A treatise on zoology . et more numerous than thevertebrae (Fig. 46, B). All these facts seem to uphold the secondhypothesis, according to which the neural spines and the fin-radials represent the proximal and distal regions of an originally. Fig. 46. Diagi-ams showing the modifications of caudal fins, and tlie relations of the endoskeletalradials of median fins to the axial skeleton. A, diphycercal type, with equal dorsal and ventrallobes (Dipnoi); B, heterocercal type (Selachii); C, modified diphycercal (Coelacanthini); D,heterocercal (Chondrostei); E, hoinocercal type (Teleostei); F, abbrev
A treatise on zoology . et more numerous than thevertebrae (Fig. 46, B). All these facts seem to uphold the secondhypothesis, according to which the neural spines and the fin-radials represent the proximal and distal regions of an originally. Fig. 46. Diagi-ams showing the modifications of caudal fins, and tlie relations of the endoskeletalradials of median fins to the axial skeleton. A, diphycercal type, with equal dorsal and ventrallobes (Dipnoi); B, heterocercal type (Selachii); C, modified diphycercal (Coelacanthini); D,heterocercal (Chondrostei); E, hoinocercal type (Teleostei); F, abbreviate heterocercal type(Amioidei). , anal fin ; , axial lobe ; , epichordal radial ; def, dorsal lobe partlyformed by epichordal lobe; , dorsal fin; c/, epichordal lobe; , haemal arch; hf,hypochordal lobe; liy, hyjjural arch ; , neural arch ; ttt, notochord; r, radial. Theendoskeleton is black. continuous skeletal rod with several joints, ^^e should not, then,believe that the fin-skeleton has developed independently at thebase of the fin itself, and has grown iuAvards centripetally; but,on the contrary,. Ave should consider the Avide separation of theradials from the vertebral column in some fish (Elasmobranchs) ass
Size: 1846px × 1354px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
