It isn't quite like a death in the family, but Christopher Dodge has the sinking feeling that comes when a dear friend is being taken away.

Time has just about run out for Dodge's good and dear friend, the Illinois mud turtle.

For the last two years, the Interior Department and the Monsanto Co., one of the world's largest chemical concerns, have been doing battle over the fate of the Illinois mud turtle.

Interior wanted to list the little turtle as an endangered species and take steps to save it. Monsanto sympathized but didn't like the idea of part of its property in Iowa being put under a "critical habitat" order.

Monsanto, with the help of a couple of U.S. senators, won the battle. The deadline for listing the mud turtle as endangered was July 3, and the turtle didn't make it.

Until 1954, when Dodge, as an undergraduate zoology student at the University of Iowa, identified it, no one had even realized that the Illinois mud turtle had taken up residence in Iowa.

But there it was, albeit in small numbers, populating the ecologically rich sand mounds along the west bank of the Mississippi River.

Monsanto also populates the west bank of the Mississippi, with a cotton herbicide plant near Muscatine. The mud turtle and Monsanto happen to populate some of the same sandy terrain.

The proposal by Interior's Fish and Wildlife Service two years ago to put the Illinois mud turtle on the endangered list set off another of those great rumbles between industry and government.

According to the Endangered Species Act, these rumbles are supposed to be settled on their merits. But sometimes the merits are better understood when a U.S. senator gets involved.

Monsanto put more than $500,000 into a study of the merits, finding that there were more Illinois mud turtles arund the sand mounds than Interior was saying there were.

The chemical company also got some help from Sens. John C. Danforth (R-Mo.) and Roger W.JEPSEN (R-Iowa), who this year wrote to Interior Secretary Cecil D. Andrus, urging careful review of Monsanto's findings.

"We got letters from Congress. The Office of Management and Budget at the White House called to inquire. Monsanto met with Fish and Wildlife officials. You can believe there was politics in this," said an Interior Department source.

The decision not to list the mud turtle as endangered was made by Len Greenwalt, Fish and Wildlife Service director, after three lower-level endangered-species officers refused to write the order revoking the listing proposal.

One of those who refused, C. Kenneth Dodd Jr., a herpetologist, said he did so because "there was more than sufficient data to make this an endangered-species listing."

Dodd was fired by Andrus last year over another endangered-species matter.

Dodd had committed the affront of chiding a Washington restaurant operator for serving a type of rattlesnake that seemed imperiled. The restaurant, Dominique's, was one of Andrus' preferred luncheon spots. Dodd was rehired when the secretary came back from orbit.

Rattlesnakes aside, as the Illinois mud turtle flap grew, Christopher Dodge sat on the sidelines at the Library of Congress, where he works, and tried to do what he could to help his good friend.

"I feel very proprietary about the Illinois mud turtle, although I'm not what you would call a wild-eyed environmentalist," Dodge said.

"My ploy over the last several years has been to try to make the best out of a rotten situation. Monsanto was trying to prevent another federal bureaucracy from imposing itself over their property -- and one can sympathize. bAnd they have made a very sincere effort to maintain a refuge for the little beast."

But Dodge said he found it "kind of disgraceful" that no one could come up with assurances that would protect the Illinois mud turtle forever.

"There was a solid political front in favor of the Monsanto position," he said. "I am more than a little discouraged."

The Illinois mud turtle's chances of survival are "not too high," in Dodge's view. Other turtle populations (in Illinois, and Missouri) are so small, he said that "the chances of its long-time survival are very slim."

"The last frontier has arrived. The big sand mounds are the last gasp for a species like that."