96 AMERICAN MARINE CONCHOLOGY. 



Family DENTALID^E. 



Genus DENTALIUM, Linnaeus. 



Syst. Nat., edit. x. 785. 1758. 



The " tooth shells" are tubular, symmetrical, curved, open at 

 each end, attenuated posteriorly; surface smooth or longitudinally 

 striated ; aperture circular, not constricted. 



The animal is attached to its shell near the posterior anal ori- 

 fice ; head rudimentary, no tentacles or eyes ; oral orifice fringed ; 

 foot pointed, conical, with symmetrical side lobes, and an atten- 

 uated base, in which is a hollow communicating with the stomach. 

 Branchiae two, symmetrical, posterior to the heart ; blood red ! 

 Sexes united ? Tongue denticulate. 



These anomalous animals are animal feeders ; they live in all 

 seas, ranging from ten to one hundred fathoms. 



1. D. DENTALE, Linnaeus. Fig. 195. 



Syst. Nat., edit. xii. 1263. 1767. 

 Dentalium striatum, Montagu, Test. Brit., 435. 1803. 

 Dentalium attenuatum, Say, Journ. Philad. Acad., iv. 154, t. 8, f, 3. 1825. 

 Dentalium occidentale, Stimpson, Shells of New England, 28. 1851. 



Shell slender and tapering, shaped like an elephant's tusk ; the 

 tip cut off, leaving a very small opening. Surface rather glossy, 

 yellowish-white, marked with about twenty closely arranged une- 

 qual rib-like striae, running the whole length of the shell. 



Length 1 inch. 



New England. 



2. D. STRIOLATUM, Stimpson. Fig. 196. 



(Entalis.) Proc. Bost. Soc. Nat. Hist., iv. 114. 1851. 

 Dentalium entalis, Mighels (not Linn.). 

 Dentalium abyssorum, Sars. 1858. 



Shell large, slightly curved, rugose from the growth lines, but 

 destitute of longitudinal striations. White. 

 Length 2 inches. 



Maine. (Eur.) 



This species has been referred to the genus Entalis, which is 

 said to be distinguished from Dentalium by the presence of a 

 notch-like or narrow longitudinal fissure communicating with the 

 perforated apex. Upon examination of a large number of species 

 I find that, in some at least, this character is not even of specific 

 value. 



