The juvenile nerves follow the same pattern of development, with the formation of the ring nerve, radial nerves, and nerves associated with the tube feet and buccal podia (Hirokawa et al., 2008; Dupont et al., 2009; this study) after the development of the water vascular system (MacBride, 1907; Narasimhamurti, 1933; Olsen, 1942).
5H) and with additional parts of the water vascular system (ring canal, radial canals, stone canal, and pore canal).
Substantial numbers were also found within the water vascular system, especially in the madreporite and stone canal [ILLUSTRATION FOR FIGURES 1-12 OMITTED].
The water vascular system is connected indirectly to the perivisceral coelom through an opening between the upper end of the stone canal and the adjacent axial sinus [ILLUSTRATION FOR FIGURE 13 OMITTED] (cf., Jangoux and Schaltin, 1977; Bachmann and Goldschmid, 1978).