both galaxies seem to form a distinct sequence at the very same location in the PLDs as the sequence of fundamental mode pulsators (labeled sequence C; cf. Sect.1) found by various authors for the Magellanic Clouds. For illustration purposes, we overplotted the relations of Ita et al. ([@ita]). To shift their relations according to the difference in distance between the Magellanic Clouds and our galaxies, we adopted the distance moduli determined via the brightness of horizontal branch stars for our target systems by Butler et al. ([@butler]). They derived distance moduli of $(m -
M)_{0}$=$24\fm38\pm 0\fm01$ and $24\fm09\pm0.06$ mag for and , respectively. For the LMC we adopted the distance modulus obtained by Pietrzyńsky et al. ([@pietr]) of $(m - M)_{0}$=$18\fm50\pm 0\fm06$. With respect to the atmospheric chemistry, we find O-rich stars along the whole sequence (with a slight thinning in number towards the top), while C-rich stars mainly occupy the upper part of the sequence. This agrees with findings of other studies (e.g., Wood [@woodc] or Ita et al. [@ita]). After applying a 3.0$\sigma$ clipping to exclude stars that are considered not to belong to sequence C, a least-squares fitting was performed to obtain PLRs for this sample of 