PLATE 49. 
Fig. 1. Tellinomya nucleiformis. 
1. A cast of the left valve. 
Fig. 2 a - e . Modiolopsis? dubius. 
2 a. The right valve of a specimen which is slightly imperfect at the posterior extremity. 
2 6. Cardinal view of the same. The apparent gaping at the posterior extremity is due to 
imperfection of the specimen. 
2 c. The right valve of this species. 
2 d. The left valve of a larger individual. 
2 e. A fragment of limestone preserving the separated valves of several individuals. 
Fig. 3 a - d . Anatina? sinuata. 
3 a. The right valve? of a specimen in which the two extremities are imperfect. 
3 b. Cardinal view of the same. The compression of the anterior extremity is not distinctly 
represented. 
3 c. The right valve? of a specimen from which the shell is nearly exfoliated, and the beaks 
broken off. 
3 d. Profile view of the same 
Fig. 4. Megambonia suborbictjlaris. 
4 a. The left side of the cast, showing the muscular impression. 
5 b ( by error for 4 b on plate). Profile view from the posterior side. 
Fig. 5. Megambonia spinneri. 
5 a. The left side of the cast, showing the form, the muscular scar, and elevation of the beak. 
4 6 (by error for 5 6). Profile view from the posterior side. 
5 c. Cardinal view, showing the prominence of the muscular scars. 
Fig. 6. Avicula obscura. 
6. Interior of a right valve, having the anterior wing nearly obliterated, and the other broken 
off at some distance from the extremity. 
Fig. 7 & 8. Megambonia ayiculoidea. 
7 a. The left valve of a young shell. 
7 6. The left valve of a larger individual. 
8. A full-grown? individual preserving in part the anterior and posterior extensions, the shell 
being removed from the central prominent part of the fossil. 
Fig. 9. Megambonia riiomboidea. 
9. The left valve, imperfect at the posterior side, and also at the anterior side, though the 
latter is not shown in the figure. 
