112 THE NAUTILUS. 



Journ. Conch., I, 1865, p. 82) identified Ambloxis with Melantho 

 (of American authors). 



As Ambloxis has been recognized as ' ^Melantho ' ' by three 

 thoroughly competent authorities, Gill, Tryon and Binney, and 

 the latter author has figured a species to serve as its type, it 

 appears that we will be obliged to adopt Ambloxis as a generic 

 term to replace Melantho and Cavipeloma. 



Ambloxus Raf., Enum. and Account, etc., 1831, p. 3. Fol- 

 lowing the description of Melania rugosa Raf., and preceding 

 that of Melania viridis Raf. , Rafinesque wrote : 



"I leave the name of Melania to the shells with opening 

 obtuse at the end, or they may form the S. G. Ambloxus." 



In an earlier paper he had mentioned ' ' Melania Lam. ' ' In 

 the sentence quoted, he defined Melania and Ambloxus in one 

 and the same phrase, so that they are necessarily identical. 

 The type of Melania, M. amarula (L. ), becomes automatically 

 the type of the subgenus Ambloxus Raf., and it is here desig- 

 nated as such. 



Neither of the two species of "Melania" which Rafinesque 

 defined by diagnoses of less than two lines length, has been rec- 

 ognized. M. rugosa is probably one of several plicate species of 

 the region indicated by him, and it will never be possible to say 

 which, as his type-specimen is not known to exist, and no exact 

 locality was given for it. When a complete collection of the 

 shells of Licking River is available, it may be possible to guess 

 at the specific identity of M. viridis, which is described thus : 



" Suboval, smooth, five spires, end obtuse, opening oblong. 

 Fine shell, one inch, green, from Licking River." 



This is clearly a species of Campeloma (Melantho), a genus 

 which Rafinesque had named Ambloxis in 1818. From this, it 

 seems likely that Ambloxus was merely a lapsus mentis for 

 Ambloxis. 



In case it be ruled that Ambloxus is not equivalent to Melania 

 Lamarck, but must be restricted to one of Rafinesque' s species, 

 then the type will be Melania viridis Raf. ; and Ambloxus (1831) 

 will become a synonj^m of Ambloxis (1818). 



Melania virginica (Gmel. ), nominated as type of Ambloxus 

 by Mr. Hannibal, was not mentioned or implied by Rafinesque, 



