1889. ] FAT-BODIES OF THE SAUROPSIDA. 607 
lie in distinct spaces beneath the skin, separated from the abdominal 
cavity by a stout muscular tract, are not the homologues of the 
subperitoneal fat-bodies of the Monitors, but of subcutaneous fat- 
deposits occurring in the Sauropsida in addition to the subperitoneal 
(cf. p. 609). The fat-bodies of the Crocodiles that correspond to 
those of Lizards are more lateral than is usual in the latter group. 
Thus the membrane that is referred to by Beddard as being 
muscular in the Crocodile, according to the view here expressed 
represents, in the ventral region, a great part of the muscular body- 
wall. 
In the quotations given above the position of the kidneys relatively 
to the so-called “horizontal membrane”? has been referred to. A 
reference to figs. 14 and 15 shows that in Monitor niloticus the 
hinder portion of the kidney projects well into the peritoneal cavity 
which contains the intestines and reproductive glands, and that the 
part in front of this lies as it were in the membrane in question, or 
between its peritoneal and parietal layers ; so that, though the anterior 
portions of the kidneys project outwards into the circumadiposal 
cavities, the membrane referred to does not exactly separate these 
from the reproductive glands. 
But, even if the whole of the kidney were shut out of the general 
intestinal cavity, this would, I think, neither be a point of special 
similarity to the Crocodiles nor have much morphological signifi- 
cance. We find such a condition not only in the Crocodiles but in 
Chelonia (Emys, Testudo). In Snakes (ef. figs. 8, 9, 10), and in 
the Lizards themselves, the extent to which the kidneys project into 
the peritoneal cavity is variable, and the Amphisbzenide are, so far 
as I know, unique in the freedom with which these organs hang 
into the peritoneal cavity. 
In birds, again, the kidneys, as opposed to the reproductive glands, 
are extra-peritoneal in position (cf. figs. 46 and 47 of my paper “On 
the Subdivision of the Body-cavity,’’ Plate XLIX. above, p. 452). 
I think that the preceding points to the conclusion that the 
membrane which in Monitors is seen to cover the abdominal viscera 
when the body-wall is first cut into, must be regarded as the perito- 
neum, backed by the lining membrane of the space into which the fat- 
bodies project—that it, in fact, consists of the peritoneum together 
with another layer belonging to the body-wall. 
With regard to the term “ horizontal’? membrane or septum it 
seems to me that it is used to comprise two things, which may with 
advantage be considered apart. ‘There is, firstly, the membrane, 
referred to above, which divides the circumadiposal and peritoneal 
eavities. To this I would attach no particular morphological impor- 
tance. It appears to me not to divide one part of the body-cavity 
proper from auother, but to be, as Beddard (1, p. 100) seems fully to 
recognize, but a special development of a tract which occurs in other 
Lizards, correlated, as I would say, in Monitors with the greater 
extension of the circumadiposal spaces, In fact, in the separation 
of the membrane under discussion from the body-wail, the Monitors 
seem to be but following what is a line of weakness for Reptiles 
