CHAP. IV] THE GENERAL ANATOMY OF THE TARSII 97 



as in that Amphibian, the anatomical conformation of the hind 

 limbs is greatly specialized. This is most marked perhaps in the 

 muscles of the thigh. Again in the proportions of the respective 

 toes, a close resemblance obtains between Tarsius and the arboreal 

 frog Phyllomedusa. Abel 1 has admirably discussed the significance 

 of the elongated tarsal bones (to which Tarsius owes its scientific 

 name) and has pointed out the morphological differences between 

 Tarsius and other saltatory mammals (ex. gr. Macropus). It 

 will suffice to note here that Tarsius has acquired the requisite 

 modifications and proportions of the hind-limbs without sacrificing 

 the prehensile function of the foot, and it is still to some extent 

 plantigrade. (In the Frog, the provision for swimming had to 

 be safeguarded.) In most saltatory mammals such functions have 

 been waived, and the necessary elongation is provided through the 

 metatarsal bones rather than the tarsus. Among the Lemurs 

 certain forms, ex.gr. the Galagos, are also saltatory, and in these 

 the changes, which have reached their climax in Tarsius, are seen 

 in a less advanced stage. 



The tail of Tarsius is long and (in some cases at least) it is 

 provided with a terminal tuft recalling that of the Jerboa (Dipus). 

 The tail probably fulfils an important function in preserving 

 equipoise during the rapid movements of the animal, and I think 

 that the presence of a cutaneous patch (with grooves) found on the 

 ventral aspect, suggests some development of a prehensile function 

 also. 



Yet another striking peculiarity is seen in the curious spatulate 

 digits : these are irresistibly reminiscent of the corresponding 

 parts in the Gecko, though in detail very different. 



B. The Hair 2 . (1) As in Lemur, the " sinus " hairs or vibrissae 

 will be considered first. They include three main groups, viz. the 

 supra-orbital, naso-labial, and malar or cheek series, but the pig- 

 mented pads (from which the hairs project in Lemurs) are either 

 absent or indistinct. The vibrissae at the wrist of the Lemur 

 are not recognized by Schwalbe, save in the form of a transient 

 embryonic elevation on the part concerned. The eye-lashes arise 

 from the surface of the eyelid, not from its margin. This point is 



1 Palaeobiologie, 1912. Also Mivart, The Frog, 1881, p. 93. 

 - Schwalbe : op. cit. supra, for reference, see p. 65. 



I), m. 7 



