32 PBOFESSOB OWEN" ON THE CHA.BACTEES, ETC. 



grade is nearer in form to the flipper of the Seal than is the more 

 perfect digitigrade, retractile-clawed, long and narrow hind foot of 

 the feline quadruped, which is the highest and most typical of the 

 Carnivora. 



The next perfection which is superinduced upon the unguiculate 

 limb is such a modification in the size, shape, position, and direction 

 of the innermost digit, that it can be opposed, as a thumb, to the other 

 digits, thus constituting what is properly termed a ' hand.' Those 

 TJnguiculates which have both fore and hind limbs so modified, or 

 at least the hind limbs, form the order Quadrumana. They have 

 -^ incisors*, and ^ broad tuberculate molars f; perfect clavicles, 

 pectoral mammae, vesicular and prostatic glands, a simple or slightly 

 bifid uterus, and a discoid, sometimes double, placenta J. The 

 Quadrumana have a well-marked threefold geographical as well as 

 structural division. The Strepsirhines are those with curved or 

 twisted terminal nostrils, with much modified incisors, commonly 

 ^ ; premolars ^ or ^ in number, and molars with sharp tuber- 

 cles ; the second digit of the hind limb has a claw. This group 

 includes the Galagos, Pottos, Aye- Ayes, Loris, Indris, and the 

 true Lemurs; the three latter being restricted to Madagascar, 

 whence the group diverges in one direction to the continent of 

 Africa, in the other to the Indian Archipelago. The Platyrhines 

 are those with the nostrils subterminal and wide apart ; premolars 

 g^ in number, the molars with blunt tubercles ; the thumbs of 

 the fore-hands not opposable or wanting ; the tail in most prehen- 

 eile ; they are peculiar to South America. The Catarhines have 

 the nostrils oblique and approximated below, and opening above 

 and behind the muzzle: the premolars are ^ in number; the 

 thumb of the fore-hand is opposable. They are restricted to the 

 Old "World, and, save a single species on the rock of Gibraltar, to 

 Africa and Asia. The highest organized family of Catarhines is 

 tailless, and offers in the Orang and Chimpanzee the nearest 

 approach to the human type. 



under side of the ramus, a Httle in advance of the angle of the lower jaw in the 

 UrsidcB, remarks : — " The same character is also found in many Seals (Fhocidce), 

 which in several other respects appear to approach the bears." — Proc. Zool. Soc. 

 Sept. 1839. 



* With few exceptions in the anomalous Lemuridce. 



t Reduced to |£| in the Marmosets {Hapale, My das). 



X Among the Platyrhines, the placenta is single in MyceteSy double in Calli- 

 thrix : among the Catarhines, the placenta is double in MacacuSy CercopithecuSy 

 and Semnopithecus, single in Troglodytes. 



