The word animalcules is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 21
Highest Scoring Words With Friends™ Play In The Letters animalcules
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Seven Letter Word Alert: (42 words)
aclinal, acumens, alliums, alumels, alumina, alumnae, alumnal, amnesia, amnesic, anaemic, animals, caesium, calamus, canulae, canulas, cauline, cinemas, clausal, emulsic, emulsin, encalms, icemans, inulase, lacunae, laminae, laminal, laminas, leucism, macules, malaise, malices, malleus, manacle, maniacs, manilla, manuals, mensual, micella, miscall, musical, seminal, unlaces