appendicularia vs urochord

appendicularia and urochord both are nouns.

Word	Noun	Adjective	Verb	Adverb
appendicularia	Yes	No	No	No
urochord	Yes	No	No	No

As nouns, urochord is a hypernym of appendicularia; that is, urochord is a word with a broader meaning than appendicularia:

appendicularia: free-swimming tadpole-shaped pelagic tunicate resembling larvae of other tunicates
urochord: primitive marine animal having a saclike unsegmented body and a urochord that is conspicuous in the larva

Other hypernyms of appendicularia include tunicate, urochordate.

appendicularia (noun)	urochord (noun)
free-swimming tadpole-shaped pelagic tunicate resembling larvae of other tunicates	a notochord of a larval tunicate typically confined to the caudal region
	primitive marine animal having a saclike unsegmented body and a urochord that is conspicuous in the larva