. Animal physiology. Physiology, Comparative; Physiology, Comparative. STRUCTURE OF ACALEPLLE OR JELLY-FISH. 109 a single aperture, which serves both to take in food, and to cast forth the indigestible remains. This character will be found to pre- vail among all the inferior Radiata. The amount of sensation pos- sessed by the animals of this class, has been already noticed (§. 79). 130. In the second group of Radiata, forming the class of Acaleph^e or sea-ueltles, the body is entirely soft and jelly-like ; containing so small a quantity of solid matter, that, when taken out of the water, so th
. Animal physiology. Physiology, Comparative; Physiology, Comparative. STRUCTURE OF ACALEPLLE OR JELLY-FISH. 109 a single aperture, which serves both to take in food, and to cast forth the indigestible remains. This character will be found to pre- vail among all the inferior Radiata. The amount of sensation pos- sessed by the animals of this class, has been already noticed (§. 79). 130. In the second group of Radiata, forming the class of Acaleph^e or sea-ueltles, the body is entirely soft and jelly-like ; containing so small a quantity of solid matter, that, when taken out of the water, so that its fluid drains away, there is scarcely anything left. Hence, the animals of this class are commonly termed jelly-fish. They derive their other name of Sea-Nettles from the stinging power which most of them possess. They are formed to float freely through the water; but they do not in general possess any means of actively propelling themselves through it. The radiated arrangement is very regularly pre- served in some of this group, whilst it is less evident in others. The accompanying figure represents one of the medusa tribe, as seen floating in water. The umbrella-shaped disc above contains the sto- mach, which is placed in the centre, and which opens by a single orifice or mouth, directed down- wards. Around the sto- mach are four chambers, in which the eggs are pre- pared. The mouth is surrounded by four large tentacula, which bring to it the necessary supply of food ; and other tentacula are seen, in this species, to be hanging from the edo-e of the disc. In the o edge of this disc, the nutri- tious fluid, which flows in F'«- 7!.-Pklagia. channels excavated out of the soft tissues, seems to be exposed. 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 Carpenter, William Benjamin, 1813-1885. London :
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