PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 315 



This species is generally common along the Pacific coast of tropical 

 America. It has no analogue among the Atlantic species. On account 

 of the peculiarities of the form of the body, the mouth, and the vertical 

 fins, and especially the increased development of the gill-rakers, we may 

 regard it as the type of a distinct subgenus, which we may call Lythru- 

 Ion. Its cranium has not been examined, but it will probably be found 

 to differ somewhat from the usual type in Himiulon. 



20. Haemiilon maculicauda. 



Orthostwchus maculicauda, Gill, Proc. Ac. Nat. Sci., Pbila., 1862, 2bo (Cape San 



Lucas). 

 Ecemulon maculicauda, Steindachxer, Ichth. Beitr., iii, 14, 187.5 (Mazatlau ; 



Acapulco). 

 JDiabasis maculicauda, Jordan & Gilbert, Bull. U. S. Fish Comm., 1881, 325 ; 



1882, 110 (Panama) ; Jordax & Gilbert, Proc. U. S. Nat. Mus., 1882, 362, 



372, 626 (Cape San Lucas; Panama ; Colima). 

 Ecemulon maeatlanum, Steixdachner, Ichth. Notizeu, viii, 12, taf., vi, 1809 



(Mazatlani. 



Habitat. — Pacific coast of tropical America, Cape San Lucas to Pan- 

 ama. 



Head, 3J (3f) ; depth, 2f (3i). D. XIII (rarely XIV), 15; A. Ill, 10. 

 Scales, 5i-51-ll. Length (29256, Panama), 8^ inches. 



Body oblong-elliptical, not much compressed ; the back little ele- 

 vated. Head rather large, moderately pointed anteriorly ; the profile 

 nearly straight from the snout to the nape. Snout short, low, rather 

 pointed, its length 3J in head. Mouth small, a little oblicjue, the maxil- 

 lary extending to front of pupil, its length 2| in head. Lower jaw slightly 

 included. Teeth small, the outer and posterior little enlarged. Preor- 

 bital narrow, its least breadth 7| in head. Eye large ; 3f in head in 

 adult. Interorbital space moderate, convex, 3| in head. Preopercle 

 moderately serrate. Gill-rakers slightly longer and more numerous 

 than in most other species, about 16 on lower x)art of arch, the longest 

 about half depth of preorbital. 



Scales large, very uniform in size over the body, arranged above as 

 well as below lateral line, in longitudinal series, those above lateral 

 line being everywhere parallel with the lateral line. Soft fins, scaly, as 

 usual. 



Dorsal spines usually 13, but sometimes 14, in number, rather slender 

 and low, the longest 2jL in head. Soft dorsal low, the longest rays 3i 

 in head. Caudal moderate, the upper lobe If in head. Anal rather 

 low, the longest rays not reaching, when depressed to middle of last 

 rays, their length about 3 in head. Second anal spine stronger and 

 longer than third, 2^ in head, its tip about reaching base of last ray. 

 Yentrals, If in head ; pectorals, 1}. 



Color dark brown; each scale of back and sides with a light, pearly 

 gray spot on its middle, these coalescing into continuous light stripes 

 which are sharply defined, one for each row of scales; head plain; fins 

 plain grayish ; a large dusky area on base of caudal. 



