816 
DK. J. S. BOWEEBANK ON THE ANATOMY 
The remains of several exhausted ovaria are dispersed over the surface of the membrane, 
a few only retaining their original form and proportions. They do not appear to have 
had a spicular skeleton, but to have consisted of a coriaceous envelope strengthened 
and supported by a reticulated skeleton of apparently keratose structure. They are 
nearly globular, and are firmly cemented to the membrane by a broad basal attachment. 
Although themselves apparently in an effete state, the membrane on which they are 
seated was in a decidedly living and active condition. It is thickly coated with sarcode, 
and abundantly furnished with equi-anchorate spicula. Numerous slender acuate or 
snbspinulate spicula are also dispersed over its surface, which are occasionally fascicu- 
lated after the manner of the first indications of the formation of a Halichondraceous 
skeleton. But the most interesting feature of the membrane is, that at intervals over 
the whole of its surface, and especially at those parts most free from the dispersed 
spicula, there are small detached groups of spicula, each consisting of two or three 
irregular fasciculi crossing each other at various angles, resembling in every respect 
the early stages of development of the gemmules or ova so graphically described by 
Dr. Geant in his account of the gemmules of the sponge he has designated Halichmdria 
panicea. The presence of these early developments of the ova is precisely in accordance 
Avith the discharged and effete condition of the ovaries, and is just such an effect as 
might naturally be expected under such circumstances. Fig. 13, Plate XXXIV. repre- 
sents one of these ovaria seen by a microscopic power of 108 linear ; fig. 14, a small 
piece of the reticulated wall of the ovarium with a power of 308 linear ; and fig. 15 repre- 
sents the development of one of the ova and the surrounding equi-anchorate spicula with 
a power of 108 linear. 
Gemmules. 
If we adopt as a definition that a gemmule is a body not containing ova, but that it 
is a vital mass separated from the parent and capable of being ultimately developed into 
a single individual possessing the same specific characters and capabilities as the parent 
mass, we must consider the reproductive bodies so ably and minutely described by 
Dr. Geant in his paper “ Observations on the Structure and Functions of the Sponge*,” 
not under the designation of ova, but rather under that of gemmules ; and indeed the 
learned author seems to have entertained some doubt of their being correctly designated 
by the former term, as in speaking of them in a subsequent portion of his paper in 
page 14, he says, “ since these germs or so-named ova are, &c. I have therefore been 
induced to arrange them under the designation of Gemmules. 
Dr. Geant describes their first appearance in the sponge in the months of October 
and November “ as opaque yellow spots visible to the naked eye, and without any defi- 
nite form, size, or distribution, excepting that they are most abundant in the deeper 
parts of the sponge and are seldom observable at the surface;” he also states that 
‘‘ they have no cell or capsule, and appear to enlarge by the mere juxtaposition of the 
* Edinburgli New Philosophical Journal, vol. i. p. 16, plate 2, figs. 24-29. 
