NOTES. 
395 
179 The extinct Horse ( Hipparion ) 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 toucl), 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 hoofs, 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 
(Galeopithecus) is considered an Insectivore. 
183 The old term Quadruinana 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. 
188 This feature was shared by the extinct Anoplotheriuvi , 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 w'ould 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 
