l.ls TAdio sis(i(;sMKmi 



riii/iininlrs (Ph.) (//olxisd. 



All the specimens of this species dealt with below, mature females and males as well 

 as larvae, were collected during the Swedish Greenland K x p e d i t i o n, I8i»i», 

 all on the same occasion, the ITthofJuly. and at tiie samr place, lat. 74" 10' N., long 20"8' \V., 

 depth 25 — 40 m. It seems to me certain that tliev all really belong to this species, partly for 

 morphological reasons and partly because at the locality in (|uesti()ii probably only this species 

 of this genus is found, (f. this species in the special part below. 



Six free-living larval stages could be distinguished. 



General description of the larval stages: — 



Stage I: — 



Male: As has alreadv been pointed out by preceding authors (cf. the special part of 

 this work), this differs strikingly from the mature male. Shell: Average length, 2,4 mm. 

 It agrees entirely with the shell of the mature female. The first a n t e n n a, the m a n- 

 d i b 1 e, the maxilla and the fifth, sixth and seventh limbs are also of the 

 same t^•pe as those of the mature female; the posterior limbs have perhaps a somewhat smaller 

 number of bristles. Second antenna: The protopodite and exopodite have the same 

 appearance as in the mature female, but the bristles on the four distal joints of the exopodite 

 are primarily short and without natatory hairs; for the endopodite see the figure of this 

 organ of this species in the special part below. The f u r c a has eight claws, which decrease 

 fairly uniformly in length and strength the more proximally they are situated. The lateral 

 eves are almost of the same size a,s in the mature male, but are only very slightly pigmented. 



Female: This agrees completely with the male of this genus except in the 

 sexual character s, the endopodite of the second antenna and the lateral 

 eves; in the latter characters it resembles the mature female, but is more larval in type. 



Stage II: — 



^I a 1 e: Shell: Average length, 1,9 mm. The endopodite of the second antenna 

 is considerably smaller and much less differentiated than in Stage I; its second joint has 

 only two bristles. The posterior limbs have somewhat fewer bristles and the lateral 

 eyes are considerably smaller than in the preceding stage. The f u r c a has eight claws. 

 Otherwise this stage agrees with Stage 1. 



Female: This agrees completely with the male of this stage except in the sexual 

 characters, the endopodite of the second antenna and the lateral eyes; in the latter characters 

 it resembles the female of Stage I, but is more larval in type. 



In the following larval stages I did not succeed in distinguishing with certainty between 

 males and females by means of dissection. 



Stage III: — Shell: Average length, 1,5 mm. In this stage too all the limbs are 

 present. The seventh limb, however, is only represented by a long, unjointed, upward point- 

 ing appendage, which is quite without bristles. Sixth limb: The end joint is furnished 

 ventrally with only about eight bristles. Other limbs are also furnished with fewer bristles than 

 in the preceding stages, but. like the sixth limb, they have about the definitive type. Each 



