LEPAS PUNCTATUS. Montagu (!). Testacea Britannica (1803).

Shell white or gray, generally much corroded and punctured: radii (when present) narrow, with their sutural edges most finely crenated; tergum with the crests for the depressor muscle depending barely beneath the basal margin.

Var. (a, communis) fig. [1 a], [1 f]: Shell conical depressed, upper part corroded, walls folded, sutures moderately plain or obliterated; radii not developed; orifice broadly oval.

Var. (b): Shell elongated, sub-cylindrical; sutures obliterated; surface much corroded; orifice almost circular.

Var. (c, communis) fig. [1 c], [1 e], [1 h]: Shell conical, folded, sometimes covered by membrane; radii developed, narrow; orifice sub-hexagonal, toothed.

Var. (d, fragilis) fig. [1 d]: Shell conical, smooth, thin; compartments easily separable, pale-coloured; radii developed, narrow; orifice large, toothed, sub-hexagonal.

Var. (e, depressus) fig. [1 b], [1 g], [1 h]: Shell much depressed, surface much corroded, smooth: alæ largely exposed, marked by lines of growth: radii not present; parietes on the under side often supported by pillars; orifice sub-hexagonal.

Hab.—Southern shores of England, Ireland, Isle of Man, Mediterranean, Madeira, Cape de Verde Islands, Southern United States (Charlestown), West Indies, Brazil (Bahia), Rio Plata (Guritti Island), Red Sea, Philippine Archipelago, Coast of China, Gulf of Corea, Oregon or Northern California.

This species is very widely distributed and extremely common. On the coast-rocks of the southern shores of England it is, in parts, even more numerous than the [Balanus balanoides], with which it often grows mingled. As already stated, it is often confounded in British collections with this species of [Balanus], under the name of Balanus punctatus; that Montagu had this [Chthamalus] in view, when describing his Lepas punctatus, is certain, from his original specimen in the British Museum, but whether this was the case with his predecessor, Pulteney, in the Dorset Catalogue, I do not feel so sure. [Chthamalus stellatus] varies, as we shall immediately see, extremely in appearance. Some of the varieties, as var. depressus, which in external aspect are especially distinct, I have no doubt are really varieties, but whether this is the case with some of the forms from the more distant localities, is a little more doubtful; but I beg that it may be observed, that I have, in the case of every one of the varieties, and of all the specimens from distant localities, cleaned with potash and most carefully examined the disarticulated valves, and likewise dissected the included animal’s body.