The genus Attheya T. West consist of small single celled diatoms. Some of these species were earlier regarded to belong to Chaetoceros, or to Gonioceros, the taxonomic status of some of these species are still debated.
They are distinguished morphologically from Chaetoceros by the structure of valve outgrowths or girdle bands. The girdle bands can only be seen with an electron microscope. Resting spores are seldom observed. Vegetative cells tend to attach to different substrates, including other diatoms, and are sometimes referred to as epiphytic. However, they are also observed to be planktonic.