154 SATURDAY LECTURES. 



This was discussed by Milne-Edwards, the distinguished 

 French naturalist. Meanwhile the energetic Scandinavian 

 naturalists were pushing their researches into the deeper 

 water along the Norwegian coast. 



Still these facts failed to secure that general consideration 

 which was necessary, in order that they should have their 

 appropriate effect on scientific opinion. Individual natu- 

 ralists, it is true, were more or less impressed; the views of 

 Forbes were occasionally called in question, but it was re- 

 served for American naturalists and hydrographers to initi- 

 ate that series of researches which has revolutionized scien- 

 tific opinion, remodelled our views of the physical conditions 

 of the deep sea, and culminated in the most remarkable and 

 fruitful scientific expeditions of any age. 



In May, 1867, under instructions from the Superintendent 

 of the Coast Survey, Assistants Henry Mitchell and L. F. 

 de Pourtales explored the narrow part of the Gulf stream 

 between the northwest end of Cuba and the American coast. 

 Dredgings were undertaken in depths extending nearly to 

 five hundred fathoms, and representatives of all branches 

 of the animal kingdom below the fishes were brought up. 

 The work was interrupted by an outbreak of yellow-fever 

 on board, but the main facts were sufficiently verified, and 

 their important bearings fully set forth in the report of 

 Pourtales. The depths from which these animals were ob- 

 tained were not greater than those from which Sars had 

 obtained living organisms on the Norwegian coast, but those 

 collected by Sars were mostly animals common to the adja- 

 cent shore, or which might be expected to be found in shal- 

 low water by fuller search. But the Gulf-stream dredgings 

 revealed an entirely new and beautiful series of forms, many 

 of them like nothing which had previously been known to 

 naturalists — corals, sponges, crinoids, starfish, echini, shells, 

 worms, crustaceans — all offered new and elegant representa- 

 tives which attracted the attention of specialists in every 

 branch of marine zoology. In the following year six lines 

 of dredgings were run b}^ the Coast Survey observers across 

 the Gulf stream, from the Florida reefs to the deep sea be- 



