PLATE 23. 



Piige 



Fig. 1 & 2. Strophodonta leaven worthana. 189 



1 a. b, c. Ventral, dorsal, and profile views of an entire specimen. 



2 o, b. Dorsal and profile views of a full-grown individual. 

 2 e. Enlargement of the fine equal striae. 



Fig. 3. Strophodonta beckii. ' 191 



3. A cast of the interior of the dorsal valve. 



Fig. 4,5 & 7. Strophodonta pttnctulifera. 188 



4 a, b. The interior and profile view of the dorsal valve. 



4 c. Profile view of a mere gibbous specimen. 



5 c. Cardinal view, showing the area enlarged. 



7 e. Enlargement of striae which are scarcely exfoliated, showing pustulose points, some of 

 which are punctate at their extremities. 



Fig. 6. Strophodonta geniculata. 483 



6 a, b. Ventral and dorsal views of a small individual. 

 6 c. Profile of the same. 



Fig. 1 a - g. Orthis strophomenoides. 177 & 4H1 



7 a. An imperfect dorsal valve of this species. 



7 b. Enlargement of the surface striae from 7 a. 



7 c. A cast of the dorsal valve, showing the vascular and muscular impressions in a great 

 degree of perfection. 



7 d. A similar specimen, showing variations in the markings. 



7 g. A similar cast, showing the muscular impressions, and the vascular impressions of the 

 ovarian spaces. 



7/. A cast of the ventral valve, showing the muscular and vascular impressions. 



Figures 2 a, b and c, and fig. 3, were drawn by Mr. F. B. Meek; the remainder, by Mr. Whitfiei.d. 

 The upper figure of -3 was intended as a correction (subsequently added ) of the erroneous form of 

 crenulations in the hinge of the one below. 



