OCR Text |
Show 388 MR. R. B. WATSON ON MADEIRAN MOLLUSKS. [Mar. 18, the edge of the basal lip. The lowest is the strongest; and above the highest and feeblest there is some faint trace of others on the whole body-whorl. The embryo whorl is quite smooth. Colour. Pure transparent white, with sometimes a yellowish tinge ; opaque when shell not quite fresh. Spire elongated, ending rather abruptly in a blunt point. Whorls 4-4\, well rounded, long, of gradual increase in length and breadth. Suture oblique, deep. Mouth rather large, projecting, and open ; almost a semicircle from the free advance from the body and full sweep of outer lip, along with the great straightness of the line of the inner lip across the belly. Bluntly pointed above, and a little so below at point of pillar. Outer lip sharp and thin, slightly detached from body, and a very little and openly sinuated, thrown well and roundly out from the line of the body, a little projecting beyond the plane of its surface below, fully arched across base, and joining point of pillar in an angulation. The point of the pillar is very doubtfully, if at all, excavated. Inner lip blunt and rounded, very slightly projecting on pillar, so as to leave a open and shallow umbilical trough, bounded externally by the lowest basal thread. It crosses the body in a very straight line, carried across by a shelf-like and not very narrow callus, and advances a little way out from the body to join the outer lip at almost a right angle. Sh. M. 5. 4. 3. 2. 1. L *059 "024 *025 *016 *01 *006 *003 B *029 *021 *023 *026 *02 *013 -007 Hab. Santa Cruz, 10-15 fathoms; Funchal Bay, up to 50 fathoms; Teneriffe. Of this species I have only found five specimens : probably, like R. tenuisculpta, it belongs to the deeper sea. The operculum I have not seen ; and in the absence of that distinguishing feature, theverv slight excavation at the point of the pillar seems too indeterminate to require the classification of this shell with Rissoina, though I doubt its continuing among the Rissoce. Of three specimens of R. balteata (Manzoni) sent me by Mr. M'Andrew, one is this species (R. lincta), the other two are certainly R. glabrata, Miihlf. From Mr. M'Andrew's specimen, therefore, I have added "Teneriffe" as an additional locality for this species. Its presence, however, among specimens of so-called R. balteata led me further to inquire carefully whether it was not this species which Signor Manzoni meant to describe under that name. But it is impossible to think that this was the case : his description is quite inapplicable to R. lincta ; his figure is still more so ; and, finally, he does not give R. glabrata at all as found at the Canaries. Now, as I have specimens of R. glabrata taken at Teneriffe by Mr. M'Andrew, it is obvious that the species I regard as R. glabrata he reckons a distinct species and describes under the name of R. balteata. |