Marine catalogues call it a "motor well boot". I suggest you contact the Parker factory or your local dealer. They shold be able to get a duplicate for you.
yep motor boot. very e-z to replace. I do rec' that you replace as serves to keep wash out and gather hoses, cabels together and protect from any possible chafe. remove old and when replacing with new ,you may want to run some sealant around the base and any screw holes.