American Palaeozoic Bryozoa. 



lib 



forms a small "lip." Cell-interspaces of variable thickness, smooth 

 when worn, and minutely pitted or granular when well preserved; nine 

 or ten cells occupy the space of .1 inch. At intervals of usually less 

 than .2 inch are developed distinct " maculae,'' which are either mi- 

 nutely pitted or striated, and generally even with the surface. In one 

 specimen they are prominently elevated. 



In tangential sections taken just below the surface, the tubes are sub- 

 circular, with a thin, but disinct ring-like wall. The interstitial spaces 

 are occupied by minute dots (? spiniform tubuli), and have a thick- 

 ness often equaling the diameter of the tubes. 



In longitudinal sections, the tubes proceed from the median axis 

 to the surface very obliquely, and in a long and gradual curve. A 

 line drawn from the aperture to the point at which a tube is 

 developed, forms an angle of about 35° with the central axis. 

 As the tubes approach the surface, they are slightly contracted in 

 their diameter, and the interstitial spaces expand rapidly, until, 

 near the surface, the} T have a thickness equal to the diameter of a tube; 

 these spaces are occupied by nearly structureless sclerenchyma, which 

 (when they are preserved) are vertically traversed by rather indis- 

 tinct dark streaks. The tubes are crossed by remote diaphragms. 



Another species of this genus occurs quite abundantly at High 

 Bridge, Kentucky, where it is associated with P. frondosa, from which 

 it differs mainly in external features. 



Formation and locality: In middle Trenton strata, at High Bridge, 

 Kentucky, and other localities in that vicinity. 



[To be Continued.] 



DESCRIPTIONS OF TWO NEW SPECIES OF CR1NOIDS. 



By E. O. Ulrich. 



Heterocrinus (Iocrinus) cehanus, n. sp. (PI. V., figs. 9, 9a, 96.) 



Body small, obconic, pentalobate, and gradually expanding upward 

 from the column. Basal pieces pentagonal, about as high as wide. In 

 over twenty specimens examined, the sutures between the body plates 

 can scarcely be detected. As well as could be determined, their ar- 

 rangement is as follows: First radial, in all the rays excepting the 

 right posterior one, about as long as wide, and supporting in succes- 

 sion two shorter and smaller pieces which belong to the body. In the 

 right posterior ray, the first radial is wider than long, and succeeded 

 by a shorter pentagonal piece, which supports upon its superior sloping- 

 aces the next succeeding smaller radial, and the large irregularly 



