390 
The two distinguishing characters on the radula seems to be 
considerabl}^ less constant on the Icelandic specimens which 
I have examined. I noticed here a variation as follows: 
A. In 8 specimens of Buccinum undatum, from Eeykjavik, with 
verj well developed longitudinal folds: 
1 specimen 5—6—4 (Fig. I) 
3 
1 
1 
1 
1 
15 
55 
55 
55 
4_6—4 
4—5—4 
4—7—3 
4—6—3 
3—7—3 
(Fig. II) 
(Fig. III) 
B. In 25 specimens (from Reykjavik and Stykkisholm) of a 
little littoral, purplish olive-green coloured Buccinum with 
small or moderately well developed longitudinal folds. 
Verkriizen^) named this form: Buccinum undatum var. 
planum. It depends on a pure individual point of view 
whether the specimens with small longitudinal folds are 
reckoned to B. uiidatum or to B. groenlandicum\ 
1 specimen 4 —9 —4 (Fig. lY) 
1 
10 
2 
2 
1 
1 
1 
3 
1 
1 
1 
55 
55 
55 
55 
55 
55 
55 
55 
4 —7 —4 
4 _6 —4 
4 —5 —4 
4—6—3 (Fig. V) 
4 —5 —3i 
4 _5 _3 
3i —6 —3i 
3 _6 —3 
^2 ^ ^ ^ \ longitudinal folds 
3 —4 —4 I very indistinct 
3 —32—3 
T. A. Verkriizen; „Dredging-Excursion to Iceland‘‘ etc. Ann. & 
Mag. Nat. Hist. IV Ser. vol. 10. 1872. 
