. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 306 D. SANDEMAN ET AL. and other sensilla o i >rsal carapace (Kinnamon, 1979). Posterior i • re (PMNv): Projecting from the posterior o lie median nerve carries interneu- rons }•>••'• ..in and the oesophageal ganglion. Brain /> and Neuropils (Fig. I) There are three main divisions of the brain, protocere- brum, deutocerebrum, and tritocerebrum, reflecting the three ganglia that have fused to form it. The neuropils of the optic ganglia and lateral protocerebrum are located in the eyestalks of crayfish, crabs, and lob
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 306 D. SANDEMAN ET AL. and other sensilla o i >rsal carapace (Kinnamon, 1979). Posterior i • re (PMNv): Projecting from the posterior o lie median nerve carries interneu- rons }•>••'• ..in and the oesophageal ganglion. Brain /> and Neuropils (Fig. I) There are three main divisions of the brain, protocere- brum, deutocerebrum, and tritocerebrum, reflecting the three ganglia that have fused to form it. The neuropils of the optic ganglia and lateral protocerebrum are located in the eyestalks of crayfish, crabs, and lobsters. The median protocerebrum and tritocerebrum are located medially. Protocerebrum The protocerebrum can be conveniently subdivided into three parts, the optic ganglia, the lateral protocere- brum and the median protocerebrum. OPTIC GANGLIA. Contains three neuropils that are probably devoted to processing the information received by the photoreceptors of the retina. Lamina (L): The first neuropil behind the retina, the lamina is geometrically structured. External medulla (EM): Lying directly behind the lam- ina, the external medulla is similarly geometrically struc- tured, but is also transversely layered. Internal medulla (IM): The most proximal of the three neuropils in the optic ganglia, this too is geometrically organized and has clearly defined transverse bands. LATERAL PROTOCEREBRUM. Contains two neuropils. In crayfish, crabs, and spiny lobsters the neuropils of the lateral protocerebrum lie in the distal segment of the eye- stalk, directly proximal to the optic ganglia. In some an- omurans the lateral protocerebrum is incorporated into the centrally located median protocerebrum. Terminal medulla (TM): This complex neuropil is not geometrically organized but has a number of subdivisions (Blaustein ct a/., 1988). It contains neurosecretory cells of the X-organ and its associated neurohaemal organ, the sinus gland, which together constitute one of the most impo
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
