272 



HA RD Wl CKE 'S S CIENCE - G O SSI P. 



for the partially universal distribution of generic type. 

 There is also a paucity of this type among Devonian 

 fossils, and it is only when we arrive at the Car- 

 boniferous era that we come across the full develop- 

 ment of the genus Glaticonome : and these, passing 

 upwards into the Permian era, seem to have dwindled 

 down to a single species and ultimately became ex- 

 tinct before the close of the period ; so that the 

 Glauconome may be considered a peculiarly Paleozoic 

 Polyzoan. 



About fourteen species of this genus have been 

 figured and described. One belonging to the Silurian 

 era, one to the Devonian, eleven to the Carboniferous, 

 and one to the Permian. This is in connection with 

 our own formations in Great Britain, for on this 

 genus I am unable to make any observations respect- 

 ing foreign species. 



Of the eleven British Glaiicono/iw, seven are entirely 

 new to science, and from MS. communications from 

 Mr. J. Young, I learn that he has discovered another 

 specie to add to the above list. Even now in all 

 probability the number of distinct species and 

 varieties are not exhausted : so numerous and so 

 minute are some of the individuals. As the work on 

 this genus has been so ably performed by Prof. 

 Young, M.D., and Mr. John Young, F.G.S., of the 

 Hunterian Museum of Glasgow, I can do no more than 

 refer the student to their papers in the Proceedings of 

 the Nat. His. Soc. of Glasgow, for March 1875. But 

 for the general reader, and the student to whom the 

 above may be inaccessible, I here reproduce a most 

 useful list from the above paper, in which the authors 

 sum up the principal points of distinction between the 

 species : — 



I have not satisfied myself yet as to the geographical 

 range of the genus, as my material gives to me only 

 a few scanty fragments from the several English 

 localities with which I am familiar. 



Until quite recently I was not aware of the exist- 

 ence of the Glauconome stellipora in England, but 

 examining more minutely than I had hitherto done 

 my Richmond material, I came across several frag- 

 ments of the variety named by Messrs. Young, 

 G. stellipora nobis. The fragments of species are not 

 so well preserved as are the Scottish fragments, 

 neither are the stellar markings over the pores so per- 

 fect, but the habit of the species is as distinctly 

 marked. I have not yet found Actinostoinia feues- 

 tratmn, another stellar species of the fenestrate forms 

 of Polyzoa. 



Under the two families of the Cyclostoinata, given 

 by Busk in his work on the Crag Polyzoa — 

 Diastoporida: and Cerioporidce — ^several genera may 

 be given, but the species of these have not yet been 

 so sufficiently worked out as to be as yet exhaustive. 

 M'Coy, I believe, gives only one specie oi Diastopora, 

 the D. viegastonia of the Carboniferous Limestone of 

 Ireland. But the form of this parasitic Polyzoa 

 varies so much that it is difficult to classify all the 

 Diastopora under this one head. One specimen now 

 before me from Richmond, in Yorkshire, is the finest 

 I have ever seen, and the marginal edges of this are 

 broken so that I have not a perfect specimen ; 

 another specimen, parasitic on Fenestella, is so 

 delicate as to be scarcely more than ^ of an inch 

 in diameter ; but all may be classed under the generic 

 description given by M'Coy under the genus Beri- 

 nicea of Lamarck. " Corallum encrusting foreign 



Name of species. 



Glauconome bipinnata, Phillips 



G. gracilis, M'Coy 



G. grandis ,, 



G. pulcherima , , 



G. (Diplopora) marginalis 

 Young & Young 

 G. elegans ,, 



G. aspersa ,, 



G. flesicannala ,,, 



G. retioflexa ,, 



G. luxa ,, 



G. (Acanthopora) stellipora. 

 Young & Young 



Cells in interval 

 of branches. 



I 



3 

 I 



Cells. 



Pinnules. 



alternate 



opposite 



sub-alternate 



alternate 



opposite 

 alternate 



opposite or sub-alternate 



irregular 



sub-alternate 



alternate 

 sub-alternate 



I have left out of the above list a few points more 

 essential to the specialist than to the general student. 

 All of the above species, together with many 

 varieties, are found in the rich shales of Hairmyres ; 

 and as I have specimens of the whole of the 

 species in my cabinet, I can speak positively of the 

 accuracy with which both Dr. and Mr. J. Young 

 have done their work. One species, however, I have 

 only an MS. sketch of, and this Mr, John Young 

 calls G. diplopora. 



bodies, composed of very thin, calcareous foliaceous 

 base, bearing numerous, ovate, distinctly separated 

 cells, not piled ; aperture round near the broad 

 anterior ends."* 



The generic character given by Busk of the Cerio- 

 poriihe is ' ' Polyzoarium, solid or lamellar, erect, or 

 decumbent (sometimes encrusting?), simple or 

 branched: cells contiguous, crowded." f But 



* M'Coy 's "Carb. Fossils of Ireland." 

 1" Busk, Crag Polyzoa. 



