. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CYPRID NEUROANATOMY 145 associated with each of these structures have not been traced back to the central nervous system. The cyprid is well equipped to detect settlement cues, but little is known about the underlying role of the nervous system. Recent studies have suggested that cyprid settle- ment behavior is affected by exposing cyprids to certain neuroactive substances (Clare et ai, 1995; Kon et ai, 1995; Yamamoto et ai. 1995, 1996: Okano et ai. 1996, 1998). Studies aimed at investigating the underlying mechanisms of set
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CYPRID NEUROANATOMY 145 associated with each of these structures have not been traced back to the central nervous system. The cyprid is well equipped to detect settlement cues, but little is known about the underlying role of the nervous system. Recent studies have suggested that cyprid settle- ment behavior is affected by exposing cyprids to certain neuroactive substances (Clare et ai, 1995; Kon et ai, 1995; Yamamoto et ai. 1995, 1996: Okano et ai. 1996, 1998). Studies aimed at investigating the underlying mechanisms of settlement would benefit from a detailed account of the cyprid nervous system. We report here the results of an anatomical study of the central nervous system and the major sense organs of the cypris larva of B. amphitrite. gained from microdissection, semithin serial sections, and electron microscopy. We find that the central nervous sys- tem is made up of about 2000 neurons and that it contains regionalized neuropils, many of which are linked to periph- eral sense organs. Although the cyprid nervous system is small, it is well organized, which is consistent with the cyprids' need to detect and respond to multiple cues for settlement. Materials and Methods Cyprids used in this study were obtained from a labora- tory culture of Balanus amphitrite (see DeNys et ai, 1995). The selected individuals were between 1 and 3 days old (nauplius-cyprid molt = day 0), were active, and had clear (, non-milky) carapaces, obvious cement glands, and compound eyes. Dissection of the animals provided a useful overview of their structure, including the placement of the antennules and limbs within the bivalved carapace and the gross organization of internal organs. Specimens were placed on a stereomicroscope and dissected using tungsten microscalpels and pins (Conrad et ai, 1993). Individuals were placed in a calcium-free saline (in mmol • 1~', 485 NaCl, 13 KC1, 10 MgCU 10 HEPES, pH ) to red
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
