PLATE 139. 



N.B. — The signification of the characters is the same in all the figures (compare p. 718). 



a. Northern polar spines. 



b. Northern tropical spines. 



c. Equatorial spines. 



d. Southern tropical spines. 



e. Southern polar spines. 



Belonaspida et Hexalaspida. 



Fig. 1. Hexacolpus nivalis, n. sp., 



Fig- 2. Hexalaspis heliodiscus, n. sp., 



Fig. 3. Hexaconus ciliatus, n. sp., 



Fig. 4. Hexaconus serratus, n. sp., 



c, Central base of an equatorial spine ; d, central base of a tropical spine. 



Fig. 5. Hexaconus coronatus, n. sp., . 



Fig. 6. Hexaconus velatus, n. sp., . 

 Marginal view of the shell. 



Fig. 7. Hexaconus vaginatus, n. sp., . 



Fig. 8. Thoracaspis hipennis, n. sp., . 



Fig, 9. Belonaspis datura, n. sp., , 





Diam. 



Page 



X 



300 



880 



X 



300 



875 



X 



300 



876 



X 



300 



877 



X 



300 



877 



X 



300 



877 



X 



300 



877 



X 



300 



862 



X 



400 



863 



