THE PROSIMIANS 



(PROSIMII). 



Climbing animals, with complete dentition, opposable thumb and great-toe, bony orbit not closed behind, mostly 



more than two teats, and a campanulate (diffuse) placenta. 



A singular mixed assemblage of tropical 

 animals, which, in defiance of all anatomical 

 grounds, have always been associated by 

 ignorant animal -stuffers with the apes and 

 monkeys, solely on account of the possession 

 of an opposable hallux or pollex on all four 

 extremities. But it is now known to scientific 

 naturalists that the points of distinction from 

 the monkeys are so important that we must 

 rather rank the Prosimii, or at least some 

 of them, among the lowest mammals, a pro- 

 ceeding to which there is the less reason for 

 holding the existence of the opposable digits 

 in question to be an objection, since such 

 digits are frequently met with fully developed 

 on the hind -limbs even of low forms of 

 marsupials. 



The brain-case is roundish or longish with 

 crests and ridges very little marked, a con- 

 dition connected with the weakness of the 

 jaws and their muscles. Even in those 

 genera in which the eye is very large it lies 

 altogether behind the facial region, which 

 with the bony nose mostly appears to be 

 drawn forwards almost in the form of a tube. 

 The bony orbits are never complete as in the 

 Simite, but are merely surrounded by an 

 external ring (and even that in Galeopithecus 

 is not complete), their cavities being con- 

 tinuous behind with the temporal fossae or 



depressions at the temples. This single 

 decisive character enables us to distinguish 

 at the first glance the skull of one of the 

 Prosimii from one of the Simiae. 



The eyes and the orbits inclosing them 

 are commonly very large, as in most nocturnal 

 animals, and in some, as the loris and tarsier, 

 are so enormous that only a thin plate of 

 bone, as thin as a piece of paper, separates 

 the two orbits, and only a narrow canal is 

 left in the middle line for the passage of the 

 nerves of smell to the nostrils, which are 

 much elongated. In others again, the lemur, 

 the indris, and the aye-aye, the bridge of the 

 nose is broad, and the eyes appear to be 

 placed more to the side as in Carnivora and 

 other mammals. The tear-ducts, which in 

 all the Simile as in man, lie in the inner angle 

 of the orbit, are found in the lemurs, as in 

 most marsupials, outside the orbits on the 

 cheeks. 



The jaws, as already remarked, are mostly 

 weak. In some (Indris, Lemur) the pre- 

 maxilla becomes fused very early with the 

 upper jaw, while in others (Tarsius, Loris, 

 Microcebus) the sutures or lines of union 

 remain visible all through life. The lower 

 jaw is always slender, never high, as in many 

 of the Simla;, and its two halves always 

 remain separated by a suture, which is even 



