VARIATIONS OT THE VIPER IN DENMARK. 61 



third) longer than broad, and usually a little shorter than its 

 distance from the end of the snout, as long as or very slightly 

 longer or shorter than the parietals. In one specimen (Viborg, 

 $ ) the frontal is in contact on both sides with the supraocular, 

 in two (Knudskov, <? ) on one side only ; in all the others one 

 series of small shields separates the frontal from the supra- 

 ocular. The rostral is as broad as deep, or slightly (7 : 6 or 8 : 7) 

 broader than deep, or slightly (9 : 8 to 6 : 5) deeper than broad ; 

 it is in contact above with two apical shields, except in 4 speci- 

 mens (Knudskov, $■ , Glamsbjerg, $ , Viborg, $ 2 ), in which 

 the apical is single. Two specimens (Viborg, $ , Knudskov, $ ) 

 have a single canthal on one side ; all the others have two. A 

 single series of scales separates the eye from the labials, except 

 in one specimen (Knudskov, <? ), which has two complete series 

 on the left side, whilst on the right side the two series are 

 separated by a single scale between the eye and the fourth labial. 

 The latter arrangement is also shown on both sides in one speci- 

 men (Skarrild, $ ), and on one side in two others (Knudskov, $ , 

 Glamsbjerg, 2 ). 6 to 12 scales (exclusive of the supraocular) 

 surround the eye, 8 or 9 being the usual number. The upper 

 labials vary from 7 to 10, the two extreme numbers occurring but 

 once ; in 42 cases there are 9 labials, in 60 there are 8 (the 

 number not being always the same on both sides of the animal) ; 

 in 73 cases the fourth and fifth labials are below the eye, in 31 

 cases the fourth only. 



Scaling of Body and Tail. — The scales on the body are in 

 21 rows, except in four specimens : one with 19 (Viborg, <?), one 

 with 20 (Knudskov, <?), and two with 23 (Glamsbjerg, $ , Trust, 

 <?). The ventral shields vary between 135 and 147 in <? , 140 

 and 154 in ? ; the subcaudal shields between 34 and 42 in $ , 

 28 and 38 in ? . 



Size. — The largest male specimen measures 590 millim., the 

 largest female 650. The length of the tail is 6j to 8 times in the 

 total in males, 8 to 9f times in females. 



Coloration. — The same amount of variation is shown as in 

 the British specimens, on which I have previously reported, 

 and the sexual differences are as a rule well marked, males 

 being characterized by the intensity of their black markings; 

 among the latter we likewise find silvery^grey, almost white, speci- 

 mens, with pitch*black markings, the so-called white Vipers, on 



