Kirby Corporation (NYSE:KEX) announced record net earnings for the fourth quarter ended December 31, 2008 of $38.4m, or $.72 per share, compared with net earnings of $34.4m, or $.64 per share, for the 2007 fourth quarter. The 2008 fourth quarter net earnings included a $6m before taxes, or $.07 per share, increase in Kirby's allowance for doubtful accounts. Consolidated revenues for the 2008 fourth quarter were a record $326.7m, an increase of 6% over the $307.9m reported for the 2007 fourth quarter. "While our fourth quarter results mark the 20th consecutive quarter that our net earnings exceeded the same quarter of the previous year…