CHAP. IV] THE GENERAL ANATOMY OF THE TARSII 95 



The literature on the anatomy of Tarsius is not scanty, but 

 it is somewhat scattered. My descriptions are based principally 

 on the examination of specimens in the Cambridge Collection : 

 but I freely admit the guidance of such writers as Burmeister 1 , 

 and Professors Elliot Smith 2 , Leche 3 , Ruge 4 , and Schlaginhaufen 5 . 



A. External characters. The principal characters of Tarsius 

 have been enumerated in an earlier chapter (p. 47). In revising 

 the list so far as external appearance is concerned, the small size of 

 the animal, and its disproportionately large eyes (Fig. 52), first 

 claim attention. The face is short and flattened in contrast 

 with those of Lemurs, and it is almost certain that the visual 

 fields overlap so far as to provide " stereoscopic " vision. The 

 curious manner in which the head is capable of rotation is shewn 

 in the illustration. This bird-like habit was noted in the first 

 description of a living Tarsius. Inspection of a mounted skeleton 

 of Tarsius reveals little in the cervical vertebrae that is obviously 

 suggestive of this faculty 6 ; moreover it is not entirely unknown 

 among human beings, though of course anomalous among these. 

 Physiologically, it makes provision for a wide visual survey, and it 

 is remarkable that movements of the head as a whole, rather 

 than lateral movements of the eyeballs, should be conspicuous. 

 Probably the inertia of the large eyes is involved in this. Food 

 is seized with the fore-limbs and thus conveyed to the mouth 

 (Cheiromys 7 does the same, while the true Lemurs tend to seize 

 food in their jaws, though the limbs may be employed as well). 



Though of arboreal habits, Tarsius is none the less a saltatory 

 animal. In a sense, indeed, Tarsius may be said to have acquired 

 the erect attitude ; certainly it has adopted a bipedal mode of 

 locomotion. In its leaps, Tarsius strangely resembles a Frog, and 



1 Burmeister, Beschreibung der Gattung Tarsius, 1846. This monograph is of 

 classical value: the descriptions are admirable, and the author's illustrations are 

 noteworthy both for their accuracy and their high artistic value. 



2 Linnaean Transactions, Vol. vin. Part 10, 1903. Presidential Address, 

 Section H, British Association, 1912. 



3 Leche, Klassen und Ordnungen, Lieferungen 54 — 56, 1899. 



4 Ruge, Morphologischt s Jahrbuch, Band xxix. 1902. 



5 Schlaginhaufen, Morphologisches Jahrbuch, Band xxxn. 1905. 



6 v. infra however for peculiar characters of these vertebrae. 



7 Auctore, Professor Elliot Smith. 



