534 Report of the State Geologist. 



In the triangular branches they proceed from laminae, which 

 extend from the center to each angle of the branch ; in the flat- 

 tened branches they proceed from the mesotheca, and are recum- 

 bent for about one-half their length, then abruptly turning and 

 generally opening directly outward ; intercellular tissue vesicular . 

 cell apertures disposed in parallel longitudinal rows, and frequently 

 in oblique ascending rows from the middle of the branch ; 

 apertures of the central rows the smallest, gradually enlarging 

 to the marginal rows. 



There is usually a prominent carina along the middle of the 

 flattened branches. 



Family Intraporidae, nov. fam. 



The forms included in this family have essentially the same 

 manner of growth as the Stictoporidse, but differ from the mem- 

 bers of that family in having the interapertural space occupied 

 by the cavities of vesicles. 



The following genera are included in the family ; CosoiiJELLi, 

 Intbapoea., Semiopoba and Stiotoporella. 



Cosoinella, Hall. 

 (Pal. N. r., Yol. Yl, p. 19, pi. 64, figs. 9-12. 1887.) 



Type, GosGinella elegantula^ Hall. 



(Plate 14, figs. 7-12.) 



Zoarium consisting of an explanate frond, celluliferous on each' 

 face, with perforations or f enestrules at somewhat regular distances 

 from each other ; the whole having the appearance of being com- 

 posed of sinuous anastomosing branches ; base spreading, adher- 

 ing to cyathophylloid corals or other bodies; mesotheca very 

 thin, marked by arching undulations of growth, and also by 

 longitudinal striations caused by the recumbent portions of the 

 cell tubes ; cells tubular, cylindrical ; for one-half their length 

 resting upon the mesotheca, then abruptly bending and continu- 

 ing at right angles to their former course, opening directly out- 

 ward; intercellular tissue composed of minute tubuli, with very 

 closely disposed septa, or of vesicles so disposed that they have 

 the appearance of septate tubuli; cell apertures circular; closely 

 and irregularly disposed. The interapertural surface, and a space 

 about .75 mm. wide around each fenestrule are occupied by 

 minute angular pits. 



