NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



751 



Diameter of the peristome 0.20-0.24 mm. 



Diameter of the apertura__. 0.12 mm. 



-w-^. . , . . 



Distance between the penstomes 1.20 mm. 



Width of the segments of the base _ 0.2(5 mm. 



This species is not as rare as the preceding one, for we possess a score of 

 fragments which has permitted us to make longitudinal sections. The tubes are 

 arranged as in Filisparsa. We have supposed that these are the branches of the 

 base of a Grisulipora, but the discovery of other segments is necessary. 



D'Orbigny named this special arrangement of the biserial zoaria, Unicrisia. 



Occurrence. Vicksburgian (Marianna limestone) : Murder Creek east of Cas- 

 tlebury, Conecuh County, Alabama (rare) ; west bank Conecuh River, Escambia 

 County, Alabama (common). 



Cotypes.G&t. No. 654(30, U.S.N.M. 



DESMEDIAPEROECIA, new genus. 



The ovicell surrounds the fascicles. The surface of the tubes is ornamented 

 with large pores closed by a calcareous lamella. 



FIG. 243. Desmediaperoecia, new genus. 



A, B. Zoarimn natural size and a portion, X 7, of Desmediaperoecia (Tnl>ulii><ini) biiliipli- 

 i-ritu Wafers. 1SS7. C. Portion of xoarium, X 7, of Desmcdiuprnirriit (Tulmlipora) 

 AVaters, 1887 (not D'Orbigny). 



Genotype. Desmediaperoecia (Tubulipora) campicheana Waters, 1887. Mio- 

 cene. Another species referred to this genus is Desmedia-peroeda (Tubulipora) 



liidii I'linilti Waters. 1887. 



We have not observed the species mentioned by Waters, 1887, in the Tertiary 

 of Xew Zealand. He figured the ovicell well, but did not speak of the oeciostome. 

 It may lie. therefore, that this genus would be more correctly classified in the 

 Tubuliporidae. 



