Page:Scientific results HMS Challenger vol 18 part 1.djvu/743

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REPORT ON THE RADIOLARIA
535

9. Euchitonia virchowii, Haeckel.

Euchitonia virchowii, Haeckel, 1862, Monogr. d. Radiol., p. 503, Taf. xxx. figs. 1-4. Histiastrum fasciatum, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 842.

Distance between the paired arms about half as large as their distance from the odd arm, which is somewhat larger. Each arm with six broad chambers, bisected by a radial septum; the terminal chamber convex, blunt, twice as broad as the basal chamber. Patagium incomplete, with concave chamber-rows, enveloping the arms with exception of the broad blunt terminal face.

Dimensions.—Radius of the paired arms 0.15, of the odd arm 0.16; basal breadth 0.05, terminal breadth 0.1 to 0.12.

Habitat.—Mediterranean (Messina), Atlantic (Canary Islands).


Subgenus 2. Pteractis, Ehrenberg, 1872 (loc. cit.).

Definition.—Arms provided with radial spines at the distal end.


10. Euchitonia elegans, Haeckel.

Pteractis elegans, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 299, Taf. viii. fig. 3.

Distance between the paired arms half as large as their distance from the odd arm. This latter is straight, while both the former are concavely curved towards the middle line. Arms five times as long as broad, at the distal end pointed and armed with a short conical terminal spine. Patagium nearly complete, enveloping four-fifths of the arms, with four to five concave chamber-rows.

Dimensions.—Radius of the arms 0.2, breadth of them 0.03.

Habitat.—Tropical Pacific, Philippine Sea, depth 3300 fathoms (Ehrenberg).


11. Euchitonia carcinus, n. sp. (Pl. 43, fig. 10).

Distance between the paired arms scarcely one-fourth as great as their distance from the odd arm. This latter is straight, twice as long as the former, which are concavely curved towards the middle line. The odd arm is three times as broad at the distal end as at the narrow base. The end of each arm is furnished with a strong triangular radial spine and a group of smaller spines. Patagium incomplete, with two to three concave chamber-rows, enveloping only the basal half of the arms.

Dimensions.—Radius of the paired arms 0.15, breadth 0.03; radius of the odd arm 0.3, breadth on its base 0.02, on its distal end 0.07.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.