58 NEW UNIONID^, MELANIDiE, ETC., 



double in the right and trehle in the left valve ; anterior cicatrices distinct, rather large 

 and very deeply impressed ; posterior cicatrices confluent, large and well impressed; 

 dorsal cicatrices placed on the upper part of the cavity of the beaks ; cavity of the 

 shell wide and somewhat deep ; cavity of the beaks deep and obtusely angular ; 

 nacre pale salmon color, rich, satin-like and very iridescent. 



Remarlcs. — A single specimen of this species has been a long time in my possession. 

 It was brought by Dr. Burrough from India, among the many fine and rare shells he 

 so frequently procured during his voyages and his residence in India. Recently I 

 procured two specimens from a dealer, which are slightly thicker than the other. I 

 had always considered the specimens brought by Dr. Burrough as a large variety of 

 corrugatus, Retz., although there Avere but few corrugations on them. My new 

 acquisitions satisfy me that the species is certainly distinct. The three specimens 

 above mentioned are much larger and thicker, and weigh three times as much ; they 

 are sulcate, which corrugatus is not, and they are also of a broader oval ; and wliat 

 separates them conclusively from corrugatus, and all other species with which I am 

 acquainted, except one, the trifidus (nobis) from Buenos Ayres, is the tripartite 

 lateral tooth. In trifidus the treble tooth is in the right valve, while in tripartitus it 

 is in the left valve. The upper division of the cardinal teeth is compressed, while 

 the lower is deeply and beautifully corrugate. In all the valves before me there is 

 an indistinct ventral cicatrix, and the curve of the basal margin is slightly protruded. 

 The nacre is among the richest I have ever s.een. The color of the epidermis of the 

 specimen from Dr. Burrough is brownish above and yellowish green below. On the 

 other two bright straw yellow prevails, being greenish above. The habitat of Dr. 

 Burrough is certainly Jillingee River, but those specimens bought from a dealer, 

 while evidently from India, may not be from that river. 



Unio delicatus. pi. 19, fig. 56. 



Testa Isevi, elliptica, subinflata, inaequilaterali ; valvulis subtenuibus ; natibus prominulis, ad apices 

 undulatis et granulatis; epidermide straminea, cradiata ; dentibus cardinalibus parvis, compressis, 

 crenulatis. in utroque valvule duplicibus ; lateralibus sublongis, lamellatis rectisque ; margarita 

 albida et iridescente. 



Shell smooth, elliptical, somewhat inflated, inequilateral ; valves rather thin ; 

 beaks a little prominent, undulate and granulate at the tips ; epidermis straw- 

 color, without rays ; cardinal teeth small, compressed, crenulate and double in both 

 valves ; lateral teeth rather long, lamellar and straight ; nacre whitish and 

 iridescent. 



Proc. Acad. Nat. Sci., 1863, p. 189. 



iSi6.— River Orontes, Syria, C. M. Wheatley. 



Cabinet of Mr. Wheatley. 

 Diam. -42, ' Length -60, Breadth 1-01 inches. 



