SYSTEMATIC REPORT 73 



In B. rostrata the lateral margins of the telson are armed with eight to ten very long strongly developed 

 spines, the spaces between them being occupied with a number of much smaller spines in graduated 

 series. In B. illigi the lateral spines are shorter and relatively stout and, although they do show some 

 arrangement in series, there is no very marked difference between the sizes of the large spines and the 

 small ones. The form of the cleft of the telson is the most striking difference between the two species. 

 In B. illigi it is deeper than in B. rostrata and its proximal end is rounded without lateral slits or 

 a dilated area. The unarmed portion of the outer margin of the exopod of the uropod is relatively 

 much longer than in B. rostrata and its distal end is marked by two spines instead of one. The endopod 



Fig. 11. Boreomysis plebeja Hansen. A, telson and right uropod of male in dorsal view, x 16. 



Boreomysis illigi sp.n. (B-E). B, anterior margin of carapace of female in dorsal view, x 12; C, anterior end of 

 female in lateral view, x 12; D, right antenna, x 16; E, telson and right uropod in dorsal view, x 16. 



is armed with two long spines distal to the statocyst; in B. rostrata there is only one spine. The form 

 of the eye is very characteristic in B. illigi. It is larger than in B. rostrata and the long, strong ocular 

 papilla, with a large ganglion clearly visible at its base, projects forward beyond the anterior margin 

 of the cornea. 



Distribution. Illig's male specimens were taken at two stations in the Atlantic, one to the south 

 of the Canary Isles and the other to the south of Sierra Leone, and at one station in the Indian Ocean 

 near Ras Hafun. The Discovery records extend its known geographical range considerably to the 

 southward in the eastern waters of the South Atlantic. 



It appears to have a considerable vertical range. Illig's specimens were all taken in vertical hauls, 

 but at Discovery station 696 it was taken in a closing net fishing between 1000 and 750 m. and at station 

 1602 in a closing net fishing between only 300 and 470 m. At station 2034 an adult female was captured 

 in a night haul from 162 m. to the surface. 



