In September 1950 Dr H. W. Parker of the British Museum (Natural History) kindly sent me a specimen of an ascidian collected by the yacht, Manihine, for identification. This has proved to belong to an unnamed species of the genus Corella, here described as C. halli. The unique type specimen was obtained from dredgings on a shingle bottom at 35 fathoms, 10 miles WSW. of the Casquets in the English Channel, 30 August 1950 (Manihine, Station no. 81).

External features. The animal (Fig. IA) is enclosed in a transparent test, laterally flattened, circular, of 4 mm. diameter and fixed basally to pieces of sand; there is no stalk. The branchial aperture is terminal anteriorly; the atrial aperture is also anterior and dorsal to the branchial aperture. Both apertures are sessile.