. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 480 G. F. GWILLIAM failure after about four similar shadows. This is in contrast to Lcpas, where adaptation to multiple shadows appears to take place at the level of the supra- esophageal ganglion rather than the ventral ganglion (Gwilliam, 1962). Records taken from close to the ocellus result in an ERG similar in form to the others already noted, and a similar response is recorded from the median nerve (Fig. 8, C, D). The fact that the median nerve in this species serves as a photoreceptor was discovered by accident. During
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 480 G. F. GWILLIAM failure after about four similar shadows. This is in contrast to Lcpas, where adaptation to multiple shadows appears to take place at the level of the supra- esophageal ganglion rather than the ventral ganglion (Gwilliam, 1962). Records taken from close to the ocellus result in an ERG similar in form to the others already noted, and a similar response is recorded from the median nerve (Fig. 8, C, D). The fact that the median nerve in this species serves as a photoreceptor was discovered by accident. During a routine experiment to establish the obvious lateral ocellus as the sole photoreceptors, recordings were taken from the circum- esophageal nerve before and after severing the ocellar nerve at the level of the. FIGURE 8. Balanus cburncus. Electrical events recorded from the circumesophageal con- nective (A and B), the ocellar nerve (C), and the "median" nerve (D). Time marker in A applies also to B; time and amplitude in C applies also to D. A. C. recording. ocelli, and a good shadow response was evident (Fig. 9, A). Then, all four lateral nerves were severed at the ganglion (the circumesophageal connectives having been severed previously), and the median nerve was cut distal to the small ganglion. Under these circumstances, a good shadow reflex was still obtainable (Fig. 9, B, C). The median nerve was then severed just proximal to the small distal ganglion, leaving a length of nerve which apparently itself was photosensi- tive, for a good response was still observed (Fig. 9, D). Finally, cutting the median nerve at the level of the supraesophageal ganglion abolished the response (Fig. 9, E). The function of this small median ganglion as a photoreceptor is not universal in B. eburneus, for not all preparations show this activity. It is even less common. Please note that these images are extracted from scanned page images that may have been digitally enhanced for read
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
