548 MYRIOPODA. 



ORDER IX. LINGUATULIDA. 



These are worm-like parasites, with jointed bodies and separate sexes. 

 They are curiously intermediate between parasitic worms and Arthropoda, 

 but they are now referred to the Arachnids as an aberrant group. In their 

 embryo state, they have two pairs of short, two-jointed legs, with two strong 

 claws, and two hooks at the mouth. In their sexually mature condition, they 

 have four hooks at the mouth, but no legs. They are met with in the encysted 

 larval conditions in the lungs and liver of the horse, dog, wolf, hare, and 

 rabbit, as well as in snakes, crocodiles, and fish ; and occasionally in man. In 

 their mature form, they inhabit the frontal sinuses of the hare, rabbit, and 

 horse. 



CLASS III. MYRIOPODA (CENTIPEDES AND 

 MILLEPEDES). 



THIS is the most worm-like class of the sub-kingdom Annulosa in the perfect 

 state of the animals included under it. The head is well differentiated from 

 the rest of the body, and is provided with one pair of 

 antennae, and three (more rarely, two) pairs of jaws. The 

 thorax and abdomen are not differentiated, except into 

 segments. They undergo a reversed and very imperfect 

 metamorphosis compared to that of insects, for whereas 

 insects begin with a worm-like body, sometimes provided 

 with as many as twenty-two legs, and end with only six, the 

 Myriopoda sometimes begin with only six legs, and continue 

 to increase both in number of joints and number of legs, 

 till they have reached their full growth, in which they are 

 generally long and worm-like. Hence they are called Myria- 

 poda or Myriopoda (either form of the word being equally 

 correct) ; and they are sub-divided into two principal orders, 

 tlie Chttopoda which are generally called centipedes or 

 at. size. hundred-feet ; and the Chilognatha, which are generally 

 called millepedes or thousand-feet. 



ORDER CHILOPODA (CENTIPEDES). 



The centipedes are carnivorous, and are provided with perforated foot- 

 jaws, connected with a poison-gland. The body and jaws are generally 

 rather flattened, and there is never more than a single pair of legs on each 

 segment. The head is divided into two regions, provided with two pairs of 

 maxillae, behind which spring the great foot- jaws. 



The tfcutigeridte are distinguished from the other families of CJiilopoda by 

 having the two pairs of mandibles united, and by the long antennae, 

 legs, and abdominal appendages, which has led to the common South European 

 species being called Scutiyera araneoides (Pall.), from its fancied resemblance 

 to a spider. It is about an inch long, the antennas being at least as long as 

 the body, and the last pair of legs twice as long ; the other legs are compara- 



