. The Cambridge natural history. Zoology. 26 CRUSTACEA BRANCHIOPODA coiled proboscis of a butterfly, and the triangular membrane folded like a fan beside it, so that much of the organ is concealed, and the general appearance of the head is that shown in Fig. 5. During copulation, the whole structure is widely extended. The males of Artemia (Fig. 7) have the second antenna two- jointed, the basal joint bearing an inner tubercle, the terminal joint being flattened and bluntly pointed, its outer margin provided \vith a membranous outgrowth. In A. fertilis the breadth of the second joint va
. The Cambridge natural history. Zoology. 26 CRUSTACEA BRANCHIOPODA coiled proboscis of a butterfly, and the triangular membrane folded like a fan beside it, so that much of the organ is concealed, and the general appearance of the head is that shown in Fig. 5. During copulation, the whole structure is widely extended. The males of Artemia (Fig. 7) have the second antenna two- jointed, the basal joint bearing an inner tubercle, the terminal joint being flattened and bluntly pointed, its outer margin provided \vith a membranous outgrowth. In A. fertilis the breadth of the second joint varies greatly, the narrower forms pre- senting a certain remote resemblance to Fk;. 7.—aliemia fertilis. Front view of the head of a BrcmchinectCL In the male, showing the large second antennae, ; n^ales of Polyarteviici ., first antennae. ^ the second antennae have a remarkable branched form not easily comparable with that found in other Branchipodidae. The cephalic jaws are fairly uniform throughout the order. The mandibles have an undivided molar surface, and no palp ; the first maxilla is very generally a triangular plate, with a setose biting edge; mandibles and maxillae are covered by the labrum. The second maxilla generally lies outside the chamber formed by the labrum, and is a simple oval plate, with or without a special process for the duct of the kidney. The thoracic limbs, in front of the genital segments, are not as a rule differentiated into anterior maxillipedes and posterior locomotive appendages, as in higher forms; we have seen, however, that all these limbs take part in the prehension of food, and except in the Limnadiidae they all assist in locomotion. One of the middle thoracic legs of Artemia (Fig. 8, Aj has a flattened stem, with seven processes on its inner, and two on its outer margin. The gnathobase (jjn) is large, and fringed with long plumose setae, each of which is jointed ; this is followed by four smaller " endites " (or processe
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
