Aspects of the crystallization history of the primitive crust of the HED (howardites, eucrites, diogenites) achondrite parent body have been deciphered from the microtextures and chemical compositions of pyroxene and plagioclase in some Antarctic HED achondrites intermediate to diogenite and eucrite. Five new specimens related to Yamato 75032 and three eucritic clasts in Y791186 and Y791208 have been investigated by electron microprobe, analytical transmission electron microscope, and X ray diffraction techniques. Their pyroxene compositions cover the entire range from Fe-rich diogenite to eucrite. The pyroxene textures of the Y75032-type achondrites indicate that many of them crystallized as low-Ca pigeonite, and some as orthopyroxene. Later shock events modified the original inversion and exsolution textures. The chemical compositions and the interstitial occurrence of plagioclase crystals in pyroxene indicate crystallization from intercumulus trapped liquid. The pyroxene crystallization and the relation between the anorthite content (An) of plagioclase and the Mg/(Mg+Fe) number of the coexisting pyroxene in these specimens reveal two crystallization trends: One trend is intermediate to that of the Mg-rich suites of the lunar highland crust and that of ferroan anorthosite, and the other is a trend with a steep decrease in the An content, while the Mg/(Mg+Fe) of the pyroxene remains effectively constant. A model involving crystal fractionation in a shallow magma ocean or intrusion in the parent body has been proposed.