Shell hemispherical, smooth, with small subregular, circular pores. Collar septum with four large pores (fig. 10_a_). Twelve to fifteen feet, divergent, lamellar, truncate, about as long as the shell. (Similar to certain forms of _Gorgospyris_, Pl. 87, figs. 1 to 3, but with simple shell cavity, without sagittal ring and constriction, and without a columella.) _Dimensions._--Shell 0.08 long, 0.04 broad; feet 0.03 to 0.04 long. _Habitat._--North Pacific, Station 244, depth 2900 fathoms. 2. _Archiphæna corona_, n. sp. Shell crown-shaped, somewhat broader than long, at the base flattened, papillate, with irregular roundish pores. Twenty to twenty-five feet, broad, lamellar, truncate, nearly vertical, about twice as long as the shell. _Dimensions._--Shell 0.1 long, 0.12 broad; feet 0.2 to 0.22 long. _Habitat._--Central Pacific, Station 268, depth 2900 fathoms. Subgenus 2. _Stephanophæna_, Haeckel, 1881, Prodromus, p. 429. _Definition._--Feet branched or forked. 3. _Archiphæna stephanoma_, n. sp. Shell campanulate, somewhat longer than broad, with subregular, circular pores. Margin of the flattened base with a corona of about twenty unequal feet, which are partly simple, partly irregularly branched, and about as long as the shell. _Dimensions._--Shell 0.11 long, 0.03 broad; feet 0.08 to 0.12 long. _Habitat._--Central Pacific, Station 271, depth 2425 fathoms. Family LXI. #CYRTOCALPIDA#, n. fam. Archicorida et Archicapsida, Haeckel, 1881, Prodromus, pp. 427, 428. _Definition._--#Monocyrtida# eradiata. (#Cyrtoidea# with a simple, not jointed shell, representing a simple cephalis without radial apophyses.) The family #Cyrtocalpida#, composed of the Archicorida and Archicapsida of my {1179}Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is quite simple, without transverse constriction, and without radial apophyses. The two subfamilies differ in the shape of the basal mouth, which in the Archicorida is a simple wide opening, but in the Archicapsida is closed by a lattice-plate. Only a few species of this family were formerly known. Ehrenberg, in 1838, founded upon these the genus _Cornutella_, one of the three oldest genera of Polycystina (_Cornutella_, _Lithocampe_, _Haliomma_). In 1862 I described some living forms, with a central capsule, as _Cyrtocalpis_. The Challenger collection contains a large number of new genera and species.