134 OSTAEIOPHTSI. 



Depth of body fi in the length, Ifiiigth of head 5. Breadth of head 1* in its length, length of snout 2|, 

 diameter of eye 51, interorbital -width 4. Lower jaw nearly as long as the upper; width of mouth | the 

 width of head. Maxillary barbel extending nearly to the posterior end ot pectoral tin. Head covered 

 with smooth skin ; occipital process extending i of the distance from its base to the origin of dorsal. 

 9 to 11 gill-rakers on the lower part of anterior arch. Dorsal I 6 ; spine slender, fin rounded. Length 

 of adipose fin 21 in the length of the fish. Anal 14, when laid back not nearly reaching the vertical from 

 the end of adipose fin. Humoral process extending a little beyond the middle of pectoral spine, which 

 has the inner edge serrated and measures |- the length of the fin or -S the length of head. Ventrals 

 inserted behind the last ray of dorsal, extending § of the distance from their base to the origin of anal. 

 Caudal deeply notched, the lower lobe rounded. Least depth of caudal peduncle 2i in the length of head 

 and 2| in the distance from anal to base of caudal. Brownish. 



Ilab. NiCAKAGUA, Lake Managua ^ (iJow). 



Here described from the t3'pe, a specimen measuring 210 mm. in total length. 



11. Kliamdia lieteracantha, sp. n. 



Depth of body 5j in the length, length ot head 41. Breadth of head Ig in its length, length of snout 2-J, 

 diameter of eye 52., interorbital width 3. Lower jaw scarcely shorter than the upper ; width of mouth i 

 the width of head. Jlaxillary barbel extending to origin of adipose fin. Head covered with smooth 

 skin ; occipital process triangular, extending about 4 of the distance from its base to the origin of dorsal. 

 7 giU-rakers on the lower part of the anterior arch. Dorsal I G ; spine slender, fin rounded. Length of 

 adipose fin nearly 3 in the length of the fish. Anal 10. Humeral process extending nearly to middle of 

 pectoral spine, which has the inner edge finely serrated and a series of antrorse denticulations on the 

 outer edge and measures I the length of the fin and f to 4 the length of head. Ventrals inserted behind 

 the last ray of dorsal, extending ~ of the distance from their base to the origin of anal. Caudal 

 moderately notched. Least depth of caudal peduncle 2i in the length of head and l^J in the distance 

 from anal to base of caudal. Brownish. 



Ilab. Costa Eica, Juan Vifias [Underwood). 



A single specimen, measuring 105 mm. in total length. 



12. Ehamdia liypselura. (Tab. XXI. fig. 3.) 



Piiiielodus hijjjselurus, Guuth. Cat. Fish. v. p. 126 (1864)'. 



Rhariidia hijpselurus, .lord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 152". 



Depth of body about 5h in the length, length of head 4*. Breadth of head 1;} in its length, length of snout 

 '■J.-i, diameter of eye S.^-, interorbital width 3. Lower jaw shorter than the upper ; width of mouth 

 slightly more than * the width of head. Jlaxillary barbel extending to middle of dorsal fin. Head 

 covered with smooth skin; occipital process extending f of the distance from its base to the origin of 

 dorsal. 9 gill-rakers on the lower part of the anterior arch. Dorsal I ; spine slender, fin rounded. 

 Length of adipose fin 3^ in the length of the fish. Anal 13. Humeral process extending to middle of 

 pectoral spine, which is = the length of the fin and I the length of head. Yentrals inserted behind the 

 last dorsal ray, extending | of the distance from their base to the origin of anal. Caudal moderately 

 notched. Least depth of caudal peduncle 1 j in the length of head and 11 in the distance from anal to 

 base of caudal. Dark greyish. 



Uah. Mexico ^ {ParudazJd). 



Here described from the type, a specimen measuring 115 mm. in total length. 



