600 



INDEX 



free segments in, 136. 



free tlioracic segments in, 1 83. 



generic names for, Barrande.Corda, 



136. 

 hypostoma in, 13.5. 

 nudus, 177. 



youngest forms of, 176. 

 pleural spines in, 80. 

 pygidium in, 135. 

 rex, 177. 



youngest forms of, 176. 

 series of, in Museum of Compara- 

 tive Zoology, 134. 

 in National Museum, 134. 

 Agraulus, 142, 145. 

 Agulhasia, 291, 307. 



hinge-plates and muscular fulcra in, 

 305. 

 Allorchestes armatus in Lake Titicaca, 

 Faxon, 65. 

 evolution of, in Lake Titicaca, 



Faxon, 36. 

 variations in, 37. 



wonderful specific development of, 

 in Lake Titicaca, Faxon, 65. 

 Alveopora, 428. 

 Amhoccelia, 245. 



ammonites, retrogression in Creta- 

 ceous, 91. 

 Ammonoidea, chief spiny forms of, 96. 

 geological development of, Packard, 



98. 

 radicle types in, 95. 

 Amceha proteus, form of, 27, 28. 

 Amabina, 43. 

 Amphiclina, 245, 270. 

 Amphigenia, 245. 



dorsal beak in, 264. 

 Amphion, 155, 156. 

 amphipods found in lakes Baikal and 



Titicaca, 64. 

 Amphiiimn, external limbs in, 76. 

 Ampyciui, 134. 



Amp'yx, 113, 130, 138, 220, 221. 

 eye-spots lost in, 135. 

 fourth annulation in, 127. 

 free-cheeks iu, 135. 

 structure of sutures in, Angelin, 

 1.34. 

 Anacheirurus, 155. 



pentamerous lobation of glabella 

 in, 155. 



anagerontic stage, 248. 

 Anastrophia, 387. 



absence of embryonal sinus in, 388. 

 inter nascens, 315. 



discussion of, 337. 

 valves in, 388. 

 Ancistocrauia, 244. 

 Ancylobrachia, 290, 411, 412, 417. 

 ceutronelliform loop in, 411. 

 classification of, 305. 

 loop in, 410. 

 Ancyluceras, 96. 

 Ancyropijge, 151, 152. 

 Aneucanlhus, 140. 

 animals, defence in, Moms, 52. 



and plants, limitations of the forms 



of species of, 7. 

 parasitic, reduction in limbs of, 83. 

 Annelida, 252. 

 annelids, moutli of, 255. 



Waldron, 313. 

 Angelin, N. P., structure of sutures in 



Ampi/x, 134. 

 Angelina, 142, 145. 

 Anomia, 399. 



acukata, prodissoconch of young, 

 20. 

 spines in, 51. 

 byssal plug of, 38. 

 discoid form of shell in, 287. 

 phylogeny of, 23. 

 smooth prodissoconch of, 18. 

 Anomocare, 142. 

 Anopolenus, 142. 



antelope of America, prong-horn, com- 

 pound antlers in, 68. 

 antenna;, anterior, in Triarthrus, 205. 



posterior, in Triarthrus, 206. 

 anteunules in Triarthrus, 205. 

 Anthrodesmus octocornis, spine growth 



from frustule of, 43. 

 antler, definition of, 9. 

 antlers, compound, in deer family, 68. 

 iu prong-horn antelope of 

 America, 68. 

 in both sexes of Procervulus, 57. 

 in deer and elk, 9. 

 of deer, 21. 

 of fallow deer, 53. 

 simple, in Tertiary deer, 52. 



of young deer and elk, Lydek- 

 ker, 24. 



