PREFACE. 
_ The Arabs have a proverb which declares, “ That 
men are four ;— first, he that knows not andknows not that 
he knows not; he is a fool, shun him; second, he that 
knows not and knows that he knows not; he would learn, 
teach him; third, he who knows and knows not that he 
knows; he is asleep,awake him; fourth, he who knows and 
knows that he knows; he is wise, follow him.” 
According to this proverb, the truth of which none 
can gainsay, the acme of wisdcm lies not onlyin having 
knowledge, but in being absolutely certain of that knowl- 
edge, which certainly can only be acquired by actual per- 
sonal investigation of a given subject. 
It is the object of this little book to show teachers 
and others interested in the subject of which it treats, how 
to see for themselves, by showing them what to look for, 
and I shall try and not ask my readers to lookforanything 
which I have not myself seen. 
There are many books written upon Zoology, but 
few, however, are by original observers. It has long been a 
(3) 
