FISHES OF THE FAMILY LORICAEIID^E. 205 



/S. Supraorbital edges not raised ; length of mandibular 

 ramus lf-2j in the interorbital width. 

 26 scutes in a longitudinal series ; diameter of eye 

 6^ times in the length of head (in a specimen of 



260 mm.) 16. P. garmani Rgn. 



26 scutes in a longitudinal series ; diameter of eye 7 times 

 in the length of head (in a specimen of 130 mm.) ; 

 caudal peduncle 2f times as long as deep. . . . 18. P. unce Stdr. 



26 scutes in a longitudinal series; diameter of eye 8 times 



in the length of head (in a specimen of 250 mm.) ; 

 caudal peduncle 3 times as long as deep ; abdomen, 

 in the adult, in great part covered with granular 

 scales 19. P. wuchereri Gthr. 



27 scutes in a longitudinal series ; abdomen, in the adult, 



almost entirely naked 20. P. luetkeni Stdr. 



y. Supraorbital edges slightly raised; length of mandibular 



ramus H times in the interorbital width . . . .21. P. auroguttatus .Rner. 



II. Adipose fin small or absent ; operculum and interoperculum with well-developed 



marginal bristles. (Pogonopoma, subgen. n.) 



A. Adipose fin present 22. P. wertheimeri Stdr. 



B. No adipose fin. 



Length of snout 2g- times in that of the head, which is 3| 



times in the total length 23. P. pellegrini Rgn. 



Length of snout twice in that of the head, which is 3-3| 



times in the total length 24. P. genibarbis C. & V. 



III. Adipose fin absent ; operculum and interoperculum not margined with bristles. 



(Rhinelepis Spix.) 



Interorbital width 2|— 2f times in the length of head; opercular plate 



rather large ; abdomen almost entirely naked 25. P. parahybce Stdr. 



Interorbital width l|j- times in the length of head; opercular plate 



very large ; abdomen entirely covered with granular scales . . . 26. P. asper Spix. 



1. Plecostomds guacari. 



Loricaria plecustomus Linn. S. N. i. p. 508 (1766) ; Bloch, Ausl. Fische, viii. pi. 374 (1794) ; 



Bl. Schn. p. 124 (1801). 

 Hypostomus guacari Lacep. Poiss. v. p. 145 (1803). 

 Loricaria flava Shaw, Zool. v. p. 38, pi. ci. (1805). 

 Hypostomus plecostomus Schomburgk, Fish. Guiana, i. p. 139 (1841) ; Kner, Denkschr. Ak. Wien, 



vii. 1853, p. 263. 

 Plecostomus bicirrhosus Gronow, Cat. p. 158 (1854) ; Glinth. Cat. Fish. v. p. 231 (1864) (part.); 



Kner & Steind. Abhandl. bayr. Ak. x. 1865, p. 60; Hensel, Arch. Nat. 1870, p. 75; Steind. 



Denkschr. Ak. Wien, xliii. 1881, p. 109. 

 Hypostomus robinii Gill, Ann. Lye. N. York, vi. 1858, p. 46. 

 Plecostomus braslliensis Bleek. Nat. Verb.. IIoll. Maats. xx. 1864, Silures de Suriname, p. 7. 



