5o6 



THE NATURE BOOK 



Slow Worm an outgrowth from a tail- 

 stump often shows a reversion to imma- 

 ture colouring, the light tint of the upper 

 surface being sharply divided from the 

 black of the lower. 



Individual Slow Worms show remark- 

 able variations of colour, and I am inclined 

 to think that these variations depend more 

 upon age than upon either sex or locality. 



At birth the young Slow Worm (he is 

 born in a membranous envelope from 

 which, after absorbing most of the con- 

 tents of the yolk sac, he frees himself 

 by more or less prolonged struggles) is 

 characterised by the sharp demarcation 

 between the silvery grey of his upper sur- 

 face and the black, or deep copper brown, 

 of his under surface. The whole of him 

 is highly polished. A dark median line 

 runs the length of his back, and forks 

 where it approaches the head. An irregular 

 dark marking between his eyes is some- 

 times separated from this line and some- 

 times produced backwards to meet it. 

 Magnification will show that the median 

 line is zigzag, and that it has its origin 

 in a pigmented line of junction between 

 parallel and dovetailed scales. It never 

 entirely disappears, though in an adult 

 Slow Worm it often presents a herring- 

 bone rather than a zigzag pattern. The 

 silver grey of a young Slow Worm soon 

 changes to a yellow-brown tint, and, as 

 he develops, this tint tends to spread over 

 his sides, and to obliterate the distinction 

 between his upper and his under surface. 

 In adult Slow Worms there is seldom 

 much black to be seen. They may be 

 brown-olive, lead-coloured, copper, or even 

 pink. Melanism may, of course, occur, 

 and albinism also. I have seen several 

 dark specimens with patches of azure on 

 the throat, but, as is the case with blues 

 and greens generally, this colour appears 

 to be structural and fades soon after 

 death. 



Little is known of how the Slow Worm 

 passes his time, but everything points to 

 his appreciation of a quiet hfe. and of the 

 society of his own kind. A Slow Worm 

 may sometimes be found lying wrapt in 

 contemplation in the middle of the high 

 road. It is charity to move him. More 

 often he will be sighted sunning himself 

 before th(i dew is gone, or crossing the 

 field-path after rain, but the Slow Worm 



hunter who depends on such fortuitous 

 encounters will have a light bag. The 

 largest catches occur when one happens 

 on a pile of stones or debris which con- 

 ceals a community. Slow Worms are 

 curiously conservative reptiles. Year 

 after year the same stone shelters them — - 

 they take four or five years to mature, 

 and we may assume them to be long- 

 lived — day after day they sun themselves 

 (weather permitting) in the same spot 

 and at the same time. 



In certain localities one may, on a fine 

 day, find a dozen specimens in as many 

 minutes ; one may visit the same spot 

 on a cold day, turn up the same stones, 

 and not find a single one. As anyone who 

 keeps Slow Worms under reasonably 

 natural conditions will soon discover, 

 they are efficient burrowers in soft soil, 

 and in uncertain weather will often lie 

 with their noses just above ground level, 

 and the rest of them concealed. Their 

 burrows are just of sufficient diameter to 

 admit their bodies. 



Perhaps a Slow Worm's normal lodging 

 (under a stone) is determined by his 

 normal food. This, as was first pointed 

 out by the late Rev. J. G. Wood, consists 

 of slugs. Professor Leighton writes : " The 

 Slow Worm either gradually approaches, 

 or allows the slug to approach him, until 

 the latter is within reaching distance, 

 then poises his body in a delicate curve 

 over the body of the slug, and with a 

 quick movement — the only sign of haste 

 in the whole business — seizes the mollusc 

 by the middle. . . . The slug never 

 takes the slightest notice of the Slow 

 Worm until it is seized." The latter 

 observation should account for the Slow 

 Worm's natural habitat — " ' Will you walk 

 into mv parlour ? ' said the Slow Worm to 

 the Slug." 



Of four-legged lizards we possess two 

 species — the Common Lizard {Laccrta 

 vivipara), and the Sand Lizard {Laccrta 

 agilis). I mention these two scientific 

 names as remarkable examples of in- 

 exactitude, even when due allowance is 

 made for the fact that they belong to an 

 inexact terminology. Lacerta vivipara, 

 if it means anything, means "the lizard 

 which produces its young alive " — a highly 

 creditable quahty, no doubt, but hardly 

 a specific distinction. Zootoca vivipara 



