1883.] 'lightning' AND ' porcupine' EXPEDITIONS. 101 



/ 16. Trochus delicatus', Jeffreys. (Plate XX. fig. 7.) 



Shell forming a depressed cone, thin, opaque, rather glossy : 

 sculpture, on tlie body or last whorl only, fine and close-set spiral 

 stria?, crossed by equally numerous curved longitudinal striae ; the 

 spiral striae are wanting below the suture, and are few and slight on 

 the base ; periphery bluntly keeled ; umbilicus partly enclosed by a 

 small ridge, which extends through the middle of the inside and 

 becomes thicker outside ; all the upper whorls are quite smooth : 

 colour milk-white : whorls 4^, moderately convex, the last occupying 

 about three fourths of the shell ; apex somewhat twisted : mouth 

 roundish : outer lip thin : inner lip filmy : inside slightly nacreous : 

 umbilicvs small but deep. L. 0'075, B. 0'125. 



'Porcupine' Exp. 18/0: Atl. St. 24. A single and imperfect 

 but characteristic specimen. 



/1 7. Trochus vARirs, Linne. 



T. varius, L. S, N. p. 1229 ; Philippi, Moll. Sic. i. t. x. f. 19. 



' Porcupine ' Exp. 1870 : Atl. St. Vigo B. 



Distribution. Gulf of Gascony (de Folin), Mediterranean and 

 Adriatic ; 0-2 fms. 



Fossil. Pliocene: Italy. 



T. roissyi, Payraudeau, and T. varians, Deshayes. Var. Gibbula 

 elata, Brusina. 



1/ \8. Trochus cinerarius, Linne. 



T. cinerarius, L. S. N. p. 1229 : B. C. iii. p. 309; v. p. 203, pi. 

 Ixii. f. 3. 



' Porcupine' Exp. 1869 : St. L. Foyle, near Belfast. 1870 : Atl. 

 Vigo B., 26. 



Distribution. Iceland, Finmark, and Faroe I. to the Lusitanian 

 coasts, Mogador, Mediterranean, Adriatic, and Black Sea ; 0-60 

 fms., inhabiting the littoral and laminarian zones. 



Fossil. Pliocene : Red Crag. Post-tertiary : Scandinavia and 

 British Isles ; 0-600 ft. 



Variable in size and the comparative height of the spire. 



Synonyms rather numerous. Among these or as representing 

 varieties are Trochus lineatus of Da Costa, T. philippii of Aradas, 

 and T. cineroides of Searles Wood. Not T. cinerarius of Born, 

 Brocchi, Olivi, O. G. Costa, or Bellardi. My variety variegata is 

 not Monodonta eegyptiaca of Payraudeau, which is Trochus fanulum 

 of Gmelin. 



19. Trochus villicus, Philippi. 



T. villicus, Phil. Moll. Sic. ii. p. 152, t. xxv. f. 14. 



' Porcupine ' Exp. 1870 : Atl. St. Vigo B. ; Med. 50. 



Distribution. Mediterranean, Black Sea, and Adriatic ; 0-20 fms. 



Closely allied to T. cinerarius, and perhaps a variety of it. It 

 may have been included in Linne's too short description of that 

 species. 



' Delicate. 



