Species o/Amphidromus, Albers. 67 



My thanks arc due to Prof. A. Lang (for permission to 

 view Mousson's types), Prof. Dr. E. von Martens, Dr. Aug. 

 Brot, and M. Jules Mabille (for kind assistance while 

 examining specimens at their respective museums). I am also 

 indebted to Mr. S. Hansen, of Copenhagen, for comparing 

 specimens with Miiller's types, and to Dr. Jousseaurae for 

 notes on A. Perneri and A. hemicyclas of Rochebrune. 

 Lastly, I am especially inlebted to Mr. Edgar A. Smith, of 

 the British Museum, without whose kind assistance in giving 

 me free access to books and specimens I could not have 

 compiled this list. 



Growp of K. perversus. 



1. A. perversuft, Linn^, Syst. Nat. 10th ed. ; Fer. Hist, 

 pi. cxlviii. figs. 1-8 ; Homb. et Jacq. Voy. au Pole 

 Sud, pi. viii. fig. 9. 



=citrimis, Brug., Chem. ed. ii. pi. ix. figs. 1, 2. 



=obesus, Martens, Ost-Asien, p. 351 ; Chem. ix. figs. 93-4, 935. 



Loc. ? 



The type has been lost, but the uniformly yellow-coloured 

 specimens, figured as above mentioned, are accepted as agreeing 

 best with Linn^'s description. Martens's ohesus is a small 

 form, generally somewhat broader in proportion to its length 

 than typical perversus^ but agreeing perfectly with it in 

 other respects. 



A. perversus^ var. tenera^ Martens, Ost-Asien, p. 350. 



A very thin shell, of the form of typical perve7^sus and of a 

 pale yellow colour. 



A. perversus, var. cJdoris, Beeve, Con. Icon. 1848, Bui. 

 fig. 223. 



Loc. Malay Peninsula. 



Tyjncal specimens are of a narrower form than pe7'versus, 

 and have a narroio white hand heloio and encircHng the suture ; 

 except for the last-mentioned character there is hardly any 

 difference sufficient to separate this from typical perversus — - 

 that is, when one has a series of specimens under examination. 



A. perversus, var. entohapta, Dohrn, Nach. d. deut. Gesell. 

 1889, p. 21. 



Loc. Paragua Island. 



The greater size of aperture in proportion to the length of 

 shell and a rather coarse oblique striation separate this variety 



5* 



