300 DISCOVERY REPORTS 



The thoracic Hmbs of two specimens, {a) 6-o mm., (b) 6-7 mm. long, were examined. 

 Their degree of development is as follows : 



First limb, a and b. Endopod of two segments, longer than exopod. No gill bud. 



Second and third limbs, a. Endopod long and kneed. A gill of two branches. 

 b. Endopod long and kneed. A gill of two equal and a third smaller branch. 



Fourth limb. a. Endopod considerably shorter than third, kneed. A gill of two 

 branches, b. Endopod long but not kneed. Gill as in second. 



Fifth limb. a. A short bifurcate bud, the endopod setose but not segmented. A gill 

 of two branches, b. Endopod short but of five segments. A gill of two branches. 



Sixth limb. a. A very low bud. b. Bifurcate, non-setose. Gill of three unequal 

 branches. 



Seventh limb. a. A gill of two branches, b. A gill of two larger and two smaller 

 branches. 



Eighth limb. a. A very low bud. b. A small single gill bud. 



The spine of the third abdominal somite is very strong, nearly as long as the fourth 

 somite. The posterior margin of the telson is narrower than in the previous stage, 

 but it still carries seven spines. The middlemost of the postero-lateral spines is still the 

 longest ; the innermost is greatly thickened with a group of spines on the inner margin 

 where it narrows distally. 



Fur cilia, stage V (Fig. 40^, //) 

 Description based on the examination of three specimens, 7'4-7'5 mm. long. 



In this stage the antennal endopod is segmented and there are five terminal spines on 

 the telson. 



The dorsal organ is conspicuous but not very high. The frontal plate is not reduced 

 compared with that of the previous stage : it is still wide and square with denticulate 

 margins. But the rostral spine is much bigger, reaching nearly as far forward as the end 

 of the first segment of the antennular peduncle. The posterior projection of the carapace 

 reaches a half or a third way down the second abdominal somite. 



The antennular spine may be as long as the sum of the second and third peduncular 

 segments. 



The mandibular palp is small and unsegmented. 



The thoracic limbs of a specimen 7-4 mm. long are as follows : 



First limb. Endopod of five segments, not kneed, shorter than to knee of second. 

 No gill bud. 



Second to fourth limbs. Endopods long and kneed. Gills of one large and two small 

 branches. 



Fifth limb. Endopod shorter but kneed. Gill as in second to fourth. 



Sixth limb. Bifurcate, endopod of two segments, setose. Gill of three branches. 



Seventh limb. Gill of three large and other smaller branches. 



Eighth limb. Gill of two small and other smaller branches. 



