SYSTEMATIC I23 



Lamellaria sp. A 



The examples recorded below are probably L. fuegoensis Strebel (1906), but owing to hardening of 

 the animal in alcohol and the extreme fragility of the shell I was unable to extract any shells intact. 

 Dentition. Fig. J, 53, p. 192. St. WS 867. The central tooth is the characteristic saddle-shape, but 

 the cusps are very poorly developed. The laterals are massive, of typical shape, and bear prominent 

 denticles along the upper and lower cutting edges. 



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

 St. WS 867. Between Falkland Is. and Patagonia, 51 10' S, 64 15-5' W, 29 Mar. 1932, 137-144 m. 



Lamellaria elata Strebel 



Lamellaria elata Strebel, 1906, p. 146, pi. 11, fig. 72. 

 Type locality. Puerto Condor, Patagonia. 

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



Dentition. Very similar to that of 'sp. A'. Central tooth saddle-shaped with a broad, short, 

 central cusp and five denticles on each side of it. Laterals massive and hooked with prominent denticles 

 along both the upper and lower cutting edges. 



Genus Marseniopsis Bergh, 1886 



Type (Thiele, 1929): Marseniopsis pacifica Bergh 



Marseniopsis pacifica Bergh 



Marseniopsis pacifica Bergh, 1886, p. 19, pi. 1, figs. 7-27. 



Type locality. Kerguelen I. 



St. 42. Off mouth of Cumberland Bay, South Georgia, 1 Apr. 1926, 120-204 m. 



St. 167. Off Signy I., South Orkneys, 60° 50' 30" S, 46 15' W, 20 Feb. 1927, 244-344 m - 



St. 190. Bismarck Strait, Palmer Archipelago, 64 56' S, 65 35' W, 24 Mar. 1927, 93-130 m. 



Dentition. Formula 2+1 + 1 + 1 + 2. The central tooth is narrow with a deep entire base, not 

 saddle-shaped as in Lamellaria, and there is a long, narrow, central cusp with four denticles on each side. 

 The lateral is massive and hooked with four serrations near the lower cutting edge. In addition, there 

 are paired smooth slender marginals. The radula in a St. 190 example is exactly as figured by Bergh. 



Unfortunately, the specimens were too contracted and hardened to extract the shell, but since the 

 figured central tooth of both murrayi Bergh, 1886, and conica Smith (Eales, 1923) are very different in 

 shape and detail, I have no hesitation in assuming that the 'Discovery' material represents Bergh 's 

 pacifica. Further, the dorsal surface of the animal in the material listed above is covered with depressed, 

 rounded tubercles exactly as in Bergh 's description of pacifica. 



Family TRICHOTROPIDAE 

 Genus Antitrichotropis n.g. 

 Type: Trichotropis antarctica Thiele, 19 12 

 The above new genus is necessary for the Antarctic species recorded below, which differ from the 

 boreal Trichotropis in being depressed turbinate and in having simple lateral teeth without denticles. 



Antitrichotropis antarctica (Thiele) 



Trichotropis antarctica Thiele, 19 12, p. 197, pi. 12, fig. 6. 

 Trichotropis antarctica Smith, 1915, p. 67, pi. 1, fig. 6. 

 Trichotropis antarctica Hedley, 1916, p. 50. 



