Notes on American Land Shells and Other Miscellaneous Conchological Contributionsv.2 Volume 2, pts. 2-3 - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 Excerpt: ...the reflection equalling the length of the base of attachment, and very irregularly denticulated, there being usually one long, blunt, oblique, inner, bifid cutting point, the outer division much the shorter, and several short, blunt, outer cutting points. P. Wetherbyi (pi. VI., fig. 13), the only other species now known, has 35--1--35 teeth, with 13 perfect laterals. The teeth are different from those of P. dorsalis, and nearer those of Tebennophorus Caroliniensis. The side cusps of the centrals and laterals are subobsolete, and have no distinct cutting points, the median cusp is much more produced, stouter, and bears a stout, blunt, cutting point. The marginal teeth are not so wide, they are less irregularly denticulated, having usually one long, stout, blunt, oblique, inner cutting point, and one shorter side cutting point. Genus HELIX, Lin. In common with all who have studied the genus Helix, I am convinced of the necessity of recognizing among its species numerous distinct genera. I have, however, at this time eliminated those species only whose jaw has no distinct ribs upon its anterior surface.1 The balance of the species I retain grouped as subgenera'-' only. Before recognizing these groups as distinct genera, I desire to wait until we can ascertain whether generic characters 1 I fear that even this rule will not hold good. In some subgenera of Helix the absence or presence of ribs on the jaw is not a reliable character. For instance, in Dentellaria we have found the jaw of //. Joiephina and formom without ribs. H. dentient, badia, paehygattra are heavily ribbed. H. lyehnuchut, nudeola, and perplexa less so. 2 In the list of species given above (p. 152), I have used only the subgeneric names. The lingual membrane of obvoluta is described by Goldfuss...
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