Development of the vertebral column and caudal skeleton of the red sea bream, Pagrus major, is described from laboratory-reared series and wild specimens.Cartilage formation in these structures takes place at about 4.5 mm TL and ossification starts at about 6.0mm TL.The sequence of cartilage formation and ossification in P.major is compared with other species already described.Accessory cartilages found in the caudal region are described in detail.The number and arrangement of these cartilages are almost constant.The laboratory-reared specimens are more variable than wild ones in number of bones, e.g.vertebrae.It is likely that there are some differences between these two stocks in size of larvae at the stage of the appearance of accessory cartilages.Laboratory-reared postlarvae have many abnormalities in neural and haemal arch cartilages, and this may be related to the malformation of the centrum at later stages.
