144 



INVERTEHRATE ANIMALS. 



of the thoracic legs. There i.s a well-developed abdcjmen, and there 

 are seven pairs of thoracic legs, directed jjartly forwards and partly 

 backwards, ({cjod e-xanijiles are tlie Sand-hojipers {Talitriis, fig. 

 il-J, A) and the " Fre.sh-water 81irini)is" ((rriwwrtrti.f, fie;. !)2, B). 



The Saiid-ho|i]ieis ami (niiiiinnri swim on their side when i:i the 

 water, .-ind the fnrnicr leap with Ljreat activity on land. 



Fig. ■.)-2.-Anii.lii|'"'l'i. A, 'falilni.i h«iisti', IIm- " Saiid-lic.i.iwr," fiil.'Ligtd. B, (inmjmnis 

 h,f ifsh:, (.iiliiigi-.l uljDUt li.in- liiiifs. (Alti']' Sin-nce Bate and Westwood.) 



Nearly rclateil to the Anijihijiods are a number of little L'nis- 

 t.-iccaiis (Ldiiiodijiodii), in which the abdomen is quite rvulimentary. 

 8oi]ie of these (f.,'/., the Whale-lice) are ]:arasitic in their habits, 

 and all inhabit the sea. 



Ol'.DER MeIIOSToJI.VT.V. 



lii this order are only the living King-crabs (I^imnliiK), and .some 

 large e.xtinct forms nearly .allied to them. They are all distingnished 

 by the fact tl^it the ap])endages Avhich are jilaccd I'oiind the mouth 

 art liy llii-ii- bases as j.aws, bnt have their extremities developed into 

 s\v)niiiiiiig-|ia(|rUes, walking-feet, (jr nij>ping-cla.ws. 



