t^^l

PSBUDODoa-. 153
Long. 59, lat. 140, diam. 32 mm.
Hah. Salwen River, Burma; Tenasserim Eiver {Ind. Mus.
Coll).
288. Pseudodon (Pseudodon) nicobaricus {March).
Pseudodon (Pseudodon) nicobaricus (Morch); Simpson, Wasliington,
D.O., Smitks. Inst., Nat. Mus. Proc. xxii, 1900, p. 838.
Alasmodontn (subg. ?) nicobarica, 0. Fabricius; Morch, J. Conchyliol.,
Paris, XX, IBT-?^, 327.
Original description :—Testa irregulariter ovalis, convexiuscula ;
stT'iij ancrementi irregulares ; dimidium testse marginem versus
olivaceum, fasciis obscurioribus, radiis numerosioribus, obsoletis,
obscure viridibiis. Intus argeutea, postice iridescens. Umbones
plani, erosi, antice siti; marge dorsalis parum arcuatus, (margo)
anticus rotundatus, angustior, (margo) ventralis antice et postice
sat arcuatus, medio leviter inilexus, (margo) post, angustus leviter
reflexus. Dentes cardinis fere omnino evanescentes, dens lat.
post, linearis obsoletissimus.
Anodonta zollingeri, Mousson (Java, p. 28, t. 18, fig. 1), affinis,
sed species Pabricii differt: niargine ventrali arcuato, postice
subito ascendente, nee non margine dorsalis declivi, baud arcuato.
Hah. Nicobar Islands (0. Fabricius).
The species was described from a single specimen without figure
or dimensions being given, it does not seem to have come to light
again at any time.
Section BINEURUS.
Bineurus, Simpson, Washington, D.C., Smiths. Inst., Nat. Mus.
Proc. xxii, 1900, p. 839.
TrPE, Monocondyloea mouhoti, Lea, from Cambodia and Siam.
Mange. Cambodia; Siam ; Perak ; Burma.
Original description :—Shell elongate rhomboid, thin, rounded in
front, widely and feebly biangulate behind, having two or more
raised radiating lines on the posterior slope, which is somewhat
obliquely wrinkled ; beaks low; surface finely, irregularly, concentrically
grooved ; epidermis olive; teeth smooth, compressed;
nacre bluish.
Animal unknown.
289. Pseudodon (Bineuvus) ava {Theobald).
Pseudodon {Bineurus) ava (Theobald); Simpson, Washington,
D.C., Smiths. Inst., Nat. Mus. Proc. xxii, 1900, p. 839.
Monocondyl(ea ava, Tlieobald, J. A. S. B. xlii, 1873, pt. 2, p. 209,
pi. 17, fig. 15.
Original description :—Testa oblonga, solidiuscula, antice rotundata,
postice curvatim truncata. Margine ventrali recto ; ligamentali
convexo. Umbonibus decorticatis. Epidermide picea in
junioribus luteo-flavescente lineis tenuibus obscure radiatim