Page:Scientific results HMS Challenger vol 18 part 2.djvu/316

This page has been proofread, but needs to be validated.
1192
THE VOYAGE OF THE H.M.S. CHALLENGER.

2. Archicapsa quadriforis, n. sp.

Shell ovate, rough, a little longer than broad. Pores subregular, circular, twice as broad as the bars. Basal plate with four larger ovate cortinar pores (two smaller jugular and two larger cardinal pores).

Dimensions.—Shell 0.12 to 0.15 long, 0.1 to 0.12 broad.

Habitat.—Central Pacific, Station 265 to 268, depth 2700 to 2900 fathoms.


3. Archicapsa nonaforis, n. sp.

Shell pear-shaped, thorny, one and a half times as long as broad. Pores regular, circular, small, hexagonally framed, twice as broad as the bars. Basal plate with nine cortinar pores (three larger alternating with three pairs of smaller pores, as in Pl. 87, fig. 2).

Dimensions.—Shell 0.14 long, 0.09 broad.

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




Section II. DICYRTIDA, Haeckel, 1862, Monogr. d. Radiol., pp. 280, 296.

Definition.Cyrtoidea dithalamia, with two-jointed shell, being divided by a transverse collar stricture into an apical joint (or cephalis) and a basal joint (or thorax).

Synopsis of the three Families and six Subfamilies of Dicyrtida.


Family LXII. Tripocyrtida.

Three radial apophyses.

Mouth open, 1. Sethopilida.
Mouth closed, 2. Sethoperida.
Family LXIII. Anthocyrtida.

Numerous radial apophyses.

Mouth open, 3. Sethophormida.
Mouth closed, 4. Sethophænida.
Family LXIV. Sethocyrtida.

No radial apophyses.

Mouth open, 5. Sethocorida.
Mouth closed, 6. Sethocapsida.



Family LXII. Tripocyrtida, n. fam.

Sethopilida et Sethoperida, Haeckel, 1881, Prodromus, pp. 431, 433.

Definition.Dicyrtida triradiata. (Cyrtoidea with a two-jointed shell, divided by a transverse constriction into cephalis and thorax, and bearing three radial apophyses.)