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



In being neckless and devoid of lamina, the malleus of Tupaia much resembles that 

 of some of the lower Primates, especially Midas or Rafale, or certain Lemurs, the 

 shallow articular facets being a Ceboid feature. It cannot be said to resemble the mallei 

 of the Sciurida? so closely ; for though the latter have a similar head, and are neckless, the 

 manubrium is of a different type. 



The incus has a high and narrow body ; the processus brevis is rather long, thin, and 

 pointed, but hardly diverges from the body ; the stapedial cms is scarcely longer than 

 the short process ; it is curved and divergent, and bears a very small Sylvian apophysis. 

 In general characters this bone is very like the same in many Monkeys and Lemurs. The 

 author has never seen the long process so divergent as to form (with the body and 

 short process as the top-piece) a letter T out of the incus, as Hyrtl states of Tupaia 

 javanica. 



The stapes has a very small head and extremely slender, straight crura ; the base is 

 rather narrow. The aperture is filled by a thick bony canal in the recent skeleton, whence 

 this frail ossicle can with difficulty be removed. 



In the Colugo (Galeopithecus volans, PI. LXII. fig. 18) the head of the malleus is much 

 flattened antero-posteriorly, and is produced a little forwards and upwards above the 

 articular area. The surface for articulation with the incus is of the type of Homo and 

 the higher Primates, being narrow vertically and wide laterally ; the outer extremity is 

 placed much higher than the inner ; and the two facets are faintly indicated, the upper 

 Iving rather internal to the lower ; both have a vertical convex ridge internal to the 

 middle line of the whole surface. The neck is very short and- constricted ; and a very 

 narrow lamina (which seems to me to be absorbed in the adult skull, as the processus 

 gracilis is in Man) connects it to the slender processus gracilis. It bears a small tuber- 

 cular processus muscularis on its inner aspect. 



The manubrium forms little more than a right angle with the neck, and is long, broad, 

 flattened laterally, and recurved ; it possesses a distinct trace of a processus brevis. Its 

 outer aspect is distinctly bordered from the sides, but very narrow, and prominently 

 spatulate at the recurved extremity. 



The affinities of the malleus of Galeopithecus are puzzling. At first, judging from its 

 articular surface, narrow neck, and large flattened manubrium, with a trace of a pro- 

 cessus brevis, it seems allied to the highest Primates. But, on the other hand, in the 

 Manis the articular surface is shaped much as in Homo ; and in Galeopithecus the head is 

 flattened, and the narrow lamina and slender processus gracilis connected with it also 

 resemble the corresponding parts in the scaly Edentata ; and the manubrium still more 

 nearly resembles that of the Manis than that of Man, having an outer aspect separated 

 by broad borders from the sides. It approaches the form of the malleus in Lemur more 

 than that of any other of the Lemuridse ; but its head is not so well developed, nor of the 

 form seen in any Lemur or Monkey, and its neck is more constricted and distinct than in 

 any of these animals except the Apes and highest Cercopithecidse. It differs widely from 

 the malleus of the Tarsius, the Nycticebidse, and Galagos ; but it is more like that of 

 GUromys, where the head is better-developed, though the articular surface, neck, and 

 manubrium are very similar. 



