38 THE CYPRINODONTS. 
depressed, broad, short, one fourth of the length. Mouth small; lower 
jaw prominent. Teeth small, tricuspid. According to Bean the small inner 
teeth were overlooked in the original description. Eye two sevenths of the 
head, little more than half of the interorbital space. Fins small; dorsal 
slightly in advance of anal; caudal short; pectorals not reaching the 
ventrals. 
Bluish above; a silvery streak along each row of scales. Vertical fins 
chiefly black, especially on the distal half. Intestinal tract considerably con- 
voluted, and filled with mud. From a salt lake in a volcanic basin. 
Guanajuato, Mexico. (Jordan.) 
The position of this species is still to be questioned. Bean says, “a 
recent examination of the types of Goodea atripinnis Jordan, proves the exis- 
tence of villiform teeth behind the incisors, and throws Goodea into the 
synonymy of Characodon.” Jordan says Goodea “ differs from most of the 
other Cyprinodontide in its tricuspid teeth. From Cyprinodon, Jordanella, 
Fitzroyia, Characodon, and Jenynsia, the genera thus far known with tricuspid 
incisors, it is distinguished by the elongate intestines, and by the freeness 
of the dentary bones. The aspect is wholly unlike Cyprinodon, resembling 
rather Fundulus.” 
Characodon has two cusps on the teeth and has mandibles rather firmly 
joined. These are characters of more weight than the presence of viliform 
teeth. From the description, we should hesitate in placing the species 
atriinms in Characodon; but, in deference to the more recent researches, 
it is provisionally allowed to remain there until we are able to examine 
specimens. 
GIRARDINICHTHYS. 
Girardinichthys Blky., 1860, Cypr., 481, — 1863, Atl. Ichth., III, 139. 
Limnurgus Gthr., 1866, Cat., VI, 309. 
Compressed in body and head ; caudal pedicel of moderate depth. Head 
short, narrow forward. Snout short, blunt, chin very steep. Mouth small, 
directed upward; lower jaws longer, firmly united; upper short, very pro- 
tractile. Compressed teeth in the outer series. Gill openings wide ; mem- 
branes short, partly united, free from the isthmus. Scales medium. Intestine 
short. Bases of dorsal and anal short, opposed, behind the middle of the 
body; rays numerous. Anal fin not modified in the male. 
Mexico. 
