Dr. Holló Ferenc szerk.: Parasitologia Hungarica 4. (Budapest, 1971)

following descriptions made on the basis of our own observations.

1

^ Classis: Cestodes 1 Ordo: Pseudophyllidea Carus Pamilia: Bothriocephalidae Blanchard Species: Bothriocephalus claviceps (Goeze, 1782) (Pigs. 1-2) Host: Anguilla anguilla L. Site of infection: Intestinal tract Locality and date of collection: Balatonfüred Bay, Lake Balaton, 25 July, 1968, leg. É. MURAI Intensity: 1-50 specimens Extensity of infection: 36 % (5 of 14 eels) Description: A medium-sized bothriocephalid. Total length 6-18 cm, maximum length of strobila 2.5 mm. Scolex 0.800-1.400 mm long, 0.320-0.380 mm wide, bearing two longitudinal pseudobothridia measuring 0.200-0.500x0.100-0.180 mm.In the living state, the scolex carries a well observable apical disk, but in certain positions this may be sunk into the muscles of the scolex, so that parasites fixed in this state appear to have an anteriorly rounded scolex. The segments are invariably wider than long, the ratio of length to breadth, varying according to maturity between 1:12-1:2. Dimension of immature young proglottides (not containing gonads) 0.060-0.100x0.480-0.600 mm; young hermaphroditic segments 0.080-0.200x1.100-1.700 mm, mature segments 0.340-0.660x1.800-2.500 mm; old segments containing mature eggs 0.600-0.750x1.600-1.800 mm. The phenomenon of secondary segmentation, which frequently occurs in Bothriocephalus species (PUHRMANN, 1933, p.

295), in observable in nearly every strobila of B. claviceps. The young proglottides, when still free of eggs, very frequently contain two reproductive systems, indeed, two pairs of gonad sets dis1

^The comparative morphological and anatomical investigations of the two species were carried out by the author in 1969 at the University of Neuchâtel in the Zoological Institute, led by Professor J.G. BAER.