370 Observations upon Stenopora fibrosa, etc. 



by the successive addition of lateral or marginal tubes." It is quite 

 true that it does increase in one of these ways, and it is equally true 

 that it does not in the other. In other words, it does increase by 

 lateral tubes, either interpolated or marginal, but it does not increase 

 by subdivisions of the parent tube. Its method of growth was simply 

 gemmiparous, and therefore it belongs to the genus Stenopora, and not 

 to Chetetes. 



It includes all the massive forms found at the Cincinnati quarries, 

 some of which weigh five pounds or more, and is regarded by McCoy 

 as merely a variety of Stenopora fibrosa. 



All the numerous forms of branching and massive corals found at 

 Cincinnati, which are composed of masses of aggregated tubes, crossed 

 by diaphi-agms, belong to these two species. 



The following remarks concerning the genus Chetetes, by W. Lonsdale, 

 are taken from his work on the paleozoic corals of Russia, as published 

 in vol. 1, p. 593, of "Russia and the Ural Mountains." 



Chetetes — (Fischer). 



So greatly do the corals referable to this genus resemble Favosites 

 (Calamopora) that all the authorities, except M. Fischer, by whom paleo- 

 zoic species have been described, have considered them as belonging 

 to it. M. Fischer, in his summary of characters, observes, that Chcetetes 

 is distinguished from Favosites {Calamopora) by the absence in the 

 tubes of "diaphragms" or transverse laminse. This statement prob- 

 ably originated from an examination of specimens of CJietetes radiants, 

 in which species the diaphragms are often very widely separated, and 

 not unfrequently have been almost altogether removed by decomposi- 

 tion. In this respect, therefore, Chetetes does not differ from Favosites ; 

 but it differs in the absence of connecting foramina as well as in other 

 essential structural characters. 



When a specimen of Favosites, retaining in part the substance of 

 the original coral, is vertically fractured, the walls of the adjacent col- 

 umns separate readily, and the exposed surfaces are clearly shown to 

 present the outer side, by exhibiting the irregular lines of growth, and 

 by the total absence of any attached fractured edges of diaphragms. 

 At the re-entering angles, formed by the meeting of the planes of two 

 a^Jjacent columns, there may likewise be generally traced an undis- 

 turbed line -of separation. In those cases in Avhich mineral matter 

 has wholly replaced the original substance of the coi'al, and has also 

 been moulded on its structural markings, the same tendency to divide 



