Synonyms for Bulbous (same or very similar meaning)
WordNet sense 1 (shaped like a bulb):
bulblike, bulb-shapedWordNet sense 2 (having a circular shape):
circular, roundWordNet sense 3 (curving outward):
bulgy, protuberant, bulging, bellied, bellyingWordNet sense 4 (thrusting outward):
protrusiveFrom the ODE community, based on WordNetadd/edit