scars impressed ; nacre silvery, irides-
cent.

Length 34, height 15, diam. 11 mm.

Siam ; Cochin-China ; Cambodia.

NODULARIA 993

Unio scobinatus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 93;
Ons V1. I8s7.0. 19, plaxeva, dias > JiAc.N. Sei, Philas
IIT, 1858, p. 299, p!. xxv1, fig. 13.—Sowersy, Conch. Icon.,
XVI, 1868, pl. uxru, fig: 313—Morerer, Ser. Conch., IV,
1875, p. 354, pl. xvu, figs. 2-6.

Margaron (Unio) scobinatus Lea, Syn., 1870, p. 32.

Nedularia scobinata SIMPSON, Syn., 1900, p. 815.—Haas, Con.
Cab. Unio, 1910; p. 100, pl. x, figs. g-11.

Unio mandarinus More et, Jl. de Conch., XII, 1863, p. 159.

Unio pellis-lacerti Morrier, Jl. de Conch., XIII, 1865, p. 22.—
Sowersy, Conch. Icon., XVI, 1868, pl. Lxxxvi, fig. 457.—
Moretet, Ser. Conch., IV, 1875, p. 355, pl. xvu, fig. 5.

Unio venustus Morevrt, Jl. de Conch., XIV, 1866, p. 63.

Unio oblitus Lea, Syn., 1870, p. 64.

At first sight this seems to be only a form of Gould’s Unio
crispata, but a careful examination shows that there appears
to be differential characters as Dr. Lea has pointed out. It is
rather more elongated than crispata and has a median radial
depression not found in that. The nacre is brighter than in
Gould’s shell and it is less inflated.

For this species and N. fersculpta Haas, fluctigera Lea,
phaselus Lea and nucleus Lea, Haas, (Conch. Cab., Unio,
IQI2, p. 105), has made a new section, Scabies.

NopULARIA DIESPITER ( Mabille).
Type locality, Tonkin.
Unio diespiter Maviiie, Bull. Soc. Mal. Fr., IV, oe p. 162.
—SIMpson, Syn., 1900, p. 861.
Oxynaia diespiter Haas, Con. Cab., Unio, 1910, al Va! es 3.
The description of this species is not now accessible to me.
Haas, (1. c.), figures it and refers it to his new genus O-rynaia,
but has not yet described it in his new monograph.

NopuLARIA GRATIOSA (Philippi).

Shell small, much compressed, somewhat elongated, appar-
ently subsolid ; beaks neither full nor high; posterior ridge well
developed, ending behind in a point on the median line; ante-

994 NODULARIA

rior end narrowed and rounded; base line straight to behind
the middle, where it is very full, behind this swelling the base
is obliquely truncated; dorsal line lightly curved; dorsal slope
decidedly and obliquely truncated; surface covered with zig-
zag-radial sculpture, dirty yellowish or greenish; pseudocar-
dinals compressed, triangular ; nacre salmon-tinted.

NTength 22, height 13, diam. 6 mm.

Southeast Asia, no doubt.

Unio gratiosus Puiiippt, Conch., I, 1845, p. 20, pl. 1, fig. 5.—

?Kuster, Conch. Cab., Unio, 1861, p. 239, pl. Lxxx, fig. 3.
Margaron (Unio) gratiosus LEA, Syn., 1870, p. 32.
Nodularia gratiosa SIMPSON, Syn., 1900, p. 815.

A very dubious species, the figure probably representing a
young shell. I am very strongly inclined to believe that Des-
hayes’ Unio anceps is the adult form of this species, Philippi’s
figure representing a young, rather compressed form. Philip-
pi’s locality, New Holland, is evidently erroneous.

NopULARIA CRISPATA (Gould).

Shell rather solid, inflated or subinflated, ovate or irregularly
elliptical; beaks rather full and high, having zigzag-radial
sculpture, which extends over the surface of the shell; dorsal
outline curved ; anterior end rounded; base line lightly curved,
full behind the middle; posterior ridge strong, sometimes
slightly double, angled, ending in a point at or below the
median line; surface dull greenish, the ridges darker ; pseudo-
cardinals subcompressed to subsolid, ragged; laterals curved;
muscle scars impressed ; nacre whitish to dirty flesh-colored.

Length 1.7, height .9, diam. .5 in.

British Burma.

Unio crispata Goutp, Pr. Bost. Soc. Nat. Hist., I, 1843, p. 141.
Unio crispatus Haney and THropaip, Conch. Ind., 1876, p.

21, pl. xiv, fig. 1.—von Marrens, Arch. Naturg, LXV,

T8990, p. 42, pl. v, fig. 3.

Margaron (Unio) crispatus Lea, Syn., 1870, p. 32.
Nodularia crispata Stpson, Syn., 1900, p. 815.

NODULARIA 995

Generally solider'and more inflated than scobinata, and lack-
ing the median depression seen in the shell of that species.
The nacre is less brilliant and the muscle scars more impress-
ed; the pseudocardinals are usually stronger. Yet there are
intermediate specimens. which nearly connect the two.

NopULARIA NUCLEUS (Lea).

Shell very small, solid, inflated, subquadrate or subrhomboid,
inequilateral; beaks full and high, with strong, zigzag-radial
sculpture, which extends over the shell; dorsal outline curved ;
anterior end slightly narrowed, rounded; base line lightly
curved, rather full behind the middle; posterior ridge high,
subangular, ending near the base of the shell; posterior end
obliquely rounded, almost truncate below; epidermis pale
green, the ridges rich green; pseudocardinals much divided;
laterals curved, strong; anterior scars deep; posterior scars
shallow ; nacre very brilliant, silvery, iridescent behind.

Length 15, height 9, diam. 8 mm.

Siam.

Umornucleus na, Pr: Ac.. N. Sci; Phila., VIII, 1856; p:. 04;
Ops. Vv isiss ap: 20, pls xxvii, ie 21 ; Jl. Ac. N. Sci: Phila.,
PLE 1S58;po 302, pl. xxvinw fig at:

Margaron (Unio) nucleus Lea, Syn., 1870, p. 30.

Nodularia nucleus Stmpson, Syn., 1900, p. 815.—HAas, Con.
Cab mio. TOTO, ps 113, ply x; fig. 13.

If the only shell I have seen, the type, is adult, this is the
smallest naiad I know of. The type is solid and much inflated,
and has the appearance of being mature. It is shorter, more
inflated, solider and more quadrate than crispata and has much
brighter nacre.

NopULARIA PHASELUS (Lea).

Shell small, elongated, subsolid, inflated, inequilateral ; beaks
rather full and high, their sculpture apparently zigzag-radial ;
anterior end rounded and slightly narrowed; base line nearly
straight, full near the hinder end; posterior ridge full, rounded,
end in a blunt point on the median line; surface nearly smooth,
slightly corrugated on the umbonal region and dorsal slope;

996 . NODULARIA

epidermis greenish straw-colored, with narrow, broken, green

bands and zigzag, green markings, very smooth and shining;

teeth compressed; beak cavities rather deep; anterior scars
impressed ; nacre bluish-white, silvery.

Length 27, height 13, diam. 11 mm.

Siam.

Unio phaselus Lea, Pr..Ac. N. Sci. Phila., VIII, 1856, p. 94;
Obs; VI; 1857) px 17) pl. xx fig. 11; Ja Ae Ne Sel. ila:
IIT, 1858, p.207, pl. xxvi, fig. Tr.

Margaron (Unio) phaselus Lea, Syn., 1870, p. 32.

Nodularia phaselus Stimpson, Syn., 1900, p. 815.—HAaas, Con.
Cab.,-Wnio; 1910; po Lily ph «xs fe ie,

I have seen but a single shell of this species, the type, and
it seems nearly related to NV. crispata. Its smooth surface and
shining, greenish-yellow epidermis, marked with rich green,
distinguish it from any allied species.

NopuLAria ScoBina (Hanley).

Shell decidedly rhomboid, subcompressed, rather solid, in-
equilateral ; beaks only moderately full or high; posterior ridge
well developed, sometimes slightly double, ending in a point
or faint biangulation near the base of the shell; anterior end
rounded; base line nearly straight, slightly incurved in the
middle, a little inflated near the posterior end; dorsal slope
obliquely subtruncate; surface covered with raised, more or
less broken, subradial, somewhat zigzag corrugations, in some
places resembling a worn rasp; epidermis greenish, with a dark
green ray on the dorsal slope; pseudocardinals somewhat
rudimentary ; nacre bluish, iridescent behind.

Length 32, height 17 mm.

Assam.

Unio scobina Han ey, Biv. Shells, 1856, p. 382, pl. xx, fig.
40.—HAnN try and Turorayp, Conch. Ind., 1876, p. 22, pl.
XLVil, des. ae

Nodularia scobina Simpson, Syn., 1900, p. 816.

The shell of this species, according to the figures and de-
scription, is shaped a good deal like that of N. fluctigera, but is
more solid, has more broken sculpture and is not so elongated.
According to Hanley and Theobald it is very rare.

NODULARIA 997

Group of Nodularia pazit.

Shell thin, with the hinder point long drawn out, posterior
ridge double, low, and sharp, the dorsal line above this straight
or incurved; beak sculpture not seen; surface of the shell
smooth, dull olive-colored; teeth exceedingly compressed ;
pseudocardinals long, lamellar.

NopurlARIA PAZII (Lea).

Shell irregularly long ovate, inflated, rather thin, inequilat-
eral; beaks full and high, with a narrow, well-marked lunule
in front of them; posterior ridge low, very close to the dorsal
margin, angled above, with the outline of the dorsal slope
curved downward a little in the middle, ending about on the
median line in a long, slightly up-curved beak; anterior end
rounded; base lightly curved, slightly prominent behind the
middle, behind the prominence obliquely truncated; surface
with delicate, irregular growth lines; epidermis dirty olive
with lighter bands, silky ; teeth lamellar, there being one greatly
compressed pseudocardinal and two laterals in the left valve,
and two pseudocardinais and one lateral in the right; beak
cavities excavated ; muscle scars shallow; nacre bluish, faintly
iridescent behind.

Length 64, height 29, diam. 22 mm.

China; Siam; Cambodia.

Unio pazii Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 176; Jl. Ac.
N. Sci. Phila., VI, 1866, p. 61; pl. xxi, fig: 60; Obs., XI,
1867, p. 65, pl. xx1, fig. 60—Sowersy, Conch. Icon., XVI,
1868, pl. xcrt, fig. 502.

Margaron (Unio) pazii Lea, Syn., 1870, p. 39.

Nodularia pazit Simpson, Syn., 1900, p. 816.

Oxynaia pazii, Haas, Con. Cab., Unio, 1910, pl. xiv, figs. 10-
Lic .

A most striking and attractive species. When fresh the
epidermis is rather dull and silky but when it is worn it be-
comes smooth and somewhat shining and exhibits faint traces
of rays. I know of no species in which the teeth are more
compressed.

998 NODULARIA

For this group Frierson has recently proposed the new
generic name of EnsipeNns, (Naut., XXIV, 1911, p. 98). He
says:

“The Unio ingallsiana I,ea differs generically from Nod-
ularia in having little or no beak sculpturing and in having a
smooth shell. Its cardinal teeth are blade-like and double in
the right valve and single in the left. The cardinal teeth form
a part of the general inner part of the shell, not having a
“fulcrum” (as the buttress-like thickening of the noose sup-
porting the cardinal teeth, and extending posteriorly to the
adductor scar, may be called), which is so generally shown in
most Unionide. ‘The “third anterior muscular scar” is sepa-
rate from the anterior adductor scar, whereas in Nodularia
they are always confluent and not easy to differentiate. For
those shells, as the Unio pas Lea (and imgallsiana Lea), ex-
hibiting these characters as outlined, the writer proposes the
new genus EnsipENs. ‘Two other peculiarities of the two
species named may prove to be of generic significance, but at
present they may be regarded as being of specific import mere-
ly. These are the entire confluence of the anterior adductor
and the ‘‘protractor pedis” muscle scar, and that the escutcheon
is half way the length of the lateral teeth.”

NODULARIA youRDYI ( Morlet).

Shell somewhat elongated, solid, greatly inflated, inequilat-
eral; beaks full and high, with undulated sculpture; posterior
ridge not greatly elevated but decidedly angled, curved slight-
ly downward in the middle; anterior end rounded, somewhat
angled above; base line curved, fuller behind the middle with
a long, sloping truncation at the posterior end; posterior point
above the median line; surface lightly striate; epidermis
brownish-green; pseudocardinals subsolid, somewhat com-
pressed; laterals lightly curved; anterior scars deep; posterior
-scars shallow ; nacre white.

Length 50, height 24, diam. 22 mm.

Tonkin.

NODULARIA 999

Unio jourdyi Morir, Jl. de Conch., XXXIV, 1886, pp. 76,
289, pl. xIII, figs. 5, 5a.

Nodularia jourdyi SIMPSON, Syn., 1900, p. 816.

O.rynaia jourdyvi Haas, Con. Cab., Unio, 1910, pl. xvi, figs.

2

Var. corrugata (Dautzenburg and H. Fischer).
“In this variety the tuberculous sculpture of the beaks ex-
tends down over part of the disk.” (D. & F.)
Unio jourdyi var. corrugata DAutzENBuURG and H. Fiscuer,
ji.de Conch,;-LEIIL, 1905). p: 205.

Var. ponderosa {Dautzenburg and H. Fischer).

