imperfectly-known Species of Corals. 23 



I call Monticulipora Winteri, both externally and bj means of 

 microscopic sections, and I have totally failed to detect any 

 traces of mural pores. In the second place, my own limited 

 collections are sufficient to show me the impossibility of pro- 

 nouncing positively upon the structuve and affinities of any 

 individual specimens, even of a known and marked external 

 figure, and from a known locality, unless a microscopic exa- 

 mination has been instituted ; and the form now under discus- 

 sion is an excellent example of what I now say. I find, 

 namely, that I possess in the collection which I personally 

 made at Gees three quite distinct forms, all of which so closely 

 resemble each other externally that, until I had made thin 

 sections of them, I had placed them together in the same 

 tray, as indubitably belonging to the same species. One of 

 these three forms is the type which I have described under 

 the name of Monticulipora Winteri ; another is a true Fistuli- 

 pora, as defined by M'Coy ; and the third is a genuine Alve- 

 olites^ and is provided with numerous and well-marked mural 

 pores. The form described by Quenstedt under the name of 

 Favosites fihroglohosus (Petrefact. Deutschlands, Bd. vi. S. 15, 

 Taf. 143) is one with which I am unfortunately unacquainted ; 

 but it might, so far as external form is concerned, easily be 

 any one of the three forms which I have just enumerated ; or 

 it might be a fourth, quite distinct form. In any case, the 

 facts I have mentioned are quite sufficient to prove that the 

 occurrence of a fossil at a particular locality and its possession 

 of a well-marked external form cannot be allowed to count 

 for any thing (so far as the more delicately constructed species 

 of corals are concerned) when we come to determine generic 

 or specific relations and affinities. 



9. Associated with the preceding were species of Aulopora, 

 CyatJwphyllum, Zaphrentis, and Cystijjhyllumj which my 

 leisure would not permit me to specifically determine. M. 

 CEhlert's collection also contained some interesting Stromato- 

 poroids, which I may take the opportunity of describing on 

 some future occasion. 



EXPLANATION OF PLATE I. 



Fig. 1. A fragment of Striatopora pachystoma, Nich., of the natural size. 

 Fig. 1 a. Portion of a tangential section of the same, enlarged seven 



times. 

 Fig. 1 h. Part of a vertical section of the same, enlarged seven times, 



showing the thickened walls and a few mural pores. 

 Fig. 2. A fragment of Pachypora Gihlerti, Nich., of the natural size. 

 Fig. 2 a. A small portion of the surface of the same, enlarged eighteen 



times, showing the form of the calices. 

 Fig. 2 b. Portion of a tangential section of the same, enlarged eighteen 



