BRYOZOA. 375 



Type: S. antheloidea Hall, from the Trenton limestone. 



IDIOTKYPA Ulrieh. Zoaria parasitic. Zooecia sub-circular, with 

 a faint peristome, separated from each other by a series of 

 large irregular closed mesopores,. Zooecia and mesopores not 

 distinguishable in vertical sections, both being crossed by thick 

 parallel diaphragms, occurring at short and regular intervals. 

 Diaphragms apparently perforated by numerous minute fora- 

 mina. Walls with numerous minute vertical tubuli or cells. 



Type: /. parasitica Ulrich. Trenton and Niagara. 



Family BATOSTOMELLID.E n. fam. 



Zoaria multiform, often consisting of superimposed layers; 

 never bifoliate. Zooecia with thick walls in the mature region, 

 where they usually appear fused together. Diaphragms hori- 

 zontal, those in the peripheral region centrally perforated, 

 originally functioning as covers to the cell apertures. Meso- 

 pores usually present, often intermittent, generally without dia- 

 phragms and distinct walls; when abundant they are small. 

 Acanthopores well developed. 



BATOSTOMELLA Ulrich. Ramose, branches slender, without 

 monticules. Zooecia thick-walled in the peripheral region, inter- 

 sected by remote, delicate, originally perforated diaphragms. 

 Apertures small, circular or oval. Interspaces rounded, thick, 

 spinulose: the acanthopores small and usually very numerous. 

 Mesopores subcircular, small, varying in number. 



Types: B. spinulosa n. sp., and B. gracilis Nicholson. Tren- 

 ton to Coal Measures. 



STENOPOKA Lonsdale. Zoarium ramose, sublobate, massive, 

 laminar or parasitic. Surface even or montiferous. In the 

 mature region the zooecial tube walls are periodically thickened 

 so as to appear moniliform in vertical sections. Comparatively 

 large acanthopores are developed at the angles of the cells. 

 Diaphragms straight, more or less numerous, with a large cen- 

 tral perforation; a few irregular mesopores occasionally present. 



Type: S. tfMiifinieiifiifi Lonsdale. Ranges through the Car- 

 boniferous svstem. 



