114 



MR. E. S. GOODRICH ON THE OCCIPITAL RKGIOX 



in black, though not yet open. In front is seen the mandibular 

 somite, below the rudiment of the trigeminal ganglion. Behind 

 it lies the hyoidean somite, just in front of the vesicle and below 

 the facial rudiment. Posterior to the vesicle is the glossophar- 

 yngeal rudiment, below which extends the first metaotic somite 

 passing downwards into the first branchial arch. The vagus 

 rudiment extends over the next two and part of the 4th somite ; 

 the first myotome is placed over the 2nd branchial arch. 



Text-fig. 48 is a plan of a young embryo 3 mm. long, seen from 

 the dorsal aspect, the ners^ous system being partly removed. The 



Text-fiff. 48. 



mt.3 



Partial veconstraction of the anterior region of an embryo 3 mm. long, seen from 

 above. The greater part of the central nervous system has been removed to 

 expose the alimentary canal, notochord, &c. The first and second metaotic 

 somites overlie the first and second gill-arches. 



position of the somite with relation to the other structures is 

 much the same as in text-fig. 47. Lastly, in text-fig, 49 is drawn 

 the youngest stage we need investigate. The dorsal portion of 

 the 2nd postauditory somite has become closely pressed on to the 

 3rd somite, with which it remains intimately associated. Indeed, 

 in the latter stages it is seen to be indistinguishably fused with 

 it, the two combining to form the anterior region of that dorsal 

 muscle which in combination with the 3rd myotome makes up 

 the temporal muscle of the adult. Neither. at this nor at ajiy 



