282 MANUAL OF THE MOLLUSCA. 
deep siphonal groove, which produces a slight projection on the 
margin. 
Animal with a broad head, destitute of tentacles; eyes sessile 
on prominent rounded lobes; gill? single. The siphonarize 
are found between tide-marks, ike limpets; Dr. Gray places 
them with the pulmonifera, between the auriculide and cyclos- 
tomidee. 
Distribution, 41 species. Cape, India, Philippines, Australia, 
New Zealand, Pacitic, Gallapagos, Peru, Cape Horn. (Cuming.) 
Fossil, 3 species. Miocene—. France. 
FamiIty XITVY.—DENTALIADA. Tooth-shells. 
DENTALIUM, L. 
Type, D. elephantinum. Pl. XI., Fig. 27. 
Shell tubular, symmetrical, curved, open at each end, 
attenuated posteriorly; surface smooth or longitudinally 
striated ; aperture circular, not constricted.* 
Animal attached to its shell near the posterior anal orifice ; 
head rudimentary, eyes 0, tentacles 0; oral orifice fringed ; 
foot pointed, conical, with symmetrical side-lobes, and an 
attenuated base, in which is a hollow communicating with the 
stomach. Branchize 2, symmetrical, posterior to the heart; 
blood red (Clarke); sexes united? Lingual ribbon wide, 
oyate; rachis 1-toothed; uncini single, flanked by single 
unarmed plates. 
The tooth-shells are animal-feeders, devouring foraminifera 
and minute bivalves; they are found on sand, or mud, in which 
they often bury themselves. The British species range from 10 
—100 fathoms. (Forbes.) 
Distribution, 50 species. West Indies, Norway, Britain, 
Mediterranean, India. 
Fossil, 125 species. Deyonian—. Europe, Chili. 
FAMILY X VY.—CHITONIDA. 
Curton, L. 
Htymology, chiton, a coat of mail. 
Examples, OC. squamosus, spinosus, fascicularis, fasciatus. Pl 
XI., Figs. 23—31. 
* D. gadus of Montagu is an anneilid, belonging to the genus ditrupa, 
