Text-book of comparative anatomy . ts and 8 (in Campodea 7) ganglia of theabdomen (Fig. 324). The finer structure of the last and largest abdominal ganglionand the number of nerves proceeding from it show that it consists of 3 fused number of abdominal ganglia would according to this be 10, corresponding withthe number of segments. In the Collembola the number of abdominal segments isreduced, and in accordance with this reduction of the body there is, as it appears,only 1 abdominal ganglion. Sminthurus is said to have only 1 thoracic 2 longitudinal commissures remain d
Text-book of comparative anatomy . ts and 8 (in Campodea 7) ganglia of theabdomen (Fig. 324). The finer structure of the last and largest abdominal ganglionand the number of nerves proceeding from it show that it consists of 3 fused number of abdominal ganglia would according to this be 10, corresponding withthe number of segments. In the Collembola the number of abdominal segments isreduced, and in accordance with this reduction of the body there is, as it appears,only 1 abdominal ganglion. Sminthurus is said to have only 1 thoracic 2 longitudinal commissures remain distinctly separate in the each ganglion 2 nerves are given off on each side, and the same number proceedfrom the cesophageal commissures. In front of the infra-cesophageal ganglion andbehind the cesophagus a transverse commissure connects the cesophageal —The nervous system of the winged Insecta shows very greatvariety in its arrangement: it is impossible here to go into details—the Diptera. FIG. 325.— A-B, The nervous systems of 4 species of Diptera, to demonstrate their variousdegrees of concentration. A, Non-concentrated nervous system of Chrionomus plumosus, with 3thoracic and 6 abdominal ganglionic masses. U, Nervous system of Empis stercorea, with - thoracicand 0 abdominal ganglionic masses. C, Nervous system of Tabanus bovinus, with one thoracicgauglionic mass and the abdominal ganglia moved towards each other. D, Nervous system ofSarcophaga carnaria. All the ganglia of the ventral chord except the infra-cesophageal ganglion,which always remains separate, are here united into one single thoracic ganglion mass (after ). (Fig. 325, A-D) are particularly instructive. In no other natural order of insectsare the extremes so great, and yet connected by such numerous intermediate series begins with the suborder of the Nemoccra, the Culicidce, Culiciformes,Tijnilidce, Funrjicolce ( Chironomus, A], which have very s
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
