KUNGL. SV. VET. AKADBMIENS HANDHNGAR. BAND 48. N:0 1. 



11 



Uniformly cream-coloured; radiating lines distinct. L. 10—11 mm 



var. spitzbergensis n. var. 



PI. 1 figs. 14—15. 



2. Shell of a uniform reddish, brownish or yellowish colour, without radiat- 

 ing sculpture. L. 4 — 8 mm A. rubella (Fabricius 1780). 



PL 1 tigs. 16—23. 



Shell elevated conic with concave under side var. elevata Odhner 1910. 



PI. 1 fig. 2,3. 



II. Radula with a rudimentary uncinus on each side, at least in certain segments: 

 1 . 2. (1 .0 . 1 .) 2 . 1; all teeth pointed (subg. Collisella Dall 1871). 



A. Second lateral tooth elongated conical, about 4 times the third in length, 

 slowly tapering towards the apex. Shell smooth or with fine radiating strise, 

 apex directed foreward, hind slope slightly convex; colour: white and brown 

 stripes of about equal breadth; inside bluish with a well defined brown 

 centre and a broad white-striped brown marginal band. L. 24—34 mm 



A. patina Eschscholtz 1833. 



PI. 1 fig. 8 



B. Second lateral tooth about 2 times the third, from a quadrangular base 

 abruptly tapering towards the apex. Shell smooth or with strong radiating 

 ridges; apex directed foreward, hind slope highly convex; colour: irregular 

 brown and white stripes and minute white and black dots; inside with an 

 undefined brown centre (or spots), a bluish or whitish lateral partition and 

 a dark marginal zone often with irregular white and brown dots. L. 11 — 25 

 mm A. persona Eschscholtz 1833. 



C. Second lateral tooth nearly as long as the third, triangular, thus immediately 

 from the base-line tapering towards the pointed apex. Shell conic with 

 coarse radiating ridges, often obsolete, hind slope nearly straight; colour: 

 brown stripes broader than the white ones; inside cream coloured with 

 an irregularly brown-spotted centre and a narrow discontinuous marginal 

 band of brown dots. L. 30—40 mm A. pelta Eschscholtz 1833. 



PI. 1 fig. 8; PI. 6 fig. 2. 



Fam. Patellidae. 



I. Radula 3 . 1 . (2 . . 2) . 1 . 3 ; branchiae in a complete circle; shell solid with the 

 apex nearly central Patella Linne 1758. 



II. Radula of the same formula; branchial circle interrupted in front; shell thin, 

 with the apex anterior Helcion Montfort 1810. 



Patella Linne 1758. 



Surface of the shell with radiating ribs (sometimes obsolete) and stri». Colour 

 varying: white, yellow, red, greenish or blackish. L. 35—58 mm 



P. vulgata Ltnne 1758. 



PI. 1 figs. 24—26. 



