PLATE 18. 



Figs. 1 and 2. Aoi.e ? pahva 29(5 



l,<r. Upper sido of ;iu internal cast, natural size, of type-specimen. 

 1, b. A lateral view of same. 

 1, c. Interior of the shell of same. 

 2. Internal cast, magnified, to show the small, horseshoe-shaped, muscular scar. 



Fig. 3. AcMiEA occidentals 293 



3, a. An internal cast, natural size, showing the muscular scar anil obscure radiating lines of 

 the interior. 



3, 6. A side view of same. 



3 c. An upper-side view of internal cast, magnified, to show more clearly the muscular scar and 

 other markings. 

 Fig. 4. Anisom.yon alveolus 292 



4, a. An internal cast, with some remainiug portions of the shell around the margins and the 



peculiar muscular scar seen nearly inclosing the apex (type-specimen). 



4, b. A side view of same. 



Fig. 5. Anisomyon fatklliformis 290 



5, a. A side view of a testiferous specimen, showing the immediate minute apes abruptly 



curved backward. 

 5, b. An anterior view of same. 



5, c. The type-specimen, with a part of the thin shell removed, to show the peculiar muscular 



scar with its characteristic break on the right posterior side. 

 5, ' . Another more elliptic form, possibly belonging to this species. 

 5,/. An upper view of a large internal cast, showing muscular scars, etc. 



FlGS. :">, (7, AND C. ANISOMYON SUBOVATUS 291 



5,(7. A side view of the type-specimen, consisting of an internal cast, with the immediate 

 apex broken away. 



6, An upper view of same. 



Fig. 7. Anisomyon Siiumardi 289 



7, a. A side view of the testiferous type-specimen, with tie apex wanting. 

 7, b. An upper view of tho same. 



7, c. An anterior view of same. 

 Fig. 8. Anisomyon sexsulcatts 293 



8,0. An imperfect internal cast, side view (type-specimen). 



H, b. An upper-side view of same, showing obscurely the muscular scar. 

 Fig. 9. Anisomyon boreai.is 288 



9, a. An upper-side view of an imperfect, partly testitereous specimen, with the little apex 

 broken away. 



9, b. A side view of the same, the apex being restored in outline. 



9, c. An anterior view of same. 



9,(7. An upper view of a larger internal cast, on which the muscular impression is obsolete. 



9, e. A side view of same. 



Fig. 10. II AMINE A ? SUBCYLINDKICA 272 



10, a. An aperture view of the type-specimen, consisting of an internal cast, broken so as to 



give an unnatural truncated appearance to the columella and lower part of the lip. 

 10.7). An epposite view of the same. 



FlGS. 11 AND 12. 1 1 AM IN EA 1 OCCIDENTALIS 271 



11,0. An internal cast, natural size. 



11, 6. An aperture view of another internal cast, broken about the base of the aperture (type- 



specinien). 



12,«. Another cast, also with lip broken. 



12, 7). The same, magnified ; the truncated appearance of the columella being due to a break. 

 Fig. 13. Dentai.ium gracile. 206 



13, a. A specimen, witli the larger part broken away. 



13, b The larger part of another specimen, on which the longitudinal stria' are nearly obsolete. 



13, c. Surface-markings, from lig. 13, a, magnified. 



13,<7 An <>nt 1 mi- .seel ion ot 'the larger cud of the Specimen, represented by fig 13. 6. 



I'n.. 14. Km m.is ' I'.u i'i:i:iri.A 209 



A part of the shell, natural size (typo-specimen). 



