SYSTEMATIC 127 



Type localities. 'Tranquebar et insulas Falkland' (trochiformis) ; Peru and Chile (radians); 

 Patagonia (costellata). 



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. 

 St. WS 88. Off Tierra del Fuego, 54 S, 64 57' 30" W, 6 Apr. 1927, 118 m. 



St. WS 92. Between Falkland Is. and Patagonia, 51 58' 30" S, 65 01' W, 8 Apr. 1927, 145-143 m. 

 St. WS 841. Burdwood Bank, 54 n' 45" S, 6o° 21' 30" W, 6 Feb. 1932, 1 10-120 m. 



Dentition. Fig. J, 40, p. 192. St. WS 92. 



Gay (1854, Hupe, p. 232) recognizes both trochiformis ( = radians) and costellata, the former with a 

 range from Peru to Chile and the latter in the Strait of Magellan. 



If two species are represented, it is important to ascertain the correct type locality for trochiformis, 

 which is quoted as 'Tranquebar et insulas Falkland'. Dillwyn's (1817) entry for this species reads 

 'Inhabits the coasts of the Falkland Islands, Favanne. Tranquebar, Chemnitz'. It seems that the 

 Falklands can be assumed to be the type locality and in order to obviate further confusion I nominate 

 these islands as type locality for the radially ribbed Trochita of that area. 



Trochita clypeolum Reeve 



Trochita clypeolum Reeve, 1859, pi. 3, fig. 14. 

 Trochita clypeolum Rochebrune & Mabille, 1889, vi, p. 37. 

 Calyptraea costellata form clypeolum Melvill & Standen, 1907, p. 100. 

 Calyptraea costellata clypeolum Strebel, 1906, p. 159, pi. 13, fig. 93a, b. 



Type locality. Strait of Magellan. 

 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. 

 St. 1 32 1. From 4 miles S 72 W to 5-6 miles S 75 W of East Tussac Rock, Cockburn Channel, Tierra del Fuego, 



16 Mar. 1934, 66 m. 

 St. WS 85. 8 miles S 66° E of Lively I., East Falkland Is., 25 Mar. 1927, 79 m. 

 St. WS 86. Burdwood Bank, 53° 53' S, 6o° 34' 30" W, 3 Apr. 1927, 151m. 



St. WS 92. Between Falkland Is. and Patagonia, 51 58' 30" S, 65 01' W, 8 Apr. 1927, 145-143 m - 

 St. WS 93. 7 miles S, 8o° W of Beaver I., West Falkland Is., 9 Apr. 1927, 133 m. 

 St. WS 97. North-west of Falkland Is., 49 00' 30" S, 6i° 58' W, 18 Apr. 1927, 146 m. 

 St. WS 214. North of Falkland Is., 48 25' S, 6o° 40' W, 31 May 1928, 208 m. 

 St. WS 221. Off East Patagonia, 48 23' S, 65° 10' W, 4 June 1928, 76 m. 

 St. WS 231. North of Falkland Is., 50 10' S, 58 42' W, 4 July 1928, 167-159 m. 

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



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

 St. WS 244. West of Falkland Is., 52 S, 62 40' W, 18 July 1928, 253 m. 



St. WS 871. North of Falkland Is., from 50 29' S, 58 52' W to 50 31' S, 58 48' W, 6 Nov. 1931, 148 m. 

 St. WS 813. Off East Patagonia, 51 35' 15" S, 67 16' 15" W, 13 Jan. 1932, 106-102 m. 

 St. WS 818. West of Falkland Is., 52 30-5' S, 63 27' W, 17 Jan. 1932, 278-285 m. 



Trochita georgiana n.sp., PI. VII, fig. 22 



Shell small, white, smooth except for irregular concentric growth wrinkles, and covered with a thin 

 pale buff epidermis which slightly overlaps the peristome. Conical, of circular outline, with the apex 

 almost central. Protoconch of 1 \ loosely wound, rapidly increasing whorls, first smooth with a median 

 blunt keel but later developing five spiral ribs, two above and three below the keel. The actual apex is 

 slightly excavated. The protoconch and succeeding whorl form a narrow dome-shaped spire in relation 

 to the last whorl, which is more spread. The shell is very similar to that of clypeolum except for the 

 outline of the septum, which is only weakly sigmoid, the outer sinus being only slightly developed. It 



