AND AFFINITIES OF THE GORILLA. 275 



including the Ouistitis; and 3. the Old-World Simics. In these BufFon' had gene- 

 ralized the fact of the narrow septum of the nose, as he had also that of the broad nasal 

 septum in the New- World Monkeys. Etienne GeofFroy St.-Hilaire ^ invented names for 

 the two great groups expressive of these characters, e. g. Catarrhini and Platyrrhini. 

 Observing also a peculiar twist of the nostril in certain Lemurids, he proposed for that 

 group the term Strepsirrhini, to give uniformity of nomenclature to these three divi- 

 sions of the Quadrumana. The Lemurine group, including Chiromys and Galeopithecus, 

 offers, however, exceptions to the form and position of nostrils to a degree not known 

 in the two higher groups. The dentition and other important parts of the organiza- 

 tion present also more and greater modifications than in the Platyrrhines and Catar- 

 rhines. The difference in the relative size of the cerebrum between any known 

 Lemurine and the lower Platyrrhine is such as to indicate a higher degree of value to 

 the Strepsirrhine group, and that it is more distinct from the Platyrrhine^ than this is 

 from the Catarrhine group. Moreover, the Lemurines in their diversities of organiza- 

 tion are a less natural or circumscribed group, and their wider geographical distribution 

 accords with this conclusion. Of all the Gyrencephala, they have the closest affinities 

 with the Lissencephala ; yet the small smooth-brained Lemurines show a larger propor- 

 tional cerebrum than the Rodents or Insectivores of corresponding size''. 



With these admissions, retaining the Lemurines or Strepsirrhines as a primary group 

 and the lowest suborder of Quadrumana, I regard the Platyrrhines, or New-World Simiae, 

 and the Catarrhines, or Old-World Simice, as two other suborders, respectively more 

 circumscribed and natural than the lower one, and more nearly allied to each other 

 than to it. 



Of the subdivisions of these suborders it is not in my present aim to say more than 

 that I adopt as the highest group or " tribe " of Catarrhines, the Pithecina of Isidore 

 Geoffroy St.-Hilaire\ To the characters of teeth (common to it with all Catarrhines) 



' Histoire Naturelle, torn. xiv. p. 13. ' Annales du Museum, torn. six. pp. 85 & 156. 



' Mr. Blyth, in Orr's edition of the ' Regne Animal,' 8vo, 1840, remarks upon the Ouistitis, " Their brain is 

 surprisingly low, almost without convolutions." But, in my Memoir of 1837, it was shown that the Midas 

 rufimanus was superior to the smooth-brained Rodents and Marsupials in the greater relative size of the cere- 

 brum, which is a more important character. 



* See " Memoir on the Aye-aye (Chiromys)," Trans. Zool. Soc. vol. v. pp. 68 & 84,"pl. 24. figs. 2-5. 

 ' Archives du Museum d'Hist. Nat., 1839, " Sur la classification et les caracteres des Mammiferes, Premiere 

 Memoire, Famille des Singes." 



" Tribu I. PiTHECTENS, Pithecina : Singes II cinq molaires (32 dents en tout), a ongles courts, a membres 

 antSrieurs plus longs que les posterieurs." 



Van der Hoeven, excluding Gahopilhecus from the order, divides the Quadrumana primarily into Lemurina 

 seu Prosimii and Simi^. The latter group he subdivides into — 



" Phalanx I. Hemipitheci. 



II. Hesperopitheci. 

 III. Heopitheci." 

 The first two answer to the Platyrrhines; the third to the Catarrhines. In this arrangement the genera 

 VOL. v. PART IV. 2 O 



