Abstract
It is of interest that, in the mucous membrane of the pharynx of Japanese snapping turtle, my so-called pharyngeal papillae resembling the lingual papillae may be found in quantity. The epithelium covering them is of an unhornified stratified flat type and the subepithelial connective tissue lacks mucuous glands. Longitudinal mucous folds are in formation in the oesophagus, covered by a stratified cylindrical epithelium and containing intraepithelial mucous glands. The lamina muscularis mucosae is absent; the tunica muscularis consists of an inner layer of longitudinal striated muscle fibres and an outer layer of circular smooth muscle fibres, but the former is formed only in the lateral sides of the oesophageal wall.
In the pharyngeal papillae, as in the lingual, well-developed nerve plexus composed of numerous sensory fibres and vegetative fibres is in formation. Small ganglia are found in this plexus as well as well as in the submucosal and the proprial plexus in the vicinity of the papillae. The ganglion cells in these ganglia are of sympathetic nature showing weak multipolarity but many of them are apparently apolar. The vegetative fibres end as always in STÖHR's terminal reticula in the pharyngeal mucous membrane of snapping turtle too.
No corpuscular or complex branched termination but only unbranched and simple branched terminations were found here. These are formed in the stocks of the pharyngeal papillae usuall beneath their epithelium, and originate mostly in medium-sized medullated fibres. Their terminal fibres run either nearly straight or looped courses and usually end sharply, but not rarely some end in small endknobs. Intraepithelial fibres are demonstrable in a very small number and are very poorly developed, penetrating only as far as into the basal layer of the epithelium before ending.
My so-called perioesophageal plexus formed in the adventia of the oesophagus, interestingly enough, contains small ganglia in some places. AUERBACH's plexus rich in ganglia is found between the outer and the inner muscle layers and MEISSNER's plexus in the submucosa, and what is of highest interest is that ganglion cells are found in the MEISSNER's plexus here in a much larger quantity than in man and mammals.
It is needless to reiterate that the ganglion cells found in these plexuses are of sympathetic nature as those in the pharyngeal mucous membrane above and here too the fine vegetative fibres participating in the composition of these plexuses form STÖHR's terminal reticula as their terminations.
A rather large number of thick sensory fibres are found in the plexus of the oesophagus too. Most of these run from the submucosa into the propria and end there, mostly beneath the epithelium. Their terminations comprise no such corpuscular or complex branched types as found in the human oesophagus, but only unbranched and simple branched (chiefly bifurcated) types, as in the pharynx, with terminal branches ending sharply or bluntly but never forming such end-knobs or intraepithelial fibres as found in the pharynx. Thus, the sensory fibres found in the oesophagus of snapping turtle are far poorer than the same in its pharynx, in quantity as well as in terminal mode.
