On the Mollusca of Long Island. l^T 



My cabinet, and cabinet of Mr. Rowell. 



Bemarlcs.—Thh approaches nearest to P. ovata Say, from 

 which it differs, however, in many of its details. I am not 

 aware that any species of this Genus has heretofore been found 

 in this State. 



I take pleasure in dedicating this species to the Eev. Mr. 

 Kowell of San Francisco, an active collector, and enthusiastic 

 conchologist. 



XX.— On the Molltjsca of Peconic and Gardiner's Bays, 

 Long Island, New TorTc. 



Bt Sanderson Smith. 

 Eead Decemtier 5th, 1859. 



Peconic and Gakdinek's Bays, which together indent the 

 extremity of Long Island to the depth of more than twenty 

 miles, ofler especial advantages for the study of the Inverte- 

 brata of our Atlantic coast. Situated at the junction of the 

 Atlantic and Boreal Molluscan Provinces of Forbes, they have 

 a greater proportion of species common to both than any other 

 locality with which I am acquainted. Out of the 96 species, 

 excluding Tunicata, occurring in the bays, 62 or Q4:-Q per cent, 

 pass Cape Cod, and including five species found about Mon- 

 tauk Point, but not in the bays, the proportion for the east end of 

 Long Island becomes 67 out of 101, or 66-3 per cent. Stimpson 

 gives only 27 other species as found on both sides of the Cape, 

 making the entire number 94, of which 71-3 per cent, occur in 

 the bays and around Montauk Pt. 



Of the 96 species of the Bays, 1 is a Cephalopod, 45 Proso- 

 branchs, 1 Pulmonifer, 3 Tectibranchs, 1 Nudibranch, and 45 

 Lamellifers. Besides these, at least 18 or 19 species of Tunicata 

 exist, making the total number of Mollusca about 115. 



