406 
5—40 fms., off the East-Canada (Witheaves 1869). 
33—122 fms., off the coasts of New-England (Verrill 1882). 
Jeffreys has not produced any detailed proof for his hypo- 
thesis, but he seems to be right in his supposition — at least as 
far as Pecten islandicus is concerned — that the dead shells here 
can be found at greater depths than those at which the animals 
presumably have lived. 
G. 0. Sars”s hypothesis on a sinking of the sea-bed 
off Romsdalen i Norway. 
In ,,Forhandlinger i Videnskabs Selskabet i Christiania, 1872" 
G. 0. Sars forms a hypothesis on a former sinking of the sea-bed 
off Romsdalen in Norway. This he partly bases on the fact that 
dead shells of some shallow-water molluses: Mya truncata var. udde- 
" vallensis, Saxicava rugosa, aud Venus casina, were dredged at depths 
of about 50 fms. These molluscs are all, according to Sars,… ,,un- 
doubtedly littoral animals which, as a rule, live near the low-water 
mark". It must, however, be observed that, according to more 
recent investigations about the bathymetrical range of these animals, 
they all live at depths reaching to ca. 50 fathoms or more. For 
these species the following distribution is recorded: 
Mya truncata: 
0—40 fathoms (Jeffreys 1870). 
0—50 fms. (G. 0. Sars 1378). 
Saæicava rugosa L. (incl. $. arctica L.): 
0—300 fathoms (G. 0. Sars 1878). 
0—250 fms. Drontheim Fjord. (Norman 1893.) 
Venus casina: 
10—40 fms. (G. O. Sars 1878). 
20—60 fms. (James Å. Grieg 1896 & 1897). 
It will be seen that, as far as the hypothesis is based on the 
occurrence of shallow-water molluses at greater depths than those 
