PALEONTOLOGY OF ILLINOIS. - 



ANISOTRYPA Ulrich. Zoaria ramose; branches irregular, hollow, 

 and lined on the inside with an epithecal membrane; or more 

 regular and solid. Zooecia with subcircular apertures. Inter- 

 spaces ridge-like, the comb sometimes with a series of extremely 

 minute granules. Acanthopores and mesopores wanting. 



Type: A. symmetries Ulrich. Range, Keokuk to Chester. 



BYTHOPORA Miller and Dyer. Zoaria consisting of very slen- 

 der ramulets. Zooecial apertures oblique, lanceolate, narrowing 

 above. Interspaces varying in thickness, often channelled. Dia- 

 phragms practically wanting. Mesopores very few or absent. 

 Acanthopores comparatively strong, not numerous, rarely more 

 than one to each zooecium, sometimes w r anting. 



Type: B. fi'uticosa M. and D. Range, Trenton to Lower Hel- 

 derberg. 



CALLOTRYPA Hall. Zoaria ramose, slender, solid. Zooecia small, 

 oval, separated by one or two series of shallow often elongated 

 mesopores. An acanthopore sometimes present at the inferior 

 margin of the aperture. 



Types: C. unispina Hall, and C. multiseriata Hall. Range, 

 Lower Helderberg to Hamilton. The genus will include, beside 

 the two species named, Hall's C. heteropora, and C. oculifera. 



LEIOCLEMA Ulrich. Zoaria ramose, lamellar, sub-globose, or 

 parasitic. Surface frequently exhibiting distinct monticules or 

 maculae. Zooecia with sub-circular or irregularly petaloid aper- 

 tures, separated by abundant angular mesopores, which appear 

 to be open at the surface in the typical species and closed in 

 others. Acanthopores numerous, situated in the walls of the 

 zocecia, strong in the typical forms, (giving the surface a spi- 

 nous character) and very small and inconspicuous in another 

 group of species. Diaphragms few in the zooecial tubes, fairly 

 abundant in the mesopores of the typical section, crowded in 

 the majority of the species now provisionally referred to the 

 genus. 



Type: Callopora punctata Hall. Range, Cincinnati to Chester. 



Family AMPLEXOPORIDJS n. fam. 



Zoaria ramose, incrusting, discoidal, or massive, rarely bi- 

 foliate. Zooecia comparatively simple, prismatic, with a well 



