Figure 1. Lynceus simiaefacies. A in The feeding mechanisms of Lynceus (Crustacea: Branchiopoda: Laevicaudata), with special reference to L. simiaefacies Harding

Figure 1. Lynceus simiaefacies. A, bisected female, ventral side uppermost, seen from the midline after removal of the labrum which obscures part of trunk limb 1, showing the median face of the 12 left trunk limbs. Limbs 11 and 12 are very small. The trunk limbs lie more or less as at the end of promotion. Of particular note is that, except on the distal scraper-bearing endites, and at the extreme posterior end, the median face of the limbs is covered by a screen of posteriorly and somewhat dorsally directed setae. The gnathobases of the seven anterior limbs are conspicuous: more posterior gnathobases less easily seen. Note how the cuticle-lined food groove, here torn away over much of its length, widens greatly into a 'basin' in the vicinity of the first three gnathobases. Trunk limb 12, detached from the right hand series, is present at bottom right. Except that the gnathobase lies proximally its orientation bears no relation to that in life. Scale bar 500 Mm. B, distal elements of gnathobases 4–6, seen within the confines of the food groove (FG). Note the stout denticulated spines that sweep food material forward (here to the left), the smooth curved spines (SCS) that are directed posteriorly, and the long, posteriorly directed, soft retaining setae (RS), of which the anteriormost extends posteriorly across the two gnathobases posterior to it. The tips of many screening setae, of which those seen anteriorly are clogged with screened out detritus, are readily seen. Note how the cuticle that lines the food groove reflects segmentation. The segments, of which parts of four are represented, increase in length from posterior to anterior. Scale bar 100 Mm. All subsequent figures refer to L. simiaefacies.