612 Marvels of the Universe 
and fishing-nets, or whatever offers. Owing to the great number of the ultimate branches, it is no 
easy matter to disengage an Argus when it has got hold of any of these objects. A superficial view 
of the Argus suggests a relationship to the Feather-stars. 
THE BARK-GECKO 
BY R. LYDEKKER F.R.S. 
THAT many animals are coloured to resemble their surroundings, so that by means of this pro- 
tective resemblance they may more or less completely escape detection, is a fact familiar to all per- 
sons who are in the habit of making an intelligent use of their eyes, and more especially those who 
have travelled in foreign countries. Ordinary grasshoppers, tree-frogs and many kinds of tree- 
snakes are, for instance, coloured like the grass or foliage which forms their home; while desert- 
dwelling grasshoppers, snakes, and mice have a brownish livery, mottled with black and yellow, 
to harmonize with the sand and pebbles of their 
surroundings. 
In some instances this general protective tone 
of colouring is intensified and enhanced by the 
development of special markings, as in the case 
of the woodcock and the snipe, whereby the re- 
semblance to surroundings is made much closer 
than would otherwise be possible. One of the most 
remarkable instances of this kind of protective re- 
semblance is presented by a lizard found on trees 
in Madagascar, belonging to the group typified by 
the little Gecko of Southern and Eastern Europe, 
and hence known as the Bark-Gecko. Measuring 
some eight or nine inches in length, these lizards 
are built somewhat on the lines of a miniature 
crocodile, having large and flattened heads and 
broad, depressed bodies, although the tail is pecu- 
Photo bu) (2. Noad Clark. 
THE EGGS OF THE ARGULUS. liar in being short and _ trowel-like, while the toes 
eTiheu Are ulivstevillilassealmannieeiG0 Olerestatientimes terminate in the large disc-like expansions common 
They are deposited in rows, are oval and pale yellow to Geckos generally. 
in colour, while each one is glued to its neighbour a 4 is 
with an albuminous material. They are here shown Such a form of body is, of course, admirably 
under water and magnified twenty times. 
adapted to enable the creature to cling close to the 
bark of its native tree ; but in order to enable it to escape detection when thus posed, its colouring 
is almost precisely identical with that of lichen-clad bark, being a mixture of black and irregular 
streaks and blotches of white and grey. As may be seen in the specimen exhibited in the Natural 
History Museum, many of these light blotches are almost indistinguishable from the patches of grey 
lichen on the tree-bark ; and when viewed from a short distance, almost the only thing that 
attracts attention to the presence of the creature are its large, glaring, yellow and red-streaked 
eyes. Whether when ‘alive the Bark-Gecko closes these betraying eyes at the approach of danger 
does not seem to be known; but possibly they are less conspicuous in nature than in museum 
specimens. 
There appear to be two distinct varieties of these remarkable Geckos, but whether these are 
restricted to different situations is another factor in the economy of the creature of which we are still 
ignorant. In the typical variety the tail is short and broad and the markings less distinctly like 
lichen-clad bark than in the second variety—or Lichen Bark-Gecko, in which the tail is longer and 
narrower. 
