GIBSON— CBPHALOCIIORDA : " AMPHIOXIDES." 



215 



It is evident from this table that Ampliioxides is equally capable of a littoral and 

 of a pelagic existence. In order to gather some idea of the depth at which it lives 

 pelagically, the specimens taken in water deeper than 300 fathoms (^. e. those from all 

 stations except the ones marked with an asterisk) are in the next table considered 

 separately. Ampliioxldes was obtained from 7 deep-water localities, out of 15 from 

 which plankton was taken, showing that it is of very general occurrence in the open 

 sea in the regions in question. 



(The following, taken with a Fowler net, are not included : — 

 1 A. 2>elagicus (8-1 mm.), between 250 and 500 f. 



1 A. pdaguus (8-1 mm.), | ^^^^^^^ ^ ^^^ ^50 f.) 



2 A. vald'iviai (O'l and 10-6 mm.), J 



A fairly wide range of depth is indicated. No specimens were obtained at depths 

 greater than GOO fathoms. Only 7 plankton samples were taken from such depths, so 

 that it is not proved that Amphioxides does not occur so far down. Nevertheless, it 

 seems hardly probable that it can be equally capable of living at the surface and at the 

 great depths (1200-3500 metres) which Goldschmidt suspected it to inhabit. The 

 figures are insuflicient to show whether there is any correlation between size and depth 

 of habitat, and the occurrence of the smallest specimen — 3-9 mm. long — at a depth of 

 500 fathoms may be only a coincidence. 



29* 



