146 DISCOVERY REPORTS 



outer lip thin, straight in profile and obliquely retractive to the axis. Parietal wall deeply excavated. 

 Pillar flexuous and strongly recurved, but the end is broken in the only near adult specimen, so the 

 length of the anterior canal is not known. It cannot be very long, however, judging by the strongly 

 reflexed pillar. 



Height 36 mm. (actual), 38 mm. (estimated); diameter 18 mm. 



Localities. St. 159. Off South Georgia, 53 52' 30" S, 36 08' W, 21 Jan. 1927, 160 m. (holotype). 

 St. 160. Between South Georgia and Shag Rocks, 53 43' 40" S, 40 57' W, 7 Feb. 1927, 177 m. (two juveniles). 



Dentition. Fig. K, 68, p. 193 (St. 159). Protoconch. Fig. N, 105, p. 196. 



Subfamily Prosiphiinae 

 Genus Prosipho Thiele, 191 2 

 Type (s.d. Thiele 1929): Prosipho gaussianus Thiele 

 Prosipho astrolabiensis (Strebel) 



Sip/10 (IMohnia) astrolabiensis Strebel, 1908, p. 31, pi. 3, figs, yja-d. 

 Prosipho astrolabiensis Thiele, 191 2, p. 262. 



Type locality. Astrolabe I., 63 9' S, 58 17' W, 95 m. 

 St. 45. 2-7 miles S 85° E of Jason Lt., South Georgia, 6 Apr. 1926, 238-270 m. 

 St. 140. Stromness Harbour to Larsen Point, South Georgia, 23 Dec. 1926, 122-136 m. 

 St. 144. Off mouth of Stromness Harbour, South Georgia, 5 Jan. 1927, 155-178 m. 

 St. 190. Bismarck Strait, Palmer Archipelago, 64 56' S, 65 35' W, 24 Mar. 1927, 93-130 m. 

 St. WS 27. Off South Georgia, 53 55' S, 38 01' W, 19 Dec. 1926, 107 m. 



Range. Palmer Archipelago to South Georgia, 95-279 m. Melvill & Standen's record (1912) of 

 crassicostatus from Burdwood Bank, 56 fathoms, requires confirmation. 



Melvill & Standen (1912, p. 355) made this species a synonym of their Chrysodomus (Sipho) crassi- 

 costatus, described in 1907 (p. 138) from Scotia Bay, South Orkneys, 9-10 fathoms, off weed and stones. 

 Thiele (19 12) recognized both as distinct species of Prosipho. 



I have not seen shallow-water examples comparable with crassicostatus, which from Melvill & 

 Standen's figures appears to have coarser spirals and one less on the penultimate and body-whorl than 

 in astrolabiensis. 



This species and the next, chordatus Strebel, are very similar in size, build and sculpture, so much so 

 that they are separable only with difficulty, yet the radulae differ considerably. 



Both have a long basal outer extension of the laterals, like a handle, a peculiar feature of Prosipho, 

 but astrolabiensis is bicuspid, whereas in chordatus the laterals fan out above and have six cusps. All 

 the Prosipho radulae figured by Thiele (191 2) have more than two cusps: similis, glacialis, pusillus, 

 nodosus, gaussianus and certus. The central in all the species is narrow and deep based, more or less 

 rectangular and with three cusps. 



Radula. Fig. K, 56, p. 193. 



Prosipho chordatus (Strebel) 



Sipho} chordatus Strebel, 1908, p. 30, pi. 2, fig. 2ga-c. 

 Type locality. Cumberland Bay, South Georgia, 252-310 m. 

 St. 123. Off Cumberland Bay, South Georgia. From 4-1 miles N 54 E of Larsen Point to 1-2 miles S 62 ° W of 



Merton Rock, 15 Dec. 1926, 230-250 m. 

 St. 140. Stromness Harbour to Larsen Point, South Georgia, 23 Dec. 1926, 122-136 m. 

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

 St. 156. Off South Georgia, 53 51' S, 36 21' 30" W, 20 Jan. 1927, 200-236 m. 



Range. South Georgia, 122-310 m. 



