PLATE CXVI. 



CORNULITES PROPRIUS. Hall, 

 l'age 19. 



Fig. 1. A single young individual attached to the shell of Slrophostylus cyclostomus. The transverse an- 

 notations are very conspicuous, but the longitudinal striae are scarcely developed. 



Fig. 2. A group ef three individuals in the same stay.- of development, attached to the shell of Platyostoma 

 Niagan asi . 



Fig. 3. A group of young individuals attached to a gastropod shell and exhibiting an irregular]} circular 

 arrangement in their mode of growth. 



Fig. 4. A young individual attached for its entire length to a branch of Trematopora. 



Fig. 5. A later stage of growth, in. which the transverse annulations are less regular and the longitudinal 

 stria: distinctly visible. This tube is attached to a fragment of Idehenalia, and retains its in- 

 curved apical portion. 



Fig. 6. A specimen in a similar stage of growth, also retaining the apical porti f the tube. 



Fig. 7. A somewhat crushed individual attached to the shell of Rhyncfumella Stricklandi. 



Fig. 8. Two large tubes attached by their apices to a shell of Platystoma Niagarense, leaving the bodj 

 of the tube nearly free. In this stage of development the annulations are obsolescent and less 

 regular, and the longitudinal stria- conspicuous. The terminal portion of left tube is restored 

 in the drawing. 



Fig. 9. A somewhat larger individual attached to the calyx of Eticalyptocriniis erassus. The attached 

 portion of the tube is flattened and united 1>\ nearly its entire width to the crinoidal plates. 

 The annulations are obsolete. 



Fig. 10. A very large individual, showing the characters of the fully developed form, in which the annula- 

 tions have become very irregular and obsolescent, and the longitudinal stria- correspondingly 

 prominent. 



Fig. 11. A somewhat crushed specimen, showing very irregular growth, a strongly striated surface, and 

 the repair of injuries received during the life of the animal. 



Fig. 12. Another specimen, showing similar characters. 



Fig. 13. An enlargement of the surface of the last .specimen, showing the character of the longitudinal stria' 

 and the abrupt change at one of the concentric ridges. 



Fig. 14. An enlarged longitudinal section of a young tube, in which the annulations are well developed J 

 showing the thickness of the" vesicular wall. 



Fig. 15. A longitudinal section of a larger individual, natural size, showing the thickness of the vesicular 

 wall and the annular ridges of the internal surface. 



Fig. 16. A longitudinal section of a large tube, in which the vesicular wall is quite thin, and the inner 

 surface strongly annulated. 



Fig. 17. A longitudinal section of a large tube, the vesicular walls of which are verj thick. 



Fig. 18. An enlargement of a pertion of the left wall, represented in tig. 17. showing more distinctly the 

 vesicular structure of the walls and the formation of a layer of vesicular tissue over the annu- 

 lations of the internal surface. 



Fig. 19. A transverse section of a tulie. natural size, showing the thickness of the walls. On the upper 

 margin, and on the right hand lower margin are intervals where the cellular tissue has not 

 been developed. 



Fig. 20. A similar transverse section, enlarged. 



Fig. 21. A still greater enlargement from the same specimen. 



t The specimens illustrated in the preceding figures 1-21 are all from the 

 Niagara group. Waldron, Indiana. 



Cornulites Clintoni. Hall. 



Page 18. 

 Fig. 22. An internal cast of a tube, showing impressions of the strong annulations upon the inner surface. 

 Clinton group. Near Lockport, Niagara county. 



