PLATE XIX. 



Streptelasma ijecta. 



Strombodes? rechis Hall. Geology of N. Y. Surv. Fourth Geolog. Dist., pp. 209, ^10. 1843. 

 Cyatliophyllum rectum Edw. -Haime. Polyp. Foss. des Terr. Palaeozoiques. 1851. 



Fig.s. ], 2. Lateral views of specimens of usual size and form, when not compressed. 



Fig. 3. View of a large specimen, showing the continuous line of the primary lamella of the fosset, 

 and the increase of the lamelke on each side. 



Fig. 4. Latei-al view of a specimen, showing the parallel striae, indicating the lamellse between two 

 of the primaries. 



Fig. 5. Longitudinal section of a small specimen. 



Fig. 6. Longitudinal section of a larger specimen, showing the edges of the lanielte in the middle, 

 and the sides of others toward the margin, with slight indications of transvei.se lines. 



Fig. 7. Lateral view of a curved specimen, showing a budding growth above. 



Fig. 8. Enlargement of a portion of the exterior, on a line with one of the primary lamellae, show- 

 ing the increase to be on one side. This is frequently the case with the lateral pri- 

 mary lamellse. 



Fig. 9. View of an unusually broad specimen. 



Fig. 10. An enlarged transverse section, just below the bottom of the cup, sljowing the extension 

 of the primary lamella to the center, and also the sparsely distributed interlameilar 

 cistose plates. 



Fig. IL An enlargement of a section lower down upon tlie coral, sliowing the thickening of the 

 lamehiB forming a solid central calhi.s. Tliis thickennig is often continued till the 

 lower part of the coral has become solid. 



Fig, 12. An enlargement of the interior of a cup, showing the curving of the lamehie and tlie 

 deep fosset extending towards one side. 



Fig. 13. View of a specimen from which the margin of the cup has been liroken. 

 Hamilton group, from various localities in Western New York. 



Streptelasma ungula ii. sp. 



Figs. 14, 15. Eight and left lateral views of two specimens, showing the increa,se of septal lines. 



Fig. 16. Dorso.-lateral view of anotlier specimen. 



Fig. 17. Longitudinal section, showing the thickened, almost solidified l.tmelte. 



Fig. 18. The concave side of a specimen o."' irregular growth, partially showing the characters of the 



cup. 

 Fig. 19. View of another specimen, .showing irregularities of growth. 

 Fig. 24. An enlarged transverse section, just below the base of the cup, showing the fosset on the 



right side. 



Amplexus Hamiltoxi.5; n. sp. 



Figs. 20, 22. Lateral views of specimens of different forms. 



Fig. 21. View of the largest specimen yet observed ; the upper part occupied by the cup is flattened 



and much broken. 

 Fig. 23. Longitudinal section, showing the tliin walls and broad transverse diaphragms, extending 



quite across the cup, which is comparatively destitute of radiating lamellae. 



From the Hamilton group. 



