"Cocculina superba, new species
Description. Shell patelliform, large, white to greyish white, weakly sculptured and of medium thickness. Apex elevated, deciduous, centrally located, and directed posteriorly. Shell convex anteriorly and somewhat concave posteriorly. Aperture sub-ovate and narrower anteriorly. Sculpture consisting of numerous, irregular lines of growth, and more numerous, less well-defined radial threads. About twelve concentric lines more prominent and evenly spaced between apex and margin. Radial threads low, crowded, and numbering about 140.
The animal, first preserved in formalin and later in alcohol, is 21 mm long, 16 mm wide, and light yellowish in colour. The head, which is 5.8 mm long and 5.5 mm wide, bears on its ventral surface a large, muscular, posteriorly directed proboscis measuring 2.8 mm and 3.5 mm across the ovate distal end. One tapering, recurved, ventrally directed tentacle, about 3.0 mm long, is present on each side of, and above, the proboscis. The intromittent organ projects from the visceral mass on the right side of the animal adjacent to the base of the head. Contracted in preservative, it is tapered, concentrically wrinkled, 1.0 mm in basal diameter, and 3.0 mm in length. The short anal papilla lies at the left of the intromittent organ and a little in front of it. The foot is muscular, with a crenulated edge, flattened, and nearly circular except anteriorly, where it is bent ventrally by the muzzle. It measures approximately 12.8 mm in length and 12.1 mm in width. The mantle is appressed to the shell and surrounds the head and the foot.
length
width
height
32*
26
9 mm
holotype
Types. The holotype, a unique specimen, was collected on March 28, 1959, at R/V Vema biology station 210: latitude 47° 57.5' S., longitude 48° 03' W., and 3,334 fathoms depth (corrected) in the Argentine Basin, approximately 800 miles east of Deseado, Argentina. It is now at the Lamont Geological Observatory, Palisades, New York.
Remarks. In shell characters, C. superba is quite different from all previously described species of Cocculina. C. maxima Dautzenberg is differently shaped and proportionately much higher (23 mm long, 16½ mm wide, and 16½ mm high). C. rathbuni Dall has flattened sides, is narrower and more depressed, and the apex is less conspicuously tilted. The other species are all very small and differ in a number of characters.
Under C. rathbuni Dall, Pilsbry (1890: 132) states: "Length 11, breadth 6.5, height 2.75 mill. Another dead specimen is three times larger." Apparently this larger specimen is not at the United States National Museum nor at the Philadelphia Academy of Natural Sciences and must be presumed lost. If Pilsbry's casual statement may be taken literally, C. rathbuni shares with C. superba the distinction of being the longest species of Cocculina (33 mm), although superba is wider and higher. of course the maximum size attained by these species is indeterminate at the present time.
* One mm chipped away posteriorly."
(Clarke, 1960: 3-4)
