198 DENTALIID.E. 



tained specimens ; and I have likewise one which Dr. 

 Leach sent to Mr. Dillwyn, under the name of D. octo- 

 hedra, as found in Kent. 



D. eburneum, afterwards D. album of Turton (D. vari- 

 abile, Deshayes), is another un-English or spurious 

 species; its native country is said to be the East Indies. 



D. semistriatum of Turton must be, provisionally at 

 least, placed in the same category, although specimens 

 were taken by Mr. Humphreys from the stomach of a 

 red gurnard at Cork. I believe Turton's specimens 

 came from the same quarter, notwithstanding that 

 Dublin Bay is the locality given by him. It may be 

 the D. semipolitum of Broderip and Sowerby, or D. 

 semistriolatum of Guilding : if the former, the habitat is 

 unknown ; if the latter, it is West-Indian. 



D. clausum of Turton is certainly not a Dentalium, 

 nor even a shell ; it seems to be the lower part of the 

 quill of a sea-bird's wing feather. 



The cases of British species of Ditrupa (a genus of 

 testaceous Annelids) may easily be distinguished from 

 the shells of any species of Dentalium by their being 

 constricted near the front, and never having the tubular 

 appendage at the smaller end. They are thicker, and 

 of a crystalline structure. Such are Ditrupa arietina, 

 Muller (Dentalium subulatum, Deshayes), and Ditrupa 

 j Montagu (Dentalium coarctatum, Desh.) . 



