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Show 1880.] LAND-SHELLS O F M E N T O N . 109 when he obtained more than a dozen magnificent specimens, though I was most anxious to increase m y knowledge of what were the undoubted associates of this remarkable mollusk. A proper and thorough investigation of this deposit at Cape Mortela still remains for some future naturalist. It was a little too far for m y now very limited powers of walking, but is not so for any one in fair ordinary health, living in the East Bay. I am convinced this species has nothing to do with the subgenus Macularia, with which, at first sight, it shows some affinity; I think it nearly certain it was a true Tachea. I could discover no trace of this species in deposits A to F. Alt. 29, diam. 4If. A common depressed form from Cape Mortela. Alt. 34, diam. 46. Cape Mortela. Alt. 3 H , diam. 41f ; apert. alt. (cum perist.) 23|, (sine perist.) 19, lat. (cum callos. colum. ac perist.) 251, (sine prseced.) 18 millim. This specimen, from Cape Mortela, has two broad brown bands (the lower one the broader) on the two antepenultimate whorls, four (apparently more or less interrupted) on the last whorl; the two apicals are unusually developed and prominent, horn-colour, and perfectly smooth. HELIX (TACHEA?) MENTONICA, n. sp. Helix vermicularis, Issel, Con. Cav. Ossif. Liguria, figs. 7, 8, 1867, not of Bonelli. Testa ad " Helix vermiculariam, Bonelli," et " H. paretianam, Issel," affinis: imperforata, subgloboso-conoidea, vix solida, oblique striata, ultimo anfractu valide malleato ; albida, zonulis pervariis circumcincta interruptis aut continuis, scepe perspicuo-ribus prope peristoma; spira plus minusve conico-elevata, apice obtuso, Icevigato ; anfract. b\, convexi, regulares, sutura distincta separati, ultimo majore, tumido ac rotundato, ad aperturam abrupte descendente ; apertura ampla, obliqua, subovalis, marginibus callo castaneo ac valido junctis; peristoma castaneum, percrassum, expansum, intus incrassatum; margo columellaris Icevis, ad-pressus, late repZexus. Diam. 32^, alt. 23|; aperturse lat. (cum peristomate ac callo columellari) 19, alt. 17i millim. Subvar. minor. Diam. 29|, alt. 21; apert. lat. 17, alt. 16| millim. This species abounded in deposits A, B, D (in especial), and E, mostly in very bad condition, so much so that out of many hundred specimens which I obtained and carefully examined I have only obtained a few perfect specimens. It is undoubtedly the Helix ver-micularia of Issel, typical specimens of which I examined at Genoa, but differs so much from typical Turin specimens of the true H. vermicularia, Bonelli, that I am unable to accept the identification. The species varies enormously, as, I find, do most mollusks of which large series occur in a circumscribed space. It is not closely |
