760 
DE. J. S. BOWEEBANK ON THE ANATOMY 
cells exists in the envelope of the ovaries * of Spongilla Carteri, the species described 
by Caeter in his “ Account of the Freshwater Sponges in the Island of Bombay,” 
which that author believed to be Sjpongilla friahilis, Lamarck, but which proves to be a 
distinct species, which I have named after its discoverer, as a slight recognition of the 
good services he has rendered to science by his excellent and accurate observations. 
These cells may be detected in situ after the envelope of the ovary has been sub- 
mitted for a very short time to the action of hot nitric acid, so as to render the coriaceous 
envelope semitransparent without destroying it. The structure of its walls is then seen 
to consist of linear series of cells, closely .packed together in lines of six or eight in 
each, radiating from the centre of the ovary to its external surface. They do not appear 
to be absolutely in contact with each other, but are usually seen to be separated by a 
thin stratum of a transparent substance, probably an indurated membrane or sarcode. At 
the surface of the envelope they frequently appear to be somewhat hexagonal from mutual 
compression. I could not detect a nucleus in any of them (Plate XXVIII. tig. 16). 
Carter and other writers on Sjpongilla have designated the granulated forms of the 
sarcode in those sponges, “ Sponge cells,” but I cannot coincide with that opinion. I 
have frequently tried in vain to detect a proper coat of cellular tissue on the Amoeba- 
like granular masses into which Spongilla flumatilis resolves itself at certain periods of its 
existence, and neither in a healthy and active condition, nor in a state of partial decom- 
position, have I ever been able to satisfy myself of the existence of a surrounding mem- 
brane. It appears to me that these bodies are the result of a natural resolution of the 
sarcode into granular masses of various sizes, each of which, on being liberated from the 
parent body, becomes an independent gemmule, which is capable of reproducing the 
species of sponge from which it emanates. And I have long suspected that the Amoebae 
found in ponds and rivers, and also in sea-water, are not in reality distinct species of 
animals, but that they are free portions of the sarcode of various species of Spongiadae. 
Sarcode {Physical Character) 
is a pellucid, semitransparent gelatinoid substance, variable in colour and insoluble in 
water. It dries readily, and its physical characters are restored by immersion in water with 
little or no apparent alteration. It is usually spread thinly and rather evenly over the 
internal tissues, but the surface is rarely perfectly smooth ; sometimes it abounds in obtuse 
elevations, and occasionally separates naturally into innumerable irregularly round or oval 
masses which are exceedingly variable in size. When examined by transmitted light 
with a microscopic power of 400 or 500 linear, it is always found to contain innumerable 
minute molecules of apparently extraneous animal or vegetable matter, the molecules 
being always more or less in a shrivelled or collapsed condition, and very variable in size. 
Occasionally it is found abundantly furnished with lenticular nucleated cells, nearly 
uniform in size, and often highly coloured. Fig. I, Plate XXIX. represents a portion of 
* These bodies have hitherto been termed Gemmules. For their characters as ovaries I must beg to refer 
the reader to the section of this paper on Eeproduction. 
