40 CALIFORNIA ACADEMY OF SCIENCES. 



The author remarks iu regard to Calymene spinifera: "Among the 

 specimens of Lower Silurian fossils of Missouri in the collection of my 

 friend J. N. Nicollet, Esq., I noticed the tail of this curious trilobite, which 

 has on the back of one of the articulations of the middle lobe an erect 

 curved spine, curved towards the caudal extremity, and more than one- 

 third of an inch iu length." 



Conrad's species should replace Cyphaspis girardcatiensis: Shumard, 

 ISoo. 



Observations on tlie lead-bearing limestone of 



Wisconsin, and descriptions of a new genus of Trilo- 

 bites and fifteen new Silurian fossils. 



In Proc. Acad. Nat. Sci., Phila., vol. 1, 1843, p. 329. 

 Thaleops n. g., T. ovatus n. sp. 



Corda (A. J. C.) and Hawle (Ignaz). Prodrom einer 

 Monographie der bohmischen Trilobiten. 



In Abhaudl. biihm. Gesell. Wiss., Prag, vol.5, 1847, pp. 129-292, 7 pis. 



This work is generally attributed to A. J.C. Corda. The 58 new genera 

 described in this work are arranged by Joachim Barrande, Systeme silurien 

 du centre de la Bohi^me, vol. 1, p. 39, as follows: 



I. Division-. Telejueides. 



1. Phlvsacium 1 „ , i i t. 



•' y r= Hydroceiihalus Barr. 



2. Phai^optes J 



3. Crithias \ 



4. Tetracnemis 



5. Goniacanthus 



6. Enneacnemis 



7. Acanthocnemis \ ci -d 



, = Sao Barr. 



8. Acanthogramma/ 



9. Endogramma 



10. Micropyge 



11. Selenosema 



12. Staurogmus / 



V = Arionellus Barr. 



14. Agraulos J 



15. Conocoryphe ) 



16. Ptychoparia > = Conocephalus Zenk. 



17. Ctenocei^halus \ 



18. Selenopeltis = Acidaspis Murcli. 



19. Polytomurus =: Dionide Barr. 



20. Tetrapsellium = Trinucleus Lhwyd. 



21. Phalacroma = Aguostus (in part) Brong. 



22. Seleuoptychus = iEglina Barr. 



23. Mesospheniscus r=: Aguostus integer Beyr. 



