Very closely allied to the preceding, and differing from it only in the following points: Parietals shorter, slightly longer than the frontal, and anal entire. Loreal twice to twice and a half as long as deep. Fourth and fifth, or third, fourth, and fifth, labials entering the eye. Scales in nineteen or twenty-one rows. Ventrals 203 to 235; subcaudals 54 to 70. Grey above, with 35 to 40 blackish spots on the body, the anterior largest and darkest; a lateral series of smaller spots or vertical bars. Lower parts blackish, with small whitish spots and dots. Reaches a length of 3-1/2 feet. This species inhabits the Caucasus, and, being on record from the northern slope (Kuban River), has to be included in the European fauna. It occurs also in Mesopotamia, a specimen from Bagdad being preserved in the British Museum. The young specimen figured on Plate XI. is stated to be from Constantinople. Nothing is known of its habits, which are probably the same as those of _Tarbophis fallax_. FOURTH FAMILY: VIPERIDÆ Maxillary, palatine, and pterygoid bones movable, the first much abbreviated, erectile perpendicularly to the large transverse bone, and supporting a pair of large canaliculated poison fangs; mandible without coronoid bone. No vestiges of pelvic arch. All more or less poisonous, some being among the most dangerous of snakes. Divided into two subfamilies, each of which is represented by one genus in Europe: _Viperinæ._--No pit on the side of the snout; maxillary bone not hollowed out. _Crotalinæ._--A deep pit on each side of the snout, between the nostril and the eye; maxillary bone hollowed out above. _PLATE XII_ [Illustration: VIPERA URSINII _From Zoological Society's Proceedings_] [Illustration: VIPERA RENARDI _From Zoological Society's Proceedings_] [Illustration: VIPERA BERUS _After Sordelli_] The _Viperinæ_ inhabit nearly the whole of Europe, Asia, and Africa; the _Crotalinæ_ are Asiatic (one species extending its range into a small part of South-Eastern Europe) and American. GENUS VIPERA, LAURENTI Head distinct from neck, covered with small shields or scales, with or without distinct frontal and parietal shields; eye moderate or small, with vertical pupil, separated from the labial shields by scales; nasal separated from the rostral by a naso-rostral. Body short. Scales keeled, with apical pits. Tail short. Of the eleven species of this genus, six are found in Europe; two inhabit South-Western Asia, one the Indo-Malay region, and two Eastern Africa.