Page:Popular Science Monthly Volume 33.djvu/843

Rh the lower primates are simply the beginning of the series, the transition from the other orders to that of the primates, is but a step. The lemurs furnish most of the imperfect primates of which we have spoken. They included or include three groups of animals—the Galeopitheci, the Cheiromys, and the lemurs proper.

The Galeopitheci, or flying-cats, inhabit the Sunda Islands, the Moluccas, and the Philippine Islands. They furnish one of the examples of the difficulty of placing in our classification certain groups qualified with paradoxical characteristics, for the reason that they are transitional groups having some right to be put in several.

The Cheiromys include only one genus, the aye-aye of Madagascar. It resembles the squirrel, but has features also of the ape and the lemur. By dentition it is an insectivore or lemur in infancy and a rodent in adult age. It is evidently a primate at the start, but a species hesitating whether it shall continue a primate or become a rodent.

The lemurs proper are divided into the fossil and the recent. The former appear in the Eocene when there existed parallel with them the marsupials in a declining stage and the first placental mammals—the carnivora, rodents, ungulates, and the insectivora. Europe has furnished five genera of them and America more, the most important among them being the Anaptomorphus, from which Mr. Cope makes man a direct derivative. The recent species are distributed in three geographical groups, the first and most numerous being confined to the island of Madagascar, the second to that island and Africa south of the Sahara, and the third living in the island of Ceylon, the Malacca Peninsula, the Moluccas, and the Philippines, or the regions which Haeckel supposes to constitute the remains of the vast southern continent which he calls lemurian.

The lemurs are tree-dwelling and nocturnal animals. They have four opposable thumbs with the exception of the tarsier, which has only the hind thumbs opposable. All their fingers, as a rule, have nails except the hind forefinger, which has a claw, or in the loris, the fore little finger; but the nails are all badly shaped and seem transitional from claws. A general formula can not be framed for the teeth. The number varies from thirty to thirty-six.

All these facts tend to establish that the lemurs have not a fixed, homogeneous type, but that they constitute a transitional group from animals with claws to animals with nails. They may consequently be regarded as the first or perhaps the second stage (regarding the Cheiromys as the first) toward the better characterized monkeys; but serious objections are brought against this view. One was based by M. Broca on certain features of the