Corals and Bryozoaxs of the Lower Held krb erg. 151 

 Trematopora regularis. 



(Plate xi, figs. 1-8, and plate xiii, figs. 1-3.) 



TVematopora regularis, Hall. Twenty-sixth Rep. N. Y. Stale Mas. Nat. Hist., 



p. 106. 1874. 



Bryozoum ramose, solid, slender; branches frequent, widely diverging; 

 diameter of larger branches about one mm. ; cell-apertures elongate oval, 

 arranged in longitudinal, parallel lines, alternating, forming a quincunx arrange- 

 ment ; about eighteen in the space of five' mm. longitudinally ; generally five 

 rows in the width of a branch, sometimes a short spine at the lower end of 

 the cell-aperture ; space between the rows of apertures frequently elevated into 

 a ridge, which in well-preserved specimens has a serrated crest. 



This species is easily distinguished by its slender branches and the arrange- 

 ment of cell-apertures in parallel longitudinal rows, separated by an elevated 

 ridge. 



Formation and locality. In the shaly limestones of the Lower Helderberg 

 group, near Clarksville, N. Y. 



Trematopora ovatipora, n. sp. 



(PLATE XI, FIGS. 9, 10.) 



Bryozoum ramose, solid, slender ; diameter of the branch about one mm. ; 

 cell-apertures ovate, about twice as long as wide, arranged in parallel, longi- 

 tudinal rows; eight cells in the space of five mm. longitudinally; three rows 

 in the width of a branch ; a short spine at the base of each cell ; margins 

 slightly elevated, granulose. 



This species can be distinguished from T. regularis by its much larger ovate 

 cells and coarser appearance generally. 



Formation and locality. Lower Helderberg group, hear Clarksville, N. Y. 



Trematopora canaliculata, n. sp, 



(PLATE XI, FIG. 12.) 



Bryozoum ramose, solid; diameter one mm.; cell-apertures comparatively 

 large, oval, distant ; length about .20, and width .10 mm. ; arranged in quincunx 

 order; space between cell-apertures channeled, leaving their margins elevated. 

 Always on the margin at the ends of the aperture, and frequently on other parts 

 of the margin, there is a short, obtuse spine. 



This species, in its arrangement of cell-apertures, is very similar to T. rhom- 

 bifera, but differs from that species by having the cell-apertures much more 

 distinctly oval, and more widely separated, the space between the cell-apertures 

 being channeled. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 



