84 
BULLETIN OF THE LABORATORIES 
the cells. Typically one cell is placed at each corner of the fenestrule 
at the junction of the dissepiments with the branches, another cell is 
situated on each side of the fenestrule half way between the two cells 
already located; the number of cells is therefore typically twice 
that of the dissepiments ; but occasionally two cells may fall in this . 
intermediate region and the next cell is thrust to a position just above 
the next dissepiment, but the typical distribution is easily recognized 
in the complete individual. The cell mouths are very large, so that 
the corners of the fenestrules are rounded and near the middle they are 
constricted, giving a very peculiar appearance to the fenestrules. The 
broad cells thus give the branches a very characteristic appearance 
which is suggested in the specific name limbattis, bordered. 
Here all similarity ceases. The specimens vary from small, fine, 
delicate forms, to those which are quite coarse. It seems bold almost 
to associate such forms under one specific name, but we fail to find 
specific characteristics, although we have abundant material and prefer 
to designate one well-defined species, to naming several which inter- 
mediate forms refuse to admit. Considering them as one species we 
have the following description of the non-poriferous side. Dissepi- 
ments from one-fourth to almost one-half the size of the branches. 
Fenestrules oblong, the corners angular, varying to coarsely granular, 
then often with quite large granules in distinct longitudinal rows, often 
longitudinally striated, especially in worn specimens. Branches from 
lo to 13 in a width of 5 mm., dissepiments 9.5 to 13 in the same length. 
As types of this species we take the smallest specimens. 
XI. Fenestella limbatus, var. remotus. 
{Plate VII, Fig. II.) 
A variety having all the other features of this species differs only 
in having the dissepiments relatively farther removed from each other 
as shown by the following measurements: 10.5 branches occupy a 
width of 5 mm, 6.5 dissepiments occupy the same distance in length. 
Found with the above. 
