308 J. K. Thachet — Median and Paired Fins. 



think the correctness of this view fully demonstrated, still he thinks 

 there is a decided balance of probability in its favor. Therefore the 

 ulnar side of the arm now appears as the Stammreihe. In other 

 particulars Gegenbaur reaffirms his previous views. He proceeds to 

 devote considerable space to the discussion of the origin of the 

 archipterygium, and again proposes to assimilate the limb and limb- 

 girdles to the gill-arches with their rays. He supports this sugges- 

 tion with considerable argumentation. To this position the archip- 

 terygium theory leads him. 



I take this opportunity for expressing my sense of the great advan- 

 tages furnished by the U. S. Fish Commission for the study of marine 

 life on our coasts, and in particiilar by the biological laboratory at 

 Wood's Hole, established in connection with that Commission, and 

 also for acknowledging my personal indebtedness to Professor Baird, 

 through whose courtesy I have enjoyed these facilities for a number 

 of summers. 



