354 



TELEOSTEI 



ac 



Pig. 338. 



Transverse section of the vertebral column in the trunk of a very young Trout (Salmo), 

 enlarged. a.b, dorsal wall of air-bladder; a.e, abdominal coelom; bd, basidorsal cartilage; 

 bv, basiventral cartilage; c, posterior cardinal vein; el, elastica externa; f.s, librous sheath 

 .surrounding notochord ; r/.r, genital ridge ; It, dorsal longitudinal ligament : m.d, mesonephric 

 duet ; n.c, nerve-chord ; r, rib : si, skeletogenous tissue. 



A. B. 



Caudal vertebrae of Thynnus vulgaris (Cav. and Val.). A, right-side view; B, left-side 

 view of the same cut in half, a.v, anterior ventral process ; «.-, anterior ' zygapophysis ' ; r, 

 eeiitrum ; h.a, haemal arch; n.a, neural arch; p.v, posterior ventral process ; p.z, posterior 



' zygapophysis ' ; r place of attachment of rib. 



