610 Report of the State Geologist. 



ISOTRTPA, Hall. 



(Report of N. Y. State Geologist for 188i, p. 37. 1885.) 



Type, Isotryjpa conjunctiva, Hall. 



(Plate 6, figs. 7-12.) 



Bryozoum having the same general appearance as Fenestella; 

 cell apertures arranged in two parallel rows separated by a 

 carina; carinas prominent, expanded at the summit ; summits 

 connected by round or oval, comparatively distant lateral bars. 

 On the noncelluliferous face a conspicuous pore occurs on or near 

 each dissepiment. 



This genus differs from Unitrtpa not only in having con- 

 spicuous pores on the noncelluliferous face, but also in the char- 

 acter of the lateral processes. In Unitrypa the scalse consist of 

 thin, oblique or bent, imbricating plates, which usually extend 

 on the sides of the carinae for at least one-half their height, each 

 scala being formed of two lamellae, coalescing at the summit. 

 The carinae of this genus are not of equal thickness, and when 

 broken the base of the thicker portion alone remains attached to 

 the branches, closely resembling a row of elongate nodes, in this 

 respect being similar to Hemitbtpa. 



Fig. 59. Isotrypa eoixjunctiva. A side view of a portion of a branch and Itsoarlnee ; also showing a 

 section of the dissepiments and scalee, xl8. 



Tectdliporella, Simpson. 

 (Ann. Rept. of K Y. State Geologist for 1893.) 

 Type, Tectuliporella consimilis, Hall. 



(Plate 6, figs, 13-15.) 

 This genus resembles Isotrypa in general appearance and man- 

 ner of growth, but the summits of the carinae and connecting 

 bars are much stronger and are scarcely distinguishable from the 

 noncelluliferous face of the frond. It differs, also, from Isotrypa 

 in being without pores on the noncelluliferous face of the frond, 

 and on the sides of the carinae, above the cell apertures. 



