284 



DR. 11. GADOW ON EVOLUTION 



[Mar. 20, 



total of these and of many others produces that general something 

 which so often tells the experienced what kind of lizard he has 



Text-fiff. 65. 



Lepidosis of the collar and throat. 



A= C. immiitabilis, Sahna, Crnz 1^0. 1. Edge of collar formed by a complete 



row of granules. A nest or cluster of enlarged granules in the centre of 



the throat. 

 B=C mexicamis, var. balsas No. 8. Collar composed entirely of ver^^ large 



scales. 

 C = C. deppei from San Carlos. A few single granules intercalated between the 



large scales forming the edge of the collar. 

 D=C sexUneattis from North Carolina. 

 E = C'. deppei, Cocoyul No. 5. 

 F=C. communis austraUs, Cuicatlan, half -grown. Collar composed of very 



small scales and many granules. 



got hold of, before siibmitting it to his artificial keys, which in 

 really interesting cases often refuse to work. 



Supraoculars + Collar + Humerus + Forearm + Femur 

 + Pores + Coloration = Species, 

 is a kind of condensed equation, but the line has to be drawn 

 at its length, lest the equation becomes bewildering when comparing 

 the variations of many kinds with each other. Since each of 

 these characters may have at least two values (large or small in 

 numbers or in size as the case may be), the possible number of 



