Sieve-type porecanals

Description:


 * [Catalan/Català]:
 * [French/Français]:
 * [German/Deutsch]: siebförmige Porenkanäle
 * [Italian/Italiano]:
 * [Luxembourgish/Lëtzebuergesch]:
 * [Portuguese/Português]:
 * [Russian/русский]:
 * [Spanish/Español]: