LIOGARDIUM. 143 



Liocardium Mortoni. 



Shell small, thin, sub-globose, smooth, pale fawn-color, sometimes blotched 

 with dark brown; within striated, bright yellow, with a purplish blotch pos- 

 teriorly. 



Cardiiun Mortoni, Conrad, Journ. Acad. Nat. So. vi. 259, pi. 11, figs. .5, 6, 7 (1831); 



Sillim. Journ. xxiii. 346 (1833). — De Kay, Nat. Hist. New York, 207, pi. 23, fig. 251. 



— Stimpson, Shells of New England, 19. — Smith, Moll, of Long Island, 16, and 



in Aim. New York Lye. vii., and Sillim. Journ. xxvii. 283. 

 Liocardium Mortoni, Stimpson, Cheek Lists, 2. 



Shell small, thin, obliquely sub-ovate, sub-globose ; beaks large 

 and prominent, incurved, nearly central ; posterior part a little pro- 

 duced and directed ol)liquely downwards; sur- 

 face glossy, destitute of ribs or radiating lines, ^^^' ^^^' 

 with fine lines of growth, and an occasional 

 darker zone ; color very pale yellowish, cov- 

 ered with a very thin, darker epidermis, 

 thicker and more wrinkled behind ; in young 

 specimens are l)lotches or zigzag lines of dark 

 fawn-color ; teeth well devcloijcd ; inside with 



' , ... -L- Mortoni. 



very faint and minute radiating lines ; mar- 

 gin white, the remainder bright yellow ; there is always a dark pur- 

 plish blotch along the posterior margin, and it is sometimes mot- 

 tled with bands and stains of reddish-brown on other parts of the 

 interior; muscular impressions superficial. Length of largest spe- 

 cimens one inch ; height, nine tenths of an inch ; breadth, seven 

 tenths of an inch. 



The animal is white, and has short, conical siphons, each marked 

 with a circle of brown spots, and fringed with numerous cirri 

 which extend far beyond the shell ( S. Smith'). 



Found plentifully about Nantucket, Martha's Vineyard, and Rhode 

 Island, south of which I cannot learn that it has been found. Ex- 

 tremely abundant at the mouths of creeks and on shallow flats, from 

 low-water mark to two fathoms, Peconic and Gardiner's Bay, Long- 

 Island (^ Smith} ; Dartmouth Lakes, Halifax (^Willis). 



This shell is very closely allied to the C. IcBvigatum of the West 

 Lidies, and has no other well-marked distinction than the purple 

 blotch on the posterior margin within, which, so far as I have ob- 

 served, is never wanting in our species, and never present in the 

 West India shell. In the angular markings of the young shells 

 they are similar, and also in their form and color ; but the exterior 



