“Shark Tank” (9 p.m., ABC): Cue the “Jaws” theme song. On “Shark

“Shark Tank” (9 p.m., ABC): Cue the “Jaws” theme song. On “Shark Tank,” a feeding frenzy occurs when three of the tycoons sink their teeth into an Internet company concept presented by two brothers.

“Masterpiece Mystery!” (9 p.m., PBS): On another installment of “Masterpiece Mystery!,” Inspector Lewis (Kevin Whatley) investigates the death of a prominent Oxford Don and finds himself drawn into the world of illegal, no-rules boxing.