318 Mr. Yarrell's Notes on Comparative Anatomy, 



the same oblique direction in both jaws as in the Chinchilla, but the 

 enamel in Lacjostomus is flatter on the crowns, being perhaps only the 

 effect of age and consequent greater attrition. The nearest described 

 genus to this animal appears to be Lagostomus. 



Agouti. [^Dasyprocta Acuti, 111.] 

 Length from the nose to the root of the tail 17| inches. Stomach 

 capacious but having a single cavity. Small intestines 18 feet in length; 

 the ccecum 8 inches; the large intestines 2 feet 9 inches. The length of 

 the intestinal canal is to the body of the animal as 1 4^ to 1 ; the small 

 intestines are to the large as 5 to 1 ; the form and volume of the ccecum 

 resembles that of our common species of the genus Cohaya. 



Porpoise or Porpus. [Delphinus Phocana, Briss.] 



The whole length from the snout to the centre of the tail 4 feet 6 inches. 

 The upper half of the body of a lead coloured black, the under part sil- 

 very white. Skin possessing all the tough and flexible feel of well-dressed 

 leather. On separating the lower surface of the mouth from the plates 

 of the under jaw by cutting in the direction of their inner edges, the 

 apparatus which closes the trachea, formed by an extension of the 

 arytenoid cartilages and epiglottis, was immediately brought into view ; 

 the most anterior portion when pressed upwards completely closed the 

 oesophagus, and the orifice of this elongated larynx could be readily 

 brought into contact wth the aperture in the palate leading to the blow- 

 hole, the valves and air cavities of which were examined in situ, and 

 afterwards dissected out for preservation ; the larynx, trachea and bron- 

 chial tubes were also removed entire to be preserved. Lungs large, 

 consisting of one single lobe of uniform size on each side, dense in struc- 

 ture, pierced with numerous air tubes arising from the bronchice, which 

 penetrate deep into the substance of the lobes ; these air tubes at their 

 extremities contained numerous worms about 4 inches long, slender and 

 white. The heart presented nothing remarkable. CEsophagus capable 

 of considerable distension, opening into a stomach of four cavities; the 

 first of them hned with a villous coat, the second having a honey-comb 

 surface, the third and fourth plicated; the whole being very similar to the 

 well-known divisions and appearance of the compound stomach of rumi' 



