NORTH AMERICAN EAICLY TERTIARY BRYOZOA. 



317 



Occwvencp. Upper Jacksonian (Ocala limestone): Chipola River, east of 

 Marianna, Jackson County, Florida (very rare); Old Factory, 14 miles above 

 Bainbridge, Georgia (very rare). 



Holoti/pc.C-At. No. 64036, U.S.N.M. 



Genus ASPIDELECTRA Levinsen, 1909. 



UiblioyrapJii/ (Zoological). 1903. NOKMAN, Notes on the Natural History of East Fiunmrk. 

 Anuals Magazine Natural History, ser. 7, vol. 12, pi. 8, fig. 1909. LEVINSEN, Morphological 

 and Systematic Studios Cheilostomatous Bryozoa. pi. 160. 



" The proximal part of the zooecium with one or two thick, projecting, hollow 

 spines; the frontal shield perforated by slits: each distal wall with two multi- 

 porous septular disks, and the distal half of each lateral wall with a single septula, 

 the aperture in the frontal shield with an opercular valve; no avicularia ; no 

 ovicell." (Levinsen.) 



FIG. 88. Genus Aspidetectra Levinsen, 1909. 



A-E. Aspidelecini iiirlolontlm Busk. 1852. A. B. Zooeciuin, X 20, and zoarium, natural size. 

 (After Hincks, 1880.) C. Lateral view of a zooecium, X 40. D. Lower side of the zoarium, > 

 12. (C. D after Levinsen, 1894.) E. Structure of the costules. (After Norman, 1903.) 



Genotype. Aspidelectra (LeprttUa) melolontTta Busk. 1852. 



Levinsen thought that this genus belonged to the Electrinidae. It is not rep- 

 resented in the American Eocene, and we cite it to show how heterogeneous the 

 Cribrilinidae are, and to suggest the importance of the ontogenetie works which 

 'might be undertaken on this subject. 



Family ACROPORIDAE Canu, 1913. 



The zooecia are indistinct and their frontal is thickened. The ascopore, per- 

 forating the frontal, opens into the zooecia below the operculum. The ovicell is 

 hyperstomial. deeply immersed and invisible exteriorly. The apertura is buried 

 at the bottom of a long peristomie. There are some frontal avicularia and some 

 peristomial avicularia. 



The characteristics of this family are not yet sufficiently studied; the recent 

 specimens are rare and the sections made of the fossil forms are often difficult to 

 interpret. 