This variety differs from typical U. jourdyi by its much
thicker shell, its higher and much more inflated anterior re-
gion and its more prominent beaks.” (D. & F.)

Type locality, Grand ac, Hanoi.

Unio jourdyi var. ponderosa DAUTZENBURG and H. FIscHEr,

jide Conch. LIM, 16055 p:.453.

Jn the synopsis | placed this species in the pasii group, but
it is probable that it should go in the group of \. cerulea.
While its external appearance is something like that of N.
pazu, the pseudocardinals are much shorter and stronger. It
seems to stand between the two groups. The shell is more
inflated behind the middle than N. pazit.

Haas has recently, (Nachr. Deutsch. Mal. Ges., 1913, p. 34),
made this species the type of a new genus, O.rynaia.

NODULARIA INGALLSIANA (Lea).

Shell elongated, inflated, scarcely subsolid, inequilateral, in-
flated: beaks full and high; anterior end rounded; base nearly
straight in front, full behind the middle, slopingly truncate
behind the swelling to the posterior point, which is situated
above the median line; posterior ridge near the dorsal line,
angled above, straight ; surface with delicate, irregular growth
lines ; epidermis dull, silky, olive with lighter bands, with faint

1000 NODULARIA

indications of rays; teeth very greatly compressed; muscle

scars shallow; nacre bluish, brilliant and iridescent behind.
Length 40, height 21, diam. 16 mm.
Cochin-China; Siam; Cambodia.

Unio ingallsianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 282, pl.
xxiv, fig. 41; Obs., V, 1852, p. 38, pl. xxiv, fig. 41—REEVE,
Conch. Icon., XVI, 1865, pl. xxv1, fig. 126.

Margaron (Unio) ingallsianus Lea, Syn., 1852, p. 36; 1870,
p-. 58.

Nodularia ingallsiana SIMPSON, Syn., 1900, p. 816. .

Oxynaia ingallsiana Haas, Con. Cab., Unio, 1910, pl. xvt, figs.
3-4-

This differs from NV’. pazii in the following slight characters:
It is not so wedge-shaped when viewed from above; it is fuller
at the basal inflation; it is more nearly equilateral and the nacre
is more brilliant. I have seen only the type, which is smaller

‘than N. pazii, while I have before me several specimens of the
latter. It is quite probable that a sufficient amount of material
would show that these two absolutely blend together.

Group of Nodularia trompi.

Shell small, subtrapezoidal, wider behind, slightly inflated,
with a rounded posterior ridge; beaks full, sculpture not
seen; surface covered with very fine, nodulous, somewhat zig-
zag corrugations, with upcurved posterior ridges on the pos-
terior slope; epidermis reddish-brown or black; hinge-teeth
compressed; pseudocardinals vertically striate.

NopuLARIA TROMPI (Drouet and Chaper).

Shell small, subrhomboid, narrower in front, convex, scarce-
ly subsolid, inequilateral ; beaks apparently moderately full and
not high; anterior end rounded, angled above; base nearly
straight, inflated near the posterior end; dorsum slightly curv-
ed; dorsal slope obliquely truncate; posterior ridge rounded,
ending in a rounded point near the base of the shell; surface
covered with fine, subnodulous sculpture, which is sometimes
connected and zigzagged; dorsal slope sculptured with fine,

NODULARIA f IOOI

radial wrinkles; epidermis reddish-brown becoming burnt-
blackish on the border; pseudocardinals compressed, two in
each valve; laterals delicate, curved; muscle scars shallow ;
nacre rich blue, iridescent behind.
Length 29, height 14.5, diam. 9.5 mm.
Borneo.
Unio trompi Drourr and Cuarrr, Mem. Soc. Zool. Fr., V,
1892, p. 153, pl. v1, figs. 8-Io.
Nodularia trompi Stmpson, Syn., 1900, p. 816.
Elongaria trompi Haas, Con. Cab., Unio, 1910, pl. xvi, fig. 6.
Remarkable for the peculiar subnodulous and granulated
sculpture, which, on the anterior end, becomes somewhat con-
nected and zigzagged, and for the intense burnt-brown and
blackish epidermis. ‘The nacre in the specimens before me is
very rich sky blue, and iridescent behind.

Group of Nedularia olivaria.

Shell thin, inflated, blue-green or olive-green, smooth, shin-
ing, with two or more faint ridges on the posterior slope ; beaks
and disk almost or quite destitute of sculpture; teeth greatly
compressed, lamellar.

NODULARIA OLIVARIA (Lea).

Shell very thin, subinflated, irregularly long elliptical, in-
equilateral; beaks moderately full and high, apparently with-
out sculpture, or with only faint indications of it; anterior end
rounded ; base lightly curved, full behind the middle, obliquely
subtruncated behind; posterior ridge showing indications of
being double, the region in front of it very full, the ridge end-
ing in a blunt point on or above the median line; surface ap-
parently smooth but having very fine growth lines and often
faint, microscopic, radial sculpture; epidermis delicate bluish-
green, often with a milky tint, darker on the dorsal slope
where there are faint rays; teeth compressed, elevated into
sharp lamellz ; beak cavities rather deep; nacre bluish with a
decided milky tint.

Length 40, height 22, diam. 15 mm.

India.

1002 NODULARIA

Umo olivarins Loa, Tr. Am? Phil SocehV> 1830 pce. op
xvI, fig. 38; Obs., I, 1834, p. 118, pl. xvi, fig. 38—HANLEy,
Biv. Shells, 1843, p. 195, pl. xx, fig. 32—CuHeENu, II.
Conch:, 1858, pl? viii; figs: ia aie, rb. — Koster Comen:
Cab. Unio, 1861, p. 244, pl. Lxxx, fig. 2.— Sowerby,
Conch. Icon., XVI, 1866, pl. xXxxvi, fig. 195.—HANLEy and
THEOBALD, Conch. Ind., 1876, p. 5, pl. x, fig. I.

Margarita (Unio) olivarius Lea, Syn., 1836, p. 26; 1838, p.
20;

Margaron (Unio) olivarius LEA, Syn., 1852, p. 30; 1870, p. 47.

Nodularia olivaria SIMPSON, Syn., 1900, p. 817.

Unio pumilio Kuster, Conch. Cab. Unio, 1862, p. 268, pl. xc,
fin,

A very delicate species remarkable for its faint, radial sculp-
ture and milky tint within and without.

NopuLARIA THEOBALDI Preston.

“Shell ovately rectangular, very slightly curved, gaping
anteriorly, moderately solid, concentrically striate, covered with
a dark, olivaceous periostracum; umbones small, not prom-
inent; dorsal margin somewhat arched; ventral margin slight-
ly excavated in the median region, otherwise straight ; anterior
side slightly produced and somewhat sharply rounded; pos-
terior side very obtusely rostrate, steeply sloping above, then
sharply rounded and again sloping inwards below. Cardinal
teeth in right valve roughly triangular, jagged, somewhat in-
wardly projecting, fitting between two teeth in the left valve,
which are roughened and of which the anterior is rather broad
and massive; lateral teeth in both valves elongate and nearly
straight ; anterior scars somewhat deeply excavated, especially
above ; posterior scars ovate, lightly impressed ; interior of shell
nacreous, shading from pale flesh-color to bluish, iridescent,
especially towards the posterior margin.

Long. 34, lat. 60, diam. go mm.”’ (Preston).

Type locality, Manipur, Assam.

Nodularia (Nodularia) theobaldi (Nevill, MS.), Preston,

Rec. Ind. Mus., VII, 1912, p. 202. j

NODUL ARIA 1003.

NODULARIA PECTEN Preston.

“Shell elongately ovate, rather thin, covered with a finely
laminiferous periostracum of a pale bluish-green color shad-
ing to yellowish-green towards the margins, finely concentrical-
ly striate and posteriorly ribbed, especially on the left valve;
umbones rather smal!, moderately prominent; dorsal margin
very slightly arched; ventral margin gently curved; anterior
side rounded; posterior side obtusely rostrate below, sloping”
above; hinge-teeth in both valves weak, anteriorly erect in
the right valve, sinuous and almost twisted in the left; poste-
rior teeth nearly straight, moderately elongate ; adductor scars
scarcely perceptible ; interior of shell pearly.

Long. 10, lat. 33.5, diam. 12 mm.” (Preston).

Type locality, Pitsanuloke, N. Siam. .

Nodularia (Nodularia) pecten Preston, Rec. Ind. Mus., VII,

1912, p. 292, pl. vitl, figs. 3, 4.

“The author follows Simpson in placing this and the next
two species (nuttalliana and involuta) in the Section Nodularia,
theugh, owing to the very different texture of the shells, it
is somewhat difficult to understand his reasons for so placing
them.”

NODULARIA NUTTALLILIANA (Lea}.

Shell irregularly elliptical, scarcely subsolid, subinflated, in-
equilateral; beaks high and rather full; anterior end rounded:
base lightly curved, full behind the middle, then obliquely sub-
truncated; dorsal slope obliquely subtruncate; posterior ridge
high, subangular, ending on the median line in a point; epi-
dermis yellowish-green with paler bands and faint rays on the
dorsal slope, nearly smooth, shining, feebly rayed; pseudo-
cardinals compressed, elevated; laterals curved, high; muscle
scars well marked; beak cavities impressed; nacre whitish or
yellowish, with a dark, bluish blotch in the beak cavities.

Length 25, height 20, diam. 13.5 mm.
India.

1004 NODULARIA

Unio nuttallianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p.
103 ; Obs., V5 1857,"ps 30; pl. xxx hee 25): [lave Nien:
Phila., III, 1858, p. 310, pl. xxx, fig. 25—Hantey and
THEOBALD, Conch. Ind., 1876, p. 19, pl. x1, figs. 5, 6.

Margaron (Unio) nuttallianus Lea, Syn., 1870, p. 74.

Nodularia nuttalliana SiMPSON, Syn., 1900, p. 817.

More solid and rather shorter than N. olivaria, to which it
is apparently closely allied. The epidermis is yellowish-green
with light bands and is not milky, the nacre is differently col-
ored and in the specimens examined has a dark, bluish blotch
in the cavities of the beaks. All the specimens I have seen
have the beaks slightly eroded, but they exhibit no traces of
sculpture.

NODULARIA INVOLUTA (Benson).

Shell irregularly ovate, slightly inequilateral, compressed
behind, swollen below the umbonal region, thin, polished ; pale
green obscurely radiate with yellowish, bluish above, polished,
with two or three dark rays on the dorsal slope; beaks very.
high and full, with a few light corrugations; anterior end
narrowly rounded above, cut away below; base rounded and
full about the middle, slopingly cut away behind to a point on
the median line; posterior ridge low; pseudocardinals elevated ;
laterals large, lamellar; nacre silvery.

Length 44, height 30 mm.

Assam.

Unio mvolutus Benson, Hanley Biv. Shells, 1856, p. 385, pl.
Xx, fig. 19.—Hanriry and THrosparp, Conch. Ind., 1876,
ps ro, pli xuiyshes 2:

Margaron (Unio) involutus Lea, Syn., 1870, p. 37.

Unio involuta SowERsBy, Conch. Icon., XVI, 1866, pl. xxxIv,
Ag: 177;

Nodularia involuta Stwpson, Syn., 1900, p. 817.

Differs from N. olivaria in being more ovate, in having much
higher beaks, which, according to Hanley, have some sculpture,
in being cut away at the anterior base, and having rays. A

NODULARIA 1005

striking form with an outline something like that of Plagiola
elegans, though not quite so much cut away on the dorsal
slope.

Group of Nodularia contradens.

Shell inflated, obovate, rhomboid. with a slight swelling at
the post-base, and a well-developed posterior ridge; beaks
full and high, the sculpture consisting of wavy, zigzag ridges,
which often extend over the shell as somewhat nodulous cor-
rugations ; pseudocardinals obliquely or vertically striate; lat-
erals curved; cavity of the beaks rather shallow.

NODULARIA CONTRADENS (Lea).

Shell scarcely subsolid, subrhomboid or obovate, convex to
subinflated, inequilateral; beaks but little elevated; posterior
ridge inclined to be double, ending in a feeble biangulation
at or below the median line; anterior end rounded, somewhat
narrowed; base line curved, full behind the middle; dorsal
slope obliquely truncate; surface with fine growth lines and
indications of nodulous sculpture, the dorsal slope with faint,
fine plications; epidermis dirty yellowish-green, darker and
somewhat rayed behind the posterior ridge, subshining ; teeth
much compressed ; laterals curved ; muscle scars shallow ; nacre
bluish.

Length 58, height 34, diam. 21 mm.

Length 55, height 32, diam. 18 mm.

Java.

Unio contradens Lea, Tr. Am. Phil. Soc., VI, 1838, p. 75, pl.
xvul, fig. 58; Obs., II, 1838, p. 75, pl. xvirt, fig. 58— Han-
LEY, Biv. Shells, 1843, p. 200, pl. xx, fig. 8—CueENu, IIl.
Conch., 1858, pl. xx1x, figs. 4, 4a, 4b—Rerve, Conch. Icon.,
XVI, 1865, pl. xxx, fig. 149.

Margarita (Unio) contradens Lra, Syn., 1838, p. 25.

Margaron (Unio) contradens Lea, Syn., 1852, p. 39; 1870,
p. 46. |

Nodularia contradens Simpson, Syn., 1900, p. 817.

Contradens contradens Haas, Conch. Cab., Unio, 1912, pl.
18, figs. 2-5.

