858 PllOCEEDINGS (>r Till: X.inoX.lL lirSEUX. VOL.XXII. 



escutcheon deep, triangular; beak cavities shallow; anterior muscle 

 Bears elongated; posterior faint; iridescent behind.' 

 Animal unknown. 



LAMELLIDENS GUILLAINI Recluz. 



-.Inodontayitillaini RECLU/, Jl. deConch., I, 1850, p. 55; "Zeits. fur Mai., VII, 1851, 

 p. 140. *CROSSE, Jl.de Conch., XXXI, 1883, p. 222, pi. ix, Jig. 4. * P.-ETEL, 

 Conch. Sam., Ill, 1890, p. 180. 



Biava, northeast Africa, in the Somali country. 



Genus TRAPEZOIDEUS Simpson. 

 (Type, Uniofoliacea Gould.) 



Shell trapezoid, much compressed, with a low posterior ridge, and 

 but slightly raised though pointed beaks, which seem to be sculptured 

 with irregularly radial ridges arranged in two imperfect chevron-shaped 

 loops; surface concentrically sculptured, often having irregular radial 

 ridges on the posterior slope; epidermis yellowish-green or brownish, 

 with two or more green rays above the posterior ridge; teeth com- 

 pressed ; two pseudocardinals iu the left valve, one under the beak, the 

 other in front, often not well separated, and two laterals; right valve 

 with two pseudocardinals and one lateral ; pseudocardinals all irregu- 

 lar, olten pitted and peculiarly dentellate; laterals granular, showing 

 traces of vertical striation ; cavity of the beaks rather deep, compressed ; 

 muscle scars shallow, anterior scars separate; nacre soft, creamy, yel- 

 lowish in the beak cavities. 



Animal unknown. 



t TRAPEZOIDEUS FOLIACEUS Gould. 



" 1'iiio foliacea GOULD, Pr. Boat. Soc. N. Hist., I, 1843, p. 141; * Otia Conch., 1862, 

 p. 191. 



* I'nio foliaceus CATLOWand REEVE, Couch. Nom., 1845, p. 59. * H. and A. ADAMS, 



Gen. Rec. Moll., II, 1857, p. 492. * HANLEY and THEOBALD, Conch. Ind., 1876, 

 p. 19, pi. XLII, fig. 3.* ANDERSON, Yunnan Exp., 1877, p. 900, pi. LXXX, figs. 

 8-12. * P.ETEL, Conch. Sam., Ill, 1890, p. 153. 



* Hargaron ( Unio) folwceux LEA, Syn., 1852, p. 39; 1870, p. 62. 



*t I'nio pegiiensis ANTHONY, Am. Jl. Conch., I, 1865, p. 351, pi. xxv, fig. 2. 

 * SOWERBY, Conch. Icon., XVI, 1868, pi. xcv, fig. 519. *P^ETEL, Conch. Sam., 

 Ill, 1890, p. 162. 



*Hargaron ( Unio) peguensis LEA, Syn., 1870, p. 51. 



TRAPEZOIDEUS FOLIACEUS var. COMPTUS Deshayes and Jullien. 



" I'nio complus DESHAYKS and JULHEN, Nouv. Arch, de Mus., X, 1874, p. 126, pi. VI, 



tigs. 3, 4. 



r>i io fragile* NEVILL, Jl. As. Soc. Beng., XL VI, 1877, p. 39. *ANDERSON, Yunnan 

 Kxp., 1877, p. 400, pi. LXXX, tigs. 8-12. 



Burma; Cambodia. 



1 1 hardly know where to place this, as the description is lacking in several essen- 

 tial characters. It is probable that the beak sculpture is much like that of Lamelli- 

 deus iustead of being properly concentric, and it may be a subgenus of that group. 



