and Structure of the Aquatic Salamander. 127 
an umbilical cord, nor any thing that could lead him to suspect 
its existence. Having a desire to seize the moment in which the 
viscera of the abdomen begin to appear, he opened an embryo 
longitudinally, just at the period of hatching; but the eye, 
though aided by a glass, could not discover in it the slightest 
trace of organization : the whole appeared to consist of an uni- 
form jelly. He repeated this experiment on another embryo 
which he cut transversely, after having placed it for fifteen mi- 
nutes in alcohol ; but with the exception of the vertebrae, he 
could not perceive, even with the microscope, any trace of orga- 
nization. Continuing this research on other embryos which 
were hatched, he satisfied himself that the organs of digestion 
begin to form two or three days after the embryo has escaped 
from its envelope ; and that they do not attain to that degree of 
development, necessary to the exercise of their functions, until 
about the tenth day. He has seen these organs to be developed 
at the same time that the mouth is formed, and the two hooks 
are obliterated. At this period, however, they are far from ha- 
ving reached their complete development, as the reader may see 
by examining the design annexed to the Fig. c , 18th May, 
which represents a young salamander, in which the belly has 
been opened twelve days after its escape from its envelope, as 
seen by the microscope. In examining this design, he will see 
that the intestinal canal extends, almost in a straight line, from 
one end of the abdomen to the other ; while, in adult salamanders, 
and even tadpoles, when near the period of transformation, this 
canal forms three or four great foldings. He will see, also, that 
the liver and lungs are proportionally very small. In anatomis- 
ing this young animal, the author could perceive no traces of 
the corps franges, nor of the kidneys, nor of the urinary blad- 
der. He remarked, however, that the vertebrae and the lower 
jaw were the only parts of the skeleton which, at this period, 
had acquired a cartilaginous consistence. 
In a future communication, I shall exhibit a fuller account of 
the anatomy of this animal in its tadpole state, and of the phe- 
nomena which accompany its transformation into the perfect sa- 
lamander — drawn partly from the present memoir, but more es- 
pecially from one published by the same author in 1817. 
B. E. 
