80 PROCEEDINGS OF THE ACADEMY OF 



gastrosteges reaching ISO or 190 ; in the exiguus, 137 is the most that I have 

 counted. The head of the latter is relatively smaller and less distinct, in 

 accordance with the character of Dromicus. D. callilaemus is similar in 

 some respects, but exhibits a broader vertical shield, a more elongate tail, and 

 only seven suptrior labial plates. 



Lygophis r u t i 1 u s . 



Form approaching Ophiomorphus, but the tail is slender, though not long. 

 Scales in nineteen longitudinal rows, rather elongate medially. Head mode- 

 rately distinct, rather short. Rostral plate not low, the nasal borders a little 

 concave. Prefontals as long as broad. Vertical and superciliaries elongate ; 

 the former nearly twice as long as broad, the borders a little concave, scarcely 

 convergent. Occipitals very short. Temporals small, three larger, three 

 smaller. One pre- two postoculars, both in contact with the temporal. Eight 

 superior labials, fourth and fifth entering orbit, all higher than long excepting 

 sometimes the first and last. Inferior labials ten, fifth and sixth largest. 

 Pregeneials longer than postgeneials. Total length 18 in. 10 lin. ; tail 3 in. 

 9 1in. 



Above dark brown ; two yellow lines extend from the anterior extremity of 

 the superciliary shields to the end of the tail, occupying on the body the centre 

 of the scales of the seventh row, being separated by five scales. The median 

 line is occupied by a similar red stripe which is most distinct behind the 

 occipital plates and on the posterior regions. The space between the yellow 

 lines contains two series of black spots which usually alternate, sometimes 

 coalesce. The sides are marked with vertical black spots or bars which extend 

 from the second row to the yellow line, and which are one or two scales apart. 

 Small yellow dots are scattered over these and other parts of the body. 

 Head above black. A yellow line near the inner border of each occipital, a 

 bifurcate one on the vertical, a large one on each pre- and postfrontal, also on 

 each nasal, the loreal, the pre- and postoculars. Labials and chin yellow ; 

 belly deep rose-red, every second or third gastrostege with its posterior angle 

 black. 



Hab. Paraguay, along the Parana River and its branches, in particular the 

 Tigre. Mus. Smithsonian, Washington, (No. 5397.) Acad. Philada. 



In this beautiful water-snake I find a depression near the tip of some of the 

 scales, but nowhere have I discovered a true pore. 



Lygophis flavifrenatus. 



Scales rather elongate, in seventeen longitudinal series. Head slightly dis- 

 tinct, rather elongate. Rostral plate a little produced posteriorly above ; 

 nasal sutures slightly concave. Prefrontals as long as broad. Superciliaries 

 narrow ; vertical elongate, the lateral borders a little concave, posterior 

 sutures short. Occipitals short, much rounded posteriorly, bounded by six 

 temporals which decrease in size from the anterior. The latter is short, in 

 contact with both postoculars and two labials. Eight superior labials, none 

 very high, fourth and fifth (which are longer than high) entering the orbit. 

 Inferior labials ten. Total length 25 in. 10 lin. ; tail 6 in. 10 lin. 



Above brown, inferior two rows of scales tinged with olivaceous. A narrow 

 yellow line extends from the summit of the rostral plate across the superciliary 

 and occipital plates on each side to the end of the tail. It is on the seventh row 

 of scales on the body. Three rows separate these lines ; the scales of the external 

 of the three have their terminal halves black. Tips of scales of the first row 

 black anteriorly ; tips, and finally the whole of those of the third black, form- 

 ing a band on the posterior fourth of the body and tail. Anterior angle of 

 every gastrostege black ; remainder greenish white. Some black spots on the 

 sides of the neck ; oue posterior to the eye prominent. 



Hab. Rio Vermejo region. Mus. Phila. Acad. ; Smithsonian, (Nos. 5397, 

 5398,) Capt. Page's Expedition. 



[Feb. 



