Notes sobre el desenvolupament embrionari dels cargols d'aigua dolça "Physa acuta" i "P. fontinalis" (Gasteròpodes, Pulmonats)

Autors/ores

  • Joan-Antoni Vela i Fernàndez

Resum

The development of two species of Physids (Physa acuta and P. Fontinalis) is studied. On the whole they agree with the early description given by Wierzejski, though our study adds two points worth considering. Firstly, there is a clear asymmetry in the dorsal half of the trochophore as shown by the shell gland displacement to the right and further by the fact that cell Id22 is placed higher than lc22 in the dorsal region of the head vesicle. The possible mechanisms leading to both asymetries are discussed. Secondly, the invaginating shell gland and radular sac are the RNA richest tissues in the trochophore. The possible relationships between cell differentiation pathway and this RNA endowment are discussed for both tissues. Finally, in the species studied, there is a clear relationship between the enteroblasts and the gut wall during the development of the hindgut. This result is clearly at variance with Wierzejski's description.

Descàrregues

Publicat

2005-05-17

Número

Secció

Articles