INSTITUTE OF SCIKNCE, PHILADELPHIA. 439 



some unmentioned Eocene locality, is perhaps a fragment of D. microstria 

 Heilprin. D. turritum Lea is an immature Cadiihcs. D. siibcompressum Meyer 

 seems to be a valid species of the Jackson and Vicksburg Eocene, identifiable 

 by its smooth surface and oval section. 



D. incisissimiim Meyer and Aldrich, from Wahtubbee, is described from 

 a small fragment as cylindrical, smooth, polished, and with a long dorsal slit 

 behind. 



In the Miocene the species are more numerous. A large number have 

 been described by Gabb and Guppy, from the Antillean Older Miocene, most 

 of which are still unfigured. 



Dentaliutn attenuatum Say. 



D. alteniiatum Say, Journ, Acad. Nat. Sci. Phila. iv. p. 154, pi. viii. fig. 3, 1824; Tuomey 



and Holmes, Pleioc. Fos. S. Car., p. 105, pi. 25, f. i. 

 D. dentale Conrad, Fos. Tert. Form., p. 78, pi. 44, fig. 9 ; not of Linne. 

 L). duodecenaria Conr., Proc. Acad. Nat. Sci. 1862, p. 570, 1863. 



Chesapeake Miocene of Maryland, Virginia, North Carolina, South Caro- 

 lina, and the Ecphora bed at Alum Bluff, Chattahoochee River, Florida ; Plio- 

 cene of Costa Rica, Gabb. 



This widespread and well-known species is closely allied to D. denialis L., 

 of Southern Europe, from which, however, it seems to me distinct. It is some- 

 what doubtful if the Costa Rica shell is identical. 



Dentalium carolinense Conrad. 

 D. carolinense Conr., Proc. Acad. Nat. Sci. Phila. 1862. pp. 288, 570, 1863. 



Chesapeake Miocene of North Carolina, Conrad ; of James River, Va., 

 Burns; of the upper bed at Alum Bluff, Chattahoochee River, Florida, Burns; 

 and of the artesian well at Lake Worth, S. E. Florida. 



This species, which has not been figured, is readily distinguished from D. 

 attennatHmhy \1s larger size, fewer (8 to ii) ribs, and much broader interspaces, 

 and generally coarse and rude appearance. It reaches a length of 40 to 45 

 mm., a maximum diameter of 5 mm., and has a very thick, earthy and little- 

 curved shell. 



Dentalium Danai Meyer '> 

 D. Danai Meyer, Bull. Ala. Geol. Survey, p. 64, pi. 3, f. 2, 1886. 



Eocene of the Jacksonian, Ala., Meyer ; Older Miocene of the lower bed 

 at Alum Bluff, Florida, Burns ; Chesapeake Miocene of Plum Point, Md., 

 Darlington C. H., S. Car., and Duplin Co., N. Car., Burns. 



It is impossible to distinguish between the fragments received as author's 

 specimens of D. Danai and a smooth species not uncommon in the Miocene. 

 The characters of the type-specimen of D. Datiai are duplex. First the shell 



