See Norman, Ann. Nat. Hist. ser. 6, xiii. 1894, p. 113.
Hincks, "Marine Polyzoa" (reprints from Ann. Nat. Hist. 1880-91), Index, p. v. note. (Replacing Rhynchopora, preoccupied for a Brachiopod.)
A form of Lepralia pallasiana, in which a mucro is developed, may be mistaken for Umbonula (see characters given for Lepralia under No. 59).
See Arch. Zool. Exp. 2 ser. vi. 1888, p. 135 (as Delagia), and ibid. x. 1892, p. 594. [See also J. Mar. Biol. Ass. v., 1897-99, p. 51.]
F. S. Conant, Johns Hopkins Univ. Circ. vol. xv. 1896, p. 82.