S21

Siphonosphaera polysiphonia Haeckel

Siphonosphaera polysiphonia Haeckel, 1887, p. 106; Nigrini, 1967, p. 18, pl. 1, figs. 4a, b.

DESCRIPTION "Shell spherical, rather thick-walled with somewhat rough or pitted surface and numerous small subcircular pores, irregularly scattered. Four to ten poreless tubules, thin-walled, cylindrical, having no definite arrangement. Tubules usually as long as broad, about 0.2 shell radius, but may be longer, up to 0.25 shell radius; smoothly truncated tangentially, or sometimes obliquely to the sphere." (from Nigrini, 1967).

DIMENSIONS "Diameter of shell 81-119mu. Maximum length of tubules 9-27mu; their maximum breadth 9-18mu." (from Nigrini, 1967).

REMARKS

1. Benson's (1966) description and dimensions of this species (Siphonosphaera cf. socialis Haeckel in Benson, p. 121) are consistent with the above.

Plate 1, figures 6a,b

S22

RECENT DISTRIBUTION

1. Benson, 1966 (Siphonosphaera cf. socialis); "...appears to be a tropical oceanic form. In the Gulf [of California]. It is very rare... It is apparently not influenced by upwelling."

2. Nigrini, 1967, fig. 5; "Indian Ocean occurrences - S. polysiphonia is rather sparsely distributed in low latitudes and is practically absent from middle latitude samples. Maximum abundance occurs in a sample near Africa (SERPENT (?) 9, 10% of the described population)."

3. Molina-Cruz, 1975, Code S37; used in factor analysis of southeast Pacific assemblages; cf. Appendix 10 for percent S37 at each station.

4. Morley, 1977, fig. 1-6; "This species loads highest in factor 4 (subtropical). At present it is most abundant in central and western South Atlantic subtropical and tropical waters and absent south of 40degS. It is difficult to determine the difference in abundance between 18,000 YBP and today because of the absence of samples at the 18,000 year level in the region where this species is presently most common."