A new species of polychaete, Stratiodrilus vilae, epizoic on Parastacus brasiliensis (von Martens, 1869) and P. defossus Faxon, 1898, is described from the State of Rio Grande do Sul, southern Brazil. The new species has one pair of long, anal, conical ventral lobes, one on each side of the anus, claspers in the males, and one pair of tubercles in each of the posterior locomotor appendages; and the jaw apparatus not reaching the limit between the head and the first segment.

Se extrajeron metazoos parásitos de 110 Chaetodipterus faber (Broussonet, 1782) (Teleostei: Ephippidae) del litoral del Estado de Rio de Janeiro, Brasil (aprox. 21-23° S, 41-45° W). Se describe e ilustra dos nuevas especies de monogéneos de los géneros Sprostoniella y Parancylodiscoides. La nueva especie de Sprostoniella difiere de S. multitestis, la otra especie del género, por 1. la disposición de los septos (con 17 septos, dos de ellos bífidos y dos incompletos en la nueva especie; 17 septos, dos de ellos trífidos en S. multitestis), 2. la nueva especie muestra dos lóculos centrales, mientras S. multitestis sólo uno, y 3. el primer par de ganchos en la nueva especie es pequeño y poco desarrollado, mientras que en S. multitestis es robusto y bien desarrollado. La nueva especie de Parancylodiscoides difiere de P. chaetodipteri, la otra especie del género, por 1. la forma del testículo (bilobulado en la nueva especie, no bilobulado en P. chaetodipteri), y 2. por la presencia de un reservorio prostático accesorio que alcanza la base del órgano copulador (ausente en P. chaetodipteri).

Metazoan parasites were extracted for 110 Chaetodipterus faber (Broussonet, 1782) (Teleostei: Ephippidae) specimens from the coastal zone of the State of Rio de Janeiro, Brazil (nearly 21-23° S, 41-45° W). Two new species of monogeneans belonging to genera Sprostoniella and Parancylodiscoides are described and illustrated. The new species of Sprostoniella, differ from S. multitestis, the only known species of the genus, by: 1. the arrangement of septa (with 17 septa, two of them bifid and two incomplet in the new species; 17 septa, two of them trifid in S. multitestis). 2. the new species showed two central loculi, while S. multitestis only one, and 3. the first pair of anchors of the new species is small and poorly developed, while in S. multitestis is well developed and strong. The new species of Parancylodiscoides differs from P. chaetodipteri, the only known species of the genus, by: 1. the testis shape (bilobated in the new species, not bilobated in P. chaetodipteri), and 2. by the presence of accessory prostatic reservoir at the copulatory organ base (absent in P. chaetodipteri).

Forty-three specimens of Umbrina canosai captured in the littoral of the State of the Rio Grande do Sul, Brazil, were examined between August 1991 and February 1992. Forty fishes (93%) showed infection by the acanthocephalan Corynosoma sp. (cistacanth) in the abdominal cavity and intestinal mesentery, with a mean intensity of 43.3, and relative density of 40.3 Corynosoma sp showed a overdispersed distribution. The intensity of Corynosoma was positively correlated with the host total length, but, the prevalence was not. The prevalence and intensity of Corynosoma sp. was not influenced by the host sex.

Quarenta e três espécimes de Umbrina canosai capturados no litoral do Estado do Rio Grande do Sul, Brasil, foram examinados entre agosto de 1991 e fevereiro de 1992. Quarenta peixes (93%) estavam infectados pelo acantocéfalo Corynosoma sp. (cistacanto) na cavidade abdominal e no mesentério intestinal, com uma intensidade média de 43,3 e uma densidade relativa de 40,3. Corynosoma sp. foi positivamente correlacionada com o comprimento total dos hospedeiros, mas, a prevalência não apresentou correlação. A prevalência e a intensidade parasitária de Corynosoma sp. não foram influenciadas pelo sexo dos hospedeiros

