GENUS LEUCALTIS HAECKEL, 1872

Type species: Leucaltis clathria Haeckel, 1872 (subsequent designation by Dendy & Row, 1913).

Diagnosis: The same as that of the family.

Synonyms: Artynas – Haeckel, 1872: 405; Heteropegma – Poléjaeff, 1883: 25; Dendy, 1913: 17; Dendy & Row, 1913: 737; Leucaltis – Haeckel, 1872: 142; Dendy & Row, 1913: 737; Borojević & Peixinho, 1976: 1002; Borojević et al., 1990: 258; 2002: 1147; Lévi, 1998: 75; Wörheide & Hooper, 1999: 877; Borojević & Klautau, 2000: 190; Klautau et al., 2013: 454; Leucaltusa – Haeckel, 1872: 143; Leucetta – Poléjaeff, 1883: 28; Leucettusa – present study.

Remarks: The body of Leucaltis species is formed by tubes that anastomose in most parts. Each tube is covered with cortex and atrium with endopinacoderm. Even though the body wall of Leucaltis includes cortical, choanosomal and atrial skeletons, it is thin.

It is important to highlight that the choanosomal and atrial spicules of Leucaltis are much smaller than the cortical ones. They are mostly cylindrical, thin and frequently become sagittal at the excurrent canals and at the atrial surface.

Scope: Three species of Leucaltis are currently accepted: L. clathria Haeckel, 1872; L. nodusgordii (Poléjaeff, 1883) and L. tenuis Hôzawa, 1929, but we propose the transference of three other species to this genus: Clathrina latitubulata Carter, 1886, Leucettusa corticata (Haeckel, 1872) and Leucettusa sambucus (Preiwisch, 1904) .