Dr. Murai Éva szerk.: Parasitologia Hungarica 14. (Budapest, 1982)
adjacent to the tunica externa and showed a pearl-like arrangement. These cysts contained mature spores. In August and September some of the cysts were already empty, but in the macrophage centres of the kidneys, free Thelohanellus-spores could be found. Regarding their shape and measurements the spores found in the swim bladder and the kidney were identical but significantly differed from those obtained from cysts developing in the fins . The Thelohanellus species found in the fins was identified as T. nikolskii Achmerov, 1955, the other found in the swimbladder wall as T. hovorkai Achmerov, 1960. The description of the two species on the basis of the examination of 30 spores each is the following: T . nikolskii (carp fin parasite): Cysts round, thickwalled (60-100 /im), with a diameter of 1. 0-2. 0 mm. Pansporoblasts irregularly rounded, disporous. Spores (Fig. 5) oval, somewhat narrowing anteriorly and slightly flattened frontally. There is only one short ellipsoidal, relatively small polar capsule in the spore. Spore wall thick, with suture well observable, emerging from spore surface at spore end. No mucous envelope. Spore length 17.5 (17-18.5) [im, width (in the plane of the suture) is 10.5 (10-11) .^m, and thickness (sutures up and down) 8.5 (8.3-8.7) „an. Polar capsule 6.8 (6.5-7.0) : m long and with a diameter of 5.5 (5.1-6.2) j.im. Suturai width at the ends of spores 1.7 (1.6-1.8) ;itn. T. hovorkai (swim bladder parasite): Cysts lensshaped with a thin wall of 10-15 ,m and a diameter of 2-3 mm. Developmental stages were not observed. Length and width of the spores (Fig. 6) nearly equal. From front-view spores oval shaped, slightly narrowing at the anterior end. From side-view an indentation can be seen bilaterally at the midportion of the spores. There is only one, relatively large oval-shaped polar capsule in the spores. Spore wall relatively thin, suture hardly observable. Spore surrounded by a thin, transparent mucous envelope starting from anterior end. Spore length 19.0 (18.7-19.5), width 8.5 (7.5-10.2) and thickness 8.4 (8.3-8.5) pm. Polar capsule 10.2 (9. 5-11.0) long and with a diameter of 7.5 (6.8-8.5) iim. Mucous envelope with a length of 24 and a width of 16 (l m. DISCUSSION During the present investigations two distinct Thelohanellus species were found in common carp. These parasites should be considered to be new members of the parasite faune of the Carpathian Basin. They were apparently introduced to the Trans Carpathian region of the Soviet Union and to Roumania by the introduction of the amur wild carp (Cyprinus carpio haematopterus) . The culturing of the amur wild carp and its hybrids in the abovementioned areas was described by PVASIK et al. (1970). The parasites presumably entered Hungary by active invasion through the River Körös or possibly the River Tisza. JENEY (1979), accepting SHULMAN's opinion (1962), identified the species living on the carp fins as T. dogieli. During our investigations, however, we obtained ample evidence to show that in contrast with SHULMAN's view T . nikolskii Achmerov, 1955 and T. hovorkai Achmerov, 1960 are undoubtedly valid, distinct species. The results of examinations made on several thousand fish have clearly revealed that T. nikolskii really is an organospecific parasite - as stated by ACHMEROV (1955, 1960) and that it develops exclusively on the fins, unlike T. dogieli which occurs on the skin of fish. The morphological characteristics found by us are also in agreement with those observed by ACHMEROV (1960), and significantly differ from the data given for T. dogieli . The only slight difference between ACHMEROV s and our data is that according to our results the spores of T. nikolskii are somewhat smaller. These data prove the validity of T. nikolskii while we consider the fin parasite species T. cyprini described in Japan to be synonymous with T. nikolskii. ; , The same conclusion was drawn in the case of the Thelohanellus species found in the swim bladder seröse. This species, as it was described by ACHMEROV (1960), develops in cysts on seroseous membranes, in our case on the swim bladder serose of the carp. On the basis of the characteristic, bilaterally indentated spores, the mucous envelope surrounding the spores, the shape of the large polar capsule and the measurements agreeing with those given in the original description, this species was easily identified as T . hovorkai .
