_Habits._--This is a far more aquatic species than the preceding, being seldom found in summer away from the water, in which it swims and dives to perfection; which does not prevent it from being equally agile on land. In accordance with these thoroughly aquatic habits, it feeds mostly on fish, although occasionally taking frogs and toads and their tadpoles. Small fish are swallowed in the water, but large ones are landed. This snake does not object to salt water, and it has been observed on the seashore near Odessa, chasing small fish, mostly gobies, in shallow water. Hibernation and pairing take place on land, and it is not until the latter function is accomplished that the snakes of this species resort to the water, which the females leave again for oviposition. Like the Grass-snake, the Tessellated Snake seldom bites. _Reproduction._--Pairing takes place in spring, when large numbers have been observed to congregate for the purpose. As in the Viperine Snake, a second pairing may occur in the autumn, Dr. Werner having found a pair in copula on September 14, at Trebinje, Herzegovina, the female laying her eggs in the following July, which with the beginning of August is the time for oviposition. The eggs measure a little over an inch in length and two-thirds of an inch in width, and number 5 to 25; they are deposited under stones, in the fissures of walls and rocks, or under the refuse of tanneries. 5. TROPIDONOTUS VIPERINUS, Latreille The Viperine Water-Snake _Form._--Moderately slender; head shorter than in the preceding species; snout obtuse, not prominent; eyes and nostrils directed upwards and outwards, the former rather small, the latter somewhat valvular; tail four to six times in the total length. [Illustration: FIG. 18 (after Sordelli)] _Head-Shields._--Rostral broader than deep, visible from above. Nasal usually semi-divided. Internasals as long as broad or longer, subtriangular, truncate in front, as long as the prefrontals. Frontal usually broader than the supraocular, once and a half to twice as long as broad, as long as or slightly longer than its distance from the end of the snout, shorter than the parietals, not in contact with the preocular. Loreal as deep as or a little deeper than long. One or two preoculars and two (rarely three) postoculars. Temporals 1 + 2 or 1 + 3. Upper labials seven (rarely eight), third and fourth (or third, fourth, or fourth and fifth) entering the eye. Four (rarely five) lower labials in contact with the anterior chin-shields, which are usually shorter than the posterior. _Scales_ with two apical pits, in twenty-one (rarely nineteen or twenty-three) rows, strongly keeled, of outer row smooth or feebly keeled. Ventrals 147 to 164; anal divided; subcaudals 46 to 72.