SKIMMERS. 263 



in the liquid element ; these are never seen on land but dur- 

 ing the short period of reproduction ; many indeed leave 

 their eggs for the greater part of the time to the hatching 

 influence of the sun. Some, as many of the Anatid.e, dwell 

 mostly on fresh waters, and retire into the interior to breed ; ' 

 approaching the sea only in the period of their migrations. 

 All the birds of the order nest on the ground, in holes, 

 crevices or shelvings of rocks, or merely upon the elevated 

 borders of the strand ; a few, however, habitually or acci- 

 dentally nest in trees or in hollow stumps. As the young 

 are early capable of providing shelter for themselves, many 

 have no proper nest, and in all it is rude and artless. Their 

 food, as their habits indicate, is chiefly aquatic ; such as 

 fish, fry, shelly mollusca, and marine insects, to which some 

 species also add vegetables. 



SKIMMERS. (Rhincops. Lin.) 



In the singular birds of this genus the bill is longer than the 

 head, straight, much compressed, but somewhat four-sided at the 

 base ; upper mandible much shorter than the loAver, somewhat curv- 

 ed, rather acute, grooved so as to receive the edge of the lower: 

 lower mandible narrower, truncated or cut oiF at the point, fitting 

 into the channel of the upper like the blade of a knife. Nostrils ba- 

 sal, marginal, concave, longitudinal, open and pervious. Tongue very 

 Bhort, narrow and acute. Feet, moderate, slender; tarsus some- 

 what longer than the middle toe ; middle toe longest ; inner shorter 

 than the outer : webs emarginate : the lateral toe bordered exteriorly 

 with a narrow membrane : hind toe short, articulated rather high on 

 the tarsus, touching the ground at tip. Wings extremely long, curv- 

 ing upwards ; 1st primary longest, and with the 2d much longer than 

 the rest. Tail forked, of 12 feathers. 



The sexes alike in plumage ; but the young differing from the 

 adult. The moult takes place twice in the year, without inducing 

 much change in the appearance of the plumage. 



