CORALS OF THE CORNIFEEOUS LIMESTONE. 235 



septal striae, and the absence of radiciform prolongations of the epitheca. 

 The forms to which it is most nearly allied are 0. cylind,ricum, Londs., C. 

 Grayi, Edw. and H., and C. sulcatum^ Billings; but the above characters 

 are amply sufficient to distinguish it. 



Zaphrentis Edwardsi, Nicholson. 



Plate 23, figs. 6, Qa. 



Corallum small, acutely conical, slightly curved towards the base. 

 Length, nine lines ; diameter of the calice, six lines. Ei)itheca with a 

 few obscure annulations of growth, and with well-marked longitudinal 

 striae corresponding with the septa. Calice circular, about three lines in 

 depth. A well-marked septal fossula on the curved side of the corallum, 

 extending from the center to the margin of the cup, with two smaller 

 and less conspicuous lateral fossuhe, which also extend from the center, 

 and are directed nearl}' at right angles to the main fossette. The main 

 fossule includes three of the primary septa, whilst the lateral fossules in- 

 clude a single primary septum each. Septa alternately large and small, 

 fifty-six in number altogether. The large septa reach the center of the 

 calice, where they are occasionally slightly bent, but do not unite with 

 one another. 



I am reluctant to add to the already long list of species of Zaphrentis, 

 but I am unable to refer this to any previouslj^ recorded form. It differs 

 from all the known species of the genus, except Z. Griffithi, Edw. and 

 Haime, in having two small lateral fossulas placed at right angles with 

 the main fossule, the latter being deep, extending to the center of the 

 visceral chamber, and situated on the dorsal side of the corallum. From 

 Z. Grifjithi the present species differs in its smaller size, its proportion- 

 ately deeper calice, its smaller number of septa, and its much less broadly 

 expanding form. 



Position and locality : Corniferous limestone, Columbus, Ohio. 



Zaphrentis Wortheni, Mcholson. 



Plate 23, figs. 5, 5a. 



Corallum small, conical, strongly curved, the calice being so oblique as 

 to be almost parallel with the long axis of the coral. Length, measured 

 along the greater curvature, fourteen lines; along the smaller curvature, 



