and Structure of the Aquatic Salamander. 1 25 
from those of the other, not only by their smaller size, but by 
a circular band of a deep brown, which does not divide the lit- 
tle globule into two hemispheres, but extends a little more on 
one side than the other. On whatever side the envelope is 
turned, the little globule always presents uppermost that hemi- 
sphere which is occupied by the circular band. When the evo- 
lution of the germ commences, this band opens on one side, and 
represents then a line greatly curved, which displays itself by 
degrees, in proportion as the embryo is developed ; one of the 
extremities of this band becomes the head, and the other the 
taiL In a word, it is the brown part of the globule which forms 
the upper part of the future tadpole, and the part which is white 
the belly of the animal ; so that even in the germ, the back is 
less heavy than the belly. 
In Fig. % a , The embryo is represented of its natural size^ 
just after its escape from its envelope, as seen in profile. It is 
suspended by means of one of its hooks to a leaf of Persicaria . 
The letter b of the same figure, represents the same embryo 
seen by the microscope. The two bands of deep brown which 
it exhibits, were those, which, being reunited to two others of 
the opposite side, formed the circular band of the little globule. 
Fig. 3, the same tadpole, seen in profile, of its natural size, 
near the period of its metamorphosis. The author has not 
deemed it necessary to give the intermediate stages of develop- 
ment, as they presented nothing peculiar. The development 
of this species is less subject to accident than the former. In 
all his observations, not one of this species died during the evo- 
lution of the germ. The development of the tadpoles of both 
species, he adds, is accomplished in our climate in the space of 
about three months. 
Having thus exhibited the appearances in the evolution of 
these animals, many questions, says the author, will probably 
occur to the mind of the reader. How is the little embryo 
nourished during its abode in its envelope ? Is it by the glairy 
matter that surrounds it ? How, again, is it nourished after its 
escape from this envelope ? Has it an umbilical cord in the 
first moments of its evolution ? Or rather, is the egg of the sa- 
lamander the animal itself, under a r orm a little different from 
that which it assumes after fecundation ? As to the last ques- 
