eigenmann: the freshwater fishes of British guiana 245 



c. Head smooth; pores of the head black; plates of the middle of the belly frequently forming 

 transverse scutes with the lateral plates. 

 d. Pectorals, ventrals and anal spotted; an ocellus-like spot on the back in front of the 



dorsal; pores of anterior part of body not black brunneus. 



dd. Pectoral, ventrals and anal with a submarginal band platyurus. 



cc. Head strigilate stewarti. 



110. Loricariichthys microdon (Eigenmann). (Plate XXX, fig. 1 ; Plate 



XXXII, fig. 1.) 

 Loricaria acuta (not of Cuvier and Valenciennes) Muller and Troschel, in 



Schomburgk, Reisen, III, 1848, 631 (sand-bars of the Rupiuuini). 

 Loricaria microdon Eigenmann, Ann. Carnegie Mus., VI, 1910, 7; Repts. Princeton 



Univ. Exp. Patagonia, III, 1910, 414. 



This species is closely allied to, if not identical with, L. acutus. Regan gives 

 the lower lii^ of acutus as entire. 



I have examined- the specimen mentioned by Muller and Troschel. 



Type, 90 mm. Rupununi. (Carnegie Museum Catalog of Fishes No. 1507.) 



Cotj^pes, two specimens, 76 and 112 mm. to tip of middle caudal ray. Rupu- 

 nuni. (I. U. Cat. No. 11942.) 



Head 4-4.6; width of head 1.5-1.66 in its length; eye 6, equal to intcrorbital; 

 snout 2+ in the head; width at first anal ray 5.33-6.33 in its distance from the 

 caudal; scutes 17 or 18 + 14, the keels remaining separate throughout; upper lip 

 not developed in the middle, entire on the sides in the largest specimen, fringed in the 

 type; lower lip notched in the middle, deeply concave on each side in the type; 

 the barbel extending considerably beyond the widest part of the lip, its free portion 

 equal to the eye. Margin of the lower lip notched. Lips smooth. Lower lip 

 in the largest specimen damaged, apparently reaching to the gill-opening, with a 

 marginal fringe of tentacles. 



Teeth excessively minute, twenty or more on each side of the lower jaw; 

 about eight conical teeth on each side of the upper jaw. 



Plates in front of the fourth dorsal ray keeled, a pair of keels on the occipital; 

 eyes with large angular notches, which encroach on the interorbital in the largest 

 specimen. Anal plate pointed in front, bordered by two or three plates, the three 

 together united into a larger plate in the largest specimen ; ventral buckler formed 

 of six plates, apparently only four in the largest ; a single series of plates between the 

 lateral series, two or more series farther forward. Ventral armature reaching to the 

 gill-opening; lower surface of head naked. 



Pectorals truncate, the spine not produced, scarcely reaching ventral ; ventral 



