520 



F. H. EDGEWORTH. 



and, probably consequent on this, a suprastapedial is not 

 developed. 



The first branchial bar of Tropidouotus ^ is not developed 

 as a dorsi-ventral bar which subsequently rotates into its 

 adult position with lower end forward, but as a longitudinal 

 one (text-fig-. 38, p. 543). Its position and elongation back- 

 wards, together with the carrying back of the origin of the hyo- 



ling man 

 VL M. 

 ant mylo. 



Text-fig. 13. — Transverse section through an embryo of Gallus 

 at the middle of the sixth day. (For explanation of lettering see 

 p. 555.) 



glossus muscle, are evidently correlated with the development 

 of the (secondary) protrusible tongue. 



On the Number of Vertebras coalescing with the 

 Skull. — Suschkin^ described, in Tinnunculus, four vertebras 

 coalescing Avith the skull, each of which possessed, as tem- 

 porary procartilaginous structures, a pair of '^ cranial ribs." 



> It cannot be the ventral portion of the hyoid bar as Rutliko (cited by 

 Gaupp) thought, for, on its first appearance as a procartilaginous structure, 

 it lies behind the second gill-pouch, i. e. in the first branchial segment. 



2 Cited by Gaupp. 



