LUCINA. 99 



terior muscular impression very narrow, and directed ol^liquely to 

 the centre of the valves. Length, one and one half inches ; height, 

 the same ; breadth, six tenths of an inch. A specimen dredged by 

 Dr. Stimpson in Boston Harbor has the diameter, one and seven 

 eighths of an inch ; breadth, seven eighths of an inch. 



This must be considered a rare shell, and an inhaliitant of deep 

 water. A few valves liave been picked up on our beaches after 

 severe storms. It is a common shell on the other side of the At- 

 lantic. In six fathoms sand. Point Shirley {Stimpson) ; on Phil- 

 lips's Beach after a storm, alive (Holder). 



Dr. Stimpson has very truly pointed out the distinction between 

 the L. radula of Montagu and our shell. The latter is larger, more 

 compressed, thinner, more muddy-colored, and the concentric lam- 

 ina are more elevated and more distant. 



Lucina dentata. 



Shell white, orbicular, lenticular, sculptured with grooves bent obliquely down- 

 wards at both sides ; lateral teeth obsolete ; margin dentated. 



Pectunculus parvus, List. Conch, t. 301, fig. 142. 



Tellina divaricata, Gmel. Syst. iv. 32-41. — Chemn. Conch, vi. 134, pi. 13, fig. 129. — 



DiLLWYN, Cixtal. i. 102. — TuRT. Conch. Diet. 178. 

 Lucina dentata, Wood, Gen. Conch. 195, pi. 46, fig. 7 ; Index Test. (Tellina) pi. 4, fiff. 88. 

 Lucina divaricata. Lam. An. sans Vert. 2d ed. vi. 226 ; An. du Mus. vii. 239. — Desii. 



Encyc. Me'th. Vers., iii. 376, pi. 28.5, fig. 4. — Blainv. M.nlacol. pi. 72, figs. 3, 3 a. — 



Gould, Inv. Mass. 1st cd. 70. — De Kay, Nat. Hist. New York, 214, pi. 26, fig. 273. 



— CiiENU, Man. de Conch, ii. 120, fig. 572. 

 Lucina strirjilla, Stimpsox, Shells of New England, 17. 



Shell white, thin, rounded, regularly convex, sulj-equipartitc ; 

 beaks elevated, inclined forwards, in front of which is a long 

 and narrow areola somewhat crested. Surface 

 glossy ; stages of growth strongly marked ; 

 deejdy sculptured with regularly dis])Osed, re- 

 mote, and nearly parallel lines, flexed at nearly / 

 right angles along the anterior third, so as to K 

 pass obliquely downwards towards both ends, 

 and forming teetli around the entire margin, 

 most prominent behind. Hinge margin nearly 

 straight. Teetli, one in the right valve, very 

 small, and two small, diverging ones in the left valve. Marginal 

 teeth wanting or rudimentary. Ligament almost entirely concealed. 

 Length, one inch ; breadth, three fifths of an inch ; height, nine 

 tenths of an inch. 



