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Dictyocoryne profunda Ehrenberg, 1860

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Benson, 1966, p. 225-226; pl. 12, figs. 4-6:

Hymeniastrum koellikeri Haeckel

Euchitonia koellikeri Haeckel, 1862, Die Radiolarien, pp. 511-512, P1. 31, figs. 6, 7.
Hymeniastrum kollikeri Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 530.

Internal structure similar to that of Hymeniastrum euclidis; central region larger, with 5-10 concentric, latticed, discoidal shells; arms with 10-16 concentric rings. Arms much broader proximally than in the preceding species with a much shorter region of narrow breadth; terminations of arms spatulate or lanceolate, coming to a point distally in fully developed forms. Position of arms variable from nearly equally disposed to bilaterally disposed; generally a larger distinct odd arm present. A layered spongy patagium either partially developed, rudimentary, or absent; no specimens were observed with fully developed patagium, but in those with patagium partially developed it showed no increase in its thickness distally.

Measurements; based on 30 specimens from stations 27, 34, 46, 60, 64, 71, and 81: angle A 116░-138░, mean 125░; angle B 87░-122░, mean 109░; angle C 117░-140░, mean 126░; ratio of angle A to B 0.98-1.53, mean 1.15, of angle C to angle B 0.98-1.61, mean 1.16; diameter of outer concentric shell of central region 68-105 Ám; length of odd arm (if not distinguishable an arm was either chosen at random or the arm whose axis bisects angle B was chosen) 65-185 Ám, of each of the two similar arms 62-197 Ám and 64-193 Ám; minimum breadth of odd arm 30-68 Ám, of each of the two similar arms 31-59 Ám and 33-59 mm; maximum breadth of odd arm 53-135 Ám of each of the two similar arms 49-117 Ám and 53-114 Ám; length of base of triangular test 135-411 Ám, of altitude 161-42 Ám.

Remarks. In shape of the arms and size and symmetry of the test this species agrees well with Euchitonia koellikeri Haeckel. Haeckel's illustrations (1862, P1. 31, figs. 6, 7), however, do not show concentric rings within the arms, but this feature is not clearly visible in most specimens. The central region of his species has fewer concentric rings (shells) than the Gulf specimens, but they are likewise difficult to observe in numerous specimens from the Gulf, and, in addition, their number is variable within the species.

Distribution. This species is very rare but cosmopolitan in the Gulf, occurring as far north as station 208. It is absent at stations 95, 115, 136, 151, 191, 192, 203, 206, and 214. Its frequency is slightly greater in the southern Gulf where it occurs at all stations. North of this region it is very rare and has a spotty distribution. As in Hymeniastrum euclidis this species has greater affinity for oceanic waters.
Haeckel reported this species from the Mediterranean Sea near Messina; otherwise, no other record of its occurrence was found. It has not been reported from high latitudes; therefore, it is probably confined to tropical seas.
Benson 1966


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