sutural pores much larger than the coronal pores, which are very small and very numerous (fifty to sixty on each plate). Sutures sinuate. Radial spines compressed, outer and inner half nearly of equal length.
Dimensions.—Diameter of the shell 0.3, aspinal and sutural pores 0.01 to 0.015, coronal pores 0.001 to 0.002.
Habitat.—Tropical Atlantic, Station 338, surface.
5. Coscinaspsis polypora, n. sp. (Pl. 136, fig. 8).
Shell very thin walled, with smooth surface, without crests and dimples, the two aspinal pores of each plate narrow, lanceolate, ten to twelve times as long as broad and half as long as the radius of each plate. Coronal pores irregular, polygonal, very numerous (two hundred to three hundred on each plate), commonly arranged more or less regularly in ten to twelve series parallel to the longitudinal diameter of the aspinal spines (ten to twenty pores in each series). Sutural pores irregular, polygonal, very numerous. Radial spines very thin and long, cylindrical.
Dimensions.—Diameter of the shell 0.24; length of the aspinal pores 0.04, breadth 0.004; coronal and sutural pores 0.002 to 0.01.
Habitat.—Tropical Atlantic, Station 349, surface.
6. Coscinaspis orthopora, n. sp.
Shell very thin walled, with smooth surface, without crest and dimples. All pores of nearly equal size and form; quadrangular, mostly rectangular; one hundred to two hundred, separated by two systems of parallel bars, perpendicular one to another, occur in each plate. Sutural pores mostly triangular. Radial spines very thin and long, cylindrical, somewhat compressed. (Similar to those of Phatnaspis lacunaria, Pl. 136, fig. 9, but spherical, not ellipsoidal.)
Dimensions.—Diameter of the shell 0.2, pores 0.008 to 0.012.
Habitat.—Central Pacific, Station 272, surface.
7. Coscinaspis parmipora, n. sp. (Pl. 137, fig. 9).
Shell thin walled, with smooth surface, without crests and dimples. There are no sutural pores, since all twenty plates are connected by perfect sinuate sutures (therefore this excellent species may perhaps better represent a peculiar genus, called by me in 1866 Craniaspis). All pores are parmal pores; each plate with two elliptical aspinal pores, which are twice to five times broader than the numerous, roundish irregularly scattered coronal pores (thirty to fifty occurring on each plate). The radial spines are quite internal, that is, not prolonged on the outside of the shell; in this respect they resemble those of Sphærocapsa.
Dimensions.—Diameter of the shell 0.16, aspinal pores 0.01, coronal pores 0.002 to 0.005.
Habitat.—North Atlantic, Canary Islands (Lanzerote), surface.
