98 Twenty- SIXTH Report on the State Museum. 



pores, -which open into a series of radiating galleries formed by this 

 covering between the branches ; these galleries also comnmnicate 

 with the interior of the cup by the fenestrules of the inner layer. 

 The cell pores are situated on the branches in the same relative posi- 

 tion as in true rENESTELLA,and open into the galleries, or tubes. The 

 inner portion of these bodies, if denuded of the exterior layer 

 together with a portion of the ridges, would be in every respect like 

 a true Fenestella. 



There is but one species of this type yet known in the Lower Hel- 

 derberg rocks of New York ; and none in any of the older forma- 

 tions ; others occur in the Hamilton group, and several in the 

 precarboniferous rocks of the western States, one of which has been 

 described by Dr. H. A. Prout as Fenestella hemitryjpa^ Trans, 

 Acad. Nat. Sci. St. Louis, Yol. 1, p. 444, pi. 17, f. 4. 



From Fenestella of the ordinary type, there is a somewhat regu- 

 lar gradation, through those with highly elevated intercellular 

 ridges, to the type of Hemitkypa ; and in F. prcecursor^ herein 

 described, we have a form so nearly intermediate that it is difficult 

 to say to which genus it belongs. The highly elevated crests have 

 along their sides a row of small pustules which if prolonged and con- 

 tinued across the spaces would form the characters of Hemitetpa. 



Hemitkypa prima n. sp. 

 Bryozoum forming narrow funnel-shaped bodies, the sides diverg- 

 ing at an angle of from thirty-five to forty-five degrees. Branches 

 slender, round, contiguous, about five in the space of one-tenth of 

 an inch; dissepiments frequent, two-thirds as wide as the branch 

 and expanding at their junction. Fenestrules small, oval or 

 ovate. Bores small, round, with elevated margins, about three to 

 each fenestrule: distance between the inner and outer layers about 

 equal to that between the branches. Outer surface of the cup 

 divided into small rhomboidal openings by small slender filaments 

 connecting the edges of the branches ; usually a little depressed in 

 the middle ; about four to each fenestrule, nine or ten in the length 

 of one-tenth of an inch. 



Formation and locality. — On slabs of the Lower Helderberg 

 limestone, Schoharie, New York. 



Genus ICHTHYOEACHIS McCoy. 



lOHTHTORAOHIS NeREIS n. Sp. 



Bryozoum plumose, slender, slightly flexuose ; midrib flattened 

 on the exterior surface, longitudinally striate, with a groove along 

 the center ; lateral branches short, rigid, obtusely pointed at the 

 extremity, distance from each other equal to the width of the mid- 



