390 
The two distinguishing characters on the radula seems to be 
considerably 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 Reykjavik, with 
very well developed longitudinal folds: 
1 specimen 5—6—4 (Fig. I) 
å 
I 
1 Ny 4—6—3 
E $ 3—7—3 (Fig. IM) 
sg 
In 25 specimens (from Reykjavik and Stykkisholm) of a 
little littoral, purplish olive-green coloured Buccinum with 
small or moderately well developed longitudinal folds. 
Verkrizen!) 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. undatum or to B. groenlandicum: 
1 specimen 4 —9 —4 (Fig. IV) 
1 Må 4 —7 —4 
10 & 4 —6 —4 
Fldsurgsnro sund 
då (eN 4 —6 —3 (Fig. V) 
i 5 4 —5 —3, 
É Sy 4 —5 —3 
1 kg 3,—6 —3, 
3 Sy 3 —6 —3 
1 ” 85—5,—8 Fig.VI rn: longitudinal folds 
FG 3 —4 —4 indistinet 
E 3 
My T. A. Verkrizen: ,,Dredging-Excursion to Iceland" ete. Ann. & 
Mag. Nat. Hist. IV Bel. vol. 10. 1872, 
