48 



beiiig, in every instance, comparatively smooth. He added also, by 

 reference to these specimens, and to specimens of thejawsexhibited 

 for that purpose, an explanation of the difFerences ■which exist, in 

 adult individuals, in the teeth of the sex.es respectively ; those of the 

 malė becoming exceedingly lengthened and pointed, while in the fe- 

 male they retain very nearly their original flattened surface : the form 

 of the teeth, eąually with the armature of the surface, constituting 

 in these fishes a secondary sexual character, although both the one 

 and the other have repeatedly, but erroneously, been considered as 

 adapted for the establishing of specific distinctions. 



