THE LATER DEVELOPMENT OF THE FROG 



173 



TABLE OF SOMITES, VERTEBRA, AND RELATED NERVES OF 

 THE TADPOLE (ELLIOT) 



Before the separation of the somites and lateral plate, the 



itter shows traces of segmentation in the region adjoining the 



unites, from which later the pronephros is formed (see below). 



is region may therefore be termed nephrotome or intermediate 



ill mass. These traces disappear very quickly, and the lateral 



)late itself is never segmented. The cavity of the lateral plate, 

 te general body cavity, gradually extends ventrally, and finally 

 ivides the entire lateral plate into somatic and splanchnic 

 lyers. Except in the extreme anterior and posterior ends of 



:he trunk, the cavities of the two sides meet and fuse across 

 ie mid-ventral line, establishing a continuous body cavity and 



