MOBPHOLOGY OF CRAXIAL :\IUSCLES L\ SOME VERTEBEATES. 281 



Esox (Vetter), Meuidia (Herrick), Amia (Allis), Lepidosteus' 

 the only coraco-branchiali's present, developed from the most 

 posterior branchial segment (fourth or fifth), is innervated by 

 the Xth ; whereas in others, e.g. Amieurus (Wright), Salmo 

 (Harrison), it is innervated by the spino-occipital nerves. 



(9) The coraco-branchiales of Acipenser, Ceratodus, and 

 Scyllium, developed in branchial segments, are innervated 

 by spino-occipital nerves (Vetter, Fiirbringer). The spino- 

 occipital nerves also innervate the four coraco-branchiales of 

 Polypterus (?) species, described by Fiirbringer. 



(10) The capito-dorso-clavicularis of Lacerta agilis, 

 developed from the primitive trapezius, i.e. from branchial 

 segments, is innervated by spinal nerves (Fiirbringer). 



(11) The cucullaris, i. e. trapezius, of Gallus, developed 

 from branchial segments, is innervated both by the Xlth 

 and by spinal nerves (Fiirbringer). 



(12) The trapezius and sterno-mastoid of the rabbit, 

 developed from branchial segments, is innervated both by 

 the Xlth and by spinal nerves. 



(13) The retractor arcuum branch ialium dorsalis of Amia 

 and Lepidosteus, developed from trunk myotomes, is inner- 

 vated by the Xth (AUis, Wiedersheim). 



(14) The hinder part of the hypobranchial spinal muscles 

 of the rabbit, which are developed from the first three spinal 

 myotomes, are innervated by more posterior spinal nerves. 



(15) The interarcnalis ventralis I, i.e. branchio-ln'oideus 

 or branchio-mandibularis of Sauropsida, is innervated by the 

 Xllth. 



Fiirbringer held that " Die Inuervirung der Muskeln 

 durcli bestimmte Xerven ist das wichstigte Moment fur die 

 Vergleichung." In criticism of tliis theory, Cunningham 

 gave instances from the myology of the trunk and limbs in 

 which this criterion failed, and concluded that the nerve 

 supply is " not an infallible guide " for determination of the 

 homology of a muscle. The above-cited observations show 

 that developmental phenomena should be taken into con- 

 sideration. 



