1192 



THE VOYAGE OF 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 012 to 015 long, 01 to 012 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, 

 hexagonaUy framed, twice as broad as the bars. Basal plate with nine cortinar pores (three 

 larger alternating with three pairs of smaller pores, as in PI. 87, fig. 2). 



Dimensions. — Shell 014 long, 0"09 broad. 



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



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



Definition. — C y r t o i d e a 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 thi^ee Families and six Subfamilies of Dicyrtida. 



i Mouth open, . . . . .1. Sethopilida. 



Family LXII. 



Tripocyrtida. 

 Three radial apophyses. 



Family LXIIL 



AntliocyrtiJa. 

 Numerous radial apophyse.s. 



Family LXIV. 



Sethocyrtida. 

 No radial apophyses. 



( Mouth closed, 

 Mouth open, 

 Mouth closed, 

 i Mouth open, 

 ( Mouth closed, 



2. Sethoperida. 



3. Sethophormida. 



4. Sethophaenida. 

 .5. Sethocorida. 



6. Sethocapsida. 



Family LXII. Tripocyrtida, n. fam. 



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



Definition. — D i c y r t i d a triradiata. (Cyrtoidea with a two-jointed shell, 

 divided by a transverse constriction into cephalis and thorax, and bearing three radial 

 apophyses.) 



