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Every effort has been made to get a sight of the type. 

 Mr. E. H. Matthews writes me, February 28, 1918, that he 

 sent all his own and the late Mr. Bednall's types to Mr. Tom 

 Iredale in London. The larger parcel reached London safely; 

 the smaller one, which may have contained the type of this 

 species under review, went down. 



Mr. Matthews was good enough to send me some nice 

 specimens that he refers to Bednall's pilsbryanus. These are 

 the same species I am describing herein as S. posidonialis, and 

 differ materially from Bednall's description in that the anterior 

 valve is concave and not convex, as stated by Bednall, and the 

 posterior valve is very flat and not strongly elevated and 

 arched, as shown in Bednall's drawing, also the mucro is 

 differently placed. 



On the other hand, the figure of the posterior valve in 

 Mr. Bednall's paper well illustrates the same valve herein 

 described and figured under the name of S. cymodocealis, and 

 his statement that the anterior valve is convex also corresponds, 

 but the figure marked (1) in Mr. Bednall's description does 

 not show the distinctive tapering characteristics in that species, 

 and his statement that the "raised character of the lateral 

 area does not extend to the outer anterior angle of tegmentum" 

 does not correspond. 



We are, therefore, with the material available, quite 

 unable to determine which, if either, of these very distinct 

 species was described by Mr. Bednall. Part of the description 

 appears to refer to one and the balance to the other. 

 Personally, in spite of the fact that Mr. Matthews, in common 

 with all other South Australian collectors, has in the past 

 referred the species hereunder described under the name of 

 S. posidonialis , to Mr. Bednall's shell, and it is well known in 

 all Australian collections of Polyplacophora under that name, 

 I am strongly inclined to think that the other species herein 

 described as S. cymodocealis , or one nearly allied to it, is the 

 species described by Bednall. Unless the type is still in exist- 

 ence it will be impossible to satisfactorily determine this ques- 

 tion, so for the time being we shall have to add the two species 

 herein described to our list of Stenochitons. Iredale and May, 

 in their paper on "Mis-named Tasmanian Chitons" (Mai. Soc. 

 vol. xii., pts. ii. and iii., p. 105, Nov., 1916), think they 

 recognize in Blainville's Chiton longicymba (1825) from King 

 Island a member, though not yet identified, of the genus 

 Stenochiton. I cannot concur with this opinion, and think that 

 Blainville's shell was more likely either Ischnochiton virgatus, 

 Reeve, or a near ally. The blue spots he speaks of are very 

 marked in that species, and the shell is comparatively smooth. 



