780 The American Naturalist. [September, 
As the Hudson and Delaware Rivers are connected by a canal 
which runs from Kingston on the Hudson to Port Jervis on the Dela- 
ware it is not improbable that the Mud Puppy will at some future time 
be found in the Delaware. - At present no record of its occurrence in 
the Delaware is known to me, and probably it has never yet been 
found in that river. At least no mention of the species is made in 
Dr. C. C. Abbot’s Catalogue of the Vertebrates of New Jersey, pub- 
lished in 1868, nor in Julius Nelson’s revision of the same catalogue, 
published in 1890. 
The presence of the species in the Hudson and its tributaries is 
worthy of note, as it is one of the very few instances in which we have 
apparently good evidence that the habitat of an aquatic animal has 
been unintentionally enlarged through human agency. 
Wm. B. Marsnatt, Albany, N. Y. 
The Foot in the Amniota.—It is well-known that the Dorking 
fowl is the only living bird which, in the adult condition, possesses a 
five-toed foot. Messrs. G. B. Howes and J. P. Hill have recently 
studied this form and they conclude’ that the two inner toes are the 
result of fission of the hallux and that the variation in number of 
phalanges in the supernumerary toe is caused by degree of longitudi- 
nal subdivision. The hallux metatarsal is proximally prolonged into 
a rod of bone running parallel with the other metatarsal and articu- 
lating upon the inner condyle of the tibio-tarsus, a reversional char- 
acteristic unknown in other living birds, through which Archzeopteryx 
had already passed and for which we must go back to the last aber- 
rant tetradactyle Dinosaurs. In the general portion of this paper 
they show that this extra toe is not to be interpreted as a reversional 
reappearance of a usually missing hallux but rather as a splitting of 
the hallux normally present. Going farther they point out that the 
phalangeal characters of the different classes of air-breathing verte- 
brates throw light upon the phylogeny. In all mammals’ the phalan- 
geal formula is 2, 3, 3, 3, 3, or less; that of the Sauropsida 2, 3, 4, 5, 4, 
or less by reduction, while that of the Amphibia is 2, 2, 3, 4, 3, or less. 
In no known Amphibian, living or extinct, has the second digit more 
than two phalanges, and hence neither the sauropsidan or the mam- 
malian foot can be derived from that of the Amphibia except by a 
process of intercalation of which we have no other evidence. This in 
Jour. Anat. and Phys., xxvi, 395, 1892. : 
*Except Cetacea, where Kiikenthal argues that the supernumerary phalanges are 
dismembered and duplicated epiphyses. 
