87 
a spherical mass of tubuli, arising from a centre, each tubular spine 
being terminated by an expanded conical aperture, and a strong re- 
semblance is at once observed between these bodies and the mode of 
extension in the newer portions of the sponge itself; this fact, to- 
gether with that of the perfect siliceous character of these minute 
bodies, induces me to come to the conclusion that they are not di- 
stinct, free animals, parasites to the sponge, but the gemmules of the 
sponge, in which they are found; and I think their increase, so as 
to become perfect sponges when ejected from the parent mass, can 
be readily understood by comparing their present form with the 
recently formed portions of the sponge. Supposing the gemmule (?) 
to have arrived at that state which commences its individual life, its 
increase would not be by an extension of the tubuli in a straight 
line ; but from the edges of the terminal aperture of each spine other 
and similar tubuli would or might be sent off, and thus the end of 
every spine become a fresh centre and anastomusing point, and in 
this way a very slight addition would give the newly formed mass 
the reticulate and vesicular character of the parent sponge. 
“ Being anxious to identify the peculiar and entire siliceous cha- 
racter of this sponge with its generic appellation, 1 have adopted the 
name of Dactylocalyx; the principal characters of which may be thus 
expressed :— 
“« Sponge fixed, rigid, siliceous ; incurrent canals, uniform in size ; 
excurrent canals large, forming deep sinuosities on the outer surface, 
radiating from the root to the outer circumference. 
“ For the species the name Dactylocalyx pumiceus is proposed.” 
A collection of Birds from Australia, presented by J. Olive, Esq., 
was exhibited. 
