ElGENMANN : THE EXPEDITION TO BRITISH GUIANA. 9 



Head 4.5-5; width of head 1.4-1.5 in its length; eye 5; inter- 

 orbital 6.5-7 ; snout 2 in the head ; width at first anal ray 5-5.33 in 

 its distance from the caudal; i8oriQ-|-ii scutes, the lateral keels 

 remaining separate throughout. 



Upper lip well developed, thickly papillose in the types, and 

 always margined with well-developed tentacles, which are shortest or 

 absent at the center. Lower lip in the type very broad, extending to 

 the middle of the opercle, everywhere minutely warty with a few 

 larger warts on its anterior half, emarginate, otherwise with the edge 

 smooth; lips ordinarily much narrower, not much wider than the part 

 with larger warts, deeply emarginate, and the edge with minute ten- 

 tacles ; free portion of the barbel scarcely half the length of the eye. 



Teeth minute, about 6-8 on each side of the upper jaw and twelve 

 on each side of the lower, those of the upper jaw much smaller than 

 the largest of the lower jaw. 



Head without ridges, an obscure groove on the occipital, sometimes 

 continued in the first or first two nuchal plates ; orbital notch broad 

 and shallow, rounded, not encroaching on the interorbital ; lower sur- 

 face of the head naked ; plates of the body without keels or ridges ; 

 anal plate normally bordered by three plates, but sometimes by four or 

 five ; two to four series of plates between the lateral plates of the belly ; 

 anterior border of the ventral armature on a line with the gill-open- 

 ings ; truncate or emarginate through the development of minute 

 plates on the side in front. 



Pectoral truncate when half expanded, emarginate when depressed, 

 the spine not prolonged, reaching second fourth of the ventrals. Ven- 

 trals usually rounded, or truncate, scarcely reaching the anal ; in a few 

 of the Bartica specimens the inner rays are prolonged, reaching to near 

 the fourth anal ray ; upper caudal ray in a well-preserved specimen 

 2.5 times the length of the middle ray. 



Sand-colored, back everywhere spotted ; very obscure cross-bars ; 

 dorsal, pectoral, and more obscurely the ventral colored like the back » 

 upper part of caudal with cross-bars, tip of lower caudal lobe blackish ; 

 anal hyaline. 



Loricaria stewarti sp. nov. 



Type, 81 mm. over all, 64 mm. to tip of middle caudal ray. (No. 

 1508 Carnegie Museum Catalog of Fishes.) Ghipoo Creek, a tribu- 

 tary of the Ireng. 



