NO. I ACHATINELLA APEXFULVA DIXON — WELCH 207 



region IV has shells with unicolored embryonic whorls, and region 

 Ilia has embryonic whorls intermediate between the bicolored and 

 unicolored condition. In ridge complex i8, area 97A?? (fig. 8, p. 195) 

 has shells with white embryonic whorls; above this area (area 97) 

 shells with yellowish-brown embryonic whorls are found ; and in 

 areas 98 and 99 at a still higher elevation shells with lighter buff em- 

 bryonic whorls occur. 



6. The color pattern of the postembryonic whorls varies at different 

 elevations, and this variation is usually more marked than the hori- 

 zontal variation. Shells from areas having a high rainfall tend to be 

 white and to have banded patterns ; those occurring in dryer situations 

 (lower zone III, zone II, and I) tend to have darker patterns which 

 are banded and streaked. The region of maximum vertical variation 

 is region IV. 



7. Out of 20 ridge complexes, 13 show size increase with increase 

 of altitude between lower zone II and higher zone III. The remaining 

 ridge complexes are exceptions to the general trend. Although, the 

 correlation is not so clear-cut as for A. mustelina, a definite tendency 

 toward size increase with increase of moisture and lower temperature 

 exists in A. apexfulva, just the reverse of the correlation for A. 

 mustelinu. 



FORM AND COLOR 



8. The shape of the shell varies at random both vertically and 

 horizontally. 



9. No order in the distribution of dextral and sinistral shells is 

 ascertained. 



10. Color variation within a locality is often very extensive. This 

 makes it necessary to study large series in order to ascertain whether 

 a form is a distinct race or merely a color pattern of a known sub- 

 species. The same color pattern may occur again in a number of 

 widely separated localities. The embryonic whorls may be unicolored 

 or bicolored in the same locality. 



11. Form varies a great deal within a locality. A subspecies may 

 have narrow or obese shells. The spire may be straight, concave, 

 or convex in outline. Therefore, form is no criterion for the naming 

 of a species or subspecies until*the range of variations of a series 

 of specimens is studied. 



12. Over a period of years no size variation was noted in shells 

 from a definite locality. However, little data was available on the 

 subject. 



14 



