362 CALIFORNIA ACADEMY OF SCIENCES. 



bb. Margin of head in males with numerous bristles; teeth well devel- 

 oped in both jaws; lateral keels coalescing; orbit without a notch; 

 lower surface of the head with small plates; belly with o series of 

 plates; orbit 2 in interorbital; outermost caudal rays produced. Head 

 without keels; anterior profile concave. Head 4i;Lat. 1. 34. 



(Sturisoma.) rostrata 304. 



aa. Snout acute or rounded, not produced. 



e. Margin of the head in males with numerous bristles, which are very 

 minute in brevirostris; teeth well developed; uppermost caudal ray 

 greatly produced; lips not very greatly expanded, fringed or not, with- 

 out long cirri. (Eineloricaria.) 

 /. Orbit without a notch; lower surface of head with numerous small 

 plates; head without keels; loreal region concave; anterior profile 

 slightly concave; belly with 5 series of plates; superciliary margin 

 slightly raised; orbit 3J in the snout; lips narrow, teeth numerous. 



brevirostris 305. 

 ff. Orbit notched; lower surface of head naked; uppermost caudal 

 ray produced, filiform; profile convex. 



g. A rather large anal plate, bordered anteriorly by three plates; 

 snout more or less pointed. 



h. Lower lip two-lobed; occipital with x-shaped keels; mucous 

 pores of the head and anterior part of the body black; all the 

 fins spotted. Superciliary margin raised, nuchal plates strongly 

 bicarinate; granulations of the head arranged in longitudinal 

 series. lima 306. 



hh. Lower lip fringed; occipital with v-shajjed ridges; snout 

 pointed; occipital and nuchal plates in the male with bristles 

 similar to those on the cheeks; all fins faintly spotted. (Stein- 

 dachner.) magdalence 307. 



gg. Region between veutrals with numerous small plates; snout 

 rather blunt; lower lip fringed; plates of the head striate and fur- 

 rowed; all fins with indistinct blackish spots; margin of caudal 

 blackish. (Steindachner.) Jilamentosa 308. 



ee. Margin of head in both sexes granular or hispid. 



i. Plates between veutrals large, more or less firmly connected to 

 form a buckler; a large anal plate. 



j. Belly with a single series of plates. (Hancock.) brunnea 309 

 jj. Belly with 3 or more longitudinal series of plates. 



k. Head as broad as long; orbital notch very shallow; form 

 greatly depressed; no teeth in the upper jaw; occipital keeled; 

 lower lip with cirri; snout with a median groove; margin of 

 snoiit and sides of the head with many short spines. Fins 

 reddish. (Kner.) (Pseudohemiodon.) platycephala 310. 



kk. Head longer than broad. (Parahemiodon.) 



