A Calliostoma having a very prominent spiral sculpture dominated by three primary cords; the uppermost one is about twice the size of the two others. The apical whorls have axial ribs giving the shell a cancellate sculpture. The abapical whorls have a fine spiral sculpture and a fine axial sculpture.
Description. — The shell consists of nearly nine whorls, including the well preserved protoconch. It is conical in outline with an apical angle of about 700 and a slightly convex base. The aperture is rounded rectangular in shape, oblique, forming an angle of about 400 with the shell axis. The parietal wall is slightly arched and has a reflected callus which completely covers the umbilicus. The shell is thin, semitransparent and whitish with irregular dark patches, particularly at the periphery and the base. It is nacreous, particularly at the inner surface. The teleoconch forms about eight whorls and is dominated by a prominent spiral sculpture, while the protoconch is without any sculpture.
The spiral sculpture is dominated by three primary cords. Only the two uppermost cords are completely visible on the whole of the teleoconch. The lowermost cord is located at the lower suture, and it is completely hidden on the apical whorls by the growth of the successive part of the shell. From the fourth whorl on it becomes partly visible, but it is not completely visible until the body whorl. The uppermost primary cord is considerably larger than the two lower ones and is located a little below the central part of the whorl. A much less distinct secondary cord appears at the third whorl of the teleoconch, and this cord gradually becomes more prominent. At the fifth whorl another secondary cord is added between the upper suture and the secondary cord just referred to. This cord gradually becomes more prominent than the secondary cord just mentioned. In addition there is a fine spiral striation both on the primary and secondary cords and in the interstices between them. The body whorl has about eleven threads on the apical part between the primary cord and the two secondary cords. Between the uppermost and the central primary cord there are six threads. In addition both the primary and the secondary cords have spiral threads. On the body whorl the uppermost primary cord has seven threads, while the other primary cords and the secondary cords have four to five.
The axial sculpture: the apical whorls of the teleoconch have prominent, oblique ribs which become much less distinct on the abapical part of the whorl between the second primary cord and the lower suture. The spiral and axial sculptures give the three apical whorls a distinct cancellate appearance with well developed nodules at the junctions. The axial ribs become reduced towards the base of the shell, developing into an irregular close-set striation. The nodules both at the primary and the secondary cords persist and become divided into several individual nodules corresponding to the number of spiral threads on the cords.
The base of the shell has two prominent spiral cords near the periphery. A finer spiral sculpture consists of flat bands separated by narrow interstices. The spiral sculpture of the base, which consists of some 30 bands, gradually becomes coarser towards the umbilicus. One rounded spiral cord originates from the apical part of the parietal wall and two adjacent cords a little further down.
Dimensions in mm: height, 32.0; breadth, 29.0; height of body whorl, 18.4; height of aperture, 10.0.

The type of the genus Calliostoma is C. zizyphinum (Linnaeus, 1758) (see Clench & Turner, i960: 11). The species occurs in shallow water in the northeast Atlantic from northern Norway (Finmark) to the Canary Islands as well as in the Mediterranean, C. altena differs from C. zizyphinum in the following respects: (1) C. altena has a much more delicate shell. (2) In C. zizyphinum the body whorl has five or six flattened spiral cords separated by narrow interstices. The peripheral cord is the largest one. The cords of the apical whorls of the teleoconch are more or less beaded, particularly those nearest to the upper suture. (3) The spiral sculpture in C. zizyphinum is much less prominent than in C. altena, (4) The conspicuous axial sculpture of the apical whorls of the latter species is absent in C. zizyphinum.
C. altena resembles Alertalex (= Calliostoma) blacki Dell, 1956. The latter is known from the region between the Chatham Islands and New Zealand at depths between 400 and 510 m. It has a spiral sculpture of two very prominent cords, the apical one located just below the suture and a stronger
one at the lower third of the whorl. Between these two is a less distinct cord. All three cords are nodulose. The body whorl has a strong tripartite cord. C. blacki lacks the distinct cancellate sculpture of the apical whorls found in C. altena.

Type Location: Near Pulu Tonijn, Makassar Strait, S.W. of Celebes, Indonesia, 5° 3^ S 1180 3^ to 38' E; depth more than 900 m; collected by navail officer Land during sounding operations for a submarine telegraph cable; don. J. D. Pasteur; received November 1891. — One shell without the soft parts. The original label states that it was taken alive.