Mr Etheridge on Fossils from Bowen River Coalfield. 277 



other hand, if we look a little more minutely into the subject, 

 we shall, I think, find a much more satisfactory reason for 

 the separation of the two forms. 



Lonsdale long ago pointed out, in describing* his Fenestella 

 avijjla, that the polyzoarium was bilamellar, the outer layer 

 or back of the branches being "composed of a uniform 

 crust," upon which are seated the tubular cells, at right 

 angles, or a little obliquely to the former. This structure is 

 exceedingly well shown in Mr Lonsdale's figure given in 

 Count Strzelecki's work;*!* but we are indebted for a further 

 and fuller exposition of it to Professor W. King. This author 

 showed^ that in his genus Phyllopora, and some other Palaeo- 

 zoic genera, the frond was bilamellar or bistructural, consist- 

 ing of a lamina of capillary tubes, called the basal plate, and 

 an outer lamina of cellules, arranged more or less at right 

 angles to and on this. On the other hand, he states that in 

 the Elasmoporid(E (== Beteporidcp, auct.) the frond is uni- 

 lamello-celluliferous, " composed of one lamina, consisting 

 simply of cellules or polypidoms." As before stated, this 

 bilamellar structure has been shown to exist in Frotoretepora 

 amyla by Lonsdale, and it appears to me a character of much 

 more generic value than the mere arrangement only of the 

 fenestrules. 



Two forms of Protoreteyora occur amongst Mr Jack's fos- 

 sils — one, a bold and distinctly marked form, which I propose 

 to call P. Koninchii; the other possessing all the character of 

 P. amyla, the type of the genus, except that it is of a much 

 smaller habit. 



Protoretepora Koninchii, sp. nov. 



Sp. char. — Polyzoarium infundibuliform, curled and much 

 crumpled, of large extent. Fenestrules, small round, separated 

 by wide interspaces (interstitial), and arranged in quincunx. 

 Interstitial surface occupied by from five to ten rows of cell 

 apertures between contiguous fenestrules. Cells with hexa- 

 gonal or polygonal bases. Basal plate thin and striated. 



* Darwin's "Volcanic Islands," pp. 163, 164. 



+ Ihicl, t. 9, f. U. 



X Annals Nat. Hist., 1849, pp. 383-90; Alon. Perm. Foss., p. 42. 



