PLATE 4 
EXPLANATION OF FIGURES 
4 Stage 5. Dorsal aspect of lower jaw and hyobranchial apparatus, X 20. 
Membrane bones represented on right side. 
5 Stage 5. Lateral aspect of solid model (‘cast’) of cavity of otic capsule, 
x 40. Note that fenestrae appear as projecting plugs. 
6 Stage5. Posterolateral aspect of occipital region, X 40. 
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