THE MUSCULATURE OF THE TRUNK. 297 



one next in front of it. The remaining ribs also have 

 intercostal muscles between them, but their fibres become 

 less and less better developed as we proceed back- 

 wards, and in all cases the strongest part of the muscle 

 is just above the articulations with the hremapophyses ; 

 and from these parts the muscles also gradually grow 

 more feeble as we approach the vertebral column, 

 where they are supplemented by the levatores costarum. 

 Both an internal and external set can be made out. 



Professor Owen, in his Anatomy of Vertebrates, does 

 not especially describe these muscles as occurring in the 

 Aptcryx. 



141. The scalenus medius T is the most anterior leader 

 of that series of muscles which follow it, called the 

 levatores costarum, but is sufficiently conspicuous to 

 deserve a separate name and description. It arises from 

 the diapophysis and pleurapophysis of the eleventh 

 cervical vertebra, and its fibres passing downwards and 

 backwards are inserted upon the entire length of the short 

 free rib which articulates with the twelfth vertebra ; and 

 the middle fibres passing over and beyond it are inserted 

 into the anterior free margin of the middle third or more 

 of the second or lono-er free rib next behind it. 



o 



1 We have the subjoined synonymy of this muscle from Gadow 

 (loc. cit., p. 124) : 



" 18e. M. SCALENUS. 



Les muscles qui tiennent la place des scalenes (pt.). Vicq d'Azyr. 

 M. scalene.. Cuvier. (Als den Vogeln fehlend angefuhrt). 

 Scalenus (Rippenhalter). Wiedemann, p. 78. 



(pt.). Tiedemaiin, 223 ; Meckel, System, p. 301, No. 1 ; 



Magnus, p. 220; Selenka, p. 98 ; Watson, p. 71. 

 Scalenus medius. Owen. 

 Surcostaux (pt.). Gervais et Alix, p. 12. 



Mtiscuhis feres inter prima/m et secundam costam. Tieduuiaun, 237. 

 M. teres. Magnus, p. 221." 



