OF DENISON UNIVERSITY. 
89 
peristome carrying from four to six comparatively strong tubercles ; 
the latter are more or less regularly arranged and project slightly over 
the apertures. Between the apertures, which are widely separate, the 
surface is transversed either by irregularly interrupted and unequal 
longitudinal ridges or by nearly straight continuous ones between 
which the apertures are ranged in longitudinal series with about nine 
in 5 mm. When the more regular arrangement prevails the strong 
ridges may unite with the spiniferous peristomes or pass by them on 
or both sides, while the concave space between succeeding apertures 
exhibits one or two thinner and less elevated ridges which continue 
from one peristome to the next in either a straight or an oblique direc- 
tion. The length of the spaces traversed by them equals between two 
and three times the diameter of the zooecia apertures. 
This interesting and peculiar species cannot be confounded with 
any other form of Streblotrypa known to me. In fact, it is even pos- 
sible (as indicated above) that it does not belong to this genus at all 
but rather to Leioclcma^ the denticulate apertures being very suggestive 
of the most typical species of that genus. Still, taking all the known 
characters into consideration, it does not now appear probable that 
this suggestive external feature will be borne out by an examination of 
the interior. I regret to say that the preservation of the specimens at 
hand did not permit me to apply this test. 
Formation and locality : — Cuyahoga shales of the Waverly series, 
at Richfield, Lodi and several localities in Cuyahoga Co., O. 
Collections of Prof. C. L. Herrick and E. O. Ulrich. 
RHOMBOPORA I NCRASSATA. Ulrich. 
(Plate XIV, Fig. 16, and (?) i6a.) 
Rhombopora incrassaia, Ulrich. 111 . Geol. Surv. vol. VIII, pi. LXX, figs. 12, 
I2a. (In press.) 
The Ohio specimens of this species seem to agree in every particu- 
lar with the typical examples coming from shales of the Keokuk group 
of Kentucky. 
The original of fig. i6a is referred here with some doubt as it had 
more acanthopores (now represented by small pores) than I have ever 
seen on examples of the species. Were it not for the strong internal 
thickening, in which it greatly resembles R. incrassata, I would place 
it with the peculiar R. spiralis^ Ulrich.* The originals of the last 
