Fig. 4

a. SEM image of detached abdominal uncini. b SEM image of the row of uncini. c SEM image showing the rostral portion of an uncinus in detail. d Micrograph showing the apical portion of an abdominal hooked chaeta. arrows mark the direction of the internal canals. e Schematic drawing of an abdominal uncinus, in scale. dotted line illustrates the refracting seam at merger of the chaetal socket and base, rr rostral rod, ar adrostral rod, r rostrum, t tooth, s socket