IREDALE : ON KERMADKC MOLLUSCA. 219 



SO very different, and I liave therefore taken the extreme course of 

 differentiating the Kermadec sliell, until tlie nniscle-inipressions of 

 C. nutalus are made known. This, moreover, appears to be necessary, 

 as mj' generic characters depend upon the animal and muscle- 

 impressions, and I could not accurately name, as type, a shell in 

 which they are not known to exist. Probably this is the shell 

 recorded by Melvill & iStanden (Journ. Conch., vol. viii, p. 414, 

 1897) from Lifu, as Williamia radiata, Pease, which they phiced in 

 the family Acmeeidfe ! ! 



This and tlie following genus are named in honour of my friend 

 Mr. Hoy Bell, whose aid in investigating the Kermadec Mollusca 

 I wish to commemorate. 



RoYELLA, n.gen. PI. IX, Figs. 1, 2. 



I propose this generic name for the shell described as Cerithium 

 clathratum by Sowerby in the Thes. Conch. ^ vol. ii, p. 883, pi. 185, 

 tig. 258, 1855, from tlie Island of Bohol, and whose name was changed 

 to C. sinon (Pig. 1) by Bayle in the Journ. de Conch., vol, xxviii, 

 p. 243, 1880. When recorded from Lifu by Melvill & Standen 

 (Journ. Conch., vol. viii, p. 116, 1895), it was transferred to 

 Cerithiopsis. When I noted its history as above in these Proceedings, 

 vol. ix, p. 320, I observed: "I don't know where to generically 

 locate this shell, but it is certainly neither a Cerithium nor a 

 Cerithiopsis. '" Further research has shown its distinctness from 

 previously described generic forms, so I have been compelled to 

 erect a genus for its reception. I might add I have seen other forms 

 which appear to be congeneric. (Pig- 2, species undescribed.) 



The shell is long, narrow, many-whorled, and tuberculate ; apex 

 long, sinusigeral, and pink, whilst the main shell is white ; aperture 

 circular, with a short distinct recurved canal. Operculum horny, 

 raultispiral ; nucleus central. 



The operculum of Cerithiopsis is said to be " paucispiral, somewhat 

 concave, with three or four whorls, rather translucent and smooth 

 outside" (Dall, Bull. Mus. Comp. Zool., vol. xviii, p. 252, 1889), 

 whilst that of Bittium agrees better with this, but the shell characters 

 at once separate Royella from Bittium. The shells usually assigned 

 to Cerithiopsis and Bittium are of diverse generic types, and may be 

 separated by means of the characters of their apices. I would 

 recognize Joculator, Hedley, as fully worthy of generic rank, not 

 accepting the conservative view taken by its author. 



Brookula, n.gen. 



In the Trans. New Zeal. Inst., vol. xl, p. 382. 1907 (1908), 

 I recorded as i-ecent a shell described from the Pliocene as Scalana 

 cortdmn by Button (op. cit., vol. xvii, p. 322, 1884 (1885)), and 

 concluded: "Having carefully compared specimens, there is no 

 doubt it is congeneric with Cyclostrema atigeh\ Ten. -Woods, and for 

 the present the best location is in the genus Ci/clostrema.^' 



Since then I have examined quite a number of species which are 

 congeneric ; some were described as Rissoa, others as Scala or 



