("tchlid Genera Rctroculus, Goopliagu.^, (C*c. (il 



liody moderately eloiij^ate, compressed ; scales lar;;o, 

 ctenoid. Two Literal lines, the upper running oblicjueiy 

 upwards to the spinous dorsal, from which, it' complete, it is 

 separated by not more than 1 series of scales for most of its 

 course; jjosterior part of u|)pcr lateral line and the lower 

 Hue sometimes wantin<;, Mouth small ; maxillary exjjoscd 

 or not ; a band of small conical teeth in cacli jaw; upj)cr 

 surface of head scaly to between the orbits ; checks and 

 opercular bones scaly; praeopcrculum entire. A lobe on 

 the upper part of the anterior branchial arch ; gill-rakers 

 very few and small, sometimes entirely wanting. A single 

 dorsal fin, with XV-XVI 5-7 rays. Anal with III 0-7. 

 Dorsal and anal fins sealeless. Pectoral asymmetrical, with 

 11-1^ rays. Caudal rounded or pointed. 



Five or six species from S. America. 



Synopsis of the Species. 



I. Latenil linos complete. 



Suout much slmrter than eye ; last dorsal spine more 



than 5| the lenp^th of head 1. tfBniatum. 



JSnoiit nearly as lonj? as eye; last dorsal spine ^-§ the 



leUj^lh of head , . 2. Agasmzii. 



II. Upper lateral line fully developed on 3-10 scales only ; lower 



hitf lal line rudimentary or wanting'. 



A. Dorsal spines subequal from the .seventh ; caud.il peduncle \ as 



long as deep 3. liorellii. 



B. Dorsal spines subequal from the fourth ; caudal peduncle from j 



to as long as deep. 

 LeniTth of head ' the length of the fish and '6\ times 



the interorbital width (in a specimen of .j8 mm.). 



A dark stripe from eye to base of caudal ; a dark 



stripe along each series of scales on the lower part 



of tlie body 4. commbr<e. 



Length of hoiid ;' the length of the fi.<h and ■i\ times 



the inter irbital width (in a .specimen of 3U mm.). 



A dark stripe from eye to bik>e of caudal ; an 



oblique dark stripe from base of pectoral to origin 



of anal 5. trifaaciatuui. 



1. Heterogramma ticniaium. 



^fcg'>ps tiPniafiix, (Idnth. Cat. Fi.-h. iv. p. 31 1' (1862). 

 (Jeophfiyns (^Mesups) tceiiiatus, Steind. Sitzb. Ak. Wien, l\.\i. If^To, 

 p. 115. 



as a substitute for Misojys, which is preoccupied. I am quit^^- in agree- 

 ment with IMlegrin in re-'arding 3/. cupido a^ RGeoj>ha(jii.'nmd M. ((cnia- 

 tux and its allies as genencally distinct; but the name Biotodoma cannot 

 be applied to the latter. 



