. Seaside studies in natural history. Marine animals. 54 MARINE ANIMALS OF MASSACHUSETTS BAT. state, forming slight projections at the base of the two other tubes. Fig. 66 gives a view of the animal from below, at this stage of its growth, while Fig. 65 shows it in profile. It will be seen by the latter how very spherical is the outline of the disk at this period, while the proboscis, in which are placed the mouth and digestive cavity, is quite long, and hangs down considerably below the lower surface of the disk. As the animal advances in age the disk loses its spherical outline, and becomes
. Seaside studies in natural history. Marine animals. 54 MARINE ANIMALS OF MASSACHUSETTS BAT. state, forming slight projections at the base of the two other tubes. Fig. 66 gives a view of the animal from below, at this stage of its growth, while Fig. 65 shows it in profile. It will be seen by the latter how very spherical is the outline of the disk at this period, while the proboscis, in which are placed the mouth and digestive cavity, is quite long, and hangs down considerably below the lower surface of the disk. As the animal advances in age the disk loses its spherical outline, and becomes much flat- tened, as may be seen in Fig. 67. It may be well to introduce here some explanation of the law ac- Fig. 67. cording to which the different sets of tentacles follow each other in succes- sive cycles of growth, since it is a law of almost universal application in Jelly- fishes and Polyps; and, owing to the smaller number and simpler arrange- ment of the tentacles in Oceania, it may be more easily analyzed in them than in many others, where the number and complication of the different sets of tentacles make it very difficult to trace their relation to each other dur- ing their successive growth. We have seen that the Oce- ania begins life with only two ten- tacles. These form the first set, and are marked with the number 1 in the subjoined dia- gram, which gives the plan of all the different sets in their regular order. The second set, marked 2, consists also of two, which are developed at equal distances between the first two, i. e. at right angles with them. The third set, however, marked 3, Fig. 67. Young Oceaaia, older than Fig. 65 } Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Agassiz, Elizabeth Cabot Cary, 1822-1907; Agassiz, Alexander, 1835-1910, joint author. Boston, J. R. Osgo
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