27. Shibaev et al.6,7 have reported that PCAn(n=5,10) and PCMAn(n=5,10) form the smectic phases in wide range of temperatures and the cholesteric phases are observed in a narrow temperature range. In contrast with these results, PCA10 and PCA5 have been reported to form only a smectic phase by Hattori et al.13 and by Kaneko et al.,14 respectively. PCMAn(n=1-5,7,9-11,15) have been also reported to form only smectic phases by Yamaguchi et al.9 and by Yusa et al..17 The origin of this difference remains unanswered.