Behind the quick and easy vote to extend the Endangered Species Act this week was a kind of byplay not often seen in the House of Representatives.

The alligator gambit, in which a congressman from the Louisana bayour country tried quietly to punish a federal regulatory body, has left some House members muttering bitterly to themselves.

It involves a delicate question about the mutual trust with which the legislators operate: Did Rep. John B. Breaux (D-La.), mislead the House Rules Committee to get permission to take his alligator-inspired amendment to the floor?

Breaux's answer is that no, he absolutely did not mislead the committee when he said his amendment was only "minor" and "technical" and had full support of the Merchant Marine and Fisheries Committee.

At his side that day last month was Rep. John M. Murphy (D-N.Y.), chairman of the Merchant Marine panel, who joined in Breaux's insistence that the amendement was a little consequence.

But some House members and invironmentalists are furious with Breaux, accusing him of distorting facts so he could punish regulators who were impeding the lucrative trade in alligator hides from the Lousiana swamps.

One legislator who was concerned was Rep. Anthony C. Bellenson (D-Calif.), a Rules Committee member. He said he felt the amendment could have serious international treaty repercussions, and objected to it, but was overruled.

"I thought Rules was being taken advantage of," Beilenson recalled this week. "I don't think we were being deceived, but we definitely thought the amendments had gone through Merchant Marine and Fisheries. I felt a major change was being proposed, stemming from an argument over alligators. I don't like legislating that way."

Aides to other House members, who declinded to be quoted by name, had similar theories. "We felt Mr. Breaux was less than candid in making his amendment appear minor," said one. Commented another: "We didn't appreciate it at all. Breaux just didn't contact committee members who might have opposed his amendment."

After the Rules Committee gave Breaux and Murphy a rule that would permit no challenges to the amendment on the floor, these points came to light: p

Neither Breaux's subcommitee nor Murphy's full committee had held formal hearings or debate on the disputed amendment. Committee extension of the act, without the amendment, occurred in May. Breaux came up with his proposal after a later oversight hearing unrelated to the bill itself.

The State Department said the Breaux amendment would put the United States in violation of the worldwide Convention on International Trade in Endangered Species (CITIES) by seriously restricing the independence of the regulatory panel.

White House lobbyists interpreted Breaux's proposal similarly and worked furiously to get him to alter it to conform to CITIES after Rules had approved the amendment.

But while Breaux bowed to pressure, modifying his amendment somewhat, he achieved his basic aim reducing the independence of the Endangered Species Scientific Authority (ESSA) by putting it under control of the secretary of the interior.

The House approved that approach Wednesday when, by voice vote, it aggreed to extend the Endangered Species Act for three more years. A Senate-approved version leaves ESSA's independence intact, to the issue will be decided by conferees chosen to work out the differences.

But the action by Breaux, chairman of the subcommittee that oversees the endangered species law, has left a trail of bad feeling.

"What gravely concerns us," said Lewis Regenstein, executive vice president of the Fund for Animals, "is the committee using very underhanded and mendacious tactics to try to cripple and abrogate a treaty to which the United States is a party."

Added Faith Campbell of the Natural Resources Defense Council: "That is not the way to legislate. The ESSA issue was not dealt with by the Breaux subcommittee. We agreed not to fight him on the floor because we couldn't win and we needed him to fight off other crippling amendments -- of which he kept reminding us."

Beilenson and eight other House members on Oct. 19 voted against the rule considering the species law, with its prohibition on challenges to Breaux. The rule was adopted, 320 to 99. The nine included Reps. David E. Bonior (D-Mich.), Don Bonker (D-Wash.), Michael E. Lowry (D-Wash.), Edward J. Stack (D-Fla.) and Gerry E. Studds (D-Mass.) Merchant Marine and Fisheries members who were angered by the Breaux-Murphy representations.

Breaux insisted in an interview that he had hidden nothing from the Rules Committee and that his proposal had the concurrence of Merchant Marines and Fisheries.

But he conceded that he was deeply distrubed by an ESSA action that had prevented alligator traders in his district from selling hides to France and Japan. ESSA held that the Louisiana alligators -- although not on the endangered list -- might be confused with imperiled corocodilians and should not be sold to those countries.

"The made a political decision and they could get away with it because they were answerable to no one. We caught them on it," Breaux said. "The American alligator is plentiful and the export of hides would not hurt."

Breaux said that between 10,000 and 15,000 alligators, whose hides are sold for about $20 a foot, were harvested in his district last year. The income is important to the district because trapping is "a lifestyle for many people."

Environmentalists fear that ESSA, created as an independent body by a 1973 presidental executive order, could be subject to intense political pressure as an element of the Interior Department.