Elements of the Spongida. 357 



only of the species ; but whether this is accidental or indica- 

 tive of a dioecious nature I cannot saj ; and, after all, it maj 

 be nothing but the "' glarj bodies " of Chondrosia tinged with 

 the dje (Hyde's violet ink) of the preparation. 



It would not be right to leave this subject without referring 

 to the additional elements of reproduction in the freshwater 

 sponges which have been called " genimules." 



I need not enter now into the structure of these so-called 

 " seed-like bodies," nor the development of the sponge from 

 them, as this has been done elsewhere, but would, en passant^ 

 observe that while Lieberkiihn was chiefly engaged with the 

 ovular development of Spongilla from the River Spree in 

 1856 at Berlin, I was almost exclusively engaged with that 

 of the gemmule at Bombay, simply because I never, to my 

 knowledge, saw an ovum in any stage in any Bombay Spon- 

 gt'Ua, although I often sought for it, being desirous of seeing 

 the swarm-spore or embryo so satisfactorily described and 

 delineated by Lieberkiihn. 



As regards the origin of the gemmule, no more is known 

 than of that of the ovum in the marine sponges. All that I 

 can state of it from actual observation in the living sponge 

 was published long ago, viz. in 1849, and nothing of this 

 kind, I believe, has been done since. It is as follows : — " At 

 the earliest period of development in which I have recognized 

 the seed-like body it has been composed of a number of cells 

 united together in a globular or ovoid mass (according to the 

 species) by an intercellular substance similar to that just 

 described [' mucilaginous']. In this state, apparently with- 

 out any capsule and about half the size of the fully-developed 

 seed-like body, it seems to lie free in a cavity formed by a 

 condensation of the common structure of the sponge immedi- 

 ately surrounding it. The cells of which it is now composed 

 appear to differ only from those of the fully-developed sponge- 

 cell in being smaller, in the colourless state of their germs, 

 and in the absence of hyaline vesicles ; in all other respects 

 they closely resemble the sponge-cells, possessing also a like 

 but more limited power of motion " (' Annals,' 1849, vol. iv. 

 p. 87). These cells and those composing the " condensation 

 of the common structure of the sponge " were not illustrated 

 till 1856 {tb. vol. xviii. pi. vi. figs. 41 and 42), when all that 

 is stated of them that is of consequence here is in the " Explan- 

 ation of the Plates" {tb. p. 245), viz. as follows : — 



" Fig. 41. Ovibearing sponge-cell, still polymorphic, from 

 the seed- like body at an early period, viz. before the capsule 

 is formed. Spherical form 1- 700th inch in diameter." 



Ann, & Mag. !<f. Hist. Ser. 5. Vol. xix. 25 



