SUMMARY 167 



being less complex as the life and habits of the animal become 

 simpler. The most complex problem which a monkey's sense 

 of touch will have to solve will hardly go beyond the need to 

 distinguish between the size and kind of surface of such fruits 

 and nuts and other articles of food as it may require ; there 

 can be no such interpretation of details and careful estimation 

 and comparison of surfaces as man's organs of touch are concerned 

 with. And so down the scale of Mammals this use of the tactile 

 sense must become simpler imtil it becomes limited to the 

 discrimination of the very few kinds of surface which enter into 

 its humble Hfe. It may even be that this use entirely vanishes 

 in the lowest groups and is replaced by sensations of pain alone. 



(2) It is other\vise with the second use, viz., the maintenance of 

 equihbrium. This reflex act is common to all mammals and in 

 most of them the tactile sense of the hand and foot, and in birds 

 the tactile sense of the foot is of the utmost importance to them. 

 It is probably more highly developed in the arboreal animals and 

 especially those that are nocturnal also than in any others. At 

 any rate the illustrations of the skin-structures of the group of 

 Lemuroids given in Figs. 12G, 127, 128, 129 suggests very strongly 

 that they are more than any group endowed with a high degree 

 of this reflex power of maintaining equihbrium. The marked 

 development of the papillae of the corium in this group, has been 

 sufiiciently considered before, and no further description is 

 required here. The well-known Slow Loris {Nycticehus tardi- 

 gradus) may be taken as a t}T3ical and marked example of these 

 Lemuroids. Its habits are most instructive from the present 

 point of view. It is an animal of about the size of a cat and of 

 strictly nocturnal and arboreal habits. In the daytime it will 

 sleep in the hollows of trees curled up into a ball, and at night- 

 time it coEomences its more active Ufe, chmbing along the branches 

 of trees in search of its prey, such as fruits, birds, insects, eggs. 

 Its method of chmbing and moving along the branches has been 

 carefully observed, and in Lyddekker's "Natural History" the 

 following account is given. 



" He is extraordinarily slow in his motions and his trivial name, 

 Eardigradus, well marks his habit in that particular. When he 



