ASTAPvTE. 



127 



A. crebrirostatn. 



but sometimes fading out on the ventral half, with every interme- 

 diate degree, and rarely extending to the posterior end exeept about 

 the beaks, wliei-e tlu^y are very erowded and 

 complete ; epidermis rusty-brown. Interior 

 milk-white ; hinge moderately developed ; edge 

 in adults very finely crenate. Length, one and 

 one tenth inches ; breadth, one inch. 



Found at Eastport, and at Anticosti Isl- 

 and (^Stimpsoii)', Dauphin Harbor, Labrador 

 (Packard) : young specimens in abundance, 

 Halifax {Wi//is). 



In the way of form there is nothing to dis- 

 tinguish this species from others. It under- 

 goes all the variations of altitude and elongation, of acumination 

 and truncation, inflation and compression, that are observed in 

 others. Its leading character seems to l)e its very numerous waves, 

 always conspicuous about the beaks, but often disappearing in the 

 later stages of growth. A series of the young may be selected which 

 would satisfy any one as to specific value ; while intermediate si)eci- 

 mens would so connect it with A. sulcata, elUptica, Banksii, and 

 compressa as to be a complete puzzle. A large compressed form, 

 to which I notice that Dr. Stimpson has attaclicd a label in his 

 collection with the name A. lens, I think would fall under this spe- 

 cies, though it merges almost as well into A. sulcata. The speci- 

 mens originally described were found in very deep water, only 

 single valves, and in an eroded, chalky, half-fossilized condition. 

 I have a single valve from Professor Morch, said to have come 

 from Iceland, which corresponds more with the lenticular form 

 last mentioned than the more rounded and tumid sent by Mr. 

 McAndrew. If it is to be regarded as a species it is evidently a 

 Cisatlantic shell, only found astray on the other side. 



A. pulchclla, Jonas, of which I have seen an authentic specimen 

 from Spitzbergen, appears to be an elongated, closely striated form, 

 such as I have seen mingled with young specimens of the shell under 

 consideration. 



Astarte Portlandica. 



Shell small, ovate-triangvilar, beaks elevated at the posterior third, ends rounded, 

 margins simple, surface nearly smooth, interior livid. 



Astarte Portlandica, Mighels, Bost. Juurn. Nat. Hist. iv. 320, 345, pi. 1 6, fig. 2. — Stimp- 

 son, Shells of New England, 18. 



