268 DISCOVERY REPORTS 



without, but mostly with a tiny spine at the centre ; in the smaller the lateral margins 

 are still nearly parallel and the anterior margin may be straight, but in the larger the 

 plate narrows a little distally (Fig. 36 h). It does not approach the " rounded triangular " 

 shape as in E. valient ini. 



The antennular spine reaches as much as two-thirds or more of the way up the third 

 peduncular segment ; the flagella are unsegmented. 



The development of the thoracic appendages varies from (i) Buds of second and third 

 free, remainder low and in a common integument ; second nearly as long as first, un- 

 segmented but bifurcated, endopod with terminal and other setae, a very small gill bud 

 (Fig. 36/); third about half the length of second, less completely bifurcated and with 

 no gill bud ; to (ii) Buds of second, third and fourth free ; second as long as first with its 

 endopod of five segments, with a big gill bud ; third half as long as second and bifur- 

 cated but not segmented, endopod with a terminal seta, with a gill bud ; fourth begin- 

 ning to bifurcate and to bud off a gill (Fig. 36 »). The majority lie between these two 

 extremes having the buds of the second and third appendages free and that of the fourth 

 becoming free, the second unsegmented, strong gill buds on the second and third. 



The tergal wings of the first abdominal somite are well developed (Fig. 36 h), but 

 they are not connected dorsally by a "collar" as in the same stage of E. vallentini 

 (Fig. 37 e). 



Fiircilia, stage III (Fig. 36 i, k) 



Description of thoracic appendages based on examination of twelve specimens, of other characters, 

 of sixty specimens. One hundred and forty-nine were measured. One taken unusually late in the 

 year (May i) measured only 5-0 mm.; the remainder fell between 5-5 and 6-7 mm.'^ 



In this stage there are five pairs of setose pleopods and the antennal endopod is un- 

 segmented. 



The carapace may have a crest too low to be called a dorsal organ or a small dorsal 

 organ not so big nor so abrupt as that of the same stage of E. vallentini. The frontal 

 plate is usually strongly rounded, though it does not narrow much distally, with a small 

 spiniform process in the centre of its anterior margin ; it may be broadly rounded with 

 no spiniform process. 



The antennular spine reaches about halfway along the third peduncular segment. 

 The flagella are either unsegmented or beginning to segment and about equal in length 

 to the sum of the second and third peduncular segments. 



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



First limb. Endopod unsegmented as in the earlier larval stages. 



Second limb. Considerably longer than the first, endopod of five segments and 

 feebly kneed (Fig. 36 2). 



Third limb. Endopod with five segments indicated or of five segments, much shorter 

 than to knee of second or reaching to it. 



'^ Rustad records one so small as 4-44 mm. taken in February in inshore waters. 



