378 Messrs. R. M'Andrew and L. Barrett's List of the Mollusca 



XXXIII. — List of the Mollusca observed between Drontheim 

 and the North Cape. By R. M'Andrew, Esq., F.L.S., and 

 L. Barrett, Esq., F.G.S. 



Our observations extended along 700 miles of coast, 300 of 

 which were south and 400 north of the arctic circle, and from 

 the littoral zone to a depth of 200 fathoms. The opportunities 

 for dredging were most favourable, the coast being protected 

 from the Atlantic swell by the numerous islands to the seaward ; 

 and the deeply indented fiords supplying many secure anchorages 

 and sheltered dredging grounds. In the following lists the 

 Norwegian distribution of each species is given, the coast being 

 divided into three provinces, so that the extreme southern limit 

 of the arctic species, and the northern limit of the southern spe- 

 cies, can be more correctly ascertained. 



Gasteropoda. 



We met with 103 species of this class ; of these 91 belong to 

 the order Prosobranchiata, and 12 to the Opisthobranchiata. The 

 smaller species were extremely abundant, but the larger species 

 of Buccinum and Fusus were seldom met with. 



Prosobea^nchiata. 



A'o^e.— The figures in the first column of this and the following pages 

 mdicate the extent of the range at which the species was met with, whether 

 alive or dead ; in the second, the greatest and least depth at which it was 

 dredged alive ; in the thii-d, the kind of sea-bottom is named ; in the fourth, 

 the letters express the degree of frequency of occurrence : — a. abundant, 

 generally distributed and plentiful ; /. frequent ; /. local, more or less plen- 

 tiful in a few localities ; r. rare ; and v. r. very rare, when but few ex- 

 amples occurred. In the fifth column the northern Scandinavian distri- 

 bution is given, the coast being dudded into three unequal provinces : 

 North Drontheim (Dront.); Nordland (Nord.) ; and Finmark (Fin.). 



