DOLPHIN. 



245 



mackerel, with a cartilaginous keel on the sides of the tail, 

 about a foot long. 



The common species is 



FIG. 255. PILOT-FISH. 



The Dolphin-Pish (Corypfiana) must not be confounded with the true dolphin 

 (Delphinus), to be described hereafter. Nevertheless, the Coryphccna are equally sub- 

 jects of universal admiration. 



During a calm these fishes, when swimming about a ship, appear of a brilliant blue 

 or purple, shining with metallic lustre in every change of reflected light. On being 



FlG. 256. CORYPH-rEN'A. 



captured and brought on deck, the variety of these tints is very beautiful : the bright 

 purple and golden yellow hues change to a brilliant silver, varying back again into the 

 original colours, purple and gold. This alternation of tints continues for some time, 

 diminishing in intensity, and at last settles down to a dull leaden hue. 



"Parting day 



Dies like the dolphin, whom each pang imbues 

 With a new colour, as it gasps away, 

 The last still loveliest, till 'tis gone and all is grey." 



The Riband Fishes (Ttenioids)* are distinguished by an extremely 



* Taivia, tsenia, a riband ; elSos, eidos, form, shat>e. 



