Fig. 3. Ventral body wall myoblasts appear to migrate as mesenchymal cells. (A) lbx1-expressing myoblasts of a stage 37/38 tadpole emerge at the somite cleft (arrows, most posterior somite with emerging myoblasts shown). (B) Another hypaxial myoblast-specific marker, tbx3, can be seen expressed in cells migrating out of the somite clefts in a stage 31 tadpole (arrows). Myotomes in A and B are labeled with 12/101 (brown). (C,D) lbx1 expression is found in long-range type hypaxial myoblasts. lbx1 expression in the geniohyoideus can be seen in a ventral view of a stage 42 tadpole (C, arrowheads), which co-localizes with 12/101 (D). (E,F) lbx1 is also found in the migrating muscles of the hindlimb of a stage 53 tadpole (E, arrows), similar to pax3 expression at the same stage (F, arrows) (limbs are shown from a lateral view, distal end towards the left).