PLATE 96, 
Pago 
4*29 
Fig. 1 - 6. CyRTIA llOSTRATA. 
1 a, b. Dorsal and cardinal views of a young specimen, which has six plications on each side 
of the mesial fold. 
2 a, b. Dorsal and front views of a larger specimen. 
2 c, <1. Profile and cardinal views of the same specimen. 
8 a, b. Cardinal and front views of another individual, with a higher area and less extended 
hinge-line. The beak in fig. 3 a , as represented, is not sufficiently elevated. 
4 a, b. Ventral and dorsal valve of an old specimen. 
4 c, d. Profile and cardinal views of the same specimen. 
5. Interior of the dorsal valve. 
6 a, b. The exterior and interior of a dorsal valve of this species. 
Fig. 7 a-/. Spirifer submucronatus. 419 
7 a, b. Ventral and dorsal views of a specimen of this species. 
7 c. A specimen with one of the cardinal angles more extended. 
7 d. Front view of the preceding. 
7 e. Profile view of a specimen of this species. 
7 /. The interior of the ventral valve. 
Fig. 8 a - e. Spirifer tribulis. 420 
8 a, b. Ventral and dorsal views of a specimen of ordinary size. 
8 c. Front view of a specimen which is less gibbous than usual. 
8 d. Profile view of a more gibbous specimen. ( The dorsal valve is represented as too convex.) 
8 e. An enlargement of the surface, showing the fine concentric and radiating stria;. 
Fig. 9 a - h. Spirifer cumberlandi2e. 421 
9 a, b. Dorsal and ventral views of a large individual, showing the foramen almost entirely 
closed. 
9 c. Front view of another individual. 
9 d. Profile view of the specimen. 
9 e. Ventral view of a specimen from the upper part of which the shell is removed, showing 
the cast of the muscular area and the rostral cavity. 
9/. Interior of the dorsal valve, showing the cardinal and crural processes, with the dental 
fossets. 
9 g. Interior of the ventral valve, showing the partial closing of the foramen, with a perfora¬ 
tion at the summit, the dental lamella;, etc. 
9 h. View of a cast of the internal spiral appendage, probably of this species. 
