406 CALIFORNIA ACADEMY OF SCIENCES. 



Dr. Steindachner states that the museum at Cambridge 

 has specimens of this species from the localities quoted. 

 We have not been able to find them. The species is ev- 

 idently closely related to PL plecostomus; all the speci- 

 mens of PL plecostomus examined by us have 26 series of 

 lateral scutes, while this possesses 30. 



349, Plecostomus plecostomus, 



Acipenser plecostomus Linnaeus, ed. x, 238, 1857. 



Loricaria plecostomus Linnaeus, ed. xii, 508, 1766 (America); Lin- 

 naeus, ed. xiii, 1363, 1788; Bloch, Ausland Fische, 8, pi. 374, 

 1794, "Bloch & Schneider, Syst. Ichthyol. 124, 1801;" Hyrtle, 

 Denk. Ak. Wien, xvi, 18, 1859 (vertebrae 1+20). 



Hypostomus plecostomus Cuv. & Val. Hist. Nat. Poiss. xv, 489, 1840 

 (Maracaibo); Schomburgk, Fish. Guiana, part i, 139, 1841 (Bio 

 Branco); Kner, Hypostomiden, 263 (Ypanema; Matogrosso; 

 Barra do Kio Negro; Surinam). 



Plecostomus plecostomus Eigenm. & Eigeiim. Proc. Cal. Acad. 2d Ser. 

 i, 168, 169, 1888 (Silva, Lake Saraca; Para; Hyavary; Coary; 

 Kio Puty). 



Hypostomus guacari Lacepede, v, 145, 1803 (America). 



Loricaria flava Shaw, "Zool. v, 38, pi. 101, 1805." 



Plecostomus flavus Vaillant, Bull. Soc.Philom. series 7, iv, 155, 1880 

 (Calderon). 



Hypostomus verres Cuv. & Val. Hist. Nat. Poiss. xv, 365,"1840. 



Plecostomus bicirrhosus Gronow, "Cat. Fish. 158, 1854;" Giinther, 

 Cat. Fish. Brit. Mus. v, 231, 1864 (Guianas; Cayenne; Para); 

 Kner & Steindachner, Abhandl. Bayr. Akad. Wiss. x, 1, 60, 1865; 

 Hensel, Wiegm. Arch. 1870, i, 75 (Rio Cadeo); Steindachder, 

 Flussfische Sudani, ii, 109, 1881. 



Plecostomus brasiliensis Bleeker, Silures de Suriuame, 7, 1864 (Su- 

 rinam). 



Habitat: Bio Puty; Amazons and northward. 



Head pointed, a strong keel on either side from nares 

 to occiput; occipital bone with a strong keel; nuchal 

 plates conspicuously bicarinate. Scutes of upper half 

 of body more or less strongly keeled. .Humeral keel 

 strong, extending backward not beyond the 8th scute; 

 the lower two series of scutes without carination. Lower 

 surface of the caudal portion of the body rounded simi- 

 lar to the dorsal surface of the same region. A distinct 



