Dr Dalton jun. on the Proteus anguinus. 335 



Six of these species are found in various grottoes of Car- 

 niola, and the seventh in Dalmatia. Two different species 

 never exist together in the same locality, though sometimes 

 the same species is found in more than one grotto. One of 

 the principal marks of distinction is their size, the maximum 

 length of the different species varying from9J- to llf inches. 

 The tint of the skin is in some species more rosy, in others 

 yellowish ; the head is also pear-shaped, triangular, or more 

 globular in form. The eyes also are more distinctly visible 

 in some speciesthan in others, and vary somewhat as to their 

 situation. 



The body of the animal is cylindrical, like that of an eel, with 

 its posterior portion compressed laterally into a kind of verti- 

 cal membranous fin. There are four extremities, the an- 

 terior three-toed, the posterior two-toed. The posterior are 

 considerably smaller and more feeble than the anterior. The 

 first circumstance which strikes the notice of the observer 

 is the almost entire absence of colour, 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. The heart can be distinctly 

 seen through the skin at the anterior part of the neck, beat- 

 ing 48 or 50 times per minute. The dark colour of the liver 

 also shews through the integument very plainly on the under 

 surface of the abdomen. The whole aspect of the animal re- 

 minds one very strongly of the foetal condition of the higher 

 vertebrata, particularly a,bout the extremities, where the 

 transparency of the integument shews to best advantage. 

 Notwithstanding, however, its delicacy and apparent feeble- 

 ness, its motions are occasionally very rapid and energetic. 

 They consist of swift undulating movements of the eel-like 

 body and tail. The 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 extremities 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 prin- 

 cipal stem being divided into six or seven branches, and these 

 again subdivided into fine twigs. When the Proteus is 



