94? Mr. H. J. Carter on the Freshwater Sponges of Bombmj. 



rior of the cell, securely enclosed in a globular transparent cavity 

 resembling a hyaline vesicle, but much larger (Plate IV. fig. 5) ; 

 it then attached itself to the upper part of this cavity, assumed a 

 globular form, became opake and motionless, and the larger pro- 

 tean took on its course. 



Such are a few of the habits evinced by the sponge-cell, deve- 

 loped in its natural way and by the process I have mentioned. 



Now, although no doubt may exist in the mind of the reader 

 as to the identity of the sponge-cells developed in the natural 

 way, and most of those developed from the contents of the seed- 

 like body when forcibly expelled ; yet it may be a question with 

 him, whether all the proteans developed by the latter method 

 come from the contents of the seed-like body, and therefore whe- 

 ther the proteans whose habits I have just been describing, which 

 slightly differ from those of the sponge-cell, taken from its natu- 

 ral structure (only so far as this, however, that I have not seen 

 the like evinced by the latter), have not been developed from 

 some other source. 



All that I can say in answer to this question is, that although 

 the proteans, which have evinced the remarkable habits I have 

 described, are larger than the sponge-cell, more active in their 

 component parts, more active as a whole, and appear to possess a 

 greater share of intelligence ; yet their general aspect and com- 

 ponent parts being the same, their constant appearance in the 

 watch-glass with the other polymorphic cells in the progress of the 

 development of the contents of the seed-like body after forcible 

 expulsion, when they are nearly as numerous as any other form 

 of the protean cells then present, together with the fact, that the 

 sponge-cell itself frequently contains pieces of confervse within 

 duplicatures of its cell- wall, and other foreign matters, just as 

 these proteans include within the duplicatures of their cell-walls 

 the objects I have mentioned, leaves me no conclusion to come 

 to so reasonably, as, that the proteans or polymorphic cells so 

 developed are but a higher condition of the sponge-cell met with 

 in situ. How they obtain this condition, whether it be from the 

 peculiar circumstances under which they are developed, or whe- 

 ther it be the development peculiar to a particular class of cells 

 of the same animal, are queries for future inquiry to determine. 



Next to the development of the fleshy substance comes that 

 of the horny skeleton and its spicula, of which little more has 

 been made known to me by my observations, than has been pub- 

 lished by others who have already directed their attention to the 

 same subjects. I have not had time to continue my investigation 

 beyond the development of the fleshy substance, which is the 

 utmost to which the contents of the seed-like body when forcibly 



