604 MR. G. W. BUTLER ON THE [DeC. 3, 



The extent to which these fat-bodies project into the body-cavity 

 varies, and that in a manner not merely dependent upon their size, 

 but also, so to speak, upon the ease with which the peritoneum 

 separates from the body-wall. In such a Lizard as Tupinamhis 

 teguexin I have seen the fat-bodies projecting forwards into the 

 peritoneal cavity as two yellow lobes, as large as the liver-lobes ; and 

 this may be seen usually to a lesser degree in the common Green 

 Lizard and in others. On the other hand, in a specimen of Gerrho- 

 saurus flavigularis examined, these fat-bodies extend forwards into 

 two spaces ventral to the peritoneum, without any free bulge into 

 the body-cavity. 



A series of transverse sections taken through an Amphisbcena 

 darwinii {ef. figs. 4-7), or a dissection of the animal, show that 

 while anteriorly to the umbilical region the fat-bodies bulge into the 

 body-cavity, in the more posterior region the peritoneum is simply 

 displaced inwards. Thus we have here the two conditions above 

 referred to displayed in different parts of the same animal ; and this 

 is true, in a less striking manner, of other Lizards {cf. figs. 11 & 12), 

 in which the hinder portions of the fat-bodies are obviously quite 

 outside the peritoneal cavity. 



The typical condition of these fat-bodies seems to be that of 

 distinct lobed or festooned masses, suspended in distinct cavities ' 

 lined with smooth membrane, which are no part of the ordinary 

 peritoneal cavity. 



It seems to me that to the extension of these cavities, which 

 surround the fat-bodies, outside the peritoneum, so as to carry it 

 away from the body-walls, we must attribute the peculiar state of 

 things in Monitors, described by Beddard : (1) Proc. Zool. Soc. 1888, 

 pp. 98-107 ; (2) Anatomischer Anzeiger, 1888, pp. 204-206. 



In the Monitors these two cavities communicate anteriorly, so 

 as to form a single horseshoe-shaped cavity, with its free ends 



the alimeutary caual into the subatance of the fat-bodies, aud regarding tliese 

 and the liver simply as store-houses of combustible food-material, one is struck 

 by the remarkable fore-and-aft symmetry displayed by the liver at one end of 

 the trunk and the fat-bodies at the other, in tlieir relations to the adjacent 

 organs. And in this connection one is induced to comment upon the condition 

 of the liver in Siphonops anmdatus as described by Wiedersheim ' Die Anatomie 

 der Gymnophioueu,' p. 74, fig. 82) : — " Die Leber stelt ein lauges, bandartiges 

 in zahlreiches Lappen zerfallendes Organ dar. Die eiuzelnen Lappen entsteheu 

 durch tiefe circulare Einschnitte, liegeu sohoUenartig aufgereiht unt meistens 

 in dichter gegeuseitiger Beriihrung.'' The "Lappen" are in Epicriuin "mehr 

 gelblich gefiirbt," wlule in S. anmdatus they possess " eine mehr graugriine 

 Farbung." 



Again, it may be worth while to note here the fate of the liver in Petromyson 

 {cf. Schneider, ' Beitrage z. verg. An at. und Entwick. d. Wirbel,,' Berlin, 1879, 

 pp. 93, 94) ; EoUeston (' Forms of Animal Life ') says, "At the metamorphosis 

 the tubular structure is lost ; fat appears in the cells ; the gall-bladder and bile- 

 duct are absorbed." 



It must be remembered, however, that (as described in this paper) the fat- 

 bodies in some Eeptiles project but sUghtly or not at all into the peritoneal 

 cavity. 



' It may be sometimes, however, hard to trace distinct spaces round these 

 bodies. 



