420 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [76] 



Tlie gnathopods and peraeopods are essentially as in S. rohustus, ex- 

 cept tliat tbe fourth and fifth peraopods are much narrower and very 

 nearly as in 8. arcticus. 



The pleou is broad anteriorly, but strongly com])ressed i)Osteriorly, 

 and the dorsum rounded. The sixth somite is shorter than the antennal 

 scale, more than half as high as long, and very strongly compressed. 

 The telson is about as long as the sixth somite, snlcated as in S. rohustus, 

 and rather obtusely triangular at the tip, which, however, is mucronate. 

 The inner lamella of the uropod is about four times as long as broad 

 and regularly lanceolate in outline, without any angular expansion near 

 the middle of the outer edge. The outer lamella is nearly a third longer 

 than the inner, about four and a half times as long as broad, and the 

 outer margin terminates in a tooth about two-ninths of the length, or 

 the width of the lamella, from the tip. 



The peculiar sexual appendages (petasma) of the first pair of x^leopods 

 are very nearly as described and figured for S. rohustus, although there 

 is a little difference in the form and proportions of the hook-bearing 

 X)rocesses and unarmed stylets of the main branch of each appendage : 

 the lateral unarmed stylet (marked c in the figure of >S^. rohustus) is 

 stouter than in that species and truncated at the tip, while the mesial 

 stylet (d) is nearly as long as the hook-bearing process {g) with which 

 it is connected at base. 



The females are considerably larger and stouter than the males, the 

 l^eduncles of the antennulse are ai^parently a little shorter, and the eyes 

 slightly smaller. 



Although a considerable number of specimens have been taken by 

 the Albatross, none of them are perfect and most of them are in very 

 bad condition. 



The branchiae are all much smaller than in S. rohustus, the posterior 

 pleurobranchia of the twelfth (antepeiuiltimate) somite is replaced by 

 a simple lamella like that upon the somite next in front, and the two 

 branchiae of the penultimate somite are very small, as in JS. arcticus. 



Three specimens (7106) from Station 2051 give the following measure- 

 ments, of which some, on account of the imperfections and soft condi- 

 tion of the specimens, are only approximate : 



Sex 



Length from tip of rostrum to tip of telson 



Length of carapax along dorsum 



Length of e.yo-atalk and eye 



Greatest diameter of eye 



Length of peduncle of antennula 



Length of its distal segment 



Length of antennal scale 



Breadth of antennal scale 



Length of sixth somite of pleon 



Hight of sixth somite of pleon 



Length of telson 



Length of inner lamella of uropod 



Breadth of inner lamella of uropod 



Lengtli of outer lame'Ja of uropod 



Breadth of outer lamella of uropod 



50 



18 

 2.9 

 1.0 

 9.8 

 2.6 

 8.2 

 2.8 

 8.0 

 4.2 

 8.1 

 8.0 

 2.0 



10.8 

 2.4 



57 



21 

 3.0 

 0.9 



10.0 

 2.6 

 8.8 

 3.3 

 9.0 

 4.8 

 8.0 



72 



26 

 3.0 

 1.1 



13.0 

 3.2 



10.8 

 5.8 

 10.0 



