Adaptations of Fishes 69 
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. 
“Tam 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 
Fie. 51.—Sucking-fish, or Pegador, Leptecheneis naucrates (Linneus). 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 
