ANATOMY OF VEETEBRATES. 



67 



between it and the litemapopliysis. A small cartilaginous appen- 

 dage is attached to some of the ribs. 



The lumbar vertebnB are those in which the diapophyses cease 

 to support moveable pleurapophyses, although they are elongated 

 by the coalesced rudiments of such, ib. e,f,fj, h, which are distinct 

 in tlie young Crocodile. The length and j)ersistent individuality 

 of more or fewer of these rudimcntal ribs determines the numljcr 

 of tlic dorsal and lumljar vertel5ra3 respectively, and exemjilifics 

 the purely artificial character of the distinction. The numl:)er of 

 verteljr;T3 Ijctween the skull and the sacrum is twenty-four. In 

 the skeleton of a Gavial, I have seen thirteen dorsal and two 

 lumbar; in that of a Crocodihis cutuphractus twelve dorsal and 

 three luml^ar ; in those of a Crocodilus acutus and AlUr/otor lucius, 

 eleven dorsal and four lumbar, fig. 57, which is the most com- 

 mon number. Cuvier assigns five lumbar vertebras to Croc. 



55 



riia.^vani of postcrioi- trimlc-vcrtclira;, Crocodile, cc. 



hiporcatus. But these varieties in the developement or coales- 

 cence of the stunted pleurapophysis are of no essential moment. 

 The coalescence of the rib with the diapophysis obliterates of 

 course the character of the ' costal articidar surfixce,' Avhicli we 

 have seen to be common to both dorsal and cervical ^-ertel^raj. 

 The lumbar zygapo2)hyses have their articular surfaces almost 

 horizontal, and the diapophyses, if not longer, have their antero- 

 posterior extent somewhat increased ; they are much depressed, 

 or flattened liorizontally. 



The sacral vertebrfc, fig. 57, S, are very distinctly marked by 

 the flatness of the coadapted ends of their centrums ; there are 

 never more than two such vertebrfe in the Crocodilia, recent or 

 extinct : in the first the anterior surface of the centrum is concave, 

 in the second the posterior surface ; the zygapophyses are not 

 obliterated in either of these sacral vertebras, so that the aspects of 



F 2 



