176 



The chief differences appear to be, that the present species has 

 more general convexity and the spire itself is slightly convex : 

 beneath, the breadth is less considerable between the outer mar- 

 gin and the edge of the mouth, and the revolutions of the spire 

 within are much more obvious. PI. 25, upper and lower figures. 



SiGARETUS MACULATUS. — Specific character. Shell with two 

 maculated bands. 



Desc. Shell oval, depressed, with very numerous, transverse, 

 hardly undulated, sub equidistant, impressed lines, and longitudinal 

 wrinkles ; the transverse lines are obsolete beneath ; two bands of 

 pale rufous spots, and a rufous band near the suture : spire hardly 

 prominent, slightly convex ; volutions about three ; suture a simple 

 impressed line : aperture very large. 



Ohs. Although very much depressed, this pretty species is more 

 convex than the preceding, and the spire when viewed from the 

 side is more distinct ; the strise also are more close set. It differs 

 from all the species in having colored spotted bands, and within it 

 has a slight pearly appearance. This species is found on the 

 southern coast and is rare. PI. 25, middle figures. 



Venus. — Shell equivalved, inequilateral, regular, closed, trans- 

 verse or suborbicular ; cardinal teeth three on each valve, approxi- 

 mate, anterior and posterior ones diverging from the summit; liga- 

 ment exterior; muscular impressions two, not elongated, remote, 

 connected by the submarginal impression, which is deeply sinuous 

 before. 



Ohs. In this extensive genus are included some of the most 

 beautiful of bivalve shells. Linne referred to it species of the fol- 

 lowing genera : Petricola, Yenerupis, Sanguinolaria, Corbis, 

 Lucvna, Donax, Astarte, Oyrenay Cyprina, 3Ie</ades7na, Cytherea, 

 Venus and Venericardia. Although those species have been 

 since eliminated and more naturally distributed, yet in consequence 

 of the great accessions from the zeal of modern obsei-vers, and 

 owing to the considerable variation, both in sculpture and coloring, 

 that many of them undergo, great difficulty and uncertainty often 

 meet the conchologist in his endeavors to ascertain species, and 

 more than usual caution is requisite in detemining any one to be 

 new. 



In general form and exterior appearance these shells are undis- 

 tinguishable from Cytherea, but the hinge of the latter has the 



