A 13-year-old Severn girl, who was bitten late Tuesday afternoon by what officials believe was a shark while swimming off the North Carolina coast, was released from the hospital yesterday and is expected to recover.

Alexis Huesgen was about three feet into the surf off the resort town of Carolina Beach when she felt something snap at her right arm about 5:30 p.m., officials said. Alexis ran toward her parents, who wrapped her injured arm in a beach towel. Their cell phones did not work, so they drove to a convenience store to get help, officials said.

Store cashier Tammy Young said yesterday that a man burst through the front door and said to call 911 because "we've just had a little girl bitten by a shark."

Young said she dialed on a mobile phone and ran outside, where she could see the teenager in the back seat of a silver station wagon, huddled between family members and looking scared but not crying.

Doctors at the New Hanover Regional Medical Center operated for three hours on the lacerations and torn tendons that stretched from Alexis's elbow to her fingers, said surgeon Dennis Nicks, according to a transcript of a news conference.

Witnesses told police they had seen a shark in the area where she was swimming, but authorities were not sure what bit Alexis, calling it only an "unidentified sea creature."

Jack Musick, a shark expert at the Virginia Institute of Marine Science in Gloucester County, said shark bites are "pretty rare." But he added, "There are not many other things it could have been this time of year."

About a dozen shark attacks have occurred this year in the United States, said George H. Burgess, curator of the International Shark Attack File at the Florida Museum of Natural History.

Seven attacks were in the Atlantic Ocean off the Florida coast, three were in the Gulf of Mexico, one was off the California coast and two were in Hawaii, he said.

There have been 25 reported shark attacks -- four of them fatal -- in North Carolina since officials began compiling statistics.

Musick said most shark attacks occur when smaller species of sharks are trolling for food in shallow waters.

"In the surf, the sand is stirred up," he said, "and they get a glimpse of an elbow or a hand or a foot as they're swimming by. And they reflexively snap at it."

Alexis left the hospital yesterday with her arm bandaged and in a sling, hospital spokeswoman Kendra Gerlach said. The girl's parents, Timothy and Stephanie Huesgen, thanked the doctors and said in a statement that "this is a happy ending to a scary story."

The family plans to continue its vacation in North Carolina for one more week before returning to Maryland, Gerlach said.

Meanwhile, additional life guards have been on duty since the incident, said Valita Quattlebaum, spokeswoman for Carolina Beach.

Beachgoers "are being cautious," she said, but "most have decided to go back in the water."

Alexis Huesgen, with her parents Stephanie, rear, and Timothy Huesgen, is wheeled from New Hanover Regional Medical Center after her surgery.