126 ]'kocp:edings of the malacological society. 



C'HiETOPLEURA NOBLLIS, Pilsbrj. 



lu the Man. Couch., vol. xiv, p. 30, 1892, Pilsbry included a species 

 ChMopleura nohilis, citing it as of Reeve, basing it upon " Chiton 

 nobilis, Gray, Reeve, Conch. Icon., pi. xxi, fig. 139, May, 1847. Not 

 Chiton twbilis, Gray; Chcetopleura nohilis, Rv., Cpr. MS." Reeve's 

 figure is reproduced on Pilsbry's pi. xiv, fig. 80. 



The species is included upon Carpenter's MS. notes which Pilsbry 

 quotes. Some extraordinary confusion lias here occurred, as part of 

 the note reads : " The above is written from the type specimen which 

 Rve. described as the C. nohilis of Gray, and which Mr. Adams 

 most kindly submitted to my examination." I have been unable to 

 fathom the connexion of Mr. Adams with the type-specimen, as 

 Reeve described his Ch. nohilis, Gray, from a specimen in the British 

 Museum, which is still preserved with the data upon the back of the 

 tablet. This shell is undoubtedly the New Zealand Eudoxuchiton 

 nohilis (Gray), so that we are confronted with the problem of Adams' 

 shell. As its whereabouts are unknown, it would seem necessary to 

 write off, as indeterminable, the species Ch. nohilis, Pilsbry. The 

 Reevean reference and figure pass correctly into the synonymy of the 

 New Zealand shell, whilst the citation of Pilsbry's name in connexion 

 with the missing Chcetopleura keeps the latter in perspective, so that 

 its rediscovery may be looked for. The unknown locality, of course, 

 handicaps the investigator. 



The genus-name Acanthochitona. 



In the London Medical Repository, vol. xv, 1821, John Edward Gray 

 published "A Natural Arrangement of Mollusca, according to their 

 internal structure". Dealing with the genus-name CA/ifo??, Pilsbry 

 (Man. Conch., vol. xiv, p. 150, 1893) quoted the matter dealing with 

 Chitons, but did not dispose of the questions offered by that excerpt. 

 Inasmuch as Pilsbry incorrectly quoted that extract, it is possible he 

 was indebted to second-hand information for his knowledge of the paper. 



If the concluding paragraph of Gray's article (p. 239) be studied, 

 the procedure is quite simple. This reads: "The genera that are 

 liere given mostly contain many sub-genera, and are what are called 

 by several modern naturalists natuial families ; but I prefer to call 

 them genera, and their subdivisions sub-genera, because then either 

 name can be used separately, and so suits both opinions, for the 

 genera may be made into families by changing the termination as 

 from limax to liraacidse, and because I think that it is easier to 

 recollect limax arion hortensis than arion hortensis alone, as genera 

 are now become so numerous that naturalists really want something 

 to let them know to what part of natural history they belong." 

 With this in front of us we know how to deal with the following 

 nomination on p. 234 — 



" Ord. 10. POLYPLACOPHOUA. 



(Description of animal, etc.) 



a. Plates placed on the back of the mantle. 



1. Gymnoplax or gymnoplacidte. Acanthochitona, Chiton fascicu- 

 laris, Lepidochitona, Chiton marginatus." 



