Abstract The Euphobia milii var. hislopii latex has been tested in the control of schistosomiasis but its action in the locomotor activity of Biomphalaria glabrata is unknown. The objective of this work was to study the locomotor and reproductive behaviors of B. glabrata exposed to E. milii var. hislopii latex. For this, 96 snails were individually exposed to the latex (LC50 - 0.53 mg / L) for 24 hours. The specimens were submitted to biomonitoring for image analysis to record the locomotor parameters at different times: before exposure (control), one day post exposure (group 1 d-p-e) and 30 days post exposure (group 30 d-p-e). The reproductive parameters were recorded weekly for 10 weeks. All locomotor activities of group 1 d-p-e decreased significantly. The egg/egg mass ratio decreased the week after exposure while there was an increase in the hatching rate. After 30 days, these reproductive parameters were similar to those observed in these same snails before exposure. However, the number of hatched snails declined after exposure until the end of the experiment. The influence of the latex in the parameters of B. glabrata added further evidence that this natural water-soluble product can be an important tool for the control of schistosomiasis.

A diplectanid monogenean, Acleotrema lamothei n. sp., is described from the gills of the yellow sea chub Kyphosus incisor (Cuvier, 1831) in Brazilian waters off Rio de Janeiro State. This species is distinguished by the facts that the male copulatory organ is armed with spines throughout most of its length, the ventral hamuli have a very long, stout outer root, which is slightly notched proximally, an inner root less than half the length of the outer root and a fine blade and point. It also differs from most species of the genus by the greater size of the haptor and its hard parts. This is the first record of a species of Acleotrema Johnston and Tiegs, 1922 from South American waters.

Se describe Acleotrema lamothei n. sp. de las branquias del pez Kyphosus incisor (Cuvier, 1831) recolectado en las costas del estado de Río de Janeiro, Brasil. La nueva especie se distingue por la armadura del órgano copulador con espinas en casi toda su longitud, por la presencia de una raíz externa larga y robusta en el hámuli ventral, provista de una pequeña muesca proximal, por la raíz interna que mide menos de la mitad de la longitud de la externa y por tener la hoja y la punta finas. Asimismo, difiere de muchas de las especies del género por el gran tamaño del haptor y de sus partes esclerozadas. El presente constituye el primer registro de una especie de Acleotrema Johnston y Tiegs, 1922 en aguas sudamericanas.

Caballerocotyla lenti n. sp. (Monogenea: Capsalidae), recovered from the gills of Auxis thazard (Lacépède) captured off the coast of Rio de Janeiro, Brazil, is described using light and scanning electron microscopy. The new species is characterized by: a tegument with 2-5 rows of dorso-marginal, unicuspid spines; 53-54 round testes; a constricted pharynx with numerous papillae on its border; and a haptor with a plicate marginal border, a central polygonal area and seven complete septa. C. manteri (Price, 1951) and C. gouri Chauhan, 1953 sensu Murugesh (1995) are figured and commented upon.

Pseudempleurosoma gibsoni n. sp. (Monogenea: Ancyrocephalidae) is described from the oesophagus of Paralonchurus brasiliensis (Steindachner) from off the coast of Brazil. The type-species of Pseudempleurosoma Yamaguti, 1965, P. carangis Yamaguti, 1965, is redescribed and the diagnosis of the genus is amended. Metadiplectanotrema Gerasev et al. 1987 is considered synonym of Pseudempleurosoma. This genus now contains four species, including P. carangis, P. caranxi Gerasev et al., 1987 n. comb., P. myripristi Gerasev et al., 1987 n. comb. and the one new species.

The gastrodermis of Atriaster heterodus Lebedev & Paruchin, 1969 (Polyopisthocotylea), a gill parasite from Diplodus argenteus (Valenciennes, 1830), is composed of "U"-shape hematin cells and a connecting syncytium, both having cytoplasmic lamellae. These cells show outgrowths and bent folds which were seen to enclose lumen material. The trapped material was then subjected to endocytosis. The nature of ingested food material was comparatively analyzed by cytochemical and histochemical tests. Blood residues were detected in the gut but tests for mucins were negative. No intact erythrocytes were observed in the gut lumen.