247 
CRESTED TERN. 
Sterna cristata, Swains. 
PLATE XXX. 
Large ; bill orange ; head and nape black and subcrested ; 
wings and tail of equal length, the latter entirely white ; 
feet black ; tarsus one inch long. 
The Terns, or Sea Swallows, altliougli distributed 
over all temperate and tropical shores, are much 
more restricted in the geographic range of the 
species than has been generally supposed. The 
great similarity of their plumage, and the little at- 
tention which the foreign species have as yet re- 
ceived from modern writers, renders it impossible to 
determine which have, and which have not, been 
described. We shall consequently regard the four 
here enumerated as new: for they "will not agree, 
in all points, with any of those enumerated in the 
works we have consulted. It has been well ob- 
served, that a bad description is worse than useless, 
inasmuch as it not only prevents the clear deter- 
mination of the species intended by others, but em- 
barrasses all succeeding investigations with doubts 
and difficulties. Those we shall here notice may 
possibly have been described long ago ; but if so, 