1006 NODULARIA

Unio javanus Lea, Pr. Am. Phil: Soc, 1, 1840, p. 285; Pr.
Am: Phils Soe; “VII 18429 p220) pleexvinn, somes ze Obs:
III, 1842, p. 58, pl. xvi, fig. 37—CuHENU, Ill. Conch., 1858,
pl. xxvut, figs. 4, 4a, 4b.—Kuster, Conch. Cab. Unio, 1856,
ps .138;). pl. IA, fisting 1861" p.-236; .plsiaecix ties ao —
Sowerby, Conch. Icon., XVI, 1868, pl. xc, fig. 480.

Margaron (Unio) javanus La, Syn., 1852, p. 30.

Unio exilis DuNKER, Zeits. fur Mal., II, 1846, p. 109.—Mous-
son, I,. and S$. W. Moll. Java, 1849, p. 92, pl. xv1, fig. 3.

Margaron (Umo) exilis LEA, Syn., 1852, p. 20.

Unio mutatus Mousson, L. and S$. W. Moll. Java, 1849, p. 92,
pls evie fies. 12:

Margaron (Unio) mutatus LEA, Syn., 1852, p. 20.

Unio mederianus Kuster, Conch. Cab. Unio, 1861, p. 242, pl.
Ty SNORE
The type does not seem to be in the Lea collection, but it

contains a typical example of larger dimensions, the measure-

ments of which | have given.
Haas has recently, (Nachr. Deutsch. Mal. Ges., 1913, p. 35),.
made this species the type of a new genus, Contradens.

NoOpDULARIA SEMMELINKt (von Martens).

“Shell transversely elliptical, solid, concentrically and rather
coarsely striate, yvellowish-brown, blackish posteriorly ; anterior
end short, rounded; posterior end elongate, subrostrate, with
three angular lines radiating from the beaks, the lowest very
obtuse, raised, then obtusely biangulated; ventral margin
slightly arcuate, distinctly ascending anteriorly; beaks situated
at 2/7 of the length; umbones quite inflated, eroded, sculptured
in front and behind with elevated, granulated lines, concen-
tric in front and radial behind. Areola distinct, narrowly
lanceolate, horizontal, smooth; area prominent, convex. Nacre
pale yellowish-flesh-color, with a deeper colored submarginal
band. Cardinal teeth compressed, lamellar, obliquely rugose,
subcrenulate, two in the right valve, inequal, one in the left
valve with an accessory obtuse, subvertical tubercle. Poste-
rior teeth lamellar, not very heavy, quite arcuate, obliquely ru-

NODULARIA 1007

gose, subcrenulate, one in the right valve, two in the left,
of equal length, the superior much lower. Accessory anterior
muscular impression small, subcircular, close to the adductor.

Length 71, height 40, diam. 29.5, length of ligament 20
mm.” (von Martens).

Type locality, Tana-laut, Borneo.

Unio semmelinki von Martens, Sitzber. Ges. Nat. Fr. Ber.,

1891, p. I111.—SrMPpson, Syn., 1900, p. 834.

Contradens semmelinkt Haas, Conch. Cab. Unio, 1912, pl. 20,

figs: 6.7.

“Related to LU’. javanicus (mutatus Mouss), from Java, but
larger, proportionately thicker, more inflated, with stronger
striz, more obtuse behind, the beak sculpture extends less
widely downward behind and lacks the sharply angled lines
that in the example of U. mutatus in the Dunker Collection
from v. d. Busch (with a proportionately equal erosion of
the beaks) are clearly present, though entirely lacking both
in the description and the figure of Mousson. The color,
both externally and internally, is also different. On the other
hand, the hinge is very much the same.

As I have seen only a single specimen from either Borneo
or Java, it is impossible to say whether these differences are
constant or not.”

NoDULARIA LATICEPS (von Martens).

“Shell elliptical, inflated, solid, concentrically striate; epi-
dermis brown, opaque; anterior end rounded; posterior elon-
gated. subrostrate; an obtusely angulated line extends back-
wards and downwards from the beaks, becoming obsolete
posteriorly ; umbones wide, beaks moderately prominent, at
about 1/3 of the length; anterior and posterior dorsal margin
subhorizontal; posterior sloping obliquely; ventral slightly
curved; cardinal teeth compressed, subelongate, parallel with
the dorsal margin, slightly crenulate; interior bluish-white,
pale yellowish towards the umbones.

a. Length 80, height 41, diam. 34 mm.

b. Length 66, height 38, diam. 33 mm.” (von Martens).

Type locality, Lake Danau Baru, Indragiri, Sumatra.

1008 NODULARIA

Unio laticeps von Martens, Nachr. Deutsch. Mal. Ges., 1900
prors

Contradens semmelinki laticeps HAas, Conch. Cab., Unio, 1912,
pl..20; figs Sy:pl, arses 7,

7;

“Greatest diameter in ‘a’ decidedly, in ‘b’ only slightly behind
the beaks.”

NODULARIA HAGENI (Strubell).

“Shell scarcely moderate, elongate-ovate, not at all ventri-
cose, rather thin but quite solid, rudely costulate-striate, some-
what shining, blackish-brown. Anterior end much attenuated,
compressed ; posterior end elongate, the greatest height being
at the junction of the dorsal and posterior margins. Dorsal.
margin ascending, scarcely curved, meeting the posterior mar-
gin at a distinct angle, passing in to the depressed anterior
margin in a scarcely angulated curve; ventral margin sub-
horizontal, forming with the obliquely descending, sub-bian-
gulated posterior margin a straight, obliquely rounded-truncate
rostrum. Umbones anterior, depressed, much eroded; areola
almost obsolete; area elongate, compressed, indistinctly becar-
inate; ligament thin, quite long. Hinge very weak; tooth of
the right valve almost obsolete ; lateral elongate, narrow. Mus-
cular and pallial impressions superficial; nacre bluish, livid-
brown towards the umbones.

Length 55, height 30, diam. 17 mm.” (Strubell).

Type locality, South Sumatra.

Microcondylea hageni STRUBELL, Nachr. D. Mal. Ges. 1897,

p. 8.

Contradens hagenit Haas, Conch. Cab., Unio, 1912, pl. 18, figs.

Gi 7:

NoDULARIA DIMOTA (Lea).

Shell irregularly rhombeid, inflated, subsolid, inequilateral,
narrowed and rounded in front; beaks full and considerably
elevated ; posterior ridge double, ending in a biangulation near
the base line; base line curved, fuller behind the middle; dor-
sal slope obliquely truncate; surface usually more or less cov-
ered with fine, subconcentric, slightly zigzagged sculpture, with

NODULARIA 1009

radial plications on the dorsal slope; epidermis dark tawny-

greenish or brownish with a smoky tint, with one or two pos-

terior rays, somewhat shining; teeth compressed, the laterals
curved; muscle scars not deep; nacre bluish-white.

Length 58, height 33, diam. 24 mm.

Sumatra.

Unio sumatrensis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p.
los. hence Nel ehia.. LV, TO00, p. 230, pl xxxiv, fig.
118; Obs., VII, 1860, p. 57 pl. xxxiv, fig. 118.

Margaron (Unio) dimotus LEA, Syn., 1870, p. 30.

Nodularia dimota SIMPSON, Syn., 1900, p. 818.

Contradens dimotus Haas, Conch. Cab., Unio, 1912, pl. 19,
figs. I-5.

Unio hageni StRuBELL, Nachr. Deutsch. Mal. Ges. 1897, p. 10.

Unio hagnei Simpson, Syn., 1900, p. 862.

Rather solider, more inflated and darker colored than N. con-
tradens. ‘The sculpture is peculiar, and generally more pro-
nounced than in contradens.

Changed to dimotus by Lea because sumatrensis was pre-
occupied for a Unio by Dunker.

NODULARIA FISCHERIANIA (Morlet).

Shell subrhomboid, inflated, rather solid, inequilateral ;
beaks moderately full and high; posterior ridge well develop-
ed, subangular above, double below, ending in a biangulation
at and below the median line; anterior end a little narrowed,
rounded, somewhat angulate above; base line lightly curved,
full behind the middle; dorsal line curved; dorsal slope
obliquely and decidedly truncated; surface nearly smooth;
olive-green with lighter bands; teeth much compressed, lam-
ellar; muscle scars well marked; nacre bluish-white, yellowish
in the cavities.

Length 58, height 33, diam. 27 mm.

Cambodia.

Unio fischerianus Morir, Jl. de Conch., XX XI, 1883, p. 109,

pl. tv, fig. 6.

Nodularia fischeriana Simpson, Syn., 1900, p. 818.

IOIO NODULARIA

Contradens dimotus fischerianus Haas, Conch. Cab., Unio,
1912, pl. 19, fig. 8.
Morlet states that the pseudocardinals are but slightly in-
dicated. ‘The shell appears to be nearly smooth and devoid of
folds or nodules.

NopULARIA ANODONTAFORMIS (‘lapperone-Canefri).

Shell large, subrhomboid, subsolid, inequilateral, somewhat
inflated ; beaks high and full; anterior end subangulate above,
rounded below ; base lightly curved, full a little behind the mid-
dle; from the inflation to the hinder point the outline is
straight ; posterior ridge well developed, rounded, ending near
the base of the shell in a blunt point or feeble biangulation ;
dorsal slope strongly and obliquely truncate; surface with ir-
regular, concentric sculpture and faint indications of nodulous
or zigzag sculpture; epidermis reddish-brown, olive-tinted on
the umbonal region, sometimes with a very wide, nearly black
posterior ray, shining; left valve with a compressed, ragged
pseudocardinal and two remote, delicate laterals; right valve
with two pseudocardinals and one lateral; dorsal scars large
and conspicuous ; anterior scars irregular; posterior scars shal-
low; pallial line sometimes having indications of a posterior
sinus ; nacre whitish, brownish, iridescent behind.

Length 121, height 64, diam. 43 mm.

New Guinea.

Unio (Microdontia) anodonteformis ‘TAPPERONE-CANEFRI,

Ann. Mus. Genoy., XIX, 1883, p. 295, pl. x1, figs. 3-5.
Nodularia anodontefornus Simpson, Syn., 1900, p. 818.
Microdontia anodonteformis Haas, Con. Cab., Unio, 1910, pl.

TO) 112210,

A fine, large species, of which four matched valves are be-
fore me. ‘The beaks of all these are somewhat eroded, but
it is probable that they have but slight sculpture. The nacre
is slightly thickened in front.

NopULARIA OVA'A (Haas).

“Shell almost equilateral, high, solid. Outline elliptical,
showing only at the hinder end a blunt angle. Beaks almost
central, situated at 41/too of the length, rather prominent and

NODULARIA IOII

inflated. Beak sculpture unknown on account of the great
erosion. Area low. Hinge weak; two small, lamelliform
cardinal teeth in the right valve, the lower stronger than the
upper; one rather strong cardinal tooth in the left valve.
Angle of the cardinal teeth 35°, of the lateral teeth 20°. Mus-
cular impressions, anterior large, ear-shaped, not deep, poste-
rior large, somewhat more shallow; dorsal impressions deep.
Nacre porcellaneous, bluish-white. Epidermis chestnut-brown,
strongly, but irregularly, furrowed.

Length 81, height 56, diam. 37 mm.”’ (Haas).

Type locality, New Guinea, (Fly River?).
Microdontia ovata Haas, Nachr. Deutsch. Mal. Ges., 1910, p.

100; Con. Cab. Unio, 191!0, pl. 16, fig. 5.

NopULARIA SACELLUS (Drouet and Chaper).

Shell irregularly rhomboid, thin, narrowed in front, inequi-
lateral, convex; beaks only moderately full and high; dorsal
line nearly straight; anterior end rounded; base curved and
full behind the middle; dorsal slope almost squarely truncated ;
posterior ridge well developed, somewhat double, ending in
a feeble biangulation near the base of the shell; epidermis
dirty brownish-green, sometimes banded; surface almost
smooth, with a few faint plications on the dorsal slope; teeth
very delicate, much compressed ; in each valve almost under the
beaks there is a rounded tubercle; muscle scars shallow; nacre
bluish, salmon in the cavities, iridescent behind.

Length 55, height 35, diam. 18 mm.

Borneo.

Unio sacellus Drover and CuHaprrrR, Mem. Soc. Zool. Fr., V,

1892, p. 148, pl. v, figs. 4-6.

Nodularia sacellus Stmpson, Syn., 1900, p. 818.
Contradens dimotus sacellus Haas, Conch. Cab., Unio, 1912,

pl. 109, fig. 6.

I was at first inclined to believe that this and the next spe-
cies were merely varieties of the same thing, but close examina-
tion reveals several minor differences. This species is a
little higher in proportion to length, is more squarely truncate

IOI2 NODULARIA

behind, is lighter colored; it has the peculiar tubercles on the
hinge, which seem to be lacking in Jugens, and the nacre is a
little different.

NODULARIA LUGENS (Drouet and Chaper).

Shell irregularly rhomboid, narrowed in front, thin, convex,
inequilateral; beaks moderately full and high; anterior end
rounded, angled above; base line curved, full behind the mid-
dle; dorsal line lightly curved; dorsal slope strongly, obliquely
truncated, posterior ridge well developed, ending in a point
near the base; surface nearly smooth, with some faint plica-
tions on the dorsal slope; epidermis rich reddish-brown, sub-
shining; teeth delicate, compressed; muscle scars shallow;
nacre blue, iridescent behind.

Length 54, height 32, diam. 18 mm.

