. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Vl] THE NERVOUS SYSTEM 125 nerve-cells. The pons is a more slender commissure passing in the form of a flattened arch above the central body, and separated from it by an area carrying numerous tracheae. The large and deeply pigmented cerebral trachea (fig. 56 c, fr) ramifies in a fan-like manner upon and into the cortex of the brain, penetrating chiefly along the plane which appears to mark the original boundary between proto- and tritocerebrum. The most conspicuous formation in the procerebral lobes of the Dragonfly is th
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Vl] THE NERVOUS SYSTEM 125 nerve-cells. The pons is a more slender commissure passing in the form of a flattened arch above the central body, and separated from it by an area carrying numerous tracheae. The large and deeply pigmented cerebral trachea (fig. 56 c, fr) ramifies in a fan-like manner upon and into the cortex of the brain, penetrating chiefly along the plane which appears to mark the original boundary between proto- and tritocerebrum. The most conspicuous formation in the procerebral lobes of the Dragonfly is the much discussed pair of bodies known as the stalked bodies, mushroom bodies, or corpora fungiformia. Although these do not shew in the Dragonfly the very peculiar and specialized development which they attain in some other insects ( the social Hymenoptera), yet they are very strongly developed,. d Fig. 57. through right mushroom body of Aeschna brevistyla Ramb. ( x 60). cal calyx; cl cauliculus; gc giant nerve-cells. Original. particularly in the large Dragonflies, such as Aeschna (fig. 57). Each mushroom body consists of three parts, (i) a stalk or cauli- culus {cl), (ii) a calyx (cal) and (iii) a large mass of giant nerve- cells (gc). The stalk is a single short cylindrical mass of nerve-fibres arising vertically upwards from the medulla of the procerebral lobe, and terminating in the calyx. The calyx is a large undivided mass of small ganglion cells taking a very deep stain throughout. The cells of the calyx are arranged in more or less radiating lines, all closely packed together. The calyx forms a kind of external support or "raised back" for the giant cells, and is not folded into the "cup" shape more usually seen in the higher insects. The giant cells of the mushroom body are collected into a large mass placed internally to the calyx. These cells are flask-shaped, with. Please note that these images are extracted from scanned page images tha
Size: 2208px × 1132px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeenguniver
