Adaptations of Fishes 197 



phausia, it seems to me the assumption is not less certain than 

 the assumption that twelve structures resembling each other in 

 certain particulars have a common function to that proved for 

 one only of the twelve. 



" I am inclined to the belief that whatever regulation of the 

 action of the phosphorescent organ occurs is controlled by the 

 regulation of the supply of free oxygen by the blood-stream 

 flowing through the organ ; but, however this may be, the essen- 

 tial fact remains that the organs in Porichthys are true phos- 

 phorescent organs." (GREENE.) 



Other species of Porichthys with similar photophores occur 

 in Texas, Guiana, Panama, and Chile. The name midshipman 

 alludes to these shining spots, compared to buttons. 



Globefishes. The globefishes (Tetraodon, etc.) and the por- 

 cupine-fishes have the surface defended by spines. These fishes 

 have an additional safeguard through the instinct to swallow 

 air. When one of these fishes is seriously disturbed it rises to 



FIG. 149. Sucking-fish, or Pegador, Leptecheneis naucrates (Linnams). Virginia. 



the surface, gulps air into a capacious sac, and then floats belly 

 upward on the surface. It is thus protected from other fishes, 

 although easily taken by man. The same habit appears in some 

 of the frog-fishes (Antennarius) and in the Swell sharks (Cepha- 

 loscyllium) . 



The writer once hauled out a netful of globefishes (Tetrao- 

 don hispidus} from a Hawaiian lagoon. As they lay on the bank 

 a dog came up and sniffed at them. As his nose touched them 

 they swelled themselves up with air, becoming visibly two or 

 three times as large as before/ It is not often that the lower 

 animals show surprise at natural phenomena, but the attitude 

 of the dog left no question as to his feeling. 



Remoras. The different species of Remora, or shark-suckers, 

 fasten themselves to the surface of sharks or other fishes and 

 are carried about by them often to great distances. These 



