MOLLUSORPMDU ‘ROUSSIEEOS 
Planche 31. 
Classe GASTROPODA (Cuvier) 
do ———— DOS 
ORDRE I. Prosobranchiata FAMILLE : Littorinid:æ 
SECTION B. Iolostomata GENRE : HRissoa 
MANS, Rissoa variabilis Mühlfeld .var. elongata Monterosato. 
4, — — — (type) 283 
6, 7, 8, 9. 10, — == — .var. brevis Monterosato. 
D, 12, 29/7, —  ventricosa Desmarest. 247 h 
14, ES — — .var. subventricosa Cantraine. 
16, 17, 18, 19, 20, — lineolata Michaud. 2:77 
Bucquoy, Dautzenberg & Dollfus. 
