SYSTEMATIC 147 



Although they are of similar size and colour chordatus can be always distinguished from astrolabiensis 

 by the number of spiral cords which range, as the whorls increase, from two to four in astrolabiensis 

 and four to six in chordatus. If Melvill & Standen's figures of crassicostatus are correct, their species 

 shows the spiral cords increasing from two to three. The cords in astrolabiensis are narrower and 

 more sharply raised than in chordatus. 



Radula. Fig. K, 55, p. 193. 



Prosipho hunteri Hedley 



Prosipho hunteri Hedley, 1916, p. 56, pi. 8, fig. 92. 



Type locality. Commonwealth Bay, Adelie Land, 25 and 45-50 fathoms. 



St. 140. Stromness Harbour to Larsen Point, South Georgia, 23 Dec. 1926, 122-136111. 

 St. 152. Off South Georgia, 53 51' 30" S, 36 18' 30" W, 17 Jan. 1927, 245 m. 



These ' Discovery ' records extend the range of this species to the opposite side of the Antarctic 

 Continent. Although I have not seen actual topotypes, the South Georgia examples compare exactly 

 with Hedley's description and excellent figure. 



Height 6-o mm. ; diameter 3-0 mm. (holotype). 



Height 6-o mm. ; diameter 3-0 mm. (St. 152). 



Height 6-5 mm.; diameter 3-1 mm. (St. 140). 



Prosipho cancellatus Smith 



Prosipho cancellatus Smith, 19 1 5, p. 71, pi. 1, fig. 13. 



Type locality. Ross Sea, 76 56' S, 164 12' E, 160 fathoms. 



St. 1660. Ross Sea, 74 46-4' S, 178 23-4' E, 27 Jan 1936, 351 m. 

 The shell figured by Smith (loc. cit. pi. 2, fig. 15) from ' off Rio de Janeiro in 40 fathoms' appears to 

 be correctly identified, but the locality is certainly incorrect, as Smith suspected. 



Prosipho contrarius Thiele 



Prosipho contrarius Thiele, 1912, p. 209, pi. 13, fig. 1. 



Type locality. Gauss Station. 

 St. 1660. Ross Sea, 74 46-4' S, 178 23-4' E, 27 Jan. 1936, 351 m. 



Prosipho perversus n.sp., PI. VI, fig. 11 



This species is very similar to contrarius, but it is smaller and has more prominent spiral keels, which 

 increase to four instead of three over the last two whorls. Whorls 4^, including a narrowly conic 

 smooth protoconch of 1 whorl, which has an asymmetric nucleus. First and second post-nuclear 

 whorls with three well-developed spiral keels, penultimate with a fourth emergent from the lower suture 

 and body-whorl with four strong, equally developed keels. There are four spiral cords on the neck 

 and these are almost as strong as the keels. In contrarius there are seven comparatively weak cords on 

 the neck. 



Height 4-0 mm. ; diameter 2-0 mm. (perversus). 



Height 4-6 mm. ; diameter 2-3 mm. (holotype of contrarius). 



Height 5-6 mm.; diameter 27 mm. (contrarius, St. 1660). 



Type locality. St. 144. Off mouth of Stromness Harbour, South Georgia. From 54 04' S, 

 36 27' W to 53 58' S, 36 26' W, 5 Jan 1927, 155-178 m - ( one example, the holotype). 



