On the Genus Monticulipora. 



25 



NOTICE OF A WORK BY PROF. NICHOLSON ON THE 



GENUS MONTICULIPORA. 



By S. A. Miller, Esq. 



In 1874, the writer said, that " after the most careful examination 

 of hundreds of specimens,, polished and unpolished, fractured and 

 weather-worn, under the most favorable circumstances, the fact that no 

 coral possessing the generic characters of Chetetes was ever found within 

 the Cincinnati Group, seems too clearl}' - established to leave a remnant of 

 doubt upon the subject." That in Chetetes "it is a generic characteristic 

 that the walls of the tubes are inseparably connected together, owing 

 to the fissiparous method of reproduction, while the walls of the 

 corals from this locality readily separate."* 



Prof. Nicholson found it impossible to separate Monticulipora 

 from Chetetes, \ and consequently referred our corals to the latter 

 genus. This view he continued to entertain until a comparatively 

 recent date, when he changed his mind, and referred them to the 

 former genus, though it can not be said that very much new light had 

 been thrown upon the subject since the work of Edwards & Haime, 

 published nearly twenty } r ears ago. The late work by Prof. Nicholson, 

 "On the Structure and Affinities of the. Genus Monticulipora, and its 

 subgenera," is almost entirely devoted to the corals of this locality, and 

 hence contains a revision of the work done in the " Ohio Palaeon- 

 tolog}'," which is worth}- of an extended notice. 



He has subdivided the genus Monticulipora into five subgenera, 

 viz. : Heterotrypa, Diplotrypa, Monotrypa, Prasopora, and Perono- 

 pora. The characters are founded upon microscopic observations, and 

 their value, therefore, is not evident to an ordinary observer. 1 will 

 not undertake to sa}' that this subdivision is wholly without any foun- 

 dation, but that it is not without serious objections will be apparent 

 in the following review of the work, in contrast with his earlier deter- 

 minations. 



Monticulipora mammulata is left where D'Orbigny placed it in 

 1850, except that he refers it to the subgenus Heterotrypa. A form 

 which has been usually referred to this species, but more dense]} 7 " tuber 



* Cin. Quar. Jour. Sci., vol. i., p. 368 

 t Ohio Pal., vol. ii., p. 188. 



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