164 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



the two former of which I had the honour of 

 accompanying ; and as the result of my investigations 

 has been to add considerably to the list published 

 by Dr. Brady, I have received Dr. Murray's per- 

 mission to bring this communication before the 

 Society. 



On examination of the various deposits obtained, 

 special care has been observed in selecting twelve 

 samples from the cold area and twelve from the 

 warm area. All these have been carefully examined 

 microscopically, with one object in view — namely, to 

 determine approximately the distribution of the 

 Rhizopod fauna of these two areas, which are 

 doubtless the richest Rhizopod ground outside the 

 tropics, and have a great inequality of temperature. 



The study of the organisms found in these areas 

 -will therefore be of considerable interest, and no 

 less importance, in throwing some light upon the 

 now general question of the geographical distribution 

 of this interesting group of organisms, due to the 

 great differences of temperature. 



The region known as the Faroe Channel is that 

 portion of the Atlantic Ocean to the north of the 

 mainland of Scotland, which is bounded on the 

 north-west by the Faroe Islands, and on the south- 

 east and south by the Shetland and Orkney Islands, 

 the shores of Caithness and Sutherland, and 

 Hebrides. 



It was shown by the results of H.M.SS. Knight 

 Errant and Triton expeditions that a submarine 

 ridge exists right across this channel, separating the 

 cold water of the Arctic Seas and the warm water 

 of the Atlantic, the greatest depth on the crest of 

 which is 380 fathoms. The average depth over this 

 ridge, which has been named after the late Sir 

 Wyville Thomson, is from 250 to 280 fathoms; in 

 one part, however, there is a gap with a depth of 

 380 fathoms, as mentioned above. It is 100 miles in 

 length by 10 miles wide. On each side of the ridge 

 the depth increases to GOO fathoms or more. 



