70 PROFESSOR OWEN ON THE AYE-AYE. 



The olfactory nerves commence by a broad white tract (e) from the outer and under 

 part of the sylvian fissure, from which it can be traced to the corpus striatum, and by 

 a low grey protuberance (i) near the back and lower part of the hemispheric fissure. 

 The nerve is closely connected with the under part of the anterior lobe to near its 

 terminal expansion (c), which does not extend beyond the anterior lobes of the 

 cerebrum. 



The corpus striatum (PI. XXIV. fig. 5, s) is 11 lines in length, and has its anterior 

 larger rounded end closely fitting the fore part of the ventricle, which is not prolonged 

 into a horn-shaped bend beyond it. A broad choroid plexus covered the taenia semi- 

 circularis dividing the corpus striatum from the thalamus (l), beyond the outer and back 

 part of which the ventricle extended about a line backward, and then was continued with 

 the great hippocampus downward. The posterior indent (fig. 5, i) is the beginning 

 of that extension which forms the " scrobiculus loco cornu posterioris" of Tiedemann', 

 in higher Quadrumana. There was no crenation on the convex border of the hippo- 

 campus, nor any digital eminence. In other particulars of cerebral structure and in 

 the disposition of the cerebral nerves Chiromys closely agrees with Stenops. 



There is a delicate tapetum at the back of the cavity of the eyeball. The axis of the 

 lens is one-third its transverse diameter. 



§ 7. Digestive System. 



The Mouth. — The characters of this aperture, and of the lips, jaws, and teeth, have 

 been already described. The symphysis of the jaw, united by ligament only, and for a 

 limited extent, permits a slight divaricating movement of the rami with their large incisors; 

 much less, however, than that in the Phalangers or Kangaroos. On the palate (PI. XXIV. 

 fig. 6), anteriorly, are three transverse ridges, slightly convex forward, progressively 

 increasing in breadth, followed by four transverse pairs of ridges, curving more 

 obliquely backward as they approach the pharynx. The tongue (PI. XXIV. figs. 7, 8, 9) 

 is rather narrow,' deep, slightly expanding anteriorly, and rounded at the tip, without 

 an intermolar rising. The free portion is short, thick, fleshy, obtuse ; it projects, in 

 the passive state, three lines beyond the apex (ib. figs. 8 & 9, «) of the sublingual plate (6). 

 This body is flat, triangular or leaf-shaped, the free apex (a) very short : a filamentary 

 longitudinal ridge, or lytta, of cartilaginous firmness, projects from the middle of the 

 under surface. A iiarrow free fold of membrane (c) is continued backward from each 

 side of the base of the sublingual plate to the corresponding side of the pharynx. On 

 the dorsum of the tongue (fig. 7) the tactile papillae are short, subobtuse, rather large 

 for the size of the tongue, becoming larger near the fauces. About one inch and a half 

 from the apex of the tongue are a pair of fossulate papillae, about two lines apart. 



The soft palate is a broad and deep fold overarching the root of the tongue in front 

 of the epiglottis. The uvula is represented by a short and narrow median longitudinal 



' ' Icones Cerebri Simiarum, &c,' Folio. 1S21. 



