Hex·ac`ti·nel'line adjective [ From New Latin Hexactinellinæ , from Greek 'e`x six + a dim. of ..., ..., a ray.] (Zoology) Belonging to the Hexactinellinæ , a group of sponges, having six-rayed siliceous spicules. Found on http://www.encyclo.co.uk/webster/H/41