112 



MR. E. S. GOODRICH OX THR OCCIPITAL REGION 



clearly seen correspouding to the two pronephric funnels. 

 Myotomes 2 tind 3 give off diverticula passing beliind the 4th 

 branchial slit to form hypoglossal muscles. The ventral portion 

 of the first myotome is some way behind the auditory vesicle and 

 the rudiment of the hypoglossal ganglion. Below and in front 

 of the vesicle is the hyoidean somite ; while in front of the 

 rudimentary spiracular gill-slit lies the niandiljular somite. 



Text-fiff. 45. 



■ prn 



Partial vec on struct ion, seen from above, of the anterior region of an embryo in which 

 the mesoblastic skeleton has not yet appeared. The epidermal thickenings 

 cot responding to the glossopharyngeal and vagus nerves are indicated by 

 dots. 



Another embryo of about the same length, but a little younger, 

 is shown from the side in text-fig. 47. Here the auditory vesicle 

 is still quite continuous Avith the epidei'mis, and the relation of the 

 .somites to the gill-slits is well shown. The slits are represented 



