“Tree-Ducks” of the genus Dendrocygna. 57 
directed backward. An accessory or first metatarsal is comparatively 
large and attached by ligament in the usual manner. 
First joint of hallux is long, having a length of 17 mm, and 
the claw to this toe is likewise of good size, though somewhat 
smaller than any of the claws on the anterior toes. 
Although presenting nothing worthy of especial note in their 
morphology, it is to be noted that the joints of the three anterior 
phalanges of pes are all straight, stout, and long bones. 
In my Osteology of Birds (p. 330, eited above), I give the 
measurements for all the joints of the four toes in Branta canadensis; 
some for Olor, and others for certain Anatinae; and, as these 
pedal joints do not differ much in character, it will not be neccessary 
to make a record of much more upon this subject. 
In ordinary Anatinae, the skeleton of the feet is generally 
far more delicately constructed than it is in Dendrocygna. This is 
very noticeable in such species as Polysticta stelleri, Aiz sponsa, and 
others; while in such a fuliguline duck as Charitonetta albeola, the 
basal joint of hallux is of extreme slenderness, and those of the 
other toes are of markediy small calibers with respect to the size 
of their shafts. 
The proportionate lengths of the basal joints of the three an- 
terior toes vary among the Anseres, as we would naturally expect. 
For examples of this I submit the following data in the subjoined 
Table. 
Lengths ofthe basal joints of pedal digitsin certain 
Anseres in millimeters. 
Outer toe Middle toe Inner toe 
Dendrocygna autumnalis 23,5 30,5 28,0 
Olor buceinator 42,5 51,0 48,0 
Branta_ canadensis 32,0 40,0 40,0 
Aix sponsa 15,0 19,0 19,0 
Polysticta stelleri 18,0 23,0 23,0 
Hymenolaemus malacorhynchus 20,0 25,0 24,0 
Charitonetta albeola 15,0 20,0 20,5 
Judging from these measurements, it would appear that, every- 
thing else being equal Dendrocygna autumnalis comes nearer to 
Olor buceinator in the proportional lengths of the basal joints of the 
anterior phalanges of pes, than it does to any of the ducks wherein 
