84 DISCOVERY REPORTS 



In Hansen's figure of the anterior end of B. fragilis (1912, pi. 1, fig. 3 a), the apex of the antennal 

 scale is equal in length to the spine terminating the outer margin, but in the specimens which I exa- 

 mined from Albatross stations 4676 and 4655 the apex extends well beyond the terminal spine. 

 Hansen mentions that the lateral margins of the cleft of the telson are divergent, but in his figure 

 (pi. II, fig. 1 a) the cleft is very much narrower than in the specimens which I saw. 



B. acuminata may be distinguished by the very acutely pointed rostrum, which is longer in the 

 female than in the male, by the broad antennal scale with its very short apex and longer terminal 

 spine of the outer margin, by the peculiar form of the eyes with the small cornea looking essentially 

 outward, by the relatively broad telson with its very deep, narrow cleft and by the short, robust, 

 almost regular spines arming the lateral margins of the telson. 



Distribution. At all the stations where this species was taken by 'Discovery II', it was cap- 

 tured in deep water between 1400 m. and 2000 m. It is evidently a bathypelagic form. Three of the 

 stations were near the equator in the west of the Gulf of Guinea and the fourth was to the west of 



St Helena. 



Subfamily SlRIELLINAE 



Genus Siriella Dana, 1850 

 1829 Cynthia J. V. Thompson, p. 57. 

 1850 Siriella Dana, p. 129. 

 1850 Cynthilia White, p. 46. 

 1 86 1 Promysis Kroyer, p. 70. 

 1882a Protosiriella, p. 27; Siriellides, p. 32; Rhinomysis, p. 35; Heterosiriella, p. 38, Czerniavsky. 



1884 Pseudosiriella Claus, p. 275. 



Siriella thompsonii (Milne-Edwards) 1837 



1837 Cynthia thompsonii H. Milne-Edwards, p. 462. 



1852 Siriella vitrea Dana, p. 656, pi. 43. 



1852 Siriella brevipes Dana, p. 658, pi. 44. 



1861 Cynthia inermis Kroyer, p. 44, fig. 6a-g. 



1868 Siriella edwardsii Claus, p. 278, figs. 



1882a Siriellides indica Czerniavsky, p. 103, figs. 



1885 a Siriella thompsoni G. O. Sars, p. 205, pi. 36, figs. 1-24. 

 1910 Siriella thompsonii, Hansen, p. 31. 



1911a Siriella thompsonii, W. M. Tattersall, p. 193. 



1912 Siriella thompsonii, Hansen, p. 192. 



1943 Siriella thompsoni, Nouvel, p. 62. 



195 1 Siriella thompsonii, W. M. Tattersall, pp. 7, 9, 10, 60. 



Occurrence : 



St. 34° 23' N., 14 32' W. 14. x. 25 (day). East of Madeira, surface, 4 adult ?V (1 ovig.), 1 juv. $, 4-5-5 mm. 

 St. 87. 25. vi. 26 (day). South Atlantic, West of Cape Town, iooo(-o) m., 1 ovig. 9, 5 mm., 1 juv. $, 1 juv. $. 

 St. 89. 28. vi. 26 (day). Off Cape Town, 2 hauls: (i) iooo(-o) m., 1 adult $, 10 mm., 1 small juv. $; (ii) iooo(-o) m., 



1 $, 9-5 mm., not fully adult. 

 St. 256. 23. vi. 27 (day). South Atlantic, west of Cape Town, 850-1 ioo(-o) m., 3 very small juv. 

 St. 257. 24. vi. 27 (night). West of Cape Town, 25o(-o) m., 3 adult £$, 11 mm., 1 adult <$, 8-5 mm., 3 ovig. ?$, 



largest 10 mm., 3 ?$ juv. 

 St. 258. 25. vi. 27 (night). West of Cape Town, 450-320 m., 1 imm. $, 7-5 mm. 



St. 268. 25. vii. 27 (night). Off Cape Frio, iooo-i5o(-o) m., 9 adult <$$, largest 10-5 mm., 2 adult ??, 7-5 mm. 

 St. 437. 20. ix. 30 (night). East of Durban, 123-0 m., 1 adult S, 1° mrn. 

 St. 441. 22. ix. 30 (night). South-east of Durban, 180-0 m., 1 adult <J, 9 mm. 

 St. 448. 10. x. 30 (night). South-west of Cape Town, 161-0 m., 1 adult <$, 11 mm. 

 St. 673. 25. iv. 31 (night). West of Tristan da Cunha, 340-0 m., 2 c?o*. larger 11 mm., 1 juv. $. 



