“…Baptista et al, 1990;Blair et al, 1990;Gan and Macagno, 1995;Becker et al, 1996;Lans et al, 1996;Johnson et al, 2000;Jellies et al, 2000). Moreover, using fluorescent probes, the leech's large and accessible neurons can be observed down to the level of the growth cone filopodia, in situ and across time, in the intact, living embryo (Wang and Macagno, 1997;Baker et al, 2000Baker et al, , 2003.…”