An ultrastructural study of spermatogenesis and sperm morula breakdown inArenicola marina (L.) (Annelida: Polychaeta)

AN ULTRASTRUCTURAL STUDY OF PLANT SPERMATOGENESIS Spermatogenesis in Nitella

Spermatogenesis in the charophyte Nitella has been followed in antheridia prepared for light and electron microscopy. The antheridial filament cells contain paired centrioles which are similar in structure and behavior to the centrioles of animal cells. In the early spermatid, the centrioles undergo an initial elongation at their distal ends and become joined by a spindle-shaped fibrous connect...

An Ultrastructural Study of Plant Spermatogenesis

Spermatogenesis in the charophyte Nitella has been followed in antheridia prepared for light and electron microscopy. The antheridial filament cells contain paired centrioles which are similar in structure and behavior to the centrioles of animal cells. In the early spermatid, the centrioles undergo an initial elongation at their distal ends and become joined by a spindle-shaped fibrous connect...

The Eyes and the Photonegative Behaviour of Nephtys (annelida, Polychaeta)

Foraging and mobility in three species of Aciculata (Annelida: Polychaeta).

Aspects of feeding, such as food capture and ingestion, as well as mobility of the polychaetes Eurythoe complanata, Marphysa formosa and Diopatra aciculata, from São Sebastião Channel (São Sebastião, state of São Paulo) were observed in laboratory conditions. Eurythoe complanata, a carnivorous species, fed exclusively on pieces of fish with the aid of strong muscular retractable lips, and detec...

A morphometric analysis of Eunice Cuvier (Annelida, Polychaeta) species

Morphology has been the subject of several studies in Eunice specially in the context of the taxonomy and evolutionary relationships of taxa within this genus. In this study we opt for a morphometric approach comparing five species of Eunice to assess if it was possible to delimitate them by shape variables. The morphology of E. fucata, E. insularis, E. cf. ornata, E. rubra, and Eunice sp. was ...