LIEBERKUHN, ON SPONGILL^. 
219 
served not unfrequently great numbers of moving corpusclse 
in sponges whicli had been torn up^ which could be readily 
distinguished from them. They had_, for instance,, a far 
longer and thicker filament^ and a much smaller head. They 
" swarm usually in numbers together, with the heads in 
contact, and in their motions closely resemble the well-known 
spermatozoa. They arise from spherical receptacles, sur- 
rounded with a structureless transparent tunic, around which 
are disposed the sponge- cells. These receptacles are about 
-Y2 mm. in diameter. The author was unable to prove their 
nature to be that of spermatozoa, and all his endeavours to 
witness their penetration into the pore of the gemmule, as a 
kind of micropyle, were bestowed in vain. 
The peculiar bodies described by Carter, under the same 
name, are considered by the author to bear no resemblance 
to those noticed by himself, inasmuch as they are much 
larger and have a contractile head. He has noticed bodies 
in the course of the winter, corresponding with Mr. Carter's 
figures, but these he regarded as larger or smaller specimens 
of Trachelius trichophorus. But it is otherwise, he observes, 
with respect to the corpuscles described by Huxley, in 
Tethyum, as spermatozoids ; these, he says, strikingly re- 
semble those of the Spongillce, 
