32 PROCEEDINGS OF THE ACADEMY OF [Jan., 



to the narrow-banded conditions; ventrally from the two-lined form 

 to one .with a single row of spots anteriorly. The longitudinal 

 stripes on the neck and the oblique body stripes typical of N. c. 

 compressicauda are well defined on two specimens before us from 

 St. Petersburg. There is another specimen from the same region 

 which approaches N. c. loalkeri in characteristic ground tone and 

 markings, but the dorsal surface is darker and there is a vestige of 

 the neck stripes found in A'', c. compressicauda and N. c. tceniata. 

 One Key West specimen follows the description of A'', c. compsolcema 

 almost exactly, while four others from Key West form distinct steps 

 toward the typical walkeri pattern and coloration. Eliminating 

 the three specimens from St. Petersburg, Tampa Bay, and the one 

 from Key West which have a uniform straw-color and leaving out 

 the one specimen from Key West that approaches N. c. ohscura and 

 which may be considered as melanistic, we have ten specimens 

 remaining which seem to show a gradual change in pattern and color 

 from N. c. compressicauda, through N. c. tceniata, N. c. compsolcema, 

 to N. c. walkeri. Throughout this series no one character is dis- 

 tinctive enough to separate a race, although the Key West specimens 

 all show a darker ventral surface. The straw-colored form is uniform 

 and therefore has no distinguishing color characters, but the sooty 

 variety approaching N. c. ohscura seems to be a melanistic form of 

 N. c. compsolcema, since its spots and faint bars have that arrangement. 

 The scale rows of the adult specimens present as pronounced a 

 variation: there is no correlation between the color patterns and 

 the number of scales and the counts given by Cope cannot be taken 

 as differential characters of separate races. Two of the specimens 

 before us have twenty-three dorsal rows, yet one has a color pattern 

 typical of N. c. compressicauda while the other approaches N. c. 

 walkeri. The range of the scale counts of the Tampa Bay specimens 



is expressed by the formula: 



„„126-135 



"^^ ^^ 68-83 ' 

 and the average is : 



The Key West specimens, on the other hand, have the range of 



128-134 



72-82 

 and the average of 



13L2 



77.7 



