230 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



PSEUDOBRANCHUS Gray. 



Auu. Philos., 1825, p. 21G; Cut. Batr. Grad. Brit. Mus., 69 ; Bonlenger, 

 Cat. Batr. Brit. Mus., ed. ii, 1882, p. 87. 



Digits three. Jaws with lioruy sbeatli, Tougue free ia front; eyes 

 distinct. External brauchite three. Parasphenoicl teeth in two rows, 

 united in front, forming a longitudinal j\. One branchial fissure on 

 each side. 



The reduced number of digits and of branchial fissures are the char- 

 acters which separate this genus from Siren. The peculiarities found 

 in the branchiae are shared by the latter genus. But one species of 

 Pseudobranchus is known. 



PSEUDOBEANCHUS STEIATUS Leconte. 



Gray, Aim. Pliilos., 1825, p. 216; Gray, Cat. Batr. Grad. Brit. Mus., ed. i, p. 

 69 ; Bouleuger, Cat. Batr. Grad. Brit. Mus., ed. ii, 1882, p. 87. 



Siren striata Leconte Auu. Lye, N. Y.,' 1824, p. 52, PI. 4; Tschudi, Batr., p. 98. 

 Holbr., N. A. Herp., v. p. 109, PL 36; Dum. & Bibr., PI. 96, fig. 1. 



This species is much smaller than the Siren lacertina, and differs from 

 it in a good many characters. The body is cylindric, and the tail meas- 

 ures two-thirds the length of the head and body and a little more. The 

 head viewed from above has a rather narrow oval outline, and its ex- 

 tremity is rounded without truncation, or sometimes acuminate. In 

 profile the front descends regularly to the end of the muzzle, which 

 overhangs the mouth by a little. The eyes are quite distinct, though 

 small, and are on the border of the head when viewed from above, but 

 have more upward than lateral direction. The mouth is very small and 

 does not extend so far posteriorly as the anterior border of, the eye. 

 The upper lip is pendulous, overlapping the lower, so as to reduce the 

 mouth when closed to a small aperture on the middle line in front. 

 The lip of the lower jaw is not recurved, and there is no groove pass- 

 ing around the chin. The external nostrils are in the upper lip, not 

 very near its edge, but they are not visib'e from above. The distance 

 between them is three-quarters the length of that between the eyes. 



The parasphenoid series of teeth are but little in contact in front, and 

 each one consists of two or three rows. They extend anteriorly near 

 to the premaxillary and posteriorly to opposite the rictus oris. The 

 choante are round, and are at the external side of the parasphenoid 

 series, one-fifth the distance anterior to their posterior extremity. The 

 tongue is narrowed and acuminate in front, and its free portion is rela- 

 tively longer than in the Siren lacertina. 



The branchiie have not the same character as those of the Siren lacer- 

 ima, being tripinnate on the external side only. The first is much 

 shorter than the second, which is shorter than the third. The single 

 fissure is below the base of the second. I have not found a second 

 fissure in this species, nor have I found this one closed in individuals with 



