BALANUS TULIPIFORMIS EX CORALLIO RUBRO. Ellis.[88] Philosoph. Transactions, vol. 50 (1758), tab. 30, fig. 10.
LEPAS TULIPA. Poli. Test. utriusque Siciliæ, tab. 5, fig. 1. et 6 (1791).
BALANUS TINTINNABULUM (var.) Chenu. Illust. Conch., tab. 3, f. 5.
[88] According to the letter of the Rules of the British Association, Ellis’s name ought to be retained, as it was published in 1758, the same year during which the 10th edition of the ‘Systema Naturæ’ appeared, in which edition the binomial method was first used. But as Ellis himself did not then know of, or follow this method, it might be disputed whether, according to the spirit of the law, his name ought to stand. The only other name given to this species is that of tulipa, affixed by Poli in 1791, but this name had been previously used by Müller in 1776, and by Chemnitz in 1785, for another species, the B. Hameri of this work; and likewise, also previously to Poli, by Bruguière in 1789, for still another species, viz., B. tintinnabulum of this work: under these complicated causes of confusion, I think it is highly advisable to adopt Ellis’s name. I may add that the B. tulipa of Mr. G. B. Sowerby is the B. tintinnabulum of this work. It is possible that the B. conoides of Brown, ‘Illustrations Conch.’ (1st edit. pl. 6, fig. 7), may be our present species; but without details of structure it is hardly possible to identify, in many cases, the species of Balanus.
Shell dark rose-coloured, sometimes tinged with purple; orifice toothed. Scutum externally very smooth, covered by membrane. Tergum with distinct crests for the depressor muscles.
Hab.—Sicily, Malta, Malaga, (associated with B. perforatus), Madeira. Often growing in clusters and associated with Pachylasma giganteum. Attached to Millepora aspera, oysters, and other shells. According to Poli, an inhabitant of deep water; yet in mus. Cuming there are two fine specimens attached to the always floating Lepas anatifera. Mus. Lowe, Macandrew, Stutchbury.
General Appearance.—Shell tubulo-conical or conical: orifice large, toothed, approaching to pentagonal. Surface moderately smooth, naked. Colour rosy, or tile-red, with a slight tinge of purple; or beautiful rich purple. Radii nearly as dark as, or darker than, the parietes. The portion of the alæ seen externally is generally white. Internally the whole shell is nearly white. Generally the tints outside vary in transverse fasciæ; sometimes there are very fine, dark, longitudinal lines. Largest specimen (from Malta), 1.4 of an inch in basal diameter; usually full-sized specimens are about three quarters of an inch in basal diameter.
Scuta (Pl. 2, fig. 2 a, 2 c) very smooth, with the growth-ridges very little prominent, sometimes there are obscure traces of longitudinal striæ; surface covered by an unusually thick and persistent yellow membrane: valve narrow, with the upper part commonly reflexed: the basal margin forms, with the occludent margin, a smaller angle than is usual: the tergal margin of the valve is rectangularly inflected, instead of being, as is usual, merely bowed inwards. Internally, the articular ridge is rather prominent. The depth of the slight pit for the lateral depressor muscle is variable; it sometimes includes a minute, central, longitudinal ridge.
Terga (2 b, 2 d): the longitudinal furrow is deep, with the sides folded in; the spur is placed at about its own width from the basi-scutal angle; it is moderately long, with its lower end obliquely rounded off; but the length, breadth, and precise outline of the lower end varies a little. The basal margin on the opposite sides of the spur, forms a nearly straight line, but with the portion on the carinal side very slightly hollowed out. Crests for the depressor muscle are well developed.
Compartments.—The radii and alæ always have their summits oblique: the sutural edges of the radii are deeply penetrated by pores between the strongly denticulated septa: the sutural edges of the alæ are quite smooth: the tubes in the parietes are crossed in the upper part of the shell by septa. Basis tubular, with an underlying cancellated mass.
Mouth.—Labrum with the teeth either absent or very small: mandibles with the fourth and fifth teeth rudimentary: maxillæ with a small notch under the two upper spines; near the lower angle, two spines, one beneath the other, are larger even than the upper pair; beneath the lower pair, there is a tuft of fine spines. Cirri, segments protuberant in one ramus of the first cirrus and in both rami of the second cirrus; posterior cirri with the segments short and broad, each bearing three pairs of spines, with a small intermediate tuft.
Affinities.—This species in all essential respects comes very near to the three last varieties of B. tintinnabulum, which have the orifices of their shells toothed. The smoothness of the scutum, with its persistent epidermis,—its peculiar shape,—its small and not reflexed articular ridge,—together with the crests on the tergum for the depressor muscles, are sufficient diagnostic characters. Even in general habit and tint of colour, this species has a different aspect from B. tintinnabulum. In some respects B. tulipiformis leads into the species included in the third section of the genus.