although the posterior-vegetal blastomeres ( b4.1 pair ) of the 8-cell embryo have long been believed to be the sole precursors of larval muscle , recent studies using horseradish peroxidase to mark cell lineages have shown that small numbers of muscle cells originate from the anterior-vegetal ( a4.1 ) and posterior-animal ( b4.2 ) blastomeres of this stage .
C0026845
muscle
C0596981
muscle cells