Figure 4. Right trunk limb 6 in The feeding mechanisms of Lynceus (Crustacea: Branchiopoda: Laevicaudata), with special reference to L. simiaefacies Harding

Figure 4. Right trunk limb 6, as seen from the outside, to show its general form and musculature. Only part of the armature of endites 2 and 3 is shown to indicate the arrangement of the grid setae and some of the spines. Only the distal armature of endites 4 and 5 and the endopodite is visible from this side. Further rows of scrapers are located more proximally on the hidden margins of these elements, whose location is indicated by a dashed line in each case. Some of these spines are visible distally on the margin of endite 4, but are omitted to avoid confusion in that region. Likewise, only a few of the gnathobasic setae, of which there are two rows anteriorly, are shown. The delicate exopodite is stippled to show its distinctness from the corm. The long setae with which both its dorsal and its ventral lobes are provided are omitted. The long, cylindrical epipodite is also stippled. Scale bar 250 Mm. EA, EB, EC, assistant extrinsic remotor muscles; ED, probable adjustor muscles; EP, extrinsic promoter muscles; ER, extrinsic remoter muscles; E2–E5, endites 2–5; En, endopodite; Ep, epipodite; Ex, exopodite; F, fibrous endoskeleton of gnathobase; GA, 'abductor' muscle of gnathobase; Gn, gnathobase; GS, grid setae; RF, region of flexibility; RS, retaining seta of gnathobase; TA, transverse apodeme; 1–14, intrinsic muscles (for probable roles see text); a–e, muscles of exopodite.