Studies on the poisonous spider, Chiracanthium japonicum, as a pest of medical importance : 3. Functional and histological studies on the venom apparatus

Abstract

Arachnidism caused by the genus Chiracanthium has been reported from subtropical or warm temperate zones in all over the world. So far in Japan, total 50 cases of arachnidism caused by C. japonicum, which is recognized to be most dangerous, were recorded and analized epidemiologically from the medical points of view up to 1976. The investigation was made on the function and the histology of the venom apparatus for the purpose of analysing the cause of arachnidism. The venom apparatus is associated with the chelicerae or first pair of appendages of the cephalothorax. Each consists of a large basal segment and a terminal claw-like fang piecerced by the duct from the venom gland. The fang of male is about two times longer than that of female, therefore, the fangs of male was found to be able to penetrate the palmar skin of volunteer more deeper than that of female. The muscularis was found to cover the whole gland beginning from the neck of the gland. This is the bundle of fibers of striated-muscle. The basement membrane from a continuous layer under the muscularis. The two kinds of epithelial cells were observed lining the basement membrane. The first layer is formed by small and low cells with an ovarial nucleus. The second layer is formed by high columnar cells attaching on the basement membrane. Both the nuclei of the first and the second cells show the same morphological structure by the optical microscopy.