14G ON THE PHYSIOGNOMY OF SEKPENTS. 



iiatcd scales, disposed in 21 roAvs ; by a slender tail ; and 

 by tints of a yellow, verging sometimes to brown, some- 

 times to green.. The head is of a brownish-red, and its 

 posterior parts often dark coloured, while the abdomen is 

 yellowish : the female has the lower part of the head reddish. 

 The eye is large, and bordered posteriorly by three plates. 

 Inhabits marshes in deep forests, and in manners ap- 

 ])roaclies the Tropidonotus. 



17. Coluber Can us, the only species of the genus 

 known in southern Africa, in its organization resembles the 

 Psammophis, or sand-serpents ; head small and conical ; 

 muzzle terminated by a salient, vaulted plate ; eyes rather 

 large ; scales snudl, truncated at the top, smooth, and dis- 

 posed in 27 rows ; tail short and thick. Its anatomy 

 presents several curious particulars : the penis is double 

 at each side, the cranium has the form of that of the Hcr- 

 petodryas, the mastoid bones are extremely large, and the 

 strong teeth become longer towards the extremity of the 

 muzzle. Size large, even six feet. S. 194 + 64. This 

 curious species is also remarkable for the changes which 

 the colours undergo by age — pale reddish-brown, relieved 

 by four ranges of ocellated spots, in the young ; grey, in- 

 clining to olivaceous, or to brow^n or black, in the adult. 



18. Coluber Sayi. From Missouri. Head very conical ; 

 vertical plate triangular in form ; rostral salient ; 25 rows 

 of carinated scales ; reddish-yellow, the back a deep 

 brown; these colours form spotted bands. S. 224+55. 



19. Coluber quaterradiatus. Sometimes of the 

 length of seven or eight feet ; lives in the south of Europe ; 

 head distinct from the trunk, very elongated, high near the 

 eyes ; muzzle thick ; eye large, overshadow ed by a pro- 

 jecting plate ; occipital plates pointed ; tail strong ; 25 

 rows of small lanceolate scales. S. 212 + 75. Above 

 brown, relieved by four brown rays more or less distinct ; a 

 dusky ray passes from the eye to the angle of the mouth. 

 This Coluber is very gentle in its manners. 



20. Coluber viridiflavus. From the same regions 

 as last, but of a larger mould, more widely distributed, and 

 more common. Tail very slender, and flat below ; trunk 

 almost cylindrical; abdomen convex; 19 rows of smooth 



