172 



BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



grano-lineate ornament of the noncelluliferous side. The other 

 Russian species of the genus are too different to require comparison, 

 but in America certain undescribed Black River forms are closely 

 selated. As shown on plate 12, the zoarium is a fiabelliform expan- 

 tion consisting of slender inosculating branches averaging 0.3 mm. 



in width. The f enestrules 

 are large and elongate, 

 generally two or three 

 times longer than wide. 

 Measuring lengthwise, 

 four fenestrules occur in 

 1 centimeter. 



Occurrence. — Eich- 

 wald's types were ob- 

 tained from ''le schiste 

 inflammable argileux" at 

 Erras. The species is 

 quite abundant in the 

 Kuckers shale (C2) , Baron 

 Toll's estate, near Jewe, 

 Esthonia. 



Plesiotype. — Cat. No. 



Fig. 87.— Chasmatopoea fuecata. Eichwald's vie-ws of 57264 XJ.S.N.M. 



POLTPORA FTmCATA. O, ZOAEIUM, NATUEAl SIZE; 6, AN _,, n ,• (• , i 



Ihe collections or the 

 British Museum contain 

 specimens and thin sec- 

 tions from the Kuckers shale (C2), Baron Toll's estate. 



ENLARGEMENT OF THE NONPOEIFEROUS SIDE, SHOWING DIS- 

 TINCT EO"WS OF papilla; C, CELLtTLrFEROUS FACE ENLAEGED. 

 "ScmSTE INFLAMMABLE AEGILETJX," EEEAS, ESTHONIA. 



Genus PSEUDOHORNERA Roemer. 



Pseudohornera Roemer, Letli. geog., Leth Pal., vol. 1, Atlas, 1876, expl. pi. 



12.— Bassler, Bull. 292, U. S. Geol. Surv., 1906, p. 49. 

 Drymotrypa Ulrich, Geol. Surv. Illinois, vol. 8, 1890, p. 309. — ^Miller, North. 



Amer. Geol. and Pal., First Appendix, 1892, p. 684. — Nickles and Bassler, 



Bull. 173, U. S. Geol. Surv., 1900, p. 235. 

 Thamnocdla Simpson, Fourteenth Ann. Rep. State Geol. New York for 1894, 



1897, p. 525. 



This genus is best known under the name of Drymotrypa, to which 

 practically all of its species have been referred, but Pseudohornera 

 must be retained since it, as well as Drymotrypa, was founded upon 

 the same species. Hall's Retepora diffusa. 



The zoarium m. Pseudohornera is of dichotomously dividing branches 

 celluliferous on one side and longitudinally striated on the reverse. 

 The zooecia are in several ranges and spring from a thin double plate, 

 beneath which is a number of vesicles; the vestibules expand from 

 the orifice to the angular apertures. 



Genotype. — Retepora diffusa Hall. Niagaran of New York and 

 Canada. 



