CHARACTERISTIC DEEP-SEA TYPES. BRYOZOA. 79 



of the deep-water species belong to the section of the Cheilosto- 

 mata, while the Ctenostomata have comparatively few represen- 

 tatives. Busk says that the shallower-water species appear to 

 have the widest geographical distribution. That is apparently 

 not the case with the species collected by the " Blake." 



According to Professor Smitt's Reports we may mention 

 among the " Blake " Bryozoa the cosmopolitan Crisia eburnea, 

 the form known as C. denticulata (Figs. 323, 323 a), and, from 

 306 fathoms, the Scandinavian Diastopora repens (Figs. 324, 

 324 a), a well-known ramified form creeping on Terebratula eu- 

 bensis. This species is also characteristic of the crag, and per- 

 haps identical with a cretaceous form. It seems as if the species 

 of this group assumed a somewhat more elongate and simpler 

 form in proportion to their bathymetrical range. Busk, from 

 an examination of the extensive collection of the " Challenger," 

 considers the species of Farciminaria (Figs. 325, 325 a) as the 

 most characteristic of the abyssal bryozoans, the preeminent 

 forms of the delicate and flexible types inhabiting the tranquil 

 depths of the ocean. 



Membranipora canariensis (Fig. 326), a widely spread spe- 



Fig. 326. Membranipora Fig. 327. Cellularia cervi- Fig. 327 a. Cellularia 



canariensis. l ^&. cornis. f. cervicornis. Magnified. 



(Smitt.) 



cies, found in both hemispheres, and common in the tertiaries l 



1 There are among the Florida and period, and about five either the same or 

 West Indian bryozoans no less than sixteen closely allied to cretaceous types, 

 species identical with those of the tertiary 



