SECONDARY AND TERTIARY FORMATIONS OF NORTH AMERICA. 173 



RETICULIPORA. 



Colony composed of branches, often much compressed, usually anastomosing. Cel- 

 lules placed on the top and sides, " opposed pore " at the back. Cellules arranged in 

 more or less regular transverse lines, no accessory pores. 



Increase taking place from the extremity and on the sides of the branches. A 

 median germinal plate running along the middle of the branches. 



The absence of accessory pores distinguishes this genus from Bicrisina, the only 

 nearly related form. 



R. sagena, G. and H., Proc. Acad. Nat. Sci. Philada., 1860, p. 366. Id., Journal 

 Acad., vol. 4, p. 400, pi. 69, fig. 30, 31, 32. 



Colony composed of broad branches, anastomosing irregularly. Branches, with the 

 sides parellel or a little the widest at the top. Cellules crowded, large, subangular, 

 dividing walls thick. Germinal plate distinct, but not prominent, surface adjoining 

 it often rounded. 



One specimen only is known to us. It is from Timber Creek, N. J., Cretaceous and 

 is imbedded in such a hard matrix that we are unable to see all the characters in as 

 satisfactory a manner as we could desire. 



It resembles in its mode of growth, It. Ligeriensis, but differs in the cellules being 

 crowded on all parts of the specimen, as far as we can uncover it. 



R. dichotoma, n. s., fig. 64. — Colony branched, probably not anastomosing. Branches 

 sharp above, widening below, widest at or near the back, which is rounded. Cellules 

 crowded near the upper edge, placed with an irregular transverse arrangement, scat- 

 tered posteriorly. When the cellules are not crowded they are often bordered by a 

 raised lip posteriorly. The back of the colony is pierced by a few scattered pores, 

 some of which are bordered by a faint rim. Germinal plate thin, distinct, prominent 

 at the upper margin, and visible in the section, almost as far down as the back of the 

 branch. 



One specimen only, from Timber Creek, N. J. Cretaceous. 



The prominent germinal plate, narrow branch, probable absence of anastomosis and 

 the shape of the transverse section of the branch, which is widest above, or at 

 least parallel, in R. sagena, sufficiently prove this to be a distinct species. 



We have another species, represented by two or three compressed, almost cylindri- 

 cal branches, from the deposit near Mullica Hill, but they are too imperfect for des- 

 cription. 



BICRISINA. d'Orb. 



Colony testaceous, composed of rounded, compressed or subquadrate branches. 

 Cellules arranged in transverse lines on the sides and lateral portions of the top of the 



