Shell shaded, and often longitudinally striped with bright pink. Scutum as in [B. psittacus]. Tergum with the apex produced and needle-like, white: spur placed at its own width from the basi-scutal angle.
Hab.—Cape of Good Hope. Attached to stems of Fuci, Algoa Bay. Mus. Brit. and Bowerbank. Attached to a Patella, Mus. Darwin, Mus. Cuming, and Stutchbury. Attached to floating kelp, Lagulhas Bank, Mus. James Ross, associated with [B. tintinnabulum] and [spongicola].
This species comes extremely close to the South American [B. psittacus], and I should hardly have attached a specific name to it, had I not examined many specimens, young and old, of the true [B. psittacus], from Peru, Chile, and Eastern Patagonia, and found them all identical in the few, apparently trifling points, in which that species differs from [B. capensis]. The animal’s body and the shell agree in every respect, excepting that the shell is decidedly pinker, being often most distinctly and prettily striped longitudinally with pale and bright pink. In some of the specimens the basis is cup-formed: in some, the broad radii are pale pink, in others they are quite white, and in this latter case a singular aspect is given to the pinkish varieties. In very large specimens (and I have seen one fully two inches in basal diameter) the pink colour is extremely feeble, and the whole shell has a very rugged, disintegrated, coarse, and sometimes dirty appearance: in most of these large specimens the walls are more massive than in [B. psittacus], and the orifice of the shell rather smaller; in some, however, the walls certainly are of unusual thinness.
The Scuta differ from those of [B. psittacus] only in the basi-tergal corner not being so much rounded off, and consequently in the articular ridge, which is rather more reflexed, descending in proportion lower down the valve: the cavity at the basi-tergal corner is in proportion broader. The valves in the two species differ, also, but only in young specimens, in the occludent half being tinted, both externally and internally, purple, whereas in [B. psittacus] the whole valve, at all ages, is white. In the terga the spur is removed fully its own width from the basi-scutal angle, whereas it is not half this distance in [B. psittacus]. The scutal margin is here much more inflected. In [B. psittacus] there is a remarkable patch of purple on the inside of the valve, between the articular ridge and a second special ridge; of this purple patch there is here no trace, consequently the beak or apex is white. The beak, also, is less prominent. The special ridge, just alluded to, here runs much nearer to the articular ridge, and is less prominent: indeed, in old specimens, it is often almost obliterated. Finally, the whole valve, in proportion to the Scutum, is rather broader.
I have seen a young specimen, about a quarter of an inch in basal diameter, with the orifice of the shell toothed owing to the obliquity of the summits of the radii; and this gave the shell a very peculiar aspect. The largest well-coloured specimen which I have seen is 1.2 of an inch in basal diameter; but in Mr. Cuming’s collection there are two rugged, disintegrated specimens, two inches in basal diameter, and two and a half in height. Some specimens, 1.3 in basal diameter, in Mr. Stutchbury’s collection, are remarkable from the radii having been obliterated—the shell being merely divided by six sutures, as we have seen is likewise sometimes the case with large specimens of [B. psittacus].
This species is evidently a South African representative of the South American [B. psittacus].
5. [BALANUS] NIGRESCENS. Pl. [2], fig. [5 a], [5 b].
BALANUS NIGRESCENS. Lamarck, (1818) in Chenu. Illust. Conch., Tab. 4, fig. 16.
------ GIGAS. Ranzani. Memoire di Storia Nat., 1820, Tab. 3, fig. 5, 6, 7.