File:A history of the British sessile-eyed Crustacea (1863) (14803056543).jpg

Identifier: historyofbritish12bate (find matches)
Title: A history of the British sessile-eyed Crustacea
Year: 1863 (1860s)
Authors: Bate, C. Spence (Charles Spence), 1818-1889 Westwood, J. O. (John Obadiah), 1805-1893
Subjects: Crustacea Malacostraca
Publisher: London : J. Van Voorst
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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s to beformed out of the anterior pairs of pleopoda, just asis the case in the Brachyura, among the Stalk-eyedCrustacea. These observations are further confirmed bythose of M. Rousel de Vauzeme on the genus Cyanius. In the Isopoda, these organs have been carefully workedout by Siebold, LerebouUet, and Schobl. In the genusLigia (Fig. 16), we have observed on each side three testes, consisting of long narrowvesicles, tbinning away toexquisitely fine filamen-tary prolongations. Thesevesicles increase in dia-meter as they approachtowards the efferent duct,where they rapidly be-come constricted beforeuniting with the vas defe-rens. These vesicles arefilled with seminal cells,and are, we believe, thetrue testes. M. Lere-bouUet, however, in hisresearches on the Onis-cid(2,^ states that he hasobserved that each ofthese fusiform sacs hasattached to its extremity other irregular sacs, whichhe regards as the principal secreting organs, and con-sequently the spermogenic glands or testicles. These
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* Mem. sur les Crustaces de la Famile des Cloportides, par A. Lerebonllet.Strasburgh, 1852. INTRODUCTION. xli orgaus, which have previously escaped the observation ofanatomists, the author says, are very irregular sacs,variable in form, simple or compound; they are generallyabout three-quarters of a millimetre in length, but some-times less. They are situated deeply on each side thestomach, and are retained in their position by delicatebut strong ligaments, which are covered with black pig-ment, which lose themselves between the muscular fasciseof the segments of the body. These organs are full ofcells, that M. Lereboullet considers as the spermaticcellules. The second vesicles, or those which we thoughtto be the true testes, M. Lereboullet calls testicules acces-soires. They are, he says, three in number on each,enlarged towards the middle; they thin out insensiblytowards the extremities: at one end they unite with theorgans that M. Lereboullet calls the testes, and at theother they

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