250 NEW UNIONIDiE, MELANIDiE, ETC., 



for the folds and corrugations. The beaks of Homsensis are higher and their folds are 

 very different. The anterior part of the shell is also thicker. This is among the 

 many Unioniflce which Mr. Wheatle3' has been able to procure from Western Asia 

 tlirouo'h his friend the Rev. Mr. Beadle. 



"O' 



Unio Orphaensis. pi. 29, fig. 64. 



Testa lajvi, oblonga, insequilaterali, antice rotundata, postice obtuse subbiangulata ; valvulis crassius- 

 eulis, antice crassioribus ; uatibus subpromiueutibus, ad apices crebre et minute undulatis ; epi- 

 dermide olivacea, virido-radiata ; dentibus cardinalibus parvis, compressis, crenulatis, in utroque 

 valvulo duplicibus ; lateralibus longis subrectisque ; margarita vel alba vol aurea et valde 

 iridescente. 



Shell smooth, oblong, inequilateral, rounded before, obtusely biangular behind; 

 valves somewhat thick, thicker before; beaks somewhat prominent, closely and 

 minutely undulate at the tips ; epidermis olivaceous, with green rays ; cardinal teeth 

 small, compressed, crenulated and double in both valves; lateral teeth long and nearly 

 straight; nacre white or golden and very iridescent, 

 Proc. Acad. Nat. Sci. 1864, p. 285. 



Hah. — Tigris River, near Mardin, Pashalic of Orpha, Asiatic Turkey, C. M. 

 Wheatley. 



My cabinet and cabinet of Mr. Wheatley. 

 Diam. 1, Length 1-4, Breadth 2-7 inches. 



■ Shell smooth, oblong, ftiequilateral, rounded before, obtusely biangular behind ; sub- 

 stance of the shell somewhat thick, thicker before ; beaks somewhat prominent, closely 

 and minutely undulate at the tips; ligament large and deep brown; epidermis oliva- 

 ceous, with green rays on the posterior part and with distant, well defined marks of 

 growth ; umbonial slope rounded ; posterior slope narrow-elliptical ; cardinal teeth 

 small, compressed, crenulate, corrugate and double in both valves; latei-al teeth long, 

 lamellar and nearly straight ; anterior cicatrices distinct, rather large and well 

 impressed ; posterior cicatrices confluent and slightly impressed ; dorsal cicatrices 

 placed above the centre of the cavity of the beaks; cavity of the shell rather deep ; 

 cavity of the beaks rather deep and angular ; nacre white or golden and very iri- 

 descent. 



Remarhs. — Quite a number of sj^ecimens of different ages were kindly sent to me 

 by Mr. Wheatley for my inspection. In outline it is very near to some varieties of 

 complanatus, but it is more inflated and differs in the teeth. None of the specimens 

 were purplish, nor will it be found, I presume, to possess that color. Generally the 

 nacre is golden, but sometimes white. Some of the specimens have fine green rays 

 on the posterior half The full grown individuals have four or five broad marks of 

 growth. The first growth, forming the beautifully undulate tips, are in all the speci- 



