. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. TYPRID NEUROANATOMY B 151. Figure 6. Compound eyes and frontal filaments. (A) The optic nerve (OpN) connects the compound eye (CE) to the optic lobe neuropil (OLN). (B) Frontal filaments are closely associated with compound eyes, and a transverse section through the base of a frontal filament (FF) is shown. The frontal filament tract (FFT) connects the frontal filament with the optic lobe neuropil proximal to the point of entry of the optic nerve (OpN) (see Fig. 5). (C) Scanning electron micrograph of the anterior ventral su
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. TYPRID NEUROANATOMY B 151. Figure 6. Compound eyes and frontal filaments. (A) The optic nerve (OpN) connects the compound eye (CE) to the optic lobe neuropil (OLN). (B) Frontal filaments are closely associated with compound eyes, and a transverse section through the base of a frontal filament (FF) is shown. The frontal filament tract (FFT) connects the frontal filament with the optic lobe neuropil proximal to the point of entry of the optic nerve (OpN) (see Fig. 5). (C) Scanning electron micrograph of the anterior ventral surface of a cyprid in which the cephalon is extended from the bivalve carapace. Frontal filaments (FF) extend from the ventral surface of the cephalon. posterior to the antennules. horizontal and longitudinal sections (Fig. 11 A, B). Paired nerve roots to the thoracic appendages extend from each thoracic division (Fig. 1 IB, C). Paired nerve roots extend to the caudal rami, but unlike those to thoracic appendages, are not associated with an obvious ganglionic division. Instead, these nerve roots appear to extend from a terminal loop of the longitudinal fibers (Fig. 11 A, D). Oral cone. The gnathopods of the cyprid form an oral cone, which opens to the ventral surface of the cephalon (Figs. 1, 2, 12A). The cyprid does not eat. and gnathopods are rudimentary during this stage (Walley. 1969). There are no obvious nerves connecting the gnathopods to the central nervous system in B. aiuphi trite. However, the posterior ganglion extends laterally in the region adjacent to the oral cone. It is likely that the three ganglionic divisions located adjacent to the oral cone reflect the presence of three pairs of gnathopods and are, therefore, referred to as subesopha- geal divisions. Esophagus and digestive system. The digestive system of the cyprid is not fully developed (Walley, 1969). The esoph- agus has an oral opening (Fig. 12A), but we found no evidence of a rostral opening of the dig
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
