The origin of the sensory components of the cranial ganglia

Francis L. Landacre
1910 The Anatomical Record  
Professor Herrick has set before us clearly the principal conclusions derived from the attempt to analyze from a functional standpoint the cranial and spinal nerves, chiefly among the Ichthyopsida. The writer will confine himself to the inquiry as to what support these conclusions find in the development in a favorable type such as Ameiurus, laying emphasis largely upon the mode of origin and the morphological relations of the cranial ganglia, exclusive of the sympathetic ganglia. The ganglia
more » ... glia. The ganglia in the vertebrates are the source of the central and peripheral fibers which have been grouped into the various coniponent systems, and are in a very literal sense the foundation of these systems. Their niode of origin must affect vitally our conception of the theory of nerve components. The cat-fishes were chosen as a type, partly because the nerve components of the adult are known through Dr. Herrick's work, and partly because the character of the gustatory system is such that it seemed to be a favorable form in which to differentiate between the special visceral and general visceral systems of ganglia. In contrast with the favorable conditions offered by the embryo, the cranial nerves of the adult cat-fish are much more difficult to analyze than those of such a form as Menidia, but by going back to a stage between eighty and ninety hours after fertilization, we find the ganglia in such a simple condition, with so little fusion of the various ganglionic coniponents, that their analysis becomes comparatively easy. A t this stage (as shown in fig. 1 ) we find
doi:10.1002/ar.1090040204 fatcat:rxgmbzakvjhmpnpcmdpwaohn54