W. A.  Herdman, ?Report on the Tunicata collected during the voyage of H.M.S. Challenger during the years 1873-1876. part 1. Ascidiae simplices.?, Zoological Report on the Challenger Expedition, vol. 6, pp. 1-296, 1882.

W. A.  Herdman, ?Report on the Tunicata collected during the years 1873-1876, Part 2: Ascidiae Compositae?, Zoological Report on the Challenger Expedition, vol. 14, pp. 1-429, 1886.