26 AMERICAN FOSSIL BRYOZOA. [bull. 173. 



interspaces wide, occupied by a single series of large angular meso- 

 pores with numerous diaphragms and never presenting the appearance 

 of vesicular tissue; apertures subcircular, with a well-developed gran- 

 ose peristome, but no lunarium. 



Genotype: Flstulip<yra degata^ Rominger. Devonian, 



Chilotrypa Ulrich. 



Zoarium small, ramose, with a narrow, irregularly contracting and 

 expanding axial tube; diaphragms few or absent; apertures elliptical, 

 oblique, the lower margin thickened and elevated; interstitial vesicles 

 connnonly filled b}' a dense calcareous deposit near the surface. 



Genotype: CMlotrypa Idspida Ulrich. Range, Silurian-Mississip- 

 pian. Plight described and five new species. 



Strotopora Ulrich, 



Zoarium ramose, with irregular branches. Like Fistulipora, but 

 the surface presents distril^uted among the apertures large, abruptly 

 spreading cells (regarded as broken ovicells); when perfectly preserved 

 these appear as strongly convex elevations with a small opening on oi e 

 side. 



Genotype: Strotopora foveolata Ulrich. Devonian, Mississippian. 

 Three species. 



Meekopora Ulrich. 



Zoarium l)ifoliate, sometimes branching; the mesotheca thin and 

 flexuous; zooecia tubular, proceeding in a gentle curve from the meso- 

 theca and opening somewhat obliquely upon the surface and provided 

 with numerous, often recurved, diaphragms; apertures oblique, all 

 pointing distally; lunarium, when present, not verj' prominent; rather 

 large ovicells developed, showing at the surface as a convex space with 

 a small apical opening. 



Genotype: Meekopora exmviaXWxxQh. Range, Silurian-Carboniferous, 

 Six described and three new species. 



LiCHENOTRYPA Ulrich. 



Zoarium thin, incrusting; in its first stages like Fistulipora; as it 

 matures, large spines and thin walls are thrown up about the aper- 

 tures; numerous subangular vesicular openings interspersed among 

 the apertures and scarcely distinguishable from them. 



Genotype and only known species: Lichenotrypa cavernosa Ulrich = 

 Licheiialla longispina Hall. Devonian. 



BusKOPORA Ulrich (Odontotrypa Hall). 



Like Fistulipora, but lunarium remarkably developed, projecting as 

 a strong, bidenticulate process nearly half way across the aperture. 

 Genotype: Buskoporadentata\}\x\Q\\. Devonian, Four species. 



