Definition.—Sethophormida (vel Dicyrtida multiradiata aperta) without thoracic ribs, with numerous terminal feet around the mouth (twelve to fifteen or more). Cephalis free, with an apical horn.
The genus Anthocyrtium has been derived from the two preceding genera by further multiplication of the terminal feet, the number of which is at least twelve to fifteen, often twenty or more. It may be that some species have arisen directly from Patagospyris by loss of the sagittal ring.
Subgenus 1. Anthocyrtarium, Haeckel.
Definition.—Feet of the peristome-corona divergent, their basal distance less than their terminal distance.
1. Anthocyrtium chrysanthemum, n. sp. (Pl. [62], fig. 14).
Shell smooth, with distinct collar stricture. Length of the two joints = 3 : 7, breadth = 4 : 9. Cephalis hemispherical, with small, circular pores, and a large, straight, cylindro-conical horn, about as long as the shell. Thorax campanulate, hemispherical, with six to eight transverse rows of squarish pores, increasing in size downwards. Mouth little constricted, with twelve to fifteen divergent, curved, slender feet, about as long as the thorax.
Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.07 long, 0.09 broad.
Habitat.—Central Pacific, Station 270 to 274, depth 2350 to 2925 fathoms.
2. Anthocyrtium centaurea, Haeckel.
Anthocyrtis mespilus, var. major, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. vi. fig. 5.