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Show 1873.] MR. R. B.WATSON ON MADEIRAN MOLLUSKS. 365 across the body; in front it is crossed obliquely by a shallow open depression. Sh. M. 8. 7. 6. 5. 4. 3. 2. 1. L...-159 *063 *069 *027 023 *014 *01 *007 *004 *003 B. ..077 *049 *059 *066 *054 *039 *026 019 "013 *005 Hab. Selvagens, shore. By the specific name I have selected for it, I desire to acknowledge m y obligations to the Baron do Castello de Paiva, to whom I owe it and all the other shells I possess from the Selvagens. They were procured by him from the men who annually visit these somewhat inaccessible islands for barrilha, orzella, and sea-birds. The Rev. R. T. Lowe has given a very interesting notice of the flora of the Selvagens in a little work published three years ago by Van Voorst; I regret that I can communicate so very little regarding their Mollusca. I may take the opportunity, however, of stating the fact, which has not, I think, been published as yet, that Helix coronula, Lowe, has been found (it has been communicated to me by the Baron de Paiva) in these islands, where previously the only land-shell known to exist was H. ustulata, Lowe, a species found nowhere else in the world ; H. coronula has also been found by the Baron's collectors in Bugio (the Southern Deserta) and at Canico, one of the nearest points in Madeira,-facts of great interest in connexion with the distribution of species, and serving to connect through their fauna Madeira and these little islands, which, as regards their flora, are, according to Mr. Lowe, more nearly related to the geographically more contiguous Canaries. RISSOA LEACOCKI, Watson. (Plate XXXIV. fig. 1.) Shell conic-oblong, solid, squarely tubercled, transparent, glossy. The two lines of the spire, from the periphery to the apex ou the left side of shell, and from apex to extreme corner of mouth on the right, are perfectly straight, broken only by the square ditch-like sutures, while the basal line connecting these two is an unbroken curve; this arises from the fulness of the base and the thickness of the pillar. Sculpture, longitudinal threads, 15 to 18, strong, oblique, traceable from whorl to whorl, disappearing on 1| whorl, running down almost to the very point of base ; the last appears as a strong broad white labial rib. Spiral threads of about the same size cross these longitudinal threads, forming large knobs or tubercles at the intersections ; these knobs are less strong on lower part of base, but are often traceable even on the spiral threads of the pillar, where they form the only representatives of the longitudinal threads, which die out in the interstices of the spiral threads on the base. Of these spiral threads there are eight or nine on the last whorl. Two additional but feebler ones generally appear between the three highest just before they reach the labial varix, which they all strongly cross, but stop short of the extreme edge of the mouth, leaving in advance of them a plain narrow margin ; on the fourth and fifth whorls there |