176 THE GENUS MONTICULIPORA. 



authority upon such a subject is justly of great weight, has 

 suggested (N. Jahrb. fiir Min., Geo!., unci Pal., 1880, p. 438) 

 that the species is really the same as the previously described 

 Favositcs fibroglobos2Ls of Ouenstedt, which occurs at the same 

 locality (Gees, near Gerolstein). In a careful examination, 

 however, of both my German and French specimens, carried 

 on both externally and by means of microscopic sections, I 

 have been quite unable to detect any evidence of the existence 

 of mural pores. I do not in the least desire to call in question 

 the validity of Professor Ouenstedt's species ; nor, though I un- 

 fortunately have not at this moment access to its description, 

 do I question its external resemblance to ]\I. IVinteri. It is, 

 however, quite clear that in a point of this kind no reliance 

 can be placed upon anything of the nature of external simili- 

 tude, however close, or, in fact, upon anything but identity of 

 internal structure as demonstrated by the examination of thin 

 sections. Now, I find that in the comparatively small collec- 

 tion which I myself made at Gees, three quite distinct forms 

 are really present, all so like each other that, prior to micro- 

 scopic examination, I had unhesitatingly placed them together 

 as belonging beyond doubt to the same species. Thin sections 

 of these, however, show that these three forms are all widely 

 different from one another in internal structure. One of them 

 is the form here described under the name of iMonticidipora 

 W inter i; another is a true FisttLlipora, as that genus is de- 

 fined by M'Coy ; and the third is a genuine Alveolites, and 

 is provided with numerous and well-marked mural pores. 

 The form described by Ouenstedt under the name of Favosites 

 fibroglobos2is (Petref Deutschlands, Bd. VI. S. 15, Taf 143) is 

 one that, as previously remarked, I am not acquainted with ; 

 but, so far as its external form is concerned, it might quite well 

 be any one of the three forms which I have just mentioned, 

 or it might be a quite distinct form.^ At any rate, the facts 



' In this connection I may point out a source of fallacy in a number of the speci- 

 mens of the Eifel corals. In many of these the fossil is largely impregnated with 

 globular grains of peroxide of iron, and these in thin sections often simulate mural 



