On the role of the connective tissue in the patterning of the chick limb musculature.

By modifying the temporal relationship between connective tissue and myogenic cell invasion during early limb bud development new evidence of the organizing role of the connective tissue was obtained.Muscle cell-deprived wing buds were allowed to grow up to stages 22 to 27 of Hamburger and Hamilton, when they received a transplant of quail myogenic cells (somitic mesoderm or wing premuscular mass) into the dorsal face of their presumptive upper arm. Muscular arrangement in forearm and hand was analyzed 4 days later. In 8 out of 14 of those cases which had received a graft of premuscular mass before stage 25 of Hamburger and Hamilton, muscle development took place distally to the graft-site in accordance with the wing segment.