14 URODELA 



All the trunk -vertebrae, with the exception of tlie atlas, 

 carry ribs, at least vestiges thereof. Owing to the early dis- 

 appearance of the basiventral cartilages the capitular portions of 



the ribs are much reduced, and 



/^^-— ^^X^ are mostly represented by strands 



// \\ of connective tissue only. The 



( I ^""^ ) A -^^^^ develop therefore occasion- 



) ^^ ^ /aC' *lly ^t some distance from the 



>■• ..('3^V^^__X]II--^^5A^ vertebral column, and that por- 



//^^r^S^'^ \\ tio^ of the rib which in the 



// ^^' '^^- metamorphosed young newt looks 



// like the capitulum is to a great 



^ extent really its tuberculum. 



Fig. 2.— Transverse section tlirough a Witness the position of the ver- 

 truuk - vertebra of a larva of Sata- fpV,^„l m-fpr-Tr wliipli cHll inrli 

 nmndra maculosa, <in\^vg<ii. The right ^^DraX artery, WJllcn StUi mdl- 



side shows the actually existing state, cates the true foramen trans- 



while on the left side the rib and its • mi i i • c 



attachments are restored to their pro- versarium. The homologies of 



bable original condition. A, Verte- these parts are Still more ob- 

 bral artery within the true transverse j i, , i. r ^ j.-i i. 



canal ;&F, remnant of the basi-ventral SCUred by the lact that a new 



cartilage ; Ok, chorda dorsalis ; Sp.c, proCeSS grOWS OUt from the rib 



spinal caual ; , the false transverse i , • , , , 



canal. by which the latter gains a new 



support upon a knob of the 

 neural arch. Thus an additional foramen is formed, sometimes 

 confounded with the true transverse canal. The meaning which 

 underlies all these modifications is the broadening of the body, 

 the ribs shifting their originally more ventral support towards 

 the dorsal side. The whole process is intensified in the Anura ; 

 it is an initial stage of the notocentrous type of vertebrae. The 

 transverse ossified processes of the adult are often much longer 

 than the vestiges of the ribs themselves, and are somewhat com- 

 plicated structures. They are composed first of the rib-bearing 

 cartilaginous outgrowths of the neural arches ; secondly, of a broad 

 string of connective tissue which extends from the ventro-lateral 

 corner of the perichordal skeletogenous layer to the ribs. 



The shoulder-girdle is extremely simple. It remains almost 

 entirely cartilaginous, and the three constituent elements are not 

 separated by sutures. Ossification is restricted to the base of the 

 shaft of the scapula, and may extend thence over the glenoid 

 cavity. The coracoids are broad, loosely overlap each other, and 

 are " tenon and mortised " into the triangular or lozenge-shaped 



