. Elements of comparative anatomy. Anatomy, Comparative. Fig. 156 or seminal - an organ ovipositor, Phalangium Vas Generative organs A Male organs. t deferens, p Penis, to Retractors of penis. gi Appended glands (after Krohn). B Female organs, o Ovary. it Uterus, op Ovipositor. to Retractors of ovipositor. penis. The circular form of germinal gland is still retained, in its completeness, in many of the Acarina. In the female apparatus the greater part of the ring is converted into the efferent organ, owing to the limitation of the ova-producing part to a small division of it. This is
. Elements of comparative anatomy. Anatomy, Comparative. Fig. 156 or seminal - an organ ovipositor, Phalangium Vas Generative organs A Male organs. t deferens, p Penis, to Retractors of penis. gi Appended glands (after Krohn). B Female organs, o Ovary. it Uterus, op Ovipositor. to Retractors of ovipositor. penis. The circular form of germinal gland is still retained, in its completeness, in many of the Acarina. In the female apparatus the greater part of the ring is converted into the efferent organ, owing to the limitation of the ova-producing part to a small division of it. This is most marked in Pentastomum, where the ovary is attached to a circular canal. The ovary is here differentiated from the canal. The part of the ring, which forms the efferent ducts and passes into the single portion, is often widened out into a uterus; or the uterus is formed by the unpaired portion alone. This is the casein Pentas- tomum, the uterus of which forms a coiled canal of some length. The unpaired portion of the efferent duct is generally much shortened in the male, and the two parts of the rings connected with it are widened out into seminal vesicles. Appended glands are connected with the unpaired portion in both sexes. The great differences in the distribution of the functions of parts of this canal lead to the separa- tion of the ring into two genital tubes, the middle of the germ- producing portion of the ring becoming sterile. The two halves of the ring are then distributed to the sides, although in some cases they are still connected by a canal, or by indifferent tissue; this gives rise to organs which are only united at their orifices, or along an unpaired portion connected with them (Ixodes). The hermaphrodite generative organs of the Tardigrada are altogether unlike these arrangements. They consist of an unpaired ovary and two testes which lie beside the enteron : their efferent ducts pass into a receptaculum seminis, and open, generally provided with special
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectanatomycomparative
