THE CARCINUS M^NAS. 



453 



Next come the mandibles, and then the maxillfe, and these are 

 followed from before backwards by swimming legs and the germs 

 of five pairs of true walking legs, and of the branchiae. The pleon 

 consists at this stage of six segments, five upon one plan, and the 

 last different. The first five are simple articulations, but the germ 

 of the future true swimming legs — pleopoda — are. noticed upon 



Carcinus manas. 

 A zoea after the rupture of the tunic. 



one or two of them. The last appendage of the pleon is the 

 future telson of the adult crab. 



Repeated moults of the skin, probably at intervals of seven or 

 eight days, succeed each other, producing at each stage but little 

 change to the eye but that of size. At the expiration of a month 

 there is not very much alteration in the Zoca except that of bulk. 



The examination of individual parts will, however, exhibit 

 some progress in the development of each member in relation to 



