SYSTEMATIC 97 



Margarella steineni (Strebel) 



Margarita (Photitiula) expansa Martens & Pfeffer (non Sowerby), 1886, pi. 2, figs. ioa, c. 

 Photinula steineni Strebel, 1905, p. 158, pi. 5, figs, iba-d. 

 Photitiula steineni Strebel, 1908, p. 73. 

 Margarella steineni L. David, 1934, p. 127. 



Type locality. South Georgia. 



St. 141. East Cumberland Bay, South Georgia, 200 yards from shore, 29 Dec. 1926, 17-27 m. 



St. 145. Stromness Harbour, South Georgia, 7 Jan. 1927, 26-35 m - 



St. WS 25. Undine Harbour (North), South Georgia, 17 Dec. 1926, 18-27 m - 



Range. South Georgia, 0-35 m. 



A small, pale cream-coloured shell, pearly externally, and greenish iridescent inside the aperture. 



Margarella jason n.sp., PI. V, fig. 1 



A pale cream, pearly shell with pale iridescent interior to the aperture. Whorls four, rapidly increasing. 

 Spire half height of aperture, suture plain, tangential to slightly adpressed over last half-whorl. 

 Columella lip broad, slightly concave, rapidly contracted below to the thin-edged basal outer lip. 

 Outer edge of columellar callus sharp, outwardly curved and partly encroaching upon a crescentic 

 umbilicus, which is incised with four concentric narrow grooves. Operculum normal, horny, with 

 a central nucleus. 



This new species resembles antarctica (Lamy, 1905), but differs in reaching only half the linear 

 dimensions, in having a much smaller umbilicus, incised with grooves, a broadly expanded columellar 

 callus and more rapidly increasing whorls. Both species have the whorls rather narrowly rounded at 

 the periphery. 



Major diameter 6-o mm. ; minimum diameter 5-0 mm. ; height 4-5 mm. (holotype). 



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



This species is almost certainly a benthic relative of Strebel's Margarita subantarctica (1908, p. 76). 

 Strebel's species is based upon juveniles (14X i-2mm.) from low water, Cumberland Bay, South 

 Georgia. The smooth unicoloured Margarella forms are difficult enough to separate even as adults. 

 It is possible that when fully grown littoral shells are found, my jason n.sp. may prove to be a synonym 

 of subantarctica, but, on the other hand, it is unlikely that shells from such different habitats will be 

 identical. Thiele (1912, p. 258) included subantarctica in the synonymy of antarctica. For the present 

 Strebel's species is best considered indeterminate. 



Margarella bouvetia n.sp., PI. V, fig. 3 



Shell small, white, with a faint iridescence. Turbinate, thin, of 4! rounded whorls. Spire three- 

 fifths height of aperture. Suture impressed, not margined. Columellar callus moderately wide medially, 

 rapidly contracted below to the thin-edged basal outer lip, and above, partly bridging a deep open 

 umbilicus. Umbilicus about one-tenth major diameter of shell, sculptured between the outer area of 

 the umbilicus and the base with nine deeply incised spiral grooves. Eight of these grooves are closely 

 spaced, but the outermost is double-spaced. The rest of the shell is smooth, except for weak, distant, 

 irregular, axial growth lines which become concentrated within the umbilicus. Operculum horny with 

 a central nucleus. 



Dentition. Fig. G, 8, p. 189. 



Major diameter 8-4 mm. ; minimum diameter 7-0 mm. ; height 7-5 mm. (holotype). 



Major diameter 9-0 mm. ; minimum diameter 7-8 mm. ; height 8-o mm. (largest). 



Type locality. St. 456. 1 mile east of Bouvet I. 18 Oct. 1930, 40-45 m. 



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