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IX.— The Trilohitca of the Bokkevdd Beds.— By Philip Lake, 

 M.A., F.G.S. 



(Plates XXIV.-XXVIII.) 



INTKODUCTION. 



The fullest account of the trilobites of the Bokkcveld Beds of South 

 Africa which has yet appeared is that which was published by 

 Salter" in 1856 as an appendix to Bain's paper " On the Geology 

 of South Africa," and since that time but little has been added to 

 our knowledge of the South African forms. Dr. Woodward i in 

 1873 described a remarkable species from the Cock's-comb Moun- 

 tains, and Dr. Freeh I in 1897 figured a Homalonotiis which he 

 believed to be new ; but with these exceptions I am not aware that 

 anything has been added to Salter's original account. 



The very fine collection placed at my disposal by the Director of 

 the Survey includes specimens of all the known species from South 

 Africa, and the perfect nature of much of the material has enabled 

 me in some cases to correct and amplify the descriptions of my 

 predecessors. The collection includes also a number of new forms, 

 of which by far the most remarkable is the gigantic Homalonotim 

 colossus, sp. nov. 



The account which follows is based chietiy upon this collection, 

 but I have also examined the specimens in the British Museum and 

 in the Museum of the Geological Society of London. All of Salter's 

 types, with one exception, are in one or other of these Museums. 



The following species may be distinguished and are here 

 described : — 



* Trans. Geol. Soc, ser. 2, vol. vii., p. 21.5. 

 t Quart. .Journ. Geol. See, vol. xxix., p. 31. 

 J Lethaea geognostica, Th. i., Bd. 2, Lief, i., p. 218. 



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