I never said he didn't. I said DARWIN didn't embrace MARX. Obviously Marx must claim that evolutionary theory is compatible with communism because he (Marx) has claimed that his historicist theory is "scientific". Any generally accepted scientific theory must be shown to be compatible with Marx's theory, however much shuck 'n jive and shoe-horning may be required. Of course Marx realized there were problems. He tried to wave them off as being due to the "clumsy English style of [Darwin's] argument," but of course the problems were not with the "style" of Darwin's theory, but with it's substance.
Oh, yeah. Darwin's note to Marx thanking him for Das Kapital. We already discussed this. Darwin is cleary, if politely, dismissing Marx, and in the process shoveling a bit of manure in his general direction, e.g.:
I heartily wish that I was more worthy to receive [your book], by understanding more of the deep and important subject of political Economy.
This is B.S. Darwin DID understand "political Economy." In fact he read many full books on the subject. But he didn't read Marx's book. It still exists in Darwin's library, but only a few pages are cut. (You had to cut the pages in those days or you couldn't read the book.)