206 



QUAD11UMANA. 



the three small muscles for the little finger 

 on the opposite edge of the hand. The con- 

 sequence of all^his is, that the hand of the 

 monkeys of the Old World approaches to the 

 perfection of the human hand, from which it 

 differs by the length and the narrowness of the 

 palm of the hand, the length of the fingers, 

 the backward position of the imperfect thumb, 

 and a less variety of movements. For the 

 physiological results which can be derived 

 from this difference, I refer to my Reck. d'Anat. 

 comp. sur le Chimpanse, p. 34. The muscles 

 of the posterior extremities differ more from 

 those of the human subject. The glutcsi are 

 feeble, and inserted very low on the femur; 

 the gracilis is much broader than in man, and 

 inserted very low in the tibia ; the same is 

 the case with the semitendinosus, the semi- 

 membranosus, and the biceps femoris. The 

 result of this low insertion must be, that the 

 knee can only be maintained in a bent, and 

 consequently the trunk in a semi-erect at- 

 titude. 



The gastrocnemius and solceus remain sepa- 

 rate until their insertion in the calcaneum, 

 where they unite to form one tendon. They 

 are flatter than in man, and consequently do 

 not form the calf of the leg, which is so cha- 

 racteristic in man. 



There is a plantaris, as in man. The 

 monkeys seem to be the only brute animals 

 which possess it. 



The flexor magnus of the great toe or 

 thumb of the posterior extremities is not 

 confined to this toe, but gives tendons to the 

 other toes. Consequently it combines its 

 action with that of the flexor magnus 4 digit, 

 pedis. The monkeys possess also a flexor 

 brevis, lumbricales, an abductor and adductor 

 hallucis, a flexor brevis, adductor brevis digiti 

 minimi, peronceus longus and brevis, and 

 tibia/is posticus. All the muscles on the sole 

 of the foot are more isolated than in man, and 

 consequently they produce more distinct and 

 separate movements for the digits, and prin- 

 cipally for the hinder thumb. 



They have no perontBus tertius, but the 

 tibialis anticus differs from the same in man, by 

 its separation into two fascicles, of which the 

 inner seems to act as a tibialis anticus, while 

 the outer is a long abductor hallucis. I found 

 this disposition in all the monkeys I had the 

 opportunity to dissect, and it is also confirmed 

 by the observations of E. BURDACH. 



The last myological peculiarity which I 

 shall mention is, that the tendon of the ex- 

 tensor communis longus quatuor digitorum is 

 surrounded and fixed by a ligamentous loop, 

 about which I can add* the historical pecu- 

 liarity, that this ligament, hitherto unknown, 

 has been described in the same year, and per- 

 haps in the same month, by A. Retzius in 

 Stockholm, and by myself in Amsterdam. * 



* A. Retzius, Bemerk. neb. ein Schleuderformiges 

 Band in dem Sinus tarsi des Menschen u. mehrere 

 Thiere in J. Muller, Arch. Berlin, Jahrg. 1841, Th. 

 v. p. 497. W. Vrolik, Rech. d'Anat. Comp. sur le 

 Chimpanse', p. 22. tab. v. fig. 2. 



NEUROLOGY. The brain of the monkeys 

 of the Old World represents an imperfect 

 outline of the brain of man. By the form 

 and the number of convolutions, LEU RET * 

 proved that it approaches to the brain of the 

 human subject ; but however great this analogy 

 may be, there remains, however, no doubt that 

 there are some typical differences between 

 the brain of man and of the monkeys, and that 

 from the Chimpanzee to the Cynocepliali, the 

 gradual tendency to inferiority is as manifest 

 as in the other points of organisation. We 

 still want perfect representations of the brain 

 of the first, but we may supply this defect by 

 drawings of the brain of the Orang-cetan, of 

 which TIEDEMANN has represented the basis, 

 SANDIFORT the superior surface, and I a ver- 

 tical section. (Figs. 125, 126, 127.) If we 



'Fig. 125. 



Basis of the brain of the Orang-cetan. 

 (After Tiedemann.} 



Flg.\26. 



Superior surface of the brain of the Orang-cetan. 

 (After Sandifort.} 



* F. Leuret, Anat. Comp. du Systeme nerveux 

 considere dans ses rapports avec 1'intelligence. Paris, 

 1839, 8vo. 



