NORTH AMERICAN EARLY TERTIARY BRYOZOA. 119 



characters of the Membranipore group and not of the Onychocellidae. The dorsal 

 olocyst is very thin, and easily worn away, allowing the substratum to appear. We 

 have observed some cases of total regeneration and deformed zooecia are not rare. 



Affinities. It may be that this species ought to be classed in Hincfcsina; 

 however, the great development of the cryptocyst and the entire absence of 

 avicularia will not allow us to place it there. This is a problem which can find its 

 solution only in the study of an identical or closely allied recent species. 



The zooecia resemble those of Amphiblestrum pcrfragile MacGillivray, 1868. 

 figured by Ortman in 1890. The present species differs in its nonbilamellar zoarium 

 and in the absence of a large interzooecial avicularium. MacGillivray's species may 

 belong to a new genus. 



Occurrence. Middle Jacksonian: Near Lenuds Ferry, South Carolina (com- 

 mon) ; Wilmington, North Carolina (very rare) ; Eutaw Springs, South Carolina 

 (rare). 



Holotype.Cut, No. 63885, U. S. N. M. 



OGIVALINA ELONGATA. var. MINOR, new variety. 



Plate 23, figs. 9, 10 



This variety is well founded, for no intermediate specimens have been noticed. 

 However, it can not be considered a smaller distinct species, for it occurs at. the 

 same localities as the species itself. 



0=0.25-0.50 mm. (Z;2=0.40-0.43 mm. 

 Measurements.-Opesm Zo= 0.17-0.20 mm. ia i?3=0.22-6.26mm. 



Occurrence. Middle Jacksonian: Wilmington. North Carolina (rare); near 

 Lenuds Ferry, South Carolina (rare) ; Eutaw Springs, South Carolina (rare). 

 Lower Jacksonian (Moodys marl) : Jackson, Mississippi (rare). 

 Cotypes. Cat. No. 63886,' U.S.N.M. 



Genus MEMBRENDOECIUM Canu and Bassler, 1917. 



1917. Memlrcndoecium CANU and BASSLER, Synopsis of American Early Tertiary Cheilos- 

 tome Bryozoa, Bulletin 96, United States National Museum, p. 17. 



Ovicell endozooecial. Small simple interopesial avicularia. Dietellae present. 

 No spines. 



Genotype. Amphiblestrum pa-pill atum- Busk, 1884. 



Range. Midwayan Eecent. 



In Membrendoeciwn we have a very natural genus with exact characters. The 

 recent species Amphiblestrum papillatum is closely related to our fossil forms, but 

 unfortunately this species is very rare and its structure is imperfectly known. Its 

 avicularia have much the aspect of our species, and Busk writes of it " S m; ill avicu- 

 laria having a triangular mandible, on small papillary eminences seated in the 

 angular interzooecial spaces." 



In its exterior aspect this genus recalls Pyriporella Canu. 1911, but the latter 

 has hyperstomial ovicells. The structures which Canu has identified as vibmcula 



