Plate 6 



Figures 1 a-c. Discorbis nitida (Williamson). X 75. Coast of Belgium, a. 

 dorsal view; h, ventral view; c, peripheral view. 



2 a-c. Discorbis obtnsa (d'Orbigny) (?). X 55. Casco Bay, Mo. a, 



dorsal view; b, ventral view; c, peripheral view. 



3 a-c. Discorbis orbicularis (Terqueni). X 75. Montego Bay, Ja- 



maica, a, dorsal view; b, ventral view; c, peripheral view. 



4 a-c Discorbis (f) praegeri {HcTon-AWen and FjarlsLiid) . X 100. (After 



Heron-Allen and Earland.) Clare Island Region, Ireland, o, 

 dorsal view; b, ventral view; c, peripheral view. 



5 a-c. Discorbis parisicjisis {d'OThiguy)(?). X 75. Coast of Belgium. 



a, dorsal view; b, ventral view; c, peripheral view. 



151 



