MOLLUSC A— GASTROPODA. 595. 



V. Peripheral margin more or less strongly angulated but not sharp ; surface with 



regular ornamentation 12. 



12. Non-umbilicated XCI. Calliostoma. 



12. Umbilicated 15*.. 



15*. Umbilicus with distinct and notched spiral CVI. Solarium. 



15*. Umbilicus without markedly notched margin or spiral. 



XCI A. Eutrochus. 



V. Periphery sharply angular, often produced, surface frequently modified by 



cementation of foreign substances CXVII. Xenophora. 



F. Shell turreted, mostly high-spired, with round or more rarely flattened and angulated 

 whorls, and entire aperture without peripheral notch or slit VI. 



VI. Non-umbilicate 13. 



13. Surface smooth, except for lines of growth 16*. 



16*. Whorls flattened, sutures scarcely or not at all impressed t. 



t. Columellar lip with tooth CIV. Odostomia. 



t. Columellar lip with several oblique folds. 



LXXXVIII. Soleniscus. 



t. Columellar lip smooth 999. 



999. Dextral, aperture elongate ss.. 



ss. Inner lip only visible in lower half. 



LXXXVI. Meekospiria. 



ss. Inner lip complete nf. 



I if. Shell smooth and lustrous, protoconch dextral. 



C. Eulima^ 

 I if. Shell thick, apex generally wanting, not dextraL 



CXXX. Goniobasis. 



999. Sinistra], aperture ovoid CCXII. Physa. 



16*. Whorls rounded, sutures more or less deeply impressed u. 



u. Body whorl long, one half or more of length of shell, aperture 

 elongate, suture sometimes with narrow shelf. 



LXXXVI I. Bulimorpha, 

 u. Body whorl much longer than the spire, aperture elongate, an- 

 teriorly somewhat drawn out LXXXV. Fusispira. 



u. Aperture rounded, body whorl not very large Ill I. 



nil. With fine sigmoid striae LXXXI. Loxonema. 



nil. Without striae (when perfect showing a faint peripheral: 



band ) XLVI. Hormotoma. 



13. Surface ornamented with ribs or spirals or with both 17*. 



17*. Spiral sculpture dominant v. 



v. With fine sigmoid transverse lines LXXXII. Aclisina* 



v. With lines of growth not sigmoid 2222. 



2222. Spirals few (2 or 3) or absent tt. 



tt. Whorls rounded, one or more spirals nodose. 



LXXVIII. Acanthonema . 



tt. Whorls angular, spirals not noded I2f. 



I2f. Short and tapering, embracing to angulation. 



LXXXII I. Orthonema. 

 I2f. Very long and slender, generally not embracing 



to angulation CXXI. Turritella. 



2222. Spirals numerous ; spire high and slender, many- 

 whorled uu.. 



