Rare and remarkable animals of Scotland, represented from living subjects: with practical observations on their nature . scis isoutermost if the individual be uppermost in the roll; thus all lie in thesame direction, the proboscis outermost, as the Medusa escapes, from thenext left behind. When the last remains in adhesion to the fleshy bulb,its proboscis projects outwards also. Thus the under surface of the em-bryo is always outwards, while a portion of the roll. This is a singular arrangement: it shews that Nature designs that thematurity of the embryos, and their liberation into active life
Rare and remarkable animals of Scotland, represented from living subjects: with practical observations on their nature . scis isoutermost if the individual be uppermost in the roll; thus all lie in thesame direction, the proboscis outermost, as the Medusa escapes, from thenext left behind. When the last remains in adhesion to the fleshy bulb,its proboscis projects outwards also. Thus the under surface of the em-bryo is always outwards, while a portion of the roll. This is a singular arrangement: it shews that Nature designs that thematurity of the embryos, and their liberation into active life, should besuccessive. Whether the brood be confined within some invisible amnios,collectively or individually, in an earlier or later stage, is uncertain. The period occupied by the change, and that which is consumed inthe dissolution of an entire roll, is extremely variable. It usually takesseveral days. But I have seen a single Medusa free itself within threeminutes after its precursor departed. The higher two of Plate 16, separated during observation. The four higher of Plate XIX. ?v;i. ; XIX. n. -- c- 4-iU^> I. r yVi//u^i/^^a ^IV^/ua SOi/zda^^ d rr .!Vli /« -?«? MEDUSA BIFIDA. 125 fig. 8, having become more amply developed, as in fig. 9, were under suchvehement exertion at noon, soon after obliteration of the tentacula, thatI felt impatient for the arrival of my artist to delineate the whole subject?while yet entire, which he accomplished.—Fig. 9. Accordingly, two to-gether were liberated just as the drawing was completed. After strugglingseverely, they were free of each other. Many days sometimes elapsebefore dissolution of the roll as previously observed. When a drawing of Plate XX. figs. 6, 7, was begun, the lower partof the roll was merely a smooth swelling whirl; but previous to comple-tion of that and another, the conversion of the whirl to an early embryonicMedusa was perceptible. In nine days the whole Medusas of this subject,fig. 7, were liber
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectzoology, bookyear1847