Borneo.

Unio lugens Drourr and CHaper, Mem. Soc. Zool., Fr., V

1892, p. 147, pl. v, figs. 1-3.

Nodularia lugens Stmpson, Syn., 1900, p. 818.
Contradens dimotus lugens Haas, Conch. Cab., Unio, 1912, pl.

LO MLS ze

The posterior ridge of the specimens I have seen is single,
while in sacellus it is somewhat double; the nacre is deep blue
with only a faint hint at yellowish in the beak cavities, while
in sacellus it is lighter colored and decidedly flamed with sal-
mon in the beak cavities.

7

NopuLARIA INA&OUALIS (Rochebrune).

Shell subrhomboid, inflated, thin, inequilateral; beaks full
and high, ornamented with granulous, angular wrinkles ; pos-
terior ridge full, somewhat double below, ending at and below
the median line in a faint biangulation; anterior end a very
little narrowed, rounded: base line almost evenly curved,
slightly fuller behind the middle: dorsal line curved; dorsal
slope obliquely truncate; epidermis brown or green-brown;
teeth compressed; muscle scars shallow; nacre bluish-white.

Length 47, height 29, diam. 21 mm.

River Srakeo, Siam.

NODULARIA 1013

Unio mequalis ROCHEBRUNE, Bull. Soc. Phila., 1882, p. 44.—

Simpson, Syn., 1900, p. 862.

Oxynaia inequalis Haas, Con. Cab., Unio, 1910, pl. xtra, fig.

Re; pla XV; fie. 7.

Unio semidecoratus Moret, J!. de Conch., XXXVII, 1880,

p. 192, pl. virt. fig. 4.

Nodularia semidecorata SIMPSON, Syn., 1900, p. 810.

The figure of this species given by Morlet is rather inferior.
The umbonal region seems to be decidedly sculptured; the
beaks are higher, and the shell is thinner than is the case with
N. fischeriana.

NopULARIA RUSTICA (J,ea).

Shell subsolid, irregularly ovate, inflated, inequilateral ;
beaks very full and high, their sculpture coarse, zigzag corru-
gations, which extend out on to the disk and gradually change
to subnodulous sulcations; lunule well marked; anterior end
narrow ; base line almost evenly curved, but slightly produced
behind the middle; hinge line with the compressed teeth
curved; posterior ridge angled above; narrowly rounded be-
low and ending in a blunt point near the median line; epider-
mis dirty yellowish-green, darker behind; beak cavities rather
deep; muscle scars impressed ; nacre whitish or bluish-white.

Length 50, height 36, diam. 25 mm.

Siam ; Cambodia.

Umio rusticus Lea, Pr. Ac. N. Sci. Phila:, VIII, 1856, p. 93;
Ohana tee pb pl xxv, ews: Jl Ac. »N. Sci. Phila.,
III, 1858, p. 204, pl. xxv, fig. 7—Morexer, Ser. Conch., IV,
T9755p: 353, pl: Xv, fig: 7.

Margaron (Unio) rusticus Lea, Syn., 1870, p. 31.

Nodularia rustica Stwpson, Syn., 1900, p. 819.

Contradens rusticus Haas, Conch. Cab., Unio, 1912, pl. 21,
figs. 2-4.

Unio paivanus Morier, Jl. de Conch., XIII, 1865, p. 227.

Unio cambojensis SowrRny, Conch. Icon., XVI, 1866, pl. xLu,
fig. 231.

IO14 NODULARIA

The beaks are fuller and higher than those of U. dautzen-
bergi; the dorsal slope is not truncated; the sculpture on the
disk is not so rude or nodulous.

NopDULARIA TUMIDULA (Lea).

Shell long ovate, subinflated, subsolid, inequilateral; beaks
high and full, with a large lunule in front of them; posterior
ridge low, angular above, somewhat double below, ending in a
faint biangulation below the median line; anterior end round;
base line almost evenly curved, but slightly produced behind
the middle; surface almost smooth, with some feeble corruga-
tions and wrinkles on the dorsal slope; epidermis dirty yellow-
ish-green, with two or three faint, dark rays on the dorsal
slope; hinge line almost evenly curved; teeth delicate ; pseudo-
cardinals compressed; laterals wavy; muscle scars well mark-
ed: beak cavities impressed; nacre bluish-white, inclining to
iridescent.

Length 49, height 27, diam. 18 mm.

Siam ; Cambodia.

Unio tumidulus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 93;
Obs., VI, 1857, ps 15. pl. Xv, tis, 9 = | Ac NE Sere eines
IIT, 1858, p. 295, pl. xxv, fig. 9.—Sowrrpy, Conch. Icon.,
XV 1) 1868, plouxaca x, fies G2"

Margaron (Unio) tumidulus Lea, Syn., 1870, p. 39.

Nodularia tumidula Stmpson, Syn., 1900, p. 814.

Oxynaia tumidula Haas, Con. Cab., Unio, 1910, pl. 14, fig. 4.
I have only seen the type, a dead shell, and not in excellent

condition. ‘his species does not seem to be very closely re-

lated to any other, but after giving it careful study I am in-
clined to place it in the contradens group.

NGpULARIA DAUTZENBERGI (Morlet).

Shell irregularly subelliptical or subrhomboid, rather solid,
inflated; beaks full and high, sculptured with strong, zigzag
sculpture, which extends well over the umbonal region, grad-
ually changing to irregular folds and nodules on the disk ; pos-
terior ridge strong, angled, sometimes faintly double, ending

NODULARIA IOI5

in a blunt point below the median line; hinge line strongly
curved; anterior end rounded, subangulate above; base line
curved, quite full just behind the middle; dorsal slope ob-
liquely truncated and having wrinkled, subradial ridges; epi-
dermis yellowish-green, darker behind ; teeth lamellar ; pseudo-
cardinals and laterals curved; muscle scars impressed; nacre
bluish-white.

Length 50, height 31, diam. 24 mm.

River Srakeo, Siam.
Unio dautzenbergi Morier, Jl. de Conch., XX XVII, 1880, p.

190, pl. vit, fig. 5.
Nodularia dautgenbergi SIMPSON, Syn., 1900, p. 819.
Contradens dautzenbergi Haas, Conch. Cab., Unio, 1912, pl.

21, figs. 6-7.

A rather solid species distinguished by its coarse, irregular
sculpture. The hinge line is quite strongly curved; the nacre
is rather dull.

NODULARIA SOBOLES (Fischer).

Shell irregularly rhomboid, inflated in front, wedge-shaped
behind, solid; beaks rather full and high; anterior end some-
what truncated; base line curved, full about the middle, in-
curved between this and the posterior end; hinge line curved
throughaut; dorsal slope scarcely truncate; posterior ridge
inclined to be double, ending in a blunt, rounded point or faint
biangulation at the base of the shell: surface corrugated, the
ridges often interrupted; epidermis brownish-green; pseudo-
cardinals not strong ; laterals curved; nacre whitish.

Length 68, height 39, diam. 32 mm.

Siam.

Unio siamensis Moruet, Jl. de Conch., XX XVII, 1889, p. 194,

plevil, fie. 2:

Unio soboles Fiscuer, Bull. Soc. d’Aut., 1891, p. 227.
Nodularia sobolus Stspson, Syn., 1900, p. 819.
Contradens sobolus Haas, Conch. Cab., Unio, 1912, pl. 21,

fig. 5.

First called Unio siamensis by Morlet, but as that name had
been used by Lea, Fischer changed it to Unio soboles. Closely

IO16 NODULARIA

related to N. dautsenbergi and possibly only an old state ot
that species. The posterior end is somewhat drawn out and
curved downward and the shel! is said to be wedge-shaped
viewed from above. It is rather more elongated than the
single specimen of dautzenbergi, which belongs in the National
Museum. By a typographical error this name was spelled
sobolus in the Synopsis.

NCDULARIA VERBECKI ( Bottger).

Shell subrhomboid, somewhat inflated, inequilateral, sub-
solid; beaks only moderately full and high; anterior end nar-
rowly rounded; base line curved; dorsal line curved ; posterior
ridge full, double, ending at and below the median line in a
biangulation; dorsal slope obliquely truncated; surface sculp-
tured with coarse, irregular folds or undulations; the teeth
compressed, curved.

Length 47, height 26, diam. 18 mm.

Length 41, height 25, diam. 15.5 mm.

Singkarah Lake, Sumatra.

Unio verbecki Bortcrr, Zool. Erg. Nied. Ost. Ind., IV, 1897,

p. 80, pl. v, figs. 1, 2, 4, 5.
Nodularia verbecki SIMPSON, Syn., 1900, p. 810.

Contradens verbecki Haas, Conch. Cab., Unio, 1912, pl. 22,

figs. 1-4.

Von Martens credits this to Bottger manuscript. He does
not give the color of the epidermis or nacre in his description.
The species is close to N. dautzenbergi but is less inflated and
does not have so strong a posterior ridge. It seems to be a
little longer in proportion to its height.

Section Rapratura Simpson.

Radiatula Simpson, Syn., 1900, p. 820.

Shell rather solid, triangular oval, with high beaks, which
are but little inflated, not very full at post-base, and bluntly
pointed behind, the beaks and entire surface covered with radi-
ating, occasionally slightly zigzag or divaricate ridges, which
are cut more or less into nodules or cancellations by concen-

NODUT,ARIA IOI7

tric sulcations, the sculpture of the posterior slope stronger,

and curving upward; pseudocardinals of the left valve 2 to 3,

ragged, the anterior larger, two in the right valve, with a par-

allel sided socket, the larger teeth compressed but rather solid.
Type, Unio crispisulcatus Benson.

NODULARIA CRISPISULCATA (Benson).

Shell somewhat subtriangulate, slightly inequilateral, con-
vex to subinflated, subsolid; umbonal region high; beaks ele-
vated but rather compressed, pointed, sculptured with numer-
ous, distinct, radial-zigzag ridges, these ridges extending all
over the shell and on the later growth are crossed by fine, de-
cided, concentric sculpture causing the surface to be reticulated
in a marked degree; along the full, rounded posterior ridge the
sculpture is divaricate; anterior end narrowed and rounded;
base line lightly curved, usually a little fuller behind the mid-
dle; outline of dorsal slope curved down to the rounded or
sometimes biangulate point; epidermis yellowish-green to
brownish, often with lighter and darker bands, dull; hinge line
strongly arched; pseudocardinals subcompressed, ragged ; lat-
erals remote, rather short; muscle scars well marked; nacre
whitish, often yellowish in the cavities.

Length 52, height 33, diam. 21 mm.

Length 4o, height 29, diam. 16 mm.

Burma.

Unio crispisulcatus BENsonN, Ann. and Mag., X, 1862, p. 193.
—Sowersy, Conch. Icon., XVI, 1866, pl. xuix, fig. 262.—
HANLEY and TueropaLp, Conch. Ind., 1876, p. 6, pl. x1
fig. 5:

Margaron (Unio) crispisulcatus Lea, Syn., 1870, p. 31.

Nodularia crispisulcata StMPSON, Syn., 1900, p. 820.

A large series of this form is before me. It is one of the
few distinctly cancellated Uniones. Notwithstanding its sub-
triangular form, it shows relationship to the other forms of
Nodularia, especially to such species as N. occata and N.
gratiosa.

1018 NODULARIA

NopuLARIA LIMA Simpson.

Shell subrhomboid, inequilateral, subsolid, subcompressed ;
beaks not greatly elevated; anterior end rounded; base line
lightly curved; dorsal line curved; outline of dorsal slope
obliquely subtruncated; posterior ridge full, rounded, ending
in a rounded point near the base; sculpture said to be some-
thing like that of U. scobina, but more linear and radial; epi-
dermis olivaceous; pseudocardinals strong, ragged; laterals
slightly curved; nacre bluish.

Length 30, height 20 mm.

Assam ; Cambodia.

Unio radula BeENson, in Hanley, Biv. Shells, Supp., 1856, p.
382.—Han_ey and THEOBALD, Conch. Ind., 1876, p. 5, pl. x,
fig. 3.

Dysnomia radula RocHEBRUNE, Bull. Soc. Phil., VI, 1882, p.
42. ae

Nodularia lima Stimpson, Syn., 1900, p. 820.

I know nothing of this species except from the figures and
brief description. It may belong in the group of Nodularia
cerulea, though the description in the Bivalve Shells would
seem to indicate that the sculpture was inclined to be radial.
The name radula was used by Say for a Unio in 1829, hence
T have changed the name of this to Jima.

Var. siliguriensis Preston.

“Shell inequilateral, ovate oblong, reddish-brown, sculptured
with concentric lines of growth and oblique, transverse wrink-
les, these latter being especially marked posteriorly ; anterior
side rounded; posterior side acuminately rounded; dorsal mar-
gin arched; ventral very slightly contracted in the middle;
umboes much eroded; interior of shell iridescent, pale bluish-
white.

Longe.21, lat.37:35 mm: (Preston):

Unio siliguriensis Preston, Rec. Ind. Mus., Calcutta, II, 1908,

Pp. 47.

Nodularia lima var. siliguriensis Preston, Rec. Ind. Mus., VI,

IOU2 pi 2on*

NODULARIA 1019

Section CaLarura Conrad, 1853.

Celatura Conran, Pr. Acad. Nat. Sci. Phila., 1853, p. 267.

