REPOET ON THE TETRACTINELLIDA. 
97 
echinoicles are those of a Geodinid ; and if proper to the organism, they prove that it is a 
young Geodine sponge. I have seen many young Geodias, but never one quite like this ; 
there is, however, just so much resemblance as would lead me to conjecture that Haeckel’s 
figure (pi. ii. fig. 128, loc. cit.) is a bold but unsuccessful attempt to restore a badly 
prepared section, were it not that with the figure before my eyes I can scarcely conceive 
this possible. 
In my paper on Thenea ivallichii, I was not able to say precisely whether the flagel- 
lated chambers of that sponge are eurypylous or aphodal. This is remarked upon by 
Vosmaer {loc. cit., xxvi. p. 5, sep. copy). Considering that Vosmaer, writing subsequently, 
contributes nothing further to our knowledge of the canal system, beyond the suggestion 
— ^which I need not characterise — that the sponge appears to be too full of holes to afford 
room for flagellated chambers (!), his comments on the intelligibility of my descriptions 
and the finish of my drawings seem somewhat uncalled for. The illustrations represent 
in faithful outline — they are camera lucida tracings — ^just what I could see in the 
sponge and no more ; my sections were not perfect enough to enable me to state 
positively whether the chambers were each provided with an aphodus, or whether 
they opened several together into a common canal ; but I observed the wide mouths 
by which the communication is effected, and with my present knowledge should have 
inferred their eurypylous character. At that time I was less familiar with flagellated 
chambers, but even now, with vastly better prepared slices, I cannot state as a 
matter of positive observation the exact manner of their communication with the 
excurrent canals ; I infer that they are eurypylous from analogy with Thenea wyvilli, 
but taking into account the’ excessive development of collenchyme, I should not be 
greatly surprised to learn that I am mistaken. A section through the ectosome and part 
of the choanosome of Thenea muricata is shown in PI. VII. fig. 3. 
Thenea intermedia, n. sp. (PI. VII. fig. 4). 
Thenea muricata, Bwk. [pars), Vosmaer, Spong. “Willem Barents” Exped., p. 5, 1885. 
Sponge. — Similar in general characters and composition of the skeleton to Thenea 
muricata; distinguished by larger flagellated chambers, obviously eurypylous, and by 
comparative deficiency of collenchyme. 
Habitat. — Mediterranean. 
Remarks. — As the distinction of Thenea schmidtii depends on our knowledge of 
the specific characters of Thenea muricata, I prepared fresh slices of Norwegian examples 
of this sponge, and of specimens from the Mediterranean, which Vosmaer has identified 
with it. If the characters of the soft parts have that value in classification which I have 
assigned to them — and this can only be determined after an examination of a large 
(ZOOL. CHALL. EXP. — PART LXIII. — 1887.) Err 13 
