CONDITIONS OF LIFE 



243 



less than fifteen thousand square miles of the sea. For many 

 years afterwards not a single fish was caught, and the species 

 was believed to be extinct, but in recent years it has reappeared 

 in its old haunts. The Scabbard-fish (Lepidopus), an oceanic 

 member of the tribe of Trichiuroids or Hair-tails (Fig. 94A), 

 is another species that is remarkably sensitive to cold weather. 

 It is found in all warm seas, and in New Zealand it is known 

 as "Frost-fish," a name which refers to its habit of swimming 

 ashore in thousands on cold nights, apparently in a state of 

 temporary insanity. The related Cutlass-fish (Trichiurus) has 

 been observed in a benumbed condition oflf the coast of Florida 

 while the temperature was still above freezing-point. 



7IZZZZZ2ZZZZZf^^^^^Ci 



Fig. 94- 



A. Frost-fish {Lepidopiis caudatus), X about ^q ) B. Tile-fish {Lopholatilus 



chamaeleonticeps), > about 20 ; c. Pilot-fish {Naucrates ductor), X about rt*5. 



A few fishes solve the problem of severe weather by going 

 into a winter sleep or hibernation, which is gradually induced 

 by the fall in temperature as winter approaches, and is sustained 

 until the mercury once again rises in the spring. They do not 

 seem to fall into a complete unconsciousness like the reptiles 

 or such mammals as the dormouse, but simply cease to feed, 

 seek shelter among weeds or stones, and become more or less 

 torpid. The Carp (Cyprinus), for example, always moves into 

 deeper water, and this species spends the winter in groups, some 

 of which may contain fifty to a hundred individuals. They 

 make a cavity in the ground and pass the time until spring 

 huddled together in circles with their heads together. Respira- 

 tion is so much slowed down that the movements of the gill- 



