TANm 



Fig. 276.— Naupllus Stage. Stage F. md, Mid-gut, the endoderm cells have assimilated 

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

 mesoderm ; s(, beginning of invagination of the stomodEeum ; ec, ectoderm. 



Fig. 277.— Stage G. en, The endodermal cells laden with yolk ; h, rudiment of heart ; jir, 

 proctodeeum ; Icz, genn zone ; A, anus ; m, mesoderm ; I, upper lip ; st, stomodEeum ; ec, ectoderm. 



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

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



