. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. POLYGYRA. 269 last whorl, which prevails in auriculala, and the forms represented by Dr. Bin- ney as varieties of it. It is very rare in collections: I know of but two speci- mens of it. Jaw with over 12 ribs. Lingual membrane as usual in the genus; teeth 17—1—17, with 8 laterals. (PL XV. Fig. L.) Polygyra ventrosula, Pfeiffer. Shell rimately perforated, globosely depressed, thin and shining, pellucid, delicately striated, horn-colored ; spire slightly raised ; whorls 5, but little con- vex, the last one subangulated
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. POLYGYRA. 269 last whorl, which prevails in auriculala, and the forms represented by Dr. Bin- ney as varieties of it. It is very rare in collections: I know of but two speci- mens of it. Jaw with over 12 ribs. Lingual membrane as usual in the genus; teeth 17—1—17, with 8 laterals. (PL XV. Fig. L.) Polygyra ventrosula, Pfeiffer. Shell rimately perforated, globosely depressed, thin and shining, pellucid, delicately striated, horn-colored ; spire slightly raised ; whorls 5, but little con- vex, the last one subangulated above, falling suddenly towards the aperture, inflated below, anteriorly gibbous and contracted; lg aperture very oblique, ringent; peristome acute, broadly reflected, its terminations scarcely approaching each other, but joined by two white, elevated laminae, which are placed at acute angles on J ', r ° P. ventrosula. the parietal wall; the basal margin is also furnished with two white acute denticles ; on the right margin is placed a white sub-perpendicular, extended lamina. Greater diameter 13, lesser 11 mill.; height, 1\ mill. Helix ventrosula, Pfeiffer, Proc. Zool. Soc. 1845, 131 ; Mon. Hel. Viv., I. 417 ; in Chemnitz, ed. 2, I. 373 (1846), PL LXV. Figs. 5, 6 (1849). —Reeve, Con. Icon., No. 687 (1852).—W. G. Binney, Terr. Moll., IV. 73, PL LXXVII. Fig. 14; L. & Sh., I. 92, Fig. 164 (1869).—Crosse and Fischer, Moll. Mex. et Guat. 274 (1870). Dcedalochila ventrosula, Tryon, Am. Journ. Conch., III. 63 (1867). A Mexican species, found also in the Texas Subregion. Jaw strongly arcuate, of uniform width, ends blunt, anterior surface with 8 broad ribs, crenulating both margins (see Fig. 157, p. 263). Lingual membrane with 93 rows of 24—1—24 teeth each, 9 laterals; cen- trals tricuspid, the side cusps very small; laterals of same shape, but bicuspid; Fig. Lingual dentition of P. ventrosula. marginals with one inner, oblique, bluntly bifid cutting po
Size: 3256px × 768px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorha, bookcentury1800, bookdecade1870, booksubjectzoology
