gallery title does not appear

I’ve created 6 thumbnail galleries to use on my site. 4 of them display the title of the gallery in small caps on the left side of the screen, above the gallery. 2 of them display no title. I do want the title to display on all my galleries, and can see no difference in settings among galleries with displayed titles versus galleries without. Can you tell me what makes a title display or not display? Thank you.