8 N. ODHNER, NORTHERN AND ARCTIC INVERTEBRATES. VI. PROSOBRANCHIA. 2 SEMIPROBOSCIDIFERA . 



inside it, Colour whitish or browiiish; döts brown, more or less conspic- 



uous. H. 9 — 18 mm L. nitida (Donovan 1800) 



(=Natica piilchella Risso 1826, N. intermedia Philippi 1836, 



N. Alderi Forbes 1838). 



Pl. 4 Fig. 21; n. 5 Fig. 20. 

 2. Whorls inflated, with deep suture, coloured with one siibsutural row of 

 brown döts; upper angle of the aperture with a thin expanded callus, se- 

 parated from the outer Hp by a broad sinus; iimbilicus with some shght 

 spiral grooves within. Colour hglit brownish, döts darker brown. H. max. 

 aboiit 30 mm L. catena (Da Costa 1778) 



(= Natica monilifera Lamarck 1822). 



Pl. 4 Figs. 19, 20. 



B. Shell iinicoloured, brownish, often with a whitish band at the suture; whorls 

 inflated, suture deep; umbilicus contracted by a median callosity of the colu- 

 mellar margin and grooved with one deep spiral furrow; upper angle of the 

 aperture with a slightly projecting callus. Median tooth of the radula usually 

 comparatively narrow (its length usually ^ V2 its breadth). H. 10 — 14 mm 



L. Montagui (Forbes 1838). 



: • . Pl- 4 Figs. 16—18; Pl. 5 Fig. 21, 



IT, Tinier uncini of the radula having cusps of uniform size; shell always unicoloured. 



A, Umbilicus nearly wholly filled with a callous dilatation of the columella; shell 

 ovate globose, whorls but slightly convex with a shallow suture, smooth or 

 with inconspicuous spiral lines. Colour white or yellowish brown. Median tooth 

 of the radula comparatively narrow (its length > V2 breadth). H. about 5 mm 



-, ■- - , :; - - L. nana (Möller 1842). 



Pl. 4, Figs. 22—25. 



B. Umbilicus narrow, more or less contracted by the reflected columellar margin, 

 but not filled with callus; shell globose. 



1. Shell smooth or with undefined spiral lines; outer lip and lines of growth 

 (seen from spire) somewhat concave and produced, inserted tangentially 

 on the body whorl; usually a blunt cord or ridge below the suture. Co- 

 lour greenish, yellowish or brownish. Animal light yellowish. H. of the 

 shell 15 — 40 mm L. palhda (Broderip & Sowerby 1829) 



■ (= Natica groenlandica Möller 1842). 



Pl. .3 Figs. 1.5, 19—37; Pl. 4 Figs. 1—8; Pl. 5 Figs. IG— 18. 



2. Shell with fine impressed undulating spiral lines; whorls regularly convex 

 without subsutural ridge; outer lip and lines of growth, as seen from spire, 

 somewhat convex and inserted at an obtuse angle on the body whorl. 

 Colour yellowish or reddish brown. Animal with the foremost part of the 

 mantle blackish. H. of the shell 30 — 15 mm. 



L. tenuistriata Dautzenberg & Fischer 1911 

 (=? Bulbus Smithii Brown 1838). 



Pl. 4 Figs. 9—15; Pl. 5 Figs. 19 



