IKEDALE : THE CHITONS OF THE KEEMADEC ISLANDS. 



47 



This species is named after Mr. W. R. B. Oliver, one of the 

 members of the expedition, who collected most of the living specimens 

 on Meyer Island. 



Remarks. — This species is closely I'elated to Onithochiton filholi, 

 Rochebrutie (= undalatus, auet.), from which it is at sight separable 

 by the girdle characters. Every specimen found was perfectly 

 smooth, and showed no approach to the ribbing which caused the 

 ' semisculptus ' confusion in the case of the Neozelanic species. 



The types, which have been figured, are to be deposited in the 

 Canterbury Museum, Chi'istchurch. The figures here given show 

 these shells which have not been dissected; I am having detail 

 figures prepared which will be published later in conjunction with 

 others covering the comparative questions raised. 



2. Comparative Review. 



My remarks in the Proc. Malac. Soc, vol. ix, p. 160, 1910, read : 

 "The noticeable features [of the Neozelanic Chiton fauna] are 

 the poverty of species of Ischnochiton , the large size of the 

 Acanthochites, the distinct nature of the Plaxiphora and Onithochiton, 

 and the presence of the genus Eudoxochiton. The Chitons collected 

 at Sunday Island agree in the majority of these items, yet possess so 

 manv peculiarities that they deserve some little notice." When 

 making this statement I had been contrasting the Chiton faunas of 

 the marine biological divisions of Australia, and I afterwards noted 

 the nature of the Lord Howe and Norfolk Island Chitons from my 

 examination of my friend Mr. Hull's collection. These have now 

 been fully reported upon, and 1 propose to make comparisons with 

 those, and show their essential distinction, though some apparent 

 close relationship is at first noted. A tabulation of the species 

 recorded from each group will aid in following my remarks. 



Kermadecs. 



Parachitoji viestayera 

 LepidopJeurus subtropicalis 

 Eudoxochiton perplexus 

 Eudoxochiton imitator 

 Plaxiphora mixta 

 (Acanthochites sp.) 

 {Acantlwchites sp.) 

 {Cryptoconchus sp.) 

 Ischnochiton kermadecensis, 



var. exquisitus 

 Sypharochiton themeropis 

 Rhyssoplax exasperata 

 (Lucilina sp.) 

 Onithochiton oliveri 



Lord Howe Island. Norfolk Island. 



L. catenatus 



A. leuconotus 

 A. approximans 



Ch. (? S.)funereus 

 Ch. (R.) howensis 



L. norfolciensis 



A. apiwoximans 



I. intermedins 

 Ch. (? S.)funereus 

 Ch. [R.) corypheus 



O. discrepans — 



The merest glance will show that whereas from Lord Howe Island 

 six species are recorded, from Norfolk Island there are only five. 

 I make the Kermadec Chiton fauna to total nine species and one 

 variety, with evidence of four others. Further study will show that 

 in the nine species three additional genera are represented, whilst in 



