THE CARBONIFEROUS PENESTELLIDiE. 



185 



of Palceocoryne, eighty-five are either attached to the polypitc- 

 face of Fenestella nodulosa or associated with it, while twelve 

 only are free and unattached. In no one instance is there a sus- 

 picion that the species is any other than the one mentioned. Simi- 

 lar evidence to this I get in another way. I have more than one 

 hundred specimens of F. nodulosa from the shales of Halkin 

 Mountain, but out of them not one example showing the poriferous 

 face ; all without exception present to view the reverse side. This 

 I explain by supposing that, as it is on the poriferous face of Fenes- 

 tella that Palceocoryne finds its seat, that face has in consequence 

 held the more firmly of the two to the shale. This is really so ; for 

 the base of it may be detected by a slight bulging of the polyzoary 

 of the Fenestella, and its presence demonstrated by removing a 

 portion. There is no similar difficulty in obtaining the obverse 

 face of the other species from the same beds ; nor do the other 

 species present the appearance on the reverse face which I have 

 noticed in F. nodulosa. The concurrence of these two species may 

 be accidental : but I scarcely think so ; the extent of its occurrence 

 is not in favour of that idea ; so that I think we may conclude 

 that we have good evidence that Palceocoryne in the upper beds of 

 the Mountain Limestone is exclusively confined to the polyzoary of 

 Fenestella noclidosa, Phill. I may mention that I have found 

 Palceocoryne associated with F. nodulosa in the middle beds of 

 the Mountain-Limestone series of ISiorth "Wales, and also directly 

 seated upon the poriferous face of the same from the Calciferous 

 Sandstones of Scotland. I have previously pointed out that several 

 inferior organisms are parasitic upon or incrust the polyzoaria of Fe- 

 nestella, from Silurian times upwards — such as Hemitrypa, Aidopora, 

 Alveolites, and Diastopora ; and now Palceocoryne has to be added to 

 the list. In the case of the previous incrustations there is no doubt 

 that the parallel branches of the Fenestella afforded suitable base- 

 lines for the attachment of the incrusting coral. Whether there 

 was any thing more than this in the preference shown by Palceo- 

 coryne, is one of the problems to be worked out ; and it will, I 

 have no doubt, receive due attention at the hands of Prof. Martin 

 Duncan, to whom I have handed over my specimens of Palceocoryne 

 for further elucidation. 



Fenestella polyporata, Phill. Geol. Yorks. pi. i. figs. 19, 20. 



Fenestella midtiporata, M'Coy, Syn. Carb. Poss. Irel. pi. xxviii. 

 fig.9. 



intermedia, Prout, Trans. Acad. St. Louis, p. 231. 



variabilis, Prout, Trans. Acad. St. Louis, p. 231. 



Sp. char. — Polyzoanwn foliaceous at first, arising from a stem, 

 ultimately becoming a flat circular network. Interstices large, 

 broad, rounded, keeled. Dissepiments thin, one third the thick- 

 ness of the interstice, somewhat irregularly placed, not expanding 

 at junction with interstice. Fenestrules large and elongated, three 

 times as long as wide. Four fenestrules in the space of two lines 



