TONGUES OF MOLLUSCA. 77 



as follows : — 1st male^ central tooth six points ; 2nd male^ 

 central tooth five; 1st female^ central tooth seven; and 

 2nd female,, central tooth five points : so that I find a male 

 and a female with each only five points, and, on the 

 other hand, a female with seven points, and a male with 

 six. This shows, I think, that in Buccinum undatum there 

 is nothing definite as to sex in the number of points, but 

 that, in describing this ribbon, the points of the central 

 teeth must be stated to vary from five to seven in 

 number. 



In Fusus antiquus I find the toothlets on the central 

 teeth to be either three or four. 



I may remark, that the general character of the teeth 

 in these two genera is perfectly similar, with the exception 

 of the number of denticles just mentioned ; and I am able 

 to show a series of specimens, including the two, which 

 run regularly up from three to seven toothlets, thus bring- 

 ing them extremely near together as regards their lingual 

 dentition. 



You will be surprised, then, to find that both Gray and 

 Adams make Fusus and Buccinum to belong not only to 

 difierent genera, but even to distinct families. I wiU not 

 venture to say that this is incorrect, but I may remark 

 that the entire internal anatomy of the two agrees very 

 closely. 



I can speak, however, with greater confidence on another 

 point, namely, the manner in which these two animals 

 are distributed by the naturalists just mentioned, — Fusus y 

 or Chrysodomus, as it is now called, being placed in the 

 family Muricidae, and Buccinum being made the type of 

 another family, the Buccinid(B, in which Purpura is also 

 included. Now, taking Murex erinaceus as a type of the 

 Muricidce, its anatomical structure, as well as its lingual 

 ribbon, is totally difierent from Fusus, with which they 

 unite it j while, on the other hand, all the species of Pur- 



