IXDKX. 



Systematic descriptions (coiitiniictU ' 



Mixosauridae of uncertain position. 148. 

 .\lixosaurus( ?) atavus group, 90. 

 Mixosaurus, 94. 



Mixosaurus cornalianus, 95. 

 Shastasaurus, 137. 



Shastasaurus alexandrae, 142. 

 Shastasaurus altispinus, 144. 

 Shastasaurus careyi, 145. 

 Shastasaurus osrnonti, 138. 

 Shastasaurus pacificus, 143. 

 Toretocnemus, 127. 



Toretocnemus californicus, 128. 

 Temporal bar, 24. 

 Thalattosaurus, 62. 

 Toretocnemus, 50, 51, 127. 

 Toretocnemus californicus, 49, 55, 66. 128 ; pi. 14. fig. 



4. 

 Trachyeeras beds of American Upper Triassic, 128, 



129, 137, 142. 



Tubingen, Geologisch-ilineralogisches Institut, collec- 

 tions of, 12. 



rpper Triassic of America, 15; of California, pi. 1, 

 figs. 2-3; characteristic species, 17; of Kurope, 

 14; of France, 14. 

 Variation in the Ichthyosaiuia, 79. 

 Vertebrae, general structure. 29. 

 Atlas and axis, 37. 

 Caudal fin, 39. 

 Korm of centra, 30. 

 Hypocentral elements, .'ill 

 Neural arches, 33. 

 Vertebral formula, 29. 

 Wellendolomit, 9. Ill, 12. 13. 

 Wemple, Miss K. M., cited, 17, 18. 



West Humboldt Kange, Nevada, pi. 1, fig. 1; charac- 

 teristic species of Trias, 18, 104, 150. 

 Wheeler, Benjamin Ide, acknowledgment of assistance, 



6. 



\Villiston, S. W., cited, 77. 

 Woodward, A. Smith, acknowledgment of assistance. 



<!, 77. 



Yakowlew, N., cited, 11, 14, 50, 53, 98, 138, 149, 150. 

 Zurich, Polytechnikum, collections of, 12, 13, 49. 91. 

 Zygapophyses, 36. 



[196] 



