When Lassie has trouble giving birth to...

When Lassie has trouble giving birth to her litter during a storm, Jeff hurries to get the vet who is five miles away on “Jeff’s Collie” (Tuesday at 2:30 p.m. on Nickelodeon).

In the first episode with Thelma Lou (Betty Lynn), Andy tells Thelma Lou about Barney’s feelings for her on “The Andy Griffith Show” (Tuesday at 3:35 p.m on TBS).

Mork tells Mindy about his first trip to Earth when he met the Fonz (Henry Winkler) on “Mork & Mindy” (Tuesday at midnight on Nickelodeon). On Wednesday’s episode, Mork remembers his date with Laverne (Penny Marshall).

Ed wants his own bachelor stall at the stables, so he writes Dear Abby for advice on “Mr. Ed” (Wednesday at 5 a.m. on Nickelodeon).

A pre-”Bonanza” Lorne Green guests on “Alfred Hitchcock Presents” (Wednesday at 10:30 p.m on Nickelodeon) in an episode in which a man gets more than he bargained for when he answers a help-wanted ad.

Dennis the Menace (Jay North) visits the Stones and helps Donna redecorate the house as only he can on “The Donna Reed Show” (Thursday at 1:30 a.m. on Nickelodeon).

The Ricardos and the Mertzes go to see the hit Broadway musical “The Most Happy Fella,” which currently is being revived in New York, on “I Love Lucy” (Thursday at 3:05 a.m. on TBS).

When Agarn becomes engaged to a pretty widow whose previous four husbands died mysteriously, O’Rourke tries to switch her affections to the jinxed soldier, Wrongo Starr (Henry Gibson) on “F Troop” (Saturday at 11:30 a.m. on Nickelodeon).

C’est si bon! Eartha Kitt guests on “The Nat King Cole Show” (Saturday at 9 p.m. on KOCE).

Jon Provost, sans Lassie, guests on “Mr. Ed” (Saturday at 11:30 a.m. on Nickelodeon) in episode in which he pitches for Wilbur’s Little League baseball team.