WATER-MITES AND THE WATER-BEAR. 261 



The skin of most of the forms is soft and easily broken, 

 but in the members of a single genus, Arrenurus, the 

 surface is firm and comparatively hard. They are all 

 brightly, even brilliantly, colored. They may be of one 

 uniform tint, with a few blackish or brownish spots on 

 the posterior region, or the single individual may be 

 variously tinged in different parts of the body. The 

 colors are of almost every imaginable shade of crimson, 

 azure blue, yellow, green, brown, gray, or purple. The 

 eight long legs also share in the general brilliancy, and 

 often present a coloration entirely different from that 

 of the body. 



The eyes are usually on the upper surface near the 

 front border. They are small, and may be either round 

 or crescentic in shape, red, black, or carmine in color, 

 and two or four in number. They are usually placed 

 close together, and when four in number, are arranged 

 in two distinct pairs. 



The upper part or the back of the little animals may 

 be entirely smooth, densely clothed with short hairs, or 

 with a few scattered, fine bristles. It may also present 

 no markings when magnified, or, as in a single genus, 

 Arrenurus, it may be beautifully ornamented with a 

 net-work of narrow meshes in a hexagonal pattern. In 

 all, or nearly all, of the mites the upper surface bears 

 two or more black, dark brown, or reddish spots quite 

 distinct from the general coloring of the body. These 

 are caused by nearness to the surface of the intestine or 

 other internal viscera, the dark contents of which show 



