Corals and Bryozoans of tee Lower Helderberg. 157 

 Callopora parasitica, n. sp. 



(PLATE XIV, FIGS. 13-18.) 



Bryozoum foliate, incrusting or free ; width of largest specimen seen, twenty 

 mm. ; thickness .50 mm. ; cell-tubes at first oblique, but opening directly 

 upward ; apertures comparatively large, nearly oval, very slightly angular, about 

 .20 mm. in length, .15 mm. in width ; cell-margins elevated, frequently spinose 

 at the angles ; distance from each other varying from two to three times their 

 width ; intercellular spaces occupied by polygonal pits, with distinctly elevated 

 margins, in from one to three series ; lower surface covered with an epitheca 

 marked by strong, concentric rugae, and by radiating striae formed by the 

 recumbent portions of the cell-tubes. 



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

 group, near Clarksville, N. Y. 



LICHENALIA, Hall. 



LlCHENALIA TORTA, n. Sp. 

 (PLATE XV, FIGS. 1-7, AND PLATE XIII, FIGS. 17, 18.) 



Bryozoum a thin lamellose expansion, celluliferous on one side ; lower surface 

 covered with an epitheca marked by concentric wrinkles and by fine concentric 

 striae ; cell-tubes comparatively large, radiating from the centre to the margin ; 

 cylindrical, gradually enlarging to the aperture ; recumbent, and nearly parallel 

 with the surface for the greater part of their length ; near the apertures bending 

 quite abruptly upward, and opening slightly oblique to the surface ; length of 

 cell-tubes from one to four mm. ; diameter at aperture nearly .5 mm., arranged 

 in intersecting rows ; intercellular space channeled ; sometimes a slight ridge 

 runs from the anterior portion of one cell to the posterior portion of another. 

 Where the cell-tubes are worn away, the surface is covered by fine, sharp, reg- 

 ular striae, which become slightly nodose in crossing the concentric lines. 

 There are frequent nodes on the surface of well-preserved specimens. 



A specimen showing the cells well preserved is very rarely found, the usual 

 condition being with the cells entirely removed, and showing the concentric and 

 radiating striae. 



This species can be distinguished from L. distans, plate xv, figs. 8, 9, by its 

 larger, circular cell-apertures, and their more regular arrangement. 



Formation and localities. Lower Helderberg group, near Clarksville, and 

 Schoharie, N. Y. 



LlCHENALIA DISTANS, U. Sp. 

 (PLATE XV, FIGS. 8, 9.) 



Bryozoum foliate, incrusting or free ; about .65 mm. in thickness ; cellulif- 

 erous on one side ; lower surface covered by a wrinkled epitheca ; cell-apertures 



