SYSTEMATIC 125 



Genus Neoconcha Smith, 1907 

 Neoconcha vestita Smith T yP e ( monot yPy) = Neoconcha vestita Smith 



Neoconcha vestita Smith, 1907a, p. 6, pi. 1, figs. 11-iic. 

 Neoconcha vestita Smith, 1915, p. 68, pi. 1, fig. 8. 

 Neoconcha vestita Eales, 1923, p. 11. 



Type locality. Off Coulman I., 100 fathoms, Ross Sea. 



St. 1652. Ross Sea, 75 56' 2" S, 178 35' 5" W, 23 Jan. 1936, 567 m. 

 Major diameter 7 mm. ; height 8 mm. (holotype). 

 Major diameter 28 mm. ; height 23 mm. (Smith, 1915). 

 Major diameter 17-5 mm.; height 17 mm. (St. 1652). 



Dentition. Figured by Eales (1923, loc. cit. p. 12, fig. 9). 



The buff-coloured epidermis is like a heavy coating of cotton-wool. 



Genus Discotrichoconcha n.g. 

 Type : Discotrichoconcha cornea n.sp. 

 This new genus is considered necessary for a small species of the same horny shell substance as 

 Trichoconcha but much smaller, paucispiral and discoidal, being vertically compressed like the fresh- 

 water genus Planorbis. The few rapidly increasing whorls coupled with the extreme compression of the 

 shell results in a curious broad, very shallow, rectangular aperture. 



The only example is too fragile to attempt extracting the animal, which is retracted so much that the 

 operculum is not visible. Its great departure in shape and small size compared with Trichoconcha seems 

 to warrant generic separation. 



Discotrichoconcha cornea n.sp., PI. VII, fig. 21 



Shell small, horny, discoidal-planorbid, of 2| whorls, including a blunt, low, rounded, microscopically 

 spirally striated protoconch of one whorl. Spire slightly sunken ; umbilicus broad, open, about one- 

 fifth diameter of base, showing all the whorls, even the protoconch. Sculpture consisting of dense 

 arcuate lamellar epidermal processes, each set with numerous short, hair-like filaments. Colour 

 yellowish brown. The aperture is reflected over the parietal wall and slightly dilated all round ; the 

 shape is rectangular, about three times wider than high. 



Major diameter 5-3 mm. ; minimum diameter 4-0 mm. ; height 17 mm. 



Type locality. St. 182. Schollaert Channel, Palmer Archipelago, 64 21' S, 62 58' W, 14 Mar. 

 1927, 278-500 m. (holotype only). 



Family CREPIDULIDAE 

 Genus Crepipatella Lesson, 183 1 



Type : Crepidida dilatata Lamarck 

 Crepipatella dilatata (Lamarck) 



Crepidida dilatata Lamarck, 1822, p. 25. 

 Crepidula pallida Broderip, 1835, p. 204. 



Crypta subdilitata Rochebrune & Mabille, 1889, p. H 37, pi. 4, fig. II. 

 Crepidula dilatata Strebel, 1906, p. 166, pi. 12, fig. 87a, b; pi. 13, figs. 100a, b, 101 a, b. 

 Crepidula dilatata Melvill & Standen, 1907, p. 130. 

 Crepidida dilatata Melvill & Standen, 1914, p. 117. 

 Type localities.? (dilatata); Falkland I. [pallida); Orange Bay, Patagonia (subdilitata). 

 St. 55. Entrance to Port Stanley,, East Falkland Is., 2 cables S 24 E of Navy Point, 16 May 1926, 10-16 m. 



