R. W. H. ROW—REPORT ON THE SPONGES : NON-CALCAREA. 369 
HETERONEMA ERECTA, Keller. 
Synonymy :— 
1889. Heteronema erecta, Keller (18). 
1906. Heteronema erecta, Topsent (35). 
A single specimen has been identified as this species, though only after 
considerable hesitation. Keller (18) does not state whether the flagellated 
chambers of his genus Heteronema are eurypylous or diplodal, but only gives 
measurements for the chambers. However, he puts his sponge into the 
Spongeliidee, in which the chambers are eurypylous, as the family is now 
understood. My specimen, however, possesses diplodal chambers, and on 
that account I have removed the genus Heteronema from the Spongeliidee to 
the Spongiidee. 
(The specimen has been cut into three slices, but they can easily be fitted 
together.) 
The specimen consists of a group of conical protuberances of somewhat 
irregular shape, growing upright from a small base. The specimen measures 
125 mm. long, 60 mm. to 70 mm. wide, and 65 mm. to 75 mm. high at 
different points. 
The surface is regularly covered with minute conuli, which average 0:3 mm. 
in height and are 1:0 mm. to 1°5 mm. apart. These indicate the ends of the 
primary fibres of the skeleton. They are connected by series of ridges 
radiating between the conull. 
The oscula are fairly numerous, and measure 2 mm. to 8 mm. in diameter. 
The pores were not seen on most of the sponge, but in some parts they could 
be distinguished in the meshes between the ridges connecting the conuli. 
The colour is black-brown on the outside of the sponge and a dark brown 
inside. 
The texture is firm, hard, and incompressible. 
The skeleton consists of a coarse but regular reticulation of spongin-fibre, 
filled with foreign bodies, chiefly sand-grains, and can be differentiated into 
primary and secondary fibres. The primary fibres run radially, and the 
secondary fibres form a rectangular meshwork with them. 
The whole skeleton is exactly like that described by Keller, as is also the 
canal-system, save that Keller omits to state whether the chambers of his 
species are diplodal or eurystomous. In the specimen now under considera- 
tion they are diplodal and measure 0°03 mm. to 0:038 mm. in diameter. 
Locality. Sherm Sheikh. 
Distribution. Red Sea, Gulf of Aden. 
DurRIELLA, n. gen, (PI. 41. fig. 29.) 
Spongiidee in which the skeleton is composed of an irregular reticulation of 
spongin-fibre, which forms iax trellis-like groups of fibres instead of simple 
fibres. 
29% 
