836 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Gregory in 1909 distinguished the genera Petalopora and Sparsicavea by their 

 ovicells. Our new observations show no fundamental difference between the 

 ovicells of these two old genera, which appear to be otherwise only zoarial aspects ; 

 we have included them in the genus Parascosoecia. 



Genus ASCOSOECIA Canu, 1919. 



1919. Ascosoecia CANU, Etudes sur les Ovicelles des Bryozoaircs Cyclostoiues (2), Bulletin 

 Societg Geologique de France, ser. 4, vol. 17, p. 347. 



The tubes are cylindrical. The walls of the mesopores are vesicular. 



Genotype. Ascosoecia (Zonopora) ligericnsis D'Orbigny, 1852. 



Range. Xeocomian-Midwayan. 



In this genus it will be necessary to include the forms Zonopora, with bifur- 

 cated mesopores (as Z. Ugeriensis D'Orbigny, 1853) and Multicavea, with peri- 

 stomes arranged in radial rows (as Multicavea magnified. D'Orbigny, 1854). 



ASCOSOECIA PROMINENS. new species. 



Plate 108, figs. 17-2o. 



Description. The zoarium is solid, arborescent, bushy, sometimes reticulat>; 

 and borne on an expanded base. The tubes are cylindrical, bent horizontally at 

 their extremity (in section). The peristomes are thin, orbicular, salient, irregularly 

 arranged in quincunx. The, mesopores are very small and polygonal. The ovicell 

 is globular, very salient, orbicular. 



Diameter of the peristome 0.14-0.16 mm. 



Diameter of the ovicell 1.65 mm. 



Diameter of the branches 2.5 mm. 



This species is quite well characterized by its salient peristomes; but this 

 character is easily lessened on the worn specimens. The number of tubes between 

 the mesopores is irregular. In longitudinal section the mesopores are almost as 

 wide as the tubes ; they appear, on the contrary, much smaller in tangential section. 

 There is probably a thickening of their walls at their extremity. The sections of 

 this species are very difficult to interpret and its structure is still not clearly under- 

 stood. 



Affinities. Ascosoecia promincns differs from Tretocycloecw attenuata Ulrich, 

 1882, in the thinness of the walls of the mesopores. 



Occurrence. Midwayan (Clayton limestone) : Mabelvale, near Little Rock, 

 Arkansas (common). 



Cotypes.Cat. No. 65440, U.S.N.M. 



ASCOSOECIA ? (ZONOPORA) ULRICHI, new species. 



Plate 110, figs. 1-5. 



Description. The zoarium is free, cylindrical, solid, bushy, or reticulate. The 

 tubes are very long, cylindrical, bent at their extremity (in section) . The peristomes 

 are rather thick, nonsalient, grouped in quincunx in irregular, transversal zones. 



Measurements. 



