In the back room of the new El Coqui Restaurant, in Cambridge, there’s a large tank full of crickets. A closer look reveals four small frogs, green as unripe bananas, clinging to the back of the glass. The large sign outside the restaurant pictures the same type of frog, grinning on a branch. It all comes together when you read the Puerto Rican myth printed on the menu. According to the legend, Ignacio, king of the forest, challenged his animals to a race, promising a great reward to the winner. The tree frogs won, and Ignacio granted them the gift of song. " Now they sing for all of Puerto Rico, singing Coqui (Ko-Kee), " ends the tale.

Frogs’ legs you won’t find on the menu at El Coqui, but traditional Latin dishes you will. The fried plantains ($2.50), warm and salty discs of the banana cousin surrounded in a mild pancake layer, come casually in a plastic red basket. The yuca en escabeche ($3) is a white root, chopped into wedges and soaked in a subtle oil-and-vinegar mix. Think of a soft and stringy potato with the pleasant pungency of a parsnip. The guineos en escabeche ($3.75), a/k/a green-banana marinade, has a completely unexpected flavor. The lightish-brown banana slices resemble chunks of pork — more like flesh than fruit. The marinade makes for a pickled type of taste; forget the sweet softness of the banana you had for breakfast. Accompanied by onions and peppers, these bananas resemble fruit no more than roast beef resembles watermelon. The result is tropical and intriguing.

In the traditional department, the chicken in sauce comes with white rice and beans or golden rice and pigeon peas ($9.25). The chicken melts off the bone and dissolves in your mouth, and something about the flavor brings palm trees into view. On top of the generous serving of rice come four slices of sweet plantains. It’s the banana flavor you’ve been waiting for inside a fried, salty shell. For dessert, try flan ($3.25), the Latin version of crème caramel — a silky custard with suggestions of vanilla, caramel, syrup, and coconut.

Still young, El Coqui seems to be anticipating larger crowds. On a recent Monday night, the two rooms and many tables were nearly empty. A few people came in to pick up take-out. Two big construction-worker types in heavy boots and overalls mulled over the menu. One caught sight of the tank in the back and gave the waitress a quizzical glance. " No, " she said, anticipating his question, " the frogs are not for eating. "

El Coqui, located at 561 Cambridge Street, in Cambridge, is open Monday through Thursday, from 11 a.m. to 9 p.m.; and on Friday and Saturday, until 10 p.m. Call (617) 876-6500.