1) Coelenterate genus 2) Genus sertularia 
• (n.) A genus of delicate branching hydroids having small sessile hydrothecae along the sides of the branches.
Ser`tu·la'ri·a noun [ New Latin , dim. from Latin serta a garland.] (Zoology) A genus of delicate branching hydroids having small sessile hydrothecæ along the sides of the branches. 
Sertularia is a member of the order Calyptoblastea.
[n] - sessile hydroid that forms feathery colonies
genus Sertularia noun sessile hydroid that forms feathery colonies