INDEX. 



Age, effect on vertical distribution, 391, 398, 



405, 423, 431. 

 Algae, in autumn, 311, 357. 

 and. Chydorus, 301, 350. 

 irregular appearance of, 317. 

 relation of numbers to Crustacea, 308, 353. 

 in spring, 308, 356. 

 in summer, 353. 

 at thermocline, 417. 

 in winter, 307 . 

 See Food. 

 Anabaena, 304, 346, 349, 353, 420, 425. 

 Aphanizomenon, 307, 310, 318, 353, 364, 420. 

 Apstein. 290, 304, 326, 331, 340, 347, 348, 350, 



352, 367, 372, 395, 404, 406. 

 As erionella, 318. 

 Autumn, algae in, 318, 357. 

 Crustacea in, 311, 317. 

 temperatures, 299, 324. 

 vertical distribution in, 386. 

 Bacteria, 338, 398. 

 Bibliography, 433. 

 Birge, 274, 375. 392, 394, 421. 

 Bosmina, 301, 304. 

 Ceratium, 304, 310, 318, 346, 355. 

 Ceriodaphnia, 422. 



Chemical condition of water, effect on ver- 

 tical distribution, 423. 

 Chroococcaceae, 304, 350. 

 Chydorus, annual distribution, 304, 348. 

 in autumn, 311. 

 dependent on algae, 312, 364. 

 maximum and minimum numbers, 350, 



448 

 relation to light, 425, to temperature, 364. 

 reproduction. 364. 

 in summer, 310. 

 at thermocline, 418, 424. 

 vertical distribution, 382, 389, 407, 448. 

 Cladocera, see the various genera. 

 Clathrocystis, 317, 346,353. 

 Clouds, effect on vertical distribution, 410, 



426. 

 Cochituate lake, 293. 

 Coefficient of net, 278. 

 Coelosphaerium, 353. 

 Collections, dates of, 438. 

 Competition, effect on numbers, 321, 365. 

 Computing, methods of, 275. 

 Conochilus, 411. 



Copepoda, see the various genera. 

 Corethra, 310, 410, 418. 

 Crustacea, in autumn, 311. 

 average number, 313. 

 dominant, 316, 365. 

 diurnal movement. 407. 

 horizontal distribution, 366. 

 order of development, 316. 

 maximum numbers, 302. 

 number per cubic meter, 318, 437. 

 periodic, disappearance of, 312 ; appear- 

 ance of, 311, 358 ; number of, 304. 

 in spring, 307. 

 in summer, 309. 

 in upper meter, 409. 

 variation of in different years, 315. 

 variation of numbers, 368, 370. 

 vertical distribution, 375, 438. 

 in winter, 305 



food of ; relation to light, etc See Food, 

 etc., also, Cyclops, and other genera, 

 and Tables of Appendix. 



Cyclas, 424. 



Cyclops andC. brevispinosus, annual distri- 

 bution 395. 



in autumn, 311, 331. 



date of development, 316. 



decline in summer, 329, 385 . 



disadvantage of in summer, 331, 385. 



eaten by Leptodora, 351. 



food of, 355, 430. 



horizontal variation, 368. 



maximum numbers, 309, 319, 329. 



number caught in single haul and series, 

 284. 



numbers, table of, 441. 



rate of sinking, 430. 



relation to total Crustacea, 331. 



relation to light, 425 ; to temperature, 330, 

 359. 



reproduction, 291, 306, 309, 313, 329. 



species of, 326. 



in spring, 308, 316, 329, 337, 381. 



in summer, 309, 317 . 



at thermocline, 418, 424. 



in upper meter, 408. 



variation in numbers, 368, 370. 



vertical distribution, 337, 379, 381, 393, 396, 

 407, 413, 416, 422, 441. 



in winter, 327 . 

 Cyclops fluviatilis, 332. 

 Cyclops Leuckartii, 310, 326. 330. 

 Cyclops oithonoides, 331. 

 Cyclops pulchellus, 326. 

 Daphnia hyalina, annual distribution, 335. 



in autumn, 311, 312, 317. 



diseases, 338. 



eaten by Leptodora, 351. 



food, 353. 



growth in winter, 307. 



length of life, 336. 



males, 338,340. 



maximum and minimum numbers, 319, 

 339 . 443, 373. 



number of eggs, 361. 



relations of competition, 365 ; to tempera- 

 ture, 337, 361 ; to light, 372, 425. 



reproduction, 310, 336, 337, 361. 



sinking, rate of, 430 . 



in spring, 308, 316, 337. 



in summer, 309, 339. 



swarms, 372. 



variation in numbers, 368, 369 



vertical distribution, 383, 385, 387, 393, 397, 

 407, 413, 416, 422, 426, 443. 



in winter, 305, 336. 

 D. Kahlbergiensis, 301, 346. 

 D. longiremis, 401, 422. 

 D. pulicaria, annual distribution, 340. 



in autumn, 313, 317. 



food of. 352. 



horizontal distribution, 371. 



limitation of numbers, 342, 385. 



maximum and minimum numbers, 319, 

 445. 



number of eggs, 362. 



reproduction, 342, 362. 



in spring, 316. 



vertical distribution, 379, 385, 388, 399, 413, 

 415, 421, 427, 445. 

 D. retrocurva, annual distribution, 345. 



in autumn, 312, 317. 



affected by competition, 366. 



maximum and minimum numbers, 445. 



