INDEX 



635 



anterior antennae, or antennules in, 



205. 

 Becki, 193, 201, 221. 



additional thoracic segments 



in, Walcott, 217. 

 mode of occurrence and struc- 

 ture and development of, 1 97. 

 endopodites of, 224. 

 eye-line in, 125, 126, 179. 

 eyes in, 126, 180. 

 facial sutures in, 125. 

 fringes on exopodites of, 218. 

 full number of segments in, 218. 

 further observations on ventral 



structure of, 203. 

 glabella in larval, 126, 180. 

 hypostoma of, 208. 

 legs of, 199. 

 mandibles of, 206. 

 maxillae of, 206. 

 metastoma in, 209. 

 morphology of, 213. 

 mouth, in, 209. 

 ontogeny of, 135. 

 organs in the median line of, 208. 

 paired biramose appendages in, 205. 

 uniramose appendages in, 205. 

 posterior antennse in, 206. 

 primitive characters of, 216. 

 protaspis in, 186. 

 respiration in, 218. 

 thoracic legs of, 207. 

 ventral structure of, 185. 

 Triceratops, 96. 



horns on head of, Marsh, 54. 

 Tridictyopus conicus, terminal spine in, 



44. 



Trigonactura triacantha, spines in, 44. 

 Trigonosemus, 246, 301, 306, 308. 

 Trilobita, J12, 114, 115. 



accelerated development of spines 



in, 22. 



a primitive type, 202. 

 classed with Aspidonia of the Crus- 

 tacea, 112. 

 evolution of, 31. 



geological development of,Packard, 

 98. 



distribution of, 133. 

 phyllopod affinities of, Bernard, 



210. 

 pleural spines in, 80. 



protective spines on, 56. 



pygidium of, 78. 



restraint of environment in, 39. 



spineless protaspis of, 19. 



spiniform structures in, 77. 



spiny forms of, 70. 



sub-class, 130, 131. 



tail spine in, 84. 



the earliest forms of Crustacea, 



Woodward, 184. 

 trilobite eggs, 169. 



head, composition of, Kingsley, 188. 

 larvae, variations in, 179. 

 trilobites, 214. 



affinities of, Bernard, Kingsley, 

 Woodward, 110. 

 to Entomostraca and Malacos- 



traca, 164. 

 an appendage to the Crustacea, 



Lang, 114. 

 antiquity of, 183. 



application of principles for ar- 

 rangement of families and genera 

 of, 125. 



arrangement of families of, 131. 

 blind, 153. 

 characters of, 116. 

 classed with arachnids, 109. 



with Crustacea, 109. 

 classification of, Barrande, 110. 

 Brongniart, 110, 111. 

 Burmeister, 111, 112. 

 Chapman, 113. 

 Corda, 111. 

 Dalman, 111. 

 Emmrich, 111, 112. 

 Gegenbaur, 114. 

 Goldfuss, 111. 

 Lang, 114. 

 McCoy, 111. 



Milne-Edwards, 111, 114. 

 Quenstedt, 111. 

 Salter, 110, 112, 132. 

 Walcott, 114. 



cranidium in, Bernard, 181. 

 description of elementary forms of, 



176. 

 development of, Barrande, Ford, 



Matthew, Walcott, 310. 

 discussions of order and families of, 



134. 

 dorsal shield of, Lang, 193. 



