48 



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

 reference to these specimens, and to specimens of the jaws exhibited 

 for that purpose, an explanation of the differences which exist, in 

 adult individuals, in the teeth of the sexes respectively ; those of the 

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

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

 of the teeth, equally 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. 



