440 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



SCHIZEMIELLA CLAIBORNICA Canu and Bassler, 1917. 

 Plate 14, figs. 2-4. 



1917. Schisemiella claibornica CANU and BASSLER, Synopsis American Early Tertiary 

 Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 47, pi. 4, fig. 9. 



Description. The zoarium is free, bilamellar, with inseparable lamellae. The 

 zooecia are indistinct; the frontal is thickened, little convex, formed of a tremocyst 

 with large, irregular tubules placed on a thin olocyst with very small pores in 

 quincunx. The apertura is formed of an ogival anter and a concave poster with 

 a very wide rimule; the peristomice is elongated, embedded, with a very wide, 

 irregular rhnule-spiramen. The ovicell is hyperstomial and opens largely into the 

 peristomie; it is little globular, hardly salient; covered by a smooth or perforated, 

 very fragile wall; the peristomice is elliptical and transverse. The avicularium is 

 triangular, the point directed above, adjacent to the peristomice which it deforms, 

 provided with a pivot. 



Measurements. Peristomice ihpe=0.20 mm. Apertura [7)a=0.12 mm. 



(exterior) l?/?e=0.14-0.16 mm. (interior) IZa=0.11 mm. 



ZooecialZs=0.54 mm. 

 (interior) 113=0.30 mm. 



Variations. In the interior the tremopores are regularly placed in quincunx ; 

 on the exterior they are very irregularly disposed, larger and less numerous. 



The frontal of the ovicell is so fragile that we are unable to get an exact idea 

 of it from our few specimens. This organ requires further examination. 



The rimule of the peristomice is very irregular. In reality the form of the 

 apertura belongs (fig. 4) to the group of very typical ScMzoporella, and the oper- 

 culum ought to be chitinized enough to sufficiently insure the opening of the com- 

 pensatrix by itself. 



Occurrence. Claibornian (Gosport sand) : Claiborne, Alabama (rare) ; 1 mile 

 southwest of Rockville, Clarke County, Alabama (rare) ; Gopher Hill. Tombigbee 

 River, Alabama (rare). 



Claibornian (Cook Mountain formation) : Moseleys Ferry. Caldwell County. 

 Texas (rare). 



Cotypes.CvA,. No. 62595, U.S.N.M. 



Genus METRADOLIUM Canu and Bassler, 1917. 



1917. Metradolium CANU and BASSI.EK, Synopsis American Early Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. 47. 



The ovicelled zooecia, different in form from the others, have a peristomice 

 in the form of a lunar crescent without rimule-spiramen. The frontal is a tremo- 

 cyst with tubules. 



Genotype. Metradolium dissimile Canu and Bassler. 1917. Jacksonian. 



Eschara tiiberosa Reuss. 1866, of the Stampian of Germany, belongs without 

 doubt to this genus. 



