]9l>51 Michael: Sa(jifta ealiforuicn from Sa)i Diryo Rrgion 103 



Width of Body. — The body varies in width from 3.75 to 

 somewhat over 6.25 per cent of the length. Separating the 100 

 speeimen.s measured into six groups, each of which has a variation 

 in width of 0.5 per cent, and then splitting each of these groups 

 into seven sub-groups with reference to differences in length of 

 animal, the following correlation table may be constructed which 

 shows that the width-per cent is greatest in the larger animals. 



TABLE 2 



CORREL.ITIOX BETWEEN WiDTII-PER CeNT AND LENf!TH OP ANIMAL 



Examination of the numbers in brackets shows further that the 

 width-per cent is least in the smaller animals, for in 43 per cent 

 of those varying between 18 and 20 mm. in length the width- 

 per cent is 4.25-4.75, while the same width-per cent occurs in 

 only 22 per cent of those between 20 and 22 mm. in length, in 

 7 per cent of those between 22 and 24 mm., and in only 4 per 

 cent of those between 24 and 26 mm. Furthermore, while the 

 majority of animals whose lengths vary lietween 22 and 26 mm. 

 have a width-per cent of 5.25-5.75, a larger proportion of those 

 between 22 and 24 mm. have a smaller width-per cent and a 

 larger proportion of those between 24 and 26 mm. have a greater 

 width-per cent. It is therefore obvious that specimens of S. 

 calif ornica increase in width more rapidly than in length. Hence 

 the following facts, extracted from table 4, are of specific 

 importance : 



