Protovertebrae

Protovertebra Pro`to*ver"te*bra, n.; pl. {Protovertebr[ae]} . [Proto- + vertebra.] (Anat.) One of the primitive masses, or segments, into which the mesoblast of the vertebrate embryo breaks up on either side of the anterior part of the notochord; a mesoblastic, or protovertebral, somite. See Illust. of {Ectoderm}. [1913 Webster]

Note: The protovertebr[ae] were long regarded as rudiments of the permanent vertebr[ae], but they are now known to give rise to the dorsal muscles and other structures as well as the vertebral column. See {Myotome}. [1913 Webster]