168 Cincinnati Society of Natural History. 
Formation and locality : Cincinnati Group. Rather near the tops 
of the hills back of Cincinnati, O., and at Hamilton, O. 
SPATIOPERA MONTIFERA, Nn. sp. (PI. VI., figs. 1 and la, and Pl. VIL, 
fig. 8.) 
Zoarium parasitically attached to the shells of Orthoceras, over 
which it forms a thin and expanded crust ; from .02 to .05 of an inch 
in thickness. .Surface exhibiting a number of long, narrow monticules, 
all drawn out in one direction, and arranged in more or less regular 
longitudinal and diagonally intersecting series. The long diameter of 
these monticules varies from .17 to .35 of an inch, their width rarely 
exceeding .1 of an inch, their height varying from .05 to .1 af an inch. 
Four or five may be counted in the length of 1 inch. The cells over 
all portions of the surface are subequal, moderately thin walled, sub- 
angular, with an average diameter of 5th of an inch. A variable 
number of minute cells is usually placed among the cells occupying 
the monticules. 
Tangential sections (Pl. VI., fig. 1) are remarkable for the peculiar 
wall structure, already noticed in S. aspera. But in this species the 
light and dark shades of the wall contrast so strongly, and are so in- 
termingled that in some places the walls have a spongy appearance. 
A few spiniform tubuli were observed. Longitudinal sections (Pl. VI., 
fig. la) show that an occasional diaphragm is present. .A few irregu- 
larly constricted, small or interstitial tubes may he noticed, in which 
the diaphragms are numerous. 
I have little doubt that when Dr. Nicholson wrote the description of 
Chetetes corticans, which he now regards as identical with Edwards 
and Haimes’ Chetetes twberculatus, he had before him three different 
species, of which 8S, montifera was one. The other two were typical 
Chetetes tuberculatus, and the form which was described by mein this 
JOURNAL as Atactopora maculata. As; however, Dr. Nicholson has 
abandoned his name C. corticans, I have deemed it more advisable to give 
this form a new name than to re-establish an abandoned one. S. mon- 
tifera is distinguished from S. tuberculata, Ed. & H., as well as from 
all the parasitic bryozoa of the Cincinnati group, by its remarkably 
developed monticules. 
Formation and locality: Cincinnati group; rather rare in the upper 
layers of the Cincinnati group, at Clarksville, Oxford, and other 
localities in Southwestern Ohio. It is not found at Cincinnati or any 
equivalent localities. 
[TO BE CONTINUED. | 
