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ABSTRACT

The structure of the spermatozoon of Mugil curema Valenciennes, 1836 was studied using scanning and transmission electron microscopy. The spermatic head is rounded and formed by the nucleus containing granular chromatin, firmly packed resulting in a mass extremely electron dense. The acrossome is absent. The midpiece is characterized by the presence of two centrioles, a plasmatic canal, very few vesicles, and several mitochondria (9-10) with aproximately 0.50µm in diameter. The head and the midpiece are aproximately 1.56µm in diameter. The flagellum conforms to the 9 + 0 flagellar pattern near the transition region in its midpiece and is 9 + 2 from there on up to the distal region of the axoneme. The electron density in the A tubules 1, 2, 5 and 6 shows the asymetry of this spermatozoa. Its spermatic cell differs ultrastructuraly from those of other Mugilidae species mainly because it has the highest number of mitochondria

ABSTRACT. Gills of the seawater fi sh Cat/w raps spixii (Agassiz, 1829) were submitted to ro uti ne processing for observation in scanning and transmission electron microscopy. The wrinkled surface of the gill filaments showed well-defined cellular ultrastructures. Microridges on cellular surface were projected over all gill structures, including respiratory lamellae. Chloride cells were usually at primary lamellae. Some rod let cells were fo und. Mucous secretory cells were uncommon at all parts of the gill arches. The pharyngeal region of the gill arches showed a lot oftaste buds but no spines. There were smal l and strong rakers. Such morphology is indicati ve of fishes that swallow small food but do not have filtering habits. At the ultrastructural level the gills of TUARO et al. 1998; AZEVEDO et al. 1999), and it is found throughout the year on seashore of Parana State, southern Brazil.Morphological studies of fishes on the Brazilian seashore and continental waters, especially on gill ultrastructures, have begun just a few years ago (FERNAN-DES & PERNA 1995; MORON & FERNANDES 1996; EIRAS-STOFELLA & CHARVET-ALMEIDA 1997 MAZON et al. 1998; EIRAS-STOFELLA et al. 2001 ).The present research includes the morphologi cal description of the gills of C. spixii with the observation of ultrastructural detail s. The relations between the morphology of the gill s, the presence of certain cells, feeding habits, and some other characteristics of this species are also discussed. MATERIALS AND METHODSCathorops spixii fishes were coll ected in the Parana coast (Brazil), near the 25°32'S-48°28' W and 25°15 'S-48°20'W coordinates, with the use of trawl nets and lines.After anaesthetizing them (MS 222), the second gill arches (B all) of the collected fishes were extracted and fixed in a solution of buffered glutaraldehyde.