Dr. Murai Éva szerk.: Parasitologia Hungarica 22. (Budapest, 1989)

The density of microthriches increases gradually from the larval form through the neck region and the mature parts of the strobila. Such a trend was also described for Diphylloboth- rium latum (BRATEN 1968a, b). In Hymenolepis fraterna, on the other hand, STOTTSOVA (1983) found a constant number of microthriches but an increase in their length starting from the neck region up to the mature proglottids of the adult worm. There is a great variety in the form and structure of the microthriches. They are thin, filament-like at the bladder wall, shorter, mushroom-like in the neck region and reveal a form typical of most cestoda in the mature region i.e. cylindrical projections with sharpened apical end. These specificities in the form of the microthriches are most probably related to certain adaptations to the precise living conditions. Thus, the microthriches in the bladder wall are markedly elongated and finer which could be explained by the necessity of intensified absorption of nutritive substances of vital importance for the growth and development of the helminth. The presence of shorter microthriches with rounded tips over the neck region tegument might be an adaptation to the closer contact of this part of the strobila with the host tissue. While the scolex and the neck are deeply sunk in the host's intestinal microvilli, the rest of the strobila is somewhat more free-floating In the intestinal lumen. The elongation of the microthriches and the sharpening of their spines in the mature parts of the strobila are suitable to support the long, ribbon-like body of the worm near the host's intestinal epithelium as well as to overcome intestinal peristalsis and the flow of the intestinal contents.The spinelike structure of the microthriches aids the adhesion of the taenia to the intestinal microvilli. Elongation of the microthriches, on the other hand, Increases the absorptive surface, thus facilitating the access of nutrients to the tegument. We consider the presence of transversal connections between the microthriches in the bladder wall and the mature proglottids of the taenia to be necessary for the microthriches to remain parallel to each other. Such connections were not observed between the microthriches in the neck region of the strobila. There the microthriches are shorter and have more stable bases. The transversal connections were also described by FEATHERSTON (1972). He considered these connections to be identical with the branched microthriches described by UBELAKER et al. (1970) and HAYUNGA and MACKIEWICZ (1975). In conclusion, we can point out that along with the growth and development of the taenia considerable changes in the number, form and structure of the microthriches also take place. These changes depend on the tegument's digestive functions and on changes in the environment where the larval and the adult forms of the helminth are found, and once again prove the strongly manifested adapting abilities of the parasites. MIZINSKA-BOEVSKA Y., POLJAKOVA-KRUSTEVA O. és FOK É.: Transzmissziós- és pásztázó-elektronmikroszkópos megfigyelések Taenia hydatigena és borsókája, Cysticercus tenuicollis, kültakaróján (Cestoda: Cyclophyllidea) Taenia hydatigena aduit példányok és borsókáik (metacestoda stádiumuk) köztakarójának elektronmikroszkópos vizsgálata sorári a szerzők a strobila és a borsőka tegumentjének és különösen a mikrobolyhok morfológiájára összpontosították figyelmüket. Megállapítják, hogy a mikrobolyhok formája és struktúrája állandó (1-3. és 6-8. kép), de specifikusan adaptálódik a féreg egyedi fejlődéséhez (pl. az aduit féreg nyaki szakaszán, az erőteljesen osztódó zónában a mikrobolyhok rétege jellegzetes kialakulást mutat (4-5. kép).