552 



TELEOSTEf 



However, a ventral process of the coracoid present occasionally 

 in the adult (Fig. 324), but more frequently in the early stages 

 of development, has been supposed to represent the tin axis 

 (Swinnerton [432], Halle r [1 9-4]). But in some few cases 

 there is a greater number of radials {Anguilla, Malapterurus (Fig. 

 335), Muraenolepis). Whether this larger number really represents 

 the survival of a more primitive condition, as Sagemehl supposed, 

 it is difficult to say ; on the whole, it seems more probable that it 

 does not. Vestiges remain of the pelvic radials only in lower 



,-nac. 



-bd 



Pig. 336. 



A, Left-side view of two trunk vertebrae of Esox lucius, I.. I>, vertical median section of the 

 same. D, C, and E, Thynnus vulgaris, Cuv. C, anterior trunk region; D, posterior trunk 

 region; K, caudal region, bd, basiventral (haemal arch); bd.c, basidorsal cartilage; bv.e, 

 basiventral cartilage ; c, centrum ; d.r, dorsal rib (epipleural) ; epn, epineural ; li, longitudinal 

 ligament ; n.a, basidorsal (neural arch) ; n.a.c, its cartilage (interdorsal?); n.a.l, left neural arch ; 

 n.c, neural canal; nt, notochord ; p.r, pleural rib; prz, anterior articulating process; ptz, 

 posterior articulating process. 



forms. The pelvic girdle consists of two bones sometimes united 

 in front by cartilage (Gadus, p. 276), sometimes expanding behind 

 into large plates spreading towards the middle line (Siluroids, etc., 

 Fig. 30 5). 



The vertebral centra show no signs of compound structure. Ah 

 a rule, they are more or less solid and biconcave (Figs. 336, 337), 

 the notochord in living genera being usually constricted to a mere 

 fibrous thread (Goette [167], Grassi [182], Scheel [385]). The 

 centra are generally, but not always, co-ossified with the arches and 

 these with the spines. Intervertebral articulations are formed by 



