Darwin made easy / by Edward B. Aveling.

  • Edward Aveling
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Darwin made easy / by Edward B. Aveling. Source: Wellcome Collection.

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    the body. Thus in the Chimpanzee, Orang and Gorilla, the hands, feet and face are bare. And in man the process of hair-vanishing has extended more or less completely from the hands to the arms, from the feet to the legs, from the face to the neck, and from all these to the trunk of the animal. 3. Height.—Pace by pace with the assumption of the erect posture, advances the increase in the length or height of the Primates. The Lemuridse, the marmoset, the spider-monkey, are not longer than 3 feet. The Cynomorpha have a length, that is very generally a height, of about 4 feet. In the lowest of the anthropoids a reversion seems to occur. The Gibbon is usually some 3 feet in height. But after this genus the transition in height is interesting. The average stature of the Orang is some 4 feet 6 inches ; of the Chimpanzee 5 feet; of the Gorilla from 5 feet to 5 feet 6 inches; of the higher races of man from 5J feet to 6 feet. 4. The Teeth.—Once again, for generals, the reference is pp. 8 and 9 of “The Origin of Man.” The particular facts as to the teeth will now be given and will have to do, for the most part, with their number. To understand them, it is necessary to remind the student of the nature and the number of teeth in the human skull. Consider one jaw only—say the upper. Its fellow—say the lower—is almost its identical counterpart. Starting from the middle line just under the partition between the two nostrils and working to one side—say the right—we find (1) two chisel-like teeth, useful for cutting into the food, and hence called incisors (incido = I cut into); (2) one sharp- pointed tooth, very useless to civilised man, but of a type much more frequent in purely flesh-eating animals called canine (canis — a dog); (3) two more massive teeth (I am always speaking of the adult jaw), whose free parts or crowns have two eminences or cusps, and thus give the teeth the name of bicuspids; (4) three yet more massive teeth, each with four or five cusps, the molars (molea =* a mill) that crush the food as millstones crush grain. The two teeth on each side mentioned under (3) are known by another name than that of bicuspids. As they are in front of the molars, and as they, like these, crush or “mill ” the food, the com- parative anatomist calls them pre-molar. Qenoe there are in each half of each jaw 8 teeth—in all
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