590 



Marvels of the Universe 



ODD" AND -EVEN" IX NATURE 



BY W. P. PYCRAFT, F.Z.S. 



Ix the animal world, what the text-books call bi-lateral symmetry may be regarded as the rule 

 That is to say, their bodies may be divided longitudinall}' into similar right and left halves. But 

 among whole groups of animals this symmetry is conspicuous by its absence. As, for example, 

 among the univalve moUusca — whelks, snails, etc. — where the shell is spirally coiled. Higher in the 

 scale of animal life, from the fishes upwards, " bi-lateral sj'mmetrv " is the rule. But there are 

 some striking exceptions. Among the birds we have the little ^Vr^•-bill Plover of New Zealand, 



in which the beak is sharply 

 turned to the right, a device 

 enabling the bird to pick out 

 small Crustacea from under 

 stones. Among the owls there 

 are some quite extraordinary 

 cases of " asymmetry," for 

 among certain species the 

 aperture of the ear differs 

 either in size, or shape, or 

 both, on the two sides of the 

 head. In the Long- and in 

 the Short-eared Owl, for in- 

 stance, this aperture is of enor- 

 mous size, and is divided b\' 

 a pleat of skin into two 

 chambers. On the right side 

 of the head, as mav be seen 

 in our photograph, the aperture 

 of the ear lies low down in 

 the lower chamber, the upper 

 one being blind. On the left 

 side this condition of things 

 is reversed, the blind cavitv 

 being below, the passage to 

 the inner ear above ! In the 

 rare Tengmalm's owl this 

 asymmetrj' extends even to 

 the skull itself, the bony walls surrounding the passage to the inner ear being strikingly different 

 on the two sides of the head. 



/■V''.-' Ill'] [ir. Sflrilh' K'-nl. 



A CHA.MELEOX. 



The Chameleon is proverbial for ils ability to change colour. But this is only 



true %vithin certain limits, and is due to a shifting of colour-cells bacttwards and 



forwards to the surface of the sltin. The tints it can assume range from \vhite and 

 black to green, yello^^^ bluish-grey and red-bro%vn. 



FAIRY RINGS 



BY EDWARD STEP, F.L.S. 



Among the common objects of the country that are always somewhat of a mystery to most of those 

 who have observed them are the weU-defined rings that often make their appearance in meadows 

 and pastures. They are of ^'arious sizes and differ in the degree of their completeness. The smaller 

 ones are usually complete rings, but the largest maybe only half, or a mere segment of a circle. These 

 started as small circles some years ago, and increased each season, until they met with part of other 



