Palceozoic Corals of the State of Ohio. 91 



species, in long sections, by the wide straight corallites, which 

 are furnished with regular remote tabulae, and which have 

 small, more closely tabulate tubuli occasionally intercalated 

 amongst them. In cross sections (PI. V. fig. 14) the corallites 

 are seen cut longitudinally around the margin and transversely 

 divided in the centre, where they are polygonal and thin- 

 walled. 



Chcetetes tuberculatus, Edwards & Haime. 

 Chcetetes corticans, Nich. op. cit. p. 210, pi. 22, figs. 6, 6 a. 



There can be no doubt that the form to which I gave the 

 name of C. corticans is really identical with the C. tuberculatus 

 of Edwards and Haime. I have not yet had the opportunity 

 of making sections of this species, and am therefore unable 

 to give any details as to its internal structure. 



Chcetetes clatliratuluSj James. 

 Cheetetes clathratulus, Nich. op. cit. p. 209, pi. 22. figs, 2, 2 b. 

 It seems not unlikely that this is really the Chcetetes {Pttlo' 

 dictya) pavonia of D'Orbigny ; but the published figures of 

 the latter species do not allow of a satisfactory determination 

 of this point. Be this as it may, the internal structure of 

 C. clathratulus is highly characteristic and peculiar. In tan- 

 gential sections taken parallel with the surface (PI. V. fig. 9), 

 the corallites are seen in the form of oval tubes, an-anged in 

 two series of regularly decussating diagonals, each tube being 

 directed with its long axis oblique to the row to which it 

 belongs. The walls of the corallites are very thick, and no 

 interstitial tubuli are present. Each corallite seems to be 

 primitively more or less hexagonal or diamond-shaped; and 

 the oval section of the interior of the tube is clearly due to a 

 secondary thickening of the walls. In long section (PI. V. 

 fig. 9 a) the corallum is seen to consist of two strata of coral- 

 lites directed outwards in opposite directions from a delicate, 

 flexuous, median lamina, with which their waUs are sometimes 

 connected by thin plates. Sometimes (as in the figure) a 

 second stratum of short corallites may be superimposed upon 

 one of the original layers. The walls of the corallites are very 

 thick ; and tabulse appear to be wholly absent. This latter 

 feature leaves it still doubtful if this singular form can really 

 be referred to Chcetetes. 



Chcetetes frondosus^ D'Orbigny. 

 Cheetetes frondosus?, Nich. op. cit. p. 208, pi, 22. figs, 1, 1 6, 

 I am still in doubt whether my specimens are really refer- 



