92. CALLICHTHYS. 227 



lateral shields, of which there are only twenty-six in the upper series, 

 and from twenty-four to twenty-five in the lower. A naked space 

 on the back, with a strip of small scales before the adipose fin, as in 

 C. asper. The shields below the adipose fin are separated from its 

 base by a naked interspace. The barbels extend to, or nearly to, 

 the middle of the humeral process. Caudal fin rounded ; pectoral 

 spines covered with fine bristles. Uniform dark greenish olive. 

 Rio Grande. 



a-d. Adult and half-grown. Purchased of Mr. Stevens. 



3. Callichthys knerii. 



Gill, in Ann. Lye. Nat. Hist. Nctv York, 1858, vi. p. 394. 

 D.||l. A. 1/6. P. 1/7. V. 6. 



No osseous shields between the pectoral fins, the lower parts being 

 naked. Pectoral spines compressed, strongly serrated on their edge, 

 their external side being beset with rather strong, recurved, tooth- 

 like spines. Caudal rays barred with brownish black. (Gill.) 



Trinidad. 



4. Callichthys cselatus. 

 Cuv. Sf Vol. xv. p. 308. 



D.i|l. A. 1/4. P. 1/7. V. 6. 



No osseous shields between the pectoral fins, the lower parts being 

 iaked. Nuchal plates very large, interparietal and temporal plates 

 with a transverse groove. Caudal fin rounded. Blackish green. ( Vol.) 



Bahia. 



5. Callichthys littoralis. 



Callichthys littoralis, Hancock, Zool. Journ. 1829, iv. p. 244. 



subulatus, Cuv. Sf Vol. xv. p. 311. 



lsevigatus, Valenc. in aV Orb. Vox/. Amer. Mcrid. Atl. Poiss. pi. 5. 



fig. 2 ; Cuv. $ Vol. xv. p. 314 ; Kner, Sitzgsber. Wien. Acad. 1855, 



xvii. p. 109. 



albidus, Cuv. 8f Val. xv. p. 316. 



Hoplostemum L-evigatum, Gill, in Ann. Luc. Nat. Hist. Neic York, 



1858, vi. p. 396. 

 stevardii, Gill, I. c. p. 401. 



D. || 1. A. j. P. JL. V. 6. Vert. 12-13/11. 



A pair of large osseous shields, in old individuals covered with skin, 

 between the pectoral fins. Twenty-four lateral shields in the upper 

 series, and twenty-three in the lower; a series of about nine or 

 twelve small azygos shields runs from the adipose fin nearly to the 

 dorsal, separating the lateral shields of both sides. Infraorbital bone 

 as wide as, or even wider than, the orbit in full-grown examples, 

 but rather narrower in immature individuals. The barbels extend 



Q2 



