No. 39.— 1889.] 



ZOOLOGICAL TABLES. 



203 



F = 4 Cylindrophis maculatus. 



Scales surrounding the whole body (i.e., there are no true 

 ventrals), smooth, highly polished, slightly imbricate. 



1. — A series of ventral scales slightly larger than the 



adjoining ones. 4. 



2. — No large ventral series. 1, 2. 



G = 6 Rhinophis oxyrhyncus. 



As in /, but there is a rough naked disc on the end 

 of the tail. 



1. — Caudal shield as long as the shielded part of the head, 



extending to lower surface of tail ; obtusely rounded 

 caudal scales, smooth. 6, 7, 8. 



2. — Caudal shield less than half the size of the head ; as- 



perous, scarcely ridged in the centre ; faint traces of 

 keels on some of the final caudal scales, and some- 

 times on terminal upper. 9. 



3. — Caudal shield forms a large flat rough disc ; very faint 



traces of keels on terminal sub-caudal scales. 5. 



H — 47 Hydrus platurus.* 



Scales unpolished, surrounding the whole body ; the 

 ventral series as a rule distinguished in some way from the 

 rest ; never strongly imbricate and frequently tessellated. 



1. — All the scales more or less hexagonal, tessellated ; 



smooth in the females and young, with one to three 

 tubercles in the male ; no larger ventral series. 47 

 H. platurus. 



2. — As in h 1 . Scales feebly tubercled or keeled ; those on 



the lower surface in the male with a strong spmose 

 tubercle ; ventrals larger anteriorly, with two spinose 

 tubercles in the male. 46 E. curtus. 



3. — All the scales imbricate, smooth in the young, with a 



central tubercle in the adult ; ventral series feebly 

 enlarged. 48 H. spiralis. 



* The scales of sea snakes are counted round the neck : they are more 

 numerous round the middle of the body. 



