資料來源 : Webster's Revised Unabridged Dictionary (1913)

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}.

   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}.