Shell elliptical, pointed or rounded behind, usually slightly
produced at the post-base; beak sculpture consisting of zig-
zag ridges, which are generally quite pustulous, the sculpture
often extending on to the usually rayed disk ; teeth compressed ;
pseudocardinals lamellar.

Animal described under Nodularia.

Type, Unio egyptiacus Cailliaud.

Group of Nodularia egyptiaca.
Characters the same as of the section.

NoDULARIA AGYPTIACA (Cailliaud).

Shell irregularly elliptical, subinflated, usually rather thin,
subinequilateral ; beaks moderately high and full, their sculp-
ture consisting of subnodulous, zigzag ridges, sometimes of
sharp or elevated pustules; dorsal line curved; anterior end
narrowed and rounded; basal outline curved, fuller behind the
middle; dorsal slope obliquely truncated; posterior ridge
rounded, ending in a blunt point about on the median line;
surface with irregular growth lines; epidermis generally
smooth, with slight wrinkles on the dorsal slope, yellowish-
green, banded, with faint, green rays, usually ashy on the
umbonal region, somewhat shining; teeth lamellar; pseudo-
cardinals one in the left valve and two in the right ; laterals two
in the left valve and one in the right; muscle scars shallow ;
nacre bluish.

Length 42, height 29, diam. 19 mm.

Nile system; Upper Cazamance, West Africa (Vignon) ;
both sides of the equator in Central Africa (Dohrn).

Unie species nuovo, SAvicny, Icon. Moll., Egypt, 1813,’ pl.

vit, figs. 3-6.

Unio egyptiaca CAILLIAuD, Voy. a Méroé, II, 1826, pl. Lx1,

figs. 6, 7.

Margarita (Unio) egyptiacus Lea, Syn., 1838, p. 21.

1020 NODULARIA

Margaron (Unio) egyptiacus Lea, Syn., 1852, p. 32; 1870, p.
50.

Unio egyptiacus Hanury, Biv. Shells, 1843, p. 198, pl. xx,
fig. 56.—Kustrer, Conch. Cab., 1856, p. 157, pl. xLv, fig. 2.—
REEVE, Conch. Icon., XVI, 1865, pl. xxv1, fig. 132.—JICKELI,
(part), Fauri. Moll. N. O. Af., 1874, p. 271, pl. x, figs. 1-6, 8.
—Kone.t, Icon., new ed., 1886, p. 25, pl. xLiv, figs. 262-265.

Nodularia egyptiaca SIMPSON, Syn., 1900, p. 821.—PALLARY,
Mem. Inst. Egypt, VI, 1900, p. 78, fig. 8.

Unio eucyphus Bourcuicnat, Rev. et Mag., LX, 1857, p. 19,
pl. 11, figs. I1-3.—Kose.t, Icon., new ed., XVIII, 1912, p.
55, pl DVIL hg: 2672:

Unio bourguignati LANDRAN, Seance Soc. Sci. Nat. Seine,
1864, p. 5) pl. ties, -1-=

Pharaonia bourguignati RocuEBRUNE, Bull. Soc. Mal. Fr., II,
1886, p. 113.

Nodularia gaillardott “BourcuicNar’ PaLLary, Mem. Inst.
Egypt, VI, rgo9, p. 78, pl. v, figs. 7, 8.

Higher in proportion to length, thinner, more distinctly

rayed and having less solid teeth than N. nilotica, with which
~ it has been confounded. ‘The beak sculpture is sometimes al-
most wholly nodulous, at other times it consists of zigzag, sub-
nodulous ridges.

NopubaARtIA NILOTICA (Cailliaud).

Shell long elliptical or somewhat obovate, subinflated, sub-
solid, inequilateral ; beaks moderately raised, sculptured with
‘broken, subnodulous, zigzag ridges ; posterior ridge full, round-
ed, ending in a blunt point at or below the median line; hinge
line lightly curved; anterior end a little narrowed, rounded,
sometimes subangulate above; base line curved, fuller behind
the middle; dorsal slope obliquely truncate ; surface with irreg-
ular, subsulcate growth lines, often with slight, swbradial
ridges behind ; epidermis often wrinkled, greenish, often band-
ed and very faintly rayed, with a reddish tint on the umbonal
‘region, subshining; pseudocardinals subcompressed, ragged ;

NODULARIA 1021

laterals curved; anterior scars well marked; nacre bluish
whitish or reddish.

Length 55, height 32, diam. 1g mm.

Length 52, height 30, diam. 21 mm.

,

Nile system; Senegal and Upper Cazamance (Vignon).
Unio nilotica CaILLiAup, Voy a Méroé, II, 1826, pl. Lx1, figs.
8, 9.—Han.ey, Biv. Shells, 1843, p. 197, pl. xx1, fig. 39.
Margarita (Unio) niloticus Lia, Syn., 1836, p. 29; 1838, p. 21.
Margaron (Umo) niloticus Lea, Syn., 1852, p. 31; 1870, p. 50.
Nodularia niiotica StMpson, Syn., 1900, p. 821.—PALLARY,

Mem. Inst. Egypt, VI, 1909, p. 77, pl. 1v, figs. 1, 2.

Unio pumilus ZEIGLER, manuscript and of authors.
Unio parreysst Puriiprt, Conch., III, 1848, p. 81, pl. v, fig. 6.
Nodularia (Celatura) parreysst PatiAry, Mem. Inst. Egypt,

V1, 1909; p: 78, pl. v, fig:'6.

Umio rugifer Kuster, Conch. Cab. Unio, 1856, p. 157, pl. XLv,

figs. 3, 4.

Unio sennaariensis Kuster, Conch. Cab. Unio, 1862, p. 280,

pl. xciv, figs. 5, 6.

Unio eneus Jickri1, Faun. Moll. N. O. Af., 1874, p. 274, pl.

1%, fis. 2.

This seems to differ from N. egyptiaca with a fair degree
of constancy, in being solider, more elongated, more inequi-
lateral, and in having shorter, more solid, ragged pseudocardi-
nals. Many specimens entirely lack rays.

Var. prunert “Bourguignat” Pallary.

“Differs from the type (parreysst), by its smaller size, more
elongated, less elevated shape, !ess thickness, more angulated
posterior margin. In this species the anterior and posterior
margins are fan-shaped.” (Pallary).

Type locality, The Nile between the two cataracts.

Unio egypticus Jickett, Fauna N. Ost. Afrik. 1874, pl. x,

fie) 7.

Nedularia (Celatura) parreyssi var. prunert “BOURGUIGNAT”

PaiLtAry, Mem. Inst. Egypt, VI, 1909, p. 78.

N@2Z2 NODULARIA

NoODULARIA EURYSSELLINA (“‘Letourneux” Pallary).
y

“This form, which belongs to the group of niloticus, is an
unpublished species, which we found in the album of the
Naiades of the Bourguignat collection drawn by M. Locard,
The type came from the canal Mahmoudich in Lower Egypt.
Our specimens have thin valves, of a beautiful clear rose-color,
covered with a greenish epidermis.

Length 25, height 23, diam. 15 mm.” (Pallary).

Unio eurysellinus “LeTOURNEUX” PALLARY, Bull. Inst. Egypt,

Ti 2002; "p04; ple 11 hee at:

Nodularia (Celatura) eur'ssellina PAttARY, Mem. Inst. Egypt,

VI, 1900, p. 78.

NopvuLARIA Mystica (“Bourguignat” Pallary).

“We do not find any difference between the specimens from
the Upper Nile and those from a canal near Suez, named Unio
mysticus in the collection Bourguignat. ‘This species, like a
large number of the important series that Bourguignat pro-
posed to publish in an “Histoire Malacologique de l’Egypt,”
is yet unpublished. It is to the courtesy of M. Arnould Lo-
card that we owe our knowledge of this series, which we pro-
pose to publish in the near future.

Length 40, height 23, diam. 14.5 mm.” (Pallary).

Unio mysticus “BouRGUIGNAT”’ PALLARY, Bull. Inst. Egypt,

A , 1902; :p945 play fiss3:

Nodularia (Celatura) mystica PAtsAry, Mem. Inst. Egypt,

Vil, TOOOs ps 7S:

NODULARIA GERRARDI (von Martens).

Shell elliptical, inflated, subsolid, inequilateral; beaks full
and high, the umbonal region somewhat elongated, sculptured
with V-shaped ridges; hinge line curved; anterior end round-
ed, base lightly curved, a little fuller behind the middle; pos-
terior ridge widely rounded, ending in a blunt point about on
the median line; epidermis dark brown; pseudocardinals rath-
er small, compressed; laterals curved; nacre rose-colored or
bluish.

Length 51, height 30.5, diam. 26.5 mm.

Lake Tanganyika.

NODULARIA 1023

Unio gerrardi von Martens, Besch. Ost. Af., 1897, p. 223, pl.
VIt, fig. 5.
Nodularia nilotica var. gerrardi Simpson, Syn., 1900, p. 822.
Possibly distinct from N. nilotica. The beaks appear to be
fuller, higher and more elongated than those of nilotica, and
von Martens states that they have V-shaped sculpture instead
of scattered pustules, but there is much variation in this char-
acter even in different specimens of the same species in this
group. The shell is probably more inflated than that of N.
nilotica.

NODULARIA BAGDADENSIS (Bourguignat).

Shell somewhat elongated, irregularly elliptical, rather thin,
convex or but slightly inflated, inequilateral; beaks but little
elevated; dorsal outline lightly curved; anterior end rounded;
base line curved, fuller behind the middle; posterior ridge low,
inclined to be double, ending in a blunt point or a feeble bian-
gulation about on the median line; dorsal slope obliquely trun-
cate; surface with delicate, concentric sculpture; epidermis
brownish-green ; teeth lamellar and delicate.

Length 56, height 33, diam. 19 mm.

Environs of Bagdad?

Unio bagdadensis Bourcurcnat, Test. Nov. Saulc., 1852, p.
30; Cat. Rais., 1853, p. 78, pl. Iv, figs. 4-6—KosBeEvt, Icon.
new ed., XVIII, 1912, p. 64, fig. 2685.

Margaron (Unio) bagdadensis Lea, Syn., 1870, p. 46.

Nodularia bagdadensis Stmpson, Syn., 1900, p. 822.

More delicate and compressed than N. nilotica and having
decidedly lamellar pseudocardinals.

This appears from the figures and descriptions to be a mem-
ber of the egyptiaca group of Nodularia. It is possible that
it came from Asia Minor, but more likely that it is an African
species. The Unio eucyphus of Bourguignat, which he credits
to this region, is believed by Lea to be the U. egyptiacus of
Cailliaud, and I agree with him. This may be merely a pecu-
liar form of the same thing.

1024 NODULARIA

NODULARIA CUARBGNNIERI (Bourguignat).

Shell solid, more or less gaping in front or behind or both,
inflated, irregularly elliptical; beaks moderately full and high,
rugosely sculptured ; hinge line curved; anterior end rounded ;
base line curved, fuller behind the middle; dorsal slope sub-
- truncate above, rounded below into the posterior point of the
shell; posterior ridge full, widely rounded, ending in a round-
ed point below the median line; surface lightly, concentrically,
sculptured ; epidermis varying from dark olive to chestnut or
reddish-brown; pseudocardinals rather short and strong, rag-
ged; laterals heavy, curved; nacre whitish or flesh-colored.

Length 77, height 48, diam. 39 mm.

Length 64, height 39, diam. 31 mm.

Length 64, height 43, diam. 29 mm.

Lake Tanganyika.

Unio charbonnieri BourcuicNat, Un. and Ir. Tan., 1886, p. 9.
—Icon. Mal. Tan., 1888, pl. xx, figs. 1, 2—GERMAIN, Moll.
L. Tan. 1008.9: 72:

Unio coulboisi BourcuicNat, Un. and Ir. Tan., 1886, p. 12;
Icon. Mal. Tan., 1888, pl. xx, figs. 3, 4.

Unio dromauxi Bourcuicnat, Un. and Ir. Tan., 1886, p. 17;
Icon. Mal. Tan., 1888, pl. xxui, figs. 1, 2.

Nodularia nilotica (part), SIMPSON, Syn., 1900, p. 821.
Probably only a form of NV. nilotica. It seems to be solider,

more inflated, and to be somewhat more decidedly sulcate, as

well as rather darker colored. It is more evenly elliptical than

N. randabeli, and has smaller umbones. The latter may be

only a diseased form of this species.

Germain, (1. c.), considers charbonnieri a valid species and
a Unio.

NopULARIA RANDABELI (Bourguignat).

Shell irregularly rhomboid, inflated, rather solid, inequilat-
eral; beaks high and full, elegantly sculptured with rough-
ened, zigzag-radial ridges ; hinge line nearly straight ; anterior
end considerably narrowed and rounded; base line nearly
straight, full behind the middle; dorsal slope almost winged

NODULARIA 1025

above, decidedly and somewhat obliquely truncate behind ; pos-
terior ridge quite high, broadly rounded, ending at the -base of
the sheli in a widely rounded or subbiangulate termination ;
surface with fine concentric striz, subshining ; epidermis olive,
with very numerous fine rays; pseudocardinals compressed,
ragged; laterals nearly straight; nacre white and splendidly
iridescent.

Length 57, height 35, diam. 31 mm.

Lake ‘Tanganyika.
Unio randabeh Bourcuicnat, Un, and Ir. Tan., 1886, p. 22;

Icon. Mal. Tan., 1888, pl. xx1, figs. 3. 4.
Nodularia randabeli Simpson, Syn., 1900, p. 822.

