The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . way either before or behind. The nervous system of Nassopsis (Fig. $7) ls extremelyinteresting, being one of the most archaic taenioglossate typesat present known. The cerebral ganglia are widely separatedfrom one another, and the pleural ganglia are not onlyseparated from the cerebral ganglia, but on the sides of theoesophagus, the cerebro-pleural connectives being conse-quently of considerable relative length. The supra-intestinalcord springs directly from the right
The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . way either before or behind. The nervous system of Nassopsis (Fig. $7) ls extremelyinteresting, being one of the most archaic taenioglossate typesat present known. The cerebral ganglia are widely separatedfrom one another, and the pleural ganglia are not onlyseparated from the cerebral ganglia, but on the sides of theoesophagus, the cerebro-pleural connectives being conse-quently of considerable relative length. The supra-intestinalcord springs directly from the right pleural ganglion, passes 254 THE TANGANYIKA PROBLEM. up over the oesophagus, and carries the supra-intestinalganglion. From the left pleural ganglion there passes a finenerve towards the supra-intestinal ganglion, which appearsto form a dyaloneurous connection with a derivative of thesupra-intestinal nerves. Towards the right the sub-intestinalconnective passes from the left pleural ganglion beneath theoesophagus straight to the sub-intestinal ganglion. Thisganglion is directly connected with the right pleural ganglion ^. Fig. 37.—The nervous system of Nassopsis g., Pedal ganglia. c. g., Cerebral ganglia. by a thick cord, and the nervous system is therefore stronglyzygoneurous on the right. Above, the cerebral gangliagive off a number of anterior nerves, which are distributedto the buccal mass and the parietes of the head. Amongthese there are conspicuous the tentacular nerves, which passseparately to the tentacles and ocular papillae. The buccalganglia are situated on the lateral walls of the buccal mass,and are united to the cerebral ganglia by connectives. Nearthe origin of the buccal nerves there arise two fine nerves,one from each cerebral ganglion, which pass forward along THE TANGANYIKA PROBLEM. 255 the walls of the body, and then bend down, uniting witheach other below the mouth. This connection appears,therefore, to be unquestionably the labial commissuredes
Size: 2327px × 1074px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectm, booksubjectzoology
