METAMOEPHOSES OF THE CRUSTACEA. 



281 



In the Opossum-shrimps (Mysis) the 3'oung does 

 not leave the pouch of the mother until it is fully 



A 



Fig. 73. Pcnaus semisidcatus. A, adult (after de Haan. J nat. size) ; 

 B, Zoisa, and C, less advanced Zoa3a of a species of PencBus. D, 

 Nauplius. (B, C, and D, after Fritz Miiller.) 



