340 REPORT OF NATIONAL MUSEUM, 1893. 



The Pit Vipers — family ('rntfilido—Contmned. Page. 



Leydig's investigations of the "pit" 364 



Peonliar to the crotalidH 365 



Poison apparatus 3€r> 



Osteology 366 



Mnsi-les 367 



Fangs ; 36« 



Reserve I'angs 368 



Poison gland 36!l 



Poison duct 370 



Does the poison duct enter the fang f 370 



Niemann's account of it 370 



Wyman's account : 371 



Johnston's account 371 



Muscles acting on gland 372 



Hypodernii c syringe - 373 



Poisonous fluid 373 



The bite 373 



Oontroversy about the movements involved 374 



Action as described by Dr. Mitchell 375 



Headless snakes strike 379 



Prof. Brewer's adventure 380 



Catlin's adventure 380 



The rattle 380 



Description 381 



Intern ill structure 381 



(iarman on the develo))nient of the rattle 382 



Ratio of growth 384 



Sloughing 384 



Feoktistow's observations on the rattle 384 



Quelch on the same subject 385 



Number of joints in rattle 386 



Shape according to age 387 



Position when sounded 387 



Sound 388 



Feoktistow's investigation of number of vibrations 388 



Ott's experiment 388 



Purpose of the rattle 389 



Involution of the rattle 391 



Derivation of the rattlesnakes 392 



Power of " charming " 392 



Kalm's explanation 393 



Mitchell's opinion 394 



Brehm's experience 394 



Hypnotism suggested 395 



Alleged fetid smell 396 



Rattlesnake dens 396 



Hudson's explanation 397 



Breeding habits 398 



" Do the snakes swallow their young?" 398 



Mimicry of crotalid snakes 399 



Natural history of the )>it vipers of the United States 401 



Synopsis of the genera 401 



Genus Af/kistrodon 401 



Synojisis of species in the United States 401 



