Poisonouj Snakes of ihe World 



THE FAMILIES OF SNAKES 



The kt\vs j;i\i'ii in ('hiijiliT \'I1 disl iiifj^uisli tlic 

 \;iii<)us kiiuls of poisonous land snakes from one 

 uiiotluM-; (Miai)tt>r VIII distinpuislics llio poison- 

 ous sen snaki's. Often, liowever, tliere are hasic 

 ([luvstions as to whellier of not a sinike Av poison- 

 ous, and to what family it i)elon<fs. Sonictinics 

 a family allocation will act as a doiihle ciiccjc on 

 a lentafivo identilication and also, occasionally, a 

 family desiiriiation will Ke all tlial is possililc l)i' 

 cause of the I'ondition of tlie snake. 



Tlu' i'lijlnwin:;- key has heen (U^sii;-ne(l losort oiil 

 many kinds of nonpoisonous snakes and snake- 

 liko animals hefore linally distinguishinji helweon 

 typical harndess snakes and poisonous ones liy the 

 only positive means of identification of a poison- 

 ous kind — the presence of fanjjs in the upper jaw. 



To identify an animal l>y use of this key, the 

 I'cader nuisl he^jin with the lirsl couplet (pair of 

 •statements), decide whicji ()n(^ liescriiic-, llm ani- 

 mal al hand, ami llirn prori'i'd lo llin cuuplel 

 indicated at liie end of the proper desci'ipt i\(i 

 phfase. This |)i()cedure is fr)llo\\(Ml with the ne.xt 

 couplet and so oti. Thus, :in :dlciiiat i\ c decision 

 is oll'ei'ed with each <'ouplcl until Ihe i'ea<ler 

 linally deleiinines the proper calefToiv for the 

 animal, 'i'lic an una I nnisl |K)SSess i/// (d' I he cha r- 

 acterislics mentioned in Ihe projjer line of coup- 

 lets- -not just the linal chaiaclerisi i<\ Theicfoi'e, 

 it is always necessary to start al the liciriinnn<x 

 of the key. 



The following key sliould always he used if 

 there is any (|uestion as to whether or iK)t Ihe 

 animal at hand is a i)oisonous snake: 



KEY TO THE FAAAILIES OF SNAKES 



1. A. Body elonojate, but legs or fins present on NOT A 



front and/oi- rear parts of body SNAKE 



B. Body elonjiate, no leps or fins 2 



2. A. Skin slim}-, with or without bony (fish- NOT A 



like) scales "_ SNAKE 



B. Skin dry, with thin horny scales 3 



3. A. Skin formed into distinct broad rinjis that NOT A 



extend around body SNAKE 



B. Skin formed into small overlapping or 

 juxtaposed scales (not in rings), at 

 least on back 4 



Eye with a movable lid NOT A SNAKE 



No movable lid 5 



Tail round in cross-section; not oar-shaped 7 



Tail compressed into an oar-like blade 6 



Head covered with small granular scales; 

 no large shields on crown; watersnakes 

 of Southeast Asia COLUBRIDAE 



B. Some crown shields present; see fig. fi; 



seasnakes, Chapter YIII -— HYDROPHIDxVE 



7. A. A row of enlarged, transverse scutes (ven- 



trals) down the belly 11 



B. Body scales uniform above and below 8 



cfi: 



30 



