9 o DISCOVERY REPORTS 



On shell characters the Magellanic nordenskjoldi, modestulum and anderssoni appear respectively to 

 belong to distinct groups, but there is scarcely any difference in dentition between nordenskjoldi and 



modestulum. 



There is insufficient comparative material available to me properly to evaluate the differences 

 indicated by the dentition, so for the present the Magellanic members are retained in Calliostoma 

 (sensu lato). 



Calliostoma nordenskjoldi Strebel 



Calliostoma nordenskjoldi Strebel, 1908, p. 66, pi. 1, figs. 5, 5 a, b. 



Type locality. Coast of northern Argentina, 37 50' S, 56 11' W, 100 m. 

 St. WS 776. Gulf of St. George, Patagonia, 46 18' 15" S, 65 02' 15" W, 3 Nov. 1931, 107-99 m - ( one uvin g 

 example). 



Dentition. Fig. H, 22, p. 190. (c» + i) + 4+i+4 + (i + oo). The central tooth of the radula in the 

 above species, coppingeri, modestulum and the new genus Photinastoma, differ from that of typical 

 Calliostoma in having a narrow and deep base. The laterals in this group are elaborately foliated and 

 attached to their bases by slender extensions like ' goose-necks '. The central tooth in nordenskjoldi is 

 distinctive, in that although most of the tooth is narrow it suddenly widens at the base. 



Calliostoma modestulum Strebel 



Calliostoma modestulum Strebel, 1908, p. 70, pi. 1, figs. 13 a, b. 

 Calliostoma modestulum Melvill & Standen, 191 2, p. 347. 



Type locality. South of Falkland Is., 52 29' S, 6o° 36' W, 197 m. 

 St. 1321. From 4 miles S 72 W of East Tussac Rock, Cockburn Channel, to 5-6 miles S 75 W of East Tussac 



Rock, Tierra del Fuego, 16 Mar. 1934, 66 m. 

 St. WS 72. North of Falkland Is., 51 07' S, 57° 34' W, 5 Mar. 1927, 79 m. 



St. WS 80. North-west of Falkland Is., 50 58' 8,63° 39' Wt.050 55' 30" 8,63° 36' W, ^Mar. 1927, 152-156 m. 

 St. WS 81. 8 miles N ii° W of North I., West Falkland Is., 19 Mar. 1927, 81-82 m. 

 St. WS 212. North of Falkland Is., 49 22' S, 6o° 10' W, 30 May 1928, 242-249 m. 

 St. WS 225. North-west of Falkland Is., 50 20' S, 62 30' W, 9 June 1928, 162-161 m. 

 St. WS 243. Between Falkland Is. and Patagonia, 51 06' S, 64 30' W, 17 July 1928, 144-141 m. 

 St. WS 250. North of Falkland Is., 51 45' S, 57 W, 20 July 1928, 251-313 m. 

 St. WS 750. North-east of Falkland Is., 50 50' S, 57 15' 13" W, 18-19 Jan. 1932, 135-144 m. 

 St. WS 877. Off south-west coast of West Falkland Is., 52 35-5' S, 6i° 04' W, 4 Apr. 1932, 350-0 m. 



Range. From 49 22' to 52 29' S and 57 15' 13" to about 65 W in 66-350 m. Falklands area to 

 Tierra del Fuego and Patagonia. 



Dentition. Fig. H, 15, p. 190. (oo + i) + 5 + i + 5 + (i + oo). Central tooth narrow with a deep base, 

 laterals foliated and ' goose-necked '. Innermost marginal massive and hooked with seven strong cusps 

 on its inner distal face and a row of denticles near the outer distal edge. 



Animal. Two long, slender cephalic tentacles and eyes at the end of short stalks at the outer base of 

 each tentacle as in typical Calliostoma. Four pairs of long, slender, epipodial tentacles. 



Calliostoma falklandicum Strebel 



Calliostoma falklandicum Strebel, 1908, p. 69, pi. 6, fig. 89 a-^. 



Type locality. Port Albemarle, Falkland Is., 52 9' S, 6o° 33' W, 15 m. 



St. WS 97. North-west of Falkland Is., 49 S, 62 W to 49° 01' S, 6i° 56' W, 18 Apr. 1927, 146-145 m. 

 St. WS 225. North-west of Falkland Is., 50 20' S, 62 30' W, 9 June 1928, 162-161 m. 

 St. WS 237. North of Falkland Is., 46 S, 6o° 05' W, 7 July 1928, 150-256 m. 



