224 FOOT-NOTES TO EVOLUTION. 
in common that the coral reefs, rocky islands, and tide 
pools of the tropics have not? 
Mf mh 
a 
Fic. 16.—Skeleton of the spotted greenling (Hexagrammos decagram- 
mus). From nature, by W. S. Atkinson. A northern fish, with 
vertebrz numerous and small, 
CK 
CK « ‘ 
QS epee 
In this connection we are to remember that the fewer 
vertebre indicates generally the higher rank. When 
vertebre are few in number, as a rule 
each one is larger. Its structure is more 
complicated, its appendages are larger 
and more useful, and the fins with which 
it is connected are better developed. In other words, 
the tropical fish is more intensely and compactly a fish, 
Fewer vertebrz 
indicates greater 
specialization. 
Md cS LL, Lf 
« 
(SN Ka 
Fic. 17.—Skeleton of the scarlet rock-fish (Sebastodes miniatus). From 
nature, hy W. S. Atkinson. A species of temperate waters ; the 
vertebree in moderate number. 
“Y 
=— 
with a better fish equipment, and in all ways better fitted 
for the business of a fish, especially for that of a fish that 
stays at home. 
