SPONGER FROM THE ABEOLHOS ISLANDS. 513 
are also narrow meandering grooves, covered in life by the thin dermal 
membrane. Colour in spirit purplish brown in parts, lighter brown in others; 
texture compact and compressible, resilient, but tough. 
There is a thin but well-developed cortex of sand and broken spicules ; this 
cortex is usually of a minutely reticulate nature, the meshes being about 
0'13 mm. in diameter and containing inhalant pore-areas. In other parts the 
cortex seems continuous. 
The skeleton consists of primary fibres about 0"05 mm. in diameter, running 
vertically to the surface and containing much foreign matter (broken spicules); 
the secondary connecting fibres, which average about 0'02 mm. in diameter, 
form a close network with somewhat irregular, polygonal meshes about 
0*2 mm. wide. 
There is a very well developed collenchymatous ectosome, in which lie 
large subdermal cavities. The canal system resembles closely that of 
Eiispongia. Some of the larger canals in the choanosome are surrounded by 
a thick layer of collenchyma. The flagellate chambers are small, subspherical, 
and about 0'03 mm. in diameter; they are either eurypylous or with very short 
canaliculi, and closely packed together. The mesogloea between them is very 
finely granular. Embryos are present, some in an advanced state of 
development. 
Hyatt [1877] described two sponges, Sponyelia incerta and Spongelia 
spinosa, which Lendenfeld [18S9] makes synonymous with his Coscinoderma 
pyriforme. We can find nothing in Hyatt's description to justifj- this. 
Register Nos. and Localities. II. 7 a, III. 7, Wooded Isle ; VI. 20 a, VI. 22, 
Sandy Isle. 
48 a. Coscinoderma pyriforme Lendenfeld, var. /3. 
Coicinoderma pyriforme Lendenfeld [1889]. 
The single specimen, which measures 25 mm. in greatest height, 55 mm. 
in greatest width, and has an average thickness of 10 mm., is a flattened, 
cup-shaped sponge with irregular but entire margin ; it has probably been 
attached to a rock at several points on its convex lower surface. Colour in 
spirit dark brown on the upper surface, greyish brown on the lower ; texture 
fine, compact, compressible. 
The upper surface is very minutely conulose, subglabrous, and has a well- 
marked but thin, minutely reticulate cortex made up mostljr of broken spicules. 
Inhalant pore-areas lie in the meshes of the cortex. There are no visible oscula 
on this surface. The lower surface is smooth and has a thin, continuous 
cortex formed of broken spicules, no inhalant pore-areas being visible ; a 
number of closed oscula are scattered over this surface, surrounded by 
radiating subdermal exhalant canals. 
The skeleton arrangement and the structure of the soft tissues agree closely 
with those of Coscinoderma pyriforme var. a. A large number of small, 
LINN. JOURN, ZOOLOGY, VOL. XXXV, 37 
