20 G- O. Sars. 



As to the animal, the rostral part of the head has be- 

 come considerably produced, terminating in a very acute 

 point, whereas its dorsal part is somewhat less convex than 

 in the preceding stage. 



The compound eye is more fully developed, and its 2 

 halves are about to join in the middle. 



The antennulæ are still rather short and claviform. 



The antennæ have quite lost the basal process, as 

 also the seta found in the preceding stage at the end 

 of the scape posteriorly, whereas the spine-like bristles in 

 front are more fully developed. The rami are now subequal 

 in length, the outer one resembling that in the preceding 

 stage, except that the 2 middle joints have each 2 spines, instead 

 of a single one, anteriorly. The inner ramus is divided 

 into 5 well-defined articulations and, like the outer, is provided 

 with scattered natatory setæ, both at the tip and on the 

 posterior edge. 



The number of branchial legs is apparently the same 

 as in the preceding stage, though perhaps a 9th pair is in 

 process of formation. The pedigerous part of the trunk is 

 more distinctly segmented, and the hairy dorsal protuberances 

 have considerably increased in number. 



The tail appears more deflexed, but otherwise exhibits 

 an appearance very similar to that found in the preceding 

 stage. 



The length of the shell in this stage measures 0,70 mm , 

 its height being 0,56 mm. 



Third postlarval stage. 



In this stage, which is not figured in the plates, 2 lines 

 of growth have appeared on the shell, which has thereby 



