"More people missing, I guess." in this paragraph “Talia went first, and read a wonderful poem she'd written about Langston Hughes, and taught us some of his style and about the Harlem Renaissance. I knew she'd wanted to do someone from Samoa, but there weren't any in our textbook. More people missing, I guess. I told her she could find a world-changing Samoan for next semester's presentation, and I thought it was pretty smart of Ms. Trepky to make us look outside the textbook for people to study.” "More people missing, I guess." in this paragraph doesn't seem to make any sense to me. It is a pun that I don't get? It will be really nice of you if you can tell me why the author says that.