Studies on the Head Structure of Spirometra erinacei (Cestoda, Pseudophyllidea) Plerocercoid by New Stretching-Fixation Method
Development of new fixation method for maintaining the head region of Spirometra erinacei kept stretched in aqueous chemicals was worked out, and the external morphology of the well-stretched head of plerocercoid was studied under light and scanning electron microscopy. The stretching method for plerocercoid head was most effective when specimen was placed in 10% ethanol Ringer solution for 5 minutes after soaking several hours in 0.1% chloretone Ringer solution. In the plerocercoid head, the bothria and bothridia were clearly found on the dorsal and ventral surfaces, and a frontal pit was also found on the apical end in the same manner as that of some diphyllobothriid cestodes, Diphyllobothrium ditremum, D. dendriticum and D. vogeli. Morphological appearance of microtriches on the surface of frontal pit periphery were quite different from those of other parts of the head surface.
