. A text-book of invertebrate morphology. Invertebrates. 98 mVERTEBUATE MORPHOLOGY. into sense-organs (Fig. 50, s) situated near the margin of the bell and more or less enclosed in special chambers by the growth around them of folds of the bell substance (Z). From the centre of the subumbrella there hangs the manubrium (m), the extremity of which is frequently prolonged into four elongated mouth-lobes, and above it communicates with the gastric cavity, g, which in simple forms extends to the margin of the bell, being obliterated only at four interradial points or lines. The four broad radial p
. A text-book of invertebrate morphology. Invertebrates. 98 mVERTEBUATE MORPHOLOGY. into sense-organs (Fig. 50, s) situated near the margin of the bell and more or less enclosed in special chambers by the growth around them of folds of the bell substance (Z). From the centre of the subumbrella there hangs the manubrium (m), the extremity of which is frequently prolonged into four elongated mouth-lobes, and above it communicates with the gastric cavity, g, which in simple forms extends to the margin of the bell, being obliterated only at four interradial points or lines. The four broad radial pouches thus produced correspond with the radiating canals of the craspedote medu- sae, and the line of fusion being imperfect at the margin of the. Fig. 50.—Diagbam of Sctphomedusa. g = gastric cavity. r = reproductive organs. I = lolie covering the sense-organ. s = sense-organ. m = month. tg — subgenital cavity. mf = mesenterial filaments. i = tentacle. bell a communication between adjacent pouches is present comparable to the craspedote circular canal. This condition is, however, only retained in the simpler forms; in the higher ScyphomedussB the lines or points of obliteration may be omitted, and by secondary obliterations taking place over various areas of the coelenteron, and by its irregular extension towards the rim of the bell as this grows in diameter, a com- plicated branching arrangement of the peripheral portion of the coelenteron is produced, in which, however, the original 4-radial arrangement is as a rule distinctly indicated. Along the interradial axes there are four deep depressions of the subumbrellar surface, the funnds or subgenital chambers (Fig. 50, sg), above which lie the horseshoe-shaped reproductive organs, r, developed in the coelenteric endoderm, one limb of each horseshoe lying in each of the adjacent radial Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colo
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
