Sentence:  The first or most anterior <WSD>anfractuosity</WSD> on the superior surface of the brain is longitudinal, and being the continuation and termination of the principal one on the inferior surface, it extends a very short distance from before backwards. 
Meaning of the word marked with <WSD> tags:  One of the fissures (sulci) separating the convolutions of the brain, or, by analogy, in the mind.