196 CALIFORNIA ACADEMY OF SCIENCES. 



vomerine teeth and the inner ones of the jaws velvety.. 

 Eyes about in the middle of the head; interocular 1 

 inch. (Liechtenstein.) 



143, Brachyplatystoma vaillanti, 



Platystoma vaillanti Cuv. & Val. Hist. Nat. Poiss. xv, 21, plate 423,. 

 1840 (Cayenne & Surinam); Kner, SB. Ak. Wien, xxvi, 1857, 397 

 (Para); Giinther, Cat. Fish. Brit. Mus.v, 108, 1864 (Demarara); 

 Peters, MB. Ak. Berl. 469, 1877 (Calabozo). 



Brachyplatystoma vaillanti Bleeker, Nederl. Tijdschr. Dierkunde, 

 i, 1863, 97 (name only); id. Silures de Suriname 70, 1864 (Suri- 

 nam); Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. vol. i, 1888, 

 136 (Tabatinga; Para; Porto do Moz; Avary; Rio Puty; Juiz de- 

 Fora) . 



Platystoma affine Cuv. & Val. Hist. Nat. Poiss. xv, 1840 (Brazil); 

 Castlenau, Anim. Am. Sud. Poiss. 40, 1855 (Araguay); Giinther, 

 Cat. Fish. Brit. Mus. v, 109, 1864 (copied). 



Platystoma mucosa Vaillant, Bull. Soc. Philom. Ser. 7, iv, 151, 1880- 

 (Calderon). 



Platystoma verrucosum Boulenger, Zool. Record, xix, Pisces, 1880< 

 (name only); a substitute for mucosa Vaillant. 



Habitat: Eastern slopes of South America, north of the Rio 

 Parahyba. 



Cuvier and Valenciennes based their description of 

 vaillanti on specimens from .15 to .38 m. long, and their 

 affine on a specimen .60-. 65 m. long without the caudal. 

 In affine the occipital process does not reach the dorsal 

 armature. 



We have examined specimens from .20 to over .80 m. 

 in length and find that in the young the entire upper 

 surface of the head has the skin ossified and the occi- 

 pital process reaching the dorsal armature. In the larger 

 specimens the head is entirely covered with skin and 

 the occipital process is as described in affine] we have,, 

 therefore, placed it in the synonymy of vaillanti. 



Platystoma mucosa is insufficiently described. It is 

 probably identical with vaillanti. 



Body rather short and deep, its width below first dor- 

 sal spine not equal to its depth. Profile steep, width of 



