72 
PACIFIC SCIENCE, Vol. XXI, January 1967 
Figs. 42-46. Emerita rathbunae. Megalopa. 42, First maxilliped; 43, second maxilliped; 44, third maxil- 
liped; 43, pleopods (a, fourth, b, first); 46, uropods and telson. 
setae as found in the equivalent stage of E. 
rathbunae. In stage IV, the setation of the ex- 
opodites of the uropods becomes consistent and 
a useful character for differentiation of the 
species; larvae of E. analoga have 5 setae and 
those of E. rathbunae have 4 setae on this ap- 
pendage. In all subsequent instars, the setation 
of the coxal endite of the first maxilla may be 
used. The larvae of E. analoga develop a strong 
fifth seta subterminally on the proximal margin, 
while larvae of E. rathbunae apparently main- 
tain 4 setae throughout zoeal development. 
Differences in terms of size of carapace, ratio 
of length of carapace to rostral spine, and pro- 
portions of the telson increase between larvae 
of E. analoga and E. rathbunae as zoeal devel- 
