NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



79 



Genotype. Membranipora catenularia, Jameson, 1814. 



Range. Cretaceous-Recent. 



The French author added that in creating the genus Pyripora in the Prodrome 

 of Stratigraphic Paleontology he had placed there all species with colonies formed 

 of isolated cells, but that now in the restriction of families it was necessary to 

 give more special characters, and that therefore he would restrict Pyripora solely 

 to species with large open cells without special pores. 



History and discussion. In 1847, when D'Orbigny published his Prodrome, it 

 was the author's idea that this was only a provisional work which later researches 

 would modify. D'Orbigny's supplementary work classifying both fossil and 

 recent bryozoa was published in the Paleontologie Franchise of 1850 to 1852. This 



A 55 



FIG. 20. Genus Heterooccium Hincks, 1892. 



A, B. Heterooedum amplcctens Hincks, 1892. 

 A. Several zooecia, X 55. The small denti- 

 cles are not only seen at the margin of the 

 membranous area but are also visible through 

 the calcined wall of the frontal surface. The 

 acanthostegous ovicell (ov. a.) has its cavity 

 between the spines and the ectocyst. B. The 

 frontal wall of a zooecium, X 75, seen from the 

 internal surface. (After Levinsen,1909.) 



FIG. 21. Genus Pyripora D'Orbigny, 1852. 

 A, B. Pyripora catenularia Jameson, 1814. A. Lin- 

 ear form, X 25, with regenerated zooecia. B. Ex- 

 pansion of zooecia, X 25, with all of them regen- 

 erated. (After Hincks, 1880.) 



superseded the Prodrome, and of course is alone to be considered. In this special 

 case, priority has no significance and can not be invoked for the date of a genus or 

 species. 



Similarly, MacGillivray has given many definitions of his genus Hiantopora, 

 and it becomes a question which one of them is to be recognized. Logically it 

 should be the last one which is the result of the most detailed and complete studies 

 of the author. 



In 1852 D'Orbigny cited four species of Pyripora, three fossil forms, Escha- 

 rina crenulata Reuss, Escharina perforata Reuss, Criserpia pyriformis Michel in, 

 and one recent, Pyripora ramosa D'Orbigny; but as he did not cite a type, the 

 choice of one therefore becomes necessary. Common sense would indicate that his 

 recent species, which has always been considered as synonymous with Membrani- 



