124 ANIMAL LIFE 



some of them striking, some not especially so, are mostly 

 chosen from the vertebrates and from the insects, because 

 these two groups of animals are the groups with which be- 

 ginning students of zoology are likely to be familiar, and 

 the adaptations referred to are therefore most likely to be 

 best appreciated. Quite as good and obvious examples could 

 be selected from any other groups of animals. The student 



FIG. 54. The deep-sea angler (C'oiynolophus reinhardti), which has a dorsal spine 

 modified to be a luminous "fishing rod and lure," attracting lantern-fishes 

 (Echiostoma and ^Ethophora). An extraordinary adaptation for securing food. 

 (The angler is drawn after a figure of LUTKEN'S.) 



will find good practice in trying to discover examples shown 

 by the animals with which he may be familiar. That all 

 or any part of the body structure of any animal can be 

 called with truth an example of adaptation is plain from 

 what we know of how the various organs of the animal 

 body have come to exist. But by giving special attention 

 to such adaptations as are plainly obvious, beginning stu- 



