ANATOMY OF CACOPUS SYSTOMA. 531 



which presumably are sub-peritoneal fat. These are found in 

 relation to the blood-vascular system and the vertebral column. 

 The auricles and the trunctos arteriosus are thickly covered with 

 fat, and the ventro-auricular groove is filled with the same ; this 

 cardiac fat, it should be observed, is found on the inner layer 

 of the pericardium. Small quantities of fat occur also on the 

 walls of the inferior vena cava, where it opens into the sinus 

 venosus. In close proximity to the vertebral column is situated 

 a longitudinal patch of fat on both sides extending from the 

 fourth vertebra to the ninth, and a small median deposit where 

 the cranium articulates with the atlas. 



Among the other Indian frogs I examined, sub-dermal as well 

 as sub-peritoneal fat in relation with the blood-vascular system 

 was found in Rana hexadactyla, the analogous form in India to 

 Rana esculenta, and in Rana hreviceps, a burrowing species. Never- 

 theless, in these instances, while fat under the skin is confined to 

 the neck-region, even that does not occur so regularly. The 

 same fat in the inguinal region has been noticed by other observers 

 in several species of Bufo (3), Xenopus Icevis, and notably in 

 nemisus guttatum, an American Engystomatid (1) ; in the first - 

 mentioned toad, however, it is ventrally situated, while in the 

 last one there is a complicated development of the same in con- 

 nection with the iliac sac which does not obtain in C. systoina. 



As this. Indian toad has a remarkable habit of burrowing 

 underground when the dry-season commenced and of passing 

 into a torpid state, it struck me that these fat-bodies might have 

 a nutritive value to the animal during that eestivating period. 

 Therefore, in July and August, 1911 and 1912, I obtained by 

 special efibrts a considerable number and examined them. It 

 was found that both the sub-dermal and sub-peritoneal fat-bodies 

 had undergone, in accordance with my expectations, a great 

 redaction in size and a change in colour from yellow to dull white, 

 as compared with specimens examined during the wet-season. 



From the above considerations one may draw the following 

 conclusions : — Fat occurs normally in several places in the body 

 of C. sy stoma, both internally and under the skin. While the 

 pre-renal fat-bodies may be looked upon as feeders to the gonads 

 during the breeding season, the other fat-bodies in this toad may 

 be regarded as assisting in the general nutrition of the body 

 during aestivation. It is noteworthy that in Bufo, Hemisus, and 

 this toad the sub-dermal fat is developed in connection with the 

 lymphatic system. 



4. Discussion on '"'•the stout shape"*' ofQ. systoma. 



A remarkable feature of the two toads of this genus is, as several 

 observers have noted, the rotund shape of the body. This has 

 been, till now, accounted for in various ways. Thus, Glinther (6) 



* Vide figure in Boulenger, G. A. (2), p. 496. 



Proc. Zool. Soc— 1922, No. XXXVII. 37 



