VIPERTD^. 211 



Eostral nearly as deep as broad ; frontal as long as broad or a 

 little longer than broad, longer than its distance from the end of 

 the snout, much shorter than the parietals ; prsefrontal entering 

 the eye ; loreal separated from the eye by one or two praeoculars ; 

 one or two suboeulars, sometimes fused with the postocular; 

 temporals 2 + 2 or 3 ; 7 (rarely 8) upper labials, none entering 

 the eye, last longest ; 3 pairs of large chin-shields, anterior longer 

 than broad and in contact with the symphysial. Scales in 15 

 rows, smooth, vertebrals not enlarged. Ventrals 136-159 ; anal 

 entire ; subcaudals 37-47. Brown or dark grey above, with 

 irregular transverse series of black and white spots ; a whit© 

 nuchal collar usually present; lower parts white, spotted or dotted 

 with black, at least on the sides. 



Total length 350 millim. ; tail 57. 



Southern China to Malay Peninsula. Eecorded from Jalor and 

 Kelantan. 



Called Ular Icapah at Biserat, Jalor. 



Family VIPERID^. 



Facial bones movable ; prsefrontal bone not in contact with 

 nasal ; ectopterygoid(trauspalatine) present, extending to mandible ; 

 supratemporal present, attached scale-like to the skull and sus- 

 pending quadrate ; maxillary much abbreviated, erectile perpen- 

 dicularly to ectopterygoid, supporting a pair of large poison-fangs 

 without external groove. Mandible without coronoid bone. 



Poisonous snakes including terrestrial, semiaquatic, arboreal, 

 and burrowing types. In the Malay Region the passage from 

 terrestrial to arboreal types is so gradual as to preclude their 

 being referred to distinct genera. With a few exceptions, the 

 Viperidce are ovoviviparous. They are mostly semi-nocturnal. 



Many of the Vij)erid(e are among the most dangerous poisonous 

 snakes, but the Malayan Lachesis have comparatively small poison- 

 glands, and it has been repeatedly ascertained that their bite 

 does not produce death in man and large animals. The physio- 

 logical action of Yiperine poison is very different from that of the 

 Colubrines of the Indian and Malay regions. It brings about 

 coagulation of the blood and clotting of the pulmonary arteries, 

 but its effect on the nervous system is not great and no individual 

 group of nerve-cells appears to be picked out, and the effect upon 

 respiration is not so direct. The influence upon the circulation is 

 more striking than the effect upon the respiration, and the great 

 depression which is a symptom of Viperine poisoinng may be 

 explained in this way. 



The Viperidce are divided into two subfamilies, according to the 



p2 



