234 OPHIDIA. 



largest ; nostrils lateral, no pit between them and the 

 eyes ; subcaudal plates double. 



Pelias Berus. 



Pelias Berus, Dum. et Bib. vol. vii. p. 1395 ; Buon. Faun. Ital. 



(figui'ed) ; Bell, Hist. Brit. Eep. 

 Pelias chersea, Buon. Faun, Ital. 

 Vipera Berus, Sciiinz, Europ. Faun. vol. ii. p. 53. 

 The Viper, or Adder. 



Description . — The head is somewhat depressed, almost 

 oval, slightly widening behind the eyes ; gape as long as 

 the head, ascending behind ; no teeth in the upper max- 

 illary bones except the poison-fangs ; a row of small teeth 

 on the palatine bone on each side; neck rather smaller 

 than the back of the head ; body increasing to near the 

 middle, scarcely diminishing to the vent; tail becoming 

 almost abruptly smaller, tapering, pointed at tip, not more 

 than one -eighth of the entire length of the animal ; head 

 covered with small scaly plates, regular in some specimens, 

 but often irregularly disposed ; the central and two occi- 

 pital plates are the largest ; scales of the back and sides 

 suboval, imbricated, and distinctly keeled, forming eighteen 

 longitudinal rows ; ventral plates, 140 to 150 ; subcaudal, 

 about thirty-five pairs ; the ground colour varies con- 

 siderably, sometimes being olive, sometimes deep brown, 

 or dull yellow, or pale grey ; along the back, from the 

 neck to the tail, is a waved wide line of dark brown or 

 black ; sometimes, instead of this line, there is a row of 

 irregular angular spots, having their greatest length across 

 the animal; these spots again, in some specimens, are 

 joined by a narrow line ; on either side of this dorsal line 

 of spots there is frequently a series of dark grey or black 

 marks, alternating with those on the back; and below these, 

 near the junction of the ventral plates with the scales of 



