. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. MESODON. 329 Readily distinguished from the allied species by the very angular and broad reflection of the peristome. Animal grayish on the sides and posterior extremity, brownish on the upper parts, darker on the head and neck; foot long and narrow; eye- peduncles long and slender; eyes black. (See Bost. Journ. Nat. Hist., I. PI. X.) Jaw as usual in the genus; 14 ribs. Lingual membrane (PI. VIII. Fig. J) with 32—1—32 teeth, with 15 laterals. Mesodon Roemeri, Pfeiffer. Shell with a narrow, or partially covered umbilic
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. MESODON. 329 Readily distinguished from the allied species by the very angular and broad reflection of the peristome. Animal grayish on the sides and posterior extremity, brownish on the upper parts, darker on the head and neck; foot long and narrow; eye- peduncles long and slender; eyes black. (See Bost. Journ. Nat. Hist., I. PI. X.) Jaw as usual in the genus; 14 ribs. Lingual membrane (PI. VIII. Fig. J) with 32—1—32 teeth, with 15 laterals. Mesodon Roemeri, Pfeiffer. Shell with a narrow, or partially covered umbilicus, sometimes imperforate, depressed, rather thin, closely striated, rather transparent and smooth, horn- colored ; spire slightly elevated; suture lightly impressed; whorls 5, rather convex, increasing slowly, the last one Kg 2i2. subcarinaje at its periphery, scarcely descending; aper- ture lunar, oblique, generally slightly contracted by a parietal denticle which obliquely enters the mouth of the shell; peristome white, thickened, the upper portion hardly expanded, reflected below, and at the columellar junction spreading into a thin, partial covering to the umbilicus. Greater diameter 21, lesser 18 mill.; height, 10 mill. Helix Roemeri, Pfeiffer in Roemer's Texas, 455 (1849); Zeitschr. f. Mai. 1848, 117.— Reeve, Con. Icon., No. 680. —W. G. Binney, Terr. Moll., IV. 55; L. & M. Roemeri. "W. Sh., I. 146, Fig. 250 (1869). Helix dcntifera, part, Pfeiffer, Mon. Hel. Viv., III. 260 ; in Chemnitz, ed. II. 331, PI. CXXXI. Figs. 1-3, not of Binney. Mesodon Roemeri, Tryon, Am. Journ. Conch., III. 43 (1867). Near New Braunfels, Texas; Washington County, Williamson County, Bosque County, and Colorado River, Texas. A species of the Texas Subregion. This species was formerly confounded by Pfeiffer with dentifera, an authen- tic specimen of which he had not seen. It is quite a distinct species, and in- habits a distinct geographical region. It may be distinguished fro
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