MAMMALS. 571 



a nasal process dividing the external nasal aperture into two lateral 

 openings ; the spina nasalis is a vestige of this. By their lowest 

 portions, which form the anterior margin of the palate, the two 

 intermaxillaries join each other; to this many of the Chiroptera 

 present an exception, where instead of the junction a mere space is 

 left. The anterior margin of the intermaxillary bones is very thin, 

 when the incisor teeth are wanting at this part, as in Lemur; on 

 the other hand, the intermaxillaries are massive and strong in the 

 rodents and the elephant. In many species of mammals these 

 bones coalesce in old individuals, especially at the anterior surface 

 with the superior maxillary bones; in the human foetus they are 

 present as distinct ossific points until the fourth month only, whilst 

 after birth there is but a trace remaining in the palate of their 

 original distinctness. To these bones belongs the anterior palatine 

 foramen (or foramen incisivum), which in the carnivorous, the rumi- 

 nating and the solidungulate animals is double. The superior 

 maxillary bones are more elongated than in man and have a broader 

 nasal process. In the ant-eaters, the scaled quadrupeds (Manis) and 

 the true cetaceans these bones approximate to the extraordinary length 

 which we formerly remarked in the crocodiles. The malar bones 

 run from the superior maxillary bones to the zygomatic process of 

 the temporal bone; in the sloth (Bradypus) these bones do not 

 meet the last-named, and are moreover distinguished by a long, flat 

 process descending on the outside of the lower jaw and terminating 

 below in a point. In the other mammals, on the contrary, the malar 

 bone is usually connected with both bones; in the hippopotamus, 

 the solidungulate, ruminant and quadrumanous animals it is also 

 connected to the frontal bone by an ascending process; but in the 

 monkeys and in man alone is it also united with the great ala of the 

 sphenoid and forms with it a wall by which the cavity of the orbit 

 is separated from the temporal fossa, so that a fissure only is left 

 (Jissura spheno-maxillaris s. orbitalis inferior] , which consequently 

 does not exist in other mammals 1 . The malar bones in Manis and 

 some other insectivorous mammals (Sorex, Centetes) appear to be 

 absent, and although in the Monotremes the zygomatic arch is per- 

 fect, yet OWEN is of opinion, that here it is formed exclusively by 



1 HALLER was thus justified in saying " Homini major quam ulli Bestiarum orbita 

 pars ossea est" (Elem. Phy&iol. v. p. 343), which BLUMENBACH has misconceived, as 

 though HALLER meant that the orbit in man is comparatively the largest. Jfandb. der 

 vergl. Anat. 1824, s. 32. 



