SYSTEMATIC 179 



The radula of Bullinella alba consists of a small bilobed central tooth with a serrated apical cutting 

 edge, a massive hooked lateral with a median ridge of small denticles and five small hooked smooth 

 marginals. In Kaitoa scaphandroides there are only two marginals and none of the teeth bear serrations 

 or denticles. The central varies greatly in form and shows evidence of considerable wear ; it is normally 

 composed of two slightly overlapping convex ridged plates on a rectangular base. The lateral is massive 

 and robustly hooked and the two marginals are much smaller with long flexed hooks. The laterals in 

 Scaphandra are long, slender and incurved like mammalian ribs. 



Kaitoa scaphandroides n.sp., PI. X, figs. 69, 70 



Shell relatively large, cylindrical, with involute spire, the concave apex callused by an effuse extension 

 of the outer lip. Surface smooth except for axial growth lines and subobsolete, sparse spiral lirations. 

 Shell white, covered with a thick, dark, reddish brown epidermis. Outer lip thin, straight and slightly 

 protractive medially, truncated and broadly open below. Aperture narrow above but considerably 

 expanded below. Inner lip with a relatively broad callus which becomes thick over the concave columella. 

 There are no plaits, but the columellar callus is bordered by a groove followed by a narrowly arched 

 ridge. 



Height 19-2 mm. ; diameter 8-o mm. (holotype, St. 30). 



Height 23-0 mm. ; diameter 9-2 mm. (St. 30). 



Type locality. St. 30. West Cumberland Bay, South Georgia, 2-8 miles S 24 W. of Jason L., 

 16 Mar. 1926, 251 m. 



St. WS 62. Wilson Harbour, South Georgia, 19 Jan. 1927, 26-83 m. 



Dentition. Fig. M, 93, p. 195. 



There is a conical ferruginous deposit on the spire of the paratype. 



Genus Cylichnina Monterosato, 1884 

 Type (s.d. Cossmann, 1895): Cylichna strigella Loven. ( = Bulla umbilicata Montagu) 



„ ,. . . . 011 Mediterranean 



Cylichnina georgiana btrebel 



Cylichnina georgiana Strebel, 1908, p. 10, pi. 2, fig. 2oa-c. 



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



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. 



Cylichnina cf. gelida (Smith) 



Bullinella gelida Smith, 1907, p. 12, pi. 2, fig. 12. 



Cylichna gelida Thiele, 191 2, p. 220. 

 Type locality. 'Discovery' Winter Quarters, 130 fathoms, McMurdo Sound. 



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

 One immature example of 5 mm. height; the holotype is recorded as 13 x7 mm. Thiele (19 12) 

 recorded an example 4 mm. in height from Gauss Station. 



Genus Diaphana Brown, 1827 



„ , , . /o 1 ix Type: Retusa minuta Brown 



Diaphana paesslen (btrebel) Jr 



Retusa paessleri Strebel, 1905 b, p. 577, pi. 22, figs. 34, 34a. 

 Type locality. Patagonia. 

 St. 51. Off Eddystone Rock, East Falkland Is., from 7 miles N 50 E to 7-6 miles N 63° E of Eddystone Rock, 

 4 May 1926, 115 m. 



