. Outlines of zoology. Zoology. TYPES OF CCELENTERA—A SEA-ANEMONE. 147 so that food particles from the gullet may pass into any of the chambers between the partitions. Moreover, each partition is perforated, not far from the mouth, by a pore, besides which there is often another nearer the body wall. The tentacles are continuous with the cavities between the mesenteries, and thus all the parts of the body are in communication. The mouth is usually a longitudinal slit, and its two corners are often richly ciliated. The gullet is marked with longitudinal grooves, two of which, the " siphono
. Outlines of zoology. Zoology. TYPES OF CCELENTERA—A SEA-ANEMONE. 147 so that food particles from the gullet may pass into any of the chambers between the partitions. Moreover, each partition is perforated, not far from the mouth, by a pore, besides which there is often another nearer the body wall. The tentacles are continuous with the cavities between the mesenteries, and thus all the parts of the body are in communication. The mouth is usually a longitudinal slit, and its two corners are often richly ciliated. The gullet is marked with longitudinal grooves, two of which, the " siphonoglyphes," corres- pond to the corners of the mouth, and are especially broad and deep. Along these two grooves, and by these two corners, food particles usually pass in; '"£^V /*j^:.a.^m .m/- but in some, one side is fp"~^li? a'^^^SsF 3 an incurrent, the other an l^^Sr^H & ^j^^fpm*. excurrent channel. Occa- sionally only one corner of the mouth and side of the gullet is thus modified. » The gullet often extends FlG. through sea- far down into the cavity of anemone (across arrow in Figure the anemone. It admits 64).-After Andres. Of a Certain amount Of A±,B> directive septa ; , mesenteric m. filaments; £-.} genital organs; ? extrUSlOn. 1 he mesenteries longitudinal muscles; s., primary bear-fa) mesenteric fila- ^^;s:b^ween mentS ; (b) retractor two primary septa (an intra-septal muscles ; (c) ridges of repro- £&* J&J""" °ut betwee" ,w° ductive cells, almost always either ova or spermatozoa, rarely both ; and (d) in some cases offensive threads or acontia. The mesenteric filaments seem to be closely applied to the food, and perhaps secrete digestive juice. Intracellular digestion also occurs. Sea- anemones have no sense organs; the sapphire beads, which are so well seen at the bases of the outermost tentacles of the common Actinia mesembryanthemum, are batteries of stinging cells. T
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
