126 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



nearly equal on the margins of the calyces, where the sharp crested leaves 

 of the inside expand into low rounded rugae. The extension of the radial 

 crests toward the centre is subject to variations ; in some the central part 

 of the diaphragms remains smooth, and the crests are confined to their 

 peripheral circumference ; in others the crests reach as low carinas to the 

 centre and become irregularly entangled in their convergence, but these 

 central portions of the crests are merely superficial, and do not intersect 

 the diaphragms to form continuous vertical leaves. The number of lam- 

 ellae in calyces of about two and a half inches diameter is 150 to 160, 

 half of which are of the smaller size. Found in the upper Helderberg 

 limestones of Michigan, Canada, Ohio, and in the Western States.' " 

 (Lambe, 1899.) 



Localities and formation. — At Rama's farm, Cayuga, and at other local- 

 ities in Ontario; Corniferous limestone. 



Zaphrentis mirabilis, Billings. (Sp.) 

 Plate X., figs. 1, la, 16. 



Amplexus mirabilis, Billings. 1874. Canadian Naturalist, new series, vol. VII., p. 232. 



Zaphrentis invenusta, Billings. 1874. Ibid., p. 233. 



Zaphrentis Egeria, Billings, pars. 1874. Ibid., p. 234 (the third specimen mentioned in 



the description). 

 Zaphrentis subrecta, Billings. 1874. Ibid., p. 235. 

 Zaphrentis Leda, Billings. MS. 

 Zaphrentis mirabilis, Lambe. 1899. Ottawa Naturalist, vol. XII. , p. 255. 



"Original description. — ' Corallum sometimes abruptly curved in differ- 

 ent directions, expanding to a width of from fifteen to twenty lines in a 

 length of four or five inches from the base ; above which it becomes more 

 nearly cylindrical. Surface with fine engirdling striae, in general four 

 or five in the width of two lines, but in some places, the same number 

 occur in the width of one line. There are also numerous angular rings 

 of growth, distant from two to fifteen lines from each other, with sub- 

 concave spaces between. Septal costae rounded, distinctly defined by 

 sharp stria? between them, seven or eight in the width of three lines near 

 the base, and four or five in the same near the calice. There are 

 about forty large septa at the calice, where the diameter is about 

 eighteen lines, with the same number of small ones between them. The 

 larger have a depth of three or four lines and the smaller one line. All 

 of the septa are more or less curved, sometimes very tortuous. The 

 tabulae have not been observed. 



" 'The above description was drawn up from a specimen, eleven inches 

 in length, measured along all the curves. It is fifteen lines in diameter 

 at five inches from the base, and about eighteen lines at the cup. The 



