332 



p. 28), 1 must maintain that J. Collin is perfectly right when 

 writing: "in most specimens the valves are of the same size, 

 only in a few the margin of the left valve will be found to project 

 quite a little over the right one, still without bending over it« 

 and (under Peden Hoshynsi (non Forbes) Sars = P. imbrifer 

 Loven): «in all very thin shelled Pecten-iovm^ the feeblest valve 

 will yield in the edge when the animal in the agonies of death 

 is strongly shutting the valves. This causes the peculiar con- 

 cavity which runs concentrically with the shell edge, the sculp- 

 ture conditions on the right shell imparting this with greater 

 firmness 1). 



In his posthumous diary Søren Jensen has put down 

 the following observation regarding Peden groeniandicMs : «[ 

 was utterly astonished to see that this little bivalve was capable 

 of swimming when fuUgrown. It opens and shuts the valves, 

 pushes the water back under the shutting, which takes place 

 with a strong action, and thus rushes backwards through 

 the water. The animals lying on the bottom of a glass of 

 water might in this way «yawn» themselves quite up to the 

 surface«. 



Pecten imbrifer Loven. 



1891—92. Off Scoresby-Sound 167 fms. Clay with large stones 1 valve. 



1900. Forsblad-Fjord 50 — Clay with stones 1 valve. 



1900. Fovsblad-Fjord 50—90 — Clay with stones ca. 125 spec. 



The Kolthoff-Expedition of 1900 took 1 specimen SE. 

 of Pendulum-Island (74° 35' N.), where the depth was 79 fms.; 

 the ground consisted of mud and stones (Hägg 1. с. p. 30). 



The specimens at hand belong to the variety major Leche 

 and obtain a length of up to 20*5 mm. 



The sculpture of the left valve is exceedingly variable, it 

 is sometimes provided with numerous radially arranged hollow 

 vesicles, sometimes it only shows faint traces of such. 



