1795.

---- MEMBRANACEA. _Montagu._ Test. Brit. Supp., p. 164, 1808, et
Linn. Trans., vol. xi, Tab. xii, fig. 2.

CONCHODERMA VIRGATUM. _Olfers._ Magaz. Gesells. Naturfor. Freunde,
Berlin, 1814, p. 177, (3d Quartel).[38]

BRANTA VIRGATA. _Oken._ Lehrbuch der Gesell., Th. ii, p. 362,
1815.

SENOCLITA FASCIATA. _Schumacher._ Essai d'un Nouveau Syst., 1817.

CINERAS VITTATA. _Leach._ Encyclop. Brit. Supp., Tom. iii, Plate.
1824.

---- CRANCHII (!) CHELONOPHILUS (!) OLFERSII (!). _Leach._
Tuckey's Congo Expedition, p. 412, 1818.

---- MEGALEPIS (!) MONTAGUI (!) RISSOANUS. _Leach._ Zool. Journal,
vol. ii, p. 208, 1825.

---- MEMBRANACEA. _Macgillivray._ Edin. New Phil. Journal, vol.
xxxix, p. 171, 1845.

---- BICOLOR. _Risso._ Hist. Nat. des Productions, &c., 1826, Tom.
iv, p. 383.

---- VITTATUS. _Brown._ Illust. of Conch., 1844, Pl. li, figs.
16-18.

GYMNOLEPAS CRANCHII. _De Blainville._ Dict. des Sci. Nat. Hist.,
1824.

PAMINA TRILINEATA (!) (Var. Monstr.). _J. E. Gray._ Annals of
Phil., vol. x, 1825.

[38] See page 136 respecting this date.

_C. Scutis trilobatis: tergis intus concavis, apicibus introrsum leviter
curvatis: carina modica, leviter curvata: pedunculo in capitulum
coalescente._

Scuta three-lobed: terga concave internally, with their apices slightly
curved inwards: carina moderately developed, slightly curved: peduncle
blending into the capitulum.

No filament attached to the pedicel of the second cirrus.

_Var. chelonophilus_ (Pl. III, fig. 2 _c_). Terga, minute, nearly
straight, solid, acuminated at both ends, placed far distant from the
other valves: carina, either minute and acuminated at both ends, or
moderately developed and slightly arched and blunt at both ends: lateral
lobes of the scuta broad: valves imperfectly calcified.

_Hab._--Mundane: extremely common on ships' bottoms from all
parts of the world. Falkland Islands. Galapagos Islands, Pacific
Ocean. Attached to sea-weed, turtle and other objects. Often
associated with _Conchoderma aurita_, _Lepas anatifera_, _L.
Hillii_, and _L. anserifera_.

_General Appearance._ Capitulum, flattened, gradually blending into the
peduncle; summit square, rarely obtusely pointed. Membrane, thin.
Valves, thin, small, sometimes imperfectly calcified, very variable in
shape and in proportional lengt