Fig. 279.— Stage J. Section not quite median. Lettering as before. In addition : cts, cephalo- 

 thoracic shield ; 7113, mesoderm segment.^ ; tgi, 1st thoracic ganglion (of 1st maxillipede) ; mg, 

 mandibular ganglion. 



mjl 



Fig. 280.— Ripe embryo. Lettering as before, mu, Moutli ; bm, ventral chord ; msc, muscu- 

 lature; aa, arteria abdominalis ; as, arteria stemalis ; M, diverticula of the raid-gut (hepatopancreas)- 

 h, heart ; pc, pericardium ; md, extensions of the mid-gut ; mm, muscles of the masticatory stomach ; 

 pk, pyloric valve. 



