PLATE 139. 



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



a. Northern polar spines. 



b. Northern tropical spines. 

 i 1 . Equatorial spines. 



d. Southern tropical spines. 



e. Southern polar spines. 



BELONASPIDA et HEXALASPIDA. 



Diam. Page 



Fig. 1. Hexacolpus nivalis, n. sp., . . x 300 



Fig. 2. Hexalaspis heliodiscus, n. sp., * 300 8 ?5 



Fig. 3. Hexaconus ciliatus, n. sp., . x 300 876 



Fig. 4. Hexaconus serratus, n. sp., . x 300 877 

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



Fig. 5. Hexaconus coronatus, n. sp., . x 300 877 



Fig. 6. Hexaconus velatus, n. sp., . x 300 877 

 Marginal view of the shell. 



Fig. 7. Hexaconus vaginatus, n. sp., . . x 300 877 



Fig. 8. Thoracaspis bipennis, n. sp., . . x 300 



Fig. 9. Belonaspis datura, n. sp., . x 40 863 



