N65

Lithocampe sp.

Lithocampe sp. Nigrini, 1967, p. 87, pl. 8, figs. 6a, b

DESCRIPTION

"Subcylindrical shell, rather rough and thick-walled, consisting of 5-8 segments. Cephalis simple, approximately hemispherical, with subcircular pores and a short needle-like apical horn. Collar structure indistinct. Median bar and vertical spine form a V; primary lateral and dorsal spines continue as ribs in the thoracic wall almost to the lumbar stricture.

"Thorax conical, usually longer than, but sometimes of the same length as, subsequent segments. Pores subcircular, arranged in transverse rows. Lumbar stricture not pronounced.

"Post-thoracic segments cylindrical, of approximately equal length (final segment often longer), each with 4-6 transverse rows of subcircular pores, 9-12 on a half-equator. In complete specimens the last segment narrows sharply to form a constricted mouth. However, the final 1 or 2 segments are often irregular, incomplete specimens in which the shell mouth is ragged and wide open are common." (from Nigrini, 1967).

DIMENSIONS "Total length 128-218 microns. Maximum breadth 54-72 microns" (from Nigrini, 1967).

Plate 24, figures 5a,b N66

RECENT DISTRIBUTION

1. Nigrini, 1967, fig. 46; "Indian Ocean occurrences - L. sp. is sparsely distributed in low latitudes, but is abundant (2% to 16% of the described population) south of 30 degrees S. It appears to be a reliable and potentially useful member of the middle latitude assemblage."

2. Nigrini, 1970, fig. 30 belongs to a transitional assemblage derived by recurrent group analysis of North Pacific samples; has been observed rarely in a few tropical samples.

3. Lozano, 1974, Fig. IV-3; "Maximum abundance of 0.5 percent. Present only in 3 samples west of 5 degrees W with a maximum abundance of 0.3 percent. To the east it is rarely found under subantarctic waters and it is generally present under subtropical waters in proportions varying from 0.1 to 0.5 percent. Found only under waters with February surface temperatures about 15 degrees C in the Atlantic and 12 degrees C in the Indian Oceans."

4. Robertson, 1975; "This species loads most heavily in factor 2 (subtropical). At the present it is absent in the Sea of Okhotsk, Bering Sea, and extreme northern part of the northwest Pacific. With the exception of one sample it is absent north of 40 degrees N at 18,000 YBP."