1884.] * lightning' AND 'PORCUPINli' EXPEDITIONS. 117 



Distribution. Lisboii (3icJ.«rfrew), Mediterranean and Adriatic; 

 4-18 fms. 



Fossil. Pliocene : Central and Southern Italy. Post-tertiary : 

 Rhodes and Cyprus. 



lu the shape and columellar fold this species is allied to the 

 next. 



17. RissoA MEMBRANACEA, Adams. 



Turbo membranaceus. Ad. in Tr. Linn. Soc. v. p. 2, t. i. 

 f. 12, 13. 



R. membranacea, B. C. iv. p. 30 ; v. p. 208, pi. Ixvii. f. 8. 



'Porcupine' Exp. 1869: St. Donegal B. 1870: At). 2fi. 



Distribution. Throughout the European seas from the LofFoden 

 Isles southwards. Black Sea, the African coasts of the Mediterranean, 

 and Canaries (Schwartz) ; 0-600 fms. 



Fossil. Pliocene: Italy. Post-tertiary: Scandinavia, Scotland, 

 Ireland, Selsea, Martigues, Rhodes; 0-100 ft. 



The varieties and names of so-called species which I consider 

 varieties are very numerous ; I have noted more than a score of 

 such synonyms. R. sjylendida of Eichwald appears to differ only in 

 having a shorter spire and rows of small purplish spots, arranged 

 in the same way as in a pretty Algerian variety of B. montaouti. 



\/ 18. RissoA VARIABILIS, Megcrlc v. Miihlfeld. 



Turbo variabilis, Meg. v. Miihlf. Ges. IS'at. fr. zu Berhn, 1829, 

 i. p. 212, t. i. (7), f. 9, o, b. 



'Porcupine' Exp. 1870: Med. St. Algeciras B. 



Distribution. Atlantic coasts of Spain and Portugal, Mediter- 

 ranean, Adriatic, and Black Sea; 10-120 fms. 



Fossil. Miocene : Madeira {Mayer). Pliocene : Italy. Post- 

 tertiary : Nice, Leghorn, Sicily, Rhodes. 



R. costata of Desmarets and R. desmaresti of Forbes. Mon- 

 terosato says (in his letter) that perhaps Eulima cingulata of 

 Requien may have been an elongated ribless variety of the present 

 species. Such attempts at identifying doubtful species of obscure 

 authors are more ingenious than useful. 



R. variabilis deserves its name, as regards the length of spire and 

 strength of sculpture. 



^ 19. RissoA siMiLis, Scacchi. 



R. similis, Sc. Cat. conch. Neap. 1836, p. 15; Phil. Moll. Sic. ii. 

 p. 124, t. xxiii. f. 5. Var. as R. costulata, B. C. iv. p. 35 ; v. 

 p. 208, pi. Iviii. f. 1. 



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



Distribution. From Scarborough and along the western coasts of 

 France and Spain to the Mediterranean and Adriatic, Madeira and 

 the Canaries ; 0-1.50 fms. 



Fossil. Miocene : Madeira. Pliocene : Italy. Post-tertiary : 

 Selsea, Leghorn, Ischia, Rhodes, and Cyprus. 



