4G0 THE CANADIAN NATURALIST. [DeC. 



at 2500 fathoms is less than that between salt and fresh water. 



2. That there is a constant interchange between the carbonic 

 acid gas from the bottom and the oxygen at the surface, by which 

 the animals at great depths are provided with means of respiration. 



3. An abundant supply of dilute protoplasm in the water serves 

 as food for the protozoic inhabitants of the deep sea, upon which 

 latter the higher animals subsist. 



4. A glacial suhmarine clinmiQ may exist over any area, without 

 reference to the terrestrial climate of that area. 



5. Cold and warm areas may exist in close juxtaposition, at 

 great depths, and at the same time present quite distinct faunal 

 characters. 



6. The bottom, as analysed by David Forbes, F.R.S., differs 

 essentially in composition from the chalk rock (cretaceous) of 

 England, and no evidence whatever has accumulated to sustain 

 the hypothesis of Dr. Carpenter that the Cretaceous period is at 

 present progressing in the Atlantic sea-bed ; indeed, that gentleman, 

 in a late letter in '' Nature " has practically abandoned this 

 theory. 



7. Temperature is the great agent which determines the 

 distribution of submarine animals ; a view previously maintained 

 by many eminent naturalists and now permanently established by 

 these, and other dredgings in the Atlantic, and by the researches 

 of American naturalists in the North Pacific. 



It is to be regretted that the views of Mr. Jefi'reys in regard to 

 the specific and generic limits of animals, di0"er so widely from 

 those of the majority of modern naturalists. In the present report 

 he unites animals belonging to difi'erent genera under the same 

 specific name ; e. g., Waldlieimia septlgera and TerebrateUa 

 scptata, and those who have had occasion to critically examine his 

 British Conchology, find in it many similar cases. Such deter- 

 minations, of course, will tend to invalidate any conclusions which 

 may be drawn from his report, and will undoubtedly throw a 

 certain amount of confusion upon the whole subject. — W. H. Dall, 

 in The American Naturalist. 



On Astronomy and Geology. — The following is an abstract 

 of a Somerville lecture, bearing the above title, delivered by Dr. 

 T. Sterry Hunt, F. R. S., in the Hall of the Natural History 

 on the 2nd of February, 1871 : — The lecturer explained the 

 reason for coupling together celestial and terrestrial science by 



