. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 23o DISCOVERY REPORTS genital sacs, commenced about one-third of the length of the body from the anterior end. Form and colour of preserved specimens. The colour is bleached in spirit to a greyish white. No eyes are visible. The proboscis pore is terminal and the anterior end of the mouth is at the level of the pos- terior ends of the cephalic slits (Fig. 6A). Internal structure. Frontal organs were not seen although the tip of the head was sectioned. The muscle layers are arranged typically (Fi
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 23o DISCOVERY REPORTS genital sacs, commenced about one-third of the length of the body from the anterior end. Form and colour of preserved specimens. The colour is bleached in spirit to a greyish white. No eyes are visible. The proboscis pore is terminal and the anterior end of the mouth is at the level of the pos- terior ends of the cephalic slits (Fig. 6A). Internal structure. Frontal organs were not seen although the tip of the head was sectioned. The muscle layers are arranged typically (Fig. 6 B). There is a single vascular lacuna dorsal to the rhyn- chodaeum in the head. This divides and the two lacunae thus formed split up after the region of . Fig. 6. Lmeus ruber, O. F. Muller. A, head of spirit specimen, the ganglia into numerous vessels B> transverse section of body at the passing of the round the gut. The dorsal vessel excretory tubules to the exterior, protrudes into the rhynchocoel. The excretory tubules bulge into the large blood vessels on each side of the rhyn- chocoel. They occur a considerable distance behind the brain. Only one duct was found leading to the exterior on each side and it opened high up on the dorsal surface (Fig. 6B). From the persistence of the tubule in the last sections cut in series of this worm it is probable that further ducts were present. The number given by Punnett (i901) is from six to twelve on each side. The cephalic slits continue nearly to the tip of the snout and they disappear pos- teriorly as soon as the canal has entered the head. The fibrous tissue of the dorsal ganglion divides posteriorly into an upper branch which quickly disappears, and a lower which becomes invested with the cerebral organ and forms the posterior lobe of the brain. This lies almost free in a blood sinus at its hinder end. When the ventral ganglia merge into the lateral nerves they shift laterally from their position directly
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