40 PEOCEEDES^GS OF THE 



Pacific than with the Atlantic ; the separation of the two oceans 

 probably took place late in the Cretaceous period, and was, 

 perhaps, not completed till the Middle Tertiary. At present " the 

 deep-sea fauna of the Caribbean Sea and the Gulf of Mexico 

 is far more closely allied to that of the Pacific than to that of the 

 Atlantic." * 



To enter here further into the results of the cruises of the 

 ' Blake ' would be as unnecessary as to enlarge upon the achieve- 

 ments of the ' Challenger.' The more important portions of the 

 collections have been worked out by specialists ; the number of 

 species previously known from this area were in many branches 

 doubled or trebled, and so complete were the collections, that in 

 the last cruises novel forms were but rarely added to them. The 

 Americans may well be proud of the work of the explorers who 

 have told them where to find living Pleurotomaria, and where to 

 dredge among forests of JBentacrini. 



The Teopical Atlak-tic. 



The ' Challenger' crossed the Tropical Atlantic on the Tropic 

 of Cancer and on the Equator ; the trawlings carried out on the 

 Line being the most productive, although a depth of 2500 fathoms 

 was reached. Altogether at 33 stations deep-sea animals were 

 obtained. On this part of the outward journey jNIurray com- 

 menced his observations and experiments with a towiog-net 

 sunk to a depth of 100 fathoms and more, ascertaining that 

 many nocturnal pelagic animals descend during the day to a 

 depth to which sunlight penetrates only in a diminished degree 

 or not at all. The captures in this area, although not very 

 numerous, included some of the most characteristic and specialized 

 bathybial forms. 



The ' Hassler ' and ' Albatross ' on their passage to the Pacific 

 added seven other stations to those of the ' Challenger.' 



The ' Talisman ' worked thoroughly and successfully near the 

 West Coast of Africa ; about 40 deep-sea stations are recorded 

 on a line between the Canaries and the mouth of the Senegal (see 

 above, p. 28). 



The Southeex Atlajst:ic. 



Por the purposes of this sketch I take Lat. 50° S. as the 

 southern boundary between this and the Antarctic area. 



The work done in this area falls entirely to the share of the 

 ' Challenger.' Eecrossing the Atlantic in the latitude of the 

 Cape of Good Hope, and crossing it for the fourth time in the 

 latitude of the mouth of the Plate Eiver, the Naturalists obtained 

 specimens at 22 stations, some of the deepest hauls (2650 faths.) 

 yielding exceedingly good results, whilst others at no great 



* Three Cruises &c. i. pp. 92, 157. 



