480 ZOOLOGY. 
the adult, terrestrial form, sometimes being about a third of 
a metre (12 inches) in length, the adult being twenty centim- 
etres (8 inches) long, forming an example of what occurs 
in the Amphibians and also certain insects, of the excess in 
size and bulk of the larva over the more condensed adult 
form. This law is also strikingly observed in the Pseudes 
(Fig. 437). This fact of prematuritive, accelerated, vegetative 
development of the larva over the adult is an epitome of what 
has happened in the life of this and other classes of animals. 
The fossil, earliest 
representatives of the 
Amphibians, as we 
shall see farther on, 
At ) were enormous, mon- 
RN strous, larval, prem- 
Wee ature forms com- 
Fig. 435,—Siredon or lurval Salamander.—From pared with their de- 
Tenney’s Zoology. scendants. Thesame 
Jaw holds good in certain groups of Crustacea (trilobites), 
insects, fishes, reptiles and mammals. 
The axolotl or siredon abounds in the lakes of the Rocky 
Mountain plateau from Montana to Mexico, from an altitude 
of 4000 to 8000 or 9000 feet; the Mexican axolotl being of 
a different species, though closely allied to that of Colorado, 
Utah and Wyoming. The Mexicans use the animal as food. 
Late in the summer the siredons at Como Lake, Wyoming, 
where we have observed them, transform in large numbers 
into the adult stage, leaving the water and hiding under 
sticks, etc., on land. Still larger numbers remain in the 
lake, and breed there, as I have received the eggs from Mr. 
William Carlin, of Como. Thousands of the fully-grown 
siredons are washed ashore in the spring when the ice melts. 
They do not appear at the surface of the lake until the last 
of June, and disappear out of sight early in September. 
The eggs are laid in masses, and are 2 millimetres in diameter. 
Mr. F. F. Hubbell has observed in Como Lake, July 23d, 
young siredons four to six centimetres (14-24 inches) in 
length, and September 3d specimens eight centimetres (3 
inches) long. In Utah, Mr. J. L. Barfoot raised in 1875 
