NORTH AMERICAN EARLY TERTIARY BRYOZOA. 593 



The ovicell is recumbent. The budding is double, terminal and superficial. 

 The zooecia are more or less erect and cumulate. 



Figure 176 illustrates the anatomical knowledge of this important family. 



The only known larva is of the schizostomatous group. Levinsen in 1909 

 created a special family for the holostomatous group, which is perhaps a valid one, 

 but as we are ignorant of the larva we have not recognized it, Our clithridiate 

 group is perhaps also a distinct family. 



The budding is superficial ; it occurs on all the zooecial walls. Certain frontal 

 pores are therefore not areolae but veritable septules. The consequence is the piling 

 up or accumulation of the zooecia, In the distal budding the zooecia are always 

 oriented : in the superficial budding they are arranged in all directions. However, 

 the zooecia issuing from the larva and those which are in contact with the sub- 

 stratum are always oriented. In some rare fossil species the cumulate zooecia are 

 rare. The power of superficial budding is then apparently not spontaneous, but 

 it is generalized gradually. 



Among the Cheilostomes the Cellepores have appeared last (about the Lutetian) 

 and in the tropical seas. They are multiplied to excess in the Miocene. At pres- 

 ent they have overrun the seas, where often they multiplied in immense numbers; 

 they dominate the recent fauna by their extraordinary numbers. In the size of 

 their zoarium, the extreme rapidity of their budding, the infinite pliancy of their 

 aptitude for adaptation, and in their astonishing fertility, they show an over- 

 whelming vitality. They accommodate themselves to all areas, to all depths, to all 

 temperatures, and to all kinds of foods. These are the most vigorous and the most 

 perfected of all the bryozoa. 



Historical. An authoritative history of the genus Ccttepom was given in 1852 

 by D'Orbieny. 1 He attributed it to Fabricius, 1780; this it appears was an error 

 that Hincks repeated later; Levinsen, in 1909. noted that its founder was Linnaeus 

 himself, in 1767. In 1913 Waters rewrote the history with a scrupulous exactitude; 

 his conclusion was that the interpretation of the poor figures of the early authors 

 has caused most vexatious confusion and that it is more scientific to adopt the types 

 of Busk and Hincks, who recognized the true nature of the bryozoa, 



It was in 1836 that Milne-Edwards, in the second edition of "Animaux sans 

 vertebres" of Lamark. gave the name of Cellepores to the species with cumulate 

 zooecia. Whether wrong or right, this opinion has prevailed in the science. There 

 has been nothing of scientific interest added to the discussion after three-quarters 

 of a century. Moreover, the word indicating only a special and complex mode of 

 budding, ought necessarily to disappear from the generic nomenclature, since by 

 definition even, a genus is a union of creatures having the same functions, the bud- 

 ding being only one of these functions. 



We have preserved the word C'ellepora as an invalid genus only for the species 

 requiring further study, as we are often forced to do in paleontology. 



1 Paleontologie francaise, Terrains Cretaces, p. 389. 

 55S9& 19 Bull. 106 38 



