Who actually delivers Gatsby's eulogy at the funeral in The Great Gatsby?Why did Fitzgerald find it necessary to add this particular part into the...

The only other thing that I can think to add to this is the fact that Nick's final remarks act as a eulogy of sorts for Gatsby.

Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eluded us then, but that’s no matter—to-morrow we will run faster, stretch out our arms farther. . . . And one fine morning——

So we beat on, boats against the current, borne back ceaselessly into the past.

In essence, this is Nick's eulogy for Gatsby. A eulogy does not have to be delivered at the funeral. It is generally a text of some sort (it can be a poem, even) that honors the dead. In this case, the entire novel is a eulogy as well, an extended honoring of Jat Gatz his one true friend, Nick Carraway.