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Peripyramis circumtexta Haeckel, 1887

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Peripyramis circumtexta (p. 1162):
Shell slender, pyramidal, with nine strong radial beams, connected by fifteen to twenty transverse horizontal rings, which are partly complete, party interrupted. Meshes subregular, square. From the nodal points of the surface there arise branched spines, which at equal distances from it are connected by thin threads, forming a delicate outer arachnoidal shell with large irregular polygonal meshes.

Dimensions: Shell 0.32 long, 0.16 broad.
Habitat: Central Pacific, Station 271, depth 2425 fathoms.
Haeckel 1887
Benson, 1966, p. 426-427; pl. 29, fig. 4:

Peripyramis circumtexta Haeckel

Peripyramis circumtexta Haeckel, 1887, Challenger Rept., Zool, vol.18, p. 1162, Pl. 54, fig. 5; Riedel, 1958, B.A.N.Z.A.R.E. Repts., ser. B, vol. 6, pt. 10, p. 231, Pl. 2, figs. 8, 9.

Remarks. The Gulf species is not different from the description given by Riedel (1958, p. 231). It differs from Plectopyramis dodecomma Haeckel in that the transverse bars which join the longitudinal thoracic ribs are not continuous around the circumference and in the presence of forked spines arising from the bars of the thorax. The longitudinal thoracic ribs are slightly convex outward whereas in P. dodecomma they are either straignt or slightly concave outward near the basal mouth of the thorax.

Measurernents; based on 3 specimens from stations 27 and 34: maximum length of test 172-208 µm; maximum breadth of thorax 101-116 µm, of outer siliceous network covering thorax 123-148 µm; length of cephalis 12 µm; breadth of cephalis 12-14 µm; length of apical spine 2-6 µm.

Distribution. This species is very rare in the Gulf, occurring only at stations 27, 34, and 46. Riedel (1958, p. 231) states that it may be cosmopolitan in that it occurs in the tropical parts of the Pacific and Indian Oceans as well as in the American and Indian Ocean sectors of Antarctic waters and in the northern Pacific.
Benson 1966











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