Unidentified acoel flatworm

Comment from Leslie Harris: Your flatworm is an acoel, family Convolutidae, possibly in the genus Amphiscolops. I haven't been able to get any information on it so this id my uninformed guess based on the size and body shape. I've seen several photographs of this species before. All were taken from Indonesia with the possible exception of one which didn't have a locality attached. It's unusually large for an acoel which tend to be micrograzers and predators. Sorry I can't give you any more info.