Beyrich, E.

1846.--Untersuchungen ueber Trilobiten. 2. Stuck, p. 30, pl. 4, fig. 1c.

Billings, E.

1870.--Notes on some specimens of Lower Silurian trilobites. Quart.

Jour. Geol. Soc., London, vol. 26, pp. 479-486, pls. 31-32.

Abstract in Geol. Mag., vol. 7, p 291, and Nature, vol. 2, p. 94.

Brongniart, A.

1822.--Histoire naturelle des crustaces fossiles. Paris.

Brunnich, F. E.

1781.--Beskrivelse over trilobiten, en dyreslaegt og dens arter, med en ney arts aftegning. Nye Samlig of det Kong. Danske Vidensk.

Selskabs. Skriften, Copenhagen.

Burling, L. D.

1916.--Paedeumias and the Mesonacidae, with description of a new species, having at least 44 segments, from the Lower Cambrian of British Columbia. Ottawa Nat., vol. 30, pp. 53-58, pl. 1.

1917.--Was the lower Cambrian trilobite supreme? Ibid., vol. 31, pp. 77-79, text figs. 1-2.

Burmeister, H.

1843.--Die Organisation der Trilobiten. Berlin.

1846.--The organization of trilobites, deduced from their living affinities. Eng. translation, Ray Society, London.

Calman, W. T.

1909.--Crustacea, in "A treatise on zoology," edited by Sir Ray Lankester. London.

1919. Dr. C. D. Walcott's researches on the appendages of trilobites.

Geol. Mag., dec. 6, vol. 6, pp. 359-363, pl. 8, text fig. 1.

Carpenter, G. H.

1903.--On the relationships between the cla.s.ses of Arthropoda. Proc.

Roy. Irish Acad., vol. 24, pp. 320-360, pl. 6.

Castelnau, F. DE.

1843.--Systeme Silurien de l'Amerique Septentrionale, p. 15, pl. 2, figs. 1, 4.

Clarke, J. M.

1888.--The structure and development of the visual area in the trilobite, _Phacops rana_ Green. Jour. Morph., vol. 2, pp. 253-270, pl. 1.

Crampton, G. C.

1916.--The phylogenetic origin and the nature of the wings of insects, according to the paranotal theory. Jour. New York Entomol. Soc., vol. 24, pp. 1-39, pls. 1, 2.

1919.--The evolution of the arthropods and their relatives, with especial reference to insects. Amer. Nat, vol. 53, pp. 143-179.

Dalman, J. W.

1826.--Om Palaeaderna eller de s kallade Trilobiterna. Stockholm, Acad. Handl., pp. 113-152, 226-294.

1828.--Ueber die Palaeaden, oder die sogennanten Trilobiten. Nuremberg.

Dana, J. D.

1871.--On the supposed legs of the trilobite, _Asaphus platycephalus_.

Amer. Jour. Sci. (3), vol. 1, pp. 320-321, 386; Ibid. (3), vol.

3, 1872, pp. 221-222. Also printed in Ann. Mag. Nat. Hist, vol.

7, 1871, pp. 366, 451.

Dekay, J. E.

1824.--Observations on the structure of trilobites, and description of an apparently new genus. Ann. Lye. Nat. Hist. New York, vol. I, p. 174, 2 pls.; Isis (Encycl. Zeit.), Oken, 1825 and 1832.

Dollo, L.

1910.--La paleontologie ethologique. Bull. Soc. Beige de Geol., Pal., et d'Hydrol., vol. 23, pp. 377-421, figs. 1-13, pls. 7-11.

Eichwald, E. VON.

1825.--Geognostico-zoologicae per Ingriam Marisque Baltici Provincias nee non de trilobitis observationes. Section 45.

1858.--Beitrage zur geographischen Verbreitung der fossilen Thiere Russlands. Bull. Soc. Imp. des Natural, de Moscou, vol. 30, 1855-1857, p. 204.