animalculum vs animalcule

animalculum and animalcule both are nouns.

Word	Noun	Adjective	Verb	Adverb
animalculum	Yes	No	No	No
animalcule	Yes	No	No	No

As nouns, animalculum and animalcule are synonyms defined as:

animalculum and animalcule: microscopic organism such as an amoeba or paramecium

animalculum (noun)	animalcule (noun)
microscopic organism such as an amoeba or paramecium	microscopic organism such as an amoeba or paramecium