NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



8,35 



This family offers the greatest resemblances to the Diaperoeciidae. It differs 

 from it chiefly in the more constant form of the ovicells and in the presence of 

 mesopores. 



This family includes a great numlier of zoarial forms classified by Gregory 

 in his families of Petaloporidae and Zonatulae, in which the ovicell is identical. 

 It includes also the forma Multi<-are(t D'Orbigny, 1852. The ovicell of the latter 

 and also that of Zonopora of the same author have been discovered by Canu in 

 the French Cretaceous. 





Jg^ :^\:^-^\ 



Fx12 



FIG. 277. Forma MuHicavea D'Orbigny, 1852. 



A-F. MuUit-avca magnified D'Orbigny, 1852. A, B. Zoaria, natural size. C. Transverse sec- 

 tion of a branch, enlarged. D. Aspect of the zoarial surface, enlarged. E. Longitudinal section. 

 lA-E, after D'Orbigny, 1852.) F. An ovicelled specimen from the Maastrirhtinn of Royan, 

 France. 



The genera recognized by Gregory are only zoarial forms. Thus the form 

 called Cavaria, with hollow zoarium. presents ovicells of Ascosoeciidae (as Para- 

 scosoecia consimilis Ulrich, 1882), of Leiosoeciidae (as Parlciosoecia jacksonica. new 

 species), and Tretocycloeciidae (as Partrrtocycloecia exilis, new species). 



Moreover, the zoarial aspect called Zonopora results simply from the bifur- 

 cation of the mesopores: it can therefore occur without importance in any family 

 containing adventitous tubes. 



