Henri Van Heurck examined a sample collection of sea ice and underlying sea floor sediment material during the Belgian Antarctic Expedition (1897–1899). He described eight new taxa of the monoraphid diatom genus Cocconeis from this collection including: C. antiqua var. tenuistriata, C. gautierii var. gautierii and var. inornata, C. heydrichii, C. japonica var. antarctica, C. litigiosa, C. schuettii var. schuettii and var. minor. All these Cocconeis taxa share well-silicified sternum valves with wide, apical hyaline areas, more or less lenticular in shape, and narrow hyaline bands at mid-distance between the apical axis and the margin, while the more delicate raphe-sternum valves bear uniseriate striae, a hemistauros associated with the central raphe area, and crescentshaped terminal hyaline areas. Since their original description in the early 20th century, these Cocconeis taxa have been rarely reported. I studied newly described Cocconeis taxa from Van Heurck’s type material by light microscopy. The main valve features of C. gautierii var. gautierii and var. inornata, C. litigiosa, and C. schuettii var. schuettii and var. minor agree well with those of Cocconeis antiqua; I propose these five taxa be reduced to synonymy of C. antiqua.