1866.] ON THE ANATOMY OF THE CRESTED AGOUTI. 385 



oblong pads, situated at the base of the innermost toes, the smaller 

 one being internal, having at a distance of less than half an inch 

 behind it a trace of a third pad. Beneath the metatarsals there is 

 a good deal of transverse wrinkling, and underneath the digits the 

 same scaly appearance as in the digits of the fore foot (fig. 1, C). 



The Guinea-pig has a hind foot in some respects very like this ; 

 but the pads are comparatively larger, and the external one much 

 the larger of the two ; the three toes also are of nearly equal length 

 (fig.l.D). 



The Hare has four toes, with fur on the sole ; and when the fur is 

 removed neither pads nor wrinkles are to be distinguished. In the 

 length and shape of the sole and toes the Hare's foot approaches that 

 of the Agouti's ; but the number of digits, with the other differences, 

 are marks of the separation between Lepus and the two genera of 

 the HystricidcB. 



Morbid Appearances. 



Those exhibited on opening the visceral cavities were the follow- 

 ing : — Congestion of the lungs, more particularly the lobes of the 

 right one. In both lungs, moreover, were innumerable specks of 

 melanotic deposit, each spot not above the size of a pin's head, but 

 the whole giving to the pulmonary tissue the characteristic appear- 

 ance of incipient melanosis. All the other viscera, as well as the 

 brain, seemed healthy ; but there was a more than natural effusion 

 of serum in the cavity of the abdomen. 



Viscera and Generative Organs. 



A good account of the viscera of Dasyprocta acuschy (Illig.) has 

 already been given by Professor Owen*; and, a few years later 

 (1834), in some notes also read before this Society, Mr. Rymer 

 Jonesf described with considerable minuteness those of Dasyprocta 

 aguti, Illig. A complete redescription may therefore be considered 

 unnecessary. 



Prof. R. Jones mentions that, in the specimen of D. aguti dis- 

 sected by him, the stomach had a remarkable constriction between its 

 cardiac and pyloric orifices, which gave it the appearance of consist- 

 ing of two distinct cavities. Our observation of this viscus in D. 

 cristata agrees with that of Prof. Owen, who found it in D. acuschy 

 altogether simple and without such a contraction. 



The shape and relative position of the intestinal tract in D. cris- 

 tata resembles the description given by these authors of the species 

 dissected by them. But we found in it that the small intestines were 

 about 4 feet shorter than in D. aguti, namely 208 inches in total 

 length. The large intestines, on the other hand, measured 45 inches, 

 being thus almost double the length of the same in D. aguti accord- 

 ing to Prof. Pi. Jones. The caecum also differs from that of D. aguti, 

 being both longer and wider — 10 inches in length, and about 4 inches 

 in circumference. 



* P. Z. S. 1830-31, p. 75. t P. Z. S. 1834, p. 82. 



