Family: Bursidae. The common name Frog Shell comes from the knobby sculpture of most species, which resembles the warty skin of some frogs. This small family group of 30 species lives in tropical or warm seas and features a thick and heavy shell. Frog shells are close relatives of Tritons and have some similar characteristics. The female is usually larger than the male. Most of the species live under coral and consume marine worms. Their egg capsules attach to rock or coral.