PLATE XXL 
Page. 
Fig. 1. Mytilus Biysbyi, L. G. <le Koninck — Internal cast, lateral view... ... ... 227 
Fig. la. The same, seen from the cardinal side ... ... ... ... ... ... 227 
Fig. 2. Mytilus crassivenfe?', L. G. de KouiiiL-k --Internal cast, lateral view ... ... 227 
Fig. 2a. The same, seen from the cardinal side ... ... ... ... ... ... 227 
Fig. 2b. The same, seen from the ventral side ... ... ... ... ... ... 227 
Fig. 3. Aviciilopecte?ile>iiusculus,S.'D. Dana. — Cast, with a portion of the shell preserved 228 
Fig. 4. Aviculopecten Fittoni, J. Morris — Lateral view of specimen, copied from J. 
Morris ... ... ... ... ... ... ... ... ... ... 237 
Fig. 4«. Lateral view of internal cast ... ... ... ... ... ... ... 237 
Fig. 5. Aplianaia Mitcbellii,F. McCoj — Internal cast, lateral view ... ... ... 239 
Fig. 5a. The same, seen from the dorsal side ... ... ... ... ... ... 239 
Fig. G. Aphanaia gigantea, L. G. de Koninck — Internal cast, seen from the side of the 
smaller valve ... ... ... ... ... ... ... ... ... 240 
Fig. Ga. The same, seen from the dorsal side ... ... ... ... ... ... 240 
