PLATE Q 1 . 



Fig. 1. Diaptomus sp. Young male; external parts as yet but 

 partly developed showing alimentary and reproductive 

 systems as well as a portion of the muscular system. 

 The looped tube is the vas deferens. The small irreg- 

 ularly coiled tube anteriorly is the shell-gland or 

 kidney. 



Fig. 2. female with ovary , oviducts and heart. 



Figs. 3-4. Nauplius larva of same. 



Figs. 5-6. fifth pair of feet of male and female. 



Fig. 7. mouth appendages, anteriorly the base of antennae fol- 

 lowed by antennule, labrum, mandible with palp, max- 

 illa and maxilliped. 



