GENERAL CHARACTERISTICS. 



79 



Simiae. The brain resembles that of the 

 Insectivora. 



Just as Httle does the structure of the rest 

 of the skeleton correspond to that of the 

 Simla;. The cervical, dorsal, and lumbar 

 portions of the vertebral column (that is, the 

 portion in front of the ribs, the portion bearing 

 the ribs, and the portion behind the ribs) are 

 those of a mammal climbing on all-fours; the 

 narrow pelvis connected with a sacrum of 

 only a few vertebree does not resemble that 

 of the Simiae. 



Although all the prosimians are climbers, 

 yet the structure of the limbs exhibits great 

 diversities. In the aye-aye and the lemurs 

 the upper -arm is as long as the fore-arm, in 

 the others somewhat shorter, in the Gala^o 

 quite short, and in this last, as in the aye-aye, 

 it is stout and massive, while it is in other 

 cases long and cylindrical. The femur or 

 thigh-bone is always long, often longer than the 

 tibia; in the fore-arm, radius and ulna display 

 great varieties of structure. In many forms, 

 as in Galago and Tarsius, the chief bones of 

 the ankle (the scaphoid and calcaneum) are 

 greatly elongated. The digits and nails or 

 claws exhibit multiform variations. Galeopi- 

 thecus has sharp claws on all the digits and 

 neither hallux nor poUex opposable. The 

 aye-aye has flat nails only on hallux and 

 pollex, on the other digits claws, and only the 

 hallux is opposable. In all there is a claw at 

 least upon the second digit of the hind-foot, 

 and in Tarsius the toes expand, as in the 

 tree-frogs, into discs, on which there are 

 small rudimentary flat nails. 



As there is no likeness to the brain of the 

 Simiae in the smooth brain of the Prosimii, 

 so also do the other organs of the latter fail 

 to present the slightest resemblance to the 

 corresponding organs of the former. None 

 of the Prosimii has a human-like ear, this 

 organ being sometimes small, but covered 

 with hair and pointed, sometimes naked, but 

 in that case very large and capable of being 

 rolled up as in the Chiroptera (Bats). The 



uterus is bicornuate (two-horned), some- 

 times even quite divided. Besides the pec- 

 toral teats, found in all animals which carry 

 their young clinging to their breast, there 

 are mostly others also, situated on the abdo- 

 men or even in the region of the groin. 

 Usually the whole body, with the exception 

 of the point of the nose, is covered with 

 hair; the fur is mostly thick and woolly. 

 As in the sloths, the vessels of the thicfh and 

 the upper-arm, the arteries and veins in the 

 region of the groin and axilla break up into 

 plexuses of small vessels, so called rctia 

 juirabilia, which afterwards unite again into 

 common trunks. 



It would lead us too far if I were now 

 to go into a number of other details of 

 anatomical structure, which all serve to show, 

 on the one hand, the fundamental difference 

 of the Prosimii from the Simise, and, on the 

 other hand, the distinctions prevailing be- 

 tween the different families of the Prosimii. 

 Further investiofations will without doubt 

 afford us the means of breaking up this 

 manifestly unnatural order into its separate 

 constituents. 



But I may draw attention to one other 

 essential point. Great weight has justly been 

 attached to the form of the placenta, although 

 it is going too far to regard it, as some do, as 

 the most important character for the classifi- 

 cation of mammals. The Simla; have, like 

 man, a discoidal placenta, which is some- 

 times entire, sometimes divided; but the 

 Prosimii which have thus far been examined 

 (Propithecus, Lepidilemur, Hapalemur, Chi- 

 rogaleus) possess a placenta composed of 

 separate villi, which covers the whole egg 

 except the apical pole, and the form of 

 which, campanulate, as it is called, allies 

 it on the one side to the zonary or belt- 

 shaped placenta of the Carnivora and on the 

 other to the diffuse placenta of the Ungulata. 

 This latter relation especially has great sig- 

 nificance, as the fossil remains of Prosimii 

 prove. Unfortunately these investigations 



