A study examined the effects of prior knowledge and the explicitness of text connectivity on various measures of reading ability. Subjects were 130 eighth grade students who read 6 prose passages that had been manipulated for content familiarity and for use of explicit connectives and implied connectives (those brought about by the author's arrangement of sentences). Forty-one multiple choice test items accompanied each passage. The findings indicated that the familiarity of the content of a passage is an important variable to consider when studying comprehension. In addition, the more able readers appeared to exhibit more sensitivity to disruptions in the connectivity of the passages than did the less able readers, and their sensitivity was evident in both familiar and unfamiliar passages. (Copies of the passages and multiple choice questions used in the study are appended.) (FL)