Definition.—Tholospyrida without basal feet, with an apical horn.
The genus Pylospyris was first known from a Mediterranean species, called by me, in 1862, Spyridobotrys trinacria. As this name was given erroneously, on the supposition of a near relation to the Botryodea (= Polycyrtida), I changed it afterwards to Pylospyris. This genus differs from the other Tholospyrida in the total absence of basal feet, and may therefore be derived either from them by reduction of the feet, or from Dictyospyris by formation of a galea.
1. Pylospyris denticulata, Haeckel.
Lithopera denticulata, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 297, Taf. xii. II. fig. 7.
Lithobotrys denticulata, Ehrenberg, 1844, Monatsber. d. Akad. Berlin, p. 203.
Shell spinulate, with slight coronal and deep sagittal constriction, with irregular, roundish pores of variable size. Galea hemispherical, about half as long and broad as the nut-shaped cephalis. No symmetrically disposed larger pores.
Dimensions.—Galea 0.04 long, 0.06 broad; cephalis 0.08 long, 0.1 broad.
Habitat.—Antarctic Ocean, Ehrenberg. (Included in the ice.)
2. Pylospyris trinacria, Haeckel.
Spyridobotrys trinacria, Haeckel, 1862, Monogr. d. Radiol., p. 341, Taf. xii. figs. 8, 9.