SEA-SWALLOW? 
397 
Sea-Swallow’s, which in other respects it closely resembles : 
the lower mandible is the shortest, and the other shuts upon 
it like the two blades of a pair of scissors. 
Terns, or Sea- Swallows, have very long and very pointed 
wings, with forked tails and short feet, in which they 
resemble Swallows ; hut their mode of flight is very different, 
not having that darting rapid course, hut a sort of graceful 
gliding motion, — sometimes high in the air, then falling as 
if they had lost their balance. Though perfectly weh-footed, 
they never swim, hut take their food, consisting of small 
fishes or insects, by descending to the water, and gently 
touching the surface with their beaks. 
We have four species in this country, either residents, or 
occasional visitors. Those which breed here, generally lay 
three or four eggs, without any nest, preferring a low 
shingly shore, on which, we believe, the bird sits in the 
usual manner; hut as it has been ascertained that an 
American species deposits her eggs in a similar situation, 
and leaves them to he hatched principally by the heat of the 
