336 Dr Dalton jun. on the Proteus angainus. 



in rapid motion they become distended with blood, and of a 

 bright scarlet colour, contrasting finely with the light yel- 

 lowish indefinite hue of the rest of the body. In a state of 

 rest, however, they are often perfectly pale, like any other 

 part of the surface. The animal occasionally lifts its head 

 above water, and takes in air by the mouth or nostrils, which 

 after remaining some time in the lungs, is expelled through 

 the bronchial fissures in the sides of the neck. Notwith- 

 standing this frequent respiration of air, however, and the 

 large size of the lungs, the pulmonary respiration is a very 

 imperfect one, and altogether secondary to the bronchial. It 

 is said that in a moist and cool place, as, e.g., on the floor of 

 the Magdalena Grotto, the Proteus can live many hours, 

 carrying on its respiration by the lungs, and through the skin 

 only ; but in a warm apartment, it expires in a few minutes 

 after being taken out of the water, particularly if the skin is 

 wiped dry, as I have myself ascertained by trying the expe- 

 riment. Over the whole surface of the skin, from the anterior 

 part of the head nearly to the end of the tail, there are mi- 

 nute punctiform openings, the orifices of cutaneous follicles, 

 which exude an abundance of transparent colourless mucus. 

 The peritoneal cavity is also filled with a similar exudation. 

 There are but few peculiarities about the skeleton. The 

 bodies of the vertebrae are articulated to each other by con- 

 cave surfaces as in the fishes, instead of one of the articulat- 

 ing surfaces being concave and the other convex, as is the ge- 

 neral rule among reptiles. The anterior extremities consist of 

 a cartilaginous clavicle and scapula, fused into a single piece, 

 a humerus, radius and ulna, three carpal pieces, and three 

 digits, the two inner ones of which have three phalanges each, 

 and the outer one, which is shorter, only two. The posterior 

 extremities are supported by a simple pelvic ring, resting 

 against the sides of the vertebral column. They are com- 

 posed of a femur, tibia and fibula, a tarsus composed of three 

 pieces, precisely similar to those of the carpus, and two digits 

 of three phalanges each. All those parts are entirely carti- 

 laginous, or so slightly ossified that it is difficult to be sure 

 whether there is any true bony formation or not. The snout 

 is rather broad and thick. The nostrils open on the under 



