1897.] NATURAL SCIENCES OF PHILADELPHIA. 465 



SCAPHOPODA OF THE SAN DOMINGO TERTIARY. 

 BY H. A. PILSBRY AND BENJ. SHARP, M. D. 



This account of the Scaphopods of the San Domingo tertiary 

 strata variously denominated Miocene or Oligocene, is an outcome 

 of investigations undertaken by the writers in the course of work 

 upon a monograph of the Scaphopoda published in the " Manual of 

 Conchology." It is based upon collections made by "VV. M. Gabb, 

 and briefly described in the Transactions of the American Philoso- 

 phical Society. 



Owing probably to Gabb's illness when he prepared the palae- 

 ontological part of the " Geology of San Domingo," and to his death 

 before its publication, the study of his material seems to have been 

 incomplete. Our examination of the material shows that of six 

 species described or recorded by him from the beds in question, 

 Dentalium rudis is the tube of a Serpuloid worm ; D. ponderosum is, 

 as Guppy has already claimed, a form of D. dissimile of the Jamai- 

 can Oligocene ; D. affine bears a preoccupied name, and Gadus dom- 

 inguensis is not that species, but a new one allied to the form called 

 Ditrupa dentalina by Mr. Guppy. Among the specimens of the 

 species discriminated by Gabb, and in several trays of undetermined 

 specimens, we have been able to distinguish ten new and well-charac- 

 terized forms, besides several which are probably distinct species, 

 but being represented by young or very fragmentary individuals 

 have been ignored in the following account. 1 



As to the age of the deposit in San Domingo furnishing these 

 remains, and that of the same horizon at Bowden, Jamaica, there is 

 diversity of opinion. Gabb and some others have considered it 

 Miocene; and in view of the considerable number of species still 

 existing in the Gulf of Mexico, and the close relationship of many 

 of the extinct forms with living species, this estimate is not without 

 support. Conrad, however, in 1852 2 and again in 1866 3 expressed 



1 Among these, fragments of a species probably referable to our subgenus 

 Episiplion may be mentioned. This group is represented in the German 

 Oligocene by Dentalium otloi Sharp & Pils. 



2 Proc. Acad. Nat. Sci. Phila., 1852. p. 198. 



3 Check List of the Invertebrate Fossils of North America, Eocene and 

 Oligocene. Smiths. Misc. Coll., VII, no. 200, p. 37. 



