416 PALEONTOLOGY OF ILLINOIS. 



DEKAYIA DEVONICA Ulrich. 



PI. XLV, flg. 5-5d. 



Zoarium ramose, consisting of small subcylindrical irregular 

 branches, averaging six or seven mm. in thickness; in one in- 

 stance solid, in all the others hollow with a AA r rinkled epitheca 

 lining the interior; in the latter the zoarium has a thickness of 

 less than 1 mm. Surface level or with slightly elevated clusters 

 of larger apertures and bristling with very prominent spines 1 

 mm. or a little less apart. Zooecia angular, quite oblique to 

 the surface, thin-walled throughout, about five in two mm., 

 measuring longitudinally, with elongated, unequal apertures. 

 Diaphragms few, one, or perhaps more to a tube. Acanthopores 

 exceedingly prominent, with very thick walls. 



The examples from New York are hollow and appear to be 

 composed of one or more very thin layers. The specimen from 

 the Ohio Falls has a solid axis. The extreme obliquity of the 

 zooecial tubes and the very strong acanthopores distinguish this 

 form from any Devonian bryozoan known to me. 



Position and locality: Devonian; Falls of the Ohio; Eighteen 

 Mile Creek, N. Y. (Hamilton group). 



CALLOPORA Hall, 1852. 



(Pal. N. T. vol. H, p. 144.) 

 (For generic diagnosis, see page 372.) 



This is a distinct and easily recognized genus, and so far as 

 known, its range does not extend into Devonian deposits, but 

 in all the groups of rocks between the Trenton limestone and 

 the Lower Helderberg, inclusive, it is represented by from one 

 to twelve species. In all, twenty species have been studied, but 

 only thirteen of them are described. The first species to follow 

 Hall's generic description is his C. elegantula, from the Niagara 

 group afc Lockport, N. Y. According to commonly accepted 

 rules of nomenclature, the species must stand as the type of 

 the genus. Of the remaining species which Hall described and 

 referred to the genus in 1852, C. aspera and probably C. floridn 

 and C. lammata belong to Leioclema as now understood; while 

 C. nummiformis is very likely referable to Calloporella. With 



