Hexactinelid or Hexactinellid: How To spell?
The word Hexactinelid is misspelled against Hexactinellid, an adjective meaning "Having six-rayed spicules; belonging to the Hexactinellinae."
Hexactinellid has double "ll" is mispronounced as "l"Remember double 'LL' in between the strings hexactine & id which should not be misspelled with single 'L'
Wrong Spelling:  hexactine-l-id  Correct Spelling:  hexactine-ll-id 
Find more wrongly spelled words of Hexactinellid to spell it well.