MORPHOLOGY OF CRAXIAL MFSCLES IN SOME VERTEBRATES. 217 



palato-quadrate to the ceratolijal ; the latter, which is the 

 hyomaxillaris, grows forwards to the outer end of Meckel's 

 cartilage and divides into the cerato-hyo-angularis, suspen- 

 sorio-angnlaris, and the quadrato-angularis (Text-fig. 59). In 

 Bufo lentiginosus the upper portion of the myotome forms 

 only an orbito-h3"oideus, as in Raua; in Pelobates and Alytes it 

 forms an orbito-hyoideus and suspensorio-hyoideus. In Pelo- 



Text-fig. 4.5. 



45. 



bates and Bufo lentiginosus the hyo-maxillaris divides 

 into three muscles as in Rana, in Alytes into two only, the 

 cerato-hyo-angularis and quadrato-angularis (Text-fig. 63). 



In Rana, at metamorphosis, the upper end of the orbito- 

 hyoideus extends upwards on the atrophy of the processus 

 muscularis of the palato-quadrate; subsequently, on rotation 

 backward of the palato-quadrate, the lower end of the orbito- 



' The coraco-mandilailaris in this drawing' is unfortunately not named. 



