406 EDWIN G. CONKLIN 



EXPLANATION OF FIGURES 



7 Cross section through the body and tail of an entire typical larva showing 

 the nerve tube, gastric cavity, mesenchyme, chorda, caudal endoderm and 

 muscle cells, and general ectoderm. 



8 Cross section through the body and tail of a § larva. The neural plate is 

 not infolded and the endoderm cells are not entirely covered by ectoderm cells 

 on the injured side; the cross section of the tail is similar to that of fig. 6b. 



9 Entire preparation of a ^ larva, showing the superficial resemblance to a 

 typical larva. 



10 Cross section through the body and tail of a lateral | larva in a plane 

 similar to that of fiig. 7. The gastric cavity is nearly typical, neural plate cells 

 are not distinguishable in the body or tail, muscle cells are on one side only of 

 the chorda. This is one of the most typical 5 or f larvae ever seen. 



11 Section of anterior | larva, showing neural plate cells with eye pigment, 

 ectoderm and endoderm, but no mesoderm. 



12 Section of anterior and of posterior j larvae. Neural plate cells are shown 

 only in the anterior quarter, muscle cells only in the posterior quarter. 



