124 ANIMAL LIFE 
some oi 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 zodlogy 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 
Fic. 54.—The deep-sea angler (Corynolophus reinhardti), which has a dorsal spine 
modified to be «a Iuminous “fishing rod and lure,” attracting lantern-fishes 
(Echiostoma and Afthophora). 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- 
