351 
to our Knowledge of the Spongida. 
viz. three divergent smooth arms, each ending in three 
smooth prongs, nearly on the same plane, one of which is 
central and in a line with the arm, and the other two lateral, 
viz. one on each side divergent, l-150th to l-90th inch long by 
l-225th inch across the head (PI. XXIX. figs. 1,2), subject 
to great variation in size and form of the terminal elements in 
the same and different specimens; 2, small, consisting of a 
short shaft, similar in form to the last, with a similar develop¬ 
ment at one end, but with only three undivided arms at the other 
end (fig. 3, h ), all except the shaft minutely spined and 
showing the central canal very plainly, l-600th inch in 
diameter across the large head (figs. 3, 3 a) ; 3, flesh-spicule 
minute, bihamate {fibula), C- and S-shaped, microspined, 
1-3000th inch in diameter (figs. 4, 4 a). No. 1 is the largest 
and staple form, no. 2 smaller and less plentiful, no. 3 very 
abundant. Size of specimen varying with the size of the 
excavation of the Cliona. 
Hab. Marine, in cavities of old stony coral excavated by a 
Cliona. 
Loc. West Indies and Australia, in Millepora alcicornis ; 
and in old Stylaster sanguineus , South Seas. 
Obs. Examined in the dried state. Wherever I have found 
this sponge it has been in the said excavations in company 
with Cliona mucronata , Sollas ( c Annals,’ 1878, vol. i. p. 54), 
but separate. Hence, as Cliona is the only excavating sponge 
with which I am acquainted, I conclude that Samus anonyma 
is not a Cliona. The filaments that are appended to the little 
masses of dried sarcode appear to be portions of the latter, 
which originally occupied the finer passages of the Cliona , 
drawn out by the contraction of the mass now occupying the 
excavated chamber. The specimen from Australia, to which 
I have alluded, was in the late Dr. Bowerbank’s collection 
now in the British Museum; it bears my running no. 699, 
and came from a box of specimens labelled by Dr. Bower- 
bank “ From Mr. Ingall, Australia.” 
Heretofore I have found a spiculation like that of Dercitus 
niger , Cart .,=Battersbya Bucklandi , Bk., in the cavities of 
Cliona mucronata , as indicated by the presence of the latter 
with it, in old coral from the island of Cuba; and having often 
observed this black sponge ( D . niger) here, at Budleigh-Sal- 
terton, growing into the minute crevices of the red rock, it 
seems, from its gummy sarcode and confused spiculation, to 
be not only allied to Samus , but to the Gumminida also. 
No. 2 spicule (PI. XXIX. fig. 3) is very like that of a Corti- 
cium Annals,’ ser. 4, vol. xii. p. 19, pi. i. fig. 5, &c.). But, 
be this as it may, the “ large spicule ” was first figured by 
