.MORPHOLOGY OF CRANIAL MUSCLES IN SO:\[E VERTEBRATES. 167 



On the Morphology of the Cranial Muscles in 

 Some Vertebrates. 



By 



F. H. Edarewoitli, :tl.l>., D.Sr., 



Professor of Medicine. University of BristoL 



With 10(1 Text-fio-urcs. 



Ix the following paper I have described and compared 

 the development of some of the cranial muscles in Scyl- 

 lium canicula, Squalus acanthias, Acipenser sturio, 

 Lepidosteus osseus, Araia calva, Sal mo fario, Cera- 

 todus Forsteri, Triton cristatus, Rana temporaria, 

 Alytes obstetricans, Bnfo lentiginosus, Pelobates 

 fuse us, Chrysemys marginata, Lacertaagilis, cluck, 

 rabbit, and pig. 



The object has been to determine as far as possible the 

 morphology of the muscles, and so to deduce a morphological 

 classification of the motor nuclei of the cranial nerves, more 

 especially in mammals and man. 



A subsidiary object has been to ascertain what evidence is 

 afforded by these muscles in regard to the speculations of 

 zoologists on the phylogenetic relations of the various verte- 

 brate groups. 



The paper is a sequel to one previously published on some of 

 the cranial muscles of Sauropsida. 



The adult anatomy of the muscles has been^lescribed by 

 Yetter, Furbringer, Pollard, McMurrich, Allis, Jaquet, 

 Druner,Ecker and Gaupp, Mivart, Krause, and others referred 

 to in the paper. In the majority of cases observation of the 

 development of the muscles merely serves to support deduc- 

 tions as to their homologies ah-eady made from consideration 



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