OCR Text |
Show 1875.J MR. E. A. SMITH ON THE GENUS AEABA. 539 And here I cannot refrain, although always averse to censuring criticism, from condemning most energetically that pernicious practice of describing fragments of minute specimens and assigning specific names to them. It merely results in burdening science with a mass of literature almost useless ; for it is simply an impossibility for any one to identify their specimens from the description of those miserable fragments characterized in the Mazatlan Catalogue. Describe them and welcome, for no harm is thereby done, albeit but little good ; but for the sake of others let us not name them. Biala leithii. DlALA LEITHII, sp. 110V*. Testa imperforata, ovato-fusiformis; spira acuminata, tenuis, parum nitida, sordide fiavida, fasciis spiralibus angustis rufis parum conspicuis ornata, una. circa medium anfr. superiorum, duabus in ultimo, alt era paululum supra, altera paululum mediumin-fra; anfractus 9, convexi, medio levissime angulati, spiraliter tequidistanter striati, striis in anfr. superioribus circiter 8, in ultimo ad 18; sutura parum obliqua, profundiuscula; apertura ovata, ad basin acuminate effusa, longitudinis totius ad y-i cequans,fasciis externis bifasciata; columella arcuata leviterque incrassata ; labrum tenue, simplex. Operculum corneum, tenue, paucispirale, nucleo subcentrali. Long. 7\ mill. Diam. fere 3. Hab. California. The angulation of the whorls is very slight in most specimens, and in some altogether absent. The spiral reddish bands are not very observable, but are more distinctly observable within the aperture ; indeed that which encircles the middle of the upper whorls is so faint as to be scarcely visible. The operculum consists of about three volutions; and its nucleus is situated at about one fourth the entire len°-th from the inferior margin. Dr. Leith, who has kindly presented'a good series of this species to the Museum, enclosed with them the following notes, which he made respecting the animal when observing it alive. " Lip somewhat proboscidiform, not used in progression, and not usually projecting beyond the edge of the foot. |