388 MR. A. H. G. DORAN ON THE MORPHOLOGY 



body (strictly expressed, on the antero-superior aspect), and does not lean outwards, as 

 described in Ateles, and as found more or less in all the Cebidse and Hapalidse. More- 

 over this surface is in Nycticebus very saddle-shaped, indeed almost convex. The pos- 

 terior crus is stout, short, and slightly divergent ; the stapedial cms is stout, straight, 

 long, and very divergent, supporting an " os orbiculare " or Sylvian apophysis, which is 

 small as in all Lemurs. 



The stapes has slender crura, not very divergent ; the base is rather thick and almost 

 plane. I have never found any intercrural bony canal in any skull of Nycticebus, Arcto- 

 cebus, Loris, and Perodicticus. 



In a malleus of N javanicus the articular surface is deeper cut than in N. tardigradus. 

 The characters of the ossicula of Loris gracilis are almost identical with those of 

 Nycticebus ; only the head of the malleus is even still shorter vertically, and the anterior 

 part of the body of the incus projects forwards somewhat as in Galago. In Arctocebm 

 calabarensis (PL LVIII. fig. 27) the extreme characters of the neckless malleus are even 

 better-marked than in Loris; the head of the malleus is shorter than in any of 

 the Platyrrhine monkeys, and the articular surface is far deeper cut than even in 

 Hapale. 



Perodicticus potto (PL LVIII. fig. 25) resembles Nycticebus in its malleus and 

 stapes ; but the incus is higher than broad, its articular surface being, however, similar 

 in position to the same in the tardigrade Loris. 



In Tarsius spectrum (PL LVIII. fig. 28 *) the malleus, which is quite neckless, has a 

 head of square outline, not nearly so compressed vertically as in the last family, and 

 projecting considerably forwards. The articular surface is deep, and rather wide ; the 

 manubrium is slender, ending in a spatulate extremity ; there is a trace of a processus 

 brevis ; and the tensor tympani is inserted into the inner border of the manubrium midway 

 between the tip and the root. The incus has a square body ; both crura diverge con- 

 siderably. The stapes is small, even in proportion to the size of the animal ; its crura 

 are very thick, and its base almost plane. 



Whilst the characters of the ossicula of the aberrant Tarsius are somewhat negative, 

 the sole representative of the Chiromyidse presents very salient features in its ear- 

 bones. 



All the ossicula of the Aye-aye (Chiromys madagascariensis, PL LVIII. fig. 29) are 

 much larger in proportion to the size of the animal than in any tailed monkey. The mallei 

 in the College collection are larger than any from Ateles, and as large as that ossicle in 

 Cynocephalus. The head is much flattened vertically ; its upper free surface is broad 

 and concave, far more developed than in the other Lemures. The articular surface is 

 deeply cut and wide vertically ; the two facets are well-marked : the upper is very wide, 

 and the lower is very small. There is a distinct short neck, twisted, together with the 

 head, somewhat inwards ; the manubrium is long, rather narrow laterally at the base, 

 and forms a similar curve and angle to what is seen in the anthropoid apes. There is a 

 small angle corresponding to the processus brevis, and a distinct processus muscularis 



* Taken from a new-born Tarsius. The remark made in the foot-note to the description of Propithecus applies 

 to this as well. 



