(Gegenbaur, 1855)
Trunk up to 1.4 mm long, moderately elongate (Oikopleura cophocerca 2). Buccal glands large, rounded to rectangular. Gonads adjoining the coil of the gut hemispherically, and protruding dorsally when ripe. Tail with 8 oval subchordal cells in a line, arranged in 2 groups near its tip, musculature broad (Oikopleura cophocerca).