J. C. Dalton, Jr., on the Proteus anguinus. 389 
viz.: the H. Laurentii. Specimens of two other species, the 
H. Haidingeri and H. Freyeri were obtained afterwards at the 
Vienna Museum for purposes of dissection. 
toed 
smaller and more feeble than the anterior. The first cireum~ 
stance which strikes the notice of the observer is the almost en- 
tire absence of color, and the transparency of the tissues, which 
allow the cutaneous and subcutaneous vessels, and even the veins 
and arteries of the extremities to be perceived without difficulty. 
he heart can be distinctly seen through the skin, at the anterior 
part of the neck, beating 48 to 50 times per minute. The 
dark color of the liver, also, shows through the integument 
very plainly on the under surface of the abdomen. ‘The whole 
aspect of the animal reminds one very strongly of the foetal con- 
dition of the higher vertebrata, particularly about the extremities, 
Where the transparency of the integuments shows to best advan- 
‘lage. Notwithstanding, however, its delicacy and apparent fee- 
bleness, its motions are occasionally very rapid and energetic. 
They consist of swift undulating movements of the eel-like body 
‘tail. ‘Ihe limbs are nearly useless during rapid progression, 
and remain almost motionless, applied to the sides of the body. 
It is only in the slow motions of crawling and turning, that the 
®xtremities are used, and then only in a feeble and imperfect — 
manner. The gills, three in number on each side of the neck, 
are in the form of long tufts; each principal stem being divided 
into six or seven branches, and these again subdivided into fine 
Wigs. When the Proteus is in rapid motion, they become dis- 
tended With blood, and of a bright scarlet color, contrasting finely 
With the light yellowish, indefinite hue of the rest of the body. 
a state of rest, however, they are often perfectly pale, like 
any other part of the surface. The animal occasionally lifts its 
he mouth or nostrils, 
the Proteus can live many hours; carrying on its respiration by 
the langs and through the skin only; but in a warm apartment 
Particularly if the skin is wiped dry, as I have myself ascertained 
by tryi the : t: I 
Se cin tadict pany of the head nearly to the end of the tail, 
