N37

Dictyophimus infabricatus Nigrini

Dictyophimus infabricatus Nigrini, 1968, p. 56, pl. 1, fig. 6

DESCRIPTION

"Shell thin-walled, smooth, conical to inflated conical. Cephalis simple, spherical, with numerical small subcircular pores. Apical horn usually 1 to 2 times the cephalic length (rarely longer), either 3-bladed or cylindrical) vertical horn present, usually shorter than apical horn, but sometimes equally developed. Both apical and vertical spines free of shell wall. Thin by-spines present on cephalic and upper thorax. Collar stricture distinct.

"Thorax tetrahedral with 3 strong, 3-bladed or cylindrical ribs, corresponding to primary lateral and dorsal spines; ribs either divergent or bowed, tapering distally, and extending beyond the thoracic lattice, which is usually attached to the ribs for its entire length. Pores subcircular to subangular, aligned longitudinally and increasing in size distally. Termination invariably ragged." (from Nigrini, 1968).

DIMENSIONS "Length of cephalis 14-27 mu, of thorax 72-156 mu, of ribs 127-230 mu. Maximum breadth of cephalis 18-27 mu, of thorax 72-156 mu." (from Nigrini, 1968).

Plate 22, figure 5

N38

RECENT DISTRIBUTION

1. Nigrini, 1968, text-fig. 7, "Few along the coast of Central and South America, except from 0 ° to 10 ° N; rare or absent in all other samples examined."

2. Molina-Cruz, 1975, Code N24; used in factor analysis of southeast Pacific assemblages; cf.Appendix 10 for percent N24 at each station. It is not certain whether or not Molina-Cruz's concept of the species is the same as that of Nigrini (1968) or if he includes forms ascribed by Moore (1974) to the species, but described herein as Pterocanium sp.