[7] In 1961 Ryder was cast as Eli Wallach's first replacement as Bérenger (a role originated in London by Olivier) in the Broadway production of Eugène Ionesco's Rhinoceros.

[15]) Nevertheless, Ryder remained an A-list television guest star throughout the 1960's, as his eccentric, theatrical style and vaguely Germanic accent were well-suited for the sci-fi, spy, and fantasy shows that were popular at the time.

He appeared in "The Man Trap", the first-aired episode of Star Trek, on September 8, 1966, as a scientist who is hiding the fact that a shapeshifting alien is masquerading as his late wife.

He also guest-starred as the ghost of a World War I German U-boat captain in two episodes of Irwin Allen's ABC-TV series Voyage to the Bottom of the Sea.

[17] By the 1970s, Ryder's credits (and billing) had diminished, with his last significant role coming in 1979, on Steve Allen's PBS faux-talk show Meeting of Minds, for which he also co-directed two episodes.

[18] Despite an energetic performance as Machiavelli with extensive dialogue, Ryder only appeared once more onscreen, as restaurateur Mike Romanoff in the 1980 Humphrey Bogart TV-biopic Bogie.

[19] In his later years Ryder lived with his sister, actress Olive Deering, eventually moving to the Actors Home in New Jersey, where he died of liver cancer in 1995.