SYSTEMATIC 93 



near Santa Barbara Islands, 414 fathoms, California. Since the radula of platinum has not been described, 

 actual relationship with georgianus cannot be claimed. 



Type locality. St. 42. Off mouth of Cumberland Bay, South Georgia, from 6-3 miles N 89 E of 

 Jason Lt. to 4 miles N 39 E of Jason Lt., 1 Apr. 1926, 120-204 m. 



Dentition. Fig. H, 16, p. 190. (oo + i)+i6+i + i6+(i + oo). 



Falsimargarita n.gen. 

 Type : Margarites gemma Smith 



Eales (1923, p. 8) gave a good description and figure of the dentition of gemma. This and the allied 

 species iris have the radula of the Calliostomid type, that is, with more or less rectangular-based central 

 and lateral teeth having long curved foliaceous cusps bearing numerous sharp denticles. 



The shell is very thin, white or pale cream, iridescent both externally and internally, elaborately 

 sculptured with fine crisp spirals and axial threads and with a deep but relatively narrow umbilicus. 



This new genus differs from Calliostoma in the thin externally iridescent shell, open umbilicus and in 

 details of the radula. The broad central tooth, more than twice the width of any of the laterals, is 

 a distinctive feature. There is, of course, no relationship to Margarita. 



Falsimargarita gemma (Smith) 



Margarites gemma Smith, 1915, p. 62, pi. 1, fig. 1. 

 Margarites gemma Eales, 1923, pt. 5, p. 8. 



Dentition. Fig. H, 23, p. 190. 



Type locality. Off Oates Land, 180-200 fathoms. 

 St. 175. Bransfield Strait, South Shetlands, 63 17' 20" S, 59 48' 15" W, 2 Mar. 1927, 200 m. 



Major diameter 22-0 mm.; minimum diameter 19-0 mm.; height 18 mm. (holotype). 



Major diameter 17-4 mm. ; minimum diameter 15-0 mm. ; height 15 mm. (St. 175). 



The finding of this superb and rare species on the opposite side of Antarctica from the type locality 

 is of interest. 



The Bransfield Strait specimen agrees in minute detail with Smith's full description and excellent 

 figure, and the radula is exactly as figured by Eales (1923, loc. cit.). The specimen is not quite fully 

 grown . 



Falsimargarita iris (Smith) 



Margarites iris Smith, 1915, p. 91, pi. 2, fig. 4. 

 Margarites iris Eales, 1923, p. 7. 



Type locality. West of Falkland Is., 125 fathoms. 

 St. WS 245. Between Falkland Is. and Patagonia, 52 36' S, 63 40' W, 18 July 1928, 304-290 m. 

 St. WS 818. Between Falkland Is. and Patagonia, 52 31' 15" S, 63 25' W, 17 Jan. 1932, 272-278 m. 

 St. WS 821. Off Falkland Is., 52° 55' 45" S, 6o° 55' 00" W, 18 Jan. 1932, 461-468 m. 



Genus Photinula H. & A. Adams, 1854 

 Type (s.d. Pilsbry 1889), Margarita coerulescens King & Broderip 

 Thiele has shown by his work on Trochoid dentition that Photinula is allied to Calliostoma (Thiele, 

 1906c, pp. 12-15 and 1921, p. 68). 



Photinula coerulescens (King & Broderip) 



Margarita coerulescens King & Broderip, 1831, p. 346, fig. 54. 



Photinula ringei Pfeffer, 1887, p. 133. 



Photinula coerulescens Rochebrune & Mabille, 1889, p. H81. 



