,88 DISCOVERY REPORTS 



whorls consisting of numerous closely spaced, faint, rounded spiral threads, and strong 

 radial folds surrounding the umbilicus. The spiral threads number about forty on the 

 last whorl, and they are slightly more distinct on the upper part. There are thirty axial 

 folds in the holotype and they are strongest where they cross a faintly angular spiral 

 ridge which in turn defines a wide depressed concavity running into the umbilicus. 

 These folds fade out at about half way towards the periphery and also at the umbilicus 

 proper, which is further defined by another angular spiral ridge. Width of umbilicus 

 proper about one-sixth major diameter of base ; umbilical concavity almost two-thirds 

 major diameter of base. Aperture circular. Peristome thin, overhanging above and con- 

 nected across parietal wall by a callous pad. Spire about one-third height of aperture. 



Height i-i mm.; major diameter i-6 mm. (Holotype). 



Habitat: Off Three Kings Islands, St. 933, 260 m. 



Quite distinct from any of the described species in the strongly developed radial 

 umbilical folds. 



Argalista variecostata, n.sp. (Plate L, fig. 17). 



Shell small, solid, turbinate, umbilicate, sculptured with numerous closely spaced 

 spiral cords, and three spiral keels. Whorls 3 1, including minute smooth slightly convex 

 protoconch of one whorl. Spire about two-thirds height of aperture. Umbilicus open, 

 deep, about one-sixth diameter of base, the edge fairly sharp and crenulated by short 

 axial folds. Only two of the spiral keels show on the spire whorls, the third being just 

 below the suture; they are equispaced, rather widely over the middle of the last whorl. 

 The finer spiral cords on the body whorl number nine between the suture and the 

 uppermost keel, followed by eight both between keels 1 and 2 and keels 2 and 3, and 

 finally ten from the lowest keel to the umbilicus. Aperture rounded, typical. Colour of 

 holotype pale pink with very small irregular patches of light brown. Peristome and 

 interior of aperture white. Some paratypes have the ground colour buff. 



Height i-8 mm.; diameter 2-3 mm. (Holotype). 



Habitat: Off Three Kings Islands, St. 934, 92 m.; also St. 933, 260 m. 



This species differs from flnctuata (Hutton, 1883) in having the three keels as well as 

 the finer spiral cords. Also it is quite distinct from crassicostata (Murdoch, 1905), 

 which is sculptured with a few fairly regular strong spiral cinguli. 



Some senile specimens from St. 933 have the three spiral keels much more massive 

 than in the holotype, which represents the normal form. 



Family LEPETIDAE 



Genus Tectisumen, Finlay, 1926 



Type (original designation) : Cocculina clypidellaeformis, Suter 



Tectisumen subcompressa, n.sp. (Plate XLIX, figs. 4, 5). 



Shell small, thin, white, oval, somewhat laterally compressed, conical, ends rounded 

 and upcurved. Nucleus a tiny rounded smooth point inclined slightly forwards and 



