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 airijnnnis Jordan, proves the exis- 

 tence of villiform teeth behind the incisors, and throws Goodea into the 

 S3monymy of Characodon." Jordan says Goodea " differs from most of the 

 other Ci/prinodontidce in its tricuspid teeth. From Cypnnodon, Jordamlla, 

 Fitzroyia, Characodon, and Jeni/mia, 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 Cypnnodon, 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 

 airipinnis 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. 



Oirardiidchtht/s Blkr., ISGO, Cypr., 481, — 1S63, Atl. Ichth., Ill, 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. 



