546 The Philippine Journal of Science 1923 



from the angle of the mouth up to the median dark line behind 

 the U-shaped mark. The three or four scale rows on either 

 side of the median dark stripe vary from brownish cream in 

 the young to dark brown in the adults; in many specimens 

 the stripes can scarcely be distinguished from the lateral colora- 

 tion which is a purplish or lavender-brown. 



Only one specimen in the Bureau of Science collection from 

 southern Negros has a single anterior temporal, but the second 

 temporal is separated from the postoculars by only a very short 

 distance. A second specimen from the same locality has the 

 temporal formula 2 + 2, which is the normal one. Fourteen 

 specimens in my collection are from the following localities: 

 Balbalin, Kalinga Subprovince; Polillo Island; Los Banos, La- 

 guna Province; and Oriental Negros. 



Hurria rynchops (Schneider). 



Hydras rynchops Schneider, Hist. Amph. 1 (1799) 246. 



Hurria rynchops Taylor, Snakes of the Philippine Islands (1922) 111. 



There appear to be two varieties of this species, characterized 

 by the presence of two or three prefrontals. The specimens 

 in my own collection and in that of the Bureau of Science vary 

 as follows: 



Specimens from Bantayan (29), Negros (2), Jolo (2), Leyte 

 (1) have only two prefrontals, with the anterior labial not 

 broken, leaving a "subnasal" scale. 



Specimens from Los Banos (2), Luzon (5), Manila (4), Po- 

 lillo (1), Camiguin, Babuyan Islands (1) have the anterior 

 labial broken, leaving a "subnasal," a median prefrontal, making 

 a total of three prefrontals. Save for this character I have 

 not discerned any stable character which is constant throughout 

 the two groups of specimens. There are differences in color, 

 but these are not constant. 



With my limited material I have hesitated to name the Luzon 

 form. If the variation occurs throughout the island, it would 

 be worthy of designation by name. If Gray's Cerberus unicolor 

 described from the Philippines belongs to this form, that name 

 will be applied to the form. The name would fit the coloration 

 of the Luzon form. However, my specimens from Jolo having 

 only two prefrontals are also uniformly colored. So it is difficult 

 to say to which of the above-mentioned groups C. unicolor 

 should be assigned. 



