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DescriptionBenson, 1966, p. 324-326; pl. 22, figs. 19-21: Ceratospyris cf. pentagona Ehrenberg ?Ceratospyris pentagona Ehrenberg, 1872a, Akad. Berlin, Moriatsb. (1872), p. 303; 1872b, Akad. Berlin, Abhandl. (1872), Pl. 10, fig. 15. The structure and shape of the collar ring, collar pores, and sagittal ring are the same as in Ceratospyris polygona. Seven foot-like spines, conical to three-bladed, correspond to those of C. polygona but are generally shorter. Major differences between this species and C. polygona are: (1) the presence of thinner intervening bars of the cephalis that are generally circular in section with none or only a few three-bladed; (2) the presence of fewer but larger pores of the cephalis; (3 ) the presence of two pairs of very large polygonal pores, each pair separated by the sagittal ring, on the dorsal face of the cephalis, these pores being much larger than those of C. polygona; the bars separating the lower from the upper pair on the dorsal face are absent or rudimentary in several specimens; therefore, in these forms only one pair of large sagittal pores are present; (4) in many tests the presence of only one pair of large, polygonal sagittal pores on the ventral face of the cephalis; (5) the straight not convex upward outline of the upper surface of each lobe of the cephalis; this is represented by heavy, straight bars originating from the base of the apical spine on its right and left and corresponding to those of C. polygona, occupying the upper dorsal edge of the cephalis; the bars extend laterally and are either horizontal or ascend at a small angle and continue as thin conical spines; the bars extend nearly to the lateral limits of the bi-lobed cephalis in contrast to the short bars of C. polygona; a pair of similar bars are present in most specimens at the upper ventral edge of the cephalis; (6) the presence of few, if any, spines arising from the surface of the cephalis; and (7) a smaller, less variable maximum breadth of the cephalis. Measurements; based on 25 specimens from stations 71 and 133: sagittal height of cephalis 47-68 µm, maximum breadth 73-98 µm; length of feet 5-23 µm, of apical spine 0-36 µm, of vertical spine 5-15 µm. Remarks. Ehrenbergs illustration of Ceratospyris pentagona (1872b, Pl.10, fig. 15) is similar to the Gulf species in the lack of three-bladed bars and the presence of short spines or feet. His drawing lacks details, however, and the feet are not differentiated from the surface spines. The presence of pentagonal pores may not be of specific value, although the sagittal pores of the Gulf species are generally pentagonal. Distribution. This species is rare in the Gulf but occurs as far north as station 191. It is present but rare at stations 34, 46, 81, 92, 93, 106, 115, 133, 136, 151, and 191. Its absence and rare occurrence in the southern half of the Gulf but its greater frequency at stations located in the diatomite facies of the northern Gulf indicates that it responds to upwelling there. Its generally rare occurrence indicates its little affinity for Gulf waters. Ehrenberg (1872a, p. 303) reported C. pentagona from the Indian Ocean near Zanzibar. Haeckel (1887, p.1067) later reported this species as cosmopolitan, occurring at the surface of the Atlantic, Pacific, and Indian Oceans. Due to the uncertain identification of the Gulf species, nothing can be stated about its world-wide distribution except that it is present in the eastern tropical Pacific.