22 



of the genus are readily recognized by their thin epitheca, the presence of tabulae extending 

 quite across the theca as unbroken partitions, the extension of the septa to or near to the 

 centre of the theca, the absence of a columella, and the generally open and uninterrupted 

 condition of the interseptal loculi, except for their being partitioned off by the tabulae. In 

 some of the forms of the genus, ho.wever, the continuity of the interseptal loculi is interfered 

 with, not only by the tabulas, but ty vesicular dissepiments which appear to be independent 

 of the tabulas ; so that there is a central tabulate area, and an external vesicular area. There 

 is also evidence that the tabulae, though extending quite to the epitheca, are, in their exterior 

 portion at any rate, of the nature of dissepiments placed nearly at the same level in successive 

 interseptal loculi. According to Mr. Billings, also, a well developed or rudimentary columella 

 may be present in Z. prolifica, this structure being otherwise unknown in the genus. 



Three species of Zaphrentis, viz. : Z. glgantea (Lesueur), Z. prolifica (Billings), and 

 Z. spatiosa (Hillings), have been already recorded from the Corniferous Limestone of Western 

 Ontario, all of which have come under my notice, whilst I have to record an apparently un- 

 described form. I have also a small cylindrical, spinulose form, allied to Z. spinulosa (Edw. 

 & H.), or to Z. spinuli/era(H.a\l), though apparently distinct, which, in the absence of specimens 

 showing the internal structure, I shall leave undescribed. 



11. ZAPHRENTIS GIGANTEA (Lesueur). 

 (Plate III. Pigs. 1, 



Caryophyllia gigantea (Lesueur). 



Zaphrentis gigantea (Edwards & Haime). Pol. Poss. des Terrs. Pal. PI. IV., Fig. 1. 



Zaphrentis gigantea (Billings). Canadian Journal, New Series, Vol. IV., p. 121. 



Corallum simple, cylindro-conic, varying from a few inches up to two feet or more in 

 length, and from one and a' half to three inches in diameter, usually more or less curved. 

 Cavity of the theca partitioned off by a well developed series of tabulae, which are more or 

 less flexuous centrally and are bent downwards as they approach the epitheca. Septa from 

 seventy to one hundred or more in number, unequally developed, or alternately large and small, 

 extending upon the upper surface of the tabulae nearly to the centre, where they are usually 

 more or less flexuous. A single well marked septal fossette upon one side, extending nearly to 

 the centre. Epitheca with numerous shallow encircling ridges and annulations of growth, which 

 vary in size but are not sharp-edged ; and also with costae corresponding with the septa within. 



According to Mr. Billings, the septa in this species vary in number from seventy to 

 eighty. In the examples which I have seen, however, the septa are alternately large and 

 small and, counting in those of both sizes, attain to the number of one hundred or more. 

 They thus come to resemble large specimens of the form described by Mr. Billings, under 

 the name of Z. prolifica,, from which they may be distinguished by the fact that the latter 

 species is not said to attain a length of over five inches, or a little more, whilst the radiating 

 septa reach the number of one hundred and twenty, or one hundred and fifty. Our specimens, 

 on the other hand, must have attained a length of from nine to twelve inches or more, and do not 

 appear to have more than one hundred and ten septa at the utmost, whilst their form is cylin- 

 drical, or cylindro conical, and not turbinate. I am not satisfied, however, that all the examples 

 which I have here included under Z. gigantea, are really referrible to this species, nor that the 

 large and small forms of Z. 'prolifica (Billings), can be retained under a single specific title. 

 Zaphrentis gigantea (Lesueur) must not be confounded with the large Carboniferous species 

 described by Michelin and McCoy, under the name of Caninia (Zaphrentis) gigantea, and by 

 Edwards and Haime, under the name of Zaphrentis cylindrica. 



Locality and Formation. Corniferous Limestone of Kidgeway, Port Colborne, Walpole, 

 and numerous other localities in Western Ontario. 

 ft 



12. ZAPHRENTIS FENESTRATA (Nicholson). 



(Plate IV. Fig. 1.) 



Zaphrentis fenestrata, (Nicholson), Canadian Naturalist, Vol. vii., No. 3, 1873. 



Corallum simple, cylindro-conical, curved. Tabulae well developed, remote, bending 

 downwards as they approach the outer wall. Septa strong, equally developed, extending 



