22 NEW UNIONIDiE, MELANIDiE, ETC. 



Unio squalidus. pi. 7, fig. 20. 



Testa tevi, suboblonga, subinflata, valde inaBquilaterali. postice subbiangulata, antice rotundata ; valvulis 

 subcrassis, antice parum crassioribus ; natibus subprominentibus ; epidermide furva, squalida, imbri- 

 cata, eradiata; dentibus cardinalibus parvulis, striatis, in utroque valvulo duplicibus; lateralibus 

 sublongis, lamellatis subrectisque ; margarita cseruleo-alba vel purpurea et iridescente. 



Shell smooth, somewhat oblong, somewhat inflated, very inequilateral, subbiangular 

 behind and rounded before; valves somewhat thick, somewhat thicker before; beaks 

 somewhat prominent; epidermis dusky, squalid, imbricate, without rays; cardinal 

 teeth small, striate, double in both valves ; lateral teeth rather long, lamellar and 

 nearly straight ; nacre bluish white or purple and iridescent. 

 Proc. Acad. Nat. Sci., 1863, p. 192. 



Uah. — Neuse River, near Raleigh ; Roanoke, near Weldon, and Deep River, North 

 Carolina, E. Emmons, M. D. 



My cabinet and cabinet of Dr. Emmons. 

 Diam. -7, Length I'l, Breadth 2 inches. 



Shell smooth, somewhat oblong, rather inflated, very inequilateral, subbiangular 

 behind, rounded before ; substance of the shell somewhat thick, slightly thicker be- 

 fore; beaks somewhat prominent; ligament rather short and dark brown; epidermis 

 dusky, squalid, imbricate, without rays and with rather distant marks of growth ; 

 umbonial slope raised and obtusely angular ; posterior slope rather broad and some- 

 what carinate; cardinal teeth small, striate and double in both valves; lateral teeth 

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

 deeply impressed ; posterior cicatrices confluent, rather large and slightly impressed ; 

 dorsal cicatrices placed above the centre of the cavity of the beaks ; cavity of the 

 shell rather shallow and wide ; cavity of the beaks very shallow and rounded ; nacre 

 bluish white or purple and iridescent. 



Remarlcs. — This unattractive species was sent to me by Dr. Emmons from three 

 habitats in North Carolina. It has that rough, squamose epidermis which is generally 

 found in the group of which obesus, (nobis,) may be considered the type. It has the 

 same color of epidermis and the same dark squamose appearance, particularly on the 

 posterior slope. The beaks of ten specimens before me are all eroded, so that the 

 character of the tips cannot be observed. The undulations may have the same con- 

 volute character which that group possesses. In several specimens there is a dispo- 

 sition to tripartition of the cardinal tooth in the left valve. 



In outline this species is nearer to Bldndingianus, (nobis,) than to obesus, but it is 

 more transverse and less raised in the carina. 



