Thank you for all the information on entails. I was just reading Domestic Realities and Imperials Fictions: Jane Austen's Novels in Eighteenth-Century Contexts by Maaja A. Stewart, specifically Chapter Two (Wit and Knowledge of the World: Pride and Prejudice).

On page 53, Stewart is talking about how a foolish character such as Mrs Bennet can still (occasionally) speak a truth, such as questioning the arbitrary distribution of wealth and power in society.

"The careless attitude toward securing the futures of females in a society where those futures could only be secured with inheritance or marriage is marked by the fact that Mrs. Bennet's father, a lawyer, did not insist during the marriage settlement that the entail should be broken, as it could so easily have been." [emphasis mine]