PERITONEUM OF MAMMALIA. 503 



ib. o, with the spleen. In the Kangaroo it is of moderate size, 

 continued loosely from the stomach to the transverse colon, but 

 not extended beyond that part. The posterior layer lies be- 

 tween the stomach and the intestines, and exemplifies one of the 

 uses of the epiploon, as it prevents these parts from inter- 

 fering with each other's motions. The anterior layer generally 

 contains more or less fat. In the Petaurus the epiploon is 

 continued from the great curvature, of the stomach and the 

 commencement of the duodenum. In the Phalangers it is of 

 considerable extent and is usually loaded with fat. In the 

 Opossums I have found it generally devoid of fat, when this 

 substance has been accumulated in other parts. In the Phasco- 

 gales and Dasyures the epiploon is of moderate size, and contains 

 little or no fat. The epiploon is attached to the lower arches 

 of the several divisions of the stomach in Cetacea, is always 

 devoid of fat, and is of limited extent : the subdivided spleens, 

 fig. 355, h, i, are scattered in it, as in a net : it is in parts reticu- 

 late. The epiploon is small and does not cover the intestines in 

 Sirenia, Proboscidia, and Peris sodacty la. It is, also, of limited 

 extent in the Hog-tribe. In fatted Sheep it is larger and is reti- 

 culated with adipose matter. It is attached, in Ruminants, to the 

 right side of the left division of the rumen, and along its anterior 

 or ventral convexity, passing from the right of this to the abomasus 

 and the beginning of the duodenum: it does not cover the intestines, 

 and is commonly found crumpled up beneath the paunch. The 

 reticulate structure of the great omentum appears to be natural 

 and pretty constant in the Dog and some other Carnivora : in the 

 Seal the omental fold is thin and devoid of fat. 



The peritoneum lining the elastic ventral wall of the abdomen in 

 the Elephant and Rhinoceros is of unusual thickness and strength, 

 the areolar tissue connecting it to adjacent structures presents an 

 aponeurotic firmness : the free surface of the serous membrane I 

 found to be white and opaque: 1 it is generally transparent and 

 opaline or colourless. In some hibernating Rodents a fold of peri- 

 toneum extends forward from each lumbar region, covering the 

 lateral convolutions of the intestine as far as the umbilicus, and 

 towards the beginning of winter becoming the seat of an abdominal 

 deposit of fat : they may serve with the ordinary omentum the 

 double purpose of nonconductors of heat and a store of nutriment. 



[Since Sheets t-dd were printed off, the excellent Paper clxxxvi" has appeared, 

 showing that the deciduous teeth of the mole, though too minute to seem of use, 

 are not shed until after birth. In other respects Mr. Spence Bate confirms the 

 talpine formula given at p. 304.] 



1 v". p. 37. 



