THE CARCINUS MANAS. 453 
Next come the mandibles, and then the maxilla, and these are 
followed from before backwards by swimming legs and the germs 
of five pairs of true walking legs, and of the branchia. 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 nienas. 
A zoéa 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 Zoéa except that of bulk. 
The examination of individual parts will, however, exhibit 
some progress in the development of each member in relation to 
