especially the mice and slow-worms on the hillsides, and the water-voles at the river-side. These three are their staple articles of diet here. The bracken on Garway Hill, which covers a very large area, swarms with mice, which are also of course plentiful in the woods, while the slow-worm is perhaps more abundant across the river. The slopes of this hill are hot and dry and face the south-conditions which we saw were all characteristic of the taste of adders; so that altogether everything is in the adder's favour in the Monnow Valley. But there remains the problem of the entire absence of the ring snake. Without going over the same ground again, it is quite obvious that it is precisely because the conditions are so favourable to the adder that the ring snake is not equally attracted. In particular, the nature of the ground and the food-supply are not suited to its requirements. There are no small streams, few ponds, and therefore comparatively few frogs, the favourite food of the ring snake. Heaps of garden rubbish and manure are few and far between, and the slopes of the hillsides too exposed in winter for the eggs to survive if not hatched out in the autumn. The conditions favouring the ring snake are better found on the southern slopes of The Graig some miles away, and accordingly there Tropidonotus natrix flourishes. It was suggested to me by a naturalist that possibly the adder had exterminated the ring snake here, but I have not been able to obtain any evidence to support this theory; and the fact that the adder is so often restricted to a particular locality in many counties, in addition to what we have seen to account for its presence here, leads rather to the conclusion that it is a case simply of a suitable environment. The result of this investigation into the distribution of the Ophidia in the valley of the Monnow in its course on the South Herefordshire boundary may be summed up thus: 1. That the adder (Vipera berus) is here relatively common. 2. That the average length is 24 inches in the adult male, 25 in the adult female — being much above the average of most localities. 3. That the ring snake (Tropidonotus natrix) is not found, except probably when artificially conveyed thither, and certainly does not breed there. 4. That the smooth snake does not occur. 5. The small red viper has been taken once (by the author), and seen on two other occasions.1 Some such factors as the foregoing must be held to be mainly responsible for the striking ophidian characteristics of this and other localities which present similar peculiarities. There may, of course, be other modifying influences at work, which have either in past times contributed to, or even now are maintaining, the existing state of affairs. 1 Cf. "The Reptilia of the Monnow Valley," Woolhope Club Transactions, 1898-99.-Author. CHAPTER XV. THE SMALL RED VIPER. PLEA FOR ITS RECOGNITION AS A SPECIES-DISTRIBUTION DESCRIPTION-SIZE-VENOMOUS-SUGGESTED NAME. THE small red viper is a reptile far better known to those whose occupations take them to the haunts of snakes than to scientific naturalists. Indeed by the latter its existence is generally ignored. Many works on natural history make no allusion to it, and where it is mentioned it is referred to as a variety of the common adder, or as merely the young of that species. Any departure from those views, if noticed at all, is sure to be severely criticised, if not resented as presumptuous. If, however, an observer is to be true to himself, he must record his observations, and is entitled to deduce conclusions therefrom irrespective of results. Careful study of British adders has driven me to regard the small red viper as a valid species, quite as distinct from the ordinary adder as a swallow is from a martin or a stoat from a weasel. It is a reptile that has had but little attention paid to it, probably on account of its great rarity and its very local distribution, and also, no doubt, because it is very much more difficult to capture than the ordinary adder. The small red viper resembles the common adder in the arrangement of its head-plates and in the number of belly-shields, and is therefore put in the same species. It differs from the adder in most other respects; but the differences, by an arbitrary arrangement, are not regarded as essential. These differences are, however, constant, which to my mind is an all-important point. It has been said that the small red viper is held to be either a variety of the adder or the young of the adder. The latter view is the important one from the point of view of its validity as a species. This opinion presumably is based upon the fact that certain ordinary adders exhibit a red colour. It is assumed that these adders, if they could have been examined when young, would have appeared to be small red vipers. But it so happens that this red colour in ordinary adders is characteristic of one sex only, and that the female. Thus in Mr Boulenger's most valuable paper on the "Variations of the Viper in Great Britain" the following occurs: "Brown and brick-red specimens, with the markings of a more or less dark-brown, are females." This is absolutely true, the colours men 1 Zoologist, March 1892. tioned never being found in the ordinary male adder. The question therefore arises, Are all these so-called small red vipers simply young female adders? This could only be settled by obtaining specimens of this colour of both sexes. I had long believed in the distinctness of the small red viper from the adder, from its constancy in size and colour, but had never taken a male specimen until the 26th April 1901. I was at that time investigating the Ophidia of Central Dorset, and on the day mentioned took a specimen locally known as the little viper. It was the usual red colour, but a glance at the tail at once showed it to be a male. I demonstrated the male organs to the Rev. F. W. Brandreth, to whom I am indebted for the opportunity of examining that most snaky neighbourhood. The length of the specimen was 121 inches. This viper is well known in that locality, though of much less frequent occurrence than the ordinary adder, which is abundant. The male adder there is pale-grey with very black markings and bluish-black belly, not in the least like the small red viper. Moreover, if the red viper were a young female adder, a large number of specimens ought to show the gradations of the one passing into the other. This is not seen in any of the hundreds of female adders I have examined. Distribution.-On account of its infrequent occurrence, and the absence of authentic county records, it |