3S6 J. D. Tothill — The Ancestry of Insects. 



clear that they reached their stage of maximum deployment 

 in the Mesozoic era and that they are now in a condition of 

 decline. 



I wish finally to express my appreciation of the kindly help 

 and criticism given during the preparation of this paper by 

 Dr. Percy E. Raymond in the field of paleontology ; by Dr. 

 It. Y. Chamberlain in connection with Chilopod structures and 

 embryology ; and by Dr. Win. M. Wheeler in the field of 

 insect embryology. 



Literature cited. 



Beecher, Charles Emerson , 



1895. The larval stages of trilobites, Am. Geol., xvi, 166-197, pis. 

 VIII-X. 



1896. The morphology of Triarthrus, plate IX, this Journal (4), 1, 

 251 256, pi. VIII 

 Carpenter, George H. 



1903. On the relationships between the classes of the Arthropoda. 

 Proc. Eoy. Irish Acad., pp. 320-360. 

 Claypole, Agnes Mary 



1898. The embryology and oogenesis of Anurida maritima. Journ. 

 Morph., vol. xiv, No. 2, pp. 219-290. 



Folsom, Justus Watson 



1899. The segmentation of the insect head. Psyche, August, '99, 

 Cambridge, Mass. 



1900. The development cf the mouthparts of Anurida Guer, Bull. 

 Mus. Comp. Zool., xxvi, No. 5, pp. 87-157. 



Handlirsch, Anton 



i 1908. Die fossilen Insekten und die Phylogenie der recenten Pormen, 

 Leipzig. 

 Heymons, Richard 



1901. tjberdie Biologieund Fortpflanzung der Scolopender, p. 1-234, 

 plates I-Y1II. Zoologica Heft 33, Dreizehnter Band, Zvveite 

 und dritte Lieferungen. 



Jaekel, Otto 



1901. Beitrage zur Beurtheilung der Trilobiten, Theil 1, tafel. IV- 

 VI. Zeitschr. d. deutsclu geol. Gesellsch., liii, Heft 1. 

 Janet, Charles 



1899. Essai sur la constitution morphologique de la tete de l'insecte 



par Paris, Carre et C. Naud. 



Kingsley, J. S. 



1894. The classification of the Arthropoda, Am. Nat., pp. 118-135. 



Lindstrom, G. 



1901. Researches on the visual organs of Trilobites ... 6 plates. 



Kongl. svenska Vetenskaps-akademiens Handlingar, xxxiv, 



No. 8. 

 Raymond, Percy E. and Barton. Donald C. 



1913. A revision of the American species of Ceraurus, 2 pis., Bull. 

 Mus. Comp. Zool. Harvard, vol. liv, No. 20. 



Raymond, Percy E. 



1914. Notes on the ontogeny of Issotelus gigas Dekay, Bull. Mus. 

 Comp. Zool., vol. lviii, No. 5, Cambridge, Mass. 



Ruedemann, Rudolph 



1916. On the presence of a median eye in trilobites, Proc. Nat. Acad. 

 Sci., vol. ii, p. 234. 



