Distribution of Sturgeons. 27 



and which forms a most natural link with the family of Goniodonts, 

 all the species of which are confined exclusively to the fresh waters of 

 Central and South America. The closeness of this connection will 

 be at once perceived by attempting to compare the species of true 

 Sonicari(B with the Scaphirhynhus. I know very well, that the 

 affinities of Goniodonts and Siluroids with sturgeons are denied, but 

 I still strongly insist upon their close relationship, which I hope to 

 establish satisfactorily in a special paper, as I continued to insist 

 upon the relation between sturgeons and gar-pikes, at one time posi- 

 tively contradicted and even ridiculed. I trust then to be able to 

 shew, that the remarkable form of the brains of Siluridce comes 

 nearer to that of sturgeons and Lepidostei than to that of any other 

 family of fishes. This being the case, it is obvious that there must 

 be in the physical condition of the continent of America some in- 

 ducement not yet understood, for adaptations so special and so dif- 

 ferent from what we observe in the Old World. Indeed, such 

 analogies between the organized beings almost from one pole to 

 another, occur from man down to the plants in America only, among 

 its native products ; while, in the Old World, plants as well as ani- 

 mals have more circumscribed homes, and more closely characterized 

 features, in the various continents, at different latitudes. 



As for the species of sturgeons which occur in the Canadian lakes, 

 I know only three from personal examination, one of which was 

 obtained in Lake Superior, at Michipicotin, another at the Pic, and 

 the third at the Sault ; though I know that they occur in all other 

 Canadian lakes, yet it remains to be ascertained how the species said 

 to be so common in Lake Huron, compared with those of Lake 

 Superior, and with those in the other great lakes and the St Law- 

 rence itself. As for the Atlantic species, ascending the rivers of the 

 United States west and south of Cape Cod, I know them to differ 

 from those of the lakes, at least from those which I possess from 

 Lake Superior. The number of species of this interesting family 

 which occur in the United States is, at all events, far greater than 

 would bo supposed from an examination of the published records. 

 Upon close comparison of thes pecimens in my collection from differ- 

 ent parts of the country, and in different museums, as those of the 

 Natural History Society of Boston, of Salem, of the Lyceum of New 

 York, my assistant, Mr Charles Giran, and myself, have discovered 

 several species not described. For this comparison I was the better 

 prepared, as I had an opportunity in former years of studying almost 

 all the European species in a fresh condition, during a prolonged visit 

 in Vienna. 



II. — Fishes of Lake Superior compared with those of the other 

 great Canadian Lakes. 



Besides the interest there is everywhere in studying the living 



