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Eucyrtidium hexastichum
(Haeckel, 1887)
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Description - Add description
Benson, 1983, p. 503; pl. 9, figs. 9-11:
Eucyrtidium(?) hexastichum (Haeckel) group
Remarks. Members of this Eucyrtidium-like group are similar in shape to E. hexagonatum and posses the indistinct vertical tubule. They differ by having pores aligned transversely, not longitudinally. Because these forms have a lateral cephalic vertical tube and pores arranged in transverse rows, they would qualify for inclusion in the subfamily Artostrobiinae Riedel of the family Artostrobiidae Riedel emend. Foreman (Nigrini, 1977, p. 243), except that they have only four instead of six collar pores.
In the Gulf of California two general forms of this group are present. One has larger pores arranged in three to five transverse rows per abdominal segment (Benson, 1966, pl. 34, figs. 13-14; this chapter, pl. 9, fig. 10). The other has smaller pores arranged in eight to twelve rows per segment (Benson, 1966, pl. 34, figs. 15-16; this chapter, pl. 9, figs. 9, 11). The latter, as well as tests with pores of intermediate size, are less abundant in the Gulf sediments than are the former.
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