118 DR. GWYN JEFFREYS ON THE MOLLTJSCA OF THE [Feb. 19, 



R. costulata of Alder and probably also R. ovatella of Forbes are 

 varieties of R. similis ; and there are several other synonyms. In my 

 paper on Piedmontese Mollusca (nearly thirty years ago) I erro- 

 neously referred this species to R, oblong a of Desmarets ; I now 

 consider that so-called species a variety of R. membranacea. R. cos- 

 tulata of Risso appears to be the same species as R. costata of 

 Desmarets, which is R. variabilis of v. Miihlfeld. But it would cause 

 unnecessary confusion if these names were interchanged. Let usage 

 prevail. " I care not for their names." 



Specimens of R. costulata, Alder, from Cadiz, are undistinguishable 

 from those of R. similis except in colour. The peculiar characters 

 of both are the constriction of the body-whorl and mouth, and the 

 spire tapering to a fine point. Some specimens of the typical form 

 are ribless and nearly smooth, and others of the variety costulata 

 are broader and more ventricose in the middle. 



• 20. Rissoa violacea, Desmarets. 



R. violacea, Desm. in Bull. sc. soc. phil. Paris, 1814, p. 8, pi. i. 

 17: B. C. iv. p. 33 ; v. p. 208, pi. lxvii. f. 9. 



♦Porcupine' Exp. 1870: Atl. St. Vigo B. ; Med. Algeciras B., 

 G. Tunis. 



Distribution. Loffoden Isles to the Mediterranean and Adriatic, 

 Black Sea, Madeira, and Canaries ; 0-108 fms. 



Fossil. Pliocene : Italy. Post-tertiary : Norway, Scotland and 

 Ireland, Nice, Leghorn, Ischia, Rhodes ; 0-100 ft. 



At least ten synonyms, including R. li/acina, B.ecluz, H. rufi- 

 labrum, Leach apud Forbes and Hanley, Persephone riifilabris, 

 Leach, and R. porifera, Lovtm. 



Variable as to size and the strength of sculpture, like all other 

 littoral and prolific species. 



21. Rissoa parva, Da Costa. 



Turbo parvus, Da Costa, Brit. Conch, p. 104. 



R. parva, B. C. iv. p. 23, pi. i. f. 1 ; v. p. 207, pi. lxvii. f. 3, 4. 



1 Porcupine ' Exp. 1870 : Atl. St. Vigo B., 13, 36 (intermediate 

 between the typical form and the variety interrupta), Gibraltar B. 

 (monstr.). As var. interrupta, 1869 : Donegal B., L. Swilly. 

 1870: Atl. Vigo B. (semicostata), 16; Med. Algeciras B. (senri- 

 costata), 50, Adventure Bank. 



Distribution. Typical form and var. interrupta. Scandinavia from 

 Vadso southwards, Great Britain and Ireland, Heligoland, Holland, 

 France, Spain, Portugal, Italy, Dalmatia, Greece, Algeria, Madeira, 

 Canary Isles, and ' Valorous ' and ' Travailleur ' Expeditions ; 0- 

 J785 fms. (at great depths transported from the littoral and lami- 

 narian zones). 



Fossil. Pliocene or Post-tertiary : Scandinavia, Great Britain and 

 Ireland, Biot, Nice, Italy, Cos, and Rhodes ; 0-200 ft. Not as 

 Turbo interruptus of Adams from the Tertiary formation of N.AV. 

 Germany, described and figured by Philippi. 



