358 



ZOOLOGY. 



three pairs of feet, and in this and other respects resembles 

 Podura. A second form, Eurypauropus, of Ryder, has six 

 segments, with feet wholly concealed from 

 above by the expanded segments. 



Order 3. (Jliilopoda. This group is rep- 

 resented by the centipede and Lithobius, 

 in which the body is flattened, the sternal 

 region being well developed. In Geophilus 

 (Fig. 308, G. Upuncticeps Wood) and allies 

 there are from thirty to two hundred seg- 

 ments. Our most common form is Litlio- 

 Mus Americanus Newport, found under 

 logs, etc. The centipede (Scolopendra 

 Jieros Girard) is very poisonous, the poison- 

 sac being lodged in the two large fangs or 

 first pair of legs. 8. gigantea Linn., of 

 the East Indies, is nine inches long. In 

 Cermatia the body is short, with compound 

 eyes in the head and remarkably long 

 slender legs. 0. forceps Rafinesque, of the 

 Middle and Southern States, is said to be 

 poisonous. 



An aberrant, generalized form is Scolo- 

 pendrella, in which the head and antennae are like those of 

 Campodea, a Thysanurous insect ; this is therefore a con- 

 necting link between the Myriopods and Hexapods. 



Sub-class 3. Arachnida. The bodies of spiders and scor- 

 pions, etc., are divided into two 

 regions, a head-thorax and abdomen, 

 the head being closely united with 

 the thorax. There are no antennae, 

 only a pair of mandibles and a pair 

 of maxillae, with four pairs of legs. 

 There are never any compound eyes. 

 The young are usually like the adult, 

 except in the mites, in which there 

 is a slight metamorphosis. In all 



Fig. 3QQ.Pauropus 

 Lvbbockii. Much en- 

 larged. Fig. 310 en- 

 larged view of head 

 ana antennse and first 

 pair of feet. 



Fig. 310. Head of Paurojws 

 Lubbockii. Much enlarged. 



Arachnida there is a liver, this organ not being present in 

 the winged insects. 



