Some specimens of this small snake bear a general resemblance to _Coronella girondica_, with which _Macroprotodon_ has sometimes been confounded. But a careful examination of its whole structure shows it to be more affine to _Coelopeltis_ and _Tarbophis_, the other European representatives of the Opisthoglyphous Colubrids. _Size._--The largest European specimen examined measures 17-1/2 inches. Specimens up to 22 inches long occur in Algeria and Tunisia. _Distribution._--In Europe this snake is only known from Spain (Estremadura, New Castille, Andalucia), Portugal (Alemtejo), the Balearic Islands (Majorca and Minorca), and the island of Lampedusa. In North Africa it is generally distributed from the north coast of Egypt to the Rio de Oro; in Algeria it penetrates into the northern parts of the Sahara. The specimen figured on Plate XI. is from Algeciras. _Habits._--Appear to be similar to those of _Coronella girondica_. Crepuscular in its habits, it is usually found under stones or in burrows in the ground. Unless pursued, when it darts off with great rapidity, its movements are slow. It is very ready to bite, but no experiments have been made on the effects of its poison. The food consists chiefly of small lizards. _Reproduction._--All that is known on this head is that, according to Doumergue, eggs are laid in July in Algeria. GENUS TARBOPHIS, FLEISCHMANN Maxillary teeth few, anterior longest, gradually decreasing in size posteriorly, and followed, after an interspace, by a pair of enlarged, grooved fangs, situated below the posterior border of the eye; anterior mandibular teeth strongly enlarged. Head distinct from neck; eye moderate or rather small, with vertically elliptic pupil. Body moderately elongate; scales smooth, oblique, with apical pits. Tail moderate or rather short. The eight species of this genus inhabit South-Eastern Europe, South-Western Asia, and Africa. Two are dealt with here. 19. TARBOPHIS FALLAX, Fleischmann (_Ailurophis vivax_, Bonaparte) The Cat-Snake _Form._--Moderately slender. Head much depressed. Tail five and a half to seven times in the total length. [Illustration: FIG. 32]