628 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Affinities. This species differs from ScMzorthosecos interstitia Lea, 1833, in 

 the totally different nature of its inner face, which does not bear very numerous 

 small pores of tubules. 



Bipora eburnea, Mapleston, 1909, is a recent species bearing pores somewhat 

 analogous, but the author has not explained their use. 



Occurrence. Claibornian (Gosport sand) : Claiborne, Alabama (common). 



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



Cotypes.Cat. No. 63863, TT.S.N.M. 



SCHIZORTHOSECOS RADIATUM, new species. 



Plate IS. figs. 1C-19. 



Description. The zoarium is cupuliform. very little concave. The zooecia are 

 indistinct exteriorly, tubular, terminated by a contracted peristomie; before each 



peristomice there are four to 

 six small radial costules; above, 

 in the interzooecial angles there 

 are two small compensation 

 zooeciules or avicularia. The 

 apertura is placed at the base 

 of the peristomie and has a 

 rounded, distal rimule ; the 

 peristomice has also a very wide 

 and quite variable lower inden- 

 tation. On the inner face, the 

 radial series are separated by 

 lateral mural rims, very thick 

 and quite salient; the zooecia 

 appear between them in hexagons, smooth, much elongated, little distinct, ter- 

 minated by an enormous perforation. 



Affinities.- This species is extremely rare; it is very easily confused with the 

 very abundant specimens of the 8chasorth.os.ecos interstitia Lea. 1833. To discover 

 specimens of it one must study under the microscope the inner face of all the 

 specimens found. The enormous salient- collars, as well as the small frontal radia- 

 tions, well characterize this species. 



Occurrence. Claibornian (Gosport sand) : Claiborne, Alabama (rare). 

 Claibornian (Lisbon formation) : Wautubbee Hills, four miles south of Enter- 

 prise, Clarke County, Mississippi (very rare). 

 Cotypes.Cat. No. 63864, U.S.N.M. 



Genus ORBITULIPORA Stoliczka, 1861. 



1861. Orbittili-pora STOLICZKA, Olizocane Bryozoeu von Latdorf in Bernburg Sitzungsber- 

 iflite der k. Akademie der Wissenschaften, Wien, vol. 45, Abth. 1, p. 90. 



The apertura is orbicular. The frontal is a tremocyst. The zoarium is or- 

 bicular and formed of two lamellae with zooecia back to back. 



FIG. 189. Genus Orbitulipora Stoliczka, 1861. 

 A-C. Orbitulipora petiolus Lonsdale, 1850. Natural size 

 and magnified views of a zoarium. (After Reuss, 1867. i 



