268 



PROCEEDINGS OF THE ACADEMY OF 



[Apr., 



extend well into front interorbital region. Internasal space 2f in 

 interorbital. Cheeks level or very slightly convex. Interorbital 

 mostly flattened medianly, and as supraorbital ridges slightly 

 elevated of somewhat concave appearance. Opercle large, rather 

 porous. Supraoccipital wide, completely divides truly first predorsal 

 scale. 



Gill-openings lateral, extend forward about opposite hind edge 

 of eye. Gill-rakers about 3+8 short, firm points, about j length of 

 gill-filaments, and latter about 2 in eye. Isthmus broad. Bran- 

 chiostegals broad. 



Scales or scutes, all more or less minutely spinescent. Scutes 

 on belly in rather irregular rows, anteriorly 5, antero-medianly 3, 



Fig. 4. — Loricariichthys derbyi Fowler. (Type.) 



postero-medianly 2, and posteriorly 1. Single preanal scute. Lat- 

 eral keels on each side made up of a series of minute denticles, 

 straight in their arrangement, and graduated longer to last, which 

 largest. Lateral belly scales with scarcely obsolete keels. Head 

 all more or less roughened with minute asperities, though slightly 

 larger along lower edge of snout. All fin spines and outer surfaces 

 of fin rays finely spinescent. 



Dorsal origin at first third in length between snout tip and caudal 

 base, spine slender, and shorter than longest rays when depressed. 

 Anal inserted well behind dorsal base or nearer snout tip than 

 caudal base, and spine shorter than longest depressed rays, fin 

 extending 3| to caudal base. Caudal small, median rays short, and 



