Embryological development is followed over a period of ten weeks after hatching. The mode of formation of the components of the vertebral column is compared with that inClupea harengus, and is described in detail where differences are observed or additional information is available. Development appears essentially similar in the two species, although in general more rapid relative to length inC.pallasii. At hatching, myotome formation is complete and the ultimate vertebral number of an individual is presumably determined by that time. During ossification of the vertebral column, complex growth gradients from one or more centres are observed.