76 
AUG. F. FOERSTE 
its glabella and in the divergence of the dorsal furrows posteri- 
orly, but differs in having a more rounded anterior margin on 
the glabella, in this respect agreeing with Calymene meeki, a 
species from the Maysville formation of Ohio, Indiana, and Ken- 
tucky. In Calymene meeki the ribs of the pygidium show only 
a trace of an impressed groove along their median line. The 
pygidium of the Don Valley specimens is unknown. 
Calymene retrorsa minuens var. nov. 
Plate XYIII, fig. 4 
Compared with Calymene meeki Foerste (Bull. Sci. Lab. 
Denison Univ., 16, 1910, p. 84, pi. 3, fig. 18; also fig. 3 on plate 
XVIII accompanying this paper), Calymene retrorsa Foerste 
(Bull. Sci. Lab. Denison Univ., 16, 1910, p. 85, pi. 3, fig. 19; 
also fig. 2 on plate XVIII herewith) is characterized by rounded 
genal angles; a narrower, less triangular cephalon; and a shorter, 
less nasute anterior border, in front of the glabella. Calymene 
meeki is characteristic of the Maysville formation; and Calymene 
retrorsa is characteristic of the Waynesville member of the 
Richmond formation. 
In the Whitewater member of the Richmond, both in Ohio 
and Indiana, a small form of Calymene occurs which has all of 
the characteristics of Calymene retrorsa but is constantly of 
smaller size. For this form the varietal name minuens is pro- 
posed. The specimen here figured (plate XVIII, fig. 4) was 
obtained at Richmond, Indiana, by John Misener. 
In Ohio, Calymene retrorsa minuens is found in Clinton county, 
on a little branch entering Cowan creek, about a mile southeast 
of the entrance of the latter into Todd’s Fork. Here the Liberty 
member of the Richmond formation is 43 feet thick. In its 
upper part, through a vertical range of 5 feet, Pachydictya 
fenestelliformis is fairly common, and a large form of Strep- 
telasma rusticum is abundant. The even-bedded character of 
the Liberty member is continued into the lower part of the 
Whitewater member for a distance of II feet. Above this level 
the Whitewater strata become argillaceous and more or less 
nodular, and specimens of Calymene retrorsa minuens begins to 
make their appearance. 
