Miscellaneous. 69 



hair-like tips characteristic of those of the Emu and Cassowary, and 

 still less whether the apical portion of the feather supported simple 

 barbs such as occupy that position in those birds. The only fact of 

 importance, indeed, that I can hope to make known by this paper is 

 that the Binornithes undoubtedly possessed a large accessory plume, 

 thus adding another proof of their relationship to the green-egged 

 Emus and Cassowaries existing in the Australian region, and of their 

 difference from the white-egged group of Struthiones represented 

 in Africa and South America. — Proc. Zool. Soc. March 14, 1865. 



On the Metamorphoses undergone by certain Fishes before acquiring 

 the Adult Form. By Professor Agassiz. 



I have lately observed in Fishes metamorphoses as considerable as 

 those known to take place in the Amphibia. Now that pisci- 

 culture is followed with so much success and on so large a scale, 

 it is surprising that this fact has not been long since observed ; but 

 this may perhaps be attributed to the circumstance that these 

 metamorphoses usually commence after the hatching of the young, 

 at a period when they die rapidly, if kept in captivity. At this age, 

 moreover, they are for the most part too small to be conveniently 

 studied in their natural element. Nevertheless this is the most im- 

 portant period of their growth, if we wish to study their natural 

 affinities. I intend shortly to show how certain small Fishes, at first 

 resembling Gadoids or Blennioids, pass gradually to the type of the 

 Labroids and Lophioids. I shall also be able to show how certain 

 embryos resembling the tadpoles of the Frog or Toad, gradually ac- 

 quire the form of Cyprinodonts, — ^how certain Apodal Fishes become 

 transformed into Jugular and Abdominal Fishes, and certain Mala- 

 copterygians into Acanthopterygians, and, lastly, how we may found 

 a natural classification of Fishes upon the correspondence existing 

 between their embryonic development and the complication of their 

 structure in the adult state. 



Quite recently I have discovered that the metamorphoses of certain 

 members of the Scomberoid family are perhaps still more unexpected 

 than any of those which I have previously observed. Every ichthyo- 

 logist knows the characters of the Dory (Zeusfaber), and the pecu- 

 harities which connect this fish with the family of the Scomberoids. 

 Another less-known but very curious fish, Argyropelecus hemigymnus 

 (Cocco), which likewise inhabits the Mediterranean, has been gene- 

 rally referred to the Salmon family, or placed with the Salmons as a 

 subfamily. Systematic authors have generally regarded the Scom- 

 beroids and the Salmons as very different fishes, the former being 

 referred to the Acanthopterygii and the latter to the Malacopterygii. 

 Nevertheless Argyropelecus hemigymnus is neither more nor less 

 than the young state of Zeus faber. 



I expect that all ichthyologists will reject this assertion as erroneous. 

 Nevertheless nothing can be more true ; and therefore, instead of 

 seeking to prove it by long arguments, I shall, for the present, merely 

 request my confreres to procure small specimens of the Dory (of 8 

 to 10 centimetres in length), and to compare them with authentic 

 speeimens of Argyropelecus, feeling certain that they will admit the 



