Definition.—Stichophormida (vel Stichocyrtida multiradiata aperta) with ovate or spindle-shaped shell, without lateral ribs. Mouth constricted, with a corona of terminal feet.
The genus Cyrtophormis may be derived from the preceding Artophormis by reduction of the lateral ribs, whilst the terminal feet (as their free prolongations) remain, and form a corona around the mouth. Sometimes also each constriction bears a corona of spines. It corresponds to Calocyclas among the Tricyrtida and Anthocyrtis among the Dicyrtida.
Subgenus 1. Cyrtophormium, Haeckel.
Definition.—Shell with six (sometimes five or seven) feet on the peristome (three perradial alternate with three interradial).
1. Cyrtophormis armata, n. sp. (Pl. [78], fig. 17).
Shell spiny, spindle-shaped, with three annular septa. Length of the four joints = 3 : 4 : 5 : 6. The third joint is the broadest, being twice as broad as the constricted mouth. Pores irregular, roundish. Cephalis conical, armed with a bunch of strong, conical spines, and distinguished by double-contoured pores. Peristome with six (sometimes five or seven) triangular, vertical, parallel, or slightly divergent feet.
Dimensions.—Length of the shell (with four joints) 0.18, breadth 0.09. Length of the single joints, a 0.03, b 0.04, c 0.05, d 0.06.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
2. Cyrtophormis ovata, n. sp.
Shell rough, ovate, very thick-walled, with three distinct strictures. Length of the four joints = 1 : 1 : 2 : 3. The fourth joint is the broadest, inversely hemispherical, and three times as broad as the constricted mouth. Pores regular, circular, hexagonally framed. Cephalis hemispherical, with a pyramidal horn of the same length. Peristome with a coronal of six short, conical, curved, outwardly convex teeth.