DENTALIID^. 115 



SiPHONODENTALlUM, M. Sai'S, 1859. 



Dislr. — S. vitreum^ Sars (ciii, 100). N. Europe. 



Shell slightly attenuated, apex incised-lobate. Terminal pedal 

 disk concave in the middle, no median tentacles. 



The posterior orifice exhibits two slight notches on each side, 

 and the foot is ordinarily A'ermiform and pointed, expanding 

 only in a flower-like shape when the animal uses it as a fulcrum. 



PULSELLUM, Stoliczka, 1868. (Siphonoentalis, G. 0. Sars.) Shell 

 tubular, thin, smooth or longitudinallj^ ribbed, gradually tapering 

 towards the posterior end, which is truncate, with the margin 

 entire. The animals closel}^ resemble those of Siphodent. vitreum, 

 only showing slight difi'erences in the ciliated fringe of the foot- 

 disk, but the shells are readily distinguished from it by the 

 entire margin of the posterior end ; this distinction also applies 

 as regards Dentalium, but the separation from Antale is more 

 difficult, being apparently restricted to the more truncated shape 

 of the posterior end in the present genus, and to a more hyaline 

 structure of the shell. S. Lofoten .ds^ Sars. 



Cadulus, Philippi. 



Syn. — Gadilia, Gray, 184*1. Helonyx, Stimpson, 1865. Gadus, 

 Deshayes. 



Distr. — 2 sp. Norway, Hong Kong. Fossil, numerous ; Paljieo- 

 zoic, Jurassic, Cretaceous, etc. G. subfusiformis, Sars (cii, 99). 



Shell short, more or less inflated in the middle, apical orifice 

 entire, circular, with annular, suboblique internal plica remote 

 from the apex. Terminal pedal disk concave in the middle, 

 marginal tentacles slightl3^ elongated, median tentacles none ? 



Cadulus diflers from Siphonodentalium by the shell being 

 quite smooth, transparent and lustrous, tumid in the middle or 

 anterior portion, and its mouth encircled hj a narrow rim. 



Dischides, Jeflfreys (186t), 1883. 



Distr. — D. biftssus, Wood. Europe. 



Terminal slits bilateral. Animal whitish, gelatinous ; mantle 

 rather thick, forming a collar around the front opening of the 

 shell ; captacula issuing from within the mantle, numerous, 

 capable of so great an extension as to exceed the shell in length ; 

 stalks very slender ; terminal bulbs oval ; foot cylindrical and 

 narrow, protruded from the middle of the mouth as from a 

 sheath ; it is occasionally thrust out in a darting manner and 

 suddenly withdrawn, and so swiftly that the point of the foot 

 could not be observed ; the foot is usually curved towards the 

 point ; anal tube protruded beyond the narrower end of the 

 shell — it consists of an outer and inner part, the latter being- 

 folded to suit the slit on each side ; gills rather short, of a 

 brownish color. — Jeffreys. 



