4. BALANUS CAPENSIS. Pl. 2, fig. 4 _a_, 4 _b_. BALANUS CAPENSIS ORE OBLIQUO. _Ellis._ Phil. Transact., vol. 50 (1758), Tab. 34, fig. 14. _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.