1890.] HELODERMA SUSPECTUM. 193 



vpe have just said. In the submedian, longitudinal plane it con- 

 stitutes the umbilical ligament, and this double fold of membrane 

 partially divides the coelom into right and left halves. Of unusual 

 size, the corpora adiposa here lie between the internal muscular 

 parietes and the peritoneal layers, while the kidneys are external to 

 the latter, the reproductive glands internal to it, the two being 

 separated by the horizontal portion of this membrane. Following 

 the peritoneum to its attachments we find it to be fast all along the 

 spinal column, while ventrally it is firmly attached mesio-longitu- 

 dinally to the muscular wall of the ccelom. The parietal layer 

 also makes fast to the tendino-fascial divisions, here and there, that 

 indicate the lines of insertions of the digitations of the principal 

 body-wall muscles. Other than this, both the visceral and parietal 

 layers of the peritoneum in this Lizard are but loosely attached to 

 the parts they cover, and may by gentle traction be easily detached. 

 Thoracic and abdominal cavities are partitioned from each other by 

 the usual reflection of this membrane, while below the liver the 

 large anterior abdominal vein is seen to be borne in the ventro- 

 parietal layer. Continued as the umbilical ligament, it passes 

 between the lobes of the liver as a single layer, which in our present 

 subject bears the ramifications of a large vein. 



Beddard has called the visceral layer of the peritoneum, as it 

 occurs in certain Lizards, the "horizontal membrane;" and this author, 

 in a masterly paper upon this subject (P. Z. S. 1888, p. 99), has said 

 that "In Monitor there is some little difference (from Iguana and 

 Lacertd) ; when the body-walls are cut open and reflected, the ali- 

 mentary viscera are not exposed as they are in Iguana. A loose mem- 

 brane covers these viscera ; the membrane looks as if it were simply 

 the lining peritoneum of the abdominal cavity which had got sepa- 

 rated and detached from the abdominal parietes ; this is, however, not 

 the case ; an examination by the aid of the microscope showed clearly 

 that a layer of peritoneum covers the abdominal musculature, aud 

 is quite distinct from the horizontal membrane ; in Varanus griseus 

 the peritoneal layer was particularly distinct, for the reason that it 

 contained numerous pigmented corpuscles. For the greater part 

 this membrane is free from the ventral parietes ; anteriorly it is 

 attached to the median ventral line ; dorsally it is attached along 

 the spinal column ; here and there it is also attached to the lateral 

 parietes by membranous bands. It passes over the lobes of the 

 liver and the stomach, and shuts off the lungs from the abdominal 

 cavity. The umbilical ligament dividing the two liver-lobes is pre- 

 sent as in Iguana, and is attached to the dorsal side of the horizontal 

 membrane. This horizontal membrane also separates the kidneys 

 from the reproductive glands ; the latter lie internally to it ; the 

 kidneys are placed outside it. The ventral surface of this membrane 

 bears a vein of some size, the anterior abdominal vein. The fat- 

 body, when present, lies below the membrane, and is therefore shut 

 off from the abdominal cavity." In many forms, and Beddard 

 gives us a list of some of them {Lacerta, Urotnastix, Cgclodus, 

 Iguana, and others), this horizontal membrane is for the greater 



