SPONGES, GRAPTOLITES, CORALS. 67 
Lepidolites, Cerionites. ] 
LEPIDOLITES, Ulrich.* 
PLATE F, FIGS. 11, 12. 
1879. Lepidolites, ULricu. Jour. Cincinnati Soc. Nat. Hist., vol. ii, p. 20. 
1885. Ischadites, JAMES. Ibidem, vol. viii, p. 163. 
1891. Receptaculites, JAMES. Ibidem, vol. xiv, p. 60. 
Lepidolites is closely related to Ischadites, but possesses a few features that will not 
allow it at present to be regarded as synonymous with the latter. The spicular 
head-plates in Ischadites Dr. Hinde (op. cit. p. 812) describes as follows: “As arule 
the margins of the plates appear to fit closely and evenly to each other so as not to 
leave any interspace between their edges, but in some cases the upper or front mar- 
gins seem to be slightly elevated as if they imbricated over the lower or hind margins 
of the spicular plates immediately in front, and left a small intermediate space, now 
filled with the matrix.” The head-plates in Lepidolites are very thin, strongly 
imbricating and wavy along their edges. While these sponges are more or less 
distorted, this overlapping character of the plates cannot be ascribed to pressure. 
Again, in Ischadites the head-plates increase in diameter from the nucleus to the 
zonal region, and then decrease in size towards the summit, but in Lepidolites, they 
gradually become larger from the center of the base to the upper portion of the 
sponge. The vertical or fifth ray of the spicules in Lepidolites is very short and 
terminates bluntly, while in Jschadites it is long and slender, gradually tapering and 
terminating in a point. This ray (the fifth) does not project free into the cavity, but 
lies flat and directed downward, with neighboring ones side by side, so that the 
result of the arrangement is an imbrication comparable with narrow shingles. 
L. proxHautti Ulrich. 
1879. Lepidolites aickhauti ULRicH. Jour. Cincinnati Soc. Nat. Hist., vol. ii, p. 21, pl. 7, figs. 17-17b. 
1879. Lepidolites clongatus ULRIcH. Ibidem, p. 22, pl. 7, fig. 16. 
1885. Ischadites dickhauti JAMES. Jour. Cincinnati Soc. Nat. Hist., vol. viii, p. 165. 
1891. Receptaculites dickhauti JAMES. Ibidem, vol. xiv, p. 63. 
Mr. Ulrich agrees that the name ZL. elongatus is superfluous. 
Formation and locality—Cincinnati group ; Covington, Kentucky. 
CERIONITES, Meek and Worthen. 
1868. Cerionites, MEEK and WORTHEN. Geological Survey of Illinois, vol. iii, p. 346. 
Type Lunulites? dactylioides OWEN. 
C. DACTYLIOIDES Owen, sp. 
1844. Lunulites ?dactioloides OWEN. Geological Report Lowa, Wisconsin and Illinois, p. 69, pl. 13, fig. 4. 
1868. Cerionites (Pasceolus?) dactylioides MEEK and WoRTHEN. Geological Survey of Illinois, vol. iii, 
p. 346, pl. 5, fig. 2. 
1884. Cerionites dactyloides WHITFIELD. Geology of Wisconsin, vol. iv, p. 267, pl. 13, figs. 1-3. 
Formation and locality.—Niagara limestone ; Carroll county, Illinois, and Waukesha, Wisconsin. 
*We are indebted to Mr. Ulrich for the opportunity of studying his type material. 
