Irbdale. — Mollusca of the, Kermadecs and Norfolk Island. 505 



A species of Succinea lives on Norfolk Island ; this genus is absent from 

 the Kermadecs and New Zealand, though present in Australia and the 

 northern groups. 



The Polynesian genus Nesopupa is represented by a large sinistral 

 species with the mouth well armed, and quite unlike the Kermadec dextral 

 unarmed form I have called Pronesopupa. No relation of either form occurs 

 in New Zealand. 



The Polynesian Omphalotropis is well developed, three species and one 

 variety being admitted ; these species are closely allied to Fijian forms. 

 No member of this genus was found at the Kermadecs, though one species 

 lias been recorded from the extreme north of New Zealand ; but the record 

 is somewhat doubtful. 



The familv Diplommatinidae is also credited with three representatives, 

 all belonging to the genus Palaina. This is purely a Polynesian group ; a 

 solitary species appears on the New Zealand list, but will be almost certainly 

 omitted in the near future, and no member of the familv occurs at the 

 Kermadecs. 



Two subspecies only of Tornatdlina have been recognized, one of which 

 is confined to the Moohu Stone, a rocky islet off the north coast. The 

 peculiar item of note is that this species is not close to any of the five 

 distinct species I obtained at the Kermadecs, but recalls a Fijian species. 



A " Palvdestrina " concludes the list of living molluscs obtained on 

 Norfolk Island. I am unable to give any idea of its relations, save that 

 it differs obviously from the New Zealand Potamopyrgus, and no fresh- 

 water univalve was obtained at the Kermadecs. Of as great, or even greater, 

 interest were the shells collected as subfossil from the limestone quarry 

 at the south of the island, near Kingston. 



Associated with living forms such as Succinea norfolkensis Sykes, 

 Omphalotropis albocarinata Mousson, Quintalia stoddarti jloscula (Cox), 

 Fanvlum insculptum (Pfeiffer), Fanulum onitatrix (Sykes), Advena camp- 

 bdlii (Gray), Greenwoodoconcha castaneocincta (Sykes), were numerous shells 

 apparently now quite -extinct. The largest shells are the next in size to 

 Ail vena campbellii (Gray), and are of remarkable interest, as being, from 

 a very close criticism of shell characters, strictly referable to the Fijian 

 genus Fretum. Smaller shells are apparently typical Matheivsoconcha ; and 

 in this connection it is worthy of note that the living species of this genus 

 is, as far as is at present known, exceedingly rare. From sand contained 

 in these subfossils two minute species were sorted out — one a Johanneso- 

 concha, the other a Norfolcioconcha — both of which differ from the living 

 species. 



Still more peculiar is a large quantity of dead shells collected on Nepean 

 Island. This island is only three-quarters of a mile distant, and is apparently 

 devoid of vegetation. Three living species were obtained — two species of 

 Tornatellina, and the third Vallonia excentrica Sterki, an introduced European 

 form. This latter species has acclimatized itself on Norfolk Island, and by 

 some means has reached this inhabitable islet, and is now nourishing there. 

 The two species of Tornatdlina are interesting, as one of them is only sub- 

 specifically distinct from the Norfolk Island species, whilst the other is 

 quite different, yet has not been discovered on Norfolk Island. It does 

 not come near the Kermadec species. The dead shells are, however, of 

 an extraordinary nature ; the large bulk is composed of two species of 

 Belloconcha, differing appreciably from the main-island species. 



