Mutant phenotypes in living larvae. Lateral views at 6 days. Arrows indicate branchial arches, P3-P7, which are reduced in all of these mutants. Arrowheads indicate the lower jaw. (A) wild type, wt. The jaw extends anterior to the eye and gill filaments of the branchial arches, lined with blood vessels, protrude ventral to the otic vesicle (ot). (B) lowts213. The jaw is shifted ventrally and some gill filaments remain. (C) flatf21c. Gills are severely reduced. (D) babtb210c. The head is severely reduced, the jaw does not extend and gills are absent. (E) sertk18c. The jaw is reduced, the mouth hangs open and gills are slightly reduced. (F) factu45b. Only gills are reduced. (G) tq235. All arches are absent and the mouth is displaced posteriorly. (H) daktw25. All arches are shorter and wider than normal and the jaw is displaced posteriorly. (I) boxtm70g. The jaw hangs slightly and gills are reduced.