• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.21-29
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• 1984

A scanning eletron microscopic study was performed to observe the tegumental surface of adult Fibricola seoulensis. The adult worms were collected from the small intestine of mice 5 days to 3 weeks after experimental infection with the metacercariae. The metacercariae were obtained from the viscera of the snakes, Matrix tigrina lateralis, by artificial digestion technique. The results were as follows: 1. The tegument of anterior body was covered with cobblestone-like cytoplasmic processes and that of posterior body showed finger-like processes. The posterior body had 4-5 large transverse wrinklings which formed many discontinued shallow rugae. 2. The entire surface of anterior body was regularly arranged with the spines of which tips diverged into 3 to 4 points. They were densely packed in anterior mid-median portion of dorsal surface where appeared a few spines indented upto 5 points. Farther laterally and posteriorly from this portion, the pointed spines were more sparse and became single tipped and extended to anterior one-third of posterior body, 3. The posterior surface of oral sucker was armed with 50-60 spines having 2-3 tips and ventral sucker also covered with such spines. On anteriormost dorsal surface arranged 60-70 spade-shaped spines. The tribocytic organ was armed with many stout recurved pile-like spines arranged radially. 4. There were 3 types of sensory papillae. The ciliated knob-like (Type I) papillae were almost bilaterally symmetrical in ventral and dorsal surfaces of anterior body, and abundant especially aroundbases of oral and ventral suckers, tribocytic organ, and in lateral margins of anterior body. About 24 non-ciliated round swellings (Type II) were observed around each lip of oral and ventral suckers. The plate-like elevated papilla without cilium (Type III) was found to distribute only in posterior body. These 3 types of papillae seem to be tangoreceptive and/or rheoreceptive in function when their morphology and distributions are considered.

• Parasites, Hosts and Diseases
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• v.32 no.2
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• pp.65-74
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• 1994

Surface ultrastructure of Pawctrema timonnauini developmental stages was studied using a scanning electron microscope. The metacercariae were collected from the marine clam, Topes phiLippinam and juvenile and adult worms were recovered at 1, 2, 3 and 7 days after experimental infection of mice. The metacercariae had a large oral sucker and characteristic lateral projections. Around the lip of the oral sucker many type I and type II sensory papillae were observed, and type III papillae were located symmetrically on the medial side of the lateral projection. Numerous type I papillae were grouped around the genital pore. The tegumental spines were distributed over the worm surface except the lip of the suckers and genital pore. The 1-day old worm had a well-developed ventral sucker, with 6 type II sensory papillae on its outer surface and another 6 type I papillae on the inner side. Two small type I papillae were seen on the anterior side of the ventral sucker. The genital pore was small and opened separately from the ventral sucker and 15 type I papillae were grouped around it. The 2-, 3-. and 7-day worms revealed that as they grew to be adults, the spine tips became multipointed, the genital pore formed a genital atrium, and the cytoplasmic process became well differentiated. In 2- and 3-day worms 10 type II papillae encircling the lip of the oral sucker, and additional 4 papillae at the dorsal side of 4 dorsal type II papillae were a characteristic feature. The distribution pattern of sensory papillae around the oral sucker and genital pore, and 2 type I papillae on the anterior side of the ventral sucker, was so peculiar in R timonnnuini, that they seem to be useful keys for taxonomic differentiation from other gymnophallids.