tANNALS N. Y. Acad. Sci., Vol. XXII, pp. 327-333. 20 December, 1912] 



NOTES ON THE HABITS OF A CLIMBING CATFISH (ARGES 



MARMOBATUS) FEOM THE BEPUBLIC 



OF COLOMBIA 



By B. D. 0. Johnson 



(Read in abstract before the Academy 13 May, 1912) 



Introductory remarks, offered by Bashford Dean at the meeting. — The 

 group of catfishes (Siluroids) holds a puzzling place among fishes. That it 

 represents one of the ancient groups of bony fishes, there can be no doubt, but 

 whether Siluroids are descended from some special line of ganoids or whether 

 they have been derived through a long series of specializations from some 

 ancestor essentially carp-like remains ever an open question. The trend of 

 later work, certainly, tends to ally them more closely with plectospondylous 

 forms, but many of their most important structural characters have never 

 been explained on such a basis. 



Thus, the limb-girdles of some of the catfishes, with their accompanying 

 muscles, have appeared to be primitive, and there has, as far as I am aware, 

 been adduced no evidence to show that these structures were derived from 

 highly specialized conditions of such living plectospondyls, for example, as 

 characinids. The habits of Siluroids, which would help to explain the signifi- 

 cance of these abdominal structures, have not been known to be remarkable, 

 and there is no suggestion, therefore, that the characters in question might 

 but be interpreted as highly modified rather than primitive. Accordingly, the 

 present paper of Mr. R. D. O. Johnson merits, I believe, the attention of the 

 Academy, for he shows that under conditions of stress, the ventral structures 

 of the catfish Arges have an especial value to the fish in enabling it to creep 

 against the strongest currents and to climb with great rapidity and skill. The 

 conclusion, therefore, is evident that we may now reasonably interpret the 

 puzzling fin-structure of Siluroids as developed in relatively recent times, and 

 as having little significance in terms of more ancient groups. 



Mr. Johnson, it may be mentioned, spent several years in the highlands of 

 the Republic of Colombia, and although the region he studied has been visited 

 by but few naturalists, it is nevertheless hardly to the credit of our "cloth" 

 that these observations on fishes should first be made by a mining engineer. 



The creeks and rivers of the Andes Mountains in the Kepublic of 

 Colombia, South America, are torrential in character. The great major- 

 ity of them are but a succession of falls, cascades, pot-holes and short 

 "riffles." The rainfall in the mountains is heavy and the rock under- 

 lying the stream beds is schistose in character and comparatively soft. 

 The rate of erosion is exceedingly rapid, yet the grade lines of these 



(327) 



