USE AND DISUSE OF ORGANS, 185 
of the organs of flight. With this was combined, as 
these beetles show, no degradation of organization, but, 
on the contrary, a higher and extremely advantageous 
development of other organs, the manducatory and 
locomotive apparatus. A general reduction of the 
power of flight has been shown in the beetle fauna of 
many islands. Thus in Madeira, of 550 specics, over 
200 fly imperfectly or not at all, and for this there is 
no explanation but natural selection. Here the less 
good and enterprising flyers had the advantage, while 
the others were blown into the sea and eliminated. 
The non-application of a previously attained special 
perfection is advantageous in the “struggle for 
existence,” 
In several families of lizards, some genera are ser- 
pentine, as they are termed, which, with elongated 
bodies, possess either fore-legs only (Chirotes), or 
merely rudimentary hind-legs (Pseudopus), or no ves- 
tiges of legs (Anguis). They bear the same relation 
to the great class of normally four-legged lizards as 
the non-flying insects to their own class. They have 
not been arrested in their development, nor are they 
animals in process of evolving four legs; but, as 
Firbringer has demonstrated from the history of 
development and comparative anatomy, their limbs, 
and—if these are entirely absent—the remains of the 
pectoral and pelvic arches and the sternum bear 
indubitable marks of the abortion of a once com- 
plete apparatus. Further comparison shows that this 
atrophy reaches its climax in the snakes, but that it 
is compensated for by the ribs and intercostal muscles 
having undertaken the work of the limbs. Here, 
