Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 27. (Budapest, 1994)

were fixed and stored in 70 % ethanol, stained in borax-carmine, dehydrated, cleared and mounted in Canada balsam. The slides are deposited in the Helminthological Collection of The Hungarian Natural History Museum, Budapest. Drawings were made with the aid of a camera lucida. Measurements and scales are in micrometers. RESULTS AND DISCUSSION Species descriptions Petasiger grandivesicularis Ishii, 1935 Host: Tachybaptus ruficollis Site: small intestine Locality: Hortobágy National Park Leg: O. Sey (15.08.1967) Description (measurements in pm; Figs 1 A, B): Small, fusiform trematodes. Body 973-1022 long, with maximum breadth 419 at acetabular level, covered with minute sharp spines. Oral sucker ventroterminal, 54-76 x 68. Prepharynx 36 long; pharynx 58 x 54; oesophagus 86 long; intestinal bifurcation close to genital pore. Ventral sucker large, situated at midbody, 223-281 x 259-274. Head collar 151-158 x 212-216, bearing 19 spines ( with arrangement 4-11-4). Two groups of 4 angle spines in ventral lappets measuring 85-97 (mean 90) x 11-14 (mean 12). Lateral and dorsal spines arranged in a single uninterrupted row, 47-61 (mean 56) x 9-11 (mean 10). Testes two, oval, smooth, situated obliquely to tandem in posterior body third. Anterior (left) testis 180-209 x 144-148; posterior (right) testis 194-256 x 119-126. Cirrus sac large, 144-216 x 216-220, containig bipartite seminal vesicle (the larger saccular part measuring 58-90 x 54) and very well developed pars prostatica whose large, intensively stained cells mask the invaginated cirrus and the upper part of the seminal vesicle. Ovary dextral, oval, 101-122 x 97-104; Mehlis' gland diffuse, 72 x 130; uterine seminal receptacle present. Vitelline follicles large, in two ventro-lateral fields fusing ventrally in front of the cirrus sac. Uterus short, containing 8-9 eggs. Remarks: Since the original description of P. grandivesicularis based on Japanese material from Tachybaptus ruficollis japonicus (Ishii 1935) the species has been recovered only from Tachybaptus spp. in Japan (Yamaguti 1939), Tadzhikistan (Borgarenko 1984), China (Chen Hsin Tao et al. 1985) and Bulgaria (Kostadinova et al. 1988). Thus the first record of P. grandivesicularis for the Hungarian fauna represents the second finding of this species in Europe. Coupled with the life-history data (see Kostadinova and Chipev 1992), our results indicate that the geographical distribution of P. grandivesicularis is much wider than previously believed. Cankovic et al. (1983) described P megacanthum from P. cristatus and T. ruficollis collected at Lake Skadar (former Yugoslavia). It seems probable that the description given by the above authors was based on a composite of the species