Figure 4.

(A) Hypothetical schematic representation of the relative expression domains of hyp 1, budhead, and Cn-ems in the hydrozoan head, based on descriptions and figures presented independently in the literature for each gene. See text for details. (B) Schematic transverse section of the hypostome at the level indicated by the arrows in A. The inter-taeniolae spaces (it) appear when the polyp feeds (to allow food passage) and are drawn for demonstrative purposes only. (C) Transmission electron microscopy enlargement of the rectangular section indicated in B; (Bar = 3 μm.)