NYMPHACEA. MOLLUSCA. LUCINA. 69 



semi-oval before the beaks ; the posterior slope sudden and nearly 

 straight, forming a blunted angle by its junction with the base ; 

 marginal fold well marked ; surface regularly and delicately mark- 

 ed by sharp lines of growth ; color white, or slightly tinged with 

 rose-color, and iridescent ; ligament short and prominent ; cardi- 

 nal teeth two in each valve, the posterior one of the left valve 

 rudimentary, the principal one in each valve grooved ; lateral 

 tooth on the longer side distinct ; that on the shorter side, just 

 behind the ligament, scarcely perceptible ; sinus of the palleal 

 impression nearly reaching the anterior palleal impression. Length 

 1^ inch, height /^ inch, breadth ^^^ inch. 



Found abundantly cast upon all our sandy beaches, and prob- 

 ably lives not far from low-water mark. 



It is a very pretty little species, its beauties becoming developed by 

 examination. There are two other species closely allied to it ; the T. 

 polita, which is a somewhat larger and stronger shell, its posterior 

 angle more prolonged and sharper, and its surface smooth, glossy, 

 porcelain-white ; also T. iris, of about the same size, solidity, and 

 color, but its surface is marked by oblique grooved lines v/hich at 

 once distinguish it. This is not found on our shores, nor am I cer- 

 tain that T. pollta has been. It is not likely to be confounded with 

 any other shell. 



Genus LUCInA, Brug. 



Shell rounded, beaks small ; two diverging cardinal teeth, one 

 of tchich is bifid, and usually two lateral teeth, one of them near the 

 cardinal teeth, in each valve ; there is sometimes a posterior angle, 

 but never a fold, as in TelUna ; palleal impression loithout a 

 sinus. 



Luci'NA ra'dula. 



Shell orbicular, compressed ; surface with numerous concentric, 

 laminated stricB ; lunule depressed, lanceolate ; lateral teeth wanting. 



State Coll., No. 213. Soc. Cab., No. 2330. ' 



TelUna radula, Montagu ; Test. Brit., 68, jiX. 2, f. 2. Pennant; Brit. Zool.,iv. 

 181. Rackett ; Lin. Trans., viii. 54. Wood ; Gen. Conch., 183, pi. 42, 

 f. 4,5. TvRTOjn; Brit. Biv ,116. Conch. Diet., 175. Chemn. ; Conch., \ii. 16, 



