Parmal pores regular quadrangular, of nearly equal size and form, six to eight on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores on the two edges of the latter. Spines linear, little compressed, or nearly needle-shaped, very long and thin, their outer half five to ten times as long as the inner.
Dimensions.—Length of the shell 0.11 to 0.12, breadth 0.07 to 0.08; breadth of the spines 0.002.
Habitat.—Mediterranean (Messina), surface.
5. Phatnaspis cristata, n. sp. (Pl. [136], fig. 6).
Parmal pores circular, of very different size, separated by high square crests, ten to twelve on each side of the high, comb-like, primary diagonal rib, which arises from both flat sides of the twoedged spines; two primary aspinal pores on the two edges of the latter. Each circular pore is surrounded by a square frame. Spines sword-like, strongly compressed, their outer part longer than the inner.
Dimensions.—Length of the shell 0.2 to 0.22, breadth 0.16 to 0.18; basal breadth of the spines 0.01.
Habitat.—North Pacific, Station 254, surface.
6. Phatnaspis coscinoides, n. sp.
Parmal pores circular, regular, all of nearly equal size, twelve to sixteen on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary pores on the two edges of the latter. Spines linear, little compressed, their outer part much longer than the inner.
Dimensions.—Length of the shell 0.18, breadth 0.15; breadth of the spines 0.006.