7 8 DISCOVERY REPORTS 



a regular row of strong teeth which become smaller proximally ; near the base the margins become 

 strongly concave forming an angle on each side and giving rise to a marked dilatation similar to that 

 found in B. microps and B. rostrata (Fig. 12 F, G). Length. None of the Discovery specimens is 

 fully mature. The largest female, measuring 14-8 mm. has small incubatory lamellae. A female 

 (recorded as B. microps) by Tattersall (1939, p. 231) measured 17 mm. The male of the species has 

 not been seen. 



Remarks. B. tattersalli closely resembles B. microps but may be distinguished from it by the 

 following characters: (1) the longer, more acutely pointed rostrum; (2) the larger eyes, with the cornea 

 wider than the eyestalk and situated terminally, occupying the whole of the distal end of the organ 

 (in B. microps the cornea is small and confined to the outer region of the distal end of the eyestalk so that 

 the visual elements look essentially outward and, in dorsal view, the cornea appears as a narrow 

 band); (3) the absence of a spine at the proximal end of the emargination on the carpo-propodus of 

 the second thoracic endopod. 



Nouvel (1943, p. 57, pi- ni, figs. 77-84) described a new species, B. incisa, in which also there is 

 no spine at the proximal end of the emargination of the second thoracic endopod, but this species 

 can be distinguished from B. tattersalli by the longer, sharper rostrum, the much larger, globular 

 eyes and, especially, by the form of the telson which does not have a dilatation at the base of the cleft 

 and in which the spines arming the lateral margins are almost equal in length. 



Distribution. The Discovery specimens were taken in equatorial waters of the West Arabian Sea 

 in closing nets fishing between 1400 m. and 700 m. The John Murray specimens were taken in the 

 Central Arabian Sea in two vertical hauls to the surface and in one closing net fishing between 400 m. 

 and 645 m. 



Tattersall (1939), in his report of the mysidsof the John Murray Expedition, referred four female 

 specimens from the Middle Arabian Sea to Boreomysis microps. When making the figures for this report, 

 I failed to find in these specimens the strong spine marking the proximal end of the emargination of 

 the inner margin of the carpo-propodus of the second thoracic endopod, which is a characteristic 

 feature of B. microps. Tattersall did not comment on this point in his text. In the Discovery material 

 there are some immature females taken in the West Arabian Sea, which agree precisely with the 

 specimens from the John Murray collection. Through the courtesy of Dr Isobel Gordon of the 

 British Museum of Natural History, I have been able to re-examine the John Murray specimens and 

 have found that they agree completely with the Discovery specimens. I have therefore referred them 

 all to a new species and, since my late husband was the first to see it, I have great pleasure in naming 

 it Boreomysis tattersalli in honour of him. 



Boreomysis bispinosa sp.n. 



Occurrence: ^ °' ' 



St. 85. 23. vi. 26 (night). West of Cape Town, 200o(-o) m., 1 badly damaged ? specimen, too broken to measure. 



St. 86. 24. vi. 26 (day). West of Cape Town, iooo(-o) m., anterior end of large $. 



St. 89. 28. vi. 26 (day). Off Cape Town, iooo(-o) m.,i juv. cJ. 



St. 239. 2. vi. 27 (day). North-east of South Georgia, i35o-io5o(-o) m., 1 adult $, 26 mm. 



St. 2033. 6. iv. 37 (day). West of Cape Town, 1350-1250 m., 1 adult $, 23 mm. (Colour note, 'Deep brilliant 



orange red'.) $ Type. 

 St. 2057. 29. iv. 37 (day). North east of St Helena, 1450-700 m., 1 adult <$, 22 mm. (Colour note, 'Brilliant orange 



generally; thoracic limbs and antennae tinged with rose red'.) $ Type. 



Description. Carapace very short anteriorly, anterior margin rounded with extremely short, 

 upturned rostral projection not reaching the bases of the eyestalks ; antero-lateral angles produced 



