1890.] SPECIES OF THE SILUROID GENUS ARGES. 451 



A. lon(/ifllis, sabalo, taczanowskii, and peruanus inhabit the Andes 

 of Peru, A. prenadilla and v/liymperi the Andes of Ecuador. I had 

 originally confounded the two latter species, when Mr. Whymper 

 submitted to me his specimens for identificatiou some years since, 

 but a renewed examination has convinced me that there are at least 

 three kinds of " Preiladillas " in Ecuador, instead of one as believed 

 liy Putnam. 



Akges taczanowskii, sp. n. (Plate XLI. fig. 1.) 



Arqes sabalo, part., Steindachn. Sitzungsb. Ak. Wien, Ixxii. 1876, 

 p. 598. 



D. 1/6. A. 1/6. P. 1/11. V. 1/4. 



Head as broad as long, one fourth of the total length (without 

 caudal). Eyes very small, about one third the width of the inter- 

 ocular space, midway between the anterior nostril and the posterior 

 border of the head, much nearer the upper extremity of the gill-cleft 

 than to the posterior nostril ; nostrils much nearer the end of the 

 snout than to the eyes. Three rows of teeth in the praemaxillary, 

 mostly unicuspid, the outer row comprising about twenty teeth; 

 mandibular teeth of the outer row larger and deeply notched. 

 Labial lobes large and graulate all over ; the cleft of the mouth 

 measures one half the width of the buccal disk ; barbels measuring 

 half the length of the head. Adipose fin one third of the total 

 length (without caudal), very low and extending to the caudal. 

 The origin of the first dorsal is one third nearer the end of the snout 

 than the base of the caudal ; the first ray is somewhat prolonged 

 and its length equals the distance from the posterior nostril to the 

 posterior extremity of the head. Eirst pectoral ray prolonged, as 

 long as the head, extending as far as halfway between the head and 

 the anal, but not so far as the extremity of the ventrals. The latter 

 fins originate slightly in advance of the dorsal, and measure exactly 

 one half the distance between the base of their first ray (which is 

 much thickened but scarcely prolonged) and the anal. Anal opening 

 a little nearer the extremity of the ventrals than the origin of the 

 anal. Eirst anal ray three fourths the length of the ventral, half- 

 way between the extremity of the pectoral and the caudal. The 

 caudal fin is injured in the unique specimen examined. Yellowish, 

 above closely marbled with pale purplish brown. 



Total length (without caudal) 72 millim. ; length of head 18 ; 

 width of head 18; depth of body (above base of ventrals) 12. 



A single specimen, from Amable Maria, Peruvian Andes, is in the 

 British Museum. It was obtained by exchange from the Warsaw 

 Museum, in memory of whose regretted Curator the species is 

 named. 



AsGEs AVHTMPERi, sp. n. (Plate XLI. fig. 2.) 



D. 1/6. A. 1/6. P. 1/10. V. 1/4. 



Head as broad as long, 4| to 5 times in the total length (caudal 

 excluded). Eyes verj- small, about one fourth the width of the 



