1888.] Messrs Brook and Hoyle on British Buphausiidce. 419 
expansion of the carapace, which is not absorbed. On 
account of this absorption the eyes, which become stalked 
and mobile, project beyond the sides of the carapace. This 
intermediate stage is represented by one, or perhaps two 
moults. 
6. Furcilia . — Compound eyes becoming more fully developed, and 
projecting much beyond the sides of the carapace. Antennae 
still retain their primitive natatory structure throughout this 
stage. Anterior pairs of legs and pleopods successively 
developed. 
This stage commencing when the eyes become exposed, 
and lasting so long as the antennae are biramous natatory 
appendages, includes a considerable number of moults. 
In one species there appear to be eleven moults, judging from the 
comparative development of the pleopods which become fully 
developed before the next larval stage is reached j thus — 
Stage 
1. No rudiments of pleopods. 
2. First pair of pleopods as simple rudiments. 
3. Second „ „ 
4. Third „ „ 
5. Fourth „ „ 
6. Fifth „ „ 
7. First pair of pleopods biramous and setose. 
8. Second „ „ 
9. Third „ „ 
10. Fourth ,, „ 
11. Fifth 
In another form the anterior pairs of pleopods become biramous 
and setose before the last pair are developed in rudiment. 
Cgrtojgia . — Antennular flagellum becoming elongate and distinctly 
articulate, so that these appendages cease to serve the purposes of 
locomotion. Posterior legs and gills successively appearing. 
In the post-larval stages succeeding the Cyrtopia all the legs are 
developed, the telson assumes its definite armature, and the various 
specific characters make their appearance. 
The earliest Cyrtopia larva obtained — one in which the antennal 
