American Palaeozoic Bryozoa. 



257 



son, the former from the Cincinnati Group, the latter from British 

 Lower Silurian deposits. 



The genus Petigopora is founded upon an, as yet, undescribed 

 species. It, however, includes Chaitetes petechialis, Nicholson. 



Dekayella is also founded upon a new species, but M. ulrichi, 

 Nicholson, is a congeneric species. Several undescribed species are 

 known to me. 



The type species of Discotrypa, is the form described b}^ me in the 

 second volume of this Journal, under the name of Chaitetes elegans. 



Stellipora antheloidea, Hall, is restricted to the Trenton Group of 

 New York, and is not by any means the same as the Cincinnati Group 

 species usually identified with it. The zoarium of the former is thin 

 and incrusting, while that of the latter grows upward into branches or 

 narrow fronds. As it has never received a distinct name, I here pro- 

 pose that it be called Constellaria Jlorida. It may be briefly charac- 

 terized as follows : 



Constellaria Florida, n. sp. 



Zoarium ramose or subfrondescent, from one to two tenths of an 

 inch in thickness, and from one to three inches in height. Surface 

 with numerous areas, which typically are stellate, about .08 inch in 

 diameter, and placed at intervals of about .12 inch (measuring from 

 center to center) and are usually arranged in transverse rows. Each 

 consists of a depressed central space, surrounded by from five to nine 

 prominent and radially arranged elevated ridges. Often these areas 

 coalesce and form transverse ridges, that not infrequently are continu- 

 ous around the branches.- Cells of two kinds, differing in size and 

 other features. The proper zooecia are oval or circular, and on an 

 average about twelve occupy the space of .1 inch. Their apertures are 

 surrounded by a small but distinct rim. The central depressed areas 

 of the stellate monticules are composed entirely of the interstitial cells, 

 which occupy also all the interstices between the proper circuiar cells. 



As I find myself unable to do justice to the complicated internal 

 characters of the species, without the aid of figures, I beg leave to re- 

 serve this portion of the description, until, in the course of my memoir, 

 Stellipora and Constellaria come up for consideration. For the 

 identification of the species, a knowledge of its internal structure is 

 not, at the present time necessary, since C. Jlorida is one of the most 

 characteristic and common fossils of the Cincinnati Group. 



The genus Cheiloporella is founded upon Fistulipora Jlabellata, 

 described by me in the second volume of this Journal. 



Crepipora is founded upon a new species. Chaitetes venustus, 

 Ulrich, will be referred to the genus. 



[to be continued.] 



