Sponges of Palau, I — Bergquist 
171 
SURFACE: Deeply folded and raised into 
mounds. The dermal membrane is 60-125/a 
thick, and contains a more or less regular spicule 
reticulum and large quantities of fine calcare- 
ous debris. Projecting spicules from the sub- 
dermal brushes render the surface slightly hispid. 
Small oscular areas are dispersed irregularly 
over the surface, each giving access to a large 
subdermal cavity. Circular and oval pores are 
evenly scattered over the entire dermal mem- 
brane and range from 62-100/a in diameter. 
SKELETON: The dermal skeleton is made up 
of a series of intersecting fibres varying from 
1-8 spicules wide (4.5-38 /a) and delimiting 
roughly triangular meshes, 62-3 7 5/a across. In 
addition to the megasclere skeleton, the dermis 
contains isolated anisochelae, usually of the 
smaller category. Immediately beneath the der- 
mal membrane are huge subdermal cavities 
% 
Fig. 23 a. Mycale cavernosa n. sp. Sta. 125. Holo- 
type. usnm 23703. 
which extend deep into the interior of the 
sponge. The primary fibres of the endosome 
are stout, sparsely branched, and invested with 
spongin, which is just visible as a thin clear 
zone external to the spicules along the fibre, but 
which is more abundant at the intersection of 
branches. A weak system of secondary fibres is 
present but does not form a coherent reticu- 
lum; the over-all aspect of the skeleton is lax, 
with considerable emphasis on the interstitial 
material, both spicules and calcareous debris. 
Primary fibres range from 90-185/a (135/a) 
in diameter; secondary fibres, 25-100/a (62/a). 
At intervals the dermal membrane is supported 
by radiating spicule brushes, 20-50/a wide, usu- 
ally occurring in groups of 3-5. These are 
united by spongin to the nodes of the dermal 
skeleton. These spicule brushes arise from the 
FIG. 23 Mycale cavernosa n. sp. Sta. 125. Holo- 
type. usnm 23703. 
