We have been at some pains in our endeavours to reconcile our mind to the idea of introducing this Tortoiseshell Harp as a species distinct from the Buccinum Harpa, in conformity with the opinion of Dr. Solander. We have compared our shell with the acknowledged type of the Linnæan species, with every attention, and are compelled, in truth, to allow, that however distinct it may appear upon the first glance of inspection, we cannot implicitly accede to the persuasion of its being specifically distinct. Placing this remarkable variety with that particular shell, the true Buccinum Harpa, the less informed Conchologist would assume as certain that the difference existing between the two removed them sufficiently from each other. Arrange these, however, with those varieties and transitions of the Common Harp that approach the nearest in appearance to both kinds, and we shall then perceive such a close analogy, such an intermediate catenation, as will induce a pause, and certainly under the impression with which we view them, an idea that these variations arise only from local causes, and are not specifical distinctions. As a marked and well distinguished variety we have retained the term testudo, which Dr. Solander had assigned to it; but as a distinctive appellation of it as a variety, and not as a shell altogether distinct.
That it may not be imagined we feel any disposition to object against those changes in the Science of Conchology, which the more advanced state of our present knowledge may demand, we have no hesitation in adding that in our own opinion the Harpa family should constitute a very distinct tribe from the other Buccini; we believe, also, that had Linnæus lived to reconsider them, he would have comprehended them together as a genus. The French writers have long since done so. De Monfort advances that Lamarck was the first who separated the Harps from the Linnæan Buccinum. This we have already shewn to be an error. Lamarck’s example in proposing them as a genus in his Système des Animaux sans Vertèbres, published in the year 1801, and his subsequent observations in other writings, has tended to establish them as a genus; he was not its first proposer.
It may not be amiss, in conclusion, to observe, that Lamarck has taken for the type of his genus, the variety figured by Lister, in his Conchology, tab. 992 f. 55, the shell which he denominates Harpa Ventricosa. The leading character of his genus consists in the shell being of an oval form, ventricose or swollen, and having the surface furnished or beset with longitudinal, parallel, and sharp or acutely edged ribs. The opening or mouth, oblong, ample, abbreviated or cut off below, and without canal. The pillar, or inner lip, smooth, or without plaits or tubercles, and terminating in a point at the base. The absence of a canal is one material character by which the Harpa genus, as thus laid down, is to be distinguished from the new genus Trophon, to which, in some respects, at least, it bears a general resemblance. The definition of the genus by De Montfort is rather different from that of Lamarck: according to De Montfort the shells of this family are globose; the first whorl very far surpassing the rest in size, and the spire obtuse. The mouth is very open. The pillar or inner lip smooth and rounded. The outer lip bordered by an acutely edged rib or ridge, running paralled to those with which the shell is traversed externally, and the base cut off. The spire in the true Harpa, according to this writer, forms a kind of little domes, one surmounting the other, and the spire, instead of ending in an acute point, terminates in a small mammillated knob.
All the known varieties of this natural family are inhabitants of the deep waters of the sea, and the animal inhabitants appear to have remained hitherto undescribed. They are confined chiefly to the Indian Seas. The variety known by the name of Nobilis is a native of Japan; there is another found in China, distinguished by the name of Chinensis: both these are considered by Dr. Solander as the Buccinum Harpa of Linnæus: there is one kind found at Ceylon, and another at Madagascar, which are to be esteemed distinct species. The sanguineous Harp, from the Coast of Guinea, is the Buccinum pandura of Solander. The Harp, distinguished by having a far greater number of elevated ribs than any of the preceding, is from the seas of the Phillippine Isles, and is certainly a distinct species. The very fine variety which constitutes the more immediate object of our present illustration, the Tortoiseshell Harp, is a native of Madagascar: its length is four inches, and its greatest breadth two inches and a half.
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London. Published by E. Donovan, Simpkins & Marshall, June 1.st 1822.