File:Bulletin (1909) (20412978832).jpg

Title: Bulletin
Identifier: bulletin69smit (find matches)
Year: 1909 (1900s)
Authors: Smithsonian Institution; United States. Dept. of the Interior; United States National Museum
Subjects: Science
Publisher: Washington, Smithsonian Institution Press, (etc. ); for sale by the Supt. of Docs. , U. S. Govt Print. Off
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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Text Appearing Before Image:
With the exception of the cirrus pouch and the distal portion of the vagina, the reproductive organs are all contained in the medullary portion of the segment, as the portion within the inner longitudinal muscle layer may be termed. The vas deferens and vagina pass between the dorsal and ventral ex- cretory canals and dorsal of the lateral longitudinal nerve. Blale reproductive organs.—The testicles (fig. 3, t.) are of the usual oval shape, elongated dorso-ven- trall)^, measuring 60 to 120ju, in diam- eter, in number about 24. They are located in the lateral and posterior portions of the segment, inside of the inner layer of longitudinal muscles, extending forward to the anterior border of the segment on the dextral side. On the sinistral side of the segment the testicles do not extend so far forward, the an- terior third of the segment on this side being occupied by the vas deferens and seminal receptacle. In segments in which the female glands are at the height of their development the testicles in the middle third of the segment are IQo. Fig. 2.—Davainea ehynchota: Hooks. (a) Large hook from EOSTELLUM. (&) SMALL HOOK FROM EOSTELLUM. (C) HOOK FROM SUCKER. V. ,def. sem. recept. / d»ex.—K-
Text Appearing After Image:
lOQtt. Pig. 3.—Davainea rhynchota : Sexually mature segment, horizontal section, e. p.. Cirrus pouch, d. ex.. Dorsal excretory vessel, ov.. Ovary, sem. recept.. Seminal receptacle, t.. Testicles, v. def., Vas defeeens. y. g.. Yolk gland. crowded toward the sides and are then disposed in two groups, one in each lateral third of the medullary portion of the segment. In a segm-cnt containing 22 testicles, 9 were located on the left-hand (pore) side of the segment and 13 on the right-hand side. The vasa efferentia unite near the middle of the segment, toward the dorsal

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