Km. 55. PECTORAL ARCH OF VARIOUS AMPHIBIANS. From the ventral side. 

 A Urodele (diagrammatic) ; B Axolotl (Amblystoma) ; C Bomlnnnin,- 

 iy news ; U, J'nnn ewii/cnta. 



C, coracoirl ; Cl, procoracoid ; C7 1 (Cl in U), clavicle ; EC, Co 1 , epicoracoid ; 

 Ep, omostermun ; Fe, fenestra between procoracoid and coracoid bars ; /\n, 

 cartilaginous xiphisternum ; t, Pf, O, glenoid cavity for the humerus ; 

 S, scapula ; SS, supraacapula ; St, Sf l , sternum. *, j (in B) indicate nerve- 

 apertures. 



