Length 4-28 mm. P V much longer than P VI and VII (Themisto gaudichaudi 1). Dactyls of P V-VII smooth. Pereon segments VI and VII and pleon segments I and II with more or less developed dorsal spines. P V with long, lanceolate ART 5, very long (longer than ART 5), straight, narrow ART 6. In adult females ANT II longer than ANT I. Epimeral plates with sharp posterodistal corners. Very common in Antarctic waters. Active predators.