278 



V. H. EDIiEWORTir. 



Ti-iton) or rudiineutary coudition (e.g. Rana. Pelobates, 

 Bufo) of the basiliyal. 



In the rabbit the Anlageti of the lingual muscles are formed 

 from the anterior part of the Anlage of the hypobranchial 

 spinal muscles, i.e. from the future genio-hyoid, in 9 mm. 

 embryos, that of the genio-glossus and lingualis by upward 

 growth, that of the hyo-glossus and stylo-glossus by an ont- 



Text-fig. 81. 



Juiv 



ai,'0Ui n\L( 



t-iife-'tkuoui 



Text-fiKS- Hl-83.— Ral.l)it, embryo -4 lum. Text fig. 81 is tlirough 

 the liyoid segment. Text-fig. 82 through the fourtli gill-cleft. 

 Text-fig. S3 through the third branchial gill-cleft. 



growth directed upwards and laterally (Text-tig. !>!). In lo 

 mm. embryos these muscles have separated from the genio- 

 hyoid, and become distinct (Text-figs. 94, 95). 



SoMK Phylogenetic Considerations. 



The probable phylogenetic relationships of the various 

 Vertebrate groups are determined by the total morphological 



