WASHINGTON--Axis raiders have blasted at least 500 United Nations merchant ships to the bottom in Atlantic waters since the sneak Jap attack on Pearl Harbor, but the toll has dropped steadily in recent weeks due to improved defenses, an unofficial United Press compilation showed tonight.

The relentless underseas warfare that broke off American shores soon after Dec. 7 thus far has taken the lives of more than 5,000 ecamen of all Allied nations. Some 2,000 were Americans.

The greatest number of attacke, which reached a peak during May and June when more than 174 vessels were sunk, occured off the Atlantic seaboard and in the Caribbean.

WASHINGTON--Chairman Paul V. Mc-Nutt of the War Manpower Commission, disclosed tonight that legislation authorizing the government to place men and women wherever they can best serve the war effort is under "careful study" and that recommendations probably will be made in the "near future."

He told the House Agriculture Committee, which has been investigating the shortage of farm labor, that he believed an act of Congress is necessary to allocate manpower wherever the need is greatest, whether it be on farms, in war plants, or in the armed forces.

"I hope that within the very near future certain recommendations will be made," McNutt said. "This whole problem has been the subject of very careful consideration for several months.