, so DISCOVERY REPORTS 



Proneptunea duplicarinata n.sp., PI. VI, fig. 13 



Shell small, fusiform, thin, covered with a pale yellowish brown epidermis, prominently sculptured 

 with heavy spiral keels, the main ones divided into two or three by linear grooves, and crossed by 

 distant fringe-like axial epidermal processes. Whorls five, including a relatively large, smooth, pauci- 

 spiral protoconch of two straight-sided whorls, the top concave, oblique, with a slightly inrolled nucleus. 

 Spire slightly less than height of aperture plus canal. First post-nuclear whorl sculptured with three 

 prominent spiral keels, the uppermost, at about three-fourths whorl height, defining a broad, slightly 

 concave shoulder. Second post-nuclear whorl with both the uppermost and lowest keels bifid and 

 penultimate with the uppermost and lowest trifid and the middle one bifid. Body-whorl with the same 

 development as the penultimate plus another bifid keel, level with the top of the aperture, six simple, 

 widely spaced spirals on the base and neck, and six closely spaced, weak spiral cords on the fasciole. 

 Axials in the form of fringe-like epidermal lamellate processes, eleven per whorl. The lamellae are 

 regularly deeply scored, causing them to split into a series of moderately long, narrow tags. Aperture 

 broadly ovate but produced below into a relatively long, obliquely recurved anterior canal. Outer lip 

 thin, corrugated by the external sculpture and deeply spirally scored within. 



Height 17-0 mm. ; diameter 7-0 mm. 



Type locality. St. 160. Between South Georgia and Shag Rocks, 53 43' 40" S, 40 57' W, 



7 Feb. 1927, 177 m. 



Dentition. Fig. K, 66, p. 193. 



Genus Chlanidotella Thiele, 1929 



Type (monotypy) : Cominella modesta Martens 



Chlanidotella modesta (Martens) 



Cominella modesta Martens, 1885, p. 91. 



Cominella modesta Martens & Pfeffer, 1886, p. 73, pi. 1, fig. \a-e. 



Chlanidota modesta Strebel, 1908, p. 33. 



Thalassoplanes (Chlanidotella) modesta Thiele, 1929, p. 317. 



Chlanidota (Chlanidotella) modesta David, 1934, 2-3, p. 128. 



Type locality. South Georgia. 

 St. WS 56. Larsen Harbour, Drygalski Fjord, South Georgia, 14 Jan. 1927, 2 m. 



St. MS 10. East Cumberland Bay, \ mile south-east of Hope Point to \ mile south of Government Flagstaff, 

 14 Feb. 1925, BTS, 26-18 m. 

 Range. South Georgia, 0-18 m. 



Dentition. Fig. L, 80, p. 194. The laterals bear four cusps, evidently the result of regular bifurcation 

 of an original two. The central tooth has the usual three cusps of the family, but the basal plate is deeper 

 than in either Chlanidota or Pfejferia. The operculum has a terminal nucleus. 



Family MURICIDAE 



The dentition of the southern Trophons does not present any clear-cut types. In fact, the radulae of 

 both the Muricidae and the Thaisidae conform remarkably to a single type which presents only minor 

 variations. The protoconch, however, clearly divides the southern Trophons into two main groups: 

 (1) with a paucispiral asymmetrical nucleus and (2) with a polygyrate conical nucleus. 



The Trophons are members of the Muricidae because they have an operculum with a terminal or 

 subterminal nucleus and a rounded, not flattened or excavated columella. The members of the Thaisidae, 

 on the other hand, have an operculum with a lateral nucleus and the columella is definitely flattened to 

 excavated. Muricids are mostly lightly built with lamellate to spinose sculpture and a long anterior 

 canal. Thaisids, on the other hand, are usually solid, ovate, with rugged sculpture and relatively short 

 anterior canal. 



