128 PERCY SLADEN TRUST EXPEDITION 



armed with a pair of plumose setae at the apex and seven to ten small spines on each 

 lateral margin. The tip of each lobe of the cleft bears three short stout spines and the 

 lateral margins of the telson are armed along their distal half with seven small spines. 

 The dorsal surface of the telson is somewhat deeply channelled in the median line. 



The inner uropod is about once and two-thirds as long as the telson and is armed 

 along its inner margin with ten long, rather stout spines, somewhat distantly set and not 

 reaching to the apex. The outer uropods are a little longer than the inner. 



Length of an immature female, 5 mm. 



lUig makes no mention of the hispidity of the pleon or of the spines arming the inner 

 uropod, and the shape of the telson as he depicts it is somewhat different from that shown 

 in fig. 7, but I have little doubt that the two forms belong to the same species. 



Order EUPHAUSIACEA. 



Family Euphausiidse. 



Genus Thysanopoda, H. Milne-Edw. 



15. Thysanopoda tricuspidata, H. Milne-Edw. 



Stations. D, surface, two, 5 and 5"5 mm.; P, 20 fms., twelve, 7 — 11 mm.; Q, surface, 

 twenty ; a, 150 fms., one, 5 mm. ; e, 300 fms., one, 10 mm.; n, surface, ten ; q, 1000 — fms., 

 two, 10 and 12 mm.; s, 250 — fms., five, 5 — 15 mm.; dd, surface, thirteen; 11, 750 fms., 

 one, 17 mm. 



16. Thysanopoda CBqualis, Hansen. 



T. CBqualis, Hansen, 1905. 

 T. CBqualis, Tattersall, 1909. 

 T. CBqualis, Hansen, 1910. 



Stations. C, 1200 — fms., eight, 8 — 16 mm. ; L, 75 fms., one, 15 mm. ; N, 600 — fms., 

 two, 12 mm. ; 0, 180 — fms., one, 8 mm. ; Q, surface, one, 1 3 mm. ; c, 300 fms., one, 9 mm. ; 

 p, 600 fms., one; q, 1000 — fms., four, 12 — 17 mm.; r, 500 — 250 fms., one, 16 mm.; s, 

 250 — fins., two, 14 and 16 mm.; s, 750 — 500 fms., two, 12 and 16 mm.; aa, 900 — fms., 

 two, 12 and 13 mm.; 11, 750 fms., four, 13—16 mm. 



I have nothing to add to Hansen's description of this species, with which these 

 specimens are in perfect agreement. It is very closely allied to T. obtusifroiis, G. O. Sars, 

 from which it is distinguished by the shape of the antennular lobe and the structure of the 

 copulatory organs of the first pleopods in the male. I would point out that both species 

 have the telson armed dorsally with two rows of many spines, which, when broken off, 

 have the appearance of two serrated keels. Sars has described this character for 

 T. obtusifiV7is, and it serves as a ready means of distinguishing these two forms from 

 their allies. 



17. Thysanopoda monacantha, Ortmann (Plate 7, fig. 8). 



T. monacantha, Ortmann, 1893. 

 T. agassizii, Ortmann, 1894. 



