. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 474 G. F. GWILLIAM The fact that shadow "intensity" and magnitude of the response are related is illustrated in Figure 3. Shadows were cast with gelatin neutral density filters having per cent transmission characteristics indicated in the upper right hand corner of each record. It can be seen that cutting out 60% of the incident light results in what is essentially a full shadow reflex (compare Figure 3, C and F). (b) Lepas anatifera. This species exhibited responses similar to those of Mitclla polymcrns, but it wa
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 474 G. F. GWILLIAM The fact that shadow "intensity" and magnitude of the response are related is illustrated in Figure 3. Shadows were cast with gelatin neutral density filters having per cent transmission characteristics indicated in the upper right hand corner of each record. It can be seen that cutting out 60% of the incident light results in what is essentially a full shadow reflex (compare Figure 3, C and F). (b) Lepas anatifera. This species exhibited responses similar to those of Mitclla polymcrns, but it was also possible to record directly off the ocellar nerve in Lepas (Fig. 4). Records from the circumesophageal connectives and stalk nerves showed considerable spontaneous activity, but there was none of the regular rhythmic activity of the type shown by Alitella stalk nerves. This may reflect the rather different behavior patterns of the two animals. Mitella is a barnacle that lives attached to rocks, along with Mytilus califoniianus. It feeds by extending the cirri into a moving stream of water during high tide and is exposed at low water, during which time the cirri are inactive. Even during feeding, Mitella. FIGURE 3. Mitella. The effect of casting shadows with neutral density filters. Figures in upper right hand corner of each record indicate per cent transmission of the filter used to cast the shadow. Recorded from the stalk nerve. does not exhibit the regular extension and retraction "fishing" activities so typical of sessile barnacles, and it is possible that the regular rhythmical activity observed in the stalk and mantle motor nerves serves to provide regular pulsations of the muscles that aid in blood circulation in these heartless crustaceans. Lepas, on tin; other hand, lives attached to ships and floating timber and is at all times submerged. Lepas feeds much as does a sessile barnacle, by the regular extension and retraction of the cirri, and this activit
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
