Fig. 4.

Food capture in Aglantha digitale. (A) Ciliary beating drives water past the extended tentacles (arrows) bringing them into contact with prey (a copepod). Tentacular contraction and flexion brings the prey to the margin while the manubrium points across to it with flared lips. (B) Peduncle (p) and manubrium (m) of an unfed animal at rest. (C) Lateral flexion (pointing) to a site where food is held by the tentacles. (D) Mechanism for gradation of manubrial muscle response with distance from the prey site (*). Each set of traces (a–c) represents a pair of F impulses (top) and the graded muscle responses (bottom) at each of the recording sites shown. The second F impulse travels more slowly than the first and summation becomes less effective as the action potentials become increasingly separated. See text for more details. A–C from Mackie et al. (Mackie et al., 2003); D adapted and redrawn from Mackie (Mackie, 1984).