SOUTH AMERICAN NEMATOGNATHI, 39 



Genidens ctivieri Castlenau, Auim. Nouv. ou Kares Ainer. Sud, Poiss. 

 34, 1855 (La Plata and tributaries); Gtlnther, Cat. Fish. Brit. 

 Mus. V, 175, 1864 (Brazil); Kner, Novara Fisch. 312, pi. xii, figs. 

 3-3a, 1869 (Eio Janeiro); Hansel, Wiegm. Arch. 1870, i, 71 

 (Guahyba and tributaries); Steindachner, SB. Ak Wien, Ixxiv, 

 1876. Siisswasserfische siidiistlichen Brasiliens, iii, 89 (Gua- 

 hyba; Kio Janeiro; Kio S. Matheos; Porto Seguro; Santos). 



Genidens granulosus Castlenau, Anim. Nouv. ou Eares Amer. Slid, 

 Poiss. 34, pi. xvi, fig. i, 1855 (Eio Araguay, Prov. of Goyaz, 

 Brazil). 



? Laukidi Schomburgk, Fish. Brit. Guiana, part i, 176, 1843 (in i^art). 



Rhamdla laukidi Bleeker, Nederl. Tijdsch. Dierkunde, i, 208, 1863 

 (name only). 



Habitat: Eio Plata audits tributaries north to the Araguay; ? Brit- 

 ish Giiiana. 



We have examined 33 specimens .11-.41 m. from Porto 

 Alegre; Santos; Sambaia; Rio Janeiro; Rio Sao Matheos; 

 Rio Grande do Sul. As in many cases, Schomburgk has 

 described two fishes under his Laukidi. The color be- 

 longs to this species — everything else to some other fish; 

 -as the color comes first in the description, the name 

 lauJvidi should stand a synonym of genidens.^ 



Width behind the head little greater than the depth. 

 Transverse section of the postorbital portion of the head 



*Schomburgk says in his Fishes of British Guiana, part i, 82: "I had 

 nothing to guide me in my researches. The scientific Ichthyologist may 

 therefore be disappointed in my remarks." And on page 83: " The first 

 specimen of any fish, a drawing of which we did not previously possess, 

 served generally to sketch its outward form and general colours on the 

 paper; and when we were fortunate enough to secure a second specimen, 

 those delicate hues were painted in, which are only visible immediately 

 after the fish comes out of water, and which so quickly vanish when life 

 is extinct." It is to this last statement that we must attribute the fact 

 that so many of Schomburgk's fishes are composites, the color belonging 

 to one, the structure to another fish. Schomburgk's notes were edited by 

 Jardin, who often referred the wrong drawing to the descriptions. That 

 these facts are true may be seen from Eichard Schomburgk's statement, 

 Fauna and Flora Brit. Guiana, iii, 618. " Leider sind in Folge von 

 Missgriffen, die ein anderer Verfasser nach den ihm vorliegenden Ab- 

 bildungen und Bemerkungen machte, in Eitcksicht der Gattungen eine 

 Menge Irrthiimer in diese Arbeit gekommen, wie auf der anderen Seite die 

 dem Buche beigefiigten Abbildungeu nur in wenigen Fallen auf Treue 

 Anspruch machen konneu." 



