EXPLANATION OF PLATE VIIL 



Figure 36. — Squilla ernpusa Say, (p. 53G;) lateral view of the free-swimming larvae 

 in one of its later stages, enlarged, ten diameters. 



37. — Zoea of the common crab, Cancer irroratus, (p. 530 ;) in the last stage just- 

 before it changes to the megalops condition; lateral view, enlarged 

 seventeen diameters. 



38. — Megalops stage of the same, just after the change from the zoea condi- 

 tion ; dorsal view, enlarged thirteen diameters; 



(All tlie figures were drawn by J. H. Emerton.) 





