18G2.] OF PITHECIA MONACHUS. 331 



divides posteriorly into two branches, of which the lower is the 

 longer. The collateral sulcus (n), instead of passing downwards and 

 forwards along the inner side of the temporal lobe, turns abruptly 

 outwards, and appears on the outer face, in the rather sharp angle on 

 the inferior border of the hemisphere at the junction of the occipital 

 and temporal lobes. 



The dental formula is, I. g, C. |^, P. g, M. g=36. 



The incisors of both upper and lower jaw project forward, so that 

 their anterior edges form together an angle of 100°. The upper 

 central incisors are of moderate size, and rounded at the edges. The 

 upper lateral incisors are extremely small ; there is a considerable 

 diastema between them and the canines, which are strong and conical, 

 and project downwards and somewhat outwards. The two rows of the 

 upper molar series are perfectly straight and parallel. The premolars 

 increase in size from the first to the third, the first being notably 

 smaller than the others and unicuspidate. The first molar is rather 

 larger than the second ; their crowns are square, nearly flat, but 

 grooved longitudinally in the middle, the raised edge on the outer and 

 inner sides being slightly divided into two tubercles. The crown of 

 the third molar is just beneath the gum. The four lower incisors are 

 long and narrow, of nearly equal size, the outer ones slightly rounded 

 at the corners ; their outting edges form a continuous gently curved 

 line. A very small interval exists between them and the sharply 

 pointed conical canine, which is of very nearly the same size as the 

 upper one. The first premolar is very small ; the two succeeding 

 ones increase in size. The first and second molars are nearly equal, 

 and the third not very markedly inferior. As with the upper series, 

 these teeth are very slightly tuberculated ; they have the appearance 

 of being considerably worn, but, as the animal was so young, this is 

 scarcely probable. There is a carious spot on the posterior part of 

 the third premolar on both sides. 



The length of the tongue, from the base of the epiglottis to the tip, 

 is 1*4 inch ; its breadth '5 inch ; its sides are parallel, the end square, 

 with the corners slightly rounded. The sublingual organ is fleshy, 

 except towards the end, which is sharp-pointed and cleft at the ex- 

 treme tip ; it is free to the extent of '25 inch, and its apex is "3 

 from the tip of the tongue. 



The left lung has two lobes, quite separate from one another, each 

 having a special division of the bronchus ; the right lung is composed 

 of four distinct lobes. The main arterial trunks are given ofi" from 

 the aorta as in man, the innominata dividing into right subclavian and 

 right carotid, and the left carotid and left subclavian coming off se- 

 parately. 



The stomach is simple, its general form nearly globular, but the 

 pyloric portion is lengthened and tubular. The cardiac and pyloric 

 orifices are much approximated. The small intestine, from the py- 

 lorus to the ileo-caecal valve, measures 50 inches ; its diameter is 

 nearly uniform throughout, about '4 inch. Peyer's agminated glands, 

 the largest 1;^ inch long, are scattered at tolerably regular distances 



