204 CALIFORNIA ACADEMY OF SCIENCES [Pkoc. 4th Ser. 



Later Visits 220 



Darwin, 1835 220 



"Venus," 1838 „ 226 



"Herald," 1846 226 



"Eugenie," 1852 226 



Dr. Habel, 1868 226 



Hassler, 1872 226 



Cookson, 1875 226 



"Challenger," 1875 228 



"Albatross," 1888 and 1891 228 



Baur and Adams, 1891 228 



Webster-Harris, 1897 228 



Snodgrass and Heller. 1898-1899. 234 



Captain Noyes. 1900 237 



Beck, 1901 and 1902 237 



Academy Expedition, 1905-1906 241 



Present Status 243 



Number of Races 243 



Living 243 



Extinct 243 



Systematic Account 244 



1. Nomenclature 244 



Names proposed 244 



Discussion of names 244 



Testudo nigra 244 



calif orniana 245 



elephantopus 245 



nigrita 249 



planiceps '. 251 



ephippium 251 



microphyes 252 



vicina 253 



galapagoensis 255 ' 



gUntheri 256 



wailacei 257 



Application of names 259 



2. Description 259 



Characters available for classification 259 



The shell 259 



Variation in plates 260 



Variation in shape 289 



Measurements used 289 



Charts of each measurement 289 



Table of averages 289 



extremes 289 



Differences with age 289 



sex '. 289 



distribution 290 



