a 
NATATORIAL FAMILIES. — ANALOGIES. 189 
first — are very full, and comprise both genera and sub- 
genera. 
-(209.) The Anatine, or river ducks, show the typical 
perfection of the whole family, in possessing that strong 
instinct for domestication so eminently characteristic of 
the rasorial type. They are very good swimmers, but 
not expert divers ; this latter faculty being possessed in 
177 a much greater degree by 
#, the marine ducks of the 
next division, where the 
ae i 6 «= hind toe (fig. 177. a) is 
— much broader than in the 
fluviatile species (6): this difference, in fact, forms 
the typical distinction of the two divisions; and how- 
ever inexplicable the fact may appear to us, it is 
nevertheless certain, that all ducks with a very broad 
hind toe are the most perfect divers. In the typical 
genus Anas, at the head of which stands the shoveller 
duck (A. elypeata Lin.) ; the lamelle of the bill project 
in different degrees beyond the margin. These, after 
describing their own circle of subgenera, are followed 
by the sheldrakes and Muscovy ducks. The beautiful 
genus Dendronessa Sw., composed of the summer ducks, 
next succeeds, as the rasorial genus; then follow the 
widgeons (Macera); and the fissirostral type of Anserelia, 
or the little geese ducks of India, conduct us back to 
the subgenus Boschas among the typical ducks. This, 
in our estimation, is the true circle of the Anatine. 
(210.) The Fuliguline, or marine ducks, in their 
natural disposition have none of the domestic habits of 
the last. They live out at sea, and, like all raptorial 
types are naturally very shy and wild; while their dis- 
tinguishing character, as manifested in the structure of 
the hind toe, has already been explained. The genera are 
composed of —1. Somateria, or the eiders, in which is 
the beautiful king duck (fig. 178.) ; 2. Oidemia, or the 
scoters; 3. Fuligula, or the pochards; 4. Clangula, or 
the golden eyes; and, 5. Heralda, or the long-tails. 
The analogical resemblances which these groups bear to 
the five genera of the freshwater ducks are very striking, 
