Welcome to Law.com Class Actions: Critical Mass, a weekly briefing for class action and mass tort attorneys.

This week: Another Roundup trial began in Philadelphia, while Monsanto has challenged last month's $175 million verdict. The manufacturer of Chicco KidFit booster seats plans to oppose its own settlement on Wednesday, citing fraud in the claims process. Find out who represents a group of defendants, including Oakley, in new antitrust cases involving prescription glasses and sunglasses.