An eastern horseplayer who visits Santa Anita may sometimes think he needs an interpreter when he converses with the locals. I was certainly confused when I heard one of the resident experts saying, "The favorite might be a lone F, but he looks like a lobster, so I'm going to baseball three longshots."

In California lingo, a speed horse who figures to get loose on the lead is a "lone F." (A speed horse with no stamina is quaintly described as having "lick but no stick.") An animal who is not being bet as heavily as he should--whom easterners would describe as being "dead on the board"--is a "lobster" here, for reasons which are etymologically obscure. It is also unclear why a horseplayer who goes to the window to box numbers 2, 4 and 6 in the exacta will say, "Baseball the 2, 4, 6."

I thought I had mastered most of the local terminology until a bettor named William Murray expressed the opinion that a particular horse here was a "dead crab." At first I thought this was an off-the-cuff insult--as people sometimes term a bad horse a pig or a roach or a beetle--but then Murray went to the window to bet the animal. A dead crab, he explained, is a sure thing.

Because Murray is a professional writer, the author of a forthcoming racetrack novel called "The Million-Dollar Move," he was able to offer a thorough etymological exegesis of the term.

"I have two friends, Harold and Joe, who are a couple horse degenerates," Murray said, "but six years ago they were losing and were tired of the track. So they decided to take a safari to Africa. After two weeks of going to game parks, though, all they could think about was getting back to Del Mar. On the last night of their trip, they were sitting in their hotel in Nairobi when they heard a commotion in the courtyard. They looked out and saw one guy setting up a blackboard and another carrying a big basket of crabs--all of whom had numbers on their backs."

Crab racing! Harold and Joe wasted no time learning how the game was played. The crabs were placed under a net in the middle of a ring. When the net was lifted, they all started moving, since the instinct of a crab is to scuttle to safety. Sometimes, as a variation, beer bottles or other obstacles were placed in the ring--crab racing's equivalent of steeplechasing.

Harold and Joe lost all their $2 bets up to the last race, which offered a form of exotic wagering. The bookmaker would pay a flat 5 to 1 to anybody who could pick the last-place finisher. Harold sipped his gin and tonic, studied the entrants and then whispered to Joe, "I think No. 7 is dead." The two of them watched intently for five minutes, and didn't see No. 7 move so much as an antenna. "I think you're right," Joe said. They bet $20.

The crab was dead, and they won their bet. "And that," Murray concluded, "is why a sure thing is called a dead crab."