229 



nitida, Poll, but tlie beaks are rather more anterior. The anterior 

 side is a little more obtuse than that of T. jndcheUa, Lam., and a 

 little more curved to the left nearer the tip. It evidently resem- 

 bles T. depressa, Gmelin, but I cannot perceive any lateral tooth. 

 PI. 05, fig. 3. 



Tellina tenuis, Da Costa. — Specific character. Shell oval- 

 triangular, irregularly striate concentrically; each valve with two 

 teeth, and one of them with lateral teeth. 



Tellina tenuis, Da Costa, Brit. Conch., p. 210. Chem. 6, p 

 124, tah. 12, fig. 117. Donavan, t. tab. 19, three lower figures. 

 Penn. Brit. Zool. 4. p. 180, tah. bl,fig. 2. Mont. Test. Brit., p. 

 59. Turton, Brit. Fauna, p. 150. Wood, Conch, p. 155, to6. 44,. 

 figs. 3 and 4. Conch. Diet., p. 169. Conch. Ins. Brit., p. 107. 

 T. levis. List. Conch., t. 405, Jig. 251. 



Obs. There may frequently be observed some very minute and 

 tine longitudinal white lines, from which circumstance it has been 

 often mistaken for T. striata ; but the lateral teeth will at all 

 times distinguish it, there being two small lateral teeth in one of 

 the valves only. We believe that the T. balaustina and T.planata 

 of Linnaeus are among the numerous varieties of this species. — 

 (Turton.) 



I have copied the above from Turton's '' Bivalves of the British 

 Islands," believing our shell to be the tenuis of authors. Mr. Say, 

 unfortunately, has left no description of this species, which was 

 sent to him by Professor Bavenel of Charleston, who found it on 

 the shore of Sullivan's Island.— Ed.* PI. 64, fig. 3. 



Arca zebra, Swain. — Specific character. Margins angulated ; 

 valves marked with simple uniform and regular grooves, radiating 

 from the umbones ; shell transversely and obliquely striped with 

 brown. 



Arca zebra, Swainson. Zool. Illus., No. 26, p?. 118. 

 Obs. Inhabits the coast of the peninsular of Florida. 

 Mr. Swainson has separated this species from the Arca no^e of 

 authors, and refers it to his subgenus Byssoarca. He observes : 

 •'• The animals of these shells afiix themselves to other bodies by a 

 particular muscle, which is protruded through the gaping part of 

 the valves ; they also adhere, when young, by the byssiform epi- 



*[T. A. Conrad.] 



