LARVAL STAGES OF TRILOBITES 195 



taspis more nearly represents the primitive ancestral larval 

 form for the class, and approximates the protonauplius. 



References. 



1. Balfour, F. M., 1885. A Treatise on Comparative Embryology, 



memorial edition. 



2. Barrande, J., 1849. Sao hirsuta Barrande, ein Bruchstiick aus dem 



" Systeme silurien du centre de la Boheme." Neues Jahrbuch fur 

 Mineralogie, etc. 



3. 1852. Systeme silurien du centre de la Boheme, l er 



partie. 



4. Beecher, C. E., 1893. Larval forms of Trilobites from the Lower 



Helderberg Group. Amer. Jour. Sci. (3), vol. xlvi. 



5. 1893. A Larval Form of Triarthrus. Amer. Jour. Sci. (3), 



vol. xlvi. 



6. 1893. On the Thoracic Legs of Triarthrus. Amer. Jour. 



Sci. (3), vol. xlvi. 



7. 1894. On the Mode of Occurrence, and the Structure and 



Development of Triarthrus Becki. American Geologist, vol. xiii. 



8. 1894. The Appendages of the Pygidium of Triarthrus. 



Amer. Jour. Sci. (3), vol. xlvii/ 



9. 1895. Further Observations on the Ventral Structure of 



Triarthrus. American Geologist, vol. xv. 



10. 1895. Structure and Appendages of Trinucleus. Amer. 



Jour. Sci. (3), vol. xlix. 



11. Bernard, H. M., 1892. The Apodidse. A Morphological Study. 



Nature Series. 



12. 1894. The Systematic Position of the Trilobites. Quar. 



Jour. Geol. Soc. London, vol. 1. 



13. Callaway, C., 1877. On a new area of Upper Cambrian rocks in 



South Shropshire, with a description of a new fauna. Quar. Jour. 

 Geol. Soc. London, vol. xxxiii. 



14. Clarke, J. M., 1894. The Lower Silurian Trilobites of Minnesota. 



In advance of vol. iii, Pt. ii, Geol. and Nat. Hist. Surv. of Minn. 



15. Glaus, C., 1876. Untersuchungen zur Erforschung der genealo- 



gischen Grundlage des Crustaceen-Systems. 



16. 1885. Neue Beitrage zur Morphologic der Crustaceen. Arb. 



zu. Inst. Wien, vi. 



17. Corda, A. J. C. [and I. Hawle], 1847. Prodrom einer Monographic 



der bomischen Trilobiten. Abhandl. bohm. Gesell. Wiss., Prag, 

 vol. v. 



18. Dohrn, Anton, 1870. Untersuchungen iiber Bau und Entwickelung 



der Arthropoden, Zeitsch. fur Wiss. Zool., Bd. XXI. 



