131 



Phrynonax poecilonotus (Giinther). 

 A typical example from near Gatun, Canal Zone, collected by a 

 soldier of Fort Davis. 



Phrynonax shropshirei, sp. nov. 



Type. — No. 18819, Museum of Comparative Zoology, an adult male from 

 the vicinity of Gatun, Canal Zone of Panama. 



Paratope. — No. 18820, Museum of Comparative Zoology, from Fort Sher- 

 man, Canal Zone, collected by Mr. J. B. Shropshire, Chief Sanitary Inspector, 

 U. S. Army, Canal Zone. 



Description. — Sixteen maxillary teeth, posterior slightly enlarged; anterior 

 mandibular teeth longest; diameter of the eye one-half as long as its distance 

 from the end of the snout, 7 :14. 



Rostral slightly wider than deep (8:7), just visible from above; internasals 

 two-thirds as long as the prefrontals (4:6); frontal as long as wide (10:10), as 

 long as its distance from the end of the snout, a little shorter than the parietals 

 (10:12); loreal a little longer than deep (3:2); one preocular forming a suture 

 with the frontal; two postoculars; temporals 2 + ; seven (right) and eight (left) 

 upper labials, fourth and fifth or fourth, fifth and sixth entering the orbit, 

 eighth very much the longest ; seven to eight lower labials in contact with the 

 anterior chin-shields which are much shorter than the posterior (10 :17) . Scales 

 in 25 rows (21-24-25-24-21-19-17-15), the three median rows feebly keeled. 

 Ventrals 211, obtusely angulate laterally; anal entire; subcaudals 116-|-n 

 (113p.-|-3-(-n), divided. Blackish brown above, irregularly barred with yel- 

 low, dorsal scales either entirely black or black-edged; head dark brown above, 

 wide border on upper lip yellow, above blackish. Lower surface yellowish, 

 gradually changing to almost clear black posteriorly, including all of the taU; 

 ventrals on anterior portion of body dark-edged. Total length 1630 mm.; 

 tail 430 mm. 



The paratype, also an adult male, has eight upper labials of 

 which the fourth, fifth and sixth enter the orbit; six or seven lower 

 labials in contact with the anterior chin-shield; ventrals 215; 

 anal 1; caudals 93 pairs+n. 



The general coloration of the paratype is somewhat lighter 

 than that of the type but the pattern is exactly the same. Total 

 length 1460 mm.; tail 330. 



Tretancrhinus nigroluteus Cope. 



Two specimens, No. 2717, Museum of Comparative Zoology, 

 collected by Dr. G. A. Maack at Bas Obispo (now under Gatun 

 Lake) show the prefrontals completely divided in both cases. 

 So also, in No. 826, Museum of Comparative Zodlogy, from San 

 Juan del Norte, Nicaragua, which is the type of Helicops agassizii 

 Jan. Two recently acquired examples likewise show this condi- 

 tion to a lesser degree in that the prefrontals are only partially 

 divided. These two are No. 18,812 from near Fort Sherman near 

 Colon and No. 18,818 from Fort Randolph also near Colon. 



According to Boulenger, T. mocquardi Bocourt, has but a 

 single prefrontal while in nigroluteus it is supposed to be double. 

 Moreover, in T. mocquardi the scale-rows are said to be 19 while 

 in nigroluteus they are 21; so also, the preoculars are said to be 



