Page:New land mollusks from Madagascar and Mexico.djvu/9

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. 11. Bulimulus (Rhabdotus) fonsecanus, new sp. CNHM No. 106702, type, front and back views; about × 2.

Relationships.—The species here described seems to be most closely related to Bulimulus (Rhabdotus) baileyi Dall from the Mexican state of Sonora. The fact that the new fonsecanus does not show any surface sculpture, as baileyi does, may be due to the fact that the type, the only specimen at hand, has been collected dead in a rather worn down state. However, there are characteristic differences between the two species: fonsecanus has seven whorls instead of the five to six in baileyi, and the shape of the aperture is different; in baileyi the ends of the peristome converge without a noticeable callus between them, while in fonsecanus the ends of the peristome do not approach each other and are united by a conspicuous callus.

Remarks.—The region of the Gulf of Fonseca, the locality of this new species, is much farther south than any other known locality of a member of the subgenus Rhabdotus.

Polygyra (Erymodon) hertleini, new species. Figure 12, a-c.

Diagnosis. A depressed, slightly angulated shell with a low spire, the surface almost densely ribbed by regular growth lines, the umbilical region with a perforate umbilicus, the aperture lipped,