IREDALE : LAND MOLLUSCA OF THE KEEMADEC ISLANDS. 373 



animals had somewhat different habits, as above noted. On account 

 of these differences I carefully preserved some animals for investigation, 

 and would refer to them as var. Moumoxikai, nov. var. By this means 

 it may be able to fix this variation. This shell is practically smooth. 

 The two described Norfolk Island forms which I would refer here, 

 insculptiim and imitatrix, are both heavily sculptured on the adult 

 whorls, but the initial ones are smooth. On Norfolk Island also 

 occurs a smooth race with a tendency to form sculpture, from which 



1 should deduce that the unsculptured form is the oldest. Not 

 much variation is shown in shape in the Kermadec shells, but the 

 Norfolk Island insculptiim seems to have a tremendous range, from 

 a flattened conical shape to a liigh turreted one, which latter has 

 become fixed in the species imitatrix. A still undescribed Norfolk 

 Island smooth form is somewhat flattened, resembling the Kermadec 

 species. 



Genus KiECONcnA, nov. gen. 



This generic name is pi'oposed for the shell called Helix Kermandeci, 

 Pfr. Mousson included it in the genus Microcystis in the Journ. de 

 Conch., vol. xxi, p. Ill, 1873. Hedley and Suter allowed it to 

 remain in the same genus in the Reference List of the New Zealand 

 Mollusca, but later Suter transferred it to Macrochlamys. 



The following notes regarding the generic name Microcystis may 

 be of interest. In the Index Moll. Beck introduced on p. 2 as a sub- 

 genus of Nanina, Gray, 



"Microcystis, Beck. 



1. M. pellicula, Beck. F.H. ix, A 5-7 (?). Antill (?). An 



H. Helicolimax fellicxda, F. (?). 



2. M. trifaciella, Beck. I. Jamaica. An H. trifasciata, Stentz (?). 



3. M. pictella, Beck. I. Jamaica. 



4. 3[. ornatella, Beck. I. Opara. 



5. M.Jtliceti, Beck. I. Pitcairn. 



6. M. amcenula, Beck. I. Opara." 



Sherborn gives a note to the following effect : " This appeared in 



2 pts. ; I, pp. 1-100, 1837; II, pp. 101-124, perhaps first in 1838. 

 This was a preliminary issue. The final issue of pp. 1-124 and 

 pp. 1-8 (the n.spp.) was issued in 1838." 



From this the above is absolutely the earliest introduction of 

 Microcystis, and unless the first species can be considered as equalling 

 "pellicula Ferussac " it must be regarded as a nomen nudum. The 

 pp. 1-8 (the n.spp.) mentioned bj^ Sherborn, which were issued in 

 1838, contain descriptions of the five succeeding species mentioned 

 after M. pellicula, and these are all described as '■'■Nanina {Microcystis) ", 

 and from this introduction it would appear that Microcystis must be 

 (juoted. The following is the order : — 



p. 2. Nanina {Microcystis) trifasciella, p. 2, No. 2. Hah., Insulam Cuba. 

 p. 3. ,, ,, pictella, p. 2, No. 3. ,, Ins. Jamaica. 



,, ,, ornatella,\).2,l^o. A. ,, Opara. 



,, ,, filiceti, p. 2, No. 5. ,, Pitcairn. 



,, ,, «OTa5?M<^fl', p. 2, No. 6. ,, Opara. 



