From Wikimedia.
Princess Elizaveta may be wearing a lace headdress for this portrait. Her dress has a vee-shaped over bodice called "revers" in the following keywords. In a limited way, her bodice recalls bows en échelle.
Keywords: 1853, Perignon - Alexis Joseph, Elizaveta A. Bariatinskaia, Tchernicheva family, Bariatinsky family, Princess, long straight coiffure, ribbon headdress, off shoulder vee neckline, modesty piece, quarter length tight sleeves, ruching, revers, stomacher, bows, vee waistline, full skirt, flounces, necklace, earrings, bracelets, fan