X.] 



THE CKANIAL FLEXURE. 



333 



dfp, splanchnic mesoblast; ph. pericardial section of body- 

 cavity ; aUi. muscular waU of heart ; ihh. epithelioid layer of 

 heart ; me*, lateral undivided mesoblast ; sw. fold of hypo- 

 blast which will form the ventral wall of the pharynx ; sr. 

 commencing throat. 



The later stages in the development proceed in the 

 main in the same manner as in the Bird. The cranial 

 flexiire soon becomes very marked, the mid-brain form- 

 ing the end of the long axis of the embryo (Fig. 108). 

 The sense organs have the usual development. Under 

 the fore-brain appears an epiblastic involution giving 



Fig. 108. 



mS 



am 



Advanced Embryo of a Kabbit (about Twelve Dats)^ 



mh. mid-brain ; th. thalamencephalon ; ce. cerebral hemisphere ; 

 op. eye ; iv.v. fourth ventricle ; mx. maxillary process ; md. 

 mandibular arch ; hy. hyoid arch ; fl. fore-limb ; hi. hind- 

 limb ; um. umbilical stalk. 



1 This figure was drawn by Mr Weldon. 



