. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. KIRKFLY LARVAL LUMINESCENCE 235 through the intersegmental membrane between the sixth and seventh abdominal segments. The spatula was placed in the basal segment of a glass Y-tube which was 30 mm. long and 1 cm. in diameter. Oxygen and nitrogen were led into oppo- site branches of the Y-tube through paired two-way stopcocks which permitted rapid shunting of the oxygen from the animal. Gas mixtures were prepared from commercial compressed nitrogen and oxygen metered through two-stage reduction valves and calibrated Fishcher-P
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. KIRKFLY LARVAL LUMINESCENCE 235 through the intersegmental membrane between the sixth and seventh abdominal segments. The spatula was placed in the basal segment of a glass Y-tube which was 30 mm. long and 1 cm. in diameter. Oxygen and nitrogen were led into oppo- site branches of the Y-tube through paired two-way stopcocks which permitted rapid shunting of the oxygen from the animal. Gas mixtures were prepared from commercial compressed nitrogen and oxygen metered through two-stage reduction valves and calibrated Fishcher-Porter flow7 meters. Composition was checked by gas analysis with a Scholander analyzer. Commercial compressed nitrogen, referred to hereafter as "; was found to contain no more than oxy-. FIGURE 1. Stimulated glow and pseudoflash of Photuris larva. In this and all subsequent experiments except where noted: Upper trace is photomultiplier output; middle trace heavy line is 21% oxygen and narrow line is nitrogen; marks on narrow segment are time base, 1 mark per second, reading from left to right. Lower trace: stimulus, 5 volts, 20 msec, dura- tion, 10 per second frequency. Electrode pair inserted in 6th abdominal segment in this and all subsequent experiments of larval light response. gen which was considered to be a negligible amount. A photomultiplier tube (RCA 931-A) and dissecting microscope were positioned above the animal and both were shielded from stray light by black cloth. In preparation for a pseudoflash one valve was rotated 180° to shunt oft the oxygen and admit either nitrogen or a nitrogen-oxygen mixture. Rotation of this stopcock also opened a signal circuit. At an appropriate time the same valve was then rotated back 180° which allowed a higher concentration of oxygen to reach the animal suddenly and also closed the signal circuit. The pseudoflash was de- tected by a photomultiplier, the output of which was led to one or both
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
