232 Mr. H.J. Carter on the Orgajiizatiun of Infusoria. 



is, that one of these granules, which at first hardly appears to 

 differ from the ovule itself, except in size and the addition, 

 perhaps, of a single cilium, may frequently be seen to exhibit 

 movements about a large ovule indicative of a desire to become 

 incorporated with it ; and frequently, also, it seems to succeed 

 in fixing itself permanently to its circumference, before the eye ; 

 while occasionally a monociliated granule may be seen to be ap- 

 pended to one of the sponge-cells thus newly developed, in the 

 same manner that the " zoosperm " attaches itself to similar cells 

 in the old sponge (fig. 43). 



In the absence, then, of direct evidence respecting the ulti- 

 mate destination of these bodies, we must infer that they are 

 germs, which grow into new individuals (perhaps like micro- 

 gonidia*), or that they are impregnating agents, which enter 

 into the ovules, and thus render them capable of further deve- 

 lopment, or both. Analogy, in connexion with the facts men- 

 tioned, seems to favour the latter view ; for when we observe the 

 development of the ovules, and these spheroidal or discoid seg- 

 ments of the granulated nucleus, which are of about the same dia- 

 meter as the ovules, occurring together in the same Euglypha ; 

 and one cell, viz. that of the ovule, remaining entire, while the 

 contents of the other, viz. the spheroidal segment of the nucleus, 

 has apparently divided up into a number of locomotive granules, 

 — the process so far accords with what takes place in higher or- 

 ganic developments during the process of true generation that 

 we become much induced to extend the analogy still further, 

 and consider that the contents of some of the spermatozoid gra- 

 nules or smaller cells go into this larger one to complete it, in 

 the families of Rhizopoda, &c. mentioned. The monociliated cells 

 {" zoosperms '* f) of Spongilla might, perhaps, by some be con- 

 sidered young sponge-cells, which lose their cilium on further 

 development ; for such is the course with the monads which are 

 produced from the rhizopodous cells of the protoplasm of the 



ovules do not appear in this state. It is only when the buds of the fer- 

 ment-cells are very small, that there is any direct resemblance between 

 them and the sponge-ovules presenting a similar condition. If the granule 

 in connexion with the sponge-ovule be a bud, it must be detached from the 

 ' parent when very young, for there are no intermediate stages as in the fer- 

 ment-cell to show that it is in reality one. 



Again, the oscillation of the granule round the sponge-ovule may be a 

 physical attraction ; this oscillation, however, does not present itself among 

 the ferment-cells, while in the sponge-ovule it appears to end frequently in 

 a permanent attachment of the granule to the ovule, — a condition that may 

 be aided by the '* external layer " or {ha])hane envelope of the latter. 



* See Braun on the reproduction of Hydrodictyon. Ray Soc. Pub. Bot. 

 and Phys. Mems. pp. 89 & 261. 



t Ann. and Mag. Nat. Hist. vol. xiv. p. 334. 



