June 1, 1894.] 



KNOWLEDGE. 



141 



instances, which is perhaps the most striking example of 

 parallelism that can be adduced. The extraordinary 

 feature, to our mind, in the case is the eventual general 

 similarity of structure which has been attained in the 

 three instances — a simUarity which appears difficult of 

 explanation on the ordinary theories of evolution. 



Coming to the last section of our subject, we have to 

 indicate how snakes may be distinguished from lizards, 

 and to add a few words as to the relations of the two 

 groups. We have seen that neither the structure of the 

 vertebrae nor the presence or absence of shields on the 

 lower surface of the body will suffice to distinguish 

 between the two groups ; and it may be added that 

 neither will the forked and retractile tongues of the snakes 

 serve our purpose, since a similar structure is possessed 

 by certain lizards. It has, however, been already men- 

 tioned that none of the snake-like limbless lizards have 

 the additional articular surfaces characterizing the vertebra 

 of snakes ; and to this it may be added that none of the 

 former have the tongue capable of being retracted into a 

 sheath at its base, in the manner distinctive of snakes. 

 An infallible, though not very important, point of distinction 

 between snakes and lizards is to be found in the circumstance 

 that whereas in the latter the two branches of the lower 

 jaw are always imited by suture, in the former the bond 

 of union is a ligamentous one ; and there are also certain 

 other points of distinction, into the consideration of which 

 it will be unnecessary to enter. 



The structural differences in regard to the vertebrae and 

 tongue, coupled with the circumstance that there is more 

 than a single group of lizards, render it pretty certain 

 that snakes are not the final result of the modification of 

 ordinary lizards into snake-like forms. The snake-like 

 lizards may accordingly be regarded as a kind of bad 

 attempt to evolve a snake, since these creatures are by no 

 means numerous, and have not thriven and multiplied 

 after the manner of the true snakes. Whether, indeed, 

 snakes as such have taken origin from reptiles which 

 would be included by zoologists among lizards is more 

 than doubtful, although palieontological evidence is, im- 

 fortunately, very imperfect on this point. Both groups 

 are, however, of considerable antiquity, true snakes of 

 large size, and apparently as specialized as existing forms, 

 dating from the London clay, while bones which have 

 been referred to lizards occur in the Cambridge greensand. 

 Possibly the nearest approach to the common ancestral 

 form is a certain small lizard-like reptile from the English 

 chalk known as Dulichosaurus, differing from existing 

 lizards by the greater number of vertebriB in the neck and 

 the more simple structure of the feet, and having snake- 

 like vertebriP. Should this be the case, it would seem 

 that ordinary lizards have lost the additional articulations 

 characterizing the vertebra of serpents. 



THE WOOD-PIGEON. 



By H.UJRY F. WiTHERBV. 



THE wood-pigeon (Columba palumbus) is the largest 

 representative of the genus Columba to be found 

 in Europe. 

 It occurs plentifully throughout England and 

 Scotland, and remains in the wooded and sheltered 

 districts all the year round, but is only a summer visitor 

 iu the more northern parts of the kingdom. In winter 

 wood-pigeons congregate, and go about the country in 

 flocks, which are no doubt largely augmented by numbers 

 of birds which come over fi'om the Continent. 



The wood-pigeon is sometimes called the ring dove, on 

 account of the white feathers which form a partial ring 

 round its neck. It is naturally a very shy and wary bird, 

 and it requires careful stalking to get a shot at one in the 

 daytime ; but they may be easily shot in the evening, when 

 coming home to roost in the trees. It is sought after on 

 account of its destructiveness to crops, as well as on 

 account of its flesh, which is very good eating as a rule; 

 but at the time of the year when turnip-tops form its chief 

 food, its flesh has a disagreeable flavour. 



Although a very shy bird, the ring dove may often be 

 seen in the London parks, especially in St. .James's Park, 

 where it even breeds. In the summer months I have seen 

 as many as ten together, feeding on the piece of grass under 

 Lord Beaconsfield's statue in Parliament Square, opposite 

 Westminster Abbey. Here they seem quite at home, and 

 take no notice of the people or traffic, and although there 

 is always a large flock of dovecot pigeons close to them, the 

 two species keep quite separate from each other. The ring 

 dove becomes comparatively bold in gardens, and destroys 

 a large amount of fruit in the summer months. It is 

 especially fond of currants, pears being also a favourite 

 dainty ; but its ordinary food consists of buds and young 

 green leaves, beech-mast, acorns, and grains of various 

 kinds. Wood-pigeons swallow the^r food whole, and as 

 many as ten perfect acorns have been found in the crop 

 of a single specimen. When drinking, the ring dove does 

 not take short sips like other birds, but satisfies its thirst 

 in one long draught as a horse would. 



Its mode of alighting is very elegant. It descends with 

 a headlong swoop until within about two feet of the 

 ground, when suddenly it checks its rapid motion by 

 reversing the position of its head, and spreading out 

 wings and tail, drops gently to the ground. It is when 

 in this position that the tail is best seen, for it is then 

 spread out hke a fan, so that every feather is visible. 



Its note is very plaintive and resembles the syllables " coo, 

 coo, coo, coo," the first two and the last being long, whilst 

 the third is very short. The number and length of these 

 syllables are occasionally varied. This note may be 

 heard at all times of the day in a neighbourhood frequented 

 by wood-pigeons, and from its plaintiveness the bird is 

 supposed to have received the name " Queest." In some 

 parts of the country, however, it is called the cushat, a 

 name the derivation of which is imcertain. 



The ring dove's nest is of the frailest description ; it is 

 formed for the most part of sticks, while occasionally a 

 few roots and feathers are placed on the top of these to 

 do duty for lining. The nest is always very flat, and 

 is sometimes so lightly put together that the eggs or 

 young may be seen from below. It is generally built in 

 small trees in woods and plantations, and is thus pro- 

 tected from the wmd. Occasionally, however, the nest 

 may be found in more open situations, and in this case it 

 is built more compactly and is much stronger than when 

 placed in a sheltered spot. The nest represented in the 

 accompanying illustration is a good example of those found 

 in isolated trees exposed to the full force of the wind. 

 The nest is built at a height from the ground varying 

 from six to forty feet. When the bird has been sitting 

 some few days, the top of the nest assumes a whitish 

 appearance arising from a white powder in the bird's 

 plumage. 



The eggs are pure white, and two in number. Two or 

 three broods are reared in a season, the first eggs being 

 laid in April, or even in March, and a wood-pigeon has 

 been found sitting on two eggs as late as September. 



The young are hatched in seventeen days ; they are 

 at first covered with yellowish down, and their eyes 



