RISSOIA. 325 



FAMILY RISSOID^E. 

 Genus RISSOIA, Fremenville. 1814. 



R. VENTRICOSA, Desm. PI. 61, fig. 15. 



Whitish or flesh color, with about 12 longitudinal costse, fading 

 on the upper part of the body whorl, finely spirally striate, lip pale 

 violaceous or reddish, with external varix. Length, 8 mill. 



Mediterranean Sea. 



It. subventricosa, Cantraine, is a synonym. 



R. SPLENDID A, EicllW. Pi. HI, fig. 16. 



Scarcely pellucid, polished, white, with faint spiral series of mi- 

 nute chestnut punctations, often obsolete, apex and peristome vio- 

 laceous, ribs about 14, rarely spirally striate. Length, 5*4 mill. 



Mediterranean Sea. 



The synonyms are ft. violcestoma, Kryn., and R. ornata, Phil. 



This species, the preceding and the next, run together in such 

 manner that it is very difficult to distinguish them ; indeed, it is 

 very doubtful whether they are specifically distinct. 



R. PLICATULA, Risso. PL 63, fig. 56. 



Whorls rapidly increasing, flattened, with 12-14 slightly oblique, 

 longitudinal ribs, vanishing on the lower part of the body whorl ; 

 lip strongly varicose ; yellowish white, with fulvous flames between 

 the ribs. Length, 6'3 mill. 



Mediterranean Sea. 



R. VARIABILIS, Muhlf. PL 61, figs. 16, 17 ; PL 65, fig. 4. 



Whorls 7-9, convex, subangulated, with 10-12 longitudinal costee, 

 and punctate, spiral, impressed lines ; lip externally varicose ; 

 whitish, or light brownish, with obscure, punctate, spiral, chestnut 

 lines, and sometimes an obscure basal band, peristome violaceous. 



Length, 9 mill. 



Mediterranean Sea. 



It is It. costata, Desm., It. costulata, Risso, It. Desinaresti, Recluz, 

 It. splendida, Sowb., Turbo Rissoanus, Chiaje, JR. nodulifera, and It. 

 punctata, Kiister, It. protenta and R. neglecta, Locard. 

 ? Monstr. STRANGULATA, Brusina. PL 65, fig. 4. 



Upper portion smooth, middle longitudinally costate, body whorl 

 tumid, smooth, suture deep ; vitreous white, peristome violaceous. 



Length, 4'5 mill. 



Dalmatia. 



Monterosato considers this a monstrosity of R. variabilis. 



