Diagnosis. Shell small, whitish, without colour pattern; slightly wider than high; whorls rounded, without shoulder; sculptured by close set spiral lirae, not corded; axial sculpture of sub-sutural and umbilical pliculae.
Description. Shell small, turbiniform, height moderate (L/D = 0.77-0.89); whorls evenly rounded and lacking shoulder; suture slightly sunken; periphery at mid-whorl; protoconch large and globose, diameter 600-800 (im; teleoconch of up to three whorls. Sculpture of spiral lirae and axial pliculae; spiral lirae begin at start of teleoconch, approx. 10 on first whorl (only visible in freshest shells) becoming more numerous in later whorls as intermediaries develop; lirae similar on base and in umbilicus. Axial sculpture of close set sub-sutural pliculae starting near beginning of second whorl; pliculae obsolete toward periphery but reappear on base near umbilicus. Umbilicus deep, relatively narrow but expanding rapidly; margin evenly rounded, pliculate. Aperture almost circular, peristome virtually complete; outer lip prosocline, smooth; interior not obviously nacreous. Colour: White, translucent, dark colour of visceral mass shows through apex of live-taken specimens. Dimensions: Largest specimen, diameter 4.7 mm. length 3.6 mm
Radula (Herbert 1987c: fig. 183): Rachidian and inner laterals broader than in other local forms, similar to those of S. philippense; outer lateral long and slender; latero-marginal plate short. External anatomy: As in S. pardalis, mantle cavity dark brown.

With its rounded whorl profile, close-set spiral liration and large protoconch, Spectamen martensi is most similar to S. multistriatum (Thiele, 1925). That species, however, is larger and lacks axial pliculae. The large protoconch suggests that, like several other South African species of Spectamen, this taxon broods its developing larvae in the mantle cavity (Herbert 1987c).

South-Africa: Southern KwaZulu-Natal (off Melville) to E. Cape (off Waterfall Bluff), 300-420 m (living 380-420 m).