The elasmobranch fishes (1934) The elasmobranch fishes elasmobranchfish03dani Year: 1934 THE ELASMOBRANCH FISHES 281 ceptor cells, as hexagonal plates, line the ampulla. They are apparently not provided with hair-like processes which extend into the ampuUary cavity but each pyramidal cell has a sensory nerve (o/.) leaving from the apex of the cell. A motor axone (ef.) extends to each of the secreting or flask-like cells. In their development the ani- pnllary organs, like the long ca- nals, form as pits of the epider- mis. These pits sink deeply into the integument and often extend far forward
The elasmobranch fishes (1934) The elasmobranch fishes elasmobranchfish03dani Year: 1934 THE ELASMOBRANCH FISHES 281 ceptor cells, as hexagonal plates, line the ampulla. They are apparently not provided with hair-like processes which extend into the ampuUary cavity but each pyramidal cell has a sensory nerve (o/.) leaving from the apex of the cell. A motor axone (ef.) extends to each of the secreting or flask-like cells. In their development the ani- pnllary organs, like the long ca- nals, form as pits of the epider- mis. These pits sink deeply into the integument and often extend far forward or backward forming more or less elongate tubules. At the end of the deepest part the tubule swells out, forming an am- pulla of Lorenzini. The vesicles of Savi found in Torpedo consist of from one hun- dred to two hundred hollow sacs in the region of the nasal pit and ventrally between the cartilage of the pectoral fin and the electric organ. Each vesicle is a transformed canal organ which, unlike an ampulla of Loren- zini, is unconnected with the exterior. Such a vesicle is composed of three discs, one of which is large and occupies a median position while at the sides of this are two lateral and smaller ones. Pit Organs In addition to the above-mentioned organs, pit organs found in sharks and rays may here be descril)ed. These organs were early seen in the rays along the back just mediad of the lateral line and from the suprascapular line to the Fig. 248. Section showing ending of nerves (h.) in ampulla. (From Eetzius.)
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