New York’s tony private schools are suffering a sudden drop in class sizes, but not in a good way. So many parents are short of cash because of the credit squeeze and layoffs from Wall Street, they are having to do the unthinkable: remove their children from school, reports Victoria Goldman, author of The Manhattan Family Guide to Private Schools, in New York magazine. At 300-year-old Trinity on the Upper West Side, fees $31,000 a year, 45 families have given notice their kids won’t return next year, and some parents who previously paid in full are asking for financial aid. The same is happening at Horace Mann, too, which charges the same fees as Trinity. And schools are expecting things to get worse. “The hardest thing,” says Goldman, “will be for admissions directors to figure out which new applicants will be able to stay the course.”