. The annals and magazine of natural history : zoology, botany, and geology. length. The section passes to one side of thestomodaeum. above, and the mesogloea of the latter is continued down thecentre as a kind of supporting axis; the other two are hereshown free from the disk, though in other sections the con-tinuity is shown. Fig. 2 represents a section through thestomoda?ura of another polyp; here the single downgrowthto the lett clearly corresponds in position with the normaltentacular upgrowth to the right and is much longer. Morpliulogy of the Madreporarii. 4Gi) The transverse section dc
. The annals and magazine of natural history : zoology, botany, and geology. length. The section passes to one side of thestomodaeum. above, and the mesogloea of the latter is continued down thecentre as a kind of supporting axis; the other two are hereshown free from the disk, though in other sections the con-tinuity is shown. Fig. 2 represents a section through thestomoda?ura of another polyp; here the single downgrowthto the lett clearly corresponds in position with the normaltentacular upgrowth to the right and is much longer. Morpliulogy of the Madreporarii. 4Gi) The transverse section dcpicttiJ in fi^. 3 proves that thethree or<^ans occur at what is known as the dorsal border ofthe polyp, one being within tlie dorsal directive entocojle andone within the cxocccle on each side of the directive entocoehi,cxac:ly as described by Krcnipf for the lied Sea sections of some polyps they occupy nearly the entiremesenterial chamber, while in others they are so enlarged asto result in disturbances of the mesenteries by pressing u{)ontheai. Fig. Vertical section through a polyp. The section pass\s through thostomotlauni, and includes a retracted normal tentacle on the rightand a luoditied invaginated tentacle on tlie left. An examination of a large number of pol^ps reveals thatthe dowiigrowths are not always three in number; sometimesthere are only two, and in other instances only one, but nevermore than three occur. In the polyp represented in sectionby tig. 4 only one downgrowth is present, situated in theexocade to the right of the dorsal directive entocoele. Thepolyp is moi*e retracted than that from which tig. 3 was taken,and the intrusion disturbs the regularity of form of themesenteries and stomocheum. As noticed by Krenipf, the modification occurs in oidy alimited number of the many poly[)s making up a colony; the * There is possibly some confusion as regards the terms dorsal andYi-ntral. Krenipf states that the media;) organ in Jucino/wra oc
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Keywords: ., bookcentury1800, bookids7annalsmagazi, booksubjectnaturalhistory
