In the course of work on liquid rare earth metals the authors encountered a puzzling problem regarding the ratio of specific heats of liquid La, Ce, Pr and Nd. The purpose of this paper is to comment on this problem in terms of a collective coordinate method applied to liquid 3d transition metals. It is shown that the ratio of specific heats of liquid Nd is definitely larger than 1.1, whereas those of liquid La, Ce and Pr are smaller than 1.1 in contrast to those of liquid alkali, polyvalent and 3d transition metals.