JORDAN : NEW BRITISH MOLLITSCA. 269 



Moreover, Canon Norman accepts Arctic conditions over a large 

 part of his area, for at the 1,50.0-fm. line off the West of Ireland 

 the bottom temperature is 36° Fahr., which is several degrees colder 

 than the temperature of the sea bottom off the North Cape, and only 

 some six degrees above the lowest temperature in the "Cold area." 

 Surely if Arctic conditions are accepted in one part of the British 

 Marine Zoological area they must also be accepted, when they occur, 

 in any other. 



I submit that it is wiser — more philosophical — to ascertain the 

 physical conditions which prevail, and, whether they vary or are 

 constant, make our theories and principles fall into line with them, 

 than to accept one set and reject another because they do, or do 

 not, accord with preconceived opinions as to what they ought to be. 



EXPLANATION OF PLATE XVI. 



1. Dentalium senigmaticum, n.sp. 5. Eulima Martjii-Jordani, n.sp, 



2. Piincturella Chasteri, n.sp. 6. Eiilima Frielci, n sp. 



3. Trochiis tetragonostoma, n.sp. 7. Actajon Brnwni, n.sp. 



4. Trochns Coulsoni, n.sp. 8. Actaeon exilis, Jefir. 



