98 Evermann and Kendall — Fish from Central Ecuador. 



\dduals which fall respectively into several of his main categories, 

 excepting that of a well developed adipose fin without trace of 

 spine. In other words, judging by the principal di\dsions alone, 

 we have A. clycopum, eigenmanni, prenadilla and Jissidens. 

 They do not agree, however, in some other points, which, if 

 given consideration, prevent us from identifying our specimens 

 with any of his species. There is no doubt of the specific 

 identity of our specimens. The differences are mostly due to 

 age, size and sex. The adipose fin, as we have shown before, is 

 of doubtful value, and of no vahie whatever in the species to 

 which we have just called attention. The development of the 

 spine may be of value in larger specimens ])ut in one of two 

 small specimens we have there is a long spine connected pos- 

 teriorly with the caudal peduncle and in the other there is in 

 addition to the spine a long, moderately developed adipose fin. 

 Most of the other spines are small, just visible, imbedded in the 

 skin and appearing only as tubercles or not at all apparent. 



In the males, as already remarked, the ventrals are inserted 

 farther forward than in the females ; therefore, comparison of 

 extent of pectorals with ventrals or ventnils with proximity to 

 vent is of no value. In fact, there is such a range of variation 

 in these characters, regarded by Regan as showing specific dif- 

 ferences, that there arises a serious distrust of the value of any 

 of them for that purpose. Regan had the advantage of material 

 representing more species and localities than we have, but in 

 view of the foregoing fact the suggestion offers itself that unless 

 there are other grounds for separation, the five alleged Peru^aan 

 species may be, if not all one, certainly not more than two 

 species at greatest. 



Regan's figures of the various species show more dissimilari- 

 ties than do his descriptions, Ijut even the figures, taken in 

 conjunction with the variations in our specimens, indicate that 

 homodon and guentheri are possibly the two sexes of the same 

 species. Among the Ecuador species, one of the Atlantic slope 

 forms, A. festse, is clearly a distinct species, as shown by the 

 elongate nasal barbel. 



There seems hardly ground for identifying Madame Ida 

 Pfeiffer's specimens as A. cyclopum and estalilishing a new 

 species on individuals that agree more closely with the original 

 description and plate than the others do. Arges whymperi and 



