1890.] 
471 
[Tuckerman. 
Francesco Todaro described, in the papillse covering the rudimen- 
tary tongue of Trygon pastinaca , a number of club-shaped bodies 
connected with the ultimate ramifications of the glosso-pharyngeal 
nerve, which he regarded as organs of taste, and analogous to 
those of mammals. E. Jourdan, in 1881, pointed out on the gills 
and in the buccal cavity of Peristedion cataphractum and other 
fishes cup-shaped bodies, composed of central and peripheral cells, 
which, in structure and position, differ completely from the or- 
gans of touch, and which he regards as gustatory organs. The 
goblet organs, or terminal buds as Merkel calls them, have been 
lately studied in Amia calva by E. P. Allis. They are present in 
large numbers on the external surface of the head, including the 
operculum, gular plate, and branchiostegal rays. They occur in 
the mouth and branchial cavities, and also extend on the top of 
the body as far as the dorsal fin. From the fact that the goblet- 
shaped sense-organs of fishes are not confined to the mucous 
membrane of the mouth, but occur in the skin at different parts of 
the body, Jobert, Merkel, and the later observers were led to re- 
gard them as organs of a tactile nature. 
Ley dig, in 1857, described in the epithelium covering the 
upper exposed surface of the fungiform papillae of batrachians, 
peculiar end-organs of the glosso-pharyngeal nerve. These sen- 
sory terminal organs, which received the name of taste-discs, have 
been studied in the Urodela and Anura. According to Key and 
Engelmann, the upper surface of each papilla fungiformis of the 
frog bears a taste-disc (or, as Merkel terms it, end-disc). These 
discs are composed of three kinds of cells, viz., cup-shaped, 
cylinder and forked, the latter alone being sensory in function. 
The fork-cells Engelmann considered the end-organs of the gusta- 
tory nerve, and probably directly continuous with non-medullated 
nerve-fibres, which, in their chemical reaction, they resemble. 
The taste-discs rest upon a stratum of modified connective tissue, 
the so-called “ nerve cushion,” to which medullated nerve-fibres 
run, and within which they lose their medullary sheath. 1 
1 Fajersztajn, in a recent paper on the terminations of the nerves in the end-discs of 
batrachians {Arch, de Zool. exp. et gen., t. vii, 2e Serie, 1889, p. 705), describes four kinds 
of cells in the disc, viz., cylinder, winged, forked, and staff-shaped. The forked cells, 
and not the staff-cells of Merkel, he regards as the true sensory elements of the disc. 
He believes in the contiguity, but not in the direct continuity, of nerve-fibrils and the 
central processes of the sensory cells. Contiguity being effected either by the terminal 
buds of the nerve-fibrils applying themselves to the bodies of the sensory cells, or by 
the central processes of those cells adhering to the nerve-fibrils of the subepithelial 
plexus. 
