NOTES. 395 



179 The extinct Horse (Hipparlon) had three toes, two small hoofs dangling 

 behind. The foot of the Horse is of wonderful structure. The bones are 

 constructed and placed with a view to speed, lightness, and strength, and 

 bound together by ligaments of marvellous tenacity. There are elastic pads 

 and cartilages to prevent jarring ; and all the parts are covered by a living 

 membrane which is exquisitely sensitive, and endows the foot with the sense 

 of toucli, without which the animal could not be sure-footed. The hoof 

 itself is a world of wonders, being made of parallel fibres, each a tube com- 

 posed of thousands of minute cells, the tubular form giving strength. There 

 are three parts, "wall," "sole," and "frog" the triangular, elastic piece 

 in the middle, which acts as a cushion to prevent concussion and also 

 slipping. 



180 The Camel and Llama are exceptional, having two upper incisors and 

 canines, are not strictly cloven-footed, having pads rather than hoofc, and 

 are hornless. 



. 181 The Hyena alone of the "Carnivores has only four toes on all the limbs, 

 and the Dog has four hind-toes. The Lion is the king of beasts in majesty, 

 but not in strength. Five men can easily hold down a Lion, while it re- 

 quires nine to control a Tiger. 



182 The eye-orbits of the Lemurs are open behind. The Flying Lemur 

 (Galeojrithecus) is considered an Insectivore. 



183 The old term Quadrumana is rejected because it misleads, for Apes, as 

 well as Men, have two feet and two hands. There is as much anatomical 

 difference between the feet and hands of an Ape as between the feet and 

 hands of Man. Owen, however, with Cuvier, considers the Apes truly "four- 

 handed." 



184 It fails to cover in the Howling Monkey and Siamang Gibbon ; but in 

 the Squirrel Monkey it more than covers, overlapping more than in Man. 

 As to the convolutions, there is every grade, from the almost smooth brain 

 of the Marmoset to that of the Chimpanzee or Orang, which falls but little 

 below Man's. 



185 The tailed Apes of the Old World have longer legs than arms, and 

 generally have " cheek- pouches," which serve as pockets for the temporary 

 stowage of food. 



186 In the human infant, the sole naturally turns inward ; and the arms 

 of the embryo are longer than the legs. 



187 The Aye-aye, the lowest of the Lemurs, is remarkable for the large 

 proportion of the cranium to the face. 



168 This feature was shared by the extinct Anoplotherium, and now to 

 some extent by one of the Lemurs (Tarsius). 



189 We have treated Man zoologically only. His place in Nature is a 

 wider question than his position in Zoology ; but it involves metaphysical 

 and psychological considerations which do not belong here. 



190 See Lewes's charming "Studies in Animal Life." Doubtless an ex- 

 amination of all the strata of the earth's crust would disclose forms im- 

 mensely outnumbering all those at present known. And even had we every 

 fossil, we would have but a fraction of the whole, for many deposits have 

 been so altered by heat that all traces have been wiped out. Animal life is 



