PORIFERA OF THE UL.M.B.C. DISTRICT. 37 
specimens at his disposal. Of one of them he gives the 
following description :—‘‘ The pedicel is barely an inch in 
height; at an inch and a half from the base it has divided 
into four primary branches; within one inch from their 
origin these primary branches each divide dichotomously, 
and this mode of division continues, with a single exception 
of one branch dividing trichotomously, so that at four inches 
from the base there are as many as twenty-two, all nearly 
in the same plane, assuming a fan-shaped series of 
branches, eight inches in height by about the same extent 
in width. The branches are cylindrical,” &c. 
A transverse section through this sponge shows us that 
it consists of a solid mass without central cavity. The 
oscula are numerous, although visible only in those 
sections. Bowerbank has stated that the ‘‘oscula and 
pores are inconspicuous.” The oscula open into irregular 
cavities, branching throughout the whole sponge. ‘The 
spicules consist firstly of styli of two different sizes. The 
large styli measure from 1°2 mm. to 1°5 mm. by 0'013 mm.; 
the shorter ones from 0°42 mm. to 0°45 mm. by 0°004 mm. 
Besides that, we find spined styl, 0°124 mm. by 0°0055 mm. 
The ordinary styli are arranged either in bundles running 
parallel to the longitudinal axis of the sponge, or they 
form bundles standing at right angles to the longitudinal 
axis, and project for about two-thirds of their length 
through the ectoderm. This latter point had been noticed 
by Bowerbank,* who said that ‘‘in the dried condition of 
the sponge the fasciculi of radiating spicula project from the 
central cylinder of the skeleton to the extent of at least 
one-third of the whole diameter of the branch,’ but he 
adds, ‘it is probable that in a living state their apices 
would be barely visible beyond the dermal membrane.”’ 
As I have stated already, sections through a well preserved 
* Bowerbank, ‘‘ British Spongiade,” vol. ii., p. 101. 
