. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Davaineid Cestode from a Wallaby. 607 trunk is situated about midway between the ventral excre- tory vessel and the inner marg-iu of the cirrus-pouch ; it may, however, approach and lie close to the excretory vessel. On the aporal side the nerve-trunk lies in close proximity to the ventral excretory vessel. The course of the nerves in the head region was not followed. (d) Genital Organs (figs. 3 and 4).—Each mature seg- ment possesses one complete set of male and female genita
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Davaineid Cestode from a Wallaby. 607 trunk is situated about midway between the ventral excre- tory vessel and the inner marg-iu of the cirrus-pouch ; it may, however, approach and lie close to the excretory vessel. On the aporal side the nerve-trunk lies in close proximity to the ventral excretory vessel. The course of the nerves in the head region was not followed. (d) Genital Organs (figs. 3 and 4).—Each mature seg- ment possesses one complete set of male and female genitalia, witli their genital pores close together and unilateral in position. These pores are in the anterior third of the segment, and are situated on a slight eminence. Each eminence is over- hung by the projecting posterior angle of the segment preceding. The genital rudiments of the ovaries are the first to appear. Mature segments, slightly flattened. (Magnificatioii about 40.) iN'. = nerve-cord; Oy. = ovary; /S''. = shell-gland; r. = testes; vas deferens; F'.i!'.C'. = ventral excretory gland; F.(?.=yolk- gland. about 8 mm. from the anterior end ; some mms. further down the vagina begins to develop, to be soon followed by the vas deferens. The rudiments of the testes appear very much later, their first indications being at about 40 mm. from the anterior end. Mature segments ai*e found about 5 mm. further down. All the genitalia are confined to the central third of the parenchyma, being bound dorsally and ventrally by the thin sheet of transverse muscles and laterally by the ventral excretory canals. The male organs consist of about 50 rounded testes, about 65 /x in diameter, arranged in two groups separated by the ovary. The larger group, which consists of about three- fourths of the number of testes, is situated aporally. The testes do not pass laterally over the ventral excretory Please note that these images are extracted from scanned page images that may
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