* Gas-directed rig count steady for second week * Gas rig count just above 18-year low * Horizontal rigs rise after two straight declines NEW YORK, May 31 (Reuters) - The number of rigs drilling for natural gas in the United States was unchanged for a second straight week, hovering just four rigs above the 18-year low posted three weeks ago, data from Houston-based Baker Hughes Inc showed on Friday. The gas-directed rig count stood at 354 for a third week after sinking to 350 during the week ended May 10, its lowest since June 1995. Producers have mostly been curbing dry-gas drilling in favor of more profitable oil and liquids-rich plays such as Eagle Ford in Texas and Marcellus in Appalachia. But gas prices, which hit a 21-month high of $4.444 per million British thermal units a month ago, stirred concerns that producer hedging at higher price levels could keep dry gas output flowing. Prices this week have fallen back toward the $4 per mmBtu level. The oil-focused rig count rose eight to 1,410, after sliding two weeks in a row. The count hit an eight-month high of 1,412 three weeks ago. Baker Hughes also reported horizontal rigs, the type often used to extract oil or gas from shale, rose two to 1,089, after also falling for two straight weeks. Gas futures prices, which were up slightly on the day, in the $4.04 per mmBtu area just before the data was released, slid slightly into negative territory following its release.