EAEliY PALEOZOIC BEYOZOA OP I'HE BALTIC PEOVINCES. 



83 



present form may be distinguished by its unusually thick and dis- 

 tinct lunarium. The type-specimen is in such condition that the 

 surface could not be figured, but by slight etching, such a view as 

 shown in figure 23a is obtained. 



Fig. 23.— Ceeamoporella uxnokmensis. a and &, tangential section, x20 and X35, illustrating 



THE SHAPE OF ZOCECIA AND THE THICK LUNAKIUM; C, VERTICAL SECTION, X20. WASSALEM BEDS (D3), 

 UXNORM, ESTHONIA. 



Occurrence. — Apparently rare in the Wassalem beds (D3) at 

 Uxnorm, Esthonia. 



H olotype.— Csit. No. 57194, U.S.N.M. 



Thin sections of the type-specimen are in the collections of the 

 British Museum. 



Genus CCELOCLEMA Ulrieh. 



Cceloclema Ulrich, Journ. Cincinnati Soc. Nat Hist., vol. 5, 1882, p. 137; vol. 7, 

 1884, p. 49.— NiCKLES and Bassler, Bull. 173, U. S. Geol. Surv., 1900, pp. 24, 

 211.— Bassler, Bull. 292, U. S. Geol. Surv., 1906, p. 21.— Cumings, Thirty- 

 second Ann. Rep. Dep. Geol. Nat. Res. Indiana, 1907, p. 742. 



Diamesopora (part) Ulrich, Geol. Surv. Illinois, vol. 8, 1890, pp. 380, 467; Geol. 

 Nat. Hist. Surv. Minnesota, vol. 3, pt. 1, 1893, p. 330. 



Diamesopora Ulrich, Zittel's Textbook of Paleontology (Eng. ed.), 1896, p. 268. 



Zooecia very much as in Ceramoporella but differing in forming a 

 zoarium of ramose, hollow branches lined internally mth a striated 

 epitheca. 



Genotype. — Diamesopora vaupeli Ulrich. Upper Ordovician (Eden) 

 of the Oliio Valley. 



This genus is readily distinguished from related members of the 

 Ceramoporidge by its zoarial characters. Five species have been 

 described from the American Ordovician and Silurian deposits, while 

 at least three new forms await description. The following new 

 species is closely related to one of the undescribed American Middle 

 Ordovician forms, but differs from this as well as all other species of 

 the genus in its larger zocecia and unusually thick walls. 



