Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
3. Cannopilus calyptra, Haeckel.
Dictyocha heptacanthus, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 208; Mikrogeol., 1854, Taf. xix. fig. 39 (?).
Each pileated piece of the skeleton is a truncated six-sided pyramid, like that of Dictyocha speculum, but distinguished by the reticulation of the upper (smaller) ring, which is divided by six beams into six meshes, lying in the horizontal plane of the upper ring. Six peripheral spines on the corners of the lower ring. (The irregular form, figured by Ehrenberg as Dictyocha heptacanthus, loc. cit., is probably only an individual abnormality with seven peripheral spines, instead of six; similar abnormalities occur also among the regular hexagonal forms which I found in the Tertiary rocks of Caltanisetta (Sicily).
Dimensions.—Diameter of the basal ring 0.05, of the apical ring 0.02.
Habitat.—Fossil in Tertiary deposits of Greece and Sicily.
4. Cannopilus hemisphæricus (Haeckel).
Dictyocha hemisphærica, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 266.
Each pileated piece of the skeleton is nearly hemispherical, with thirteen meshes; six lower and larger meshes in the sides of the truncated six-sided pyramid, seven others in the convex surface of the upper ring (one central with six surrounding it). From the six corners of the lower ring arise six horizontal perradial spines. From the inside of the same ring (probably on the side of the six ascending interradial beams) spring six centripetal teeth.
Dimensions.—Diameter of the basal ring 0.02, of the apical ring 0.01.