422 
Proceedings of Royal Society of Edinhurgh. [jult 2, 
In a stage immediately succeeding that already described, the 
only advance appears to consist in the elongation of the first pair of 
pereiopods, which are simple from the commencement, and, so far 
as I could ascertain, never pass through a Schizopod stage. In a 
later stage there are two pairs of simple pereiopods, in another three ; 
and finally the largest specimens have five, of which the fourth and 
fifth are not yet fully developed. 
The uropods make their appearance after the first pair of pereio- 
pods are fully developed, and at the same time a pair of simple 
hooked processes are developed just in front of them, as on the 
other abdominal segments (fig. 2). A comparison of this type of 
Fig. 1. Fig. 2. 
Fig. 1. — Tradielifer larva before the formation of the uropods. 
Fig. 2. — Yentral view of the uropods and telson in the oldest larva obtained. 
larva with those of Lucifer shows that, although the outward form 
is much the same, there are several important points of diver- 
gence. 
Larvae of Lucifer^ before reaching the stage corresponding with 
my fig. 1, have the pereiopods, pleopods, and uropods well developed, 
and the eyes are on longer stalks. The triangular form of telson is 
not represented in any of the Lucifer larvae. 
