INDEX TO VOL. XVIII. 



Acridites formosus, 359. 

 Acridium vayum, 269. 

 JEgmhtis vociferus, 164, 174. 

 .ffigiothus linaria, 156. 

 iEschnosoma, S. A. species of, 63. 

 Agassiz, Louis, portrait of, 188. 

 Agelaius gubemator, 158. 



phoeniceus, 158, 172. 

 Agriogomphus, American species of, 52. 

 Agrotis Chardinyi, 117. 



claviformis, 115. 



coniosa, 238. 



digna, 115. 



Fauna, 237. 



Htm, 238. 



mfracta, 115. 



manifesto, 116. 



oblaia, 116. 



Olivia, 238. 



orthnrjnnia, 239. 



perpaiita, 237. 



personata, 238. 



prwfixa, 117. 

 Allium tricoccum, 401. 

 Alteration of Rocks, 108. 

 Ameiva praesignis, 405. 

 Amelancliier botryapium, 413. 

 canadensis, 413. 

 oblongifolia, 413. 

 Amphipteryx, American species of, 29. 

 Anas boschas, 175. 

 Anax, American species of, 32, 38. 

 Ancistrogaster, 283, 300. 



carthritica, 253. 

 r/nlosa, 259. 

 Ancon Sheep, 356. 

 Anechura, 289, 301. 

 Anisolabis, 289, 302. 

 Anisopteryx pometaria, 201. 



vernata, 201. 

 Annual MEimxG, 1875, 1 ; 1876, 332. 



EEPOETB, 1, 14, 332, 347. 

 Anolis ftp., 204. 



Schiedii, 407. 

 Anser byperboreus, 175. 

 Anthoecia arcifera, 123. 

 Anthus ludovicianus, 170. 

 Apachys, 2S9, 305. 



Aphylla, American species of, 49, 53. 

 Apple, monstrosity in blossoms of, 354. 



Apterygida, 289. 

 Aquila canadensis, 163. 

 cbrysaetos, 174. 

 Arcbibuteo ferruginosns, 174. 



lagopus, 163. 

 Ardea herodias, 164, 175. 

 Argynnis Cybele, 188. 

 Asparagus, 359, 401. 

 Astur atricapillus, 163. 

 Athene cunicularia, 162. 

 Atherinichthys microlepidota, 202. 



Basiliscus mitratus, 406. 



Batrachus picifici, 202. 



Bexdike, Capt. Chas. List of Birds 

 at Camp Harney, Oregon, 153. 



Berea, O., rock movements at, 273. 



Bernicla canadensis, 165. 



Black-knot, 236. 



Bonasa Sabini, 164. 



Boxd, G. W. On the origin of the Do- 

 mestic Sheep, 356. 



Botany, formation of a Section of, 

 353. 

 Meetings of the Section of, 

 353, 354, 355, 359, 400, 401, 

 413. 



Botaurus lentiginosus, 165. 



Bothrops pictus, 205. 



Botryllus, locomotive power of, 369. 



Bouve, T. T. On the Origin of Por- 

 phyry, 113, 217, 236; Reminiscences 

 of the early days of the Society, 242. 



Brachylabis, 290. 



Brachyotus Cassini, 161. 

 palustris, 173. 



Brachyryton claelia, 205. 



Branta canadensis, 175. 



Brooks, Dr. W. K. Embryology of 

 Salpa, 193; affinity of the Mollusca 

 and Molluscoida, 225; on the Tuni- 

 cata and Botryllus, 360. 



Bryophila percara, 414. 



Bubo virginianus, 173. 



Buccinum undatum, diminutive form 

 of, 284. 



Bucephala albeola, 175. 



Bufo agua, 204, 410. 

 globulosus, 412. 



The names of genera and species described as new are italicized. 



(419) 



