230 



enelo 



VRIITEIMiATE AXI.MALS. 



^aeluse any tlinr.-icic c;i\'itv, or jn'otect tlie i>il;.hiis whicli iire usually 

 coiitaiiR-d in tlic clifxt— iiaiDely, the lieai t aud breathing-organs. 

 The aiitei'ior or lower ends of tile rilis .if tislie.-i are free, or are 

 rarely united to hard pindnctions of Die integnuieiit ; but there is 

 ne\'er any brt.'ast]>(.)ne or ntrnnnn jiruperly so called. 



Tlie only I'euiaiinng liones of tlie trunk jirojier lire the so-cdled 

 ^' ititerspiiions bones" (tig. Kio, / /), These are a series of jiointed 

 d.igger-like bone.s, endiedded in the middle line of the body, bet^veeu 

 the great lateral muscles \yhieh form the greater ]iart of the body of 

 a tish. Tlie inner ends or points of the interspinous bones are at- 

 tached by ligament to the sjiinous jirocesses of the vertebrie, and at 

 their outei' ends they su]i|iort the framework (riiys) of the so-called 



Fi,;^. lerj.— Sk.'lctoii or tin: coniinnu I'ncli (/'.vr.i l> ,iri,illlis). p Pectural liii ; i- One of 

 llic vciitnil liii^ ; ./ Anal liiL, .sii]i]inil,.(l ii]„,ii inl ris]iiiinuy Ik.ims (,) ; i- Caliilal liii ; 



d l''iist ,l.,rsal Ilii ; W ,s ,ihI dorsal liri, l.oth sn|i|.nHnl ii|i.iii ind rs|.iiMiiiK Imiirs ; 



( (■ !ii1rrs]iiiioiis Itniiis ; , liihs ; ,v Spinous liroccssrs of \aairlii;r ; // llaanal piii- 

 (Tssrs of v.Tlvliia'. 



"' medinn " fins. As a rule tliere is only one interspinous Ixme to 

 e;irli \ertebra, but in the Flat-fishes (Sole, Turbot, &c.) there are two. 

 The liiulis of fislies m.-iy be wholly wanting, or one ]iaii' may be^ 

 abseid, but in im c-ise is the nuinbei- greater tlian the regular Verte- 

 br:ite (y|ie — ii.'iuiely, {wn pairs. When deyelo|ied, ho\\-ever, the 

 limbs of fishes are vci-y ditferent from those of other Vertebrates, 

 consisting of ex|i;insions of the iidcgnment, f\irnished ^^■ith bony 

 or gristly su]iports oi- i-.iy.s, .and thus constituting \\h;d. are e.nllcd 

 '■fins'' (fig. km;). The p.aii' of lindis wliicli ci.rrespond to the arms 

 i>f ni.-iu .-lud to the fore-lindis of othei- Vertebrates arc termed the 

 jii-i'liii-dl tins, .-ind they are att;i(dicd to a boTiy .arch wliich is attached 

 eith.'r I., the b;M-k of th.' the skull or t.> the spin:il clnnin (fig. Ki.'i, 

 y, niid I dr., y.\ '1'Ih-. hiud-liinbs in fishes are knoA^ai as the rci/tnil 