Two new species are described from the caiman. Caiman crocodilus yacare. Proterodiplostomum breve n. sp. differs from all other species in the genus by the following chacacteristics: (1) the paraprostate gland is shorter and club-shaped; (2) the genital cone is, in average, eight times longer than that of P. medusae; (3) the genital atrium is larger and without pseudosuckers; (4) the oral sucker and pharynx are longer; and (5) there are larger numbers of papillae surrounding the tribocytic organ (40) against 20 in P. longum, 16 in p. tumidilum, 8 in P. ophidum, and 16-18 in P. medusae. Proterodiplostomum globulare n. sp. differs from all the other species in the fenus by the following characteristics: (1) from P. tumidilum, P. lomgum, P. medusae, and P. breve n. sp. for the absense of pseudosuckers or muscular bunches in the inferior wall of the genital atrium; (2) the shape of the paraprostate gland, which is globular and not cylindrical as in P. longum, P. tumidilum, P. medusae, and P. ophidum; (3) the size of the tribocytic organ 201-407 long, 183-495 wide, while is 138-270 long, 102-292 wide in P. medusae, and 138-270 long, 255 wide in P. ophidum; (4) the number of papillae in the tribocytic organ (18-20) in P. globulare and 16-18 in P. medusae, and 8 in P. ophidum. Specimens belonging to six other species of proterodiplostomes are recorded for the first time infecting the caiman, C. c. yacare in the Pantanal Mato-grossense, Brazil, namely: Proterodiplostomum medusae, P. tumidilum, Cystodiplostomum hollyi, Prolecithodiplostomum constrictum, Paradiplostomum abbreviatum, and Herpetodiplostomum caimancola.

Pseudotelorchis caimanis n. sp. and P. yacarei n. sp. are described based on specimens collected from Caiman crocodilus yacare (Daudin) in the Pantanal Mato-grossense, Brazil. This is the first record of any species of Telorchiidae Stunkard, 1924, parasitizing crocodilians. Pseudotelorchis caimanis n. sp. differs from P. comapactus, the only species described in the genus with seminal receptacle, testes in tandem, and genital pore lateral to acetabulum. Pseudotelorchis yacarei n. sp. differs from the two other species for its body shape, for infecting the intestine instead of the uterus, by having regularly disposed instead of irregulary disposed uterine loops, and by having the vitelline glands disposed in longitudinal lateral lines instead of in lateral bunches.

Phyllodistomum rhamdiae n. sp. is described based on specimens collected from the urinary bladder of freshwater catfishes, Rhmdia quelen, caught from the Guandu river, outskirts of Rio de Janeiro, State of Rio de Janeiro, Brazil. The new species is characterized by its sucker width ratio equal to 1:1, by the large size of the gonads and their spatial arrangement.

Proctocaccum dorsale n. sp. is described and Caimanicola marajoara Freitas & Lent, 1938 is redescribed based on specimens collected from Caiman crocodilus yacare (Daudin) from the Pantanal Mato-grossense, State of Mato Grosso do Sul, Brasil. This report extends south ward the known geographic distribution of C. marajoara. It is the first record of the genus Proctocaccum in South America, and in the caiman. Proctocaccum dorsale n. sp. differs from the other eight species in the genus by the dorsal location of the anal openings, instead of being lateral or in the posterior extremity of the body.

Probursata brasiliensis n. sp., a gill filament parasite of carangid fishes, O. palometa (Cuvier), Oligoplites saurus (Bloch & Schneider), and O. saliens (Bloch), from the Brazilian coast, is described and illustrated. The new species differs from Probursata veraecrucis Bravo-Hollis, 1984, the type and only species of this genus by the presence of spines in the auricular expansions of the genital atrium, by the trifurcate supplementary process of the clamp's midsclerite, and by having a larger number of tests and clamps. This is the first record of the genus Probursata Bravo-Hollis, 1984, in the South Atlantic Ocean.