The shell figured appears to be somewhat diseased. It dif-
fers from JN. nilotica in its greater degree of inflation, the
fuller beaks and more brilliant nacre.

NODULARIA ESSOENSIS (Chaper).

Shell rather large, subinflated, slightly inequilateral, thin,
subelliptical or subrhomboid; beaks high and full, their sculp-
ture consisting of delicate, subnodulous, zigzag-radial ridges,
with indications of similar sculpture on the dorsal slope; sur-
face with irregular growth lines and faint indications of radial
sculpture; hinge line slightly curved; anterior end narrowed
and rounded; base line curved, quite full at or behind the
middle ; posterior slope almost elevated into a wing and rather
squarely truncated behind; posterior ridge full, rounded, end-
ing about on the median line; epidermis brownish-green, feebly
rayed, dull; teeth lamellar, delicate ; nacre bluish.

Length 75, height 53, diam. 35 mm.

Assini, west coast of Africa.

Unio essoensis CHAPER, Bull. Soc. Zool. Fr., X, 1885, p. 481,

pl. x1, figs. 8, 9.

Nodularia essoensis Simpson, Syn., 1900, p. 822.

This seems to be a larger species than N. egyptiaca, to which
it is very closely related. It is duller colored and less rayed
than that species and the surface is rougher. There is a fine
young shell of this species in the National Museum from the
Morelet collection taken at the type locality.

1026 NODULARIA

Var. minor Germain.

“Shell thin, light, with a brilliant chestnut epidermis orna-
mented with narrow, emerald green rays, more numerous pos-
teriorly. ‘The beaks sometimes have strong tubercles; nacre
orange, very iridescent.

Tjength 26-32, height 20-23, diam. 11-15 mm.” (Germain).

Type locality, Le Kanem, eastern Tchad.
Unio (Nodularia) essoensis var. minor GERMAIN, Bull. Mus.

Hist;, INat:, 1906, p172.

NoDULARIA DECAMPSIANA (Wattebled).

Shell rather short, irregularly elliptical, convex, rather thin,
somewhat inequilateral ; beaks but slightly elevated ; hinge line
curved; anterior end evenly rounded; base line curved, a little
fuller behind the middle; posterior ridge moderately elevated,
inclined to be double, ending a little below the median line;
dorsat slope obliquely subtruncate; surface sculptured with
rather fine, concentric ridges; epidermis brownish-black ; teeth
compressed ; pseudocardinals sublamellar; muscle scars well
marked; nacre purplish, rather brilliant.

Length 4o, height 26, diam. 16 mm.

Western Soudan.

Unio decampsianus WaAtTTEBLED, J. de Conch., XXXII, 1884,
pet 32) plcvin; fies sr.

Nodularia decampsiana SIMPSON, Syn., 1900, p. 822.

Unio campsianus Parren, Conch. Sam., III, 1890, p. 147.

This species probably belongs in this group. It appears to
be a little solider than N. @gvptiaca, is more compressed, has
apparently decided concentric sculpture and purplish nacre.

NopULARIA BELLAMYI (Jousseaume).

Shell rather small, nearly regularly obovate, being slightly
narrowed in front, inequilateral, thin and fragile, inflated;
beaks full and high, sculptured with fine, broken, granular
wrinkles, this sculpture extending more or less over the shell,
especially on the ends of it; epidermis yellowish-gray with a

NODULARIA 1027

blackish or brownish band near the border; teeth lamellar;
nacre bluish-white.

Length 33, height 20, diam. 15 mm.

Faraba, on the Niger; Upper Senegal.

Pharaonia bellamyi JouSSEAUME, Bull. Soc. Zool. Fr., XI, 1886,
piso, pl xin: figs. 7a. 7D:
Nodularia bellamy: Stimpson, Syn., 1900, p. 822.

The figure shows this species to be almost evenly obovate,
being slightly narrower in front where it is rounded, and the
somewhat broader posterior end is almost evenly rounded. The
posterior ridge is rounded or feebly double and the surface of
the shell seems to be more or less granularly sculptured, the
granules being arranged in broken lines. Its form and frail
structure should distinguish it from allied species. The spec-
imen described and figured may be young.

NoODULARIA RENEA (Jousseaume).

Shell slightly obovate, somewhat inflated, thin, inequilateral ;
beaks moderately full and high; the umbonal region and sur-
face generally sculptured with fine, zigzag-radial, granulous
ridges; anterior end rounded, slightly angled above; base
lightly curved, fuller and rounded behind the middle; dorsal
slope obliquely subtruncated; posterior termination rounded ;
posterior ridge widely rounded; epidermis yellowish-brown ;
teeth delicate, lamellar; nacre bluish-white, somewhat irides-
cent.

Length 29, height 17, diam. It mm.

Niger at Kayon; Senegal River; Upper Senegal.

Reneus reneus JOUSSEAUME, Bull. Soc. Zool. Fr., XI, 1886, p.

482, pl. xu, figs. 4a, 4b.

Reneus faidherbi JousskAUME, Bull. Soc. Zool. Fr., XI, 1886,

p. 483, pl. x11, figs. 5, 5a.

Nodularia renea SIMPSON, Syn., 1900, p. 822.

Less high in proportion to length than N. bellamyi and the
basal outline is not so rounded. There is a shell and a left
valve in the National Museum collection from Morelet labeled
Unio faidherbi by him, which are feebly rayed and have but
little zigzag sculpture.

1028 NODULARIA

NoDULARIA LACOINI Germain.

“Shell elongate-oval, quite inflated, solid, opaque; dorsal
margin almost straight; anterior margin rounded, slightly an-
gulated above; ventral margin regularly convex; posterior re-
gion elongated, one and one-half to two times as long as the
anterior, with the dorsal edge quite sharp in young shells,
becoming obtuse in the adults; beaks prominent, often eroded,
and, in such cases, showing a white nacre, upon which the
apical sculpture is clearly defined; two cardinal teeth in the
right valve, relatively quite elongate, the lower higher than
the upper, separated by a deep groove; in the left valve a sin-
gle, high, stout, slightly compressed and finely sulcate car-
dinal; laterals two in the left valve, thin, compressed, parallel
and separated by a deep groove; in the right valve one, very
long, elevated and quite sharp; anterior muscular impressions
round and quite deep; posterior superficial. Epidermis pale
chestnut, sometimes tinged with yellow; lines of growth very
fine, but irregular; umbonal region tuberculate or with zig-
zag ridges; nacre iridescent, bluish or roseate.

Length 30-36. height 19-22, diam. 14-16 mm.’’ (Germain).

Type locality, Kanassarom, on the north-east side of Lake
Tchad. Also, Faguibine, Upper Senegal.

Unio (Nedularia) lacoimi GERMAIN, Bull. Mus. Hist. Nat.,
1905, p. 489; Mem. Soc. Zool. Fr., XIX, 1906, p. 237, pl.
Iv, figs. 11, 12; PAfrique Cent. Fran., 1907, p. 545-

“This species is excessively polymorphic both in form and
sculpture. Thus the following mutations can be distinguished,
which define themselves:

Var. ex-forma: elongata Germain.
curta Germain.
compressa Germain.

The sculpture of the shell consists, fundamentally, of quite
fine striae, which, in some examples, become strong, quite
heavy and very irregular. To this is added, sometimes, in the
umbonal region either tubercles or chevrons or occasionally
both.

NODULARIA 1029

Umio lacoimi resembles both Unio (Nodularia) @gyptiaca
Cailliaud, from which it differs by its more elliptical shape,
much longer cardinals, etc., and Unio (Nodularia) faidherbei
Jousseaume, from which it is distinguished by its less convex
shape, more anterior beaks, etc.”

Var. chudeawi Germain.

“Shell irregularly elongate-elliptic, very globosely inflated,
most so in the umbonal region; dorsal margin a little convex
and slightly oblique; ventral margin irregularly convex; an-
terior region short, somewhat rounded, cut away towards the
ventral margin; posterior region a little more than twice as
long as the anterior, terminating in a tapering point, somewhat
elevated; beaks very large, very prominent, tuberculate; dor-
sal edge blunt; the cardinal tooth in the left valve is very
stout, erect and cleft under the beak, and the two laterals are
long and unequal; anterior muscular impressions very deep,
posterior well marked, pallial line superficial.

Shell thick, slightly cretaceous, solid, with very heavy, very
irregular, elevated and very unequal strie; large wrinkled
tubercles on the beaks; nacre very iridescent, slightly tinged
with salmon.

Length 42, height 26.5, diam. 26 mm.” (Germain).

Type locality, N’Guigmi, Lake Tchad.

Unio (Nodularia) lacowmi var. chudeaut GERMAIN, Bull. Mus.

Hist. Nat., 1909, p. 541.

“This very beautiful shell, which I refer as a variety to Unio
lacoini Germain, is distinquished especially by its somewhat
cuneiform appearance, its very prominent beaks and its pecu-
liarly inflated form.”

NopuLARIA NGUIGMIENSIS Germain.

“Shell small, rounded-oval, very slightly subpentagonal,
moderately compressed; valves gaping at both ends; dorsal
margin straight, ventral margin very convex; antero-dorsal
and postero-dorsal angles subacute; anterior end rounded,
slightly cut away towards the base; posterior end one and

1030 NODULARIA

one-half times as long as the anterior, very high; beaks small,
somewhat incurved, very tuberculate; dorsal edge blunt; lig-
ament 4.75 mm. long; in the right valve, two strong cardinal
teeth, quite long (4 mm.), very stout, subequal and well curved
and a single, long lateral, at first straight, but curved in the
last third, high and sharp; in the left valve, one very large
cardinal, decidedly cleft under the beak, (the cleft part has the
form of a triangular tooth made of four denticles in the form
of triangular prisms united at the base), and two, long, ele-
vated laterals, the lower the larger ; anterior muscular impres-
sions irregularly oval, very deep, especially near the inner side,
posterior moderate, pallial line weak.

Shell solid, rather thick, slightly shining, coffee-colored, be-
coming yellowish-chestnut near the ventral margin; lines of
growth fine, quite regular, subequal; some chevrons and tu-
bercles well rounded and prominent near the beaks; nacre
white, a little milky, quite iridescent.

Length 18.5, height 14.5, diam. 9.5 mm.’ (Germain).

Type locality, N’Guigmi, Lake Tchad.

Unio (Nodularia) nguigmiensis GERMAIN, Bull. Mus. Nat.

Hist., 1909, p. 540, fig. 40.

This little species is quite distinct from Unio (Nodularia)
lacoimt Germain and its numerous varieties. It is easily dis-
tinguished by its round, subpentagonal form, more central

beaks, peculiar character of the hinge and, finally, by the more
solid shell.”

NopULARIA FOULADOUGOUENSIS (Jousseaume).

Shell irregularly elliptical, somewhat inflated, inequilateral,
subsolid; beaks but slightly full or elevated; anterior end
rounded, decidedly cut away below; base lightly curved, quite
full behind the middle, behind this inflation it is obliquely trun-
cated to the posterior point; dorsal outline a little arched ;
dorsal slope obliquely subtruncated; posterior ridge rounded,
ending behind in a somewhat drawn out, but blunt, point about
‘on the median line; surface with granulous, somewhat zigzag-

NODULARIA IO31

ged growth lines; epidermis yellowish-brown with a few faint
rays; teeth compressed, lamellar; nacre bluish-white.

Length 26, height 16, diam. 10 mm.

Fouladougou, Niger; Upper Senegal.

Reneus fouladougouensis JoussrAuME, Bull. Soc. Zool. Fr.,

XI, 1886, p. 485, pl. x11, figs. 6, 6a.

Nodularia fouladougouensis SIMPSON, Syn., 1900, p. 823.

It is quite difficult to be sure, from the figures and often
imperfect descriptions, of the validity of a number of the so-
called species of this group. This seems to be very close to
N. renea, but it is more angularly full at the posterior base
and more drawn out behind than that species. In outline it is
much like Lampsilis vanuxemensis of the Southeastern United
States.

NopuLARIA GABONENSIS (Kuster).

Shell rhomboid elliptical, rather inflated, thin, inequilateral ;
beaks high and full, with zigzag, subnodulous sculpture; pos-
terior ridge full near the beaks, rounded, fading out below and
ending below the median line; anterior end a little narrowed,
rounded ; base line well curved, slightly fuller behind the mid-
dle; hinge line lightly curved; dorsal slope obliquely subtrun-
cate; surface nearly smooth, with a few wrinkles on the dor-
sal slope and faint indications of corrugations on the anterior
end ; epidermis ashy-greenish or yellowish-green, lightly rayed,
somewhat shining; teeth delicate and lamellar; beak cavities
well impressed; nacre bluish or whitish, somewhat iridescent.

Length 38, height 23, diam. 16 mm.

Gaboon River, West Africa.

Unio gabonensis Kuster, Conch, Cab. Unio, 1862, p. 291, pl.

XCVII, fig. 7.

Margaren (Unio) gabonensis Lea, Syn., 1870, p. 47.
Nodularia gabonensis Stwpson, Syn., 1900, p. 823.

There is a shell in the Lea collection named Unio gabonen-
sis, from Isabon, that exactly agrees with the form and di-
mension of Kuster’s figure, but is not quite so brightly colored
or so decidedly rayed. In outline it is not so angular as N.
equatoria.

1032 NODULARIA

NODULARIA AQUATORIA (Morelet).

