Holden keeps saying he is going to call Jane Gallagher, a girl who used to "practically (live) next door to (him), the summer before last" (Chapter 4). Holden has good memories about Jane, and she is kind of an ideal for him. Jane is a dancer, and she and Holden used to play checkers together; although they weren't exactly a couple, they would sometimes hold hands. Holden thinks of her as a "good girl", and is enraged when Stradlater leads him to suspect that he had sex with her on a date.
Holden actually does try to call Jane a couple of times when he arrives in New York. While he is killing time waiting for Sally Hayes, he "figure(s) maybe "he'd give old Jane a buzz...so (he) went in a phone booth and called her up...the only trouble was, her mother answered the phone, so (he) had to hang up" (Chapter 16). Later, after his meeting with Sally, he tries again, "but her phone didn't answer" so (he) had to hang up" again (Chapter 17). Holden never does connect with Jane.
I don't believe Holden mentions what color his brother Allie's mitt is, although he does say that it had "poems written all over the fingers and the pocket and everywhere...in green ink". Holden says that the mitt was "a left-handed fielder's mitt...and that Allie wrote on it so that "he'd have something to read when he was in the field and nobody was up at bat" (Chapter 4).
Holden always wants to call Jane Gallagher, a friend of his from when he was younger. He lived next door to his family's vacation house. Jane is one of the few people that Holden will admit to liking and that make him happy (other others being his little sister Phoebe and his deceased brother, Allie.) Subconsciously, Holden associates Jane with Allie and happier times. Holden has a strong emotional connection to Jane as well. It seems as though he likes her romantically, but she is only willing or able to love him back as a friend. He never ends up calling her in the book.