THE NAUTILUS. 45 



177. — Cardiion piu)ndatum, Conrad. 



Shell small, su])-orbicular, beaks slightly elevated, surface dingy- 

 white, with twenty-six ribs radiating from the beaks, sei)arate(l 

 from each other by deep grooves ; on each rib is a series of equi- 

 distant arched scales or spines ; interior flesh colored or white, fur- 

 rowed to correspond with the exterior ribs. Length i, height 4-10, 

 breadth 3-10. This pretty little shell is found generally in the 

 stomachs of fishes. It inhabits from Long Island Sound to Labra- 

 dor. It is rare in Long Island Sound, a little more abundant in 

 Narragansett Bay and quite common in Buzzard's Bay and Vin- 

 yard Sound in four to twelve fathoms' water. Conrad found his 

 specimens in INIassachusetts Bay and described the species in Journ. 

 Acad. Nat. Sci. Phila., vi, 260, 1831. 



Genus Laevicardium, Swainson, 1840. 



The genus Cardium has radiating ribs on the exterior which 

 interlock at the margins. Laevicardium has a smooth surface, but 

 most of the species have interlocking margins. There are twenty- 

 one species of universal distribution, one of which inhabit R. I. 



178. — Laevicardium Mortonii, Con. 



Syns. 



Cardimn Mortonii, Con., DeKay, Stimp., Smith. 

 Liocardium Mortonii, Stimp., Dall, W. G. Binney. 

 Laevicardium Mortonii, Reeve, Tryon, Perkins. 



Shell thin, sub-globose ; beaks large, nearly central ; surface 

 smooth, glossy white, yellowish or fawn color ; interior bright yel- 

 low, excepting the margins which are white, and a dark purple 

 blotch on the posterior margin. Length one inch, height 9.10, 

 breadth 7.10. 



Described by T. A. Conrad at the same time with Cardium 

 pinnulatum. It ranges from Cape Cod to Florida and the north- 

 ern shores of the Gulf of Mexico. It is quite abundant in R. I. 

 at times, and at others very scarce, although young specimens may 

 be seen on our sandy shores at all times. The young shells usually 

 have zigzag blotches of dark brown on the exterior surface, Avhich 

 disappears as the shell approaches maturity. 



FAMILY VERTICORDID.E. 



Not represented in America. 



