EAST AMERICAN SCAPHOPOD MOLLUSKS. 



65 



it to be undoubtedly of the same group of D. jloridense, but not con- 

 specific. The Pourtales shell from the Gulf Stream off Bahia Honda, 

 doubtfully referred to by Watson in the CJiallfnger Report as D. 

 paucicostatum, is probably D. foridense. It is evidently a warm- 

 water species of the continental shelf zones of the Antilles. Watson's 

 specimen from off Culebra Island in 390 fathoms is only a fragment 

 and very difiicidt of determination.' Under such circumstances I 

 do not think it should be accepted as identical with a European 

 species of boreal station. 



The followiny: lots are in the museum collection: 



Subgenus GRAPTACME Pilsbry and Sharp, 1897. 

 1897. Griptacine Pilsbry and Sharp, Tryon's Man. of C'onc hology, vol. 17, p. 85. 

 The shell is sculptured with very close, fine, deeply engraved 

 longitudinal striae near the apex, all the balance of the shell being 

 smooth. The apical characters are variable. They constitute a 

 group of small to medium sized shells, generally living in moderate 

 depths. The extent of surface occupied by the sculpture is also quite 

 variable. The chief character of the subgenus is in the very fine 

 engraved lines of the posterior portion, as contrasted with the more 

 prominent ribbing so characteristic of other groups heretofore con- 

 sidered. The tips are never angled. The texture of the shell is 

 usually glassy, with a smooth shining- surface in the anterior portion, 

 and the section is always round. The following key to the western 

 Atlantic forms roughly characterizes the few species: 



KEY TO THE SPECIES OF THE SUBGENUS GRAPTACME. 



Apical aperture with slit plug _ calamus, page 72. 



.\pical aperture without slit plug. 



Api( al slit on convex side, deep and narrow. 



With more than 20 longitudinal engraved lines eboreum, page 66. 



With less than 20 longitudinal engraved lines circumcinctum, page 68. 



Api( al slit laterally pla-red. 



Large (25 to 34 by 3 to 4 mm. ) semintriolatum, page 69. 



Small (17 by 1.5 mm.) amaliense, page 71. 



Apical slit doubtfully placed. 



Vivid zigzag gray color bands sericatum, page 71. 



1 ChallengeT Report, p. 2. 