Shell irregularly obovate, subinflated, rather thin, inequi-
lateral; beaks full and high, their sculpture consisting of a few
nodules and zigzag-radial ridges; hinge line nearly straight;
anterior end narrowed and rounded, cut away a little below;
base line nearly straight to behind the middle, where it is full
and almost forms an angle, rising in an oblique direction to
the produced posterior- point; dorsal slope obliquely truncate;
posterior ridge full, rounded, ending about on the median
line; surface with strong growth lines in front, nearly smooth
on the center of the disk, ashy-green or brownish-green, fee-
bly rayed; epidermis either smooth or roughened; teeth deli-
cate, lamellar; nacre bluish-white.

Length 55, height 32, diam. 23 mm.

Length 48, height 31, diam. 20 mm.

Length 28, height 20, diam. 13 mm.

Congo drainage.

Unio equatorius Morrie, Jl. de Conch., XXXIII, 1885, p.
ai pl asics. 9:

Nodularia equitoria SIMPSON, Syn., 1900, p. 823.

Umi landanensis SCHEPMAN, Notes Leyden Mus., VIII, 1891,
p. 113, pl. vu, figs. 3a, 3b.—GrERMAIN, Bull. Mus. Nat. Hist.,
1907, p. 430, fig. 20.

A number of specimens are before me from different local-
ities in the Congo basin showing much variation in size and
form. ‘Two lots are from Leopoldville, each showing decided
variation among the individuals of each lot. It may be well
to retain the name /andanensis in a varietal sense for the
smaller, rougher forms. | have examined gravid females of
the e@quataria and found the inner gills only filled with em-
bryos. forming smooth, even pads, like those of the Uniones of

South America.
3y an error the name @quatoria was misspelled in the Synop-
sis.

NODULARIA ELEGANS (Rochebrune).
“Shell elliptic-oval, quite inflated, well rounded anteriorly,

with the posterior region almost twice as long as the anterior.
The shell, which is quite strongly anodonti-form in appearance.

NODUI,ARIA 1033

is thin, of an olive-green, a little yellowish towards the beaks
and anterior margin, with a few, narrow, emerald-green rays.
Ines of growth not strong, irregular, slightly lamellose to-
wards the basal margin. Nacre rose-tinted, slightly iridescent.

Length 50, height, at 15 mm. from the beaks, 25.5, under
the beaks 23, diam 17.5 mm.” (Germain).

Type locality, The Congo.

Zairia elegans ROCHEBRUNE, Bull. Soc. Mal. Fr., III, 1886, p.

I12.— SIMPSON, Syn., 1900, p. 862.

Unio (Nodularia) roubaudi GERMAIN, Bull. Mus. Hist. Nat.,

XX, 1907, p. 420, fig. 28.

The new name proposed by Germain, (1. c.), is unnecessary
in Nodularia,

The original description not being accessible at the present
time, I have copied that given by Germain. That author fur-
ther remarks that the species resembles the U. landanensis
Schepman very closely, that being a shell of practically the
same character, but of a more elongated form with the basal
margin more oblique, but it is probable that they are the same
species.

NopDULARIA GEAYI Germain.

“Shell elongate-oval, slightly subcuneiform, somewhat in-
flated, the greatest width posteriorly ; valves gaping anteriorly ;
anterior end rounded, sloping towards the base; posterior re-
gion more than two and one-half times as long as the anterior,
terminating in a slight, post-basal point ; dorsal edge blunt ; dor-
sal margin subconvex, ascending obliquely to the postero-dor-
sal angle, which is not strong and from which it merges into
the convexly descending posterior margin; ventral margin
convex, slightly subsinuous in the middle; beaks small, not
prominent, much eroded; anterior ligament thin, scarcely pro-
jecting, 7 mm. long; posterior ligament not very strong, of a
rather dull reddish-brown, 12 mm. long. Hinge weak; in the
right valve, two, short, rather low, subequal cardinals and one
long, straight, not prominent, thin and sharp lateral; in the
left valve a single, weak, low, subtriangular cardinal and two,
thin, rather long, nearly straight laterals, the lower slightly the

1034 NODULARTA

higher. Posterior muscular impressions faint, round; anterior
large, deep; pallial impression visible the whole length of the
shell, but not strong.

Shell light, thin, fragile; epidermis of a deep brown and not
very bright, more or less eroded towards the beaks; lines of
growth quite fine and regular. Nacre bluish, slightly irides-
cent, lead-color under the beaks.

The young have the posterior region more expanded, owing
to the ventral margin being more constricted in the middle,
and the posterior extremity is nearer the median line. The
shell is brighter and the lines of growth are very regular.

Length 54, height at 18 mm. from the beaks 30, length of
anterior region 14.5, of posterior region 41, diam. 17 mm.”
(Germain).

Type locality, Madagascar.

Unio (Nodularia) geayi GERMAIN, Bull. Mus. Hist. Nat., 1911,

DP: 137. Pl. T, MISS. AO, 7

“The Unio geayi Germain has affinities on one hand with the
species of India belonging to the subgenus Lamellidens and,
on the other, with the African species of Nodularia. Compar-
ed with the Lamellidens it reminds one, by its thin shell and
hinge characters of Unio (Lamellidens) marginalis Lamarck
from India and Cevlon; Unio (Lamellidens) thwaitesti Lea of
Ceylon, etc.

Compared with the African species, it is closely related
to the Nodularie of the equatorial regions, (Unio (Nodularia)
equatorialis Morelet; gaillardi Germain, etc.), by reason of
thin, light shell, character of the nacre and reduction of the
hinge.”

NopULARIA HOREI (E. A. Smith).

Shell subrhomboid, slightly inequilateral, rather thin, com-
pressed; beaks full and high, with zigzag corrugations, and
having radial plications in front of and behind them, the rest
of the surface concentrically striate ; posterior ridge low, round-
ed or semi-double, ending bluntly behind below the median
line; base curved; anterior end rounded; dorsal slope almost

NODULARIA 1035

squarely subtruncate ; teeth thin, lamellar ; scars shallow ; nacre
white pearly.
Length 25, height 16.5, diam. 9.5 mm.
Lake Tanganyika.
Unio horei E. A. Smiru, Ann. and Mag., VI, 1880, p. 429;
Pry Zcok. Soc,Lond. 1881; p.200,,pl: xx xiv,, fig: 37.
Grandidieria horei BourcuiGnat, Bull. Soc. Mal. Fr., II, 1885,
pu:6:
Nodularia horei Stimpson, Syn., 1900, p. 823.
Smith believes that the shell from which his description
and figure were made is young. It is quite thin and com-
pressed and has an almost square subtruncation behind.

NopULARIA BORELLIT (Ancey).

Shell almost regularly obovate, greatly inflated; subsolid,
somewhat inequilateral, beaks only slightly elevated; anterior
end narrowed and rounded, slightly cut away below; base al-
most evenly curved, but a little fuller behind the middle; out-
line of dorsal slope rather full, almost squarely subtruncated
behind ; anterior and posterior ends undulately rugose ; epider-
mis dirty brown; hinge lightly arcuate; nacre brilliant, irides-
cent.

Length 29, height 19, diam. 16.5 mm.

Lake Nyassa and vicinity.

Umo borellu Ancry, Bull. Soc. Zool. Fr., VII, 1894, p. 226,

fig. 2.

Nodularia borellu Stmpson, Syn., 1900, p. 823.

A small, inflated species with the umbones, the anterior and
posterior ends of the shell corrugately wrinkled, dirty fuscous
epidermis, and brilliant iridescent nacre.

NODULARIA EMINI (von Martens).

Shell subrhomboid, subinflated, subsolid, inequilateral ; beaks
full and high, but not elongated; posterior ridge well devel-
oped, rather narrowly rounded above, fading out somewhat
below, ending near the base; hinge line slightly sinuous; ante-
rior end angled above, rounded and cut away a little below;
base line curved; dorsal slope obliquely truncate, the lower

1036 NODULARTA

posterior part of the shell widely rounded; surface with mod-
erate growth lines; epidermis yellowish-brown, the umbones
white, marked with orange-red; nacre whitish, tinted reddish.
Length 43, height 25, diam. 20 mm.
Victoria Nyanza.
Unio emint VON Martens, Besch. Deuts. Ost-Af., 1897, p. 224,
pl. vu, fig. 14.
Nodularia enuini Simpson, Syn., 1900, p. 823.
The distinguishing characters of this species seem to be its
rather short, rhomboid form and the somewhat sinuous hinge
plate. The color of the beaks and umbonal region is peculiar.

NepvulLARTA BOHMI (von Martens).

Shell rather large for a member of the group, long, rhom-
boid, somewhat inflated and solid, quite inequilateral; beaks
large, high and full; posterior ridge only moderately devel-
oped, rounded, inclined to be double below, ending in a feeble
biangulation near the base of the shell; hinge line strongly
curved; anterior end rounded, lightly angled above; base line
faintly curved; dorsal slope obliquely subtruncate; surface
with delicate, concentric sculpture, brownish; pseudocardinals |
quite strong, subcompressed, ragged; laterals decidedly curv-
ed, lamellar; anterior muscle scars well impressed ; beak cavi-
ties well excavated; nacre whitish, iridescent.

Length 62, height 37.5, diam. 27 mm.

Lake Tanganyika. ;

Unio bohmu von Martens, Besch. Deuts. Ost-Af., 1897, p.

223 ho VIL, 11S. 9.

Nodularia bohmi Stmpson, Syn., 1900, p. 823.

A large, somewhat ponderous member of the egyptiaca

group, considerably inflated and long rhomboid in outline.

NopULARIA AMBIFARIA (von Martens).

Shell rather small, subquadrate or subrhomboid, convex,
solid, somewhat inequilateral; beaks only moderately full or
high; posterior ridge not elevated, rounded; hinge line nearly
straight; anterior end rounded and angled above; base line
straight and parallel with the dorsal outline; posterior end

NODULARIA 1037

almost squarely subtruncate above, bluntly pointed below the
median line; surface sculptured with V-shaped ridges and
strong subradial folds on the dorsal slope, epidermis brown-
ish-green with green rays, which are stronger on the posterior
end; hinge teeth sublamellar, but strong.

Dar-es-Ssalam, East Africa.

Unio ambifarius VoN Martens, Besch. Deuts. Ost-Af., 1897,

p. 225, pl. vit, fig. 20.

Nodularia ambifaria SIMPSON, Syn., 1900, p. 823.

The shell of this species is almost regularly long quadrate,
the dorsal and ventral outlines being parallel and the poste-
rior end nearly squarely subtruncate above. It seems to be
covered with delicate, zigzag sculpture, and has strong folds
on the dorsal slope. It is strongly rayed for a member of this
group.

NopULARIA LECHAPTOISI (Ancey).

Shell subelliptical, subinflated, slightly gaping in front, and
solid; beaks apparently rather low, dorsal outline ‘curved ;
anterior end rounded, very slightly cut away below; base line
almost evenly curved; dorsal slope obliquely subtruncate ; pos-
terior ridge rounded, ending below the median line in a round-
ed point; upper part of the anterior and posterior ends sculp-
tured with strong wrinkles; epidermis fuscous, blackish be-
hind ; beaks roughened ; nacre pale salmon.

Length 38, height 21.5, diam. 17 mm.

Shire River, Lake Nyassa.

Unie lechaptoisi ANcry, Bull. Soc. Zool. Fr., VII, 1894, p. 228,

fig. 3.

Nodularia lechaptoisi Simpson, Syn., 1900, p. 823.

More nearly elliptical than N. borellu and having different

nacre.

NODULARIA LIEDERI (von Martens).

Shell decidedly rhomboid, somewhat elongated, inequilat-
eral, solid, subinflated: beaks moderately full and high with
two divergent rows of tubercles; posterior ridge well develop-
ed, subangular, ending in a blunt point below the median line ;

1038 NODULARIA

hinge line nearly straight; anterior end rounded but consider-
ably cut away below; base line almost straight and subparallel
with the hinge line to behind the middle, where it is inflated ;
dorsal slope decidedly and obliquely truncate ; pseudocardinals
compressed, strong; nacre bluish, reddish in the cavities.
Length 33, height 17, diam. Io mm.
Lake Nyassa.
Unio liederi voN Marrens, Besch. Deuts. Ost-Af., 1897, p.
226, pl. vii, fig. 19.
Nodularia liederi SIMPSON, Syn., 1900, p. 824.

A rather elongated species, which does not seem to have
any very striking characters, yet it does not appear to be refer-
able to any other species.

Species INCERTA SEDIS

NoOpDULARIA DUPONTI (Rochebrune).

Reneus duponti JoussEAUME, Bull. Soc. Zool. Fr., XL, 1881,
p. 481.

Unio duponti RocHEBRUNE, Bull. Soc. Philom., VI, 1882, p.
34; Bull. Mus. Hist. Nat., 1904, p. 258.—GrERMAIN, Bull.
Mus. Hist. Nat., 1906, p. 304.

Parreysia duponti (part) Stmpson, Syn., 1900, p. 846.

Type locality, Backoy River, Senegal.
In the Synopsis this species was united with the U. duponti

of Bourguignat. But both Rochebrune and Germain (1. c.),

consider it distinct.
The original description is not now accessible to me.

NopvutARIA CHIvotTrt Germain.

“Shell small, quite regularly oval, much compressed ; valves
thin, but quite solid, slightly gaping anteriorly ; dorsal margin
regularly subconvex; ventral margin very regularly and de-
cidedly convex; anterior end rounded, slightly sloping to-
wards the base; hinder end one and one-half times longer than
the anterior, ending in a slightly truncated point ; beaks eroded.

not very prominent, rather large and obtuse ; dorsal edge not
very acute; in the right valve, two medium-sized cardinal

teeth, the lower more elevated than the upper, almost smooth,
slightly crenulated at the anterior extremity, the upper a little

NODUI,ARIA 1039

longer, less high, thinner ; lateral tooth long, thin, elevated ; in
the left valve, one, subtriangular, rather elevated cardinal tooth
and two very long, thin, quite elevated laterals, the lower
higher than the upper: anterior muscle impressions moderate,
posterior very superficial ; ligament very short, brilliant chest-
nut-color.

pidermis deep chestnut-color, passing into blackish-brown
anteriorly ; lines of growth fine, quite regular, very crowded,
finer and more irregular posteriorly, and ornamented, besides,
with more or less prominent folds radiating from the beaks.
These folds are only found on the umbonal region, where
they surround, so to speak, the beaks ; they are more developed
posteriorly and in the centre and anteriorly become projecting
granules. This sculpture of the shell is, in every way, compar-
able with that of the Unios of the Victoria-Nyanza. Nacre
very iridescent, quite deep Prussian blue.

Length 31, height at 10.5 mm. from the beaks 19, diam. 10
mm.” (Germain).

Type locality, Le Mamoun, Country of Senoussi.
Unio (Nodularia) chivoti GERMAIN, Bull. Mus. Hist. Nat.,

1007, p06.) Att. Cent. Franz, 1907, p. 542, pl: v, fig. 23:

NopuLARIA BANGORANENSIS Germain.

“Shell small, elongate-oval, rather convex; gaping consid-
erably in front, very slightly posteriorly ; dorsal margin regu-
larly convex; ventral margin very convex; anterior margin
rounded, slightly curved in towards the base; posterior end
not quite one and one-half times as long as the anterior, ter-
minating in a small point; beaks slightly obtuse, a little com-
pressed; dorsal edge very blunt; hinge having in the right
valve, two, not very long, cardinal teeth, the lower subtrian-
gular, much elevated, much more so than the upper, which is
very slight and a long, rather low lateral; in the left valve,
one rather high cardina! with two projecting points, the first,
very sharp, almost under the beaks, the other longer and blunt-
er near the antero-dorsal angle, and two very long laterals;
anterior muscular impressions deep, posterior very superfi-

1040 NODULARIA

cial ; ligament short, rather stout. Epidermis very deep brown,

much eroded about the beaks; lines of growth fine, close and

irregular; nache bluish, sometimes salmon-tinted, quite irides-
cent.

Length 23-26, height 13.5 (at 5.5 mm. from the beaks)—
21.5 (at 12 mm. from the beaks), diam. 10-14 mm.” (Ger-
main).

Type locality, Le Bangoran, affluent of the Chari, Country of
Senoussi.

Unio (Nodularia) bangoranensis GERMAIN, Bull. Mus. Nat.
Hist... 1907.0 pix60 = V-Ate> Cente Frans “16072 "p54 saan we
fig 22:

“This species resembles in shape U. chizvoli, but differs by
its more truncate form, the posterior region being notably
more expanded; by its more inflated shell, gaping at both
ends (in chivoti only the anterior end is gaping) ; and espe-
cially by the entirely different sculpture of the surface.”

NopuLARIA KGSHLERI Germain.

“Shell quite large, elongated-suboval, very globose; valves
slightly gaping posteriorly, much swollen and with the great-
est convexity near the dorsal edge; dorsal margin straight ;
ventral margin regularly convex, sloping upwards slightly
anteriorly, almost parallel with the dorsal margin; antero-
dorsal and postero-dorsal angles well marked; anterior end
short and rounded; posterior region a little more than twice
as long as the anterior; beaks large, prominent, incurved and
with strong, zigzag ridges; dorsal edge blunt; ligament 12.5
mm. long; in the right valve two strong cardinal teeth, the
lower higher and sharper than the upper and a very long,
straight, sharp lateral; in the left, a large cardinal tooth, faint-
ly serrate, and two, subequal, long, thin and sharp laterals;
anterior muscular impressions deep, posterior superficial; pal-
lial line very faint.

Shell moderately thick, very solid, dark chestnut-colored,
greenish towards the beaks, with a yellowish zone well marked,
near the ventral border. Sculpture consisting of very irregu-

NODULARIA 1041

lar, strong, plicate lines of growth and in the umbonal region
strong, zigzag ridges, tuberculate and very irregular. Nacre
Prussian blue, very iridescent, sometimes salmon-tinted to-
wards the ventral margin.

Length 40, height 26, diam. 21 mm.” (Germain).

Type locality, Swamps of Kollangui, French Guinea.

Unio (Nodularia) kehleri GermMatn, Bull. Mus. Hist. Nat.,

1909, p. 541, pl. vit, figs. 43, 44, 47.

“This very beautiful species cannot be compared with any
African Unio now known. It resembles a little, by its globose
form and zigzag sculpture the Unios of Lake Victoria-Nyanza,
such as Unio hypsiprimus Martens and Unio hautteceuri
Bourguignat. Its sculpture, moreover, is very similar to that
of Spatha vignoni Bernardi.”

NopuLARIA GAILLARDI Germain.

“Shell quite small, very elongate-elliptic, much compressed ;
thin, light, slightly gaping posteriorly ; dorsal margin subcon-
vex, slightly oblique; ventral margin regularly rounded, almost
parallel to the dorsal margin; antero-dorsal angle well marked ;
postero-dorsal angle slight; anterior margin short, rounded,
cut away towards the base; posterior region much developed,
at least three times as long as the anterior, posterior end
elongated, submedian, somewhat pointed; beaks very small,
not prominent; dorsal edge very blunt; ligament thin, 15
mm. long; hinge not very strong; in the right valve, two short
cardinals, rather high, crenate, the lower notably higher and
stronger and a single, long, subconvex, very thin lateral; in
the left valve, one very feeble, low cardinal and two subequal,
week, thin laterals; muscular impressions faint.

Shell thin, rather fragile, light; epidermis a clear chestnut,
slightly tinged with gray; lines of growth fine and irregular;
nacre violet, very iridescent.

Length 42, height 20.5 at 9.5 from the beaks, diam. 10
mm.” (Germain).

Type locality, Senegal.

Unio (Nodularia) gaillardi Germain, Bull. Mus. Hist. Nat.,

1909, p. 542, pl. viii, figs. 41, 42.

1042 NODULARIA

“This interesting species, collected by Verreaux in 1845,
inhabits Senegal. The exact locality, where it was found, is
unknown to me.”

NopDULARIA ERLANGERI Kobelt.

“Shell rather small, oval, shortly rounded in front, subros-
trate posteriorly, rather solid, but not heavy, very coarsely
striate, scarcely shining, olive-brown. Dorsal and ventral mar-
gins nearly parallel, slightly curved, the latter sometimes a
little subsinuate posteriorly. Beaks anterior, situated at 1/4
the length, not prominent, greatly eroded in the specimens
examined. Cardinal teeth of the left valve compressed, coni-
cal, the anterior the larger, separated by a sublateral pit;
cardinal tooth of the right valve obtusely conical, lightly crenu-
late, separated from the margin by a deep groove; laterals
thin, sharp, and at a decided angle with the cardinals, from
which they are separated by a long interdentum; anterior
muscular impressions distinct, tripartite, the posterior super-
ficial; callus humeralis distinct, continued almost to the pos-
terior end; nacre suffused with brown in the center.

Length 40, alt. 22, diam. 15 mm.” (Kobelt).

Type locality, Somaliland.

Unio (Nodularia) erlangeri Konryt, Abh. Senck. Nat. Ges.,

32, 1909, p. 49, pl. vu, fig. 8.

“Germain, to whom I sent the types for comparison with
Bourguignat’s types, was unable to refer them to any of the
described species. He writes: “The Unio is unknown to me.
It resembles in general appearance some examples of Unio
plicatulus Lea from the Cape, but is quite distinct by its lines
of growth. But your shell belongs to the group of Unio
abadianus Bgt., and is very close to Unio hamyi Bgt. It dif-
fers principally by being more elevated at the postero-dorsal
angle. This is the result of the comparison that I have made
with the types of Bourguignat’.”

NopULARIA SUBNIGRA Preston.

“Shell oblong-ovate, covered with a dark brown periostra-
cum, smooth centrally, but becoming laminiferous towards the
margins, especially posteriorly; umboes moderately small,

NODULARIA 1043

situated subcentrally ; dorsal margin slightly arched; ventral
margin gently curved; anterior side flattened, bluntly rounded ;
posterior side very obtusely angled; left valve bearing a car-
dinal, jagged lamelliform tooth; anterior teeth wedge-shaped,
with jagged edges; posterior teeth fine, elongate, smooth; in-
terior of shell pale flesh-color, changing towards the anterior
and posterior margins to iridescent livid blue.

Pons 31-5, lati 4o mm: “(Preston’).

Type locality, lower Belgian Congo.
Unio (Nodularia) submigra Preston, Ann. Mag. Nat. Hist.,

(8), 1V, 1960;-p: 8g; pl..tv, fig. 5-

NopuLARIA VERRUCOSA Haas.

“Shell elongated, low, rather solid. Anterior end short,
semicircular; ventral margin at first horizontal, then bent up-
wards in an obtuse angle to the posterior end; posterior mar-
gin at first horizontal, then oblique; posterior ridge distinct,
somewhat biangulate. Beaks slightly prominent, quite inflated,
situated at 29/100 of the total length. Beak sculpture con-
sisting of wart-like elevations, which are connected by low
curves to concentric, wavy wrinkles, which cover nearly the
whole shell; vertical under the beaks and on the areola, the
wrinkles become zigzag-shaped, then extend almost straight to
the posterior ridge, where they bend upwards and extend over
the posterior slope, gradually becoming weaker, towards the
beaks, which, however, only the upper ones reach as low
striz. As a whole, the lower area appears to be quite smooth,
while the areola is entirely covered with the wavy wrinkles,
the warts being very close to each other and almost confluent.
Ligament weak. Hinge delicate; the cardinal tooth of the
right valve is lamelliform, striate above; both of the cardinals
of the left valve are also lamelliform, the anterior twice as
long as the posterior, which stands under the beak; the lat-
erals begin directly behind the cardinals, are long and some-
what bent in the middle. The cardinal teeth and the anterior
half of the laterals are parallel with the axis of the shell.
Anterior muscular impressions deep; posterior shallow. Nacre

1044 NODULARIA

bluish-white. Epidermis dark green, lighter towards the
margins, eroded on the beaks.
Length 31, height 16, diam. 11 mm.” (Haas).
Type locality, The Nile.
Nodularia verrucosa Haas, Nachr. Deutsch. Mal. Ges., 1910,
Pp. 99.

The following species are unfigured, and it is impossible
to make out what they are. According to von Martens they
belong in this group. I have not seen any of them.

NopULARIA CALATHUS (Bourguignat).

Unio calathus Bourcuicnat, Esp. Ouk. et Tan., 1885, p. 23-
Nodularia calathus SIMPSON, Syn., 1900, p. 824.
Tanganyika.

NoDULARIA BAKOYI (Rochebrune).

Unio bakoyi ROCHEBRUNE, Bull. Soc. Phil., 7th ser., VI, 1882,

p. 33.—GERMAIN, J]. de Conch., LVI, 1908, p. 112.
Nodularia bakoyi Simpson, Syn., 1900, p. 824.

Bakoy, Upper Senegal.

Germain, (1. c.), states that this is probably the same as
the subsequently described U. faidherbei Jouss. He says,
“the author’s type, which is in the Museum of Paris, is a
shell 35 mm. long, 19 mm. high at 11.5 mm. from the beaks
and 13 mm. in diameter, presenting all of the principal char-
acters of that species and especially. the same peculiar convex-
ity of the valves with the greatest diameter near the beaks.
Only the dorsal margin is less elevated, which causes the shell
to appear a little more elongated.”

NoDULARIA RATIDOTA (Charmes).

Unio ratidotus CHArMES, Bull. Soc. Mal. Fr., II, 1885, p. 166.
Nodularia radiota SIMPSON, Syn., 1900, p. 824.
Central Africa. .

NopuULARIA JULIANI (Rang).

Unio juliani Ranc, Nouv. Ann. Mus., 1835, p. 300.
Nodularia juliani Stmpson, Syn., 1900, p. 248.
Senegal.

NODULARIA 1045

_ NODULARIA POIRIERI (Rochebrune).

Type locality, The Congo.
Zairia poirieri ROCHEBRUNE, Bull. Soc. Mal. Fr., III, 1806, p.
II.—SIMPSON, Syn., 1900, p. 862.

Nodularia ARANEOSA (Rochebrune).

Type locality, The Congo.
_ Zairia araneosa ROCHEBRUNE, Bull. Soc. Mal. Fr., III, 1886,
p- 11.—Srmpson, Syn., 1900, p. 862.

NopuLaRIA SoRDIDA (Rochebrune).

Type locality, The Congo.
Zairia sordida ROCHEBRUNE, Bull. Soc. Mal. Fr., III, 1886, p.
13.—SIMPSON, Syn., 1900, p. 862.

NODULARIA DISCIFORMIS (Rochebrune).

Type locality, The Congo.
Zairia disciformis ROCHEBRUNE, Bull. Soc. Mal. Fr., IIT, 1886,
p. 10.—Simpson, Syn., 1900, p. 862.

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