POISONOUS SNAKES OF NORTH AMERICA. 349 



by another snake (Ophibolus doUaiits) which was kept in the same cage, thns iire- 

 venting me from finishing the observation. A few days after, the same Trimorpho- 

 (lon caiight another Citemidoiihorns by the left arm and chewed it several limes. At 

 the end of a few minntes the bitten animal died withont convnlsions, without 

 agitation, as if asleep, a little bloo<l issuing I'rom the wound. 



A little later (1885), Mr. Otto Ednmud Eiife* published some observa- 

 tions, also made in 18S2, on Tarhophis inrax, an opistoglypli snake 

 inhabiting the countries bordering on the Eastern Mediterranean, and 

 from his account we quote as follows: 



I offered the half grown snake a perfectly healthy Lacerta rivipara, which he at 

 once commenced to lap with his tongue and then grasped slowly behind the fore legs. 

 The lizard defended itself as best it could and used its teeth well on the enemy. In 

 less than a minute the lizard was almost motionless, the jaws were powerless, and 

 the eyes closed; before the expiration of another half minute the lizard died, and 

 was then swallowed. 



Prof. Leon Vaillant, of the Museum of Natural History, at Paris, 

 observed the poisonous effect of the bite of another of the opistoglyph 

 snakes, Tragops prasinusy Wagler, and gives the Ibllowing interesting 

 account of one of the observations :t 



A small living green lizard was presented to the snake by means of a forceps. The 

 enake seized it across the neck without descending from the shrubbery among which 

 it used to live, and by the play of the jaws drew it back to the corner of the mouth. 

 The lizard tossed and bent about, winding its body and tail round the head of the 

 snake; three minutes later it hangs down inert, only the tail still trembling; after a 

 similar space of time convulsions of the whole body occur again, twining itself 

 around the head, then relajtsing Avithout motion, except some spasmodic undulations 

 of the tail; this lasts for two minutes, and the animal is dead. It will be seen that 

 this poison must have been tolerably active, as it caused the death of the lizard in 

 about eight minutes after the puncture by the fangs, which must have taken place 

 when the lizard reached the angle of the mouth, as the snake made no movement 

 after that. 



It seems quite plain from these observations that we have here to 

 do with a specific poison. The victims succumbed within a very short 

 time, and while it is evident that death was not caused by the mechau- 

 ical injury inflicted by the bite, much less by the shock, there is as 

 little room for assuming that it was due to the action of bacteria- 

 infected ordinary saliva. 



These experiments have agaiu roused the interest in the morphology 

 and physiology of -these glands, and two years ago, sixty years after 

 Duveruoy's work, Mr. F. Niemann published f some investigations 

 upon this subject. Among other snakes he dissected and described 

 two species with posterior grooved fiings, and he clearly demonstrates 

 that, in both, the yellowish gland has already passed the innocuous 

 stage and become a true poisou gland, though structurally somewhat 

 intermediate — as are, in fact, the fangs. He found in both species the 

 yellowish gland well circumscribed and clearly differentiated from the 



* Zool. Garten, 1885, p. 45. 



tMem. Centen. Soc. Phibmi., 1888, Sc. Nat., p. 44*. 



tArchiv f. Naturgeschichte, Lviii, i, 1892, pp. 262-286, pi. xiv. 



