276 DAVISON. [Vol. XI. 



fortunate as to have sent me, by a North Carolina dealer in 

 embryological supplies, several very young specimens varying 

 in size from seventy-eight to ninety millimetres in length. 



In this paper it is my intention to give a detailed account of 

 the anatomy of these very young specimens, and by compari- 

 sons with the adult structures as well as with other Amphibians 

 to deduce a few new points in phylogeny. Since there has 

 never been published any complete and reliable account of the 

 anatomy of the adult, it will be necessary for me to begin at 

 this point. 



External Features of the Adult. 



The general form is serpentine, having the same proportions 

 as the body of a teleost eel. The circumference of the largest 

 specimen I have seen was 1 50 mm., and its length almost one 

 metre. The tail occupies about one fourth the length of the 

 animal, and is laterally compressed in such a manner that the 

 area of a cross-section is triangular with the apex at the dorsum. 

 The body is slightly contracted just anterior to the fore limbs 

 forming the so-called neck. The head is twice as long as it 

 is broad, and vertically compressed. The snout is obtusely 

 rounded, but is more pointed than in other urodeles, and ex- 

 tends from six to eight millimetres beyond the lower jaw. 

 The lips of the upper jaw overhang for the most part those of 

 the lower, thus preventing the mud from entering its mouth 

 during its subterranean excursions. The eyes are one and a 

 half millimetres in diameter, have no lids, utilize the epidermis 

 as a cornea, and are situated along a transverse line cutting off 

 the anterior third of the head. The anterior limbs are from 

 fifteen to twenty millimetres in length, and support two or 

 three diminutive digits. The posterior limbs, situated just 

 anterior to the vent, are from fifteen to twenty-five millimetres 

 long, and also have two or three digits. Cope (4) says that 

 specimens have been found having two digits on the anterior 

 limb and three on the posterior. 



A few millimetres anterior to the fore limb is the branchial 

 fissure, securely guarded by two membranous flaps. The skin 

 is smooth, silky, and of a dark brown color dorsally, and of a 



