Discovery reports (1934) Discovery reports discoveryreports09inst Year: 1934 232 DISCOVERY REPORTS for the size of the head. The ventral commissure is wider than the dorsal. The dorsal ganglia divide posteriorly into upper and lower branches. The small upper branches taper away rapidly while the lower become included in the cerebral organs which swell to form substantial lobes lying almost free at their hinder ends in blood sinuses formed from the lateral and median vessels. The ventral ganglia become the lateral nerves beneath the cerebral organs and leave their positions on either side of
Discovery reports (1934) Discovery reports discoveryreports09inst Year: 1934 232 DISCOVERY REPORTS for the size of the head. The ventral commissure is wider than the dorsal. The dorsal ganglia divide posteriorly into upper and lower branches. The small upper branches taper away rapidly while the lower become included in the cerebral organs which swell to form substantial lobes lying almost free at their hinder ends in blood sinuses formed from the lateral and median vessels. The ventral ganglia become the lateral nerves beneath the cerebral organs and leave their positions on either side of the rhynchocoel to pass down the body. Neurochord cells were observed in the cellular tissue of the inner face of the ventral ganglia just posterior to the ventral commissure. The cephalic slits are apparent very near the tip of the head. They do not extend posteriorly beyond the cerebral canals, which pass in directly opposite the lower cornua of the dorsal ganglia. As far as I am able to judge from the incomplete specimen the identification of this worm with C. aerugatus is justified. Cerebratulus fuscus, Mcintosh, 1873 (Plate XV, fig. 8; Figs. 9, 10). Eighteen specimens were taken during August and September. This species was fairly common in the kelp roots between tide-marks both inside and outside the Bay. The lengths varied between 2-3 and 3-5 cm. with breadths of o-8 and 1-4 mm. Speci- mens with eggs were collected on August 14. Form and colour in life. The body is a little flattened from above down. The head is flat, not distinctly marked off from the body, and it tapers to a blunt snout. The cephalic slits are very long and the mouth is small, placed at the end of the head behind the brain. The small eyes vary in number and are deeply embedded. There are usually ten visible on each side; five together near the tip of the snout, the others in a line farther back. A caudal appendage is present. The range of colour is from pale buff to a d pink or light red on the back wi
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