General Remarks.—I have come to the same conclusion with Prof. Macgillivray, concerning the variability of this form, and I believe there is only one true species. With respect to Dr. Coates’s species, viz., Otion depressa and O. saccutifera, though I have not seen specimens, I can hardly doubt, from the insufficient characters given, that they are mere varieties.
With respect to the ear-like appendages, we shall presently see in C. virgata, that at corresponding points on the capitulum ([Tab. III], [fig. 2 b]), there are two slight, closed prominences. According to Professor Macgillivray, in C. aurita, every gradation can be followed by which the appendages, at first closed, become tubular and open. The opening would ensue, if the corium became absorbed at the bottom of the appendages whilst still imperforate, for then the inner tunic would be cast off at the next moult and would not be re-formed, whilst the outer membrane would gradually disintegrate together with the other external parts of the capitulum, and not being re-formed at this point, an aperture would at last be left. These appendages have no relation to the generative system: the ovarian tubes, which surround the sack do not extend into them; nor do the ovigerous lamellæ. I believe, that their function is respiratory: the corium lining them is traversed by river-like circulatory channels, and their much-folded, tubular and open structure must freely expose a large surface to the circumambient water. Why this species should require larger respiratory organs than any other, I know not. In this species, moreover, the filamentary appendages are developed to a greater extent than in any other cirripede; in most genera, the surface of the body and of the sack suffices for respiration.
![[fig. 2 b]](#475865927904411783_p03f2b.png.id-6658432206995480343.wrap-0.html.html){kind=link}
2. Conchoderma virgata. [Pl. III], [fig. 2.] [Pl. IX], [fig. 4.]
![[Pl. III]](#475865927904411783_p03.png.id-7162692094793147528.wrap-0.html.html){kind=link}
![[fig. 2.]](#475865927904411783_p03f2.png.id-224626442937131809.wrap-0.html.html){kind=link}
![[Pl. IX]](#475865927904411783_p09.png.id-286607803299793274.wrap-0.html.html){kind=link}
![[fig. 4.]](#475865927904411783_p09f4.png.id-6310314689087175771.wrap-0.html.html){kind=link}
Lepas Virgata. Spengler. Skrifter Naturhist. Selbskabet., B. i, 1790, Tab. vi, fig. 9.
—— coriacea. Poli. Test. utriusque Sicil., Pl. vi, fig. 20, 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.