242 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



ital. Dorsal short, confined to the abdominal portion of the vertebral 

 column. Opercle well developed and movable ; adipose fin present ; occip- 

 ital process not forming a bony bridge from the occipital to the dorsal 

 plate. Caudal vertebrae not compressed, the neural spines simple, spine- 

 like. Maxillary well developed, provided with teeth and forming the sides 

 of the jaw ; nares approximated ; gill membranes somewhat joined, but free 

 from the isthmus. A single genus. 



4. DIPLOMYSTE. 



Diplomyste Dumeril, Ichthyol. Analyt., 487, 1856 [papillosits). 

 Diplomystes Bleeker, Nederl. Tijdschr. Dierkunde, I, 92, 1863 {papillosus). 

 Diplomystax Giinther, Cat. Fish. Brit. Mus., V, 180, 1864 [pcpillostts). 



The distinctive character of this genus is the development of the 

 maxillary bone. It forms the sides of the mouth and carries a very nar- 

 row band of teeth. No mental barbels ; maxillary barbels thick, com- 

 pressed at the base. Occipital process not visible externally ; no bony 

 orbit. Skull with two nearly parallel median ridges above. Fontanel 

 extending to the base of the occipital process, with a rather broad inter- 

 ruption behind the eyes. A single species. 



Habitat: Chili, near Valparaiso and Santiago. 



8. Diplomyste papillosus (Cuvier & Valenciennes). 



(Plate XXXI, Figs, i, \a and i,^.) 



Molina "Hist. Nat. Chile, 199, No. 9." 



^ISttunis cliilensis Linnaeus, Syst. Nat. Ed. XIII, 1359, 1788 (Chili). 



}} Pinietodiis cliilensis Lacep^de, Hist. Nat. Poiss., V, 114, 1803 (Fresh- 

 waters of Chili). 



Arius papillosits Cuv. & Val. Hist. Nat. Poiss., XV, 118, pi. 431, 1840 

 (Valparaiso; Santiago); Gay, Hist. Chile, II, 305, pi. fig. i, 1848 

 (Chili) Philippi, MB. Ak. Wiss. Berlin, 1866, 710 (Chili). 



Diplomystax papillosus Giinther, Cat. Fish. Brit. Mus., V, 180, 1864 

 (Chili). 



Diplomystes papillosits Eigenmann & Eigenmann, Proc. Cal. Acad. 2d 

 sen vol. I, 1888, 149 (Rivers of Santiago). 



Ariits carcharias " Leybold, Anales de la Universidad de Chili, 1859 

 (Chile)"; Philippi, MB. Akad. Wiss. Berhn, 1866, 711 (Chili). 



