EXPLANATION OF PLATE VIII 
Ficurt 36.—Squilla empusa Say, (p. 536;) lateral view of the free-swimming larve 
in one of its later stages, enlarged ten diameters. 
37.—Zoéa of the common crab, Cancer irroratus, (p. 530 ;) in the last stage just 
before it changes to the megalops condition; lateral view, =e 
seventeen diameters. 
38.—Megalops stage of the same, just after the change from the zoéa ‘totidte 
tion ; dorsal view, enlarged thirteen diameters. 
{All the figures were drawn by J. H. Emerton.) 
