. Bulletin of the British Museum (Natural History). TAENIA KREPKOGORSKI 185 size of those in the inner. Complete bundles in the inner layer contain about 38-42 fibres, while those in the outer layer have about 19-30 fibres which appear to be rather more closely packed. The bundles in both layers are weakly developed and very numerous. A single layer of circular muscle-fibres lies inside the longitudinal layers (fig. 2b). The ventral excretory vessels are much larger than the dorsal and are more laterally disposed. In cross-section the lumen of the ventral canal is about 0-15 mm in diameter, an
. Bulletin of the British Museum (Natural History). TAENIA KREPKOGORSKI 185 size of those in the inner. Complete bundles in the inner layer contain about 38-42 fibres, while those in the outer layer have about 19-30 fibres which appear to be rather more closely packed. The bundles in both layers are weakly developed and very numerous. A single layer of circular muscle-fibres lies inside the longitudinal layers (fig. 2b). The ventral excretory vessels are much larger than the dorsal and are more laterally disposed. In cross-section the lumen of the ventral canal is about 0-15 mm in diameter, and that of the dorsal canal about o-oi mm. The two ventral vessels are connected by a transverse canal lying near the posterior margin of the segment. No corresponding connection between the dorsal vessels has been made out either in whole preparations or in serial sections. The longitudinal nerve-cords lie close to the ventral canals and directly lateral to them. The genital pores alternate irregularly, and are situated at about the middle level of the segment margin. The genital ducts pass ventrally to the excretory canals and open into the base of a genital atrium, which is narrow and 0-2-0-25 mm deep. The cirrus-sac, as seen in transverse and horizontal sections, is more or less club shaped, usually reaching to the ventral excretory vessel and measuring 310 — 430 [xm by 70-90 | It contains an uncoiled tubular cirrus. An everted cirrus was not seen. A tightly coiled vas deferens leads into the cirrus-sac. The maximum number of testes counted in a single horizontal section was about 145, while an estimate of their number from an examination of whole mounts varies between 360 and 400. Each testis is globular, or nearly so, and measures 25-35 (xm in diameter. They are arranged in two lateral groups of roughly equal size, joined by a narrow band of testes disposed anteriorly to the ovary. The lateral fields do not meet behind the vitelline gland (fig. 2a). The ovary is dist
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Keywords: ., 1973, boo, bookauthorbritishmuseumnaturalhistory, bookcentury1900
