PARTULINA, SECTION BALDWINIA. 95 



"It is probable enough, too, that in time the four color 

 sports, if indeed two of them are not already properly to be 

 ranked as species, will become completely isolated geographic- 

 ally when the present differences will be accented and per- 

 haps further differentiation occur. No doubt many of the 

 recognized species of the group have had origins and life his- 

 tories essentially similar to the forms here noticed. 



" How long these forms of horneri have been in reaching 

 their present degree of differentiation cannot, of course, be 

 told. Possibly they are nearly as old as the life of the species 

 on this island ; but in the case of creatures as plastic as the 

 Achatinellida appear to be, probably no very long interval, 

 nor very complete isolation, is requisite to establish such var- 

 iations. 



Partulina physa Newc. (hawaiiensis Baldwin). 



" This shell was described by Mr. Baldwin from the same 

 locality as the preceding, and its vertical range is about the 

 same. It lives chiefly upon the smooth-leaved variety of the 

 ohia but is found also of the kolea and casually on the haa 

 (Antidesma platyphyllum Mann). 



" Though this species varies much in coloration and size, 

 there cannot be said to be any constant and well-defined color 

 varieties, all the forms appearing to intergrade without limit. 

 As in the case of the previous species, however, every colony, 

 and sometimes the shells from individual trees within the 

 confines of a colony, possess peculiarities of their own slight 

 differences of color and size, often sufficient to the eye of a 

 trained collector to distinguish them from those of <cther 

 colonies. The tendency to differentiate is the same In kind, 

 but for some reason or other is has not progressed so far as 

 in the case of horneri ; possibly isolation has not been so com- 

 plete as in the other species, although observation does not 

 confirm this. 



' l The embryos of this species tend to follow the coloration 

 of the parent form to some extent, especially when the latter 

 are deep brown, but in most cases their colors do not indicate 

 their parentage with any certainty. 



