100 
PEALE’S EGRET HERON. 
characteristic mark should fail us, it is still no reason why the 
group is not natural which it has hitherto been believed to 
represent. A minute peculiarity may furnish a most useful though 
artificial generic or specific character, while an apparently impor¬ 
tant and evidently natural one may be of no use for this purpose. 
In our system the family Ardeidx is composed of nine genera, of 
which none is subdivided except Jlrdea itself, which with Ciconia 
are all that are strictly typical. Besides the more direct relations, 
this family is connected with the Pallidas by the curious though 
anomalous Courlan, also allied to the Gruinas by its feet, as well 
as to the Scolopackhe. But to these the genus Eurypyga forms a 
very strongly marked and still better passage. At the same time 
the Platalea, which in its feet shows the transition to Phcenicop - 
teridse, and by its curiously flattened bill stands alone, is so similar 
in internal conformation, and especially the sternal apparatus to 
the genus Ibis that they ought in this respect to go together; 
though Tantalus , one of the Ibidce, is constructed rather upon the 
osseous plan of the Jlrdeidx! Scopus, Jlnastomus, Canchroma, and 
even Dromas to a minor extent, each and all exhibit striking 
anomalies in their bills, so that Jlrdea and Ciconia are the only two 
typical genera with sharp-pointed bills of the whole group. In 
order to comprehend all these forms of bills, it becomes necessary 
to restrict greatly the physical characters of the family, and we 
can merely observe that in the Jlrdeidae the bill, whatever be its 
form, is longer than the head, very robust, and almost always 
sharp, with cutting edges. The neck is long. The feet long, and 
always four-toed, the hind toe strong and well developed: the 
tarsus is longer than the middle toe, and toes and nails both are 
also long. The wings are of moderate length, and obtuse. The 
tail is never long, nor otherwise remarkable, and consists of 
twelve, or only of ten feathers. 
There is no marked external difference between the sexes, but 
