File:Text-book of comparative anatomy (1898) (14592707428).jpg

Identifier: textbookofcompar01lang (find matches)
Title: Text-book of comparative anatomy
Year: 1898 (1890s)
Authors: Lang, Arnold, 1855-1914 Bernard, Henry Meyners Bernard, Matilda Haeckel, Ernst Heinrich Philipp August, 1834-1919
Subjects: Anatomy, Comparative
Publisher: London, New York, Macmillan and Co.
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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Organisation of Myzostorua cirriferum, after v. Graft. To the left the parapodia(p), the suckers (sn), and the male genital apparatus are represented. To the right the entericbranches (</«) and ovaries (o). c, Cirri; php, pharyngeal tentacles ; ph, pharynx; pht, pharyngealpouch ; ill, stomach (mid-gut); ed, hind-gut; «, uterus ; ivo, female genital aperture, which entersthe cloaca; Mo, aperture of cloaca; pm, muscles for moving the parapodia; mo, male genitalaperture ; s6, sperm vesicle; vd, vas deferens ; li, testes ; p, parapodia with hooks and supportingrod. the Platodes, It is, however, probable that this is more a caseof analogy than of homology. In the sexually mature animalsthe parenchyma is filled with numerous egg cells which lie in VERMESâGENITAL OR( L 1 .V,S 263 masses between the branches of the intestine, especially on the dorsalside. These masses of eggs are regarded as ovaries. It is, however,possible that they consist of eggs which have left the real ovaria. da
Text Appearing After Image:
genital FIG. 176.âSection through Myzostoma, after v. Graff, ov, Ovaries ; da, intestinal branches ;!t, uterus; dm,, dorso-ventral muscle fibres; sn, suckers; h, testes ; qm, transverse muscles ; Im,ventral gaiiglionic masses ; pa, parenchyma ; md, intestine. The origin and places of formation of the eggs are not known with anycertainty. The ripe eggs pass into a spacious uterus which lies on thedorsal side of the stomach-intestine. One dorsal and two lateraloviducts connect the uterus with the cloaca. The maleâ¢apparatus is paired. On each sidebranched solid testicle strandslie in the parenchyma below theintestine and its branchings. Oneach side an anterior and a pos-terior vas deferens collect thesperm from the testes. Bothvasa deferentia enter a muscularlateral sperm vesicle, which liesbetween the 3d and 4th suckers,and which opens outwardly at theedge of the body. Prosopygia.âThe places offormation for the eggs and sperma-tozoa of the Sipunculidce, Phoron-i<li.i, and Brach

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