THE GLASS-CRABS OR PHYLLOSOMATA. 



307 



79, i?), had gradually in the pupa (Fig. 79, F^ G) assumed 

 the opposite curvature. Its dimensions are threefold those 

 of the embryo, and it exhibits vivacious movements when ex- 

 tracted from the pouch of the parent. It is not improbable 

 it may yet undergo another change of integument before ac- 

 quiring the full form of the adult. 



Thus it appears that, in Mysis^ the JVauplius-staige (Fig. 

 79, D, E) is passed over so rapidly that the embryo has gone 

 through it at a very early period, and nothing but the cuticu- 

 lar sheath of the body appertaining to this stage remains to 

 J rove its existence. A step further, in the abbreviation of 

 the J}^aiqjlius-stage, and there would be nothing to distin- 



■\ji 



Fig. SQ.—P/iT/Uosoma.—A, ventral view of the hody, with the limbs P-XX' of the 

 left side and the bases ouly of XF to XIIP represented. B. side view ot tiie 

 body. C, the nervous system. Z*, the last cephalic and tirst. and second thoracic 

 limbs. 



guish the general course of the development of Mt/sis from 

 that of Astacus. On the other hand, another Schizopod, 

 Euphausia^ has been shown by Metschnikoif ^ to leave the 

 Qgg as a true Nauplhis. 



1 Zeitschrift fur wiss. Zool., 1871. 



