. -{£=â - cm Fig. 13. Zygonemertes capensis, Head, dorsal Fig. 14. Zygonemertes capensis, Part of a surface, cleared in anilin oil to show the three transverse section highly magnified, e, epithelium groups of eyespots. containing sickle-shaped bodies; bm, basement membrane; cm, circular muscle layer; /?«, longi- tudinal muscle layer. The oesophagus opens into the rhynchodaeum before the brain. In the region of the ganglia the oesophagus widens. Farther back it opens into the stomach with dark- stained granules in the cells of the folded walls and on each side appears a branch of
. -{£=â - cm Fig. 13. Zygonemertes capensis, Head, dorsal Fig. 14. Zygonemertes capensis, Part of a surface, cleared in anilin oil to show the three transverse section highly magnified, e, epithelium groups of eyespots. containing sickle-shaped bodies; bm, basement membrane; cm, circular muscle layer; /?«, longi- tudinal muscle layer. The oesophagus opens into the rhynchodaeum before the brain. In the region of the ganglia the oesophagus widens. Farther back it opens into the stomach with dark- stained granules in the cells of the folded walls and on each side appears a branch of the anterior caecum. These two diverticula do not reach the brain. There is a vascular loop in the tip of the head. In the brain region the lateral vessels are widened, their walls become definite and they are connected with the dorsal vessel above the gut. The three vessels pass down the body and join again above the gut just before the insertion of the rhynchocoel into the body wall. The excretory vessels he above the lateral nerves behind the brain. A single duct on each side opens to the ex- terior opposite the nerves. The ganglia are not peculiar, but the brain is rather large (Fig. 15 A). The lateral nerves give off branches which pass round the rhynchocoel, and at the posterior end of the body they join above the gut anterior to the anus. The cerebral canals open ventro-laterally a little way behind the opening of the oesophagus into the 4-2
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
