Mr. R. Etheridge, Jun., on Gasteropoda. 289 In some places, probably where the superficial calcareous layer is thin, the pearly iridescence beneath it is observable. The oblique flexuous costas are about nineteen in number on the penultimate, and a trifle more numerous upon the last whorl. Yoldia Vancouver ensis. Shell almost equilateral, transversely elongate-oval, acumi-nated posteriorly, slightly gaping at both ends, clothed with a greenish olivaceous epidermis, which is darker towards the ventral margin and varied at intervals with dark zones. Surface not very glossy, marked with concentric lines of grovvthand close microscopic striation and granulation. An-terior side a trifle the longer, regularly rounded at the margin, posterior more acute. Hinder dorsal slope nearly rectilinear, scarcely arcuate. Area distinct. Length 12 millims., width 224, diam. 6. This species is narrower posteriorly than Y. arctica, Gray, which it somewhat resembles, less glossy, and is very minutely granular upon the surface, this sculpturing being only discern-ible under a powerful lens. XXXV. — Notes on the Gasteropoda contained in the Gilbertson Collection, British Museum, and figured in Phillips's 1 Geology of Yorkshire.'' By R. Etheridge, Jun., F.R.Ph.S.Ed. [Continued from vol. v. p. 485.] The Species figured on Plate XIV. Patella scutiformts, Phillips (p. 223, t. 14. fig. 1). The figure is drawn from a somewhat crumpled and frag-mentary specimen, which bears a considerable resemblance to the subject of the next figure, P. sinuosa. From this imper-fection the species will not be easy of recognition in collec-tions, as it is impossible to say what the exact outline was, whether the margin was entire or sinuous. It certainly ap-pears to be rounder than P. sinuosa, more depressed and to have a smaller apex ; it is, however, a question, I think, whether these forms can be retained as more than varieties of one another. Professor M'Coy appears to consider P. scutiformts a good species, from its depressed form and marginal apex. I would, however, observe that in the absence of the broken end
BioStor
