PARTULINA, SECTION BALDWINIA. 103 



for instance, is a pretty sure sign that the trees are no longer 

 in a healthy condition. 



" With a view to determining the nature of the food of 

 A. confusa, the writer with the assistance of Dr. Nicholas 

 Russel, examined microscopically the feces of a number of 

 individuals. In only two instances were minute particles of 

 chlorophyl found and these, perhaps, were accidental. The 

 great mass of the remains appeared to be of minute fungi or 

 algae. 



' ' To what extent the fungus-eating habit prevails through- 

 out the Achatinellidce remains to be determined by future 

 observations, but from the fact that many other species are 

 known to reside upon dead trees, or upon the dead branches 

 of living trees, it may be presumed to be somewhat general if, 

 indeed, fungi be not the main reliance of the family. In con- 

 nection with the food of the Achatinellas, it is of interest to 

 note that in a number of instances small but apparently thriv- 

 ing colonies were found on dead stubs which had not borne a 

 green leaf for years, perhaps twenty or more. It would seem 

 that under such circumstances fungi must be the sole depend- 

 ence of the shells. As such stubs are often within a few yards 

 of living trees of the same species, there would at first sight 

 appear to be no reason why the colonies did not abandon the 

 trees after they died and make their way to other trees. Ap- 

 parently, however, the mollusks either do not care to migrate 

 even a short distance, or are incapable of doing so. - In any 

 event, their isolation, whether voluntary or involuntary, is 

 complete, and successive generations of mollusks live and die 

 on the same tree where they were born, even after the latter 

 perishes and until it finally crumbles away. 



" The ability of the Achatinellas to maintain life for con- 

 siderable periods without food, and to found colonies and 

 live indefinitely upon dead trees, greatly favors their chances 

 in the struggle for existence. 



' Many experiments have been tried from time to time in 

 transplanting the Achatinellas from one locality to another 

 and even from island to island, but in no instance known to 

 the author have they been successful. The writer experi- 



