THE AMERICAN NATURALIST [Vol. XLVII 



third or fourth pair of anterior ribs, on the fifth and 

 sixth vertebrae, that first extends to the belly scutes, and 

 the scute reached is the eighth. This makes three or two 

 scutes more than vertebrae in the neck region, and there is 

 probably a slightly greater difference than this in some 

 specimens, as there is a difference in the extent to which 

 the gular scales encroach 

 upon the region occupied 

 by the first scutes. On 

 the other hand, it is to be 

 noted, as shown by the 

 skiagraph (Fig. 1), that 

 it is the ribs of the 

 fourth from the last ver- 

 tebra that connect with 

 the last scute in front of 

 the enlarged anal plate, 

 the antepenultimate pair 

 terminating distally op- 

 posite the anal plate 

 (which has thus been 

 considered a part of the 

 belly series), and the 

 two last pairs of ribs ex- 

 tending into the base of 

 the tail. Counting the 



Fig. 2." Variation in the number ot anal P^te, then there 



uSriT^h^ ™ d J^ y ^ cales in Be0kM would be, barring the 

 vertebra}, Vmnies ; _+-!.+_+, varia- discrepancy anteriorly, 



in 0n seutJ S %tmaie™ ale — — ' — ^variT- tw0 m0re Vertebrae 



tion in scutes, mai.-s : \r v . „„,,'„ ,»un than scutes, but as there 

 M e s. : °men^ are about two or three 



14(5,75 ?) ' scutes in excess of ver- 



tebrae anteriorly the two extra ribs reduce the discrep- 

 ancy to one or nothing in the specimens dissected. That 

 this is about the normal condition is shown by the 

 variations in the series studied, and it may be concluded 

 that when the differences are more or less than this 

 number the discrepancy is due to the addition or loss of a 

 belly scute or two under the chin. 

















































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