61 



jaws, and some, at least, which have exaggerated the insinuating habit 

 to the extent of becoming parasites in the gills of other fishes. Also 

 there are the Vandelliinae, in which the lower jaws are weak, the rami 

 no longer meeting in the middle, the teeth largely reduced to a few 

 pointed ones in the middle of the upper jaw, with which they make 

 abrasions in the skins of other fishes and of an occasional bather, to 

 drink his blood. To this crowd of disreputables belong the aforemen- 

 tioned Candiru. Finally there are little odds and ends tied into the 

 Tridentinse, minute creatures, the smallest of which is but 17 mm. long, 

 and the largest but 27 mm. The most that we can say of them is 

 to express the wonder that any of them were caught at all. 



The Nematogenyinse have either lost or never got opercular spines. 

 Nematogenys is large enough to be noticed. It has received the common 

 name "Bagre", and reaches a length of over ten inches at least. 



The Pygidiinse flourish in the mountains from southern Panama to 

 southern Patagonia, and in southeastern Brazil, also in the cataracts of 

 Guiana. A few of them are found in the lowland, but their optimum is 

 only reached in high altitudes, and with Astroblepus, a representative of 

 another catfish type, they reach the highest altitudes attained by fishes 

 in South America. 



One of them, Eremophilus mutisii, is exceedingly abundant on the 

 Plains of Bogota, where its name, "El Capitan", expresses the estimation 

 in which this Pygidiid is held. It has the habit of worming its way 

 into the mud and into the banks of streams and lakes. "El Capitan" is 

 speckled like a lake trout, and it is all but confined to the elevated basin 

 in which Bogota is situated. In the mountain brooks of Colombia many 

 species of the genus Pygidium are found in abundance. I recall one 

 sultry day sitting in a cool, clear, shallow brook near Honda, Colombia, 

 leisurely raking my fingers through the sand and pebbles on the bottom. 

 Minute fishes darted out of the sand and into it and under small rocks. 

 I lined a dipnet with cheese-cloth and went for them, dipping up sand, 

 gravel and all. I soon had a good number, eighty-nine to be exact, of a 

 new species of the genus Pygidium. Mr. E. B. Williamson caught a 

 specimen of another species, which was making its way up the vertical 

 wall of a waterfall. The sixty-three members of the genus Pygidium 

 range from southern Panama to Chile, Guiana and Rio Grande do Sul. 

 Very few species are known from the lowlands, but every mountain 



