SAN FRANCISCO - From the state that popularized purse puppies, drive-thru dog washes and gourmet dog food delivery comes the latest in canine convenience - a company that contracts out dogs by the day to urbanites without the time or space to care for a pet full-time.

Marlena Cervantes, founder of FlexPetz, bristles when people refer to her five-month-old business as a rent-a-pet service. She prefers the term "shared pet ownership," explaining the concept is more akin to a vacation time share or a gym membership than a trip to the video store.

"Our members are responsible in that they realize full-time ownership is not an option for them and would be unfair to the dog," said Cervantes, 32, a behavioral therapist who got the idea while working with pets and autistic children. "It prevents dogs from being adopted and then returned to the shelter by people who realize it wasn't a good fit."

FlexPetz is currently available in Los Angeles and San Diego, where Cervantes lives. She plans to open new locations in San Francisco next month, New York in September and London by the end of the year.

For an annual fee of $99.95, a monthly payment of $49.95 and a per-visit charge of $39.95 a day, (discounted to $24.95 Sunday through Thursday), animal lovers who enroll in FlexPetz get to spend time with a four-legged companion from Cervantes' 10-dog crew of Afghan hounds, Labrador retrievers and Boston terriers.