The LOX dome (aka the "oxidizer dome") is located at the forward end of the engine and routes high-pressure liquid oxygen from the turbopump to the injector, where it is mixed with fuel and subsequently burned.

Here's an exploded-view diagram of the thrust chamber, showing the oxidizer dome and injector:

Click image for a 1562x2120 pixel version of this image in a new window.
From p. 1-7 (p. 22 in the PDF) of F-1 Engine Familiarization Training Manual (R-3896-1) [direct link to 16.8M PDF file at UAH's USSRC Archive]
Extraction and cleanup by heroicrelics.org.

Here's a picture of the forward end of the LOX dome from F-114-2 at Stafford Air & Space:

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Picture by heroicrelics.org.

The only vintage picture or diagram I've been able to find of the aft-facing end of the LOX dome appears below (LOX dome locate in center of the photo).

Taken from Saturn V Quarterly Report No. 16.
Video capture by heroicrelics.org.

F-107-1 at Science Museum Oklahoma (formerly the Omniplex) is displayed without its injector, so the aft-facing side of the LOX dome is visible:

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Picture by heroicrelics.org.

Note the arrangement of larger holes around the periphery of the LOX dome face; compare with the holes in the video capture above; note how the two holes at about the 11:00 position are closer together. Also note the 16 smaller-diameter holes closer to the center of dome face (alternating with the slots). These appear to correspond with the 16 inner dome attach bolts, in both the diagram above and the photo of forward end of the LOX dome above.

Thanks to Vince Wheelock for providing invaluable research and insight into the F-107-1 LOX dome issue.