20 Mr. H. J. Carter on the Subspheroiis Sponges. 



maining at the base of the parent chiefly renovate the old 

 mass — although such is the nature of the sarcode of SpongiJla^ 

 that I think almost any portion of it, on becoming thoroughly 

 soaked, even after drying for a whole hot season, might, under 

 advantageous circumstances, grow into a new individual. 



With such properties, then, the seed-like body seems to be 

 more allied to a bud than anything else, and therefore truly to 

 deserve the name of " gemmule." 



The " ciliated gemmule," first described, by Dr. Grant, and 

 latterly more at length by M. N. Lieberkiihn (Annals, 1856, 

 vol.xvii. p. 407) as the " swarm-spore," I have not yet had an 

 opportunity of seeing either in the fresh- or salt-water sponges. 

 But of its existence there can be no doubt ; and if it had been 

 particularly sought after, probably it would not have escaped 

 my observation. 



I have, however, as will have been seen, described and 

 figured bodies in Tethya arabica (fig. 19, PI. II.) which seem, 

 under the circumstances, to be very much allied to the gem- 

 mules of T. cranium figured by Dr. Johnston. They are 

 of all sizes below 15-6000ths of an inch in diameter, and 

 situated in the fleshy part of the Tethya^ chiefly towards its 

 base, where they, by the aid of a common lens, appear in the 

 form of little white specks scattered plentifully throughout this 

 substance. The white speck, however, is not the whole of 

 this body ; for when it is viewed through the microscope by 

 transmitted light, it is seen not only to be spherical in itself, 

 but also to be surrounded by a spherical transparent capsule, 

 charged with minute bacillary bodies resembling spicules, but 

 not siliceous, I think, although resisting the solvent power of 

 nitric acid applied to them on the slide. They may be albu- 

 minous tubes on which future spicules might be developed, 

 but are too minute for anything but conjecture of this kind. 

 On the other hand, the spherical nucleus or opaque white body 

 itself appears to be composed of album.ino-oleaginous matter, 

 in some instances assuming the form of minute globular masses, 

 but for the most part so consolidated by first the drying and 

 then, latterly, the soaking in spirit and water of the sponge 

 for elementary examination, that hardly more can be satisfac- 

 torily stated of it than that its contents ajpjpear to be albumino- 

 oleaginous, and that these had a minute globular structure. 



Still there are these bodies scattered in great abundance 

 through the fleshy portion of the sponge; and they seem to get 

 their capsule developed in proportion to their size, so that at 

 an early period they would be nothing but white albuminous 

 "spherules. 



I have not been able to find anything like them in Tethya 



