The present study was undertaken to determine the occurrence of virus particles in male accessory reproductive glands and to describe the changes in the affected tissues. Using electron microscopy techniques, it was possible to identify rod-shaped virus-like particles in accessory reproductive glands of male tsetse, Glossina morsitans morsitans Westwood. The viruses occurred intracellularly within the epithelial cells and in the lumen of the glands. Cell degeneration characterized by abundant clear vacuoles, membrane-bound vesicles, disorganization and elimination of cell organelles typified the infection. The inference, therefore, is that virus infection may be primarily responsible for the necrotic changes identified in the gland cells. It is suggested that the lesions caused in the gland epithelium by the infection would disturb the glandular cells and disrupt synthesis of the secretion. This may eventually destroy the male accessory reproductive glands leading to inability of the male flies to form spermatophores for transferring spermatozoa to the female tsetse. Lack of sperm transfer would consequently result in no egg fertilization.

The process of sperm penetration into the egg of the European catfish Silurus glanis L. was investigated by scanning and transmission electron microscopy. Unfertilized ovum membrane under the internal micropylar aperture shows a critical depression with undulation and short microvilli corresponding to a specialized sperm entry site structure. Twenty seconds after insemination, the fertilizing spermatozoon fused with the egg at this specialized structure, without formation of an earlier fertilization cone, which had been confirmed in eggs of other fish. A cytoplasmic eminence developed however, immediately under the fused sperm head and then disappeared with time after fertilization to form a circular area around the fused sperm head, which in turn became embedded in the circular area with shortening of the flagellum. The micropyle in the catfish egg consisted of a micropylar vestibule and a canal, the internal micropylar canal being wide enough to permit the penetration of only one spermatozoon.

Dans cette première note, 13 taxons, dont 5 endémiques de Nouvelle-Calédonie, sont examinés au microscope électronique à balayage (M.E.B.) et au microscope électronique à transmission (M.E.T.). La liste des espèces observées est la suivante : Amphipleura guillauminii, Achnanthes lata, Brachysera neocaledonica var. angusta (nov. comb.), Cocconeis neocaledonica, Cymbella delicatula, Cymbella subturgida, Denticula elegans, Epithemia cistula, Navicula bryophila, Navicula viridula var. rostellata, Stenopterobia intermedia, Surirella neocaledonica var. punctata. La structure de Cocconeis neocaledonica Maillard se révèle très originale.