Papers from the Tortugas Laboratory of the Carnegie Institution of Washington, Volume 3Carnegie Institution of Washington, 1911 |
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Papers from the Tortugas Laboratory of the Carnegie Institution ..., Volume 18 Visualização completa - 1922 |
Termos e frases comuns
Acetic acid alkalinity Alpheid Anal arm rods animals Annelids aquarium Arbacia arm-buds beat behavior body calcium Carnegie Institution Cassiopea Cassiopea xamachana cease cilia ciliary movement cleavage color contraction Cradactis variabilis cross-fertilization crosses Ctenophores depressant Direction of locomotion Directly to lighted dish Disk diameter Echinoderm Echinus effect embryos experiments fertilization fronds geotropism Herbst Hipponoë hybrids Institution of Washington ions larvæ lattice structure lighted end loggerhead turtle lymphatic magnesium maternal medusa Mellita MgCl2 minutes Moira molecular move muscles NaCl nerve neuro-muscular movements neuro-muscular system neustes normal nuclei obtained optimum oral-arms palolo worm parthenogenetic Pentaceros Physiol plate plutei posterior lymph hearts potassium pulsation rays reaction regeneration sea-water+ shown side skeleton sodium solution species specimens sperm Sphærechinus sponge starfish stimulation Strongylocentrotus surface temperature Tennent tentacles tests tion tissue Tortugas Toxop Toxopneustes Toxopneustes X Hipponoë trochophores tube feet veins Vernon worm
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Página 86 - Anatomischer Anzeiger, Band 32, S. 533 and 542. vertebrates is very incomplete. Favaro (1906) and Allen (1907, 1908) have done much to clarify our knowledge concerning the relations between the lymphatic and the blood vascular system in fishes. Much more work of this kind is greatly needed to fill up the many gaps still existing in our knowledge of the lymphatics of lower vertebrates. The literature of the ontogeny of the lymphatic system of lower vertebrates is still more scanty. Outside of the...
Página 106 - THE DIRECTION OF LOCOMOTION. So far as I know, Jennings (1907) has been the first to attempt to ascertain whether the direction of the rays of light or the differences in the intensity of illumination on the different parts of the body determine the direction of locomotion of the starfish. By manipulating a screen in various ways, so as to cut out the direct action of the sun's rays on the surface of the starfish, Jennings obtained results which point strongly to the view that the "relative intensity...
Página 79 - Miiller (1839) and in the large land turtles by Fritsch (1874), their development, as far as is known to the writer, has never been studied. Recently, the most general interest has been attached to the development of the lymphatics in general. But the results obtained have been by no means in accord. On the contrary, the most divergent conceptions have arisen through the study of the mammalian type alone. It has therefore seemed to the writer desirable to refer to a more generalized type of vertebrate,...
Página 31 - FIO. 1. Stimuli are constantly arising in the sense-organs in dish A, and pass along the strip of tissue stimulating the muscles as they go. By slowly raising or lowering the temperature of the sea -water in B, a temperature can be found where contraction of the muscles ceases, yet the impulse is still transmitted. A cessation of nerve...
Página 144 - In one case it was found in 1 per cent and in the other in 3 per cent of the plutei examined. In other crosses it occurred as occasional variation. The pure cultures made in 1909 and 1910 as controls for the hybridization experiment showed an occasional pluteus with this variation, but the number was never great enough to exclude the advisability of considering the common appearance of more than one rod, a Hipponoe character, as an indication of Hipponoe influence.
Página 139 - FLORIDANA <? : (1) The Toxopneustes eggs were allowed to stand for 2 hours and were then fertilized with Holothuria sperm. A fertilization membrane was formed at once. A small percentage of segmentation was obtained. (2) Toxopneustes eggs were treated with MgCl2 (1 cc to 100 cc sea-water) for 3 minutes. Segmentation began 45 minutes after fertilization with Holothuria sperm. (3) Toxopneustes eggs treated with COa for 4 minutes and fertilized with Holothuria sperm 50 minutes after transference to...
Página 128 - Strongylocentrotustf he considered in detail the effect of changes in temperature on the character of the skeletal rods of the anal arms and on the number of "roots" of anal arm supports, defining these roots as any outgrowth from the horizontal part of the oral bar, anal crossbar, or body-skeleton directed into the anal arm. For the purpose of comparing Herbst's results with my own I include parts of four of Herbst's tables, Nos. Ill, VI, X, and XII (1906, pages 192, 203, 225, 230). Temp. Temp....
Página 116 - ... and figured those which seem of greatest interest are the intestinal caeca. These, as above stated, were found in some instances to be greatly distended, stimulation causing their contraction. Upon allowing individuals, from which the aboral wall had been removed, to remain undisturbed in sea-water, the organs again became distended and later contracted of their own accord. In this behavior we have support to the idea of the analogy of the intestinal caeca of the starfish to the respiratory trees...
Página 125 - Differences in temperature, (2) Differences in concentration of sea-water, (3) Differences in light, (4) Chemical agents. Strongylocentrotus eggs were placed in water of 8° or 25° C. for an hour, or even for a minute, at the time of impregnation. After 8 days the resulting plutei were 4.4 per cent smaller than those from eggs FIG.
Página 75 - ... (2) After entering the water, the animal swims out to sea, apparently attracted by the darker blue of the deeper water. The position of the sun is an entirely negligible quantity. (3) When on the beach in a large sand-pit with level floor, from which pit sight of the bushes and the ocean is excluded, but into which the sun's rays shine directly, there is exhibited no definite tendency to move in any definite direction.