PARTULINA, SECTION BALDWINIA. 97 



Plains, which for its extent and peculiar character deserves 

 more than passing notice. 



The P. confusa lives chiefly upon the pua tree (Olea 

 sandwichensis) although in some localities it has been found 

 abundant upon the ilima (Sida sp.), a low shrub with yellow 

 flowers. It occurs also upon the mamani (Sophora chryso- 

 phylla) . Whether from the fact that the pua is not common 

 over the island of Hawaii, or for some other reason, I did not 

 find this shell, which is far more abundant than either of the 

 other species, outside of the above region (Mr. D. Thaanum 

 has found it widely spread in the Waimea plains) . 



The colony in question occupies perhaps 150 pua trees, 

 which cover an area of perhaps half a mile square, many 

 trees being more or less widely separated from their fellows, 

 The pua is a small tree fifteen or twenty feet high and with a 

 small spread of branches. A rough estimate of the number 

 of adult shells inhabiting this area when first visited is more 

 than 75,000 shells, and it was possible to ride under the trees 

 and from their trunks, leaves, and branches to pick shells 

 literally by the handfuls. Cavities in the trunks and branches 

 were usually packed with shells, mostly immature, from 50 to 

 75 being often found together. Wherever there were logs, 

 dead branches or large rocks under the trees, they, too, har- 

 bored large colonies of shells, and the presence of young in 

 numbers showed that these places were their permanent 

 abode. 



' ' In six hours, without climbing a tree, the author had no 

 difficulty in gathering 1,100 adult shells, and his companion, 

 Mr. William Horner, did the like a statement which will suf- 

 ficiently attest the abundance of the mollusks. The locality 

 becoming known to several shell collectors, something like 

 10,000 adult shells were gathered in the course of threes 

 months without seriously diminishing the numerical strength 

 of the colony. It is doubtful if so many tree shells of any 

 one species were ever found in a like area, even in the Ha- 

 waiian islands, abundant as the Achatinellas are, or used to 

 be, in some places. 



" The colony in question comprised numerous color varie- 



