. The Cambridge natural history. Zoology. TELSON OF PHYLLOPODA 23 the telson carries two flattened backwardly - directed plates, one on eacli side of the anus, the margins of each plate being fringed with plumose setae. In Artemia the anal plates are rarely as large as in Branchiptis, and never have their margins completely fringed with setae; in A. salina from Western Europe, and in A. fertilis (Fig. 4, A) from the Great Salt Lake of Utah, there is a variable number of setae round the apical lialf of each lobe, but in specimens of A. salina from Western Siberia the number of setae may be very
. The Cambridge natural history. Zoology. TELSON OF PHYLLOPODA 23 the telson carries two flattened backwardly - directed plates, one on eacli side of the anus, the margins of each plate being fringed with plumose setae. In Artemia the anal plates are rarely as large as in Branchiptis, and never have their margins completely fringed with setae; in A. salina from Western Europe, and in A. fertilis (Fig. 4, A) from the Great Salt Lake of Utah, there is a variable number of setae round the apical lialf of each lobe, but in specimens of A. salina from Western Siberia the number of setae may be very small, or they may be absent; in the closely allied A. urmiana from Persia the anal lobes are well developed in the male, each lobe bearing a. Flo. 4.—A, Ventral view of the anal region in Artemia fertilis, from the Great Salt L;ike ; B, ventral view of the telson and neitihlwuring parts of Lepidurws productus ; C, side view of the telson and left anal lolte of listheria (sp. ?). single; terminal hair, Init they are altogether absent in the female. Schmankewitch and Bateson have shown that there is a certain relation l)etween tlie salinity of the water in which Artemia salina occurs and the condition of the anal lobes, specimens from denser waters having on tiie whole fewer setae ; tlie relation is, liowever, evidently very complex, and furtlier evidence is wanted l)efore any more definite statements can be made. In the Apodidae tlie anal lobes have the form of two jointed cirri, often of considerable length; in Ajms the anus is tenniiud, but in Lepidurus (Fig. 4, 13) the dorsal part of the telson is prolonged l^ackwards, so as to form a plate, on the ventral face of which the anus opens, much as in the Malacostraca. In the Limnadiidae (Fig. 4, C) the telson is laterally com-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble
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