212 THE GENUS MONTICULIPORA. 



Monticulipora (Prasopora) Newberryi, Nicholson. 



(PI. IV. figs, i-i^.) 



Chcztetes Neivberryi^ Nicholson, Palaeontology of Ohio, vol. ii. p. 212, 

 PI. XXII. figs. 4, 4^-, 1875. 



Spec. Char. — Corallum forming thin, sub-circular or semi- 

 circular expansions, which may be from ten lines to an inch or 

 more in diameter, and have a thickness of about i-40th inch. 

 Judging from thin sections, the corallum does not seem to 

 have been parasitic, but to have possessed a thin basal 

 epitheca. Surface exhibiting groups of corallites which are 

 slightly larger than the normal tubes, but which do not form 

 distinctly raised tubercles. Calices thin-walled and polygonal, 

 often apparently without small interstitial apertures, though 

 these can be occasionally detected, and must be generally 

 present. Average diameter of the ordinary corallites about 

 I -70th inch or rather more. As seen in sections, the large 

 corallites are oval, only touching each other at limited points, 

 and having the interspaces between them filled up by numer- 

 ous smaller and irregularly shaped interstitial corallites. The 

 large corallites possess imperfect tabulse, which form a series 

 of convex vesicles on one side of the tube, the other side 

 being open and non-tabulate. Small interstitial corallites 

 with numerous close-set straight tabulae. 



Obs. — My original diagnosis of this species was founded 

 only upon its external characters, and was principally errone- 

 ous in the fact that I had not detected any interstitial tubuli — 

 an error which may be excused, since large parts of the surface, 

 when examined with a lens or with the microscope, really do 

 not show any openings of the smaller corallites. In fact, when 

 thus examined, the surface (PI. IV. fig. ib) is principally notice- 

 able for the polygonal form, the thin walls, and the seemingly 

 close contact of the calices. Nevertheless, thin sections prove 

 conclusively that interstitial tubes are abundantly present ; and 

 the most probable explanation of this apparent discrepancy 



