PLATE 45. 



Page 



Figs. 1-6. Khynchospira lepida 27(> 



I. A ventral view, natural size. 



2-4. Dorsal, ventral and proHle views of a specimen of the prevailing form; enlarged to two 



diameters. 

 6. Dorsal view of an individual of an elongate form, in which the sinus of the dorsal valve 



is more strongly marked than usual (enlarged). 



6. A still further enlargement of the rostral portion of fig. 2, for the purpose of showing delti- 



dial plates, foramen, etc. (The lithographer has unfortunately omitted the lines marking 

 the limits of the deltidial plates.) 



Figs. 7 - 15. Thematospira qibbosa 272 



7, 8. Dorsal and ventral views of a small specimen. 

 9. Dorsal view of a specimeu of medium size. 



10-14. Dorsal, ventral, cardinal, i>rotlle aud front views of a full grown individual. 



15. Kniargement of the cardinal portion of a dorsal valve of this species, showing the peculiar 



cardinal process aud slender mesial septum. 



Figs. 16 - 32. Thematospira hirsuta 274 



16. A dorsal view of an individual, from the Cornlferous limestone of Louisville, Ky. 



17 - 19. Dorsal views of specimens, showing variations in size and development of the mesial 

 fold and sinus; tig. 19 being essentially destitute of these features. 



20. Ventral views of a large individual. 



21, 22. Dorsal and profile views of a round and gibbous specimen. 



28-27. Dorsal, ventral, profile, cardinal and front views of a full grown individual. 



28. Interior of a dorsal valve. 



29. An enlargement of the upper part of fig. 28, showing cardinal process, dental sockets, and 



ba.ses of the crura. 



30. Interior of a ventral valve. 



81. Enlargement of the beak of fig. 30, showing the teeth, false area and foramen. 



82. An individual having the greater part of the dorsal valve removed, showing the internal 



spires and bases of the crura. 



Figs. 33-57. NucLEosPiRA concinna 279 



88. Cast of a ventral valve, from the Schoharie grit. 



34, 86. Dorsal and profile views of a specimeu, from the Upper Ilelderberg limestone. 



86, 37. Dorsal views of small individuals, from the Hamilton group; the latter preserving the 



fine huir-like sela; on a part yf the shell. 

 88, 39. Dorsal and profile views of a speoinum where the valves are of nearly equal depth. 

 40,41. Dorsal views of flattened specimens which preserve the fine seta; very beautifully. 

 42-40. Dorsal, ventral, profile, cardinal and front views of a large aud well preserved si>eci- 



men where the valves are of unequal depth. 

 47, 48. Interior aud profile views ot a dorsal valve, showing the size and form of the cardinal 



process. 

 49. Enlargement of the cardinal process, showing the small elevated pad for the attachment of 



the cardinal nmscles, the dental sockets, and the points for the attachment of the crura. 

 60. Interior of a ventral valve. 



51. Enlargemcut of the beak of the ventral valve, showing the teeth and false area. 



52. View of a s|K!ciraen showing the spires. 



&i, 57. The internal cast of a dorsal and a ventral valve; enlarged to two diameters. 



54. The cast of ft ventral valve of the natural size. 



55, 56. The caats of dorsal valves, of the natural size, showing some variation in the form and 



markings. 

 68. Enlargement of the surface, showing the fine seta:, and the bases of others which have 

 been broken away, giving a minutely pustulose surface. It is this feature which 

 gives the apparent punctate texture to the surface of these shells. 



