XII] DIPLOPODA 231 



taken by certain outgrowths from the proctodaeum, called after an 

 Italian anatomist Malpighian tubules. In Lithobius there are 

 two such tubules, blind at their free end, and at the other opening 

 near the hind end of the alimentary canal (6, Fig. 95). Their walls 

 contain traces of uric acid and urates which they have taken up 

 from the blood and which they presumably excrete through the 

 alimentary canal. 



The last-named organ is a straight tube which runs from one 

 end of the body to the other. A pair of salivary glands pour their 

 secretion into it near the mouth, but no other digestive glands exist. 

 Lithobius is carnivorous, living chiefly upon insects, their larvae and 

 earthworms. 



A large part of the space in the head is occupied by the bilobed 

 brain which supplies the antennae and the mouth appendages. 

 This brain is connected by means of a nerve collar with a long 

 ganglionated ventral cord which supplies nerves to the legs and the 

 rest of the body (Fig. 95). 



Centipedes are bisexual, the ovary and testis are continuous with 

 their ducts which open to the exterior on the ventral surface of the 

 last segment. 



Order II. Diplopoda. 



The second large subdivision of the Myriapoda is well illustrated 

 by the black "Wire- worm," lulus terrestris, very commonly found in 

 Great Britain curled up under stones or burrowing in the soil, where 



FIG. 96. lulus terrestris, sometimes called the "Wire- worm." From Koch 



x about 3. 



1. Antennae. 2. Eyes. 3. Legs. 4. Pores for the escape of the 

 excretion of the stink-glands. 



it is said to do much damage by gnawing the tender roots of 

 plants, for all Diplopods (Gr. SurXoos, double) are vegetarians. 



The Wire-worm is a black, shiny cylindrical animal with an 

 enormous number of legs, in spite of which its movements are much 

 slower than are those of Lithobius. The terga or dorsal shields are 

 in this sub-group very much enlarged, whilst the sterna or ventral 



