THE OBLONGATA AND THE NUCLEI OF THE CHANIAL NEBVES. 89 



tufts, innumerable delicate leaf-like appendages of the skin which completely 

 mask the lazy ambushed fish, so that it appears like a flat stone overgrown 

 with lichen and corals. Lying thus in the mud the angler lets its worm-like 

 decoy float above it. The whole cutaneous region involved in these curious 

 structures is, in fishes, supplied by the Vagus and Trigeminus. Fritsch, to 

 whom we are indebted for much of our knowledge of the flsh-brain, found 

 that the nuclei of these nerves in Lophius — and in this fish alone — ^were 

 supplemented by immense ganglion-cells which sent their neuraxons into 

 the nerves. We have to deal here, evidently, with hypertrophy of the 

 dorsal cells which lie near the periphery of the cord. These cells are so large 



Fig. 48. — Medulla of the Torpedo. Section from the region of the vagus nucleus. 



in Lophius that they require for their nutrition separate little capillary 

 loops, which lie among the cells. 



But still more interesting is the much-studied large nucleus which is 

 found in the electric ray, far forward in the floor of the fourth ventricle, 

 projecting into its cavity. This nucleus gives origin to the electric nerves, 

 one on each side. This paired structure, frequently fused anteriorly, con- 

 tains besides several small multipolar cells, a great number of gigantic gan- 

 glion-cells, which all send their neuraxons out into the electric nerves. 



With our present knowledge of the nuclei of the selachian brain it is 

 difficult to give these structures a positive interpretation, but the prob- 

 abilities indicate strongly that we have to deal here with nothing else than 



