File:Bulletin (1909) (19800665613).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:
16 BULLETIN 69, UNITED STATES NATIONAL MUSEUM, The suckers are oval, 115 to 135/^ wide by 160/x long, armed with numerous hooklets (fig. Qa) 10/* and less in length, arranged in diagonal rows on the border of the suckers, 16 to 18 in each row. The neck is of variable length up to 400/x,, and measures in width from 200 to 300/x. The segments are similar in shape to those of Davainea rhynchota and increase gradually in size toward the posterior end of the stro- bila. In a strobila 45 mm. long the number of segments was ap- proximately 175, of which the last 17 contained egg capsules. A segment (No. 130) in the middle of the strobila measured 320/* in length by 880/* in width, and a segment at the end of the strobila measured 650/* in length by 1.6 mm. in breadth. In some cases the gravid segments are equal in length and breadth. v.ex. l.n.-/
Text Appearing After Image:
^vag. sem.' recept 200a. Fig. 7.—Davainea comitata : Sexually mature segment, eeconstuuction from sec- TioNSj ventral view. c. p., CiEEus POUCH, d. ex.. Dorsal excretory vessel. I. n.. Nerve cokd. ov.. Ovary, sem. recept., Seminal receptacle, t.. Testicles, vag., Vagina, v. dej., Vas deferens, v. ex.. Ventral excretory vessel, y. g.. Yolk gland. The genital pores are unilateral on the left-hand margin of the strobila, situated in abo.ut the middle of each segment. Internal anatomy. The nervous system, musculature, and excretory canals are ar- ranged as in Davainea rhynchota^ and the relative location of the reproductive organs is the same. Th ) vas deferens and vagina pass between the excretory canals and dorsal of the nerve cord, as in the other species. Male reproductive organs.—The testicles (fig. 7, t.) number from 30 to 35, arranged in a mass occupying the lateral and posterior por-

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