PLECOSTOMUS. Ill 



C. Body scaly. 



M outh toothless ; gill-membranes joined to the isthmus ; no adipose fia . . 3. Cyprinid^. 



Jaws with teeth ; mouth bordered laterally by the maxillaries ; gill-membranes 

 free from the isthmus ; 3 to 5 branchiostegals ; an adipose fin often 

 present ; lateral line usually present and running along the middle of the 

 side; pectoral fins placed low 4. Characi.vid.t;. 



II. No ventral fins; no dorsal ; a long anal ; body more or less eel-shaped . 5. Gymnotid.e. 



ram. 1. LORICARIID^. 



The LoricariidiE are fresh-water fishes of South America, ranging from Panama to 

 Monte Video. There are about 200 species, of which seven are known from Panama. 

 These may be recognized by the series of bony plates which protect the body, the 

 restricted gill-openings, and the inferior mouth with expanded sucker-like lips. The 

 dorsal fin is anterior in position, the anal fin is short, and the uppermost and lowest 

 rays of the caudal and the first ray of each of the other fins are simple and often 

 spinous. 



Synopsis of the Genera represented in Central America. 



I. Caudal peduncle compressed or cylindrical. 



A. Snout granular to its margin. 



Operculum and interoperculum little, and not iadependently, movable ... 1. Plecostomus. 

 Interoperculum freely movable, spinate 2. Ancistrus. 



B. Snout with a naked margin. 



Snout without tentacles 3. Ch/etostomits. 



Snout with tentacles 4. Xbnocara. 



II. Caudal peduncle strongly depressed. 



Teeth not setiform ; snout not much produced j an orbital notcli ... 5. Loricaria. 

 Teeth numerous, setiform ; snout produced; no orbital notch .... 6. Oxyloricaria. 



1. PLECOSTOMUS, Gronow. 



Plecostomus, Regan, Trans. Zool. Soc. xvii. 1904;, p. 20.2. 



Body more or less elongate, protected on each side by 5 longitudinal series of bony scutes ; upper surface of snout 

 covered with granular plates to its margin ; operculum and interoperculum little, and not independently, 

 movable. Teeth slender, bifid, in a single series. Adipose fin usually present and supported by a 

 movable spine. 



About thirty-five species from Tropical America. 



1. Plecostomus guacari, Lacep. 



Loricaria plecostomus, Linn. Syst. Nat. i. p. 508 (1766). 



Plecostomus guacari, Regan, Trans. Zool. Soc. xvii. 1904, p. 205. 



Dorsal I 7. Anal I 4. 25 or 26 scutes in a longitudinal series, the anterior and superior scutes keeled. 



