The porifera and coelentera . ts features intermediate between thoseof hydroid (scyphistomoid) and medusoid forms. It is eitherpurely free-swimming (Tessera), or has the power of temporaryfixation (Haliclystus) by the alioral pole. The organism is goblet-shaped, with a narrow stem which endsconically (Tessera), or in a disc (Haliclystus) which can be usedfor adherence to a solid object. The inaimhrium is well developed,but no velum is present. The edge of the bell is either (1) simple,and provided with four perradial and four interradial fcniaclcs 62 THE SCYPHOMEDUSAE (Tessera), to which eight
The porifera and coelentera . ts features intermediate between thoseof hydroid (scyphistomoid) and medusoid forms. It is eitherpurely free-swimming (Tessera), or has the power of temporaryfixation (Haliclystus) by the alioral pole. The organism is goblet-shaped, with a narrow stem which endsconically (Tessera), or in a disc (Haliclystus) which can be usedfor adherence to a solid object. The inaimhrium is well developed,but no velum is present. The edge of the bell is either (1) simple,and provided with four perradial and four interradial fcniaclcs 62 THE SCYPHOMEDUSAE (Tessera), to which eight adradial (Tesserantha) or even more maybe added ; or else (2) is divided by incisions into eight hollowadradial lappets ; on each lappet is seated a bunch of capitatetentacles, and between the lappets lie perradial and interradialmarginal anchors or colletoci/stophores (Haliclystus, Fig. 3), whichare, however, absent in some genera (Lucernaria). The marginalanchors are modified and shortened tentacles, at the base of each cc. Fk;. 2. Diagrams illustrating the stnicture of Lucprnaria. 1, longitiulinal section ; the riglithalf passes along an adradins, just missing a niesenterj, which is shown in thin outlineand carries gastric filaments and generative organs ; the left half passes along an interradiusand shows the course of a subunibral pit deeji into the substance of the mesentery. 2, transversesection ; the right half at the level of the stoino<laiUm, the left half a little below that level,and through thi- ujiper part of the subunibral jiits. 3, transverse section ; the right half throughthe lower part of the subunibral pits, the left half through the of the animal where the fourniesi-nteries fuse, centrally dividing the coelenteron into four pouches. In all three figures ecto-derm is strongly hatcheil, endoderm lightly hatche<l, niesogloea black. C, coelenteron ; CC,circular canal; G, genital organ ; GF, gastric lilament; /, interrmlius; LM, ectodennal longi-tud
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Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectctenophora
