1912. No. 8. THE QUATERNARY SECTION OF KILEBU. 15 
Length Number Per cent 
SENERE a SES I 4,2 
10—15 » uw o4 16,7 
15—20 » ‘ : 4 16,7 
3 365 > 8 33.4 
2 
ir Po DC ar EEE 29 
Only one single specimen had a length of 30 mm. One specimen 
of length 12 mm. with very prominent concentric striæ and a very thin 
ventral edge belongs to quite the same type as one specimen of length 
7 mm. having been found in a shell-bank near Aas and having there 
been regarded as A. sulcata pA Costa var. scotica JEFFR. 
Axinus flexuosus Mont. This species was found as well in forma 
typica (VI) as in a variety approaching to A. sarsit Pan. (VIII), but it 
did not occur in the material of the biometrical analysis. 
Azinus sarsii Pum. only occurred as one single specimen of length 
7 mm. 
Abra longicallis Sc. var. This species occurred in a variety ap- 
proaching somewhat to A. alba Woop. Length 10 mm. 
Macoma calcaria Cuemn. forma typica. It may, however, be especi- 
ally noted, that some of the specimens are in such a way divergent from 
the normal type as to constitute special variants. One specimen of 
length 28 mm. was very similar to the variety, which I have described 
on a former occasion! and, moreover, it was highly interesting to find 
transitional types of length 30 mm. and 33 mm. A special oblique type 
approaching to M. sabulosa was not rare, measuring a length of 17—21 mm. 
Biometrical values are, 
Length Number Per cent 
IO—15 mm 5 1,2 
15—20 » zog E. 54 13,0 
20—25 » SOUL ERE E AS 48,6 
25—30 » 134 32,2 
30—35 » TUE "gr 20 4,8 
37 » NOn oe I 0,2 
From this table we get a clear conception how erroneously it is to 
draw conclusions as to the flourishing condition of a species from the 
mere maximum length of the same. The very same feature is to be 
seen from each one of such biometrical tables. And, on a former occa- 
1 P. A. Oyen: Contributions to the Quaternary Geology of Norway. I (1911), p. 5. 
