738 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



penclicularly to the zoarial margins and their traces are indicated in thin sections 

 by their peculiar undulations (fig. 16) regularly spaced. The reader will better 

 comprehend this peculiar arrangement by consulting figure 12 which shows the 

 interior of the tubes obtained by the ablation of one of the two lamellae of the 

 zoarium. 



The oeciostome is smaller than a tube as in the genus Microccia, but it is turned 

 toward the base; it is isolated and is never supported on the peristome of a tube. 



In spite of the large transverse wrinkles which ornament the tubes, the tan- 

 gential section indicates that their walls are absolutely identical with those of all 

 the other C'yclostomata (fig. 11). 



When the transverse section is indeed perpendicular at the time of the folding 

 and at the zone of growth (fig. 14). the tubes adjacent to the basal lamella are 

 alone visible. In the other case the tubes appear formed on the basal lamella and 

 above their ramifications form the peristomial lines (fig. 16). 



Affinities This species differs from Re.tiwlipora mummulitonim D'Orbigny, 

 1852, and from Ifi'tir-nlijiorfi pVcata Canu, 1000, of the French Lutetian, in its dif- 

 ferent micrometric measurements and in its larger wrinkles. Moreover, the ovicells 

 of the two latter species are not known. 



This species is quite characteristic of the Vicksbnrgian. 



Occurrence. Vicksburgian (Eed Bluff clay) : Seven and one-half miles south- 

 west of Bladen Springs, Alabama (rare) ; one-fourth mile west of Woodward, 

 AVayne county, Mississippi. 



Vicksburgian (Marianna limestone) : Murder Creek, east of Castlebnry, 

 Conecuh County, Alabama (common) ; west bank Conecuh Eiver, Escambia 

 County, Alabama (common) ; Salt Mountain, 5 miles south of Jackson, Alabama 

 (very rare) ; near Claiborne, Monroe County. Alabama (common) ; one mile north 

 of Monroeville, Alabama (very common). 



Gotypes.C&t. No. 65405. U.S.N.M. 



Family DIAPEROECIIDAE Canu, 1918. 



Anatomical hiliHdiiniiilnt. 1887. WATERS, On tertiary Cyclostomatous Bryozoa, Quarterly Jour- 

 nal of the Geological Society, vol. 43, pi. 18. figs. 5, 0, 13, 14. 15. 1903. WATERS, Bryozoa 

 from Franz Josef Land, Journal Liunean Society, London, vol. 28, p. 173, pi. 19', tigs. 1-13. 

 1905. WATERS, Bryozoa from near Cape Horn, Journal Linnean Society. London, vol. 29, p. 247, 

 pi. 29, figs. 10-14. 1914. WATERS, The Marine Fauna of British East Africa and Zanzibar, 

 Proceedings of the Zoological Society of London, p. 836. 



The-ovicell is formed after the calcification of the distal tubes. It is an irreg- 

 ular, snbglobular elevation, placed among many tubes which project on the ovicell 

 itself. The oeciostome is submedian, transverse, salient, often isolated, generally 

 proximally directed. 



We do not know the larva, but this family appears different from the Tubu- 

 liporidae in its oeciostome which is often isolated and in its expansion by which it 

 completely surrounds the tubes or the fascicles. 



