200 DR. H. GADOW ON MEXICAN [June 6, 
interesting that these burrowing, slowly moving worm-like 
creatures have managed to travel over at least 1500 miles of 
ground, covered with humus, since the close of the Miocene epoch, 
i.e. since the separation of the Antilles (cf p. 237). A not 
unreasonable computation of one million years carries us back into 
the Miocene epoch. The rate of spreading could in this case 
have been extremely slow, only about one mile in 700 years, and 
this works out at three yards a year. Of course this is mere 
speculation, but it may be as well to give even such an imaginary 
instance of slow spreading. The fact remains that Dermophis ~ 
has done it, and whether we double or treble the rate of progress, 
or increase the time two- or three-fold, the result remains within 
very reasonable possibility. 
URODELA. 
The Amblystomatine are a pre-eminently Eastern Palearctic 
group; only two out of eight genera occur in North America: 
Dicaumptodon ensatus in California, and Amblystoma, with some 16 
species, on the North-American Continent, and one, A. persimile 
in Siam. In Mexico only two species occur. 
Amblystoma tigrinuwm, the larval form of which, when per- 
manent, is the famous Axolotl. This species has an enormous 
range, from the State of New York to Dakota and Colorado, whence, 
apparently now with wide gaps between, it extends through 
Mexico, as far south as the valley of Mexico City. But its dis- 
tribution in Mexico is, at least now, restricted to the western 
Sierra Madre and the southern part of the Mexican plateau. 
Well-ascertained localities of this species are the following :— 
West of Chihuahua Town; West of the town of Durango; 
Cumbre de los Arrastrados in Jalisco; somewhere N.W. of Guada- 
lajara ; district of Autlan in Jalisco ; Lake Patzcuaro in Michoacan, 
Valley of Mexico, notably Lakes Xochimileo and Zumpango 
(but not Lake Texcoco, to which alone Weismann’s dismal dream 
to account for the permanent Axolotl stage could apply!). 
Possibly there are Amblystoma, either metamorphosing or as 
Axolotls, in or near some of the other lakes of Michoacan and 
Jalisco, but they have as yet not been recorded from Lake Chapala ; 
and I found none in the Lakes of Zapotlan; nor were such 
creatures, or even the name Axolotl, known to the natives. 
A. altamirani.—This species, which metamorphoses regularly into 
a gill-less Newt, is known only from the streams of the mountains 
which border the western and south-western side of the Valley of 
Mexico. It was discovered in the Montes de las Cruzes, about 15 
miles to the west of Mexico City, at an altitude of 8800 feet. In 
1902 I found it also above Contreras, in the Sierra de Ajusco, 
some 12 miles south-southwest of the city, at an altitude from 
8500 feet upwards to 8800 feet. Further up the rivulets are 
apparently too small. I stated in ‘ Nature,’ Feb. 5, 1903, that 
searching in the streams only a little above the City of Mexico, 
