BRYOZOA. Oe 
Crepipora spatiosa. ] 
Mesopores very few. In vertical sections the walls are thin, with faint transverse 
lineation, and somewhat irregular. Diaphragms occur sparingly and at unequal 
intervals in the zocecial tubes, but in the mesopores which, being few, are not often 
seen, they are numerous. 
The absence of clusters of large cells and the greater average size of the 
ordinary zocecia will distinguish this peculiar species from associated Bryozoa 
having a similar mode of growth. 
Formation and locality—Rare in the upper third of the Trenton shales at St. Paul, Minnesota. 
CREPIPORA SPATIOSA, 7. Sp. 
(Not figured.) 
This name is proposed for a massive or heavy lamellate form that occurs in the 
Bryozoa layers at the top of the Trenton near Harrodsburg and Frankfort, Ken- 
tucky. It is closely related to C. hemispherica Ulrich (upper beds of Hudson River 
group in Illinois), on the one side, and C. perampla on the other. From the first it 
differs in the greater size and different shape of its zoarium, in haying thinner walls 
and fewer diaphragms, and less distinct lunarium. The second has larger zocecia 
and even less developed lunarium, but in other respects is very similar to the Ken- 
tucky species. 
Specimens of this species may attain a diameter of 300 mm. with a thickness of 
from 50 to 100 mm. Of the ordinary zoccia twelve occur in 5mm. Diaphragms 
0.4 to 1.0 mm. apart. 
CREPIPORA PERAMPLA, 2. Sp. 
PLATE XXVIII, FIGS. 29-82. 
Three specimens have been seen of this. One, about 70 mm. in diameter and 
33 high, is hemispheric, with the base concave and the margin flaring slightly. The 
others are larger (about 95 mm. in diameter) and, though worn, the basal part of 
the zoarium seems to have been convex instead of concave. Zocecia large, with very 
thin walls, genérally of angular shapes, the pentagonal and hexagonal more common 
than the subrhomboidal; those of the average size about 0.5 mm. in diameter, with 
nine or tenin5 mm. At intervals of 5 or 6 mm. clusters of tubes of more or less 
decidedly larger size than the ordinary are to be observed. Some of these may 
attain a width of 0.9 mm., but as a rule their size varies between 0.6 and 0.8 mm. 
Mesopores very few. 
