REVISION OF THE DEEP-WATER MOLLDSCA OF THE 

 ATLANTIC COAST OF NORTH AMERICA, WITH DE- 

 SCRIPTIONS OF NEW GENERA AND SPECIES. 



PART I. RIVAL VIA. 



By ADDISON E. VERRILL, 



Prof essor of Zoology in Yale rnirersity 

 arid 



KATHARINE J. BUSH, 



in Pcabody Museum of Tale I'nicersify. 



THIS article is not intended as a review of all the known species 

 found oft' our coasts. It is preliminary to a much more extensive 

 report, in which full details of the distribution of all the species col- 

 lected will be given, and for which the detailed tables have been pre- 

 pared, giving every station for each species, with its position, depth, 

 temperature, character of the bottom, etc. 



Many of the larger and more prominent species were described and 

 figured by the senior author several years ago in various papers pub- 

 lished in the Transactions of the Connecticut Academy and elsewhere. 

 Tlie smaller and more difficult species were put aside at that time, for 

 more careful study, and are now presented. 



The families that are most fully treated in this article are the Lediclae, 

 Cuspidaridpe, Diplodoutida-, and Pectiimhe. These include a very 

 large number of deep-sea species in every region, and their species are 

 often very difficult to distinguish without long and patient microscopic 

 study and direct comparison of large series of specimens from various 

 localities. 



The present article is intended to give some of the results of studies 

 of this kind, made during several years, of the large series of speci- 

 mens dredged by the United States Fish Commission off our coasts 

 from 1871 to 1887, together with those previously dredged by the senior 

 author in the same region. 



PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. XX No. 1139. 



775 



