72 
AUG. F. FOERSTE 
Rhabdosome originally infundibuliform, with sides diverging 
at angles varying in different specimens from 45° to 75°. The 
base of this rhabdosome tends to be pointed. Its length usually 
is from 25 to 30 mm. Between 12 and 15 branches occupy a 
width of 10 mm. The branches vary from 0.3 to almost 0.5 
mm. in width, and tend to be narrower than the spaces between 
them. Usually the branches are almost straight. They are 
connected by dissepiments forming large angles (usually nearly 
right angles) with the branches. Seven or 8 of these dissepi- 
ments occur in a length of 5 mm. Along the greater part of their 
length these dissepiments are only slightly larger than 0.05 
mm., but they enlarge near contact with the branches. The 
resulting meshes are quadrangular. The apertures of the thecae 
are not distinctly preserved in any specimen at hand but in 
several specimens the worn surfaces show rounded or elliptical 
outlines which are regarded as locating the thecae. Of these 
there are about 9 in a length of 5 mm., the number decreasing in 
some specimens to 8 in this distance. 
I.ocality and formation. — In the quarr^^ north of the deep 
ravine at Credit Forks, Ontario, a quarter of a mile west of the 
railroad station. In the basal part of the Manitoulin dolomite, 
a member of the Medinan. 
Remarks. — In the original description of Dictyonema scalari- 
forme the number of thecae was given as 13 in a length of 5 mm. 
Since in the Credit Forks specimens only 9 were noticed in the 
<=?ame distance there is a possibility that a distinct form here is 
represented, for which the name Dictyonema scalariforme credi- 
tensis is proposed. 
D. A LOWER MEDINAN FAUNA BELOW THE BRASSFIELD LIMESTONE 
IN OHIO 
In the quarry half a mile northeast of Centerville, Ohio, and 
about ^ of a mile northwest of the railroad station, the full section 
of the Brassfield limestone and of the Dayton limestone is ex- 
posed. At one point the Dayton limestone is overlain by the 
lower part of the argillaceous layers formerly known as the 
Niagara shale, and at present doubtfully referred to the Alger 
