394 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



SOLENOCONCHA. 



Dentaliuni occidentale Stimi). 



Shells of Now Eugland, 1851 (based on D. dentale Gould, 1st ed., p. 155, fig, 



5, not of European authors). 

 DentaUum dentale Gould, Invert, of Mass., 2d ed., p. 230. 

 DentaUum ahyssorum M. Sars, 1858. 

 DentaUum striolatum Jeffreys (non Stimpson). 

 Antalis striolata G. O. Sars, Moll. Eeg. Arct. Norv.,p. 101, pi. 7, fig. 1; pi. 20, 



figs. 10 a, h ; pi. 1, figs. 1 a-c, dentition {non Stimpson sp.). 



This species is abundant on muddy bottoms, in 50 to 300 fatlioms, all 

 along the coast of l^ew England and IS^ova Scotia. 



Mr. Jeffreys, misled by a singular and unaccountable mistake, has 

 constantly applied to this sulcated species the name given by Stimj^soii 

 to our common, shallow- water, nearly smooth form. In this mistake G. 

 O. Sars and others have followed him. 



The question as to the specific distinctness of these two forms I do not 

 propose to discuss at this time, but it is equally desirable that the 

 respective names should be correctly ajiplied, whether we regard the 

 forms as varieties or species. Of D. striolatum^ I have dredged thou- 

 sands of specimens in shallow water in the Bay of Fundy, in the same 

 region where Stimpson's original specimens were taken, and amojig them 

 no specimens of "i>. occidentale^^ are to be found. In other localities, how- 

 ever, both species occur together. Both were taken this season on the 

 outer banks, off Newport. But D. occidentale was by far the most com- 

 mon, and was abundant in the deeper stations, where i>. striolatum did 

 not occur at all. 



Among the specimens taken by us there are many that are more 

 strongly ribbed and sulcated than usual, the ribs being more or less 

 angular and elevated. In some of these, which are slender and about 

 an inch long, the internal surfiice of the shell has grooves corresj^onding 

 to the external ribs, the shell being thin, but of uniform thickness, so that 

 the two surfaces are parallel. In others of the same size the bore of the 

 shell is smooth and round, the shell being thickened opposite the ribs. 

 I am not prepared, however, to say that this is anything more than a 

 varietal difference. 



The form of the posterior notch varies in all our species (or varieties) 

 from a shallow notch to a triangular cut, and even to a deep slit. 



Siphonodentalium vitreum Sars. 



G. O. Sars, op. cit.,p. 103, pi. 7, figs. 2 a-c; pi. i, figs. 2 «-/ (dentition). — Yer- 

 rill. Trans. Conn. Acad., v, pi. 42, fig. 19. 



A fine, large specimen, jjrobably belonging to this species, was 

 dredged by the party on the " Bache ", in 1873, in the Gulf of Maine 

 (station 12 B), in 60 fathoms, mud. 



The shell is smooth, round, very thin, transparent, and lustrous. It 

 is slightly curved and exi)ands gradually to the anterior end. The pos- 

 terior oj)ening is small and round, without lobes, but it probably has 



