HANOVER, N.H., May 9--Harvard's 12-game winning streak, longest in its history, finally ended today as Dartmouth defeated the Crimson, 8-5.

Deadlocked 3-2 six and third innings, the Indians blasted relief pitcher Al Yarbro for five hits and six runs in two innings to knock the Crimson out of first place in the Eastern Intercollegiate Baseball League.

It was Harvard's second loss in 16 games and first in EIBL play. The Crimson is now in second place, behind undefeated Army, who will visit Cambridge Friday for a crucial meeting.

The Crimson jumped off to a one run lead in its first time at bat, but starter Dick Garibaldi allowed three walks, a single, and two runs in the bottom of the first. Garibaldi and Indian hurler Dave French then settled down and matched zeroes for five innings.

In the top of the seventh, with Gavin Gilmor on second and two out, coach Norm Shepard sent in Andy Shea to hit for Garibaldi. Shea's tap to second was booted by Stan Ota, allowing Gilmor to score the tying run.

But Yarbro, who was shelled by Broken Friday, did not have it again today. After a single and a talk put two men on, Ota atoned for his error with a drive over the left centerfield fence, 310 feet away.

In the eighth, Jacques Shure's homer, a hit batsman, and two singles scored three more for the Indians. Harvard three more for the Indians. Harvard rallied in the ninth, and with the help of three Dartmouth errors managed to score three times before the threat was extinguished by French.

The Crimson will now have to defeat Army, and Yale on May 19 to gain a tie for the EIBL crown if the Cadets do not lose any other games.