CORALS AND BRYOZOA. 
239 
may easily be distinguished from that form by the oval cell apertures, the 
presence of denticulations, and the absence of inter-apertural pits: the 
peristomes, denticulations and absence of interapertural pits, distinguish it 
from Cosc.inium cosciniforme. It is the only species of the genus at present 
known, from the Upper Helderberg and Hamilton groups, having a distinctly 
striated surface. 
Formation and locality. Hamilton group, Widder, Ontario, Canada. 
COSCINELLA, nov. gen. 
CoSCINELLA ELEGANTULA. 
PLATE LXIV, FIGS. 9-12. 
Zoarium consisting of an explanate frond, celluliferous on each face, with perfora¬ 
tions or fenestrules at somewhat regular distances from each other, the whole 
having the appearance of being composed of sinuous, anastomosing branches. 
Base spreading, adhering to Cyatliophylloid corals or other bodies; pedicel 
cylindrical, short, diameter about 18 mm.; fronds large, fragments occurring 
which have a length of 80 nun. and a width of 110 mm. The fenestrules 
vary in form from circular to elongate-oval, length generally from 1.50 to 2 
mm., width a little more than 1 mm., both larger and smaller fenestrules 
occurring, usually distant about 3.50 mm. A transverse section of the frond 
between the fenestrules is lenticular, greatest thickness 1.30 mm. The 
mesotheca is very thin, marked by arching undulations of growth and also 
by longitudinal striations, caused by the recumbent portion of the cell 
tubes. Cells tubular, cylindrical, for one-half their length parallel with, 
and resting upon the mesotheca, then abruptly bending and continuing 
rectangularly to their former course, opening directly outward. Intercellular 
tissue composed of tubuli, with very closely disposed septa, or of vesicles so 
disposed that they have the appearance of septate tubuli. Cell apertures cir¬ 
cular, diameter .25 mm., closely disposed, very frequently in contact, seldom 
separated by more than one-half the diameter of an aperture, usually by not 
more than one-third, generally irregularly disposed, but sometimes forming 
