with some Remarks on the Nature of the Spongise Marinee. 375 



the cells or pores of the Sponge. This opinion is, I think, worthy of addi- 

 tional investigation, because to the exterior of the shells of the seedlike bodies 

 certain fibres or tubules are often appended. 



In pursuing the same inquiry, the following is another supposition which 

 has occurred to me ; that the seedlike bodies are the sporidia, and the germ- 

 like bodies the sporules of the River Sponge, because I found that on opening 

 the seedlike bodies the soft white opake substance with which they are filled, 

 when spread out and submitted to a great power of the microscope, consists 

 of numerous granules interspersed among a somewhat transparent jelly*. 

 These granules are round or egg-shaped, exceedingly minute, and quite dia- 

 phanous, except as to a spot, which is evidently a particle of the same jelly. 

 And as the seedlike bodies themselves are fixed within the cells of the Sponge, 

 they ought strictly to be considered as the seed-vessels or sporidia, and the 

 granules contained within them as the seeds or sporules. Also, since the 

 sporidia when apparently full grown have an orifice at their upper extremity 

 whereby the gelatinous substance and granules escape, the latter, if identical 

 with the germlike bodies, pursuing their way through the water that fills the 

 passages or canals formed by the fibrous network of the Sponge, emerge and 

 swim or glide about by means of their locomotive power, until they have at- 

 tained sufficient maturity, and have procured for themselves a safe lodge- 

 ment ; they then begin to germinate and vegetate by degrees. However, I 

 need scarcely observe to you, that further experiments are necessary to deter- 

 mine which of these two suppositions is the true one, that is to say, whether 

 the locomotive germlike bodies ultimately become identical with the fixed 

 seedlike bodies, or whether the former are the real sporules, and the latter 

 the sporidia ; yet I may add, that I am most strongly inclined to the latter. 



Again, having before remarked that the only traces from whence I could 

 at all infer the animal nature of the River Sponge were its locomotive spo- 



decaying or breaking of parts of the Sponge itself; or by many other causes. They then, attaching 

 themselves to whatever suitable substance they may happen to fall upon, quickly germinate. 



* Professor Link has observed the same sort of substance and granules (seminules) in the similar 

 seedlike bodies (sporanges) of the Spongilla lacustris. He has described them thus : " Lorsqu'on 

 6crase ces conceptacles de graines et qu'on les regarde avec un grossissement trfes fort, on voit les 

 seminules plong6es dans une masse qui est molle tant qu'elle estfraiche." (Annales des Sciences Natu- 

 relles, Seconde S6rie, torn. ii. p. 328.) 



VOL. XVIII. 3 D 



