Page:Scientific results HMS Challenger vol 18 part 2.djvu/336

1212 holes, and below the prominent distal end by a broad, triangular, roundish ring of subregular lattice-work (with square pores). Peristome smooth, about half as broad as the thorax.

Dimensions.—Cephalis 0.04 long, 0.04 broad; thorax 0.08 long, 0.1 broad.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

Definition.—Horn of the cephalis fenestrated. Peristome on the margin of the basal mouth with a corona of spines.

5. Clathrocanium diadema, n. sp. (Pl. 64, fig. 2).

Clathrocorona diadema, Haeckel, 1881, Prodromus, p. 431.

Cephalis hemispherical, thorny, with irregular roundish pores, and a large prismatic horn of twice the length, the three edges of which are denticulate and fenestrated, each with a series of square pores. Length of the two joints = 1 : 3, breadth = 2 : 4. Thorax thorny, with three broad fenestrated divergent ribs, which are separated by three large ovate holes (twice as long as the cephalis) and have their prominent distal ends connected below by a broad circular ring of lattice-work (with irregular polygonal small meshes). Peristome wide, two-thirds as broad as the thorax, with a circular corona of small square pores and alternating prominent small teeth.

Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.07 long, 0.09 broad.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

6. Clathrocanium reginæ, n. sp. (Pl. 64, fig. 4).

Clathrocorona reginæ, Haeckel, 1881, Prodromus, p. 431.

Cephalis hemispherical, with irregular roundish pores and a prismatic club-shaped horn of twice the length, the three edges of which are denticulate and fenestrated. Length of the two joints = 1 : 3, breadth = 1 : 4. Thorax thorny, with three broad triangular, fenestrated and nodulated ribs, which are separated by three large ovate holes (twice as long as the cephalis) and have their prominent distal ends connected below by a circular ring of lattice-work. Peristome constricted, as broad as the thorax, with a corona of short spines.

Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.08 long, 0.12 broad.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.

Definition.— (vel Dicyrtida triradiata aperta) with three divergent lateral ribs in the wall of the flat, conical, discoidal, or pyramidal thorax. Cephalis with a horn. Peristome smooth, without corona of spines.