114 GEOGKAPHICAL DISTRIBUTION. 



destitute of such forms, whereas the evidence brought by the 

 "Talisman" tends in just the opposite direction. Thus, in one 

 haul taken off the Cape Verde Islands, in four hundred and fifty 

 metres water, the net brought up no less than one thousand and 

 thirty-one fishes, mostly belonging to the genus Melanocephalus. 42 

 At depths of one thousand to one thousand five hundred metres in 

 the North African Atlantic, they are stated by Milne-Edwards to 

 abound, and on the bank lying some one hundred and twenty miles 

 off Cape Nun, where in water of from two thousand to two thousand 

 and three hundred metres M. Vaillant obtained the singular Eury- 

 pharinx pelecanoides, they are still very varied. Many of the species 

 possess an extraordinary vertical range, accommodating themselves 

 apparently with ease to the most varied conditions of pressure. 

 Alepocephalus rostratus is met with in a zone included between 

 nine hundred and three thousand six hundred and fifty metres, and 

 much the same distribution characterises Scopelus Maderensis. 

 Macrurus affinis is found between five hundred and ninety and two 

 thousand two hundred metres. The greatest depth from which 

 any fish has been obtained is about five thousand metres (Bathyopis 

 ferox). 43 



The deep-sea fishes, although frequently characterised by many 

 very remarkable abnormalities of structure, such as the enormous 

 development of the head or jaw, the ribbon-like body, and the 

 possession of phosphorescent organs, do not belong to any peculiar 

 order, and are in the main simply modified forms of surface types. 

 A large proportion of the species belong to the families Ophidiidae, 

 Scopelidae, and Macruridse. 



In summing up the results obtained from a first general survey 

 of the collections obtained by the " Challenger," Sir Wyville 

 Thomson believes that we are warranted in arriving at the follow- 

 ing general conclusions : 44 



" 1. Animal life is present on the bottom of the ocean at all 

 depths. 



' ' 2. Animal life is not nearly so abundant at extreme, as it is 

 at moderate depths; but, as well-developed members of all the 

 marine invertebrate classes occur at all depths, this appears to de- 

 pend more upon certain causes affecting the composition of the 

 bottom deposits, and of the bottom water involving the supply of 



