92 



BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY. 



LIST OF SPECIES OF CTENACANTHUS OCCURRING IN THE 

 MISSISSIPPIAN SERIES (continued). 



Name of Species. 



6. C. sculptus St. J. and W. 



7. C. semicostatus (St. J. and W.) 



8. C. solidus Eastm 



9. C. spectahilis St. J. and W. . 



10. C. varians St. J. and W. 



11. C. venustus Eastm 



12. C. (?) burlingtonensis St. J. and 



13. C. gradocostatus St. J. and W. 



14. C. acutus Eastm 



15. C. cylindricus Newb. . . 



16. C. excavatus St. J. and W 



17. C. keokuk St. J. and W. . 



18. C. xiphias (St. J. and W.) 



19. C. costatus N. and W. . . 



20. C. deflexus St. J. and W. 



21. C. gemmatus St. J. and W. 



22. C. gurleiji Newb. . . . 



23. C. harrisoni St. J. and W. 



24. C. littoni Newb 



25. C. pellensis St. J. & W. . 



26. C. angidatus N. and W. . 



27. C. canaliratus St. J. and W. 



28. C. similis St. J. and W. . 



W 



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III. ON ACANTHODIAN REMAINS FROM THE COAL 

 MEASURES OF MAZON CREEK, ILLINOIS. 



Representatives of the Acanthodii are extremely rare in the Palaeozoic 

 rocks of North America, and the only species hitherto described are 

 restricted to the Devonian of the United States and Canada. If Ave 

 neglect the detached spines of Machseracanthus, and the indetermin- 

 able mass of scales described by Dr. J. M. Clarke^ as Acanthodes^T) 

 pristis.) American Acanthodians are limited to but one species each of 



1 Bull. U. S. Geol. Survey, No. 16 (1885), p. 42. 



