340 REPORT OF NATIONAL MUSEUM, 1893. 



The Pit Vii^ers — family fVofa 7j(?fP—Contimied. Page. 



Leydig's in vestigatious of the ' ' pit " 364 



Peculiar to the crotalids 365 



Poison ap)>aratus 365 



Osteology 366 



Mnscles 367 



Fangs - 368 



Reserve fangs 368 



Poison gland 369 



Poison dnct 370 



Does the poison duct enter the fang? 370 



Niemann's account of it 370 



Wyman's account 371 



Johnston's account 371 



Muscles acting on gland 372 



Hyjioderniic syringe 373 



Poisonous Huid 373 



The bite 373 



Controversy 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 



Internal structure *38l 



Garmaii on the development of the rattle 382 



Ratio of growth 384 



Sloughing 384 



Feoktistow's ol)servations on the rattle 384 



Quelth 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 



Evolution of the rattle 391 



Deri vation of the rattlesnakes 392 



Power of " charming " 392 



Kalm's explanation 393 



Mitchell's opinion 394 



Brehm's experien ce 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 pit vipers of the United States 401 



Synopsis of the genera 401 



Genus Agkistrodon 401 



Synopsis of species in the United States 401 



