340 MEMOIRS OF THE CARNEGIE MUSEUM. 



accessory rays; distance from origin of dorsal to base of middle caudal rays 1.2-1.4 

 in the distance between snout and dorsal; distance from origin of dorsal to tip of 

 caudal sometimes less, sometimes greater, than its distance from the snout. 



A row of small spots along the middle of the sides, another along the middle 

 of the back and a third between the two. 



63. Pygidium punctatissimum (Castelnau). (Plate XLV, fig. 1.) 

 Trichomycterus punctatissimus Castelnau, • Anim. Nouv. Am. Sud., 1855, p. 49, 



pi. 24, fig. 3, GtJNTHER, Cat. Fishes Brit. Mus., V, 1864, p. 272; Ribeiro, 



Fauna Braziliense, Peixes, IV (A), 1912, p. 221. 

 Pygidium punctatissimum Eigenmann & Eigenmann, Proc. Cal. Acad. Sci. (2), 



II, 1889, p. 52; Occasional Papers Cal. Acad. Sci., I, 1890, p. 334; Proc. U. S. 



Nat. Mus., XIV, 1891, p. 36; Eigenmann, Reports Princeton Univ. Exped. 



Patagonia, III, 1910, p. 399. 



Habitat. — Rio Araguay. 



Known from the types, with the characters given in the Key. 



64. Pygidium minutum (Boulenger). 

 Trichoynycterus minutus Boulenger, Proc. Zool. Soc. Lond., 1891, p. 235, pi. 



XXVI, fig. 3. 

 Pygidium minutu?n Eigenmann, Reports Princeton Univ. Exped. Patagonia, III, 



1910, p. 399. 



Habitat. — San Lorenzo district,, southern Rio Grande do Sul. 



Fig. 20. Pygidium minutum (Boulenger). After Boulenger. 



Head 4.5; D. 8; A. 6; eye a httle in advance of the middle of the head, 1.5 in the 

 interorbital ; gill-opening not continued forward to below the eye ; maxillary barbels 

 three-fifths the length of the head, not reaching the gill-opening; nasal barbels 

 extending to the eye; dorsal entirely in front of the anal; origin of dorsal midway 

 between snout and tip of caudal; caudal rounded. Pale brown above, with three 

 longitudinal series of large squarish brown blotches. Fins immaculate, the largest 

 40 mm. 



