EHAMDIA. 131 



Depth of body 7 in the length, length of head 4|. Breadth of head 1| in its length, length of snout 2?, 

 diameter of ej-e oj, interorbital width 4. Jaws iiearlj' equal anteriorly ; width of mouth j the width of 

 head. Maxillary barbel extending to origin of adipose fin *". Head covered with smooth skin ; occipital 

 process extending 4 of the distance from its base to the origin of dorsal. 11 gill-rakers on the lower 

 part of the anterior arch. Dorsal I G ; spine slender, fin rounded. Length of adipose fin 24 in the 

 length of the fish. Anal l.'j. Humeral process extending slightly beyond the middle of the pectoi'al 

 spine, which is about | the length of the fin and nearly | the length of head, "^^entrals inserted beliind 

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

 notched. Least depth of caudal peduncle 2= in the length of head and 2| in the distance from the anal 

 to the base of caudal. Brownish. 



Hal). Lake Nicakaglu ^ {Bow). 



Here described from the type, measuring 190 mm. in total length. 



4. Rhamdia boucardi. (Tab. XX. fig. 3.) 



H Rhamdia depressa, Barbour & Cole, Bull. Mus. Comp. Zool. 1. 1906, p. 155, t. 1 ' f- 

 Pimelodus boucardi, Regan, Ann. Mag. Nat. Hist. (7) xix. 1907, p. 258 '. 



Depth of body 64 in the length, length of head 4. Breadth of head li in its length, length of snout 2|. 

 diameter of eye 6, interorbital width 3. Lower jaw nearly as long as the upper ; width of mouth 5. the 

 width of head. Maxillary barbel extending to origin of adipose fin. Head covered with smooth skin ; 

 occipital process rather strong, extending 4 the distance from its base to the origin of dorsal. 12 or 13 

 gill-rakers on the lower part of the anterior arch. Dorsal I 6, the spine slender, the fin rounded. 

 Adipose fin ^ the length of the fish. Anal 14 ; when laid back nearly reaching the vertical from 

 the end of adipose fin. Pectoral spine with serrated inner edge, about 4 the length of the fin and 3 the 

 length of head ; humeral process long, nearly reaching tlie middle of the fin. Ventrals originating nearly 

 below the last dorsal ray, extending more than -s- of the distance from their base to the origin of anal. 

 Caudal deeply notched, the lobes rounded, the lower the large)-. Least depth of caudal peduncle 3 in the 

 length of head, and 2j in the distance from anal to base of caudal. Blackish. 



Ilah. Mexico, Yucatan ^ [Boucard). 



Here described from the type, a specimen measuring 190 mm. in total length. 



5. Ehamdia wagneri. 



Pimelodus cinerascens (nou Giiutli.), Kuer &- Steincl. Abhaudl. Bayern. Akad. x. 1865, p. 49'. 



Pimelodus ivagneri, Giintli. Trans. Zool. Soc. vi. 1868, p. 474". 



Rhamdia Iransfordi, Gill, Proc. Ae. Philad. 1876, p. 337'. 



R/iamdia wagneri, .lord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 131 '. 



Depth of body about 6 in the length, lengtli of head 44 to 4^. Breadth of head 1| to 1 3- in its length, length 

 of snout 2-3- to 2|, diameter of eye 6 to 7, interoi'bital width 23- to 3. Lower jaw nearly as long as the 

 upper; width of mouth about -s- the width of head. Maxillary barbel extending about to the origin of 

 adipose fin. Head covered with smooth skin ; occipital process extending 4 of the distance from its base 

 to the origin of dorsal. 7 to gill-rakers on the lower part of anterior arch. l)orsal I ; spine slender, 

 fin rounded. Length of adipose fin 23- to 3 in the length of the fish. Anal l(i-12, wlien laid back 

 nearly reaching the vertical from end of adipose fin. Humeral process extending about to the middle of 



* As described by Giinthcr. Both barbels are now broken off in the type, the longest reaching the middle 

 of the dorsal. 



t Rhamdia depressa is probably the same as li. houcardi, but the description is insufficient and the figure bad. 



S 2 



