26 Wortman — Studies of Eocene Mammalia in the 



and over, hanging on their tails, licking them on the head and 

 face. I must add, however, that now and again he gave them 

 a sharp bite, and then bounded off, full of fun at the noise 

 they made in consequence of the sly nip he had inflicted. This 

 active trickery he never appeared to tire of ; and I was myself 

 so pleased on witnessing the droll antics of the creature that 

 the night passed and it was near daybreak before I put a stop 

 to his frolics by catching and consigning him to his cage. In 

 bounding about on the level ground, his jumps, on the hind- 

 legs only, are very astonishing, at least several feet at a spring, 

 and with a rapidity that requires the utmost attention to follow. 

 From the back of a chair he sprang, with the greatest ease, on 

 to the table, four feet distance." 



The other species of Galago, as well as those of the Mada- 

 gascar Cheirogaleas, also exhibit much activity, and have the 

 power of leaping great distances in proportion to their gen- 

 erally diminutive size. Duncan says of the Senegal Galago 

 f Galago senegalensis) :* "It pursues Beetles, Sphinges, and 

 Moths with great ardour, even while they are on the wing, 

 making prodigious bounds at them, and often leaping right 

 upwards, to seize them. Should it by chance miss its object and 

 accidentally fall from the branch to the ground, it re-ascends 

 with the rapidity of flight to renew the hunt." 



Tarsias is also a powerful leaper for so small an animal, and 

 although not larger than a small common squirrel is said to 

 make prodigious springs, both in the branches of the trees and 

 on the ground, in pursuit of its prey. 



Among many other groups of Mammalia, the leaping habit 

 is by no means uncommon, and as a result important structural 

 changes in the limbs are to be met with. In all such cases, 

 however, if any modification of the hind limbs takes place in 

 response to this mode of progression, it is almost without excep- 

 tion the metatarsus alone that is affected. Thus, among those 

 forms of Kodentia in which the saltatory habit is most highly 

 developed, as the Jerboas, the Cape Jumping Hare, and others, 

 the metatarsals are greatly elongated and modified. The same 

 is true of the characteristic leapers among the marsupials, as 

 exemplified by the kangaroos and their allies. The develop- 

 ment of this habit in certain of the Primates, however, has 

 affected, not the metatarsals, but the tarsals, and the elongation 

 is found in the calcaneum and navicular. This arrangement is 

 unique among the Mammalia, and occurs in no other group of 

 the Vertebrata except the Batrachia, notably the tree-frogs, as 

 was long ago pointed out by Huxley. \ 



The cause for this modification of the tarsal bones to the 



*Loc. cit., p. 238. 



f The Anatomy of Vertebrated Animals, 1872, p. 389. 



