26 Osteological Studies of the Subfamily Ardeince. 
The four joints of the middle or third digit have the general 
characters as given for these phalanges above. Measuring them 
in the same way and in the same order, I find that the proximal 
phalanx to be 4 centimetres long ; the next 3.9, the next 2.1 ; 
and the ungual one, measured as before, 1.1 centimetres long. 
Outer digit has five joints agreeing in the main with the other 
phalanges of the toes of this heron’s foot. They measure, in the 
order as given above, from proximal to last one, 2.9, 2.8, 1.9, 1.7 
and 1 centimetre long. Of course the actual length of these un¬ 
gual measurements will be found to be rather more than those 1 
have given, but it must be remembered that I only present the 
length of the chord from the tubercle on the under side of the 
proximal extremity to the apex of the joint. 
Herons possess no special ossifications other than those I 
have mentioned, that I am aware of, in their skeletons. 
They have, in addition to their general structure, three pecu¬ 
liar external characters in common with a no less remote^ related 
group of birds than the Caprimulgi. Coues, in characterizing 
the Night-jars, says: “Besides the semi-palmation of the feet, 
there is another curious analogy to wading birds ; for the young 
are downy at birth, as in Prceeoces , instead of naked, as is the rule 
among AltricesP (Key, 2d Ed., p.448.) This author does not 
mention, in the same connection, the third character, no doubt it 
having slipped his mind at the moment when the above quoted 
paragraph was penned. It is, that both the Caprimulgi and 
the Ardeince possess in common, that very rare character,—the 
true pectination of the inner margin of the claw to the middle toe 
of pes. 
Morphologists seem to be of one opinion as to the posi¬ 
tion held by the Ardeince, with relation to other groups of birds, 
after a consideration of the osteological and other anatomical 
characters they present. 
Parker says in the Pelagomorphce the charadrian type reaches 
its culmination ; yet the most exquisite forms, such as the Egrets 
and smaller Bitterns, and the most gigantic, as the Adjutant, are 
evidently specializations of a type similar to the pluvialine Schi- 
zognathce (Ency. Brit. 9th Ed. Art. Birds). 
The palatal structure of the Schizognathce almost imperceptibly 
merges into the desmognathous type of skull, while, as in Crax 
