INDEX 



637 



regressive, 6. 

 restrictions of, 7. 

 tendency of, 6, 

 variations in Achatinella and All&rchestes, 



36, 37. 



Vella, spiniform branches of, 75. 

 Verneuilina spinulosa, spines in, 44. 

 Vernon, H. M., reproductive divergence, 



37. 



Verrill, A. E., Achatinellae, 36. 

 cannibalistic selection, 57. 

 characters in appendages of Tri- 



nucleus, 225. 

 importance of tabulas in a natural 



classification of corals, 427. 

 vertebrae, spines of, 9. 

 vertebrates, hornless young of horned, 



19. 

 Verworn, development of extinct Ostra- 



coda, 310. 

 vitality, ebbing, Geddes, 12. 



W 



Waagen, W., classification of Brachiop- 



oda, 242, 290. 



septal and dental plates in the 



terebratuloids, 297. 



Wachsmuth, C., and Springer, F., 



development of tubercles of Crinoidea 



and Asteroidea into spines, 50. 



spines on ventral sacs of Crinoidea, 



45. 



Walcott, C. D., additional thoracic seg- 

 ments in Trlarthrus Becki, 217. 

 biramous appendages in Triarthrus 



200. 

 casts of pedicles of fossil Lingulae 



and Eichwaldia, 257. 

 classification of trilobites, 114. 

 development of trilobites, 310. 

 metamorphoses of trilobites, 166. 

 mouth in Calymmene, 209. 

 possible trilobite eggs, 169. 

 young of Olenellus asaphoides, 1 78. 

 Waldheimia,4ll. 

 bicarinata, 413. 

 Mown, 413. 

 recurved loop in, 413. 

 septigera, 297. 



Wallace, A. R., on the origin of xeroph- 

 ilous plants, 74. 

 protective horns in males of Copri- 



dse and Dynastidse, 60. 

 Whitfieldella, absence of embryonal 

 sinus in, 388. 



nitida, 351, 352, 356, 373, 378, 392. 

 discussion of, 374. 



early stages of growth in, 373. 

 tumida, 377. 

 Whitfiddia, 377. 

 Williams, H. S., variations in stock of 



Atrypa reticularis, 25. 

 Woodward, H., affinities of trilobites, 

 110. 



Trilobita the earliest forms of Crus- 

 tacea, 184. 



Xanthidium armatum, spine growth 



from frustule of, 43. 

 Xiphogomium, 148. 

 Xiphosphcera polios, spines in, 48. 

 Xylotrupes gideon, horns in, 60. 



Youngia, 155, 156. 



Zacanthoides, 113, 142, 143, 144. 



pygidium in, 143. 



Zaphrentis spinulosa, spinules in, 50. 

 Zellania, 246, 300, 304, 308. 



schizolophus stage in, 279. 

 Zitta, branches of, transformed into 



spines, 74. 



Zittel, K. A. von, classification of 

 articulates, 112. 



of Trilobita, 112,132. 

 historical review of trilobites, 111. 

 oldest species of Spondylus, 23. 

 terminal spine in Nasellarian Radi- 



olaria, 43. 

 zoe'a of common crab, 56. 



of Decapoda, spines in, 57. 

 Zoic maxima, Gratacap, 35. 

 zugolophus stage, 281, 284. 



