MANUAL OF NATURAL HISTORY. 67 



with maxillaiy teeth ; eyes and nostrils superior ; 

 pupils small, round ; hind-limbs not developed ; ven- 

 tral shields narrow, hexagonal, or band-like. Live 

 in water. 



3. Family. — Salt-Water Serpents (Hydrophidas). 



Head usually small, with shields or scales ; 

 belly keeled, with two rows of small seale-like 

 shields, often united together ; nostrils val- 

 vular; tail mostly broad, compressed; colours 

 chiefly green or yellow. Can live only for 

 a short time out of water. Live in the sea 

 or in salt lakes. Venomous. 

 The genus " Achrocordus" is included with this 

 family by Gray, but its tail is conical. It 

 inhabits rivers, and in Manilla and Java, 

 is considered by the inhabitants as quite 

 innocuous. 



4. Family. — Fluviatile- Serpents (Homalopsidae). 



Belly rounded, with more or less broad band- 

 like shields ; head moderate, often depressed, 

 mostly shielded ; tail conical, tapering ; eyes 

 and nostrils small ; colours mostly sombre. 

 Inhabit rivers and ponds. 



III. SUB-ORDER. — Harmless-Serpents (Cohibrina). 



Jaws strong, both toothed ; no poison-fangs ; head 

 moderate or indistinct ; crown at times with regular 

 shields ; tongue very extensible. 



5. Family. — Boas (Boidse). Hinder-limbs rudimen- 



tary, spur -like ; nostrils lateral ; eyes lateral, 

 pupils oblong ; ventral-shields narrow, trans- 



