phological feature; but I ask, if over and above the details of the conformation of the teeth, fingers, and toes, the tarsus and carpus, above the characters that reflect the exact kind of alimentation, the precise method of locomotion, there is not something more general, answering to special habits, to more or less aërian, terrestrial, aquatic, diurnal, or nocturnal ways of life or abode, which impresses on the totality of the organism that general family resemblance which the naturalist recognizes outside of all those special modes of adaptation, which he studies with so much care to find in it a testimony, an expression, a formula in support of his thought and vision. A particular trait, a progressive variation of form, it is evident, reflects in general the elevated influence to which I allude. The teeth, the condyle of the jaw and its articular cavity, the temporal fosses, express quite exactly the regimen of the animal, and consequently some of its habits. The patagium, of which some traces have been observed among the petaurite marsupials, permits us to establish a series leading to the bats and passing by the galeopitheci. The genealogy of the perissodactyli, one of the most satisfactory that science has determined, rests essentially on a single character, the number and degree of atrophy of the fingers or toes.
But is the chosen form of character all? Has not nature different ways of reaching the same end, and can it not distribute its influence over the whole of the organism without making any of the characteristics particularly distinctive, and even while leaving present seemingly contradictory ones? The mouse is recognized everywhere by its attitude, its walk, its head, and its general shape, and still is found under different names among the aplacental and the placental orders, with the rodents and with the insectivora, terrestrial, half-aquatic, half-flying, and flying. The same is the case with the genus squirrel, which is scattered, with changed names, among several orders, being simply modified in some peculiarity. There is a group of most remarkable leaping animals among the marsupials, which, while preserving its type, is distributed, according as it acquires certain new characters, among various placental orders.
I ask, then, if the peculiar bearings of the monkeys, if their habitat, exclusively in trees among their most pronounced representatives, which impresses a special stamp on the whole individual; if the proportions of their body, the extent and situation of the articular surfaces and the consequent mobility of the segments upon one another, do not furnish a sufficient motive for establishing their relationship with the lemurs, and not with the ungulates? Likewise the lemurs, which lead a similar life, conduct to the marsupials, which also constantly inhabit trees. Between the ungulates and the monkeys I see nothing common of
