200 



CALIFORNIA ACADEMY OF SCIENCES. 



Head 3f ; depth 54-6; Br. 12 or 13; D. I, 6; A. 15. 

 Two specimens, from Para. 



XXXI. DUOPALATINUS. 



Buopalatinus Eigeiim. & Eigenm. Proc. Cal. Acad. 2d 

 Ser. i, 136, 1888 (eTnarginatus). 



Type: Platystoma einarginatmn Cuv. & Val. 



Teeth all alike, the vomerine patches far removed from 

 the palatine patches. 



This genus is closely related to Bracliy platystoma from 

 which it differs in the nature and position of the teeth. 



146. Duopalatinus emarginatus 



Platystoma emarginalum Cuv. & Val. Hist. Nat. Poiss. xv, 25, 1840 

 (San Fraucisco); Liitkeu, Dau. Selsk. Skr. 1875, 152, fig. (Kio 

 das Velhas). 



Duopalatinus emarginatus Eigeum. & Eigenm. Proc. Cal. Acad. 2d 

 Ser. i, 1888 (Eio das Velhas; Eio San Francisco below the falls). 



Habitat: Kio San Francisco and its tributaries. 



This species being the sole representative of the genus 

 can most readily be distinguished by its teeth. 



Head narrow, little depressed; width at angle of mouth 

 11 in greatest width, 2j in its length; its greatest depth 

 2^ in its length; upper jaw scarcely projecting. 



Maxillary barbel reaching to anal; mental barbel ex- 

 tending to base of pectoral, the postmental to tip of pec- 

 toral. 



0^ 



Teeth of the upper jaw 

 in a band which is not 

 much narrower at the mid- 

 dle; vomerine teeth, in 

 the young, in two small 

 ovate patches distinct 

 from each other; in much larger 

 united patches in adult; palatine 

 patches ovate, removed from the vo- 

 merine patches. 



V^ 



