Monte Carlo simulations in the canonical ensemble were carried out to investigate the dependence of the behavior of ethane and a model system (when molecules are longer than ethane) in the adsorbing slitlike pores on the average density, the force of the adsorption field, and the temperature. In the nearest to the walls adsorbed layers the tendency of ethane to orientational transitions was revealed when the temperature was decreased from 180 to 160 K. There are no orientational transitions in the systems of the molecules longer than ethane. At T = 140 K the orientation of ethane molecules perpendicular to the walls is absolutely preferential.