Description
Test fragile , brittle , basically plate-like and typically discoidal but sometimes folded into more complex shapes. Circular apertures developed along margin in some species. External xenophyae firmly cemented to form upper and lower plates ; internal xenophyae sparse , commonly forming pillar or bar-like structures between plates. Granellare branches and well-developed stercomare strings run between plates and branch around pillars . Occurrence : Northeast Atlantic , equatorial and west Pacific , 1158-6059 m. irregularly circular in shape , measuring 1 2- 1 5 mm in diameter and 0 .6-1.4 mm thick. Edge either swol len or tapered and perforated by smal l circular apertures . Upper and lower plates also have small , scattered pores. Plates easily detached, revealing yellowish granellare strands and dark , radially organized , sometimes anastomosing stercomare masses. Occasional connecting pi II a r s occur between plates . Xenophyae mainly radiolarian tests . Other species: P. globigerina Haeckel , 1889 ; P. plakina Haeckel , 1889 ; P. delicata Gooday & Tendal , 1988, P. fusca Gooday & T endal , 1988, P. sabulosa Gooday & T endal , 1 9 8 8 . 1 0 91 Several large undescribed species with folded morphologies occur in the east Pacific (Fig . 7) . Refs. Schulze (1906) ; Tendal (1972; in press) ; Gooday and Tendal (1988).
Type species
Psammina nummulina Haeckel , 1889 (Fig .6) : Test light grey, very brittle and
Figures
Raw text
Test fragile , brittle , basically plate-like and typically discoidal but sometimes folded into more complex shapes. Circular apertures developed along margin in some species. External xenophyae firmly cemented to form upper and lower plates ; internal xenophyae sparse , commonly forming pillar or bar-like structures between plates. Granellare branches and well-developed stercomare strings run between plates and branch around pillars . Occurrence : Northeast Atlantic , equatorial and west Pacific , 1158-6059 m. irregularly circular in shape , measuring 1 2- 1 5 mm in diameter and 0 .6-1.4 mm thick. Edge either swol len or tapered and perforated by smal l circular apertures . Upper and lower plates also have small , scattered pores. Plates easily detached, revealing yellowish granellare strands and dark , radially organized , sometimes anastomosing stercomare masses. Occasional connecting pi II a r s occur between plates . Xenophyae mainly radiolarian tests . Other species: P. globigerina Haeckel , 1889 ; P. plakina Haeckel , 1889 ; P. delicata Gooday & Tendal , 1988, P. fusca Gooday & T endal , 1988, P. sabulosa Gooday & T endal , 1 9 8 8 . 1 0 91 Several large undescribed species with folded morphologies occur in the east Pacific (Fig . 7) . Refs. Schulze (1906) ; Tendal (1972; in press) ; Gooday and Tendal (1988).