﻿58 PLEISTOCENE MAMMALIA. 



from the temporal ridge and posterior border of the supra-orbital process. The anterior 

 part of the third and internal branch springs from the lower portion of the temporal fossa, 

 while the posterior takes its origin from the parietal. Several muscles of the eye, namely, 

 those for the rotation and general movement of the eyeball and the eyelids, also have their 

 point d'appui in this part of the skull. The rectus internus or " grand adducteur" and 

 " petit adducteur" of Straus-Durckheim, equivalent to a portion of the choanoid, rise near 

 the orbito-sphenoidal suture. Above them are the roots of the rectus superior or " grand 

 elevateur" and the " petit elevateur" of the same author, equivalent to another portion of 

 the choanoid ; and above these is that of the elevator of the upper eyelid. The palpebral, 

 in addition to its other attachments to the maxillary, the lachrymal, and the fronto-malar 

 ligament, springs also from the extremity of the supra-orbital process. Of the muscles of 

 the ear, the " sourcilio-scutien" of Straus-Durckheim does not appear to be represented in 

 man. It rises within the orbit, and performs the function of bringing forward the ear. 

 Another muscle taking part in the same office, the fronto-auricularis, springs from the 

 superciliary ridge. The scutiform cartilage is attached by means of the temporal aponeu- 

 rosis to the anterior part of the temporal fossa. To it are attached muscles which control 

 the motions of the ear. In the temporal aponeurosis a considerable portion of the 

 great temporal muscles takes its origin, besides other muscles of no particular im- 

 portance. 



§ 18. Nasals (Pis. VII, X, No. 15). — The nasals in Eelis are two thin plates of bone 

 forming the anterior part of the roof of the skull. They are scalene-triangular in form, 

 deeply curved transversely, nearly straight longitudinally, and united somewhat loosely by 

 a long, straight, deep suture. They form the upper covering of the nostrils, being 

 articulated behind to the frontals by a deep overlap, as we have described in our description 

 of that bone, laterally to the maxillaries by a suture, the inner edge of which projects into 

 the nasal cavity, forming a sharp ridge for the attachment of the anterior branch of the 

 ethmoid. They are also articulated for a short distance to the inner and upper edges of 

 the nasal processes of the inter- maxillaries. In the living animal the anterior edges of the 

 bones afford attachment to the epirhine cartilage anteriorly, and to the pararhine externally, 

 which form the outer portions of the nostrils. 



The nasals appear generally to be stouter and more decidedly triangular and flatter 

 posteriorly in the lion than the tiger, being depressed so as to form a median groove at the 

 symphysis in the latter animal. 1 M. de BlainvihV also notes as differences in the latter 

 animal as compared with the lion — " La declivite des os du nez, qui sont aussi plus etroits, 

 plus allonges, plus parallelogramiques, le lobe inferieur de leur bord libre etant plus pro- 

 longe et plus detache :" we have found, however, that the variations are so great in these 



1 Owen, ' Proceed. Zool. Soc.,' 1834. 



2 ' Ost. Felis/ p. 28. 



