432 Dr. R. Philippi un the River-Fishes of Chili. 



papillse; but the hinder part is quite smooth. The inferior 

 surface of the head is scarcely papillose, without any warts, and 

 consequently very different from the condition of this part in 

 both the preceding species. The membrane between the nos- 

 trils is considerably smaller than in A. villosus. The adipose is 

 comparatively small, and the ventral seems smaller than in the 

 other species; the tirst measures 20 niillim., while the total 

 length of the fish is IGi millim. Coloration above blackish 

 grey, gradually passing into the greyish white of the belly. 

 The number of the fin-rays is :— D. 1.7; A. 9; C. 20-22; 

 P. 1 . 9 ; V. 6. The palatine teeth are proportionally as large 

 and long as those of the maxillary, and form two strongly 

 diverging oval patches. 



From A. papillosus this species is distinguished by the smaller 

 number of the rays of the anal fin (which in that species are twelve), 

 and by the condition of the palatine teeth, which are not 

 smaller than the maxillary teeth, and not " mousses et comme 

 un pcu grenues.^^ 



I received this species a few days since from the waters of 

 Peine, in this province ; the fishermen call it Tollo, Shark — a 

 name which I suspect they apply to all the species of Arius, 



6. Arius micropterusj Ph. 



A specimen long preserved in spirits, and, after a superficial 

 examination, referred by me to A. papillosus, is, however, very 

 distinctly removed from it by the comparative smallness of the 

 adipose and ventral fins, and by the palatine teeth being much 

 larger than the maxillary teeth ; they form two slightly di- 

 verging oval patches. The adipose fin has a length of only 

 28 millim. and a height of 6 millim., for a total length of 214 

 millim.; the ventrals are only 19 millim. long (These fins are 

 of the same length in A. squalus, which measures only 16i 

 millim., and has the adipose only 20 millim. long and 8 millim. 

 high.) The number of fin-rays is, I find, as follows : — D. 1.8; 

 A. 9 ; C. 18-20 ; P. 1 . 9 ; V. 6. The fore part of the body is 

 strongly papillose ; the hinder part smooth. Coloration blackish 

 above; beneath whitish : the pectoral and ventral fins are whitish 

 at the commencement, blackish towards the tip. 



7. Arius synodoUj Ph. 



This species is rendered very distinct by the fact that the 

 palatine teeth do not form two separate oval patches, but a 

 single ti'ansverse trapezoid rounded off at the angles ; in other 

 points they nearly resemble the maxillary teeth. The form of 

 the body also is slenderer, the head being not quite one-fifth, 

 or scarcely more than one-sixth, of the length of the body, 

 while in the other species it is nearly one-fourth of the same. 



