External morphology and craniofacial cartilage organization in wild-type 5 day post-fertilization (dpf) Danio rerio larvae. A, lateral view of a fixed zebrafish larva. B, ventral view of larval head skeleton. C, lateral view of same fish imaged in B. D, flat-mount of viscerocranial skeleton after removal of the neurocranium (10X magnification). E, flat-mount of neurocranium (10X magnification). cb, ceratobranchials; ch, ceratohyal; ep, ethmoid plate; hs, hyosymplectic; m, Meckel’s; pc, parachordals; pq, palatoquadrate; and t, trabecula. Bone and pharyngeal teeth (arrowheads) and otic vesicles (arrow) are also shown. Scale bars are 500μm.