CHAP, iv.] THE CRUISES OF THE 'PORCUPINE: 



Northern Asia, by supposing- a migration throug 



Fro. Z6.Chondrodadiarir(/ot(i, WYVJLIJE THOMSON-. Onrvhnlftlio natural size. (No. :!:>, PI. V.) 



the Arctic Sea. We must know, however, much 



