272 FAUNA HAWAIIENSIS 



The Limacidae yield nothing very peculiar or very striking and the few forms 

 peculiar to the Islands may well have been developed from introduced European 

 ancestors. 



The Zonitidae are scattered over the Islands ; all are peculiar, but they are 

 nearly related to forms found in other islands of the Pacific : similar remarks apply 

 to the Endodontidae, one group of which [Pterodiscits), however, appears to be peculiar. 



The presence — and that strongly contested — of only a single indigenous species 

 of the Helicidae again indicates affinities with Polynesia. 



The Pupidae as a family, have a very wide geographical range, and hence no 

 deductions can be drawn from their presence ; it should be noted that here — if the 

 identification be correct — the fauna includes a species not peculiar to the Islands. 



With reference to the Achatinellidae it may at once be noted that several divisions 

 of the family may be made. First, the brightly coloured forms which fall into the 

 genus Achatinella proper and which are replaced in the Southern Pacific Islands by 

 the genus Partula. The metropolis of distribution of all these forms seems to be 

 Oahu, save in the case of the subgenus Partulina when Maui and Molokai appear to 

 divide the honour. No species has been found on Kauai and only two on Hawaii at 

 the other end of the group. Species have been described by authors upon coloration 

 and band-formations ; in my opinion numbers even of the ' species ' here admitted will 

 prove, when their anatomy is carefully investigated, to be varying forms of one common 

 species. Consider, for example, such a shell as Tacliea nemoralis dealt with in the 

 same manner as the Hawaiian forms have been ! Still, even when reductions are made, 

 the fauna will remain remarkable for its numerical strength in species. 



Secondly, passing through Perdicella and Newcombia, confined to the islands of 

 Molokai and Maui, we come to the second great division, typified by Leptachatina and 

 Amasti'a. Here, while the metropolis again seems to be Oahu, Kauai, the oldest 

 island geologically considered, ranks well with the rest. 



Thirdly, passing through the interesting and recently described Thaammiia of 

 Oahu, we come to Carelia, which is confined to Kauai save for one subfossil species on 

 the Island of Niihau (the only mollusc on that island). 



Fourthly, we have the little group of Aufiadella and Frickella, which leave the 

 impression that they are linking forms between Achatinella and Tornatellina, and, 

 again, belong in the main to Oahu. It should be borne in mind, as illustrating the 

 peculiarity of the fauna, that only about half a dozen out of, approximately, 330 

 species of Achatinellidae are found on more than one island, and indeed some of 

 these may be due to errors of identification. In our present state of knowledge a 

 faunal list is largely influenced by the ' personal equation ' of the writer. 



From the residue of the fauna but little is to be learnt ; the development of 

 Succinea appears abnormal and further research will probably reduce the so-called 

 ' species ' of this group. 



