196 SUPPLEMENT. 



corresponding lines of growth slope backwards instead of 

 being circular, and the base or margin of the posterior orifice 

 is jagged, with two slight notches on each side ; the fry has 

 no bulbous point as in Dentalium. In some specimens the 

 periodical accretions of growth make them appear jointed. 



A specimen of S. vitreum was dredged by Carpenter and 

 Thomson in 550 f. off the Faroe Isles ; Sars and M'Andrew 

 have recorded it from much less depths on the coast of Nor- 

 way. S. affine of Sars appears to be the young of this species. 

 F. Norway (Sars and others) !; Vienna basin (Homes) ! 



Genus II. CA'DTTLTTS*, Philippi. 



BODY resembling that of SipTionodentalium. 



SHELL awl-shaped, tumid in the middle, and narrower at 

 each end, solid for its size, vitreous, and never exhibiting any 

 sculpture : mouth obliquely truncated and thickened : base 

 notched. 



Gadila, Gray, and Helonyx, Stimpson. Rang referred to 

 his genus Cresis the genera Vagindla of Daudin and Gadus 

 of Montagu ; but the last named author never proposed any 

 such genus. The type of the present genus is Dentalium gadus 

 of Montagu. My friend the Rev. M. J. Berkeley formerly 

 considered it an Annelid and belonging to his genus Di- 

 trupa (more properly Ditrypa) ; he is now satisfied that this 

 was a mistake. Species of Cadulus are numerous, both recent 

 and fossil. "We have only 



CADTJLTJS suBFu'siroRMisf, Sars. (Siphonodentalium sub- 

 fusiforme, Sars, Mai. Jagtt. p. 21, t. vi. f. 36-44.) 



BODY clear white : mantle irregularly fringed at its edges : 

 captacula thread-like, unequal in length, and very extensile, 

 annulated in a state of contraction ; each has an oval bulb at 

 the extremity : foot when at rest tubular, and projecting a 

 little beyond the mouth of the shell, when protruded nearly 

 as long as the shell itself, retractile like the tentacles of a 

 snail or slug ; its motion or action is spasmodic and extremely 

 rapid, as well in extension as in withdrawal ; disk resembling 

 a daisy, with the encircling lobes or digitations regular but 

 short ; this is sometimes concave, and at other times convex ; 

 its spike or tentacle is central : arms cylindrical, short : ovary 



* A. little cask. t Somewhat spindle-shaped. 



