Page:Scientific results HMS Challenger vol 18 part 2.djvu/341

Rh The genus Callimitra, and the two following nearly allied genera, Clathromitra and Clathrocorys, form together a peculiar small group, the Callimitrida, living in the Central Pacific, and differing from the other Sethopilida in some remarkable points, derived perhaps directly from the Archiscenida, Archiscenium and Pteroscenium, by the development of thoracic network between the three cortinar feet. In the centre of the collar septum, where these feet are united, there arises a vertical free columella, prolonged over the top of the cephalis as a free horn, and this horn is connected with the three thoracic ribs by three vertical fenestrated wings.

1. Callimitra carolotæ, n. sp. (Pl. 63, figs. 1, 7, 8).

Cephalis campanulate, conical, with irregular, polygonal pores, and a thin bristle-shaped apical horn of the same length. Length of the two joints = 3 : 6, breadth = 2 : 6. Thorax in the upper half with irregular network, in the lower half with parallel transverse bars; in each of its three sides descend two convergent pairs of stronger, parallel, curved ribs, not confluent at the peristome. Each of the three vertical wings with eight stronger ribs, three arising from the cephalis, five from each foot. Dedicated to my dear mother Charlotte Sethe.

Dimensions.—Cephalis 0.07 long, 0.05 broad; thorax 0.15 long, 0.15 broad.

Habitat.—Central Pacific, Station 270, depth 2925 fathoms.

2. Callimitra annæ, n. sp. (Pl. 63, fig. 2).

Cephalis campanulate, conical, with irregular, polygonal pores, and a thin bristle-shaped horn of the same length. Length of the two joints = 1 : 2, breadth = 1 : 3. Thorax nearly in its whole extent with parallel transverse bars, which are crossed by two convergent systems of parallel beams; in each of its three sides descend four convergent pairs of stronger, parallel, curved ribs, not confluent at the peristome. Each of the three vertical wings with six stronger ribs, three arising from the cephalis, three from each foot. Dedicated to my dear first wife Anna Sethe.

Dimensions.—Cephalis 0.05 long, 0.05 broad; thorax 0.12 long, 0.18 broad.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

3. Callimitra agnesæ, n. sp. (Pl. 63, fig. 5).

Cephalis pear-shaped, with irregular, square pores, and a slender bristle-shaped horn twice as long. Length of the two joints = 1 : 3, breadth = 1 : 5. Thorax in its whole extent with parallel transverse bars, which are crossed by two converging and crossed systems of parallel beams; in each of its three sides descend five convergent pairs of stronger, parallel, curved ribs, the two or three upper of which are crossed at the peristome. Each of the three vertical wings with five stronger ribs, three arising from the cephalis and the horn, two from each foot. Dedicated to my dear second wife Agnes Huschke.

Dimensions.—Cephalis 0.05 long, 0.05 broad; thorax 0.15 long, 0.22 broad.

Habitat.—Central Pacific, Station 273, depth 2350 fathoms.