In -2 



INVEHTI'.BRATE ANIMALS. 



juices of their prey. Tlie intestinal canal is usually short and 

 straight, and is eonliuued without cnuvolutions to the aperture of 

 tlie anus. S.-divar;,' glands are als., jiresent, as well as randfied tubes 

 ("Mal[.ighian tulies"; which arc lielieved to act as kidneys. 



The circulation is niaintainril l)y njeans of a dorsal heart, which 

 is situated above the aliiueid,ary canal. The typical A lUc/mida 



-. lul.— lV.Ii|i:ili.i. A, .^lun-jnu „/,■,-, \i.AV,.l (Vniu a1 1 ivc, ;i ii.l Si niirwliiit rr.IlTfcd ill 

 sizr. Ji, rc.iil jifirl i(ui i<[ llic licail uf tlM' suiiL,-, \ H^wi-Q IVnui alicvi', and ciilurged. 

 <:, l:i,lh,f^ Kn,-hii, Willi Ilic Icniiiiial si.giiiri.ls ali.l tlir fiuLs of lliL- .■lpIX•lL.Ul^'^■s wi 

 .nil: »i.[u oiiiill.'-l. ,« Maxillary Jialiii (brliiial Unsc alv tl.f four pair of aliibllla- 

 tovy Ir-s) ; .■ I'lirli.-rr-,.' ; ( Triscn; " Lalcial oialli ; ,/ CiMitral, l.irger ocelli; ff 

 (111! iviilar |ilalc. cnvriiii;^ lli.. cjiriiiii- .i|- llir ]-.|,i,«liu--ti\c oVKiuis: r One of the 

 ■' .(.iiil.s; ■■ N ihic or till- (i]iciiili-s ii.lo till- [.illUHaiary sacs. (C is after rrof, E.ny 

 Limlicslcr.) 



■ealhe air ilircctly, and the function of respiration is ]icrfornicd by 

 le o'cncral siiL'face of thi^ body ('as in the lowest members of the 

 iiss), or liy branclied air-tidu's termed " tracliea'," or by distinct 

 iliiiotiaiy cha.nibe,i-s or sacs, or, lastly, b\' a, combinati^in of traehete 

 ilh pnliiioiiaiy sacs. The tiaclie;'' are essentially similar in stnic- 



