1903.] FISHES FROM RIO JANEIRO. 65 



Gerres lineatus Humboldt. 



The British Museum possesses only a single example of this 

 species, from Mazatlan. The pectoral is a little longer than the 

 head ; the second anal spine nearly equals in length the second of 

 the dorsal, which is a little less than | the length of head. 

 15 very short gill-rakers on the lower part of anterior arch; 

 6 scales between first dorsal spine and lateral line, and 4 rows of 

 scales between dorsal sheath and lateral line for nearly the whole 

 length of the dorsal fin. 



Apparently this species occurs also on the Atlantic coasts of 

 Tropical America, whence it has been described as G. hrasilianu^ 

 Cuv. & Yal. and Gerres emhryx Jordan & Starks. There is nothing 

 in the descriptions of these species which does not apply to 

 G. lineatus, except that Messrs. Jordan and Evermann give the 

 number of gill -rakers on the lower part of the anterior arch as 11 ■ 

 for G. hrasilianus, but probably this number has been taken from 

 specimens with 7 soft rays in the anal, which are here regarded 

 as belonging to another species, viz. G. patao Poey. 



Gerres axillaris Giinther. 



Three examples of this species from Chiapas agree in having 

 5 scales between the first dorsal spine and the lateral line, and only 

 3 rows of scales between the dorsal sheath and the lateral line for 

 the whole extent of the sheath. There are 12 gill-rakers on the 

 lower part of the anterior arch, which, although short, are longer 

 than in G. lineatus and nearly equal to \ the diameter of eye. 

 In other characters similar to the preceding species. 



Gerres patao Poey. 



The resemblance of this species to G. lineatus is most remark- 

 able, and it is only to be separated from it by the anal with III 7 

 rays, and the fewer and somewhat longer gill-rakers, of which 

 there are about 11 on the lower part of the anterior arch, about 

 4- the diameter of eye in length. Some examples have the pre- 

 maxillary groove densely covered with small scales as far forward 

 as the anterior margin of the eye, but in others these are deciduous, 

 and in some even the premaxillary groove shows no trace of having 

 been scaly, so that this is an unsafe character to use in specific 

 diagnoses. 



Hah. Atlantic coast from Cuba to Bahia. 



Triglid^e. 

 Prionotus beanii Goode. 



This species has hitherto been known only from one specimen, 

 from off Trinidad, and the taking of another at Rio Janeiro seems 

 worth recording. 



Peristedion altipinnis, n. sp. (Plate YIII. fig. 1.) 

 Depth of body S^-Sf times in total length, length of head 

 Proc. Zool. Soc— 1903, Yol. II. No. Y. 5 



