PLATE 9. 



/ 



Fig. 1 & 2. LlNGCLA CENTRILINEATA. 



1. A small imlividual of this species. 



2. A larger specimen of the same. 



I'jgc 



155 



Fig. 3, 4 & 5. LiNQULA PERLATA. 15() 



4. An individual of medium size, preserving the two valves. The outer shell is partially e.\- 



foliatcd from the central part of the valve, 



;!. Profile of the same specimen, showing the convexity of the valves. 



5. The lower ])art of a larger valve having the stria; more distant, very thin and sharply 



elevated, while towards the margin they are more closely arranged. 



i") a. Knlargement of the concentric lamella'. ' 



Fig. & 8. LiNGULA RECTILATER/. 15(5 



(). An individual of medium size. 



8. A large Individual of the same species. 



Fig. 7, 9 & 11. LiNGULA SPATHATA. 157 



9. A large individual having the upper part of the shell hrokcn off. 



7 & 11. Two views of a specimen having the base broken off. The convexity of the two valves 

 is more than one-third the greatest width of the shell. 



Fig. 10. LiNGULA SPATIOSA. 158 



10. The shell, natural size. 



10 a. A portion of the surface enlarged. 



Fig. 13 - 15, & 16 a. Discina biscus. 195 



13. The lowi.T valve partially exfoliated, and showing radiating stria-. 



14. Interior of th" lower or ventral valve, showing the lamellose structure and radiating striie. 

 [ In the figure the stria; are too regular, and should be represented as bifurcating to- 

 wards the margin.] 



1-5. A lower valve (with the margins slightly exfoliated ) , preserving nearly entire the con- 

 centric lamellose striae. 



1('> a ( Error for 1-5 o). Profile of the lower valve, showing the convexity. 



15 b. Enlargement of the lamellose stria;. 



l.j a ( Error for 14 a). Enlargement of the radiating stria; of fig. 14. 



Fig. \i, 16 & 17. Discina conradi. Kil 



12 Exterior view of the lower valve ( improi)erly rei)rcsented without the foramen). 



12 a. Enlargement of the surface of the same. 



10. Dorsal valve having the outer shell exfoliated, and showing radiating stria' wliicb bifurcate 

 towards the margins. 



17. Enlargement of the stria>. 



17 a. Profile view of the dorsal valve. 



