JEFFREYS. — ARCTIC MOLLUSCA. 49' 



by the Academy of Sciences at Stockholm, explored by dredging 

 the seas of Spitzbergen and Iceland ; the greatest depth reached 

 by him was 280 fathoms. In 1861 a second Swedish expedition 

 was made to Spitzbergen, when a species of Cylychna was re- 

 corded by Professor Loven as having been dredged at a depth of 

 over 1,000 fathoms. A third Swedish expedition in the same 

 direction was made in 1868 ; and by the kindness of Professor 

 Loven I was favoured with an opportunity of examining at Stock- 

 holm some of the results. The dredgings and soundings appear 

 to have extended from 5 to 2,600 fathoms ; and, at the last- 

 named depth, in N. lat. 78° a living Crustacean {Cuma), and a 

 valve of a Mollusk (Astarte compressd) were obtained. Again, 

 in 1871, the Swedish frigate " Eugenia," was dispatched on a 

 scientific voyage to Greenland ; when Mr. Josua Lindahl, who 

 had assisted us in the " Porcupine " expedition of the previous year, 

 was the naturalist in charge. The results of this last expedition, 

 as regards the Mollusca, have not yet been published ; but I was 

 informed by Mr. Lindahl, that in Davis's Straits he dredged a 

 species of Peechiolia (or Verticordia), apparently acutecostata ;* 

 and Professor Loven told me that a Marginella (which is a 

 southern form) and a Limopsis were dredged also in Davis's 

 Straits at a depth of 900 fathoms. 



The importance of such investigations cannot be too highly 

 estimated, especially in a geological point of view. The palaeon- 

 tological basis of the glacial epoch consists mainly in the identi- 

 fication of certain species of Mollusca, which inhabit the Polar 

 seas and are fossil in Great Britian and even as far south as Sicily. 

 But such species may owe their present habitat and position to 

 other than climatal causes, viz., to the action of marine currents. 

 Certain small Spitzbergen species (e.g. Legafrigida^ and L. ahys- 

 sicold), have been lately found everywhere in the depths of the 

 North Atlantic as well as in the Mediterranean ; and the question 

 naturally arises what is the home of these species, or where did 

 they originate ? That question cannot be answered for want of 

 sufficient information. It is likewise quite premature to assume 

 that Arctic Mollusca comprise very few species, although they 

 may abound in individuals. We know very little about them, 

 because of the difficulty of investigation. The researches of Pro- 

 fessors Torell and Sars induce us to believe that these Mollusca 

 are not less varied than numerous. 



It is hoped that each of the vessels to be fitted out for the 

 Polar expedition will have a donkey engine, by which the dredges 

 can be lifted ; and that a sufficient supply of necessary apparatus 

 will be provided, regard being of course had to the limited space 

 allowed for such a secondary object. The great experience of 

 Capt. Nares renders any suggestions as to dredging quite super- 

 fluous. 



* This species is fossil in the Coralline Crag of Suffolk, and the Zanclean 

 formation of Sicily ; and I dredged it at considerable depths in the Bay of 

 Biscay. It has been also dredged by Mr. Arthur Adams in the seas of Japan, 

 and by Count Pourtales in the Gulf of Mexico. 



