30 VENOMOUS SNAKES AND THE PHENOMENA OF THEIB VENOMS 



Subfamily VIPERIFLSE Boulenger. 

 Stejneger's Cobridae. Cope's Atractaspididae, Causicte, and Viperidie together. 



There is no fossa in the external side of the maxillary bone, between the eye and 

 the nose, as in Crotalinae. The vipers are entirely restricted to the Old World, 

 ranging over the whole of Europe, Africa, and Asia, except Madagascar. Their 

 northern extension is limited only by the permanendy frozen condition of the ground. 

 Nine genera with about 40 species are known. The head and neck are distinct, 

 covered with small scales, with or without frontal plates and parietals. Eyes small 

 with vertical pupils. Body cylindrical. The scales keeled, with apical fossa, in 

 from 19 to 31 rows. Tail short, subcaudals in two rows. 



Genus VIPERA Laurenti. 

 Vipera berus s. Pelias berus. (Plate 12, A.) 



This is the common European viper. The upper jaw not turned at the end; 

 scales of body form 21 rows. The coloration is very variable. Usually the gray, 

 yellowish-olive, brown or red ground-color is set off by a dark zigzag band along 

 the back. The belly is gray, brown, or black, or speckled. The end of the tail is 

 usually yellow or red. Some males are black, through extension of the black mark- 

 ing or through darkening of the ground-color. Males usually are darker and deeper 

 in black markings, with the ground-color lighter, and are mosdy somewhat smaller 

 than the females. ^jj -yj 



The viper prefers heaths, moors, and mixed woods with sunny slopes. Brambles, 

 clumps of netties, hedges, the edge of small copses, and heaps of stones, are favorite 

 places of retreat, affording shelters, and being also the resorts of mice, which form 

 its chief sustenance. At harvest time it is often found in cornfields, and it frequently 

 hides in the sheaves of grain. Vipers are fond of basking on certain spots: on 

 the top of stones, the stump of a tree or a strip of sand; a shower of rain or even 

 passing clouds driving them back into their holes. They are nocturnal and a fire 

 attracts them. They can not climb, and, if they can avoid it, do not go into water. 

 They hibernate for about six months, and a number in the same place. 



This species reaches a length of about 2 feet. It has a wide range, from the 

 British Isles to Saghalien Island and from Caithness to the north of Spain, and 

 the intermediary countries and districts. It ascends the Alps to an altitude of 6,000 

 feet. In captivity it refuses to eat. Its food consists of small birds, frogs, lizards, 

 and sometimes fishes. Its bite is sometimes fatal to human beings, and especially 

 to children, but is not often so. 



Vipera aspis. 



The asp of the Mediterranean is a more southern and western European viper. 

 The muzzle is slightly turned upwards. The top of the head is usually covered 

 with small scales. The coloration is very variable: gray, yellowish, brown, or red 

 above with zigzag band, usually a U mark on the occiput, and longitudinal black 

 bands from back of eyes; belly yellow, white, gray, or black, with a somewhat 

 lighter space. Length 2 to 2.5 feet. France, southern parts of England, Pyrenees, 

 Alsace-Lorraine, Black Forest, Switzerland, Italy and Sicily, Tyrol. 



Vipera ursinii. 



Color yellow or pale brown above, gray or dark brown on the sides, sometimes 

 uniform brown, with more or less regular oval, elliptical, or rhomboid speckles; 

 white stripe along vertebral column; two or three longitudinal series of speckles, 

 dark brown or black on sides; chin and throat yellow; belly black with grayish or 

 white cross series of spots. No sexual difference in coloration. Length about 

 1.3 to 1.6 feet. Southeastern parts of France, Italy > Istria, Bosnian mountains, 

 plains of lower Austria, Hungary. 



