Page:Scientific results HMS Challenger vol 18 part 1.djvu/1072

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864
THE VOYAGE OF THE H.M.S. CHALLENGER.

as long as the radius of the shell; gradually tapering from its surface towards both ends. By-spines very short and numerous, simple.

Dimensions.—Length of the shell 0.13, breadth 0.11; length of the spines 0.08, basal breadth 0.025.

Habitat.—Central Pacific, Station 271, surface.


4. Belonaspis lanceolata, n. sp.

Parmal pores elliptical, six or eight times as large as the small circular sutural pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines lanceolate, flat, in the distal part needle-shaped, about as long as the diameter of the shell. By-spines very numerous, zigzag, half as long as the shell-radius.

Dimensions.—Length of the shell 0.15 breadth 0.13; length of the spines 0.14, basal breadth 0.03; length of the by-spines 0.04.

Habitat.—North Pacific, Station 235, surface.


5. Belonaspis conifera, n. sp.

Parmal pores kidney-shaped, three or four times as large as the small circular pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines very thick, half as long in the outer conical part as in the inner cylindrical part. By-spines very short, conical.

Dimensions.—Length of the shell 0.2, breadth 0.16; length of the spines 0.05, basal breadth 0.03.

Habitat.—Central Pacific, Station 267, surface.


6. Belonaspis multiforis, n. sp.

Parmal pores circular, of the same size as the circular sutural pores. Each plate surrounded by fifteen to eighteen sutural pores (three on each side). Spines compressed, about as long as the radius. By-spines very numerous, zigzag, half as long as the radius.

Dimensions.—Length of the shell 0.22, breadth 0.18; length of the spines 0.12, basal breadth 0.012; length of the by-spines 0.06.

Habitat.—Equatorial Atlantic, Station 347, surface.


Genus 373. Dictyaspis,[1] n. gen.

Definition.Belonaspida with forty parmal pores (two on each plate), without by-spines, but with a network of prominent crests on the dimply surface.

The genus Dictyaspis repeats among the Belonaspida the characteristic structure of Ceriaspis (among the Dorataspida), by the development of prominent crests forming a

  1. Dictyaspis = Net-shield; δίκτυον, ἀσπίς.