PLATE 60. 



p»g« 



Figs. 1-4. Terebratula lens 386 



1-8. Dorsal, ventral and prolUo viows of a specimen of the ordinary size and form. 

 4. Dorsal view of a larger but somewhat distorted specimen. 



Figs. 6 - 10, 68. Terebratula sullivanti 387 



6-7. Dorsal, ventral and protllc views of a small specimen of the species, from Columbus, Ohio. 



8. Dorsal view of an imperfect specimen, from Cuyuga, Canada West. 



9, 10. Dorsal and ventral views of a large imperfect specimen, from the same locality as the last. 

 68. Enlarged dorsal view of a specimen from Cayuga, C. \Y., showing the reversed loop. This 



feature, so far as yet ascertjiiiied, is peculiar to this species, and may possibly bo due to 

 accident in the specimen e.\amined. 



Figa. 11 - 16. Terebratula harmonia 388 



11. Dorsal view of a young individual. 



12. Ventral view of a larger and broader form, from Cayuga, ^. W. 



13. The dorsal side of the same specimen cut down to show the loop. 



14-16. Dorsal, ventral and protile views of a more elongated specimen. This, and specimen 

 fig. 11, are from the Falls of the Ohio. 



Figs. 17 - 2.5, 66, 67. Terebratula ikeminoeri 389 



17 - 19. Dorsal, ventral and profile view of a large rotund form, from Hamburgh, N. Y., on the 

 shore of Lake Erie. 



20, 21. Dorsal views of two specimens from New York, one of them showing an emargination 

 in front, and the other rounded ; enlarged to two diameters. 



22 - 24. Dorsal, ventral and profile views of a specimen from Michigan, showing a distinct emar- 

 gination in front and a sinus on the ventral side; enlarged to two diameters. 



25. Dorsal view of another individual from Michigan, which is destitute of sinus or emargina- 

 tion; enlarged to two diameters. 



66, 67. Ventral and profile views of the loop of this species; enlarged fVom a specimen, ft-om 

 Michigan. 



Figs. 26 - 28. Terebratula elia 390 



26-28. Dorsal, ventral and profile views of the specimen described. 



Figs. 29 - 31. Terebratula jucunda 390 



29-31. Dorsal, ventral and profile views of the specimen described. 



Figs. 32 - 37, 71. Terebratula linckl.«ni var 418 



82. Dorsal view of a young shell of this species. 



83 -35. Dorsal, ventral and profile views of a full grown shell. 



86, 37. Dorsal and profile views of a more gibbous form. 



71. Ventral view of the loop, showing the disconnection at the anterior extremities. 



Fig8.38-44. Terebratula NAVioBLLA 391 



88-40. Dorsal, ventral and profile views of a large specimen of the species. 



41. Dorsal view of a .smaller individual. 



42-44. Dorsal ventral and profile views of a more slender specireen of the species. 



Figs. 45 - 48. Terebratula Ontario 418 



45. Dorsal view of a round symmetrical specimen. 



46-48. Dorsal, ventral and profile views of a larger and slightly longer specimen. 



Fig8.49-65. Terebratula LiNCKL.a;Ni 397 



(This species referred with doubt to the Genus Crtptoneli.a on page 897, has proved to be a 



Tekebbatula.) 

 49. Dorsal view of a young specimen. 



60-52. Dorsal, ventral and profile views of a larger specimen. 

 68-65. Dorsal, ventral and profile views of a more gibbous specimen, which is much thickened 



on the front margin. 

 66, 57. Ventral and profile views of a small and very gibbous individual with strong varices of 



growth. 



68, 59. Dorsal and ventral views of a young individual having a much broader or less elongated 



form than usual. 

 60. Dorsal view of a larger specimen of the same fortn with the last. 

 61-68. Dorsal, ventral and profile views of a full grown specimen of the broad form. 

 64, 65. Dorsal and ventral views of a cast of this s|)ccies, showing the muscular lines and also 



the cavities near the buak left by the removal of the dental lamellse. 



Figs. 69, 70. Terebratula simulator 391 



69, Dorsal view of a specimen which has been out to show the loop; enlarged to two diameters. 



70, Profile view of the loop, showing the long crural proo.jsses; enlarged. The connexion at 



the anterior end is theoretically restored, but may have been connected during life by a 

 ligament only. 



