Morris has scored 22 tries this year and is the only player to score 100 points from tries alone in one season in the four-year history of the Highlanders First XV competition.
Otago Boys' goal kicker Sam Ellis leads the competition in scoring with 112 points, followed by Morris on 110.
Otago Boys' scored 12 tries against a determined Menzies side that made the competition leader work hard to score points.
Mobile hooker Ryan Williams scored two tries and was the best Otago Boys' forward. Towering lock Josh Dickson dominated the lineout and made ground with the ball in hand.
John McGlashan College midfield back Markis Schaaf also reached a significant milestone on Saturday when he became the first player in the Highlanders First XV competition to play 50 games.
Fullback Chris O'Connell kicked a penalty after seven minutes in the second spell to give McGlashan a narrow 3-0 win over Dunstan High School in Dunedin.
McGlashan's solid defence kept its line intact in the final 20 minutes.
Halfback Ed Davies, No 8 Cameron Wood, flanker Ollie Reid and hooker Sam Pringle had strong games.
Waitaki Boys' High School retained its unbeaten record when it scored seven tries to beat South Otago 41-7 in Balclutha.
The midfield pair of Levi Fogarty and Anthony Wetere-Sweet weaved their magic on attack and Fogarty scored two tries.
Waitaki was prepared to attack from all parts of the paddock, and both backs and forwards were dangerous with the ball.
Mobile lock Dan Lolo ran like a back with the ball and was backed by hooker Tui Katoa, who scored two tries. Flanker Jake Rhodes was dominant at the breakdown.
Waitaki and Otago Boys', the only unbeaten teams this year, will meet in a midweek showdown next week.
In other games, Gore High School beat Kavanagh College 40-7 in Gore, and St Kevin's College beat James Hargest High School 22-10 in Invercargill.
Southland Boys' High School beat King's High School 57-5 in a midweek game in Invercargill.
