During the early Silurian, they developed specialized cells, which were lignified (or bore similar chemical compounds) to avoid implosion; this process coincided with cell death, allowing their innards to be emptied and water to be passed through them.
Durante o inicio do Silúrico, desenvolveron células especializadas, que estaban lignificadas (ou tiñan compostos similares á lignina) para evitar a súa implosión; este proceso coincidiu coa morte celular, o que permitiu que o seu interior se baleirase e a auga pasase a través deles.