134 THE GENUS MONTICULIPOKA. 



quite, without tabuki;. As the tubes turn outwards towards 

 the surface, as shown in long sections (fig. 22, e), their walls 

 thicken and become fused together; while complete horizontal 

 tabulce are now abundantly developed. There is also seen to 

 be a decided structural distinction between the larger corallites 

 and the interstitial tubes, the latter being much more closely 

 tabulate than the former. Lastly, the thick-walled " spiniform 

 corallites " may be occasionally detected in long sections. 

 Horizon and Locality. — Cincinnati Group, Cincinnati, Ohio. 



Monticulipora (Heterotrypa) suljpulchella, Nicholson. 

 (Fig. 23, and PI. V. figs. 2, 2(7.) 



ChcBtdcs stihpiilchelhis, Nicholson, Pal. Ohio, vol. ii. p. 196, PI. XXI. figs. 6, 6<r, 



1875- 



Spec. Char. — Corallum ramose, of compressed, often greatly 

 flattened branches, which may be quite frondescent, and are 

 commonly partially hollow centrally. An average specimen 

 has a height of over two inches, a width of one Inch, and a 

 thickness of four-tenths of an inch. The ordinary calices are 

 circular or polygonal in form, from i-8oth to i-yoth inch In 

 diameter, with moderately thick walls, and having the apertures 

 of a moderate number of small sub-angular Interstitial corallites 

 interspersed amongst them. These latter, however, are niostly 

 asfSfresfated Into somewhat stellate clusters or maculae, which 

 are not conspicuously elevated above the general surface, and 

 which are placed at Intervals of about one line apart. The 

 larger corallites, which Immediately surround the clusters of 

 small tubes, sometimes appear to be of rather more than the 

 average size. 



As regards internal structure, the corallites are thin- walled 

 In the centre of the branches, but become thickened as they 

 bend outwards, their walls becoming at the same time seem- 

 ingly fused together. Complete horizontal tabulae are devel- 

 oped in all parts of the corallum, but are much more abundant 



