10 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxnr. 



Scales 6-31-4:; A. 20; head about 4; depths; eye 2.6, twice as long 

 as snout, but very little greater than interorbital; maxillary short, 

 not extending beyond front of eye, with two teeth; mouth small, teeth 

 all 1)road-tipped and multicuspid, about 5 in each premaxillary, 4 or 5 

 in each ramus of the lower jaw. Dorsal profile arched; origin of 

 dorsal midway between tip of snout and base of caudal. Pectoral 

 short, just reaching ventral; ventrals not to anal. No humeral spot; 

 a well defined caudal spot not extending to the ends of the middle 

 rays, otherwise plain. 



Odontostilbe microcephalus Eigenmann, new species. 



Type. — No. 11086, Museum of Indiana University. Specimen 46 

 mm. in total length. Rio Pilcomayo, Bolivia. 



Cotype. — No. 11086«, Museum of Indiana University. Specimen 

 45 mm. in total length, from the same locality. 



Both these specimens were received in exchange from the British 

 Museum, and were labelled Cheirodon pequira. They lack the com- 

 plete dentition and the peculiar marking of the dorsal of pequira. 

 They seem to represent a new species of OdontoHt'dhe in its narrowest 

 sense; that is, the teeth are in a single series, the maxillary has but 

 few teeth, and the lateral line is complete. This species is very nearly 

 allied to if not identical with fugitiva. 



Head 4.33; depth 4; D. 10; A. 18-20; scales 6-36-5; eye 3 in head, 

 equal to interorbital. 



Elongate, slender, the dorsal and ventral profiles very little arched; 

 head very small, slightly convex; frontal fontanel reaching about to 

 middle of eye; mouth small, the maxillary slender, reaching to below 

 margin of eye; teeth broad, many pointed, the middle point promi- 

 nent, 5 in each premaxillary, 1 on the maxillary and 6 graduated 

 ones on the mandibles; cheeks mailed, a narrow naked area betw^een 

 suborbitals and the vertical limb of the preopercle; origin of dorsal in 

 the middle of the length, behind the base of the ventrals; pectorals 

 not reaching ventrals, ventrals not to anal; caudal much longer than 

 head; lateral line decurved, running below middle of body. A silvery 

 latei'al band, a dusky spot at base of caudal. 

 Aphyocharax rathbuni Eigenmann, new species. 

 Aphyocarax anisUsl (part), Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 



1903, p. 517. 



TyjJe. — No. 10025 museum of Indiana University; specimen 26 mm. 

 to base of caudal, Arroyo Chagalalina, Paraguay Basin. 



Head 4; depth 3; A. 20; D. 9; scales 5-35-3; eye 3 in head, about 

 twice as long as snout; mouth minute, maxillary not reaching anterior 

 margin of orbit, its free surface very much convex; no teeth on max- 

 illary, about 5 on each premaxillary and about 6 on each side of the 

 lower jaw, the middle one much the largest, the next two graduated, 

 the lateral ones miiuite; pectorals not quite reaching ventrals, ventrals 



