Page:Scientific results HMS Challenger vol 18 part 2.djvu/105

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Definition.—Basal ring with three descending feet (one caudal and two pectoral).

3. Podocoronis cortiniscus, n. sp. (Pl. 97, fig. 2).

Basal ring violin-shaped, with three straight divergent thorny feet, about as long as the ovate sagittal ring. The dorsal part of the latter is straight, vertical, and prolonged downwards into the caudal foot, upwards into a stout, thorny, vertical apical horn. The ventral part is semicircular and gives off the lateral branches, forming the kidney-shaped sagittal ring. All the rings and their apophyses are armed with stout thorns. This and the following tripodal species may be directly derived from Cortina.

Dimensions.—Height of the frontal ring 0.1, breadth 0.15.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.

4. Podocoronis tripodiscus, n. sp.

Basal ring kidney-shaped, with three large divergent curved feet, nearly twice as long as the semicircular sagittal ring. The straight dorsal part of the latter is prolonged downwards into the caudal foot, upwards into a large branched apical horn, curved backwards. Differs from the preceding species mainly in the longer curved apophyses and in the larger violin-shaped frontal ring.

Dimensions.—Height of the frontal ring 0.12, breadth 0.2.

Habitat.—North Pacific, Station 238, surface. Fossil in Barbados.

Definition.—Basal ring with four descending feet (two sagittal and two lateral).

5. Podocoronis tetrapodiscus, n. sp.

Basal ring kidney-shaped, with four stout and straight divergent feet, about as long as the sagittal ring; two of them are lateral and arise from the basal corners of the violin-shaped frontal ring (at its junction with the basal ring); two are sagittal, and arise from the basal corners of the semicircular sagittal ring (one posterior caudal and one anterior sternal). The straight dorsal part of the sagittal ring is prolonged upwards into an apical horn. All the rings are thorny.

Dimensions.—Height of the frontal ring 0.15, breadth 0.25.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

Definition.—Basal ring with six radial descending feet (two sagittal, two pectoral, and two tergal feet).