THE CYPRINODONTS. 43 
equal depth between dorsal and anal, two ninths of the length to the base of 
the caudal, slightly arched on the crown. Snout short, less than eye, form- 
ing a nearly regular curve from orbit to orbit. Mouth small, narrow, directed 
upward ; lower jaws longer, rather firmly joined ; upper shorter, protractile. 
Outer series of teeth slender, narrowed at the base, broadened toward the 
apex, hooked ; inner small, in bands, one cusped, with a slight expansion at 
each side near the point. Eye nearly twice in the snout, nearly three times 
in the head, one and one half times in the forehead. Dorsal origin about 
midway from head to base of caudal, about opposite that of anal. Anal of 
male farther forward, between the ventrals, intromittent portion little less 
than half the length of the body to the base of the caudal. Ventrals small, 
not reaching the anal, number of rays varying from five to six, in cases five 
rays on one side and six on the other. Pectorals small, reaching behind a 
vertical from the bases of the ventrals. Caudal deep, median rays longer 
than the head, convex. 
Light olivaceous, edges of scales darker, lighter below. A lighter to 
silvery streak along the lateral line. Larger specimens nearly uniform, 
reticulated, belly silvery. Top of head darker; cheeks and throat silvery. 
About half the specimens are marked by a vertical spot of black, on the 
twelfth or thirteenth scale forward from the middle of the tail, little behind 
the base of the dorsal, on the middle of the flank. Commonly on the smaller 
specimens there are eight or more narrow vertical bars on the flank, the 
black spot appearing in one of them. Dorsal and caudal frequently and anal 
sometimes tipped with darker. A darkish transverse band in the dorsal and 
small spots on dorsal and caudal are not rare. Mature females one and one 
half, and males three fourths inches in length. 
Maldonado ; Rio Janeiro ; Rio Negro; Campos; Muriahi; Santa Rita; 
Villa Nova; Santa Anna. 
CNESTERODON. 
These fishes are intermediate between Glaridodon and Girardinus. The 
mouth resembles that of Girardinus, but the teeth are broader and few in 
number. The incisors are broader and stronger than those of Glaridodon, 
but the jaws are not so firmly united. As seen in Plate VIII. Figs. 16, 17, 
the modification of the anal fin of the male differs from that of both Glarido- 
don and Girardinus, Plate VIII. Figs. 13-15, and approaches that of Gam- 
busia. In the specimen dissected there were no subvertebral processes for 
