MOLLUSC A— GASTROPODA. 595 



5555. Aperture with notch, but no slit ; a peripheral band gen- 

 erally present yy. 



yy. Band vertical on angulation I3f. 



I3f. Band faint, spire obtuse XXXV. Liospira. 



I3f. Band strong, spire mostly acute. 



XXXVIII. Clathrospira. 



yy. Band on upper side of angulation I4f. 



I4f. Base nearly flat XXXVI. Euconia. 



I4f. Base rounded XXXVII. Eotomaria. 



5555. Aperture with slit aa'. 



aa'. Base flat or gently convex 15-f-. 



15 f. Slit short, upper sutural edges of whorls noded. 



XLV. Trepospira. 

 15-f-. Slit long, sutural edges not noded. 



XLIV. Euconospira. 

 aa'. Base strongly rounded, suture channeled. 



XLIII. Bembexia. 

 aa'. Base ventricose, suture not channeled. 



XLI. Mourlonia. 



19*. Whorls not embracing to angulation, spire scalariform a 7 . 



a'. With one or more strong carinae, the median one carrying the 



"band" 6666. 



6666. Aperture with notch only XXXI. Lophospira. 



6666. Aperture with slit bb 7 . 



bb 7 . Band simple XXXII. Schizolopha. 



bb'. Band crenulated XXXIV. Worthenia. 



2/ . With carinae between flat shoulder and large rounded body whorl. 



7777- 



7777. Aperture more or less drawn out anteriorly cc'. 



cc'. Shoulder flat, at right angle to axis of coiling. 



XXIX. Scalites. 

 cc'. Shoulder sloping, carrying the band. 



XXX. Ormospira. 

 7777* Aperture not drawn out, band only on last whorl. 



XXXIII. Phanerotrema. 

 15. Whorls rounded, globose, with vertical slit band near middle of whorl. 



XXXIX. Euryzone. 

 15. Whorls rounded and vertically compressed, slit band above deep suture. 



XL. Spiroraphe. 



15. Whorls rounded except for strong revolving spirals XLII. Gyroma. 



VII. Shell very obtuse (more than 120 ) to flat, or with sunken spire, the last 



whorl sometimes loosely coiled 16. 



16. With strong keel on upper side of whorl 20*. 



20*. Lines of growth not deflected by keel LVII. Euomphalus. 



20*. Lines of growth turning back over keel, forming distinct notch... b'. 



W. Keel low, within the periphery 8888. 



8888. Spire flat or sunken dd'. 



dd'. Whorls slowly enlarging, flat on under side. 



LII. Ophileta. 

 dd'. Whorls rapidly enlarging, under side concave. 



LVL Pleuronotus. 



