. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. no A. S. PEARSE. The light reactions of the commensals were tested. Animals were placed in a flat dish containing sea water. This dish was barely enclosed by a box two feet long and sixteen inches wide. The box was painted black on the inside and light was admitted through an aperture two inches high across the lower side of one end. When a Pinnixa or a Polyonyx was placed in the box before a window it usually went toward the light and tried to get through the glass for a time. It soon began to wander about the dish, however
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. no A. S. PEARSE. The light reactions of the commensals were tested. Animals were placed in a flat dish containing sea water. This dish was barely enclosed by a box two feet long and sixteen inches wide. The box was painted black on the inside and light was admitted through an aperture two inches high across the lower side of one end. When a Pinnixa or a Polyonyx was placed in the box before a window it usually went toward the light and tried to get through the glass for a time. It soon began to wander about the dish, however, and after twenty-four hours spent most of the time in the darkest end of the box. When ten individuals of the same species were put in the dish simultaneously their behavior was essentially the same. Twenty Pinnixa and seven Polyonyx were left together in the box several days. When the lamp was lighted before the opening of the box at night most of the crustaceans went toward it and tried to get through the end of the glass dish, but after an hour they became scattered about the dish without particular reference to the light. Mast. FIG. 6. Pinnixa undergoing ecdysis. The left-hand figure shows a ventral, the right-hand a dorsal view. ('ii, p. 284) mentions several animals which, though usually negatively phototropic, may become positive for a time after mechanical or other stimulation. Apparently steady light is not, as a rule, an important factor in the daily life of Pinnixa and Polyonyx, but if confined under unnatural conditions they may go toward a light. Such reactions might enable them to escape from confinement. Both Pinnixa and Polyonyx responded readily to a decrease in light intensity. The former was very active when placed in a glass dish and kept its legs continually in motion; but if an object was passed between it and the window it became motionless at once. Though Polyonyx was more. Please note that these images are extracted from scanned page images that may h
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
