t^^l

154 TJIflONIDJE,
Dotata. Testa increment! lineis concentrice rugata, postice plicis
paucis raro notata et valde evanescentibus. Dentibus minimis
ut in M. salweniana. Nacrea csBrulescente, umbones versus
flavescente.
Long. 52, lat. 96, diam. 28 mm.
Mob. Near Mandalay.
Allied to P. salweniamis, but differing from that species in its
more elongate form and smoother sui'faee; _voung specimens
occasionally show traces of sculpture' on the posterior slope, but
this character disappears when adult.
Genus PARREYSIA.
Parrei/sia, Conrad, Proc. Acad. Nat. Sci. Philadelphia, vi, 1853,
p. 267; Simpson, Proc. Acad. Nat. Sci. Philadelphia, xxii, 1900,
p. 640.
TYPE, Unio midticlentakis, Philippi. Said to come from
Australia but probably an Indian shell.
Range. India; Burma; Indo-China; China.
Shell solid, inflated, oval to subrhomboid, with full, high, zigzag,
radially sculptured beaks, the sculpture often extending over the
disk ; epidermis smooth and bright, sometimes a little rayed, with
two irregular pseudocardinals in the left valve which are more or
less broken into ragged denticles or are strongly, vertically striate,
and two laterals, the lower the larger; right valve with one,
sometimes two pseudocardinals, the upper small, compressed, and
a few tubercles behind them, with two laterals, the upper the
larger; cavity of the beaks rather deep, not compressed ; dorsal
scars under the hinge, not visible; the two upper anterior muscle
sears very deep, confluent, the lower linear; nacre white to
salmon, iridescent behind.
Animal unknown.
Conrad's name appears to be a nomen nudum and Simpson,'s
description is therefore that given above.
Subgenus PAEEEYSIA {sensu stricto).
Parreysia, Conrad, 1853.
I'or type, range and characters see description of genus above.
290. Parreysia (Parreysia) corrugata (Miiller).
Parreysia (Parreysia) corrugata (Miiller) ; Simpson, Washington,
D.C., Smiths. Inst., Nat. Mus. Proc. xxii, 1900, p. 841.
Mya corrugata, Miiller, Verm. Terr, et Fluv. 1774, pt. 2, p. 214;
Beseh. Gea. Berl. iv, 1779, p. 66, pi. 3 b, figs. 7, 8; Qmelin, Syst.
Nat. 13th ed. 1788, p. 8221; Schroter, Flussconch. 1779,
p. 181, pi. 9, fig. 3; Wood, Gen. Conch, i, 1815, p. 108, pi. 24,
figs. 1-3; Dillwyn, Cat. i, 1817^ p. 52; Mawe, Linn. Conch.
1823, pi. 4, fig. 3; AVood, Ind. Test. 1825, p. 12, pi. % fig. 31 a;
1856, rev. ed. p. 10, pi. 2, fig. 31.