220 PALEONTOLOGY 



SWINNERTON, H. H. (i) Classification of Trilobites, 

 Geol. Mag., dec. 6, vol. ii. (1915). (2) Facial Suture of 

 Trilobites, Geol. Mag., dec. 6, vol. vi. (1919). 



VOGDES, A. W. Classed and Annotated Bibliography 

 of Palaeozoic Crustacea, California Acad. Sci., Occ. Papers, 

 iv. (1893), with Supplement in Proc. California Acad., 

 vol. v. (1895). Invaluable for all research work on 

 Trilobites. 



WALCOTT, C.D. Cambrian Geology and Palaeontology, 

 Smithsonian Misc. Coll., vols. liii. (1910), Ivii. (1914) Ixiv. 

 (1916), Ixvii. (1918). 



