FIG. 276. Nauplius Stage. Stage F. md, Mid-gut, the endodenn cells have assimilated 

 nutritive yolk; pr, proctodaeum (hind-gut); A, anus; TA, thoraco-abdominal rudiment; m, 

 mesoderm ; st, beginning of invagination of the stomodseum ; ec, ectoderm. 



FIG. 277. Stage G. en, The endodermal cells laden with yolk ; h, rudiment of heart ; pr, 

 proctodseum ; ks, germ zone ; A, anus ; m, mesoderm ; ?, upper lip ; st, stomodffium ; ec, ectoderm. 



m 



cja T 



Fio. 278. Stage H. Lettering the same. In addition : ss, sternal sinus; ga, ganglia of the 

 ventral chord ; T, telson ; g, supra-resophageal ganglion. 



