Sentence:  Four dogs with intact <WSD>tentoriums</WSD> survived 6 weeks and 8 with sectioned <WSD>tentoriums</WSD> survived the same period of time. 
Meaning of the word marked with <WSD> tags:  The tentorium cerebelli, an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.