82 



BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



surface directly, from 0.2 to 0.3 mm. in diameter, about 6 in 2 mm. 

 Numerous small mesopores are present among the zooecia and usually 

 isolate them. Lunarium narrow but prominent, occupying one- 

 fourth to one-third of the wall's circumference. Thin sections show 

 the usual laminated wall tissue of the Ceramoporidse. The granules 

 or acanthopore-hke structures are most pronounced in tangential 

 sections. 



Fig. 22.— Ceeamoporella GRANrn-osA minok. a, tangential section, X20, showing few geanxtles 



AND general arrangement OF ZOCECIA AND MESOPORES; 6, VERTICAL SECTION, X20, THROUGH A SINGLE 

 LATER OF ZOCECLA. JEWE LIMESTONE (Dl), BARON TOLL'S ESTATE, ESTHONLA.. 



Occurrence. — The new variety minor is described from specimens 

 occurring in the Jewe limestone (Dl), Baron Toll's estate, near Jewe. 

 It is also known from the Wassalem beds (D3) at Uxnorm, Esthonia, 

 and from the Black River (Decorah) shales of Mmnesota. 



Holotype.— Cat. No. 57192, U.S.N.M. 



The collections of the British Museum contain a specimen from the 

 Jewe limestone. Baron Toll's estate. 



CERAMOPORELLA UXNORMENSIS, new species. 

 Text fig. 23. 



Zoarium incrusting, forming expansions several millimeters thick 

 and as many centimeters in width. Surface smooth but with clusters 

 of larger zooecia from which the ordinary ones radiate. Zooecia with 

 moderately thick walls; apertures subrhomboidal to irregularly polyg- 

 onal, obhque on account of the small but distinct overarching 

 lunarium. Zooecia arranged in rather regular radiating series about 

 the maculse; five zooecia in 2 mm. Mesopores few, often entirely 

 absent. 



The most conspicuous feature of thin sections is the unusual thick- 

 ness and distinctness of the limariiun, characters which are not so well 

 showTi at the surface. In vertical sections the zocecial tubes are 

 prostrate and thin-walled in the axial region, but thicken and show the 

 characteristic laminated wall structure in the peripheral zone. Both 

 regions are without diaphragms. 



Although closely alhed to several American Ordovician species, 

 such as Ceramoporella ohioensis (Nicholson) and C. whitei (James), the 



