( 



210 JOURNAL, R.A.S. ( CEYLON). [VOL. XI. 



B = 47 Hydrus platurus. 



Nostrils provided with a valve placed on the upper 

 surface of the snout. 46 to 56. 



C = 34 Chersydrus granulatus. 



Nostrils placed close together high on the snout, 

 opening forward ; provided with a valve. 



MOUTH. 



A = 24 Zamenis mucosus. 



Terminal ; cleft in accordance with length of head ; 

 jaws very dilatable ; labial margins simple. 3 to 33, 

 35 to 45, 57 to 60. 



B = 47 Hydrus platurus. 



As in a ; labial margin with a lobule in the middle of 

 the rostral shield, and with a notch each side, through 

 which the forks of the tongue can be protruded. 46 to 56. 



C = 34 Chersydrus granulatus. 



As in a ; labial margin with a lobule in thecentre of 

 lower lip, fitting into a notch in the rostral. 34. 



D 1 Typhlops braminus. 



Mouth inferior, very short and narrow ; jaws scarcely 

 dilatable. 1, 2. 



TEST II. 



A = 24 Zamenis mucosus. 



All the teeth solid, none grooved, placed on the maxil- 

 laries, palate, and mandibles ; conical, sharp, recurved. 

 1. — Maxillary teeth increasing in size posteriorly ; the last 

 not so long as some of the preceding. 24 Z. mucosus ; 

 25 Z, f asciolatus ; 29 T. ceylonensis ; 33 H. schistosus. 



