124 Dr Rusconi’s Observations m the Natural History 
feet salamander, and under this idea the design was made. The 
next day confirmed these suspicions ; for the leaflets or fringes, 
which formed the extremities of each gill, were already obliter- 
ated, and the stem or shaft was sensibly shortened. The short- 
ening and obliteration of these parts proceeded daily, so that, 
at the end of five days, they were reduced to mere simple buds, 
covered with a skin continued from the head. While these 
changes were proceeding in the gills, the duplicature of skin, 
which covered in part the branchial apertures, became by de- 
grees united to the chest ; the sharp membranous crests, which 
the arches bore externally, were obliterated; the apertures of 
the ears, which gave issue to the water from the mouth, con- 
tracted daily more and more ; the membranous crest of the tail, 
which extended along the back, even to the head, contracted 
also. 
Beside these changes, 'visible exteriorly, the tadpole experien- 
ced others within. The two jaws, especially the lower one, were 
much ossified, and the teeth of this jaw were so hard, as to give 
great resistance to the point of a needle. Were we to arrange 
the different pieces that compose the skeleton of the tadpole, at 
this period, according to their hardness, the lower jaw would 
stand first, afterwards the upper one, then the bones of the cra- 
nium, the vertebrae, and those of the four limbs. At last, the 
germ of the salamander, which had been deposited, on the 28d 
of April, in the form of a little globule, had not, on the 27th 
of J uly, the smallest trace, either of gills or of branchial aper- 
tures. It respired atmospheric air, and made the greatest ef- 
forts to escape from the vessel in which it had been developed. 
In a word, it had assumed the forms which are proper to its 
species in the adult state. 
Having thus exhibited, in detail, the progressive appearances 
which present themselves in the evolution and development of 
the Salamandra platycauda , the author next offers to our view 
a few of the analogous stages through which the other species 
of salamander ( Salamandra exigua J passes. The minute glo- 
bule Fig. 1., represents the egg of its natural size; and the ad- 
joining Fig. a the same egg viewed with the microscope ; the 
line which bounds the globule indicates the viscid substance which 
envelopes it. The eggs of this species are easily distinguished 
