16 P. A. OYEN. M.-N. KI. 
sion! [ directed special attention to the great importance of this biolo- 
gical fact. 
Macoma sp. Six specimens were found that were much alike to 
M. torelli Srexsrr., but, it is to be regarded as an intermediate type 
between JM. calcaria and M. torelli. The relative shape of this variety 
may be seen from the meassurement of a typical specimen, length 17 mm. 
and height r2 mm. Two additional specimens, that might perhaps be 
regarded as M. calcaria CHEMN., var., were measured, length 20 mm. 
height 16,5 mm., and length 17,5 mm., height 14 mm. respectively; they 
were, however, much alike to the above mentioned intermediate type. 
Mya truncata L. occurred as well in forma typica as in var. udde- 
vallensis, the shells differing very much as well in thickness as in shape, 
being either more straight or more oblique. Biometrical values are, 
Length Number Per cent 
KO 20 DT our uy o 2 1,6 
20—30 » qs 14 7,4 
30—40 » HE: SE RASER 58 30,9 
40—50 » petu e adus 88 46,8 
50—60 » "A eee ee 24 12,8 
69 » A ror ay I 0,5 
Panopea norvegica SpencL. had a rather thin shell of length 38 mm. 
Saxicava pholadis L., as a rule, occurred in rather juvenile specimens 
being often much distorted. Biometrical values are, 
Length Number Berzcent 
rom. ee A 309 21,5 
IO—20 » EV suse 863 60,0 
gu) "Mv S rn 197 12,3 
30—40 » rt crm 85 5,9 
4O—44 » 5 0,3 
Zirphaea crispata L. Of this species only one single specimen was 
found of length 50 mm. 
Tectura virginea Mii. forma typica of length 9 mm. 
Tectura rubella Fagr. var. This species, or variety, had a length 
of 5—9 mm. 
Lepeta caeca Mitt. The occurrence of this species has been de- 
scribed above. Maximum length of the shell was r2 mm. 
Puncturella noachina L. The length of this shell was 11,5 mm. 
' 1 P. A, Oyen: Kvartergeologisk profil gjennem Jarlsberg fra Tønsberg til Ekern, roro, 
pp. 6, 7. 
