80 
and Structure of the Proteus Anguinus . 
he began, at the same time, to move, one after another, the fore- 
limbs ; so that, making use of the hind limbs as serpents use the 
ventral scales, and employing the fore-limbs to sustain the head 
and chest, the animal proceeded slowly along, crawling in part, 
and in part moving like a biped animal. 
Sometimes, again, the proteus sought to avoid the light by 
making use only of the limbs, keeping then the body and tail in 
a right line, and moving the limbs alternately as quadrupeds do 
when they move by steps. At other times, he moved in a way 
both singular and amusing ; for gliding along so as to graze the 
bottom of the vessel, and supporting himself on the fore-limbs, 
he kept the hind ones applied to the sides of the trunk ; so that 
the body, from the shoulders backward, was entirely suspended 
and gliding ; and from the shoulders forward, was sustained on 
the fore-limbs, which moved alternately, and with much quick- 
ness, along the bottom of the vessel. This mode of progression 
was a mixture of the gliding of fishes and the walking of biped 
animals. A fourth mode in which the animal sought escape 
from the light was by suddenly betaking himself to swimming. 
This always occurred when the whole vessel was at once un- 
covered. At the same time, he glided rapidly over the sides of 
the vessel, and made attempts to escape out of the water, in or- 
der to withdraw himself from the light, which so greatly dis- 
tressed him. Whilst the proteus thus glides along the sides of 
the vessel, his motions resemble those of the lamprey, and, like 
that fish, he drops to the bottom as soon as he ceases to move. 
The lamprey, however, aids his motions by the incurvations of 
the trunk, while the proteus glides along chiefly by the use of 
the tail, which moves to either side with great facility and 
quickness, exactly as occurs to fishes. This difference arises 
from the spine of the lamprey being wholly cartilaginous, and 
theiefore equally flexible in every part ; but in the proteus, the 
spine is entirely osseous, and incapable of any considerable de- 
gree of flexion, except towards the tail. 
Beside the resemblance above noticed in the motions of the 
lamprey and proteus, it is observed that the latter animal, when 
he swims, makes no use of the feet, either to start him in the 
first movement, nor afterwards to sustain his equilibrium. His 
limbs continue applied always to the sides of the trunk, and may 
