IV. On the Characters of the Common Viper. 



VIPERA COMMUNIS. 



This animal is found over the greater portion of the tern' 

 perate parts of Europe, and is subject to such great difle^ 

 rences in colour, that its varieties have been described as 

 distinct species by several authors. I was led to suspect 

 this to be the case at a very early period, and have there- 

 fore taken every opportunity of collecting specimens of 

 each variety, with a view to clear up all doubts on the sub- 

 ject. During a long residence in the Western Isles, where 

 this animal is found in the greatest profusion, I obtained a 

 series of the intermediate varieties that most satisfactorily 

 connect all the supposed species, and prove them tobebirt 

 one,— of which the following is the character : 



V'lpera communis, 



Squamis dorsalibus ovatis, linea elevata longitudinal! ; 

 squamis lateralibus inferioribus simplicibus subangulatis. 



Color cinerascens, griseus aut rufescens, lateribus nigro- 

 maculatis ; maculis utroque in lineam longitudinalem 

 digestis, dorso linea nigra utrinque serrata, (e maculis 

 rhomboidalibus confluentibus effecta) ; squamis ventra- 

 libus subcaudalibus intense plumbeis, rarius pallido- 

 irroratis. 



Variat dorso lateribusque intense^ nigris aut perfuscis. 

 Huic speciei referendas sunt species sequentes: Coluber, 



l.Berus, 2. Chersea, 3. Aspis, 4. Prcster Z/w;?tf /, 5. ca:- 



ruleus, Shepp. (Trans. Linn. Soc. 7, 56.), et (7. rufescens 



fiut rufus Museorum Britannia:', 



