some neiv and peculiar Mollusca. 157 



species of Helix : base notched on each side, as in G. suhfusi- 

 formis. L. 0-2. B. 0-075. 



Station 12, 1450 fms. : one specimen is abnormally arched. 

 ^Porcupine ' Expedition, 1869, Channel slope, 557 fms.: 1870, 

 Bay of Biscay, 292-1095 fms. ' Josephine ' Expedition, 110, 

 -550 fms. Fossil at Messina (Seguenza). 



This is much larger and more gibbous than G. suhfusiformis^ 

 and, like that species, it varies in shape and size. It has the 

 character on which Monterosato lays stress in generically sepa- 

 rating G. subfiisiformis from G. ovvlum^ viz. in the mouth 

 or anterior opening being more or less thickened inside by a 

 circular rib. 



Gadulus gracilis *, Jeffr. 



Shell more curved and cylindrical than G. suhfusiformis 

 (to which it is evidently allied) , not swollen in the middle, but 

 throughout nearly equal in breadth ; the mouth slopes more, 

 and has a slight circular rib or thickening within ; base 

 broader ; oblique marks of growth are conspicuous. L. 0"2. 

 B. 0-04. 



Station 13, 690 fms. ; a single specimen. 



Gadulus Oliviy .Scacchi. 



Dentalium Olim, Sc, Notiz. foss. Gravina (Ann. Civ. 1835), p. 56, tab. 2. 

 fig. 6, a, b. 



Station 12, 1450 fms. ; fragments only. ' Porcupine ' Ex- 

 pedition, 1869, West of Ireland, 1230 fms. ; south of the 

 EngHsh Channel, 862 fms. : 1870, Channel slope, 539 fms. 

 Sicilian Tertiaries (Scacchi, Tiberi, and others). 



Awl-shaped and variable in size. Probably Dentalium co- 

 arctatum of Lamarck, and certainly that of Deshayes and Phi- 

 lippi, is Dischides bijissus. 



G. gadus of Montagu resembles G. Olivi ; but it is not only 

 very much smaller, bat is proportionally shorter and less 

 slender, and the anterior end is more contracted. The locality 

 given by Montagu (" many parts of the British Channel "), 

 with the mariner's name " Hake's-tooth," is at least very 

 doubtful as regards this species ; and it is not unlikely that he 

 may have mistaken for the " Hake's-tooth " Ditrypa arietina 

 (a testaceous Annelid), which is frequently found adhering to 

 the grease or "arming" of the deep-sea lead in soundings. But 

 his description and figure evidently apply to a species of Ga- 

 dulus from the noted collection of old George Humphreys, the 



* Slender. 



