Sentence:  The morphology of the scolex, particularly the <WSD>rostellum</WSD>, is also useful in diagnosis; "T.[Taenia] saginata" has no <WSD>rostellum</WSD> and its scolex bears no hooks, making it easily distinguishable from "T. solium", which has an armed <WSD>rostellum</WSD>. 
Meaning of the word marked with <WSD> tags:  A retractable protruding part at the anterior end of a soft-bodied tapeworm; the scolex from which it protrudes is often armed with hooks which serve to keep it in place attached to the host.