SYSTEMATIC 161 



Swainson, 1832 is C. broderipia Swainson (n.nom. for Voluta cymbiola Swainson. Type by tautonomy). 

 Dall's substitute name Adelomelon, 1906, is therefore the correct genus for the series of Magellan 

 volutes centred around Solander's ancilla. 



Adelomelon ancilla (Solander) 

 {ancilla) 



'Grand Buccin Magellanique', D'Avila, 1767, pi. 8, fig. S, no. 181. 



Voluta ancilla, Solander, 1786, p. 137, no. 3061. 



Voluta magellanica, Chemnitz, 1788, pp. 138-9 (exclusive of figures). 



Voluta spectabilis, Gmelin, 1791, p. 3468. no. 142. 



Voluta ancilla Lamarck, 1816, pi. 385, fig. 3. 



Cymbiola ancilla Pace, 1902, p. 28, pi. 7, figs. 1-16. 



Voluta ancilla Strebel, 1906, pi. 8, figs. 25 (copy of D'Avila's figure), 18, 20, 22, 23; pi. 9, figs. 37, 45, 50, 51. 



Adelomelon ancilla Dall, 1906, p. 143. 



Adelomelon ancilla Dall, 1907, p. 355. 



Adelomelon ancilla Smith, 1942, p. 55, pi. 25, fig. 171. 



(magellanica) 



Voluta magellanica Chemnitz, 1788, pp. 138-9 (in part), figs. 1383, 1384. 



Voluta magellanica Gmelin, 1791, p. 3465, no. no. 



Voluta magellanica Kiener, 1839, pi. 51. 



Voluta ancilla Reeve, 1849, pi. 17, fig. 39. 



Voluta bracata Rochebrune & Mabille, 1889, p. 48. 



Scap/iella (Voluta) arnheimi Rivers, 1891, locality 'Monterey Bay, California' false. 



Voluta ancilla with vars. typica, ponderosa, elongata, expansa and abbreviata Lahille, 1895, p. 311. 



Voluta magellanica Strebel, 1906, pi. 8, figs. 17, 19, 21, 24-32; pi. 9, figs. 36 and 41. 



Adelomelon magellanica Dall, 1907, p. 355. 



Adelomelon magellanica Smith, 1942, p. 57, pi. n, fig. 83. 



(The above is an abridged synonomy.) 



Most of the ' Discovery ' volutes are more or less elongated shells without nodules. Larger series than 

 I have available will be necessary to determine if magellanica is really distinct from ancilla. Variation is 

 considerable, so much so that it is difficult to match individual specimens with the original figures. 

 In several instances ancilla and magellanica forms are present in one dredging station, and more often 

 than not, examples tend to combine in varying degrees the differentiating criteria set out by Dall (1889 a 

 p. 312). Dall stated that ' S. magellanica is much like the S. ancilla from which it is chiefly distinguished 

 by its smaller size, more slender form and usually fewer plaits '. 



Since I am unable to draw a satisfactory line between ancilla and magellanica I have for the present 

 referred the ' Discovery ' material to the prior name. That is all the examples that range between the 

 figure of D'Avila ( 1 767) = ancilla and that of Chemnitz (1788) = magellanica. 

 Type localities. Strait of Magellan (ancilla and magellanica). 

 St. 51. Off Eddystone Rock, East Falkland Is., 4 May 1926, 115 m. 

 St. 1902. Off Santa Cruz, Patagonia, 49 48' S, 67 39-5' W, 28 Nov. 1936, 50-30 m. 

 St. WS 71. 6 mile N 6o° E of Cape Pembroke Lt., East Falkland Is., 23 Feb. 1927, 82-80 m. 

 St. WS 83. 1 4 miles S64°W of George I., East Falkland Is., 52° 28' S, 6o° 06' \Vt052 30' 00" S, 6o° 09' 30" W, 



24 Mar. 1927, 137-129 m. 

 St. WS 109. North of Falkland Is., 50 19' S, 58 27' W to 50° 18' 36" S, 58 30' W, 26 Apr. 1927, 145 m. 

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



shells). 

 St. WS 247. North of Falkland Is., 52 40' S, 6o° 05' W, 19 July 1928, 172 m. 

 St. WS 776. Gulf of St George, Patagonia, 46 18' 15" S, 65 02' 15" W, 3 Nov. 1931, 50-80 m. 

 Range. Argentina, Patagonia, Straits of Magellan and Falkland Is., 0-172 m. 



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