51 

 var. plicifera n. var. PL III, fig. ']b. 



Shell with radiating plicae, corresponding to the nodules, and with a conspicuous raised 

 line below the infrasutural keel, and between the peripheral and infraperipheral keels, and 

 below this last. 



The radula has a rhachidian tooth (R) with a quadrangular body, the basal corners are 

 much wider apart, than the upper ones, the sides being expanded, the basal margin is rounded, 

 the cusp triangular, with about 4 denticles on each side of the median cusp ; the body of the 

 first (i) and second (2) laterals are subquadrate, the cusp of the first, with about 6, of the 

 second, with about 9 denticles, the third lateral (3) is broader and has a simple cusp. The 

 fourth (4) is elongated, with serrated edges, the fifth tooth (5) is quadrangular without distinct 

 cusp, the uncini are long, slender and simple, they cover the fifth lateral, which may exist in 

 many other species. 



The nearest ally of this species is 5. infralaevis v. Martens (Die beschalten Gastropoden 

 der deutschen Tiefsee-Expedition, 1898 — 99, p. 123, PL IV, fig. 21) but that species is '^uiarga- 

 ritacea, unicolor\ mtitabilis partly rose-coloured; infralaevis is smooth in the interstices of the 

 keels and on the base, the umbilicus is much smaller than in mutabilis^ and has smooth walls, 

 the canal at the suture, not mentioned in the diagnose, is much narrower. 



4. Solariella marginata n. sp. PL III, fig. 8. 



Stat. 102. 6°4'.i N., I20°44'E. 535 M. Fine, yellow sand, i Spec. 



Shell depressedly-conoidal, smooth, shining, grey, umbilicate. Tlie only specimen, which 

 is slightty broken, has 4^3 whorls. Nucleus smooth, followed by about 2 whorls, sculptured by 

 spiral lirae, 6 in number on the third whorl, these lirae become fainter on the fifth whorl, where 

 they are crossed by concentric ribs, beaded where they cross the lirae; last whorl smooth, with 

 microscopic growth-striae, angular at the periphery; near the suture runs a flat cord, which is 

 crenulated by short plicae, about 25 in number; base slightly convex, smooth, with strong- 

 radiating plicae round the umbilicus, each with a separate bead bordering the umbilicus, which 

 is moderately wide, funnel-shaped, pervious, with fine spiral lirae and concentric plicae, crossing 

 and interrupting them. Aperture broken, subtriangular, with convex upper and basal margins, 

 columella rather straight, with a conspicuous angle near the basal margin. 



Alt. 4Y0, diam. maj. probably about 6^\, Mill. 



This species is evidently allied to S. biradiahila v. Martens (Die beschalten Gastropoden 

 der deutsch. Tiefsee-Exp. 1898 — 99, p. 123, PL V, fig. 3), but may be easily distinguished by 

 the sculpture of the upper whorls, and the beads of the plicae, bordering the umbilicus; these 

 plicae are stronger and longer. 



Subg. Ethaliopsis n. subg. 



Shell depressed-conical, beaded near the suture, polished, umbilicus partly or entirely 

 covered by a callus. Operculum horny, with numerous narrow whorls. 



SI 



