434 VARIATION AND ZOOGEOGRAPHY OF LIGUUS IN FLORIDA 



with Hyatt's idea of acceleration of these variations in phylogeny a do t ' 



in 



which palaeontology seems to support. The "law of biogenesis" involved 

 Hyatt's doctrines is much too large a subject for discussion here. 



The origin of races by suppression or absence of characters may be m d 

 plainer by a simple formula, in which letters stand for the characters thus* 



Presence of green lines, G, absence g. 

 Presence of rose coloring, R, absence r. 

 Presence of yellow coloring, F, absence y. 

 Presence of brown coloring, B, absence b. 

 Sutural and peripheral lines, dark, L, white I. 



The several forms would have formulas as follows : 



Liguus fasciatus lignumvitce, GRYBL, or GRyBL 

 Liguus fasciatus castaneozonatus , GR YBL y or gRyBL. 

 Liguus fasciatus roseatus , GRYbL, or GRybL. 



Liguus fasciatus testudineus, GR YBl y or gryBl. 

 Liguus crenatus. Grybl, or GrYbl. 



Two pairs of characters, yellow or white ground, and thick or thin columella, 

 run through nearly the whole Floridan series, probably as Mendelian alternatives, 

 and not consistently correlated with other features. Although they readily 

 lend themselves to biometric treatment I have not had time to consider them in 

 this paper. 



Fio. 1. L. crenatus segregate, from the hybrid colony of Key Largo, showing heavy and thin 



forms of columella. 



Variations in intensity or extent of a pattern among individuals 

 colony (as in PI. XXXIX, figs. 22a-22d) may be due to increase of potency in 

 a character inherited from both parents ; but this would not apply to differences 

 in intensity between separate colonies. Here we must recognize that progressive 

 or retrogressive changes in the potency of factors determining color or pa er 

 have taken place. In adjacent colonies, undoubtedly of common parentag , 





