annulosa: myriapoda. 247 



European genera of this order. The ordinary Centipedes of 

 this country are perfectly harmless, but those of tropical re- 

 gions sometimes attain a length of a foot, or more, and these 

 are capable of inflicting very severe, and even dangerous, bites. 

 Order II. Chilognatha. — This order comprises the vege- 

 table-eating Millipedes {lulidm) and the Gallyworms (Polydes- 

 mus). ■ The order is characterised by the great number of legs, 

 — each segment, except the six or seven anterior ones, bearing 

 two pairs ; by the composition of the antenns out of six or 

 seven joints ; and by the structure of the masticating organs, 

 which consist of a pair of mandibles without palps, covered by 

 a lower lip, composed of the confluent maxillse. The genera- 

 tive apertures are placed in the anterior portion of the body. 



Fig. 82.— Millipede (/!(/!«). 



In the common Millipede {lulus) the body is composed of 

 from forty to fifty segments, each of which bears two pairs of 

 minute, thread-like legs. The luli of this country are of small 

 size, but an American .species attains a length of more than 

 half a foot. 



Order III. Pauropoda. — In this order is only an extra- 

 ordinary little Myriapod, described by Sir John Lubbock 

 under the name ol Pauropus. The body is only one-twentieth 

 of an inch in length, and consists of ten somites, furnished with 

 scattered setae. There are only nine pairs of legs, of which 

 one pair is carried by the 3d segment, whilst the 4th, Sth, 6th, 

 and 7th segments carry each two pairs of legs, and may there- 

 fore be regarded as really double. The head is composed of 

 two segments, and is not provided with jaw-feet. The antennse 

 are five-jointed, bifid, with three long multi-articulate appen- 

 dages. The body is white and colourless, and there are no 

 traches, so that respiration must be effected entirely by the 

 skin. Pauropus is found amongst decaying leaves in damp 

 situations, and species have been described both from Britain 

 and America. It is separated from the Chilopoda by its small 

 number of legs, the absence of foot-jaws, and the composition 

 of the antennae out of no more than five joints. 



Distribution of Myriapoda in Time. — About twenty 

 species of Myriapoda are known as fossils, the oldest example 

 of the order having been found in the Carboniferous epoch. 



