PLATE 46. 



p»g« 



Figs. 1-4. AtH YRI8 VITTATA 289 



1-4. Dorsal, ventral, proftle and front views of a specimen from tlie Falls of the Ohio, pre- 

 senting the ordinary characters of the species. 



In the description of the internal spire-s of this .species, page 290, the letter h is used to indi- 

 cate the junction of the intercalated lamellsc, hui was accidently omitted from the 

 figure on page 289. The corrected figure is therefore inserted in this place. 



Figg. 5-31. Athtris spirifekoides 285 



5. A small individual without mesial fold or sinus. 



6, 7. Views of small specimens, of ordinary form, in which the fold and sinus are partially 



developed. 



8 A larger specimen, showing a strongly lamellose surface. 



S. Dorsal view of a laterally expanded specimen. 



10, 11. Dorsal views of rounded gibbous forms. 



12. Dorsal view of a specimen of the ordinary form and of medium size. 



18. Dorsal view of an extremely broad individual. 



14. Front view of specimen, fig. 13, showing extreme elevation in front. 



15-19. Dorsal, ventral, cardinal, front and profile views of a well defined and moderately 

 gibbons form. 



20-24. Dorsal, ventral, cardinal, front and profile views, of a rounded, gibbous and thickened 

 shell. 



26. Dorsal view of a large specimen, showing a strongly lamellose surface. 



26, 27. Interiors of a dorsal and a ventral valve, showing hinge structure and muscular im- 

 pressions. 



28, 29. Dorsal and ventral views of an internal cast of this species, from the Hamilton group, 

 Hardy county, Va., showing very distinctly the impressions of the muscular markings. 



80. Ventral view of a cast from the same formation in New York, showing tlie muscular and 



vascular markings in a still more perfect state. 



81. A specimen, which has been cut to show the spires. The intercalated lamellte are not seen 



in this view. (See page 284 and plate 47, fig. 8.) 



