SOUTH AMERICAN NEMATOGNATHI. 25 



cessory barbel 011 anterior margin of its bony base. 

 Lower surface of the head with four irregular series of 

 cirri, the outer series continued backward to behind the 

 pectoral. 



Coracoid processes diverging backward, their length 

 about IJ-IJ in the distance between them at base. Hu- 

 meral process co-extensive with the coracoid process, the 

 pectoral pore almost immediately below its termination. 



Distance of dorsal fin from tip of snout about 4 in the 

 length; first dorsal ray greatly prolonged, filiform, some- 

 what longer than its distance from tip of snout. Outer 

 caudal rays slightly produced. 



Pectoral spine flattened, curved upward and back- 

 ward, its posterior margin with a series of spines which 

 are longer and stronger toward the tip, its anterior with 

 somewhat weaker teeth, its tip reaching beyond origin 

 of ventral fins. 



Dorsal surface chocolate colored, a series of squarish 

 darker spots on either side of the dorsal fold which are 

 more or less confluent; ventral surface plain, nearly 

 white; dorsal, pectoral, caudal and posterior portion of 

 anal dark brown; ventrals and anterior part of anal 

 light, the upper surface of ventrals dotted with dusky. 



Greatest width, before pectoral fins, about 7 in the 

 length; A. 57. 



Five specimens .20-. 22 in. Curuca, Rio Muria. Thayer 

 Expedition. 



FAMILY II. DIPLOMYSTID^E. 



= Diplomystidce Eigenm. Zoe, vol. i, 14, 

 This differs from the remaining families 

 dentiferous maxillaries. 



V. DlPLOMYSTES. 



Diplomyste Dumeril, "Ichthyol. Analyt., 487. 

 Diplomystes Bleeker, Nederl. Tijdschr. Dierkunde, i, 

 1863, 92 (papillosus). 



