. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. NEMERTEANS 261 half the length of the body, but the rhynchocoel extends to the tail. The proboscis has twelve nerves. The armature consists of a main stylet on a base not longer than itself and two reservoirs, each with from four to seven stylets. The relative positions of the stomach, excretory organs and branches of the anterior caecum are believed to vary with the degree of contraction of the body. Thus in one series of sections the stomach wall is visible some distance before the brain, show
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. NEMERTEANS 261 half the length of the body, but the rhynchocoel extends to the tail. The proboscis has twelve nerves. The armature consists of a main stylet on a base not longer than itself and two reservoirs, each with from four to seven stylets. The relative positions of the stomach, excretory organs and branches of the anterior caecum are believed to vary with the degree of contraction of the body. Thus in one series of sections the stomach wall is visible some distance before the brain, showing that the alimentary canal has the power of independent movement and that not much reliance can be placed in distinguishing charac- ters based on position. The anterior caecum has branches which are first seen close behind the excre- tory tubules (Fig. 35). The vascular system consists of two lateral vessels forming a head loop and passing one on each side of the rhynchocoel through the brain region. They unite with a dorsal vessel by a transverse con- nection and pass down the body ventral to the nerves. There is a convoluted excretory tubule on each side close behind the cerebral organ, lying above the nerve and opening to the ex- terior by a single dorso-lateral duct. The brain is of good size. The dorsal ganglia are larger than the ventral and lie immediately over them. At the posterior end of the ventral ganglia there maybe a con-. Fig. 35. Amphiporus lecointei, Biirger. Diagram from a graphic reconstruction of the head and anterior end of the body to show the relations of the brain, cerebral organs, excretory and alimentary systems, ac, anterior caecum; co, cerebral organ; csg, cerebral subepithelial glands; dg, dorsal ganglion; e, eye- spots; ex, excretory tubule; hg, head glands; In, lateral nerve; phg, opening of the head gland; rd, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabili
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