1880.] NATURAL SCIENCES OF PHILADELPHIA. 393 



conspicuous. In Artibeus the superficial fibres occupy the anterior 



half of the fossa. In Desmodus the fibres are confined to the 



pj^ 2 anterior portion of the fossa ; 



they are weak and unimportant. 

 ^ The supra-zygomatic slip over- 



lies the tendon of the main 

 ''^^ muscle above the zygoma. In 

 ) Lonchoglossa the muscle is 

 ^ poorh'^ developed throughout. 

 The superficial fibres are re- 

 ^, , , , , , ■ -c- duced to mere rudiments. The 



The temporal and masseter muscles in a Fox 



Bat {Epomophorus). supra-zygomatic slip is present. 



.Yjf, Supei-flciai fibres of same. The deep portion does not 



XXX, Supra-zygomatic slip of masseter ■i.po/-.|i the vertex, 

 muscle. 1 . -r> • 1 



xxxx, Masseter muscle. The muscles in Ptcropme bats 



resemble those in the American 

 leaf-nosed forms. The superficial fibres are confined to the anterior 

 third or half of the temporal fossa as seen in Pteropus medms, 

 Epomophorus and Cyonycteris amplexicaudata. The supra- 

 zygomatic slip is relatively smaller than in the Phjdlostomidae. 



In 3Iegaderma frons and Phyllorhina bidens the paints bear a 

 general resemblance to the above group. The supra-zygomatic 

 slip is absent in the latter species. 



In 3I0I0SSUS the superficial fibres are enormousl}' developed, they 

 entirely cover the deep, and arise from a continuous osseous sur- 

 face at the vertex which, being broad anteriorly , narrows gradually 

 toward the occiput. The fibres arising from the vertex-crest, when 

 such is present, are those belonging to the superficial set. The 

 supra-zygomatic slip is present. A similar arrangement is seen 

 in Noctilio^ in which form the main mass of fibres possess an un- 

 usually deep set central tendon, and the superficial layer extends 

 backward along the line of the vertex to the occiput. Lasionyc- 

 teris, Atalapha, Vesperus and Vesperugo have an arrangement of 

 the temporal fibres similar to the above but vary in the degree of 

 development of the anterior slip. 



To sum up the knowledge possessed of the temporal muscle in 

 the Chiroptera it may be said that the deep portion is most ex- 

 posed in Pteropus and its congeners, and the family Phjdlos- 

 tomididae, owing to the small development of the anterior fibres. 

 In Yespertilionidse and Molossi the deep portion of the temporal 



