7 6 ANIMAL BIOLOGY 



smelling secretion. The millipeds are mostly vegetable 

 feeders, and some species are more or less destructive 

 to crops. 



The myriapods in general are lovers of the dark and 

 are commonly found under rocks and logs. Some species 

 are remarkable for the great elongation of the body and 

 the numerous segments composing it. In Geophilus the 

 segments may be over 170 in number. It may have 

 been some such creature that induced Professor Ray 

 Lankester to write: 



A centipede was happy quite 



Until a toad in fun 



Said, "Pray, which leg moves after which?" 



This raised her doubts to such a pitch, 



She fell exhausted in the ditch, 



Not knowing how to run. 



The Arachnida include scorpions, spiders, ticks, mites 

 and a number of other forms which differ 

 very greatly in size, structure and habits. 

 We shall consider first the spiders as they 

 are the most familiar and the most im- 

 portant. Spiders differ from insects in 

 possessing eight legs and in having the 



son gland of spider, head and thorax fused into a single piece. 



N eme si a, with There are usually eight simple eyes, but 



duct and fang. r / , 



no trace of antennae. The head is fur- 

 nished with a single pair of jaws which end in sharp curved 

 hooks at the end of which is the opening of a large poison 

 gland. Behind the jaws are the maxillce, the bases of which 

 are expanded into a sort of lip, the rest of the organ consti- 

 tuting the jointed palp or feeler. Spiders never chew their 

 food; they simply suck out the juices of the prey which is 

 held by the fangs. On the under side of the abdomen near 



