DEVELOPMENT OF E. LONGIROSTRIS 289 



The antennular spine is longer than the sum of the second and third peduncular 

 segments ; the flagella are represented by single segments. 



Of the second to eighth thoracic limbs the second only may be free as large simple 

 buds ; or the second and third may be free, the second large and beginning to bud off 

 exopod and gill, the third small and simple. 



A pair of narrow lateral protuberances stand strongly out from the tergum of the first 

 abdominal somite, their ends curved downwards and forwards : they are the beginnings 

 of the "tergal wings". The hinder lower edges of the pleura of the abdominal somites 

 are denticulate. There is a median posterior spine on the third abdominal somite, a 

 quarter to half as long as the fourth somite. The telson is very similar to that of the third 

 Calyptopis. 



Fur cilia, stage II 



Description based on the examination of six specimens, 5-0-5-4 mm. long. 



In this stage there is one pair of setose and three pairs of non-setose pleopods. 



The dorsal organ is a high and abrupt cone. The frontal plate is narrower than that of 

 Furcilia stage I, but in five of the specimens it is otherwise similar to it ; in the sixth 

 specimen there is a small spine, the beginning of the rostrum, shorter than the den- 

 ticles on either side of it, in the centre of the anterior margin. The lateral margins of the 

 carapace may, as in the previous stage, be denticulate from the antero-lateral spines to 

 the lateral denticles, the more anterior denticulations being very small or absent. The 

 posterior projection of the carapace is strong and of great length ; it may be as long as, 

 or longer than, the first three abdominal somites. 



The antennular spine is longer than the sum of the second and third segments of the 

 peduncle; the flagella are still unsegmented. 



The degree of development of the thoracic limbs is as follows : 



Second limb. Endopod of five segments and feebly kneed. A gill bud of two 

 branches. 



Third limb. Short, bifurcate and setose but not segmented, a single gill bud; or 

 endopod of three or four segments and gill bud budding off a second branch. 



Fourth limb. Free bud. 



Posterior limbs. Not free. 



The tergal wings of the first abdominal somite are stronger than in the previous stage 

 and bent farther forward distally. The hinder lower edges of the pleura of the ab- 

 dominal somites are denticulate. The spine of the third somite is stout and about half 

 the length of the fourth. The telson is similar to those of the two previous stages. 



Furcilia, stage III (Fig. 39/) 

 Description based on the examination of two specimens, 6-o and 6-3 mm. long. 

 In this stage there are four pairs of setose and one pair of non-setose pleopods. 



D XIV 13 



