18 P. A. ØYEN. M.-N. Kl. 
Solberg (L. = 15 mm.)!, Sem (L. = 11 mm.)?. Linddal (L. = 18 mm.)3, 
and Krappeto (L. — 17 mm)", Moreover, one specimen of length i19 mm. 
found by M. Sans near Moen? proves to belong to the very same 
variety. 
Beside the above mentioned pretty fine specimen of forma typica 
twenty three specimens of a juvenile type were found measuring in length 
4,5—9,0 mm. It is often very difficult to decide definitely as to the true 
definition of the species in regard to this small variety. We may, how- 
ever, be rather well justified in regarding them as juvenile individuals of 
L. littorea. As to this determination I might be allowed to state that 
my material] for comparison is much greater than has at any time previ- 
ously been at hand. The whole collection of Littorinas from the shell- 
banks of Aremark, the district in question, was previously only com- 
prising thirty specimens from six different localities, that is, as a mean, 
only five specimens from each place. More than half of this collection 
was my own from six different localities, only one specimen, however, 
being found at Kilebu. My collection made at Kilebu during the last 
summer, however, comprises no less than ninety five specimens of diffe- 
rent species of Littorina. Among those were also found eight speci- 
mens of length 5— 10 mm. of a more globular form, much alike to L. 
rudis Mar., but, a canal at the upper part of the mouth, and the shape 
of the last whorl indicate a variety of L. littorea L. 
Littorina rudis Mar. Of this species forty-four specimens were 
found of length 3,5—8,5 mm. 
Littorina sp., patula Jerrr. of length 5—11 mm. occurred in different 
variant specimens, nineteen in number. The same species with different 
varieties I have described more in detail on a former occasion. 
Lacuna divaricata FaBr. occurred in four specimens of a maximum 
length 8 mm. the biggest specimen being somewhat alike to the variety 
glacialis or arctica. 
Onoba striata Mont. forma typica had a length of 4 mm. 
Onoba aculeus Gourp var. had the unusual length of 6,5 mm. and 
was represented by a very fine specimen. 
1 P. A. Oyen: Kvartærgeologiske streiftog omkring den indre del af Bundefjorden, 1908, 
P. A. Oyen: Sjælbanke-studier i Kristiania omegn, 1907, pp. 48 — 49. 
P. A, Oyen: Kvartar-studier i den sydøstlige del af vort land, 1908, p. 59. 
. OYEN: Kvartær-studier i den sydøstlige del af vort land, 1908, p. 64. 
ao o aD 
T 
5 h 
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Sars: Foss. Dyrelevn. fra Quartærper. Univ.prog. 1864, I, p. 13. 
9 P. A. Oven: Kvartær-studier i Trondhjemsfeltet, II, 1911, p. 170. 
