246 LUCINIDjE. 



If Lucina has been properly made the type of a sepa- 

 rate family, and is no longer to be regarded as a genus 

 containing many sections or subgenera, the validity of 

 the present genus can hardly be questioned. A com- 

 parison of the characters above given with those of 

 Lucina, as now sought to be restricted, will, I think, 

 suffice to convince most conchologists that Axinus is a 

 good genus. Those who are of opinion that the family 

 has no substantial or natural basis are of course at 

 liberty to adopt the old genus Lucina in its original in- 

 tegrity. I do not propose any new genus. Axinus has 

 already attained the respectable age of forty years. It 

 is at present in some danger of being set aside as obso- 

 lete or unfashionable ; but 



Multa renascentur quse jam cedidere, cadentque 

 Quse nunc sunt in honore vocabula, si volet usus, 

 Quern penes arbitrium est et jus et norma loquendi. 



These mollusks are of small size, and dwellers in mud 

 and sand at various depths of water. The species are 

 by no means numerous. Three of them are British and 

 European, and another is Cuban. Mr. Searles Wood 

 says, " Species strictly belonging to this genus have not 

 been described from any formation of an older date 

 than the tertiaries : the shell called Axinus obscurus, 

 from the Magnesian limestone, belongs to a different 

 group, and has already been made a genus of by Pro- 

 fessor King, under the name of Schizodus." The shell 

 of Axinus has no tooth. What has been taken for such 

 is merely the point of the hinge-plate, near the beak, 

 which becomes thickened, and even projects a little, in 

 full-grown specimens. This process is unlike the tooth 

 of any bivalve. The connexion of the valves depends 

 wholly on the ligament, and is therefore slight. Sowerby, 

 in proposing the present genus, instanced A. angulatus 



