Ori"in of muscles, [478]

Ori"in of musculature, branchial, [170]

Ori"in of muscul"ture, somatic trunk, [406]

Ori"in of nervous system, central, [480]

Ori"in of notochord, [434]

Ori"in of segmental excretory organs, [389]

Ori"in of skeleton of vertebrates, [119]

Ori"in of vertebrates, [9], [36], [351], [433], [493]

Ostracodermata, [326], [343]

Osteostraci, [29], [75], [275], [326], [343]