72 



an oblong rounded form, nearly as large as hazel-nuts. The right, as 

 usual, was closely attached to the vena cava inferior, and both were 

 siluated mesiad of tlie upper extreinities of the kidneys. The above 

 structure of kidney and large size of the supra-renal glands appear 

 to be common to all the Glires that have been hitherto examined. 



" The liings were divided into three lobes on the left side and four 

 on the right, the additional lobe or lobulus impar occupying the usual 

 situation between the pericardium and diaphragm ; having the cesopha- 

 gus behind and the vena cava inferior in front of it. 



'•The heart was more pointed at the apex than in \.\\e Acouchy , and 

 the great vessels vvere given ofi from the arch of the aorta in a difle- 

 rent manner; the left subciavian arising separately, the right sub- 

 clavian and carotids by a common trunk : in the Rat these ves- 

 sels arise as in Man. Nothing unusual was observed in the 

 structure of the heart, but the coagulated fibrine in the cavities 

 was firmer, and adiiered more strongly to the parietės than ordi- 

 nary. This organ had evidently been in a statė of inflammation, for 

 the pericardium had contracted an adhesion to the base of the right 

 ventricle, and the serous covering of that cavity was thickened and 

 opake. The contour of both auricles was rounded and entire ; there 

 being a great similarity between them, as in the Cavies. The blood 

 returned from the head and anteriorextremities, was emptied into the 

 right auricle by a single vein. In the Rat, Porcupine, Elephant, and 

 in all the Marsvpiata that I have examined, viz. Macropus, Phalan- 

 gista, Phascolomys, Pliascolarctos, and Perameles, there are tvvo di- 

 stinct superior cava; entering the auricle, as in Birds and Reptiles. In 

 the Hog the left azygos vein enters the auricle near the inferior caca ; 

 being previously joined by the coronary vein. 



"The thymns gland is about the size of a pea, of a red colour, 

 and of a firm fleshy texture. 



" The transverse section of the trachea is somewhat triangular, the 

 cartilages forming the tvvo anterior sides, and a small part of the pos- 

 terior; but gradually encroaching upon that side towards the termi- 

 nation of the tube, where their estremities are occasionally bifid. The 

 bronchine ąuickly lose their cartilaginous structure after having en- 

 tered the lungs : they had been in a statė of acute inflammation at 

 the tirae of death. 



" The thyroid gland is proportionally larger in this than in any 

 other quadruped I have dissected ; it is composed of two lateral 

 lobes, each 10 lines in length, from 3 to 4 lines in breadth, and 

 from 2 to 3 in thickness : these lobes are joined by a distinct 

 band, 2 lines in breadth, passing obliquely between their lo\ver ex- 

 tremities across the third, fourth, and fifth rings of the trachea. When 

 these dimensionsare compared vvith those of the animal itself, it will 

 be seen that this gland, in proportional magnitude, is even greater 

 than iu the human subject. Its structure was lobulated, and appa- 

 rently healthy. 



" The thyroid cartihige is of a rounded form, bulging out at the 

 lower part, and is larger in proportion to the cricoid than in ihtAcouchy. 



