1886.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 343 



ee. Region above base of pectorals witliout black spot. 

 /. Body very sleuder, the depth 7 in head, which i.s 2§ in body ; 6?ye mod- 

 erate, 2^ to 2f in postorbital i>art of head ; no dis- 

 tinct notch in the temporal ridge, maxillary not 

 entirely concealed by preorbital. D. 1, 15: A, 1, 



17. Lat. 1. 225 Subtruxcatus, 4. 



ff. Body less sleuder, the depth 6 in head, which is 2-p^ in body ; eye large, 

 2^ in postorbital part of head ; a distinct notch on 

 temporal ridge close behind eye ; maxillary almost 

 entirely concealed by the preorbital. D.l, 15; A. 



1,17. Lat.1.200 EURYOPS, 5. 



00. "Caudal peduncle very much depressed, wider than deep, but without any 



keel or trace of one. Head 2f in length; eye 2^ 

 in postorbital part of head ; top of head nearly 

 smooth; maxillary nearly concealed by preorbital ; 

 body subterete ; caudal moderately emarginate; 

 snout very nearly twice length of rest of head; 

 . brownish above, silvery below, a bluish lateral 



stripe edged below with black and yellowish ; 

 scales not very small (23 rows between dorsal and 

 anal tins). D. 16; A. 17." (Cojje.) ..Diplotmnia, 6. 

 ooc. Caudal peduncle more or less depressed, or at least, with a more or less de- 

 veloped dermal keel along the lateral line; scales 

 and bones more or less green. 

 g. Dorsal and anal fins short, each of 14 to 19 rays, the anal larger than 

 the dorsal and beginning farther forward; last 

 rays of dorsal and anal low; jaws slender, about 

 twice as long as rest of head ; no folds of skin 

 across preopercle. 

 h. Eye very small, 4 to 5 times in postorbital part of head ; caudal keel 

 sharp, black in color; body and tail much depressed; 

 maxillary not entirely hidden by preorbital; cau- 

 dal lunate, the lobes subequal; scales minute. 

 i. "Postorbital part of head rather more than half length of snout, 

 its length 5 times diameter of eye ; ventrals a 

 little nearer head than base of caudal; head 3 in 

 length, D. 1, 14 ; A 1, 15." (Gunther). MiCROPS, 7. 

 M. "Postorbital part of head 2f in length of snout; lis length 4 

 times that of eye ; ventrals midway between head 

 and base of caudal ; head about 2f in length." 



(Steindaclmer) Amazonicus, 8. 



hh. Eye moderate, 2 to oj times in postorbital part of head. 



j. "Caudal fin forked ; caudal keel sharp, broad and conspicuous; 

 top of head flat, striated, without median groove; 

 base of upper jaw much depressed ; maxillary 

 entirely hidden by preorbital; teeth very small; 

 ventral fin midway between eye and caudal ; scales 

 not very small. D. 1,13: A. 1, 18." (&imther.) 



Ardeolus, 9. 

 jj. Caudal fin unequally lunate, the euiargiuation not deep, the 

 lower rays moderately produced; scales very 

 small ; sides with a silvery lateral stripe ; caudal 

 keel not very conspicuous, not black; top of head 

 with median groove ; maxillary not entirely con- 

 cealed by preorbital ; ventral inserted midway 



