Cock, chapparal, 354. Cockroach, 192. Codfish, 284. Cœcilians, 302. Cœlenterata, 92; classification of, 96; development and life-history of, 95; form of, 93; skeleton of, 95; structure of, 94. _Colaptes auratus_, *355. _Colaptes cafer_, 355. Coleoptera, 206. _Colinus virginianus_, 350. Collections, making, 461. Color, use of, 424. Colors, warning, 430. Colubridæ, 319. _Columba fasciata_, 351. _Columba livia_, 351. Columbæ, 351. _Colymbus auritus_, 343. Comb-building of honey-bee, *221. Comb of East Indian honey-bee, *222. Commensalism, 155, 413. Communal life, 411. Condor, California, 352. _Condylura cristata_, 391. Conjugation, 35, 60. _Conotrachelus cratægi_, *212, 213. _Conotrachelus nenuphar_, *214. Constrictor, boa, 324. _Conurus carolinensis_, 353. Coot, American, 349. Copperhead, 322. Coral, 95; branching, *104; red, 106. Coral islands, 104, 106. Coral polyps, 104. Coral reefs, 106. Corals, 92, 102, 104. _Coregonus_, 283. _Corisa_, 197. _Corisa_ sp., *199. Cormorant, 346. Cornea of eye of horse-fly, *186. Cottontail, 390. Coyote, 398. Crab, 151, 152; soft-shelled, 154. Crabs, *153. Crane, sand-hill, 348; whooping, 348. Crayfish, dissection of, 18, *18, 22; life of, 146. Cricket, house, *193. Cricket, 192. Crinoid, *126. Crinoidea, 121, 125. Crocodile, 326. Crocodilea, 313, 325. _Crocodilus americanus_, 326. _Crotalus_, 322. Crustacea, 144, 146; form and structure of, 147. _Cryptobranchus_, 298. Ctenophora, 97, 107. Cuckoos, 354. _Cucumaria_, 124. Cucumber-beetles, 209. _Culex_ sp., 204, *205. Curculio plum, *214. Curculio quince, *212, 213. Curlew, long-billed, 350. Cuttlefishes, 255. _Cyclas_, 247. _Cyclophis æstivus_, 320. _Cyclops_, 148, *149. Cyclostomata, 278. Cytoplasm, 38. Dabchick, 343. _Dactylus_ sp., *249. Damp bug, *151. Darters, 282. _Dasyatis_, 281. Decapoda, 151. Decapods, 256. Deer, 396. Degeneration, 417. _Dendrostomium cronjhelmi_, *134. Development, defined, 3; embryonic, defined, 62; post-embryonic, defined, 62; simplest, 59. _Diapheromera femorata_, *427. _Diaspis rosæ_, *198. Dictynidæ, 235. _Didelphis virginiana_, 390. _Diemystylus torosus_, *299. _Diemystylus viridescens_, 297. Dimorphism, 96. Diptera, 201. Distribution, barriers to, 437; geographical,435; laws of, 436; local, of birds, 367; modes of, 437. Diver, great northern, 343. Dolphins, 393. _Doris tuberculata_, *254. _Draco_, 319. Dragon-flies, 294. Dragon-fly, *196. Dragon, flying, 318. Drawings, 447. _Dryobates pubescens_, 355. _Dryobates villosus_, 355. Duck, ruddy, 347. _Dyticus_ sp., 210. Dytiscidæ, 207. Eagle, bald, 352; golden, 352. Ear of locust, *187.