COEALS OF THE COENIFEBOUS LIMESTONE. 237 



ings, but it has more than twice as many septa. More perfect speci- 

 mens, I feel satisfied, will prove this species to be distinct. 

 Position and locality : Corniferous limestone, Columbus, Ohio. 



Zapheentis peolifica, Billings. 



Zaphrentis prolifica, Billings ; Canadian Journal (new series), Vol. IV., p. 121, figs. 22, 23. 

 Zaphrentis prolifica, Nicholson ; Eept. on the Palaeontology of Ontario, pi. 3, figs. 2, 2a. 

 Heterophreniis prolifioa, Billings ; Canadian Naturalist (new series). Vol. VII., No. 4, 

 March, 1874. 



" Corallum simple, turbinate, curved, expanding to a width of from 

 eighteen to twenty four lines in a length of from two to four inches. 

 Surface with a few undulations of growth. Septal strife, eight to ten 

 near the base, and six to eight in the upper part, in a width of three 

 lines. Septa from about one hundred to one hundred and twenty at the 

 margin, where they are all rounded; most common number from one 

 hundred to one hundred and ten. In general they alternate in size at 

 the margin, the small ones becoming obsolete on approaching the bot- 

 tom of the calice, the large ones more elevated and sharp-edged. The 

 septal fossette is large and deep, of a pyriform shape, gradually enlarging 

 from the oater wall inwards for one-third, or a little more, of the diameter 

 of the coral, at the bottom of the calice. Its inner extremity is usually 

 broadly rounded, or, sometimes, straightish in the middle. It cuts off 

 the inner edges of from eight to twelve of the principal septa, which 

 may be seen descending into it to various depths. The surface layer of 

 the bottom of the cup extends the whole width, bending down a little 

 near the margin, as in Zaphrentis, and uniting with the inner wall of the 

 cup all around. It thus seems to represent one of the tabulae of a 

 Zaphrentis." (Billings, Canadian Naturalist, Vol. VII., No. 4, p. 237.) 

 The bottom of the calice is stated to be either smooth or to be furnished 

 with a more or less well-developed pseudo-columella. 



Mr. Billings (loc. cit ) forms a new genus for the reception of this and 

 some allied forms, under the name of Heterophreniis. The only charac- 

 ters which are stated to separate this genus from Zaphrentis are the exist- 

 ence of a pseudo-columella, and the fact that " there is apparently only 

 a single transverse diaphragm, and this forms the floor of the cup." I 

 do not feel myself at present in the position to be able to pronounce any 

 opinion as to the validity of the genus thus proposed by Mr. Billings. I 

 shall, however, in the meanwhile leave this pretty little coral in the 

 genus Zaphrentis, having myself seen no examples exhibiting the char- 

 acters quoted by Mr. Billings. 



