. The Cambridge natural history. Zoology. 120 NERVOUS SYSTEM those great lobes of the brain that are directly connected with the faceted eyes must not be taken into account in a considera- tion of the relation of the size and development of the brain to the intelligence of the individual. The weight of the brain in Insects is said by Lowne to vary from j^^ to -jinJTJ '^^ *^^ weight of the body. Figure 65 gives a view of one side of the supra-oesophageal ganglion of the worker of an ant,—Formica rvfa,—and is taken from Leydig, who gives the following elucidation of it: A, primary lobe, «, homog
. The Cambridge natural history. Zoology. 120 NERVOUS SYSTEM those great lobes of the brain that are directly connected with the faceted eyes must not be taken into account in a considera- tion of the relation of the size and development of the brain to the intelligence of the individual. The weight of the brain in Insects is said by Lowne to vary from j^^ to -jinJTJ '^^ *^^ weight of the body. Figure 65 gives a view of one side of the supra-oesophageal ganglion of the worker of an ant,—Formica rvfa,—and is taken from Leydig, who gives the following elucidation of it: A, primary lobe, «, homogeneous granular inner substance, b, cellular envelope; B, stalked bodies (gyri cerebrales), a, b, as before; c, presumed olfactory lobes, c, inner substance, d, gang- FlG. G6. — Stomato - gastric nerves of Cockroach : A, with brain in situ, after Koestler ; B, with the brain removed, after Miall and Denny : , supra- oesophageal ganglion ; n, optic nerve ; a, antennary nerve ; , frontal gang- lion ; oe, oesophagus ; c, connective; , paired ganglia ; , crop or ven- tricular ganglion ; r, re- current lionic masses; D, ocular lobes, e, f, g, h, various layers of the same; e, origin of lateral commissures; F, median commissure in interior of brain; g, lower brain (sub-oesophageal ganglion); //, ocelli; j, faceted eye. Besides the brain and the great chain of ganglia there exists an accessory system, or systems, sometimes called the sym- pathetic, vagus, or visceral system. Although complex, these parts are delicate and difiicult of dissection, and are consequently not so well known as is the ganglionic chain. There is a con- necting or median nerve cord, communicating with the longi- tudinal commissures of each segment, and itself dilating into ganglia at intervals; this is sometimes called the unpaired system. There is another group of nerves having paired ganglia,. Please note that these images are extracted from scanned page images that may have been d
Size: 1677px × 1489px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
