. A text-book of invertebrate morphology. Invertebrates. TYPE M0LLU80A. 319 large pyriform structure, whicli tapers somewhat to form a vagina opening to the exterior and receives a duct from the receptaculum seminis. The vas deferens {vd) shortly after its separation from the hermaphrodite duct dilates into a glandular structure, the prostate gland, from which the nar- row duct passes onward to terminate in an enlarged penis- sheath (jpe) which contains the muscular protrusible penis and opens to the exterior quite independent of the opening of the vagina. In the majority of the Stylommatophor
. A text-book of invertebrate morphology. Invertebrates. TYPE M0LLU80A. 319 large pyriform structure, whicli tapers somewhat to form a vagina opening to the exterior and receives a duct from the receptaculum seminis. The vas deferens {vd) shortly after its separation from the hermaphrodite duct dilates into a glandular structure, the prostate gland, from which the nar- row duct passes onward to terminate in an enlarged penis- sheath (jpe) which contains the muscular protrusible penis and opens to the exterior quite independent of the opening of the vagina. In the majority of the Stylommatophora (Fig. 143), however, the two ducts open into a common atrium so that only one genital orifice occurs, as in some of the Opistho- branchs (see p. 312). Other- wise the arrangement is simi- lar to what has been de- scribed for the Basommato- phora, except that in some forms, as Helix, one or two additional accessory struc- tures are added. Thus the atrium has communicating with it a sac which contains a sharp calcareous rod, the "dart," which serves as a stimulus during copulation, being plunged into the body of the other party to the act;. Fia. 143.—Repboductivb Oeganb of Limax maximus (after Simroth). al = albuminipaious gland. hd = hermaphrodite duct. !ig = hermaphrodite gland. li = ligament. od = oviduct. pe = penis-sheath. rs = receptaculum seminis. ut = uterus. lid = vas deferens. w = vesicula seminalis. and again just at the point where the vas deferens opens into the penis it has communicating with it an elongated tubular structure, the "flagellum," which perhaps furnishes the material of which the capsule of the spermatophores is composed. Development and Affinities of the Oasteropods.—The devel- opment of the Gasteropods is made interesting on account of. 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
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
