CORALS AND BRYOZOA. 23 



C(ELOCAULIS, n. S. g. 



Branching forms having the structure of Callopora, but growing as hollow 

 stems, the thin expansion lined with a striated epitheca. 



Callopora (C(elocaulis) venusta. 



PLATE XII, FIGS. 20-24; AND PLATE XXIIl A, FIGS. 1-3,4? 5. 



Callopora venusta. Hall. Twenty-sixth Kept. N. Y. State Mua. Nat. Hist., p. 101. 1874. 

 Thirty-second Rept. N. Y. State Miis. Nat. Hist., p. 155. 1879. 

 Report of State Geologist for 1882. Expl. pi. 12, figs. 20-24. 1883. 



Zoarium ramose, hollow ; diameter of branches from 3 to 5 mm. ; bifurcations 

 frequent. Thickness of tissue from .25 to 1 mm Inner surface a thin epi- 

 theca with transverse wrinkles and fine longitudinal striations caused by the 

 recumbent portions of the cell.s. Cells tubular, arising from the epitheca 

 and parallel with it for a short distance, then turning abruptly outward. 

 Apertures oval, length .33 ram., width .20 mm. ; sometimes irregularly dis- 

 posed, but generally in more or less regular quincunx order ; frequently in 

 contiict : margins thin, except when thickened by silification ; distinctly 

 elevated. Mesopores minute, polygonal ; generally only a single series be- 

 tween adjacent apertures : margins thinner and less elevated than those of 

 the apertures. The margins of the apertures and mesopores are usually 

 smooth, but are sometimes ornamented by numerous minute spinules. Sur- 

 fiice marked by distant, slightly elevated monticules, upon which the aper- 

 tures are larger than on other portions. Intercellular space sometimes 

 septate, at other times apparently vesicular 



This form is distinguished from C. cellulosa by its hollow branches, and its 

 larger and more regularly disposed cells. 



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



Callopora (Ccelocaulis) mediopora, n. sp. 



plate XIV, FIG. 18; AMD PLATE XXIII A, FIGS. 11-18. 



In part CttUopiira paraaitica. Hall. Thirty-second Rept. N. Y. State .Mus. Nat. Hist., p. 157. 1879. 



Report (if State Geologist for 1882. Expl. pi. 14, figs. 13-18. 1883. 



Z0ARIU.M ramose, branches hollow, often flattened ; thickness .75 mm. Cells tubu- 

 lar, oblique to the surface. Cell apertures oval, sub-triangular or trilobate. 



