Dimensions.—Diameter of the irregular cortical shell 0.12 to 0.18; length of the lentelliptical medullary shell 0.05 to 0.06, breadth 0.035 to 0.045.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, &c., common, surface and in various depths.
2. Phorticium spironium, n. sp.
Cortical shell irregular, roundish, tuberous, about four times as large as the enclosed subregular Larnacilla-shell, connected with it by some irregular radial beams, and by opposite, spirally begining, irregularly latticed girdles, comparable to those of Spironium; between them remain six to twelve large open gates of irregular size and form. Surface rough. The resemblance to some forms of Spironium makes it probable that this species is a deformity or monstrosity of that genus.
Dimensions.—Diameter of the irregular cortical shell 0.12 to 0.2, of the lentelliptical medullary shell 0.03 to 0.06.
Habitat.—Pacific, central area, Stations 270 to 274, surface, and in various depths.
Subgenus 2. Phortolarcus, Haeckel.
Definition.—Lattice-work of the irregular cortical shell complete, without large openings or gates.
3. Phorticium deforme, n. sp.
Cortical shell irregular, roundish or longish, three times as large as the enclosed subregular, lentelliptical Larnacilla-shell, connected with it by two opposite latticed wings (the halves of the transverse girdle of Tetrapyle). Network of the cortical shell irregular, dense, perfectly closed, without larger openings or gates. Surface thorny. (May be regarded as a monstrous form of Larnacalpis.)