250 OPHIDIA. 



Ptyas koeeos. (Figure, p. 164.) 



Coluber korros (Reinw.), Schleg. Phys. Serp. ii. p. 139, and Abbild. p. 99. pi. 27, &pl. 28. figs. 1-6. 



Cantor, Mai, Rept. p. 74. 

 Ptyas korros. Cope, Proc. Acad. Nat. Sc. Philad. 1860, p. 563. 



Head rather narrow, with the snout of moderate length ; body and tail elongate, scarcely 

 compressed ; eye large. Rostral shield as high as broad ; anterior frontals half as large as 

 posterior ; vertical with the lateral margins convergent, concave, and longer than anterior ; 

 superciliary projecting ; occipitals obliquely truncated behind. Generally two loreal shields, 

 one behind the other ; two prgeoculars : the upper large, concave, extending on to the upper 

 side of the head, but not reaching the vertical ; the lower is small, and evidently a detached 

 portion of the thii'd upper labial ; two postoculars. Eight upper labials, the fourth and fifth 

 entering the orbit ; temporals elongate, 2+2, the anterior being in contact with the post- 

 oculars. Scales rather elongate, in fifteen rows, those of the vertebral series not larger ; 

 they have a pair of apical grooves, and are smooth, but those on the hinder part of the back 

 have an indistinct keel. Ventrals \vithout keel, somewhat bent up the sides, 162-176 ; anal 

 bifid ; subcaudals 97-136. Each maxillary is armed with about twenty teeth, slightly 

 increasing in strength posteriorly. Light or dark brownish-green above, the scales with a 

 darker margin ; those on the hinder part of the trunk and on the tail are edged with black, 

 the edges producing a regular network. Lower parts uniform yellowish. 



This species is very closely allied to Pt. mucosiis ; and, sometimes, it is difficult to decide 

 to which species examples should be referred. Pt. mucosus generally has the scales more 

 strongly keeled, a triple loreal, seventeen rows of scales, black-edged shields of the head, and 

 about 200 ventrals : yet a specimen from Hongkong with three loreals, fifteen rows of scales, 

 and 166 ventrals appears to belong to that species, and not to Pt. korros. Another specimen 

 from Ceylon which we refer also to Pt. mucosus has only one loreal. 



Pt. korros has a more limited range than Pt. mucosus ; it is found in Java and Sumatra, 



Siam, the Malayan peninsula, Arakan, Tenasserim, and Southern China. Its habits are 



similar to those of Pt. mucosus; but we have never seen a specimen more than 69 inches 

 long, the tail measuring 24 inches. 



XENELAPHIS, Gthr. 



Body elongate, not compressed ; tail more than one-third of the total § 



length ; head rather short ; eye of moderate size, with round pupil ; nostril 

 lateral, hetween two plates. Shields of the head regular ; two praeoculars ; 

 one loreal. Scales smooth, without apical groove, in seventeen rows, those 



