ACHATINELLA DECORA. 333 



I do not know that tumefacta still exists. It was evidently 

 abundant when Gulick collected. There is also a good series 

 in coll. C. M. Cooke, taken by Mr. Emerson at about the same 

 time. PL 61, fig. 3 is decora from "Wahiawa," Cooke coll. 



A. decora has companions in A. valida Pfr., from further 

 west, and in A. mustelina of the Waianae range. The latter 

 was, in my opinion, derived from an old decora stock which 

 migrated southward. Some Waianae shells are hardly dis- 

 tinguishable from main range forms, but in general the muste- 

 lina variations are different. 



Ferussac in his first publication based Helix decora on the 

 figures in Chemnitz. He seems to have had another shell 

 which he described later (1824) in the Voyage of the Uranie. 

 This later decora was apparently the banded species subse- 

 quently called decora by Pfeiffer, Reeve and nearly all later 

 authors and collectors. It is the copiously banded form of 

 simulans well known from the western ridge of Nuuanu. 



The original decora is, as Gulick recognized in 1873, a short, 

 dark form of the shell better known as A. perversa. This form 

 was not uncommon in the old days, in colonies mainly com- 

 posed of longer, more variegated shells. Figures Ib, 2c of pi. 

 61 represents "Kawailoa" specimens of decora agreeing with 

 Chemnitz 's figures. Chemnitz gave the following description : 

 ' The shell is smooth as a mirror and brown-blackish colored. 

 Near the suture the whorls are very prettily encircled with a 

 white band. The apex is white. This rare sinistral snail, for 

 which Herr Spengler had to pay two guineas in London, lives 

 in fresh water of the Sandwich Islands in the South Sea. The 

 inner walls are whitish. As the inhabitants of these islands 

 are accustomed to wear this kind of snail as neck and ear 

 adornment, and therefore bore the shells in order to string 

 them, they made no exception of these rare sinistral snails, 

 which are likewise bored. ' 



The type of A. decora in the Spengler collection was prob- 

 ably brought to London by the expedition of Captain Dixon. 



The species was subsequently described as A. perversa and 

 well figured by Swainson, whose shells were from a lei brought 

 in England by Captain Byron. The shells on this lei 



