120 FAMILY CHARACTERISTICS. 
variety of details in the finish of special parts of 
the structure, such as the number of toes, the pe- 
culiarities of the bill, etc., it is impossible to over- 
look the peculiar form characteristic of each. No 
one who is familiar with the outline of the Par- 
rot will fail to recognize any member of that 
Family by a general form which is equally com- 
mon to the diminutive Nonpareil, the gorgeous 
Ara, and the high-crested Cockatoo. Neither 
will any one, who has ever observed the small 
head, the straight bill, the flat back, and stiff tail 
.of the Woodpecker, hesitate to identify the fam- 
ily formin any’of the numerous Genera into 
which this group is now divided. The family char- 
acters are even more invariable than the generic 
ones; for there are Woodpeckers which, instead 
of the four toes, two turning forward and two 
backward, which form an essential generic char- 
acter, have three toes only, while the family form 
is always maintained, whatever variations there 
may be in the characters of the more limited 
groups it includes. 
The Turtles and Terrapins form another good 
illustration of family characters. They consti- 
tute together a natural Order, but are distin- 
guished from each other as two Families very 
distinct in general form and outline. Among 
Fishes I may mention the Family of Pickerels, 
with their flat, long snout, and slender, almost